Recent advances in omics technologies have led to unprecedented efforts characterizing the molecular changes that underlie the development and progression of a wide array of complex human diseases, including cancer. As a result, multi-omics analyses—which take advantage of these technologies in genomics, transcriptomics, epigenomics, proteomics, metabolomics, and other omics areas—have been proposed and heralded as the key to advancing precision medicine in the clinic. In the field of precision oncology, genomics approaches, and, more recently, other omics analyses have helped reveal several key mechanisms in cancer development, treatment resistance, and recurrence risk, and several of these findings have been implemented in clinical oncology to help guide treatment decisions. However, truly integrated multi-omics analyses have not been applied widely, preventing further advances in precision medicine. Additional efforts are needed to develop the analytical infrastructure necessary to generate, analyze, and annotate multi-omics data effectively to inform precision medicine-based decision-making. A major goal of biomedical research is to identify accurate, early indicators of disease. Over the past decades, advances in technology have ushered in an unprecedented era in biomedical research. Rather than focusing research efforts on individual molecules, pathways, or cells of interest, new technologies now allow characterization of complex biological systems in great detail and at unparalleled resolution. Sequencing technologies have helped decipher the genetic code of numerous organisms, including humans. Imaging and microscopy technologies have revolutionized our ability to visualize and monitor cellular and molecular processes in cells and tissues, and other advances in analytical methodologies such as NMR, mass spectrometry, and array-based and microfluidics methodologies all have contributed to a rapidly growing knowledgebase about the molecular composition and function of biological systems. This knowledge, in turn, has formed the basis for our continuing research efforts to better understand and characterize the molecular and cellular mechanisms contributing to the development and progression of diseases in humans and model organisms. The general promise and primary goal of precision medicine is to identify more accurate, earlier indicators of health trajectories for individuals, the detection of early stages of disease development, revert disease development, slow disease progression, and alter health trajectories through targeted and more effective pharmacological treatments or lifestyle interventions.Unfortunately, the implementation of precision medicine approaches, whether in oncology or other fields of clinical medicine, has not kept pace with our ability to generate large-scale molecular data and information. In fact, our ability to analyze and interpret the data for translation into clinically actionable information has been challenging, and the initial promise of genomic and other molecular data as key contributors to clinical decision making has been slow to translate to clinical practice. With rapid technical advances and opportunities for more cost-efficient large-scale data generation in biomedical research, it is likely that our main challenge will continue to be the development of methods for extracting useful information from these complex, multidimensional datasets to guide clinical practice.The technological advances mentioned above have created various new fields of research, commonly referred to as “omics”. Beginning with the field of genomics, the development of novel sequencing technologies now allows the cost-effective and rapid elucidation of an entire genome and the study of all genes at once, rather than gene by gene analysis. The term “genomics” highlights this comprehensive analysis . A wholeMost often, a precision medicine approach is equated with a genomics approach. This is likely due to the fact that genomic approaches, technologies, and data were the first widespread omics data available for application in precision medicine. As a result, most early efforts in precision medicine predominantly focused on the use of genomic sequence information to diagnose patients, predict risk of individual patients for developing diseases, and to assess whether specific treatments are suitable and likely successful in individual patients. Over the past decade, genome-wide association studies, and more recently, next generation whole exome and whole genome sequencing data have provided a large set of DNA sequence variants that are associated with a plethora of diseases and traits in humans. Despite these rapidly expanding datasets, progress in identifying the specific disease-causing sequence variants and the pathophysiological mechanisms by which they affect disease development or progression has been slow. The application of polygenic risk score approaches to a range of common diseases has been one strategy to provide potentially clinically useful and actionable information from these genetic data without the need to identify individual causal sequence changes and their modes of action. However, application of these risk scores has been limited to only a few diseases. The extensive genetic variant information has also been used in pharmacogenomics to predict drug responses in individual patients. Similar to risk scores, this strategy has had limited success. Clearly, more progress is needed to effectively use available genomic information and assess benefits and limitations in risk prediction, disease diagnosis, and treatment decision making.In oncology, genomics approaches have focused on DNA sequencing to identify cancer-specific mutations, both in heritable and spontaneous cancers, and to analyze chromosomal rearrangements to characterize cancer classes or subtypes. DNA isolated from cancer cells carries a wide range of somatic and potentially inherited changes, ranging from single nucleotide polymorphisms, insertions and deletions and larger copy number variations and structural rearrangements. The total number of mutations and/or chromosomal rearrangements varies widely between tumor types, and between the same tumor types from different individuals, making it challenging to identify key functional changes that are essential for tumor formation and growth. The overall mutational pattern in human cancer has been extensively studied over the past decade and several comprehensive reviews have summarized the results ,21,22.Initial genetic oncology studies focused on the identification of inherited mutations that significantly elevate cancer risk. Early studies of families with a clustering of particular cancer types led to the identification of a number of genes and mutations that, when inherited, increase the risk for specific types of cancer. Initial examples include Lynch Syndrome, a non-polyposis colorectal cancer often caused by mutations in genes involved in DNA mismatch repair , Li-FraAdditional studies have focused on the analysis of chromosomal rearrangements and copy number variation in cancer cells. Numerous technologies, including fluorescence in-situ hybridization (for karyotypic characterization), comparative genomic hybridization , and recently next generation whole genome sequencing, allow the detailed characterization of chromosomal abnormalities predisposing to cancer development, and the identification cancer cell-specific alterations that help explain the abnormal cell growth or resistance to treatment, as in the case of the formation of fusion genes such as BCR-ABL (Philadelphia Chromosome) . Lately,Despite this tremendous progress in clinical testing for inherited forms of cancer, progress towards better understanding the underlying genetic mechanisms contributing to the majority of sporadic cancers has been more challenging. Recent advances in sequencing technologies now allow the effective analysis of individual tumors, including sequence analysis at the single cell level. The growing set of data available from these efforts have revealed that the underlying profile of somatic mutations accumulating in tumor cells is highly complex, and it has been challenging to distinguish potential ‘driver’ mutations (that are responsible for tumor formation and growth) from ‘passenger’ mutations that are phenotypically neutral. The understanding of mutational burden in tumors, however, has been used to better define the pathophysiological mechanisms contributing to tumor development and progression. Since 2005, The Cancer Genome Atlas (TCGA), an NIH-funded effort to characterize and profile the genome of 33 different tumor types and 10 rare cancers, sequenced the genomes of over 7500 samples to identify sequence variants , other DTo better characterize tumor cells and their functional abnormalities, other omics technologies have been used across the entire spectrum of human disorders. Virtually all of these approaches were also applied to tumor and cancer samples in the past several years and are beginning to contribute to a better understanding of the molecular mechanisms underlying disease processes. Similar to the chapter above summarizing the genomic approaches and technologies applied in cancer research, we will not attempt to provide a comprehensive review of all omics technologies and approaches that have been applied over the years, and how they individually have impacted and altered clinical practice. Rather, we will highlight a number of applications and discuss the resultant clinical use of the data and information, before we discuss the prevailing challenges in using omics data effectively and comprehensively in the next chapter.As sequencing and array-based technologies advanced, disease genetics research has extensively used these approaches to profile and quantitatively analyze the transcriptome of cells and tissues, and determine how changes in gene transcription in cells can be used to diagnose disorders and identify molecular mechanisms underlying the disease development and progression. These transcriptome data have also spawned an entire new approach, expression quantitative trait loci (eQTL) analysis, to identify putative functional mechanisms by which genetic sequence variation may lead to a disease by linking DNA sequence variation with changes in gene expression.To date, almost 800,000 gene expression datasets related to cancer have been deposited in the Gene Expression Omnibus (GEO) database of the National Center for Biotechnology (NCBI) of the NIH. The TCGA initiative has also used transcriptomics to provide detailed gene expression characterization of individual tumors and tissues from over 11,000 patients , and togWith a growing understanding of gene expression changes in tissues and cells, research has extensively focused on studying the regulation of gene expression. In cancer, this regulation is highly complex, with germline genetic factors, somatic mutations, and epigenetic contributors all affecting gene expression . This inAs gene expression analysis has advanced, investigations have turned to the analysis of cellular proteins, the translational ‘products’ of RNA transcripts, and the predominant mediators of cellular function. While transcriptomics allows the quantification of the immediate product of a cell’s genome at a particular time , initial large-scale studies of cellular proteomes showed a relatively low correlation between protein expression levels and corresponding mRNA expression levels . ClearlyIn cancer proteomics, the TCGA Consortium represented the first large-scale effort to profile the tumor proteome. However, the analysis was performed using reverse phase protein arrays, and was therefore limited to the targeted analysis of a few hundred proteins. However, several recent studies have used state-of-the-art mass spectrometry approaches to identify cancer-specific biomarkers in ovarian cancer , and useMetabolomics, the analysis of small molecules present in a cell, tissue, or fluid, has been the focus of biomarker discovery studies for a long time. Metabolites are often viewed as the products of cellular processes, mediated by proteins; therefore, changes in metabolites are presumed to be reflective of changes in function of the mediating enzymes and proteins. The vast majority of metabolomics analyses have focused on the analysis of plasma or serum samples from patients, often as an attempt to identify cancer or tumor-specific biomarkers that can be used in diagnosis without requiring an invasive tumor biopsy sample. However, as in most disease-related studies, determining the specificity of a characteristic change in plasma metabolites for a particular disease, or, in the case of cancer, tumor type, remains difficult, and often metabolites identified as biomarkers in one disease are also altered in other diseases.The limited studies in cancer biology have identified some putative metabolic biomarkers, such as altered carbohydrates in acute myeloid leukemia , and unsAs highlighted above, different omics datasets do not overlap extensively, and measures obtained from one omics approach are often not well correlated with data obtained by other methods. Thus, it is likely that different omics methodologies assess different parts of the complex pathophysiology of complex disease development and progression, and the analysis of just one omics subset provides a skewed, biased, and incomplete picture of the underlying biology. However, given the wide range of data that can be generated from tissue samples to characterize differences between normal and diseased cells and tissues, how does one select the most meaningful omic data types to generate (limited primarily by cost and tissue availability), and, more importantly, how does one integrate the resulting multiple omic datasets to obtain a comprehensive picture of the underlying biological processes? Essentially, there are two potential approaches to investigate multi-omics data:The first approach looks at the various analytes  in the context of known (reported) pathways and mechanisms. This approach requires prior knowledge that specific molecular pathways are central to the disease process, and a detailed knowledge and annotation of all relevant molecular pathways, with annotations and identifiers that easily link back to transcripts, proteins, metabolites, miRNAs, lncRNAs, genetic sequence variants, and DNA and histone methylation variants, to list just a few. Recent consortium efforts, such as the Encyclopedia of DNA Elements (ENCODE) have begun to link gene expression regulation to DNA sequence variation, epigenetic variation, and chromatin accessibility on a genome-wide scale in various cell types, including cancer cell lines. While this is highly informative, it remains unclear how representative this information is for other cells and tissues, such as specific tumor tissues only distantly related to the cell lines under study. Other omics data can potentially be linked using gene names/protein names, as they have been annotated in databases such as KEGG and other pathway-driven annotations. However, the further data integration becomes complicated since the ENCODE- and other regulatory data do not necessarily directly link to individual genes which in turn can be mapped to KEGG pathways. Likewise, metabolite data are only sparsely linked in the current versions of gene-centric pathway networks. This brief illustration highlights the challenges of true multi-omics data integration, and is likely the reason why most manuscripts referring to multi-omics analyses only analyze data from two or three different platforms .The second approach ignores  the existing knowledge of pathways and network interactions in cells and tissues, and looks for correlations across multiple data sets to identify molecules/analytes that are changing in a correlated manner. In principle, such an approach would be agnostic to the type of omics data used. The benefit of this approach is ability to discover novel molecules and pathways essential for the disease process. However, such an unbiased analysis very quickly becomes computationally and statistically challenging. The dataset may include RNA-Seq data on 20,000 different transcripts, but proteomics data only on 2,000 proteins. Furthermore, some data are generated using platforms that exhaustively analyze and quantify the molecules of interest , some may be unbiased, but only identify and quantify the most abundant molecules , and yet other methodologies may use targeted approaches to investigate samples . Finally, a complete multi-omics dataset may include over 100,000 analytes, yet they are likely to be measured in only a limited number of tissue samples (100 tumor biopsies), or potentially even in different samples from the same patient . Analytical tools have been suggested for these types of complex datasets, such as clustering approaches , or weigNumerous recent reviews and opinion pieces have suggested that the field of precision oncology will greatly benefit from a multi-omics analytical approach ,78,79. IProbably one of the most ambitious efforts to assess the opportunities and challenges in using integrated multi-omics data for health assessment and prediction comes from the integrated personal omics profiling (iPOP) project . InitialOverall, this short summary highlights that the concept of precision medicine is more than the use of genetic variant information to inform clinical practice and the fact that the use multi-omics approaches to achieve precision medicine in the clinic is extremely valuable but still in its infancy. Not only in precision oncology, but in a wide range of human disease-related research, we are just beginning to generate comprehensive, unbiased data that are truly multi-omic. Only with the generation of these different omic datasets from the same biological samples will we be able to develop the necessary analytical  and annotation tools that will help us interpret these complex datasets, and help extract biological and clinically relevant information. The Trans-Omics for Precision Medicine (TOPMED) Initiative of the NHLBI is one example of a large-scale effort that is beginning to generate more comprehensive omics data for a wide range of study cohorts, based on already existing studies and sample material. Generating multi-omics data is expensive and time-consuming, and the usefulness of the resulting data critically depends on the availability of suitable tissue samples and biopsy material collected in a way that allows the effective analysis of tissue transcriptome, epigenome, proteome, and metabolome. Until recently, biopsy samples were mainly collected for transcriptome analysis or mutation discovery, and accordingly, samples were often collected in buffers that stabilized RNA and DNA, but essentially render the sample material unsuitable for protein or metabolite profiling. Future studies will need to address this so that we can generate the necessary comprehensive multi-omics data and begin to untangle the complex biological mechanisms that control tumor formation and progression, the development of resistance to treatment, and the risk of recurrence. We will need to focus on the characterization of integrated multi-omics signatures and mechanisms rather than small sets of putative diagnostic biomarkers that are currently being marketed to clinicians if we hope to truly advance precision medicine and precision oncology using multi-omics approaches.


The main neurovascular unit of the Blood Brain Barrier (BBB) consists of a cellular component, which includes endothelial cells, astrocytes, pericytes, microglia, neurons, and oligodendrocytes as well as a non-cellular component resulting from the extracellular matrix. The endothelial cells are the major vital components of the BBB able to preserve the brain homeostasis. These cells are situated along the demarcation line between the bloodstream and the brain. Therefore, an alteration or the progressive disruption of the endothelial layer may clearly impair the brain homeostasis. The proper functioning of the brain endothelial cells is generally ensured by two elements: (1) the presence of junction proteins and (2) the preservation of a specific polarity involving an apical-luminal and a basolateral-abluminal membrane. This review intends to identify the molecular mechanisms underlying BBB function and their changes occurring in early stages of neurodegenerative processes in order to develop novel therapeutic strategies aimed to counteract neurodegenerative disorders. To this purpose, the blood-brain barrier (BBB) represents a physical and functional barrier able to provide all these functions, which separates the CNS from systemic circulation. The Central Nervous System (CNS) is the most complex and highly organized system in the human body and its optimal functional state depends on the maintenance of stable biochemical conditions. In fact, to better perform their functions, neurons require a constant balance among various chemical  and electrical signals aimed to sustain the proper intra-cellular and inter-cellular communication. In particular, a constant intracellular and extracellular concentrations of ions ,” “Adherens Junctions (AJ),” and “gap junctions.” Gap junctions are responsible for intercellular communication and can be lacking while TJ and AJ proteins control the permeability of the endothelium . Figure The TJ complex is composed of three types of integral membrane proteins: (a) claudins, (b) occludins, and (c) junctional adhesion molecules (JAMs) to which some auxiliary cytoplasmic proteins such as ZO-1, ZO-2, ZO-3, and cingulins are added. The TJ complex is located in the apical region of the endothelial cells and its proteins act as an inter-endothelial demarcation between the apical and the basolateral side of the cell, which shows an asymmetric distribution of the membrane components . The junctional proteins are located at the lateral membrane of the adjacent endothelial cells and, on the basis of their reciprocal interaction, are able to seal the intercellular gaps while the auxiliary cytoplasmic proteins establish a connection between the junction proteins and the intracellular cytoskeletal proteins. This is the pre-requisite to ensure the functional and structural integrity of the endothelium, which maintains BBB selective permeability and counteracts an excessive infiltration of immunocompetent cells in the brain tissue . The family of claudins is composed of 26 isoforms even though the most common ones are claudin 1, claudin 3, claudin 5, and claudin 12 . The proHuman claudin-1 have 211 amino acids and its molecular weight amounts to 22,743 kDa. Moreover, it establishes homophilic and heterophilic interactions with other claudins  belonging to the adjacent cells. Human claudin-3 consists of 220 amino acids and its molecular weight corresponds to 23,318 kDa. It is significantly involved in embryogenesis and postnatal development . Human cHuman occludins have a larger size than claudins. In fact, they consist of 522 amino acids and their molecular weight is 65 kDa. Seven occludin isoforms have been identified, which contain 11 tyrosine and 19 glycine residues responsible for the structural flexibility . OccludiOccludins possess multiple phosphorylation sites corresponding to the serine and threonine residues. Phosphorylation is directly involved both in the control of their combination with the cell membrane and in their function . MoreoveLastly, cryptic ‘self’ tight junction antigens involving occludins can trigger an autoimmune response, which contribute to the neuro-inflammatory diseases such as Alzheimer’s disease and Parkinson’s pathology hallmarks .The third class of proteins belonging to the TJ complex is represented by the Junctional Adhesion Molecules (JAMs) including three proteins  of 40 kDa molecular weight. Recently, JAMs have been reported to be an immunoglobulin superfamily characterized by a single transmembrane domain with the intracellular section containing disulfide bridges. Apparently, JAMs proteins are not involved in the formation of the TJ complex but do take part in the assembly of the TJ components as well as in the adjustment of the complex responsible for endothelial polarization .In addition to the transmembrane TJ components, some auxiliary cytoplasmic proteins have been connected to the TJ complex and contribute in preserving the integrity of the brain endothelium. A special emphasis has been given to the members of the membrane-associate guanylate kinase (MAGUK) family, which are characterized by three PDZ, one SH3, and guanylkinase-like (GUK) domains. Among MAGUKs, the ZO proteins  interact with the C-terminus of claudins and the JAM components interact through a PDZ domain ,24 and wThe AJ complex basically includes cadherins, which contribute to the connection with the proteins of the AJ complex in the adjacent cells by using a calcium-dependent mechanism. Conversely, the intracellular domains bind to cytoskeletal structures . The AJ The polarity of the endothelial cells plays a key role in maintaining the integrity of the BBB, which is involved in counteracting the access of polar compounds, pathogens, and immune cells to the brain tissue . Figure The brain endothelium polarity is also crucial for the preservation of the BBB integrity. In fact, it controls the expression and function of the intercellular junction proteins . In turnThe endothelial polarity process is ensured by protein complexes such as Par, Crumbs, and Scribble, which are responsible for the polarity control . The memThe Crumbs complex includes trans-membrane proteins oriented towards the TJs. The main members of this complex are PALS1, PATJ, which are involved in the reduction of the para-cellular permeability . ScribblNeurodegeneration is often characterized by an altered connection between TJs and AJs, which leads to a loss of the endothelial polarity and the impairment of the BBB integrity. In particular, the altered expression of Junction proteins can affect BBB in aging, in pathological states such as neurodegenerative diseases, and under dysfunction of physiological processes including an altered sleep-wake cycle and the equilibrium of gut microbiota. It has been demonstrated that numerous neurodegenerative diseases  and cancer as well as pathogenic infections and other pathological conditions, which are connected to the overproduction of both inflammatory cytokines and reactive oxygen species, can lead to an endothelial alteration at the BBB level and can be attributed to the disorganization and/or destruction of the junction proteins . These eThe chronic reduction of sleep hours has been linked to a lower expression of the TJ complex proteins, a limited glucose uptake, and the resulting increase in the permeability to sodium. However, these altered TJ protein levels can be reverted by re-establishing the sleep-wake cycle . An alteration of the gut microbiota may be associated with lower levels of claudin-5 and occludins as well as with an increased BBB permeability even though the related mechanisms require further investigation . Despite growing evidence showing that the disassembly of the TJ and AJ complexes results in a higher BBB permeability, the alteration of the TJ complex is the main factor underlying the impairment of the endothelial cells. In particular, many mechanisms able to affect TJs are already known including the processes of phosphorylation in serine-threonine or tyrosine residues, the altered degradation, and the translocation of junction proteins as well as their down-regulation ,48. DephAlthough protein kinase C (PKC) signaling has previously been related to the destruction of the BBB mostly during hypoxia , its invThe alteration of the BBB permeability also involves the RhoA GTPase protein belonging to the G-protein family. In fact, it has been demonstrated that the activation of this protein causes cytoskeletal rearrangements during cell proliferation and migration besides the disorganization of the AJ complex . FurtherIn a mouse model of stroke and traumatic brain injury (TBI), the permeabilization of BBB develops following a “bi-phasic” opening of BBB in spite of an adequate reperfusion aimed to support the damaged neuronal tissue and to restore the normal bloodstream . The devThe release of reactive oxygen species (ROS) by neutrophils induces the other cells to produce a higher amount of cytokines, which attracts a greater concentration of leukocytes from the peripheral areas. Therefore, this prolongs the inflammatory cascade after an ischemic stroke and reduces BBB integrity . This evidence was further confirmed by other studies showing structural alterations of the proteins belonging to the TJ complex, a higher transcytosis/endocytosis ratio, and a lower expression of occludins and ZO-1 after 48 to 58 hours from the ischemic insult. Conversely, during the earliest periods, a greater integrity of the TJ complex was observed .ALS is a neurodegenerative disease that involves a BBB alteration. In fact, in a mouse model of ALS, the motor neuron degeneration was characterized by a lower expression of occludins and ZO-1 at the molecular level , which wMultiple sclerosis is a neuro-inflammatory disease characterized by the infiltration of auto-reactive T-lymphocytes in the central nervous system and is the most widespread autoimmune disease in the Western world. Therefore, this disease clearly results from the BBB breakage and the resulting cell damage. The association of the dephosphorylation of occludins with the onset of various clinical symptoms has been proven at the molecular level , which sRecently, it has been discovered that patients suffering from a mild or moderate Alzheimer’s disease featured BBB alterations . The accThe alteration of the BBB endothelium also originates from the diffusion of pathogens such as bacteria and viruses, which may affect the central nervous system. Bacteria cross BBB through different mechanisms. In particular, bacteria can pass the BBB, which colonizes lymphocytes or uses the leukocyte transendothelial migration and releases lipopolysaccharides (LPS), toxins, cytokines, or inflammatory molecules . On the The virus-mediated neuronal alterations affect the BBB structure because of the destruction of the TJ complex. For example, the West Nile virus (WNV) leads to a significant loss of TJ proteins . HIV patients have shown to develop neurological complications due to extensive neuronal damage such as cognitive and motor deficits . Recent The BBB endothelial cells are also involved in the transport and sorting of the nutrients by the blood to the central nervous system. The passage of metabolites is controlled by an elaborate highly restrictive junction complex acting between endothelial cells . This isThe transport type varies according to the chemical composition of the substance to be transported ,81. In fThe facilitated transport mediated by carriers favoring the passage of small hydrophilic molecules  is recogGlucose is the main energy source for the brain tissue and its intake is catalyzed by the facilitated glucose transporters  and the sodium/glucose cotransporters . Among them, the most common transporter in mammals is GLUT1, which is expressed both in the luminal and in the abluminal endothelial membrane . The funThe brain energy level is also ensured by creatine and choline. Creatine is responsible for a higher production of ATP and its transport in the brain is mediated by the specific SLC6A8 sodium and chlorine dependent transporter . CholineThe transport of amino acid across the BBB is catalyzed by facilitated diffusion carriers. Among them, specialized proteins (SLCs) are able to promote the transport of glutamate, aspartate, GABA, and glycine ,91. 2+, Zn 2+, Mn2+, Fe 2+, Cd2+, Co2+, and Ni2+) [Furthermore, SLC carriers  are responsible for the transport of nucleosides , nucleoside triphosphate , nucleobases  , water-snd Ni2+) . Lastly, the water passage must be assessed as well since its control is crucial for the preservation of the ionic concentration and the proper brain and BBB functioning ,95. The The first form of the active transport across the BBB involves the ABC transporters (ATP-binding cassette) which, through the hydrolysis of the ATP molecule used as an energy source, ensure the entry and exit of many organic compounds through the membranes ,98. The Some ABC subfamilies are involved in the transport of lipids, proteins, metals, and in drug resistance processes . Recent The last type of active transport examined in this study is the transcytosis, which is based on the bidirectional transport of clathrin-coated vesicles and contains nutrients and the relating carriers as well as ligand-receptor complexes, membrane proteins, bacteria, and viruses ,105. The alteration of the described transport mechanisms across BBB have detrimental effects on neurons, which lead to the onset of numerous neurodegenerative diseases . For example, major disorders including epilepsy, hypotonia, spasticity, ataxia, and cognitive disorders have been associated with GLUT1 impairment ,108. MorMany experimental mouse models presenting dysfunctional excitatory amino acid transporters at the BBB showed a 50% mortality rate of the animals involved in the study . PatientThe alteration of the SLC transporter of thiamine has been related to encephalopathy, dysarthria, dysphagia, stiffness, confused state, and even death. Moreover, the early onset of the Leigh syndrome together with progressive neurodegenerative phenomena and subsequent SLC transporter dysfunction have been detected . A decrease in the iron levels caused by a defect in metal transport in the brain results in cognitive and motor disorders while its accumulation can induce oxidative stress, which induces the onset of chronic neurodegenerative diseases such as Parkinson’s disease, Huntington’s disease, and Alzheimer’s disease . A mutatThe expression of the ABC transporters is largely reduced in the presence of some neurological diseases such as Alzheimer’s disease, Parkinson’s disease, epilepsy, and amyotrophic lateral sclerosis ,117,118.Lastly, an alteration of transcytosis at the BBB endothelium also causes evident neurological impairments. In fact, there is a correlation between the alteration of transcytosis and ischemia-related brain damage ,120,121.Endothelial cells are the main component of the blood-brain barrier and their compromised function has been associated with numerous diseases of the CNS including neurodegenerative and neuro-inflammatory disorders. The main mechanisms that may reduce the integrity of the BBB are ones that disrupt AJ and TJ complexes such as through inflammatory processes and a dysfunction in transport systems. As a consequence, the identification of mechanisms underlying the impairment of endothelial balance represents a priority for the development of new therapeutic strategies aimed to prevent BBB breakdown and the development of several neurodegenerative diseases.


Descriptive, quantitative andmultivariate statistics were applied.descriptive cross-sectional study in a sample of 235 nursing professionalsand physicians who worked in four hospital emergency services. The MaslachBurnout Inventory, the General Health Questionnaire and thethe dimension of depersonalization, avoidance-centered coping and being aphysician were related to the presence of somatic symptoms, anxiety, socialdysfunction and depression. Increased professional experience was associatedwith greater social dysfunction among health personnel and increased numberof patients was related to depressive symptoms among healthprofessionals.the dimensions of emotional exhaustion and depersonalization,avoidance-centered coping, being a physician and a daily smoker increase therisk of a psychiatric case. The practice of daily physical exercise is aprotective factor. In this sense, the number of countries reporting occupationaldiseases, especially mental changes such as neurosis, paranoia, depression, anxiety,insomnia or fatigue, is growing.The need to include mental health in the priorities of public health programs hasbeen recognized for several decades. The promotion of mental health has a specialrelevance in the work environment, since it is an important factor in thedevelopment of physical and mental problems, in an often stressful work environment that implies, among others, themanagement of diagnostic and therapeutic uncertainties, which can produceburnout.In the health field, the prevalence of psychiatric morbidity in health professionalsworking in the hospital emergency service is 36.8%. Emotional exhaustion causes a decrease or loss of emotional resources,depersonalization leads to the development of negative attitudes toward patients,and lack of personal fulfillment is characterized by decreased feelings ofcompetence and achievement at work.Burnout is defined as a three-dimensional psychological syndrome consisting ofemotional exhaustion, depersonalization, and personal fulfillment that occurs inresponse to chronic work stress. Thus, a growing number of studies indicate that women increase therisk of suffering burnout based on the double presence of women at home and at work,lower wages, or greater at work.The incidence of burnout has increased in recent years and numerous studies have beencarried out with the aim of establishing the causes and factors associated withit(–). In the nursing team, high levels of burnout produce a higher incidenceof musculoskeletal disorders, occupational injuries, absenteeism, jobdissatisfaction, as well as abuse of alcohol and other drugs. In addition, they negatively affect, among others, the quality of carereceived by patients and the mental health of nursing professionals, which can causedepression, anxiety, low self-esteem, or feelings of guilt.The highest rates of burnout correspond to professionals working in the emergencydepartment compared to the other specialties. Coping is the process by which the individual, by cognitive, emotionalor behavioral efforts, manages, controls, or reduces the demands of theindividual-environment that have been assessed as stressful. There are two styles of great coping. On the one hand, there is theactive or adaptive coping, used when stressful conditions are evaluated by theindividual as subject to change, modification or elimination using strategies suchas the search for problem solving or positive re-reading. On the other hand, thereis the passive or maladaptive coping used when stress conditions are assessed aspermanent or non-modifiable. This type of coping includes behavioral strategies ofescape or evasion, and behavioral and cognitive distancing or selective attention inorder to reduce emotional problems. The use of a particular strategy depends on the previous level ofpsychological and family adaptation of the individual, and on available socialresources.One factor that may moderate the negative impact of burnout on the physical andpsychological well-being of health professionals is their coping style or burnout-coping strategies, or mental health-coping strategies in emergency care professionals. Both individual and organizationalconsequences may arise from burnout and the response generated by professionals insimilar situations or conditions is different. In view of this, it is necessary todeepen the relationships between burnout, coping strategies, and mental healthtogether as a preliminary step towards the implementation of prevention andintervention programs that are useful in the promotion and implementation of newcoping strategies with a comprehensive approach at the individual, social andorganizational level and that allow adequate levels of mental health in theemergency hospital services.Several studies have focused on analyzing the binomials of burnout-mentalhealthThe objectives of this study are to evaluate the influence exercised by burnout andcoping strategies used by emergency care professionals in their mental health statusand to determine the sociodemographic and labor characteristics.A descriptive, cross-sectional and multicenter study was carried out from March toDecember 2016, in the emergency department of four hospitals in the AutonomousCommunity of Andalusia (Spain). Two hospitals were public  and twowere private hospitals . Data on the total number of bedsand health personnel working in the emergency rooms were provided to the researchersby the nursing managers of the different hospitals, who were chosen by incidentalsampling. The study population consisted of all medical and nursing professionalsfrom the emergency services of these hospitals.Active workers were included during data collection and those whose time of work inthe hospital emergency service was equal to or greater than one year. Internspecialists and health professionals treated with antidepressants and/or anxiolyticswere excluded., assuming that the population was 478 individuals. The sample size wascalculated using the Epidat 4.0 program and was based on presuming the lowestadvantageous prevalence.A sample of 235 subjects with a confidence level of 95%, an absolute precision of 4%and a psychiatric morbidity of 25.50% was setThree validated, calibrated and self-administered questionnaires were used, as wellas another one that included sociodemographic variables: gender , age(years), marital status  daily practice ofphysical exercise  and daily tobacco consumption , as well aslabor variables: professional category , type of contract , time of work in the hospital emergency service (years),professional experience (years), and number of patients attended daily.. The MBI evaluates three dimensions of burnout: emotional exhaustion,depersonalization, and personal fulfillment. The questionnaire consists of 22 items,with a Likert-type response format, in which professionals indicate the frequency ofstated situations from zero (never) to six points (daily).The burnout evaluation was performed through the Maslach Burnout Inventory (MBI) inits adapted version for the Spanish language. Low levels of the dimensions emotional exhaustion anddepersonalization and high personal fulfillment are indicative of absence ofburnout. On the other hand, high burnout is characterized by high levels ofemotional exhaustion and depersonalization and low levels of personal fulfillment.Average level of burnout is found in the rest of the cases.To determine the score of each dimension, the scores of the items belonging to eachdimension are added. The emotional exhaustion dimension is composed of nine items,with a minimum total score of zero point and maximum of 54 points. Thedepersonalization dimension is composed of five items, the total score ranging fromzero to 30 points. The personal fulfillment dimension consists of eight items andthe total score varies between 0 and 48 points. The higher the score obtained in thedimensions of emotional exhaustion and depersonalization, the worse the level ofburnout, while the interpretation of the personal fulfillment dimension is thereverse. Dimensions were categorized into low, medium and high level, taking intoaccount the following cutoff points: emotional fatigue , depersonalization  and personal achievement  to assess the subjects' mental health. It consists of 28 items dividedinto four subscales of seven items: somatic symptoms , anxiety,social dysfunction  and depression . The subscales represent dimensions of thesymptomatology, therefore do not correspond to psychiatric diagnoses. Each item isevaluated using a scale of four possible responses, ranging from zero  to three . For the evaluation of the results, thebimodal response scale was used, in which different positions share a score. In thisway, possible errors due to the choice of extreme or central responses are avoided.Thus, zero is scored if either of the first two options is answered, and one isscored if either of the latter two is answered (0011). For each of the subscales,the score can vary from zero (absence of symptoms) to seven (maximum frequency ofsymptoms).The General Health Questionnaire (GHQ-28) was applied in its validated version to theSpanish languageScores ≤6 show absence of metal changes, while scores equal to 7 are indicative ofthe presence of a probable psychiatric case.Inventario breve deafrontamiento - COPE 28, adapted to the Spanish language. The questionnaire was used in a dispositional manner, and the subjectsresponded by referring to how they deal with stressful situations. The questionnaireconsists of 28 items with four response options on a Likert scale ranging from zero(I do not do any of this) to three (I do this very often). The items are groupedinto fourteen scales of two items each. These scales represent three types ofcoping: problem-centered coping , emotion-focused coping and avoidance-focusedcoping . In order to obtain thetotal score of the coping types, the scores of the items that make up each of themare added and divided by the number of items that make up each type of coping. Thus,the types of coping vary between 0 and 3 points. High scores indicate greater use ofthe strategy.The subjects' coping was measured with the The questionnaires were handed out to each participant at the beginning of the workshift and returned directly to the researchers at the end of the work shift.Together with the questionnaires, an informative letter was attached, detailing theobjectives of the study, the form of collaboration of the subjects, as well as thevoluntary and anonymous nature of the said participation, and an explicit requestfor collaboration in which the health professional gave his/her consent toparticipate in the study.The study was approved by the Research Ethics Committee of the Reina Sofia UniversityHospital of Córdoba, Spain  and by themanagers of the emergency service of participating centers, in accordance with theprinciples of Helsinki.2 was usedto evaluate the adequacy of adjustment. The gross and adjusted values of the ßcoefficient were determined. In the binary logistic regression model, the likelihoodratio test and Nagelkerke R2 were used to determine the quality ofadjustment. The area under the Receiver Operating Characteristic (ROC) curve wascalculated to determine which explanatory variables are most associated with theprobability of establishing a psychiatric case. Gross and adjusted Odds Ratio (OR)values were determined. Values p <0.05 were considered significant. Forstatistical analysis, the G-Stat program, version 2, was used.For the analysis of the qualitative variables, a frequency table was used to measurethe mean and standard deviation. To establish possible relationships between thequalitative variables, the Chi-square test or the Fisher's exact test were use, andthe Student's t-test and analysis of variance were applied for the quantitativevariables. The normal distribution of the data was verified by theKolmogorov-Smirnov test. In cases where the normality hypotheses were not met,non-parametric tests  were applied. For thecorrelation of variables, the Pearson or Spearman correlation coefficient wascalculated according to the applicability conditions. Four multiple linearregression models were performed using the reverse variable selection method, onefor each GHQ-28 subscale. The dependent variables of each model were somaticsymptoms, anxiety, social dysfunction and depression. In addition, a binary logisticregression model was performed, whose dependent variable was the presence/absence ofprobable psychiatric cases detected by GHQ-28. The independent variables included inall models were gender, age, marital status, daily practice of physical activity,daily tobacco consumption, professional category, type of contract, length ofservice in the hospital, professional experience, number of patients attended daily,emotional exhaustion, depersonalization, personal fulfillment, problem-centeredcoping, emotion-centered coping, and avoidance-centered coping. In each model, bymeans of the Wald statistic, the variables with p ≥ 0.15 were eliminated one by one.The continuous variables scale was evaluated by the Box-Tidwell test. The possibleinteractions between all the variables were studied. The variables with significancegreater than 0.05 were studied as possible confounding factors, considering them asif the percentage variation of the coefficients was greater than 15%. In themultiple linear regression models, the residue normality was verified by theKolmogorov-Smirnov test. We did not consider the existence of collinearity problemsamong the independent variables if the factor of increase in the variance was lessthan or equal to 10. As a diagnostic test of extreme cases, the analysis of studentresidues was used. The adjusted coefficient of determination RA total of 235 professionals participated in the study. The female populationconstituted the predominant population, with 76.2% . The meaThe bivariate analysis  found aThe conditions of the multiple linear regression model of residual normality weremet, no collinearity was found between the independent variables and no extremevalue was found for subscales of somatic symptoms and anxiety. The frequency ofsomatic symptoms increased 0.02 points for each increase in the depersonalizationdimension score (p = 0.01), 2 points for each increase of the avoidance-centeredcoping score  and 0.3 points among the medical staff in relation tonursing professionals (p = 0.02). The frequency of anxiety symptoms increased by 0.1points for each increase in the depersonalization dimension score (p = 0.01),doubling for each increase in the avoidance-centered coping score (p = 0.001) andincreased 0.7 points among the medical staff in relation to nursing professionals (p= 0.001) .The conditions of the multiple linear regression model of residual normality,non-collinearity between the independent variables and non-existence of extremevalues for the subscales of social dysfunction and depression were met. Thefrequency of symptoms of social dysfunction decreased by 1 point for each increasein frequency of problem-focused coping score (p = 0.002), increased by 0.5 pointsfor each year of work experience , increased by 2 points for eachincrease in the avoidance-centered coping score (p = 0.001), and increased by 0.5points among the medical staff in relation to nursing professionals (p = 0.03). Inaddition, the frequency of depressive symptoms increased by 0.2 points for eachincrease in avoidance-focused coping frequency (p = 0.03), increasing by 0.4 pointsfor each patient attended daily by professionals (p = 0.04) and doubled among themedical staff in relation to nursing professionals (p = 0.001) .The risk of having a probable psychiatric case was determined by increased emotionalexhaustion , depersonalization , avoidance-centered coping , daily consumption oftobacco  and being a physician , while daily practice of exercise was a protective factor  .In this study, on the one hand, the variables related to the presence of somaticsymptoms in health professionals were on the dimension of depersonalization,avoidance-centered coping and being a physician. These last two variables were alsorelated to the symptomatology of anxiety, social dysfunction and depression. Inaddition, the depersonalization dimension was related to anxiety; professionalexperience and problem-centered coping were related to social dysfunction and to thenumber of patients treated daily with depressive symptomatology. On the other hand,the risk of being a psychiatric case was determined by the level of emotionalexhaustion, depersonalization, the use of avoidance-centered coping, dailyconsumption of tobacco and being a physician, while daily physical exercise was aprotective factor.. Although the level of burnout was average, according to a recentstudy, the highest prevalence rate of burnout was found in the hospitalemergency ward (71%).The mean burnout scores placed the sample at a low level of emotional exhaustion anda means of depersonalization and personal fulfillment. These findings are similar tothose obtained in previous studies. The problem-centered coping was the most commonly used strategy, whichcould explain the relative low morbidity found. This finding is consistent with thatobtained in another study.The proportion of possible psychiatric cases among the health professionals studiedwas 32.3%, similar to that obtained in another study(–), having the dimension of emotional exhaustion as the strongestlink(–).The dimensions of emotional exhaustion and depersonalization increased the risk ofbeing a psychiatric case among health professionals. Depersonalization, moreover,was related to the presence of somatic symptoms and anxiety. However, the dimensionof personal fulfillment has been left out of these relationships. Some authors havehighlighted the relationship between emotional exhaustion and depersonalization andthe appearance of symptoms related to a worse level of mental health. However, this type of coping may be the best option for emergencypersonnel working outside the hospital environment, especially when the eventoccurs, in order to avoid emotional involvement. In addition, a negative relationship was found between the use of theproblem-focused coping strategy and social dysfunction. Evidence indicates thatthere is a significant relationship between a good level of mental health and theuse of the problem-focused coping strategy. On the other hand, and morespecifically, those who have trouble maintaining or initiating a relationship withothers  tend to experience inadequate emotional growth, loneliness,depression and do not get used to using types of active coping.The avoidance-centered coping strategy was related to somatic symptomatology,anxiety, social and depressive dysfunction in professionals. In addition, itincreased the risk of being a psychiatric case. These findings are in agreement withthe results of another study, several studies conclude that in the emergency service, medicalpersonnel are more likely to report justified psychological adverse outcomes basedon their responsibility, while nursing professionals point to a higher level of jobdissatisfaction. Although nursing professionals do not present mental changes, theyappear to be influenced by coping strategies. In this sense, the person-environmentadjustment can moderate the perceived stress, the work-family conflict and the levelof mental health. In addition, clinical supervision seems to mediate stress andmental health in this group.Regarding the sociodemographic and labor characteristics related to mental healthstatus, it was found that medical personnel had a higher risk of being a psychiatriccase than nursing professionals. In addition, being a physician was related to thefour subscales that make up the GHQ-28 . Although it is true that nursing is considered one ofthe most stressful occupations, which may increase the risk of suffering psychiatricdisorders. This finding can be explained by two facts. On the one hand, theevidence shows the positive relationship between work experience and the burnoutlevel. On the other hand, the presence of symptoms associated with worsedaily functioning (ability to concentrate or enjoy activities) could be related toan increase in the burnout level.The present study found a positive relationship between professional experience andthe social dysfunction scale of GHQ-28, contrary to that found in otherresearch. Similarly, in emergencies, the constant flow of patients cared for bynursing staff is considered a factor associated with burnout in thisgroup.In addition, it was found that the daily increase in the number of patients seen inthe emergency department was related to the greater presence of depressive symptomsmanifested by professionals. The literature has shown that increasing numbers ofpatients and of professionals' overload increase the risk of depressive symptomsamong health professionals and that depression and anxiety rates are higher among nicotinedependents.The risk of being a psychiatric case was reduced in professionals who practiced dailyexercise and increased among those who consumed tobacco daily. Evidence indicatesthat physical exercise attenuates the anxious response to emotionalstimuliThe limitations of this study include a possible selection bias in the studypopulation, since it is subject to the professionals' degree of interest inparticipating in the study. In addition, the results point to associations, but donot allow establishing cause and effect relationships. Although Andalusia is arepresentative area of the health system, it would also be interesting to considerprofessionals from other geographical locations.This work highlights the need to continue with lines of research that use morecomplex projects to determine the role played by burnout and the passive coping inthe mental health of health professionals. Thus, health care weaknesses could bedetermined and mental health control increased, thereby reducing the negativeconsequences that result from an inadequate level for the system and the user.Nursing professionals do not present mental changes. Increased levels of emotionalexhaustion, depersonalization, avoidance-centered coping, being a physician, andconsuming tobacco daily increase the risk of becoming a psychiatric case. In turn,the practice of daily physical exercise is a protective factor. The variablespositively related to psychological somatic symptomatology and anxiety are thedimension of depersonalization, the use of avoidance-centered coping strategies andthe being a physician. Social dysfunction is directly associated with the fact ofbeing a physician, with the use of coping focused on avoidance and with professionalexperience, and inversely related to the use of problem-centered coping strategies.Finally, the presence of depressive symptoms is related to the use ofavoidance-centered coping strategies, being a physician and increased number ofpatients attended daily.


Lipid accumulation in the arterial wall is a crucial event in the development of atherosclerotic lesions. Circulating low-density lipoprotein (LDL) is the major source of lipids that accumulate in the atherosclerotic plaques. It was discovered that not all LDL is atherogenic. In the blood plasma of atherosclerotic patients, LDL particles are the subject of multiple enzymatic and non-enzymatic modifications that determine their atherogenicity. Desialylation is the primary and the most important atherogenic LDL modification followed by a cascade of other modifications that also increase blood atherogenicity. The enzyme trans-sialidase is responsible for the desialylation of LDL, therefore, its activity plays an important role in atherosclerosis development. Moreover, circulating modified LDL is associated with immune complexes that also have a strong atherogenic potential. Moreover, it was shown that antibodies to modified LDL are also atherogenic. The properties of modified LDL were described, and the strong evidence indicating that it is capable of inducing intracellular accumulation of lipids was presented. The accumulated evidence indicated that the molecular properties of modified LDL, including LDL-containing immune complexes can serve as the prognostic/diagnostic biomarkers and molecular targets for the development of anti-atherosclerotic drugs. Cardiovascular diseases (CVDs) are responsible for the high mortality and morbidity rates among adults worldwide posing a major socioeconomic burden not only on the health care system of a country but also on the whole national economic growth. The WHO World Heart Day 2017) has declared that the death toll in 2016 due to CVDs was an estimated 17.9 million people representing 31% of all causes of deaths in the world [7 has decAtherosclerosis is the main underlying cause of life-threatening CVDs. Relying on the population-based observational studies, it was established that the high incidence of atherosclerosis is prevalent among older adults in societies that adopt the Western pattern of diet and lifestyle ,5,6. In Furthermore, there is strong evidence that atherosclerosis affects young people and its prevalence and extent increase with age. Numerous studies reported that the subclinical form of atherosclerosis is frequently present in a large population of young adults in association with the presence of atherosclerosis risk factors ,12,13,14Human atherosclerosis is a complex systemic inflammatory disorder characterized by the interplay between several different moieties, including various lipids, enzymes, endothelial cells, cytokines, and circulating mononuclear cells. Such interactions lead to the thickening of the arterial wall due to lipid accumulation in the intimal layer, endothelial dysfunction, and inflammatory and fibroproliferative responses resulting in vascular proliferation, alterations in the extracellular matrix, and the formation of atherosclerotic plaques. The formation of atherosclerotic lesions takes place at specific arterial regions (branching sites), where low and oscillatory endothelial shear stress occurs . AtherosSubendothelial lipid accumulation plays a crucial role in the development of atherosclerotic lesions in the arterial cells. The extra- and intracellular lipid deposition predominantly of cholesterol esters leading to the formation of foam cells in the arterial intima is not only one of the earliest manifestations of atherosclerosis  but also the triggering event of the onset of atherosclerotic lesion development . The celTherefore, in the study of atherogenesis, the early event of the atherosclerotic process is particularly important. In this regard, the mechanisms of atherogenic modifications of low-density lipoprotein (LDL) particles in the blood of atherosclerotic patients attracted special attention. In this review, we will discuss the molecular properties of circulating modified low-density lipoprotein that trigger atherogenesis, highlighting the importance of its desialylation.The hypothesis of cholesterol retention in the arterial cells linked to the high levels of total cholesterol in the blood that trigger initiation and further progression of atherosclerosis was proposed by Nikolai Anitschkow over 100 years ago. However, later it was established that lipid deposition in the arterial intima is not associated with the total cholesterol levels but with the high levels of the atherogenic LDL cholesterol ,22,23. IFollowing the lipid theory of atherosclerosis, LDL is the main transporter of serum cholesterol to the target vascular cells , therefoRicinus communis (RCA120), which has a high affinity to terminal galactose [Sialic acid is an important element of native LDL that represents the terminal carbohydrate of biantennary sugar chains in apolipoprotein B (apoB) and carbohydrate chains in gangliosides. Galactose, which is the monosaccharide residue preceding sialic acid in the carbohydrate chain, becomes terminal and exposed externally after the desialylation. This was used to isolate the desialylated LDL fraction from the total LDL using agglutinin alactose ,32. Thisalactose . In thisalactose . Interesalactose . Moreovealactose ,28.The sequence of multiple modifications of LDL particles was observed in the ex vivo experiments . It was Remarkably, despite a large number of the experiments studying the role of oxidized LDL (oxLDL) in atherogenesis, artificially generated in vitro species of oxLDL remain undetectable in the blood. In fact, circulating mmLDL particles were found to exhibit signs of oxidation , howeverThus, as compared to native LDL, desialylated LDL particles have a low content of sialic acid; they are smaller, denser, and more electronegative; they have increased lipid peroxidation; and contain more triglycerides and fatty acids . NotablyFurthermore, mmLDL is prone to a spontaneous aggregation and formation of complexes that further increases its atherogenicity. Thus, another LDL modification that is an essential condition for intracellular cholesterol accumulation is the formation of large highly atherogenic LDL-containing complexes, i.e., self-associates. It was noticed that without the formation of self-associates, even modified LDL does not cause the intracellular accumulation of lipids, hence it is not atherogenic . The uptIn addition, LDL retained in the arterial wall can be also affected by enzymatic modifications since the following enzymes are hyperexpressed in the atherosclerotic plaque microenvironment: Cholesterol esterase (CEase), sphingomyelinase (SMase) or secretary phospholipase A2 (sPLA2) or proteases  . The maiRelying on the above-described studies, it is possible to conclude that the circulating LDL of atherosclerotic patients sustains a cascade of consecutive modifications, such as desialylation, decrease in lipid content, reduction of the particle size, increase of its density and negative charge, lipid peroxidation, and the ability to aggregate that are indicative that it is atherogenic. Other non-enzymatic and enzymatic modifications can also affect circulating lipoproteins, therefore, also contributing to lipid accumulation in the arterial wall. It has to be stressed that desialylation is the most likely primary atherogenic modification of LDL, and hence, the most important modification in the initiation and development of atherogenesis. The subsequent series of LDL modifications are likely to represent a chain of multiple modifications that enhance its atherogenicity. The importance of LDL desialylation, in terms of inducing blood atherogenicity, will be described in the next subsection. The summary of multiple LDL modifications implicated in atherogenesis is presented in The accumulated evidence indicates that LDL desialylation is tightly implicated in the cholesterol retention process in the arterial wall. On comparison of the atherogenic and non-atherogenic features of LDL, the substantial difference in the sialic acid content of lipoprotein particles was observed . There wTwo approaches were proposed to clarify the mechanisms of intracellular lipid accumulation triggered by desialylated LDL: The first, evaluation of binding, uptake, and degradation of LDL and the second, determination of hydrolysis and esterification rates of lipids in LDL particles. Desialylation was demonstrated to increase the sdLDL particle affinity to the proteoglycans in the arterial wall, therefore, enhancing its binding to the arterial proteoglycans and intracellular uptake, consequently increasing lipid accumulation in the arterial cells ,67. MoreFurthermore, it was shown that not only modified LDL was atherogenic but autoantibodies to modified LDL could also be responsible for blood atherogenicity . The desThe formation of LDL cholesterol-containing circulating immune complexes (CICs) is also a sufficient condition for intracellular cholesterol retention. It was suggested that the exogenous anti-LDL antibodies are pro-atherogenic since their incubation with the normal human serum resulted in the formation of CICs and the stimulation of serum atherogenic properties . Some stThe enzyme trans-sialidase (neuraminidase), which belongs to the family of glycoside hydrolases (EC 3.2.1), was discovered to be accountable for the desialylation of the glycoconjugate of the lipoprotein particles, i.e., transferring sialic acid to different acceptors in the blood plasma . This enFurthermore, trans-sialidase can change the lipoprotein interaction with the arterial cells. It was shown that LDL desialylated by trans-sialidase causes intracellular accumulation of lipids, in association with stimulation of the proliferative activity of vascular cells and synthesis of extracellular matrix components . MoreoveIt is clear that lipidosis plays a crucial role in atherogenesis at the cellular and tissue levels. Therefore, it can represent a key target for the development of early intervention methods for diagnosis and anti-atherosclerotic therapy reducing the burden of CVD management and mortality. The discovery of the atherogenic modifications of lipoprotein particles in the blood of atherosclerotic patients has supported their good predictive and diagnostic value on the molecular level. It allowed identification of some specific prognostic and diagnostic methods for cardiovascular risk and subclinical and clinically manifested atherosclerosis .−/− mice that administration of a sialidase inhibitor 2-deoxy-2,3-dihydro-N-acetylneuraminic acid (DANA) had an anti-atherogenic effect [To date, none of the direct anti-atherosclerotic therapeutic methods is known. Therefore, a novel therapeutic approach, such as the use of trans-sialidase inhibitors was suggested . Using tc effect . The actc effect . Furtherc effect ,92,93. Tc effect . The avac effect . Using Lc effect . These dIt was discovered that a subfraction of the circulating LDL of atherosclerotic patients sustains numerous alterations of protein, carbohydrate, and lipid moieties in the blood plasma, therefore, it was considered as mmLDL, and multiple modifications of LDL determine its atherogenicity. The modified LDL subfraction is capable of inducing the accumulation of lipids in the subendothelial cells, primarily cholesteryl esters that in turn is associated with other cellular atherosclerotic manifestations. Of note, the studies showed that LDL desialylation is the earliest modification, therefore, it plays the most prominent role in the process of cholesterol retention in the subendothelial cells. Relying on the molecular properties of mmLDL, novel specific diagnostic approaches were developed. There is a growing interest in non-pharmaceutical products of natural origin that can be explained by the toxicity and lower efficacy of synthetic substances. Therefore, the alternative therapeutic approaches, such as cell-based models were explored that may help to develop safer long-term treatment schemes using plant-derived compounds. To date, three herbal preparations, namely, Allicor, Inflaminat, and Karinat were developed, as effective anti-atherogenic remedies. Nonetheless, further studies based on the molecular mechanisms of lipid modifications, as well as high-quality large-scale human clinical trials are required, in order to build up a sufficient amount of evidence that would help to establish reliable prognostic/diagnostic biomarkers and therapeutic methods for subclinical and early atherosclerosis that can be applied in clinical practice.


Neuroscientific studies have mostly employed the 20-item Toronto Alexithymia Scale TAS-20;  for the  ShortlyDespite the popularity of the TAS-20 as it provides a brief and easy-to-use tool for alexithymia assessment , caution is advisable.It should be noted that DIF and DDF usually correlate highly, whereas correlations of EOT with DIF and DDF tend to be lower. Although DDF is specifically designed to capture the verbalization of feelings , which is not explicitly part of DIF, one may argue that in order to identify a feeling, attaching a label to that feeling (in terms of inner language) is necessary. From this perspective, DIF and DDF seem relatively closely related as both explicitly refer to emotions, whereas EOT specifically assesses a style of thinking, i.e., a cognitive mode not necessarily including the experience of an emotion.Although more objective measures of alexithymia exist, such as the observer-rated Beth Israel Hospital Questionnaire BIQ; , its modMoreover, a large part of these studies used a certain TAS-20 cut-off sum score to divide participants into two groups, an alexithymic versus a non-alexithymic group or a group of high-scorers versus a group of low-scorers on alexithymia, respectively. Some studies used a cut-off score of 61, which has been suggested to indicate clinically relevant alexithymia . HoweverA related problem is that the “golden standard” of alexithymia assessment, the TAS-20, measures only the three abovementioned facets of alexithymia . These can be considered to capture difficulties in cognitive emotion processing in relation to alexithymia. However, Nemiah and Sifneos’ original conceptualization of the alexithymia construct included not only a cognitive but also an affective component. Nonetheless, the majority of alexithymia studies relied on the TAS-20, neglecting differences in the subjective experience of emotions. This might have further contributed to the equivocality in the literature on alexithymia.Aiming to capture both components and thereby the complete alexithymia construct, the BVAQ was developed . This seToday, the idea of differentiating between different alexithymia dimensions is still considered controversial, and some empirical studies have failed to support this idea . HoweverThe amygdala, a key node of the emotional perception/attention system, is consistently smaller in volume and less activated during negative emotional processing in relation to higher levels of alexithymia. In two fMRI studies using masked priming paradigms, pictures of emotional (happy or sad) faces were masked with neutral faces for a very brief period of time , preventing conscious recognition of the facial emotions . Kugel aThese findings suggest that particularly the DIF facet  of alexithymia is linked to hypoactivation in areas that are important for facial emotion processing during automatic (implicit) emotion processing. fMRI studies investigating the conscious (explicit) processing of emotions observed similar patterns of hypoactivation of the amygdala particularly for DIF in response to fear-inducing and disgusting pictures  and hypoA PET study on hypersensitivity to bodily signals in alexithymia observed hyperactivity of the right insula and the orbitofrontal cortex (part of the PFC) during colonic distension with increasing alexithymia levels . Also heAn fMRI study in patients with depersonalization disorder provided further evidence for distinct neural substrates of the alexithymia facets . TAS-20 Moreover, a recent study investigating social rejection in relation to alexithymia by means of the Cyberball game observed that reduced activation in the dACC during rejection was specifically linked to the DIF facet . Thus, tIn line with the findings reported above, the results of a recent fMRI study in our lab provided evidence for distinct effects of the alexithymia facets on the processing of rewards . While pn > 1,600) VBM study corroborated the notion of neural separability of the alexithymia facets  closely related, and (2) refer to the subjective experience of emotions, i.e., the affective level of emotion processing. This difference might explain why MRI studies focusing on emotion-related areas in the brain usually found correlations with DIF , but rarely with EOT.The evidence regarding the structural correlates of the cognitive and affective alexithymia dimensions is currently less clear. While VBM studies have provided evidence for different structural correlates of the alexithymia dimensions, their results are heterogenous. This may be due to differences in alexithymia assessment and sample sizes between studies. It should also be noted that imaging research on alexithymia has heavily relied on self-report scales, which inherently lack objectivity. Further, it could be a consequence of the persisting uncertainty regarding the validity of the two alexithymia dimensions as based on the BVAQ, especially regarding the inclusion of an emotionalizing factor in the affective dimension .It is thus recommendable that future studies into the multifaceted nature of alexithymia use a multimethod assessment approach as well as large sample sizes to ensure sufficient statistical power. Moreover, it will be important to control for constructs that are closely related to alexithymia, such as negative affectivity, depression, and anxiety, to reach a better understanding of the neural mechanisms that underlie alexithymia and its different facets and dimensions. Such research could have far-reaching clinical implications. In addition to reflecting a fundamental deficit in recognizing and regulating one’s own emotions, alexithymia might be associated with a lack of interoceptive awareness, interrupting the process of simulating the emotions of others in order to empathize with them. Empathy deficits are characteristic of a multitude of psychiatric conditions, including borderline personality disorder, psychopathy, narcissistic personality disorder, and ASD. Given the transdiagnostic significance of these problems and their apparent links to specific facets and dimensions of alexithymia, being able to identify their neural markers could substantially improve the neuropsychiatric assessment of people who are at risk of such disorders, and contribute to the development of individually tailored and thus more effective treatment strategies.The author confirms being the sole contributor of this work and approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Exercise performance is influenced by many physical factors, such as muscle strength and endurance. Particularly in the physical fitness and sports performance contexts, there are many types of ergogenic aids to improve muscular strength and endurance performance, with non-athletes and even athletes using illegal drugs to reach the top. Thus, the development of innovative methods to aid in exercise performance is of great interest. One such method is transcranial direct current stimulation (tDCS). A systematic search was performed on the following databases, until January 2019; PubMed/MEDLINE, SCOPUS, and Pedro database. Studies on tDCS for muscular strength and endurance performance improvement in non-athletes and athletes adults were included. We compared the effect of anodal-tDCS (a-tDCS) to a sham/control condition on the outcomes muscular strength and endurance performance. We found 26 controlled trials. No trial mentions negative side effects of the intervention. The data show differences between the studies investigating muscle strength and the studies evaluating endurance, with regard to successful use of tDCS. Studies investigating the efficiency of tDCS on improving muscular strength demonstrate positive effects of a-tDCS in 66.7% of parameters tested. In contrast, in studies evaluating the effects of a-tDCS on improving endurance performance the a-tDCS revealed a significant improvement in only 50% of parameters assessed. The majority of the data shows consistently influence of a-tDCS on muscular strength, but not to endurance performance. The results of this systematic review suggest that a-tDCS can improve muscular strength, but not to endurance performance. Exercise performance is influenced by many physical factors, such as muscle strength and endurance , or cortical inhibition, by hyperpolarization of the membrane resting potential    inclusion criteria. Participants were healthy men and women adults, athletes, strength and endurance training practitioners or sedentary, with no history of mioarticular injury and no psychiatric illness. Intervention were used the effects of the anode stimulus of tDCS (a-tDCS). Comparators were sham tDCS  or no interventions . Outcomes for both the muscular strength and endurance were evaluated from different points of view: (1) physical tasks that consist of uniarticular exercise or multiarticular exercise; (2) physical performance that was measured objectively as endurance time, total work performed, force production during a maximal voluntary contraction (MVC), peak power, mean power, and/or time to exhaustion. All these variables are considered the primary outcomes of our review. Study Design were only randomized and non-randomized trials, using either cross-over or parallel group designs, comparing an intervention encompassing a-tDCS with a sham group on muscle strength or no intervention.We analyzed only studies published in English language. A systematic literature search was conducted between December 10−2018 and January 10−2019. The following databases were used: PubMed, ISI Web of Science, and Scopus. No filters were applied in the search.The search was performed using the terms physical exercise, strength training, resistance training, endurance training, cycling, effort, physical exertion, fatigue, and athletic performance, individually combined with transcranial direct current stimulation and tDCS, in all databases.Included important reports and reviews regarding tDCS and muscle strength or endurance were manually screened for additional relevant studies. Experts on the field, including authors from the reports, were also requested to suggest any additional trials in order to ensure that the review was as comprehensive and up-to-date as possible.To facilitate the interpretation of our results, the findings were structured in two categories: (i) studies on the effects of tDCS on muscle strength performance (ii) studies on the effects of tDCS on endurance performance. This strategy was used due to the need to differ these physical tasks in terms of physiological responses , a total of 1,042 articles remained. One thousand sixteen articles were removed by title and/or abstract. After the removal process, 26 articles were included for systematic review, 18 examining the effects of tDCS on muscular strength performance and 8 on endurance performance. Flow chart is presented in The results identified a total of 1,067 articles . After the removal process of duplicate articles   , two studies showed difference between a-tDCS and sham conditions  , the dorsolateral prefrontal cortex (CPFDL), and the insular cortex (IC).Regarding brain areas, M1 is the most related to exercise performance due to its role in motor execution. Studies have consistently shown that central fatigue can compromise the physical performance of exercises of small muscle groups , as well as exercises of large muscle groups . Specifically, spinal and supraspinal factors, such as reduced excitability of the motorneuron pool and the inability or limited ability of M1 and other supraspinal areas to increase the neural drive to compensate for this decrease in spinal excitability leads to decreased muscle capacity to produce strength/power and thus cause fatigue , considered as a responsible for cardiac autonomic control. Several types of studies indicate that the right IC is responsible for sympathetic modulation while the left IC is responsible for the parasympathetic modulation  primary motor cortex (M1) has been the most targeted area; (ii) a-tDCS was delivered main before the physical task; (iii) most of the studies applied 20 min of stimulation at 2 mA with an active electrode size of 35 cmWith respect to resistance, Cogiamanian et al.  suggesteStudies that investigated the effects of tDCS on muscle strength indicate that performance improvement was achieved both by increased corticospinal excitability and by reduced short-interval intracortical inhibition and increased cross-activation  (Wagner et al., The results of this systematic review suggest that a-tDCS can improve muscular strength, but not to endurance performance. Nevertheless, evidence is insufficient to guarantee its effectiveness. New studies are required to assess the long-term effects of tDCS application combined with exercise training, whether with athletes or non-athletes. Despite tDCS is still considered a new tool in exercise and sport performance, it seems to have potential to improve performance. In line with this, more rigorous and extensive experimental studies are needed in order to better understand possible side effects from either regular use or abuse. Other important point that is needed is doing more studies with larger samples, appropriate blinding methods and techniques to examine neurophysiological mechanisms of tDCS.SM and PJ designed the study, acquired and analyzed the data, and wrote the first draft of the paper. VA and JV helped to design the study, to organize the data acquired, and to discuss the first draft of the paper.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Up until the middle of the twentieth century, neuroscience dogma emphasized the fixed, immutable nature of the brain. In the 1960s, however, in what was arguably one of the most revolutionary research programs in neuroscience, a team of researchers at UC Berkeley generated data revealing the dynamic characteristics of mature neural systems. Working with Edward Bennett, David Krech, and Mark Rosenzweig, Marian Diamond (1926-2017) documented the neuroanatomical changes in rats exposed to enriched environments—findings that threatened prior notions of brains being “fixed in stone” . Not to be dissuaded, Diamond continued her neuroanatomical explorations, verifying that rats exposed to novel and complex environments experienced equally complex neural changes, especially in the cerebral cortex. Although hints of neural plasticity had been introduced by individuals such as Charles Darwin and Donald Hebb prior to Diamond's research, she has been credited for providing tangible evidence of neuroplasticity. One of her colleagues at the University of California at Berkeley, George Brooks, wrote in her obituary, “Dr. Diamond showed anatomically, for the first time, what we now call plasticity of the brain” Sanders, . She wasDedicated to Dr. Diamond, the current Research Topic focuses on environmental enrichment in terms of neuroprotection/rehabilitation and the use of this system in the laboratory to promote species-typical behavior and generalizable, rigorous investigation into the effects of experience on behavior and physiology.Bailoo et al. demonstrate that this may be an unfounded assumption. The coefficient of variation across housing conditions did not differ on measures of behavior, growth, or stress physiology. Additionally, the more enrichment provided, the more engagement mice had with their environment. Similarly, Neal et al. report that enhanced social environments facilitate affiliative behaviors and appear to promote problem solving behaviors. Together, this underscores the importance of enrichment for healthy species-typical behaviors.Concerns that environmental enrichment may increase variability in experimental endpoints, affecting reproducibility, have impeded the expansion of its use in research. Data described by Morano et al. demonstrated that removing female rats from environmental enrichment mimics an experience of “loss,” leading to increased passive coping behavior, hyperphagia, and evidence of HPA axis dysregulation. These behavioral and physiological changes are associated with an array of psychiatric disease states, suggestive of the utility of this model for understanding loss-related dysfunctions. In contrast, Cutuli et al. review the effects of enrichment exposure across critical periods of development, particularly on parental care and offspring outcomes. Moreover, they provide a specific emphasis on the importance of pre-reproductive vs. post-reproductive experiences and transgenerational effects, highlighting some of their own research findings.McQuaid et al. show that post-weaning enrichment increases demonstrations of social behavior, buffered corticosterone, and central cytokine levels, and elevated brain-derived neurotrophic factor in the prefrontal cortex of male mice, following stressor exposure in adulthood.While environmental enrichment can be stressful to some male animals, Environmental enrichment has been demonstrated to induce therapeutic effects in a wide range of preclinical models of neurological and psychiatric disorders. Various articles in this Research Topic have addressed this important issue, providing new insights into molecular and cellular mechanisms of experience-dependent plasticity, and identifying novel candidate targets for enviromimetics , is transcriptional modulation of components of the serotonergic system. Furthermore, these investigators compared EE with an exercise (voluntary wheel running) intervention and found key differences between these two environmental interventions, as well as interesting region-specific and sexually dimorphic effects on gene expression. Finally, they were able to demonstrate functional consequences of the EE effect, via behavioral pharmacology.The first demonstration that EE can be beneficial in a genetic model of a human disorder utilized a transgenic mouse model of Huntington's disease  to create a “two hit model” of relevance to specific neurodevelopmental and psychiatric disorders. Interestingly, these authors also found sexually dimorphic effects of EE, and were able to correlate their behavioral data with expression levels of the neurotrophin receptor TrkB  and specific NMDA receptor subunits, reinforcing the evidence for a role of neurotrophic and glutamatergic signaling in mediating the therapeutic effects of EE.The effects of EE on a different mouse model, with haploinsufficiency in the brain-derived neurotrophic factor (BDNF) gene, were described by Mason et al. have addressed this via a form of nesting enrichment called “closed nest boxes.” This form of nesting enrichment was shown to induce beneficial effects in a model of neonatal hypoxia-ischemia. Interestingly, molecular correlates included BDNF and glial-derived neurotrophic factor (GDNF), and sexually dimorphic effects were observed, which has become a recurring theme in EE studies.Another key aspect of EE, which has been often overlooked, is enrichment of the nest conditions in rodent models. Bhaskar et al. have combined EE with deep-brain stimulation (DBS) and found that the combination increased anxiolytic effects relative to the same DBS intervention performed in standard-housed animals. Combining EE with other interventions, both pharmacological  to determine its expression across normal aging and its interaction with the environment. Enrichment housing transiently increased CNP availability in young, but not older rats. This may be suggestive of age-related losses in sensitivity to environmental stimulation.McDonald et al. describe many obstacles to application of environmental enrichment paradigms to patients experiencing stroke. The work highlights the variation between animal and clinical models of enrichment, suggesting that greater alignment is required to improve translation.The benefits of environmental enrichment are reported in preclinical settings with little focus on translation. The potential for the environment to influence behavior has a long history, and subsequent work implicating correlative brain changes were pioneered by Dr. Marian Diamond. The contributions to this Research Topic offer findings regarding enrichment promoting healthy species-typical behavior in the lab and reversing insult. It is the hope of the editors that this evidence will support wider adoption of enrichment in normal housing protocols.McDonald et al. intimate, this may very well present an opportunity to translate successful interventions to clinical populations. Additional work that advances understanding of the mechanisms underlying the benefits of enrichment in healthy and injured/adverse populations is also warranted . Few researchers are attending to the intergenerational benefits of enrichment  and variation across the age axis, so continued efforts in these areas are also necessary.We also hope that further work is accomplished that delineates After more than six decades of work on environmental enrichment, we applaud the advances in understanding relevant biological parameters and key mechanisms, and emphasize its potential for adaptation to clinical populations, across a broad spectrum of neurological and psychiatric disorders.All authors contributed to the writing of the editorial. AK and SD facilitated the concept, design, and overall development of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Hypotheses and theoretical frameworks are needed to organize and interpret the wealth of data on the organization of cortical networks in humans and animals in the light of development, evolution, and selective vulnerability to pathology. Goulas and colleagues compared several hypotheses of cortical network organization in 4 mammalian species and conclude that (1) the laminar pattern of cortico-cortical connections is better predicted by the Structural Model, which relates cytoarchitectonic differences of cortical areas to their interconnectedness, and (2) the existence of cortico-cortical connections is related to cytoarchitectonic differences and the physical distance between cortical areas. The predictions of the Structural Model can be applied to the human cortex, in which invasive studies are precluded. Goulas and colleagues advance interesting questions regarding the emergence of cortical structure and networks in development and evolution. Validated theories of cortical structure, development, and function can guide studies of cortical networks likely affected in neurodevelopmental disorders. This Primer explores recent research into the common organizational principles and specializations of the cerebral cortex; these reflect convergence and divergence of evolutionary and developmental mechanisms, and form a basis for understanding cortical function and pathology. Mapping cortical structure and connections is needed to understand brain function and pathology. Noninvasive tractography and imaging play a major role in advancing our understanding of the typical and atypical development, organization, and function of major cortical networks in humans. However, to identify key features of cortical pathways like laminar patterns and cellular interactions at the synapse level, we rely on invasive neuroanatomical tract-tracing studies in animals. This raises the question of whether or not we can use the wealth of detailed information on the structure and connections of the cerebral cortex in mammals to understand cortical pathways in humans and their disruption in disease. To answer this question, we must identify fundamental principles of cortical structure and network organization that are common across mammals. It is also important to pinpoint species-specific specializations that differentiate humans from other mammals. Collectively, common organizational principles and specializations of the cerebral cortex reflect convergence and divergence of evolutionary and developmental mechanisms and form the basis to understand cortical function and pathology.The cerebral cortex is at the highest level in the hierarchies of neural pathways. Pathways of all internal or external sensory modalities originate in peripheral receptors and ascend in the central nervous system through successive levels to reach the cerebral cortex. In the reverse direction, commands for effectors descend from the cortex to the motor nuclei in the brainstem and the spinal cord (motor actions) and the hypothalamus (autonomic responses and neuroendocrine regulation) .Neural processing within the cerebral cortex is also hierarchically organized. Sensory pathways of each modality access the cerebral cortex through primary areas, which are the first and lowest level in cortical hierarchies. Up one level, there are unimodal association areas that elaborate information from diverse feature-sets within one sensory modality. Pathways from unimodal association areas converge in multimodal association areas and, finally, in limbic areas, the less specialized cortical areas at the last and highest level in cortical hierarchies –4. The fA major structural feature of the cerebral cortex is the arrangement of cortical neurons in layers. Pathways connecting cortical areas originate and end in different layers showing different laminar patterns of connections. Feedforward pathways originate in neurons in the supragranular layers II–III and target middle and infragranular layers. Feedback pathways originate in infragranular layers V–VI and target mostly superficial layers I–III. Lateral connections between cortical areas at the same level of the cortical hierarchy originate in supragranular layers II–III and infragranular layers V–VI and terminate in all layers .The intricate network of cortical connections forms the neural basis for most aspects of flexible behavior like cognition, emotion, attention, memory, decision making, action, and consciousness e. g., ,6,9). Is,9. Is6,9PLoS Biology, Goulas and colleagues )lleagues  search flleagues . Anotherlleagues . A thirdlleagues ,16.After comparing these theoretical frameworks Goulas and colleagues  show thaGoulas and colleagues  add to oAs outlined above, the Structural Model relates laminar patterns of connections to the laminar elaboration of the connected areas. Cortical areas, each with characteristic architecture, can be sorted into a few cortical types according to the elaboration of their laminar structure. Laminar architecture varies gradually and systematically across the cerebral cortex dividing the cortical landscape into a minimum of 3 major cortical types that are present in different proportions across mammalian species: agranular if they lack the granular cell layer IV, dysgranular if they have an incipient granular layer IV, and eulaminate areas if they have 6 well-developed layers ,20.Several architectonic features are correlated, in part, with cortical type. For instance, neuron density, the content of intracortical myelin, or the expression of the nonphosphorylated intermediate neurofilament protein Sternberger-Meyer monoclonal antibody to a nonphosphorylated epitope on human NF-M and NF-H subunits of neurofilament protein (SMI-32) increase, in general, but not always, with laminar elaboration ,9,16,21.An intriguing question discussed by Goulas and colleagues  is the dIn this context, the shape of major white matter pathways in the human brain may give us additional clues about the development of cortical networks. It is interesting to note that the cingulate bundle and the uncinate fasciculus that connect limbic areas across lobes are curved. In contrast, the superior and inferior longitudinal fasciculi connect eulaminate areas and are straight . Based oSystematic variation of laminar structure is also rooted in evolution. Two developmental organizers, the hem and the antihem, have likely directed the expansion of the neocortex from rodents to primates (A key aspect of the Structural Model highlighted by Goulas and colleagues  and otheIn line with the predictions of the Structural Model, a recent functional study in human subjects confirmed that cortical areas of comparable architecture are more likely to be connected . With reThe emergence of the blueprint of the cortical connectome highlighted by Goulas and colleagues  likely dIn summary, the relationship of cortical structure with the strength and laminar pattern of connections in mammalian species provides a framework to better understand the development and evolution of cortical networks in humans. This framework, validated by Goulas and colleagues , can be