The hypocretin (Hcrt) system has been implicated in a wide range of physiological functions from sleep-wake regulation to cardiovascular, behavioral, metabolic, and thermoregulagtory control. These wide-ranging physiological effects have challenged the identification of a parsimonious function for Hcrt. A compelling hypothesis suggests that Hcrt plays a role in the integration of sleep-wake neurophysiology with energy metabolism. For example, Hcrt neurons promote waking and feeding, but are also sensors of energy balance. Loss of Hcrt function leads to an increase in REM sleep propensity, but a potential role for Hcrt linking energy balance with REM sleep expression has not been addressed. Here we examine a potential role for Hcrt and the lateral hypothalamus (LH) in state-dependent resource allocation as a means of optimizing resource utilization and, as a result, energy conservation. We review the energy allocation hypothesis of sleep and how state-dependent metabolic partitioning may contribute toward energy conservation, but with additional examination of how the loss of thermoregulatory function during REM sleep may impact resource optimization. Optimization of energy expenditures at the whole organism level necessitates a top-down network responsible for coordinating metabolic operations in a state-dependent manner across organ systems. In this context, we then specifically examine the potential role of the LH in regulating this output control, including the contribution from both Hcrt and melanin concentrating hormone (MCH) neurons among a diverse LH cell population. We propose that this hypothalamic integration system is responsible for global shifts in state-dependent resource allocations, ultimately promoting resource optimization and an energy conservation function of sleep-wake cycling. In the 20 years since the discovery of the hypocretin/orexin (Hcrt) system, a growing diversity of physiological and neurobehavioral responses under Hcrt control has challenged identification of a unifying function. A compelling hypothesis suggests that Hcrt plays a role in the integration of sleep-wake neurophysiology with energy metabolism –3. Hcrt Hypocretins 1 and 2 (Hcrt1 and Hcrt2), also called orexins A and B, are excitatory hypothalamic neuropeptides that are derived from a single precursor molecule by proteolytic processing and are largely co-localized in the same neurons . They weHcrt neurons are found exclusively in the posterior lateral hypothalamus (LH) –13, numbHere, on the 20th anniversary of its discovery, we examine a potential role for Hcrt in optimizing efficiencies in energy utilization and, thus, energy conservation. Our recent energy allocation hypothesis of sleep proposes that state-dependent metabolic partitioning at the whole organism level provides greater daily energy conservation through resource optimization than the measured metabolic rate reduction observed during sleep , 38. A bSleep has long been considered an energy conservation strategy, potentially explaining its universal presence across the animal kingdom –41. HoweMoreover, metabolic rate reduction during sleep, analogous to torpor as the principal mechanism of energy conservation, assumes that all biological processes are equally reduced during sleep compared to wake. However, sleep is a highly active metabolic state during which many specific biological operations are upregulated, contradicting the notion that sleep, like hibernation, involves the global downregulation of metabolic processes. These functions specifically upregulated during sleep compared to wake include protein biosynthesis, intracellular transport and membrane repair , 48, immOur recent energy allocation hypothesis views sleep-wake cycling as a behavioral strategy promoting energy conservation through dynamic state-dependent metabolic partitioning and resource optimization , 38. A bThe energy allocation hypothesis of sleep proposes that state-dependent metabolic partitioning provides greater daily energy conservation than the measured metabolic rate reduction observed during sleep , 38. BasSeveral important principles emerge from this mathematical modeling, including why sleep may be a better behavioral strategy than quiet wakefulness with respect to resource optimization and energy savings. This modeling suggests that metabolic partitioning by state is constrained if energy deployment toward waking-related processes is maintained during the rest phase, whereas energy savings are amplified if waking-related allocations during the rest phase are eliminated . This meWe will now review the role of Hcrt on modulating a wide range of physiological responses. Understanding these diverse physiological effects will allow us to explore a potential role for Hcrt in a broader perspective as a network control system promoting resource optimization.The Hcrt system was first linked to sleep function through the discovery that a significant loss of Hcrt neurons leads to narcolepsy, a condition characterized by excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic hallucinations , 59. TheOptogenetic activation of Hcrt neurons increases the probability of sleep to wake transitions from either NREM or REM sleep  throughoThe narcoleptic phenotype not only leads to excessive daytime sleepiness, but also to fragmented sleep with many brief arousals –65. SuchThermoregulation is tightly integrated with the sleep-wake cycle in mammals and is an important function of Hcrt. In healthy subjects during sleep, decreased heat production from reduced muscle activity and lower basal metabolism contribute to a body temperature that is regulated at a lower level , 71. AddCompared to healthy controls, narcoleptics show lower core body temperatures while awake  and highAn altered pattern of skin-temperature regulation is also reported in patients suffering from narcolepsy . In healNarcoleptic subjects during the waking period show higher distal skin temperatures with lower proximal skin temperatures, which may either reflect or contribute to the sleepiness of narcolepsy  as this The Hcrt system also plays an important role in increasing core body temperature by activating brown adipose tissue (BAT) , 89, sugHypocretin is also called orexin because of its role in feeding, as orexin means “appetite” in Greek. In mammals, arousal is reduced after feeding and increased during fasting , 97–99, Food seeking behavior caries an essential survival function and is a potent reward stimulus. Multiple studies show that Hcrt plays an active role in reward processing for both food and drug-seeking behaviors. Human narcoleptics rarely show stimulant abuse or drug seeking behavior even though they are treated for years with stimulants . The firFinally, Hcrt also mediates autonomic and cardiovascular effects associated with sleep and waking. For example, there are several well-known sleep-associated cardiovascular changes. One such change is the decrease in blood pressure that occurs during sleep in a variety of species, a phenomenon generally referred to as “dipping” –115. DipIn summary, these data demonstrate that Hcrt plays a role in feeding and sleep-wake modulation, as well as numerous other physiological processes such as thermoregulation, motivation and reward, autonomic and neuroendocrine modulation. We will next review how the Hcrt system, together with other LH cell populations, may integrate these physiological responses with respect to the energy status of the organism. Finally, we will propose a unifying role for Hcrt that includes NREM and REM sleep regulation, particularly NREM-REM cycling, with respect to resource optimization and energy conservation.In this section, we will describe how, during fasting when energy resources are low, Hcrt promotes wakefulness and food seeking behavior. In contrast, in the presence of a positive energy balance after feeding, other cell types within the LH, such as melanin concentrating hormone (MCH) neurons, promote sleep. We will also examine how the LH, through reciprocal interactions between heterogeneous neuronal populations, may coordinate global shifts in resource utilization through sleep-wake state transitions. Importantly, these reciprocal interactions within hypothalamic circuits suggest that Hcrt not only mobilizes or promotes a waking response, but actively inhibits sleep-related processes and thus contributes to a state-dependent partitioning of biological operations, a mechanism that we propose is central to an energy conservation function of sleep-wake cycling.As was originally hypothesized in the 1930's, behavioral state control is, in part, anatomically segregated within the hypothalamus , 122. HiAnteriorly, several structures are particularly noteworthy. The ventrolateral preoptic nucleus (VLPO) within the preoptic area plays an important role in initiating sleep and driving NREM sleep , 127. AnInitially considered as only a waking center, the posterior LH has been shown to regulate behavioral state transitions from NREM sleep to either REM sleep or wakefulness , 139. AlIn contrast to Hcrt and its predominant role in wakefulness, it is now well-established that the MCH neuronal system modulates REM sleep expression –147, at The Hcrt and MCH neuronal systems are intermingled within the LH and generally fire reciprocally , 157. FoHcrt and MCH neurons also generally respond with opposite activity patterns to the nutritional state of the organism, and thus energy balance, through their receptivity to numerous biomarkers related to energy status. To illustrate, Hcrt neurons are inhibited by biomarkers which are released in response to food intake, such as leptin (satiety hormone produced by adipose tissues), glucose, and neuropeptide Y , 163–165MCH neurons are responsive to insulin and glucose, but they demonstrate an opposite response pattern compared to Hcrt neurons , 174. FoTaken together, these data demonstrate multiple complimentary and redundant mechanisms by which the LH may tightly monitor energy status of the organism. Moreover, these data are consistent with the hypothesis that the posterior LH integrates energy status and sleep-wake modulation, at least in part through the reciprocal activation of the MCH and Hcrt systems.Although MCH promotes sleep and is responsive to energy status, a considerable body of literature indicates that MCH, like Hcrt, also regulates feeding behavior. Interestingly, the MCH system may promote feeding behavior while also decreasing both locomotor activity and BAT thermogenesis, thereby contributing to a positive energy balance and potentially conserving energy for homeostatic purposes –187. DinConsistent with their roles in behavioral state modulation and global shifts in peripheral responses, both Hcrt and MCH neuronal populations show wide-spread projections throughout the brain to similar brain areas as shown in Figure After entering NREM sleep, an organism must make a decision as to when it should transition back to wake or, instead, enter REM sleep. One of the most consistent findings in mammalian sleep is the highly structured cycling between NREM and REM sleep. Although the purpose of this cycling is not understood, the duration from one REM period to the next is markedly consistent within any given species of mammal even when considering inter-individual variation. Indeed, one of the strongest phylogenetic correlations across species with respect to sleep parameters thus far examined is between REM-REM cycle length and body mass –196. ThaWe recently proposed that REM sleep cycles with NREM sleep based on thermoregulatory constraints as a means of optimizing REM sleep expression and resource allocations . During The energy allocation hypothesis postulates that REM sleep is a behavioral strategy that reallocates resources away from costly thermoregulatory defenses into REM sleep-specific biological functions to improve reproductive success or evolutionary fitness . Indeed,It is well-established that ambient temperature warming toward the high end of the TNZ increases REM sleep expression across mammalian species, whereas any deviation away from thermoneutrality preferentially decreases REM sleep over NREM sleep , 210–215The LH may play an important role in integrating inputs related to ambient temperature, energy balance and sleep pressure for the output control of transitions from NREM sleep to either wakefulness or REM sleep  energy expenditure is decreased in Hcrt-KO mice compared to WT controls , the losBL has written the majority of the text. AA and CB supported this article by revising it critically. MHS is responsible for the concepts and design of the review, as well as writing significant passages and text editing.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.


Bipolar disorder (BPD) is a mood disorder, which is characterized by alternating affective states, namely (hypo)mania, depression, and euthymia. Evidence is growing that BPD has indeed a biologic substrate characterized by chronic inflammation, oxidative stress, and disturbed energy metabolism. Apart from this, there is obviously a hereditary component of this disease with multi-genetic factors. Most probably a susceptibility threshold favors the outbreak of clinical disease after a cascade of stress events that remain to be elucidated in more detail. Evidence is also growing that weak points in brain energy metabolism contribute to outbreak and severity of BPD. Conventional psychopharmacologic therapy must be reassessed under the aspects of weight cycling and development of central obesity as a deterioration factor for a worse clinical course leading to early cardiovascular events in BPD subgroups. Bipolar disorder (BD) is a mood disease, which is characterized by alternating affective states between the poles of euphoria or dysphoria, euthymia, and depression , 2. SympThe course of illness is classified according to the current revision of the DSM 5—as BD I, BD II and cyclothymic disorder. Individuals with BD I suffer from recurrent episodes of manic, depressed, or mixed episodes. In contrast, individuals with BD II disorder present only hypomanic and depressed episodes. Individuals with cyclothymic disorder show over at least 2 years symptoms of dysthymic mood and mild hypomanic episodes, which do not fulfill the criteria for bipolar II disorder or major depressive disorder (MDD) .According to current scientific knowledge, the occurrence of BD is best explained by the vulnerability-stress-model, which links a strong genetic heritability, chronic stress, and acute triggers . An orchIndividuals with BD frequently suffer from uncontrolled weight gain and cardiovascular disease (CVD) , 13. AccMoreover, BD was particularly associated with mitochondrial dysfunction in serum metabolomics analyses. The citric acid cycle, urea cycle, and amino acid metabolism were each affected in BD and may, to some degree, explain dysregulation in obesity related pathways . NeverthIt is well-known that some kinds of psychopharmacological medication, basically sedating antidepressants  and sedating atypical antipsychotics , as well as mood stabilizing agents  can lead to increased appetite and associated weight gain . Yet, noPTPRD gene , and GFPT2 gene   is associated with AIWG and comprehensive reviews are summarizing this topic , which analyzed antipsychotic-induced weight gain (AIWG) found a genome wide association of AIWG with gene variants in the 2386481) . Neverthis topic .Valproate and lithium also feature weight gain as a side effect and both interact with HDACs (histone deacetylases), which are important enzymes for epigenetic modulation by catalyzing the deacetylation of histones. The deacetylation of histones induces a tighter wrapping of proteins around the DNA and blocks transcription by physically limiting the access of transcription factors , 20. ValLiterature shows for example that patients suffering from mild Rett syndrome, which includes mutations in MeCP2, commonly show obesity . FurtherEven though psychopharmacological side effects can to some degree explain weight gain and obesity in BD, the association still exists even when controlled for psychopharmacological medication in statistical analyses. There are globally diverse research groups, which analyse obesity as a trait marker for BD itself, as the observed increased rate of obesity cannot be explained by medication alone , 13. To Adipokine alterations were associated with BD in previous literature . PlatzerAdiponectin, a collagen-like adipocytokine is exclusively and abundantly expressed in adipose tissue. It circulates in peripheral blood in low molecular weight (LMW), medium molecular weight (MMW), and high molecular weight (HMW) isoforms also called sub fractions or multimers . It has Since adiponectin exerts anti-inflammatory properties, the reduction of total adiponectin in BD may explain to some degree the proneness toward a mild chronic inflammation seen in BD . This coIn another investigation a positive correlation between high sensitive (hs) C-reactive protein and the number of manic and depressive episodes was shown in females with BD . The milOxidative stress and ER stress have been associated with BD in diverse lines of evidence . Oxidatiin-vitro studies (BiP gene expression was significantly increased and unspliced XBP1 (but not the XBP1 splicing event itself) was significantly decreased in fasting blood of patients with BD compared to healthy controls in the “BIPFAT study”  can induce ROS. The other way oxidative stress can affect the correct folding of proteins, which can induce ER stress is by misfolding or unfolding of proteins , 54. Obe studies –59. The ARNTL in fasting blood DNA of BD study participants . There is also a second critical biochemical pathway which involves tryptophan, namely the formation of KYN . The enzMAOA] and catechol-O-methyltransferase)  . It is w studies , 77. Intnd NPAS2 , 79. Thuproducts , 80, 81.ne ARNTL . Disturbne ARNTL . AgainstThe question to what extent weight gain or loss influences the therapeutic response in BD is still unanswered. Indirect evidence for a positive effect of weight loss on mood comes from obese patients showing an improved long-term depression outcome after bariatric surgery . In a smChronic inflammation, decreased insulin action, and oxidative stress most likely address biologic weak points of BD patients and thus aggravate the clinical course of disease. It is possible that latent defects of the energy metabolism may represent one important weak point. Apart from this, increased social exclusion caused by obesity will open the way to psychiatric decompensation. An improved metabolic/inflammatory state and a stronger self-esteem after weight loss will pave the way for amelioration of disease drivers.On the other hand, medications for BD associate with weight gain, highlighting the need for the development of more weight-neutral, effective treatments. Preventative interventions have shown some promise for preventing medication related weight gain and deserve further research attention. While there is some evidence for the use of behavioral and medical strategies for weight loss in BD, bariatric surgery may potentially be the most robust intervention in adipose patients with stable BD. While existing research supports the use of bariatric surgery in patients with a well-managed bipolar disorder, further longitudinal investigation is needed to address specific predictors of success in this population . On the Evidence is growing that BD has indeed a biologic basis characterized by chronic inflammation, oxidative stress, and disturbed energy metabolism . Apart fAll authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.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.


Open drains are common methods of transporting solid waste and excreta in low-income urban neighborhoods. Open drains can overflow due to blockages with solid waste and during rainfall, posing exposure risks. The goal of this study was to evaluate whether pediatric enteric infection was associated with open drains and flooding in a dense, low-income, urban neighborhood.As part of the MAL-ED study in Vellore, India, a cohort of 230 children provided stool specimens at 14–17 scheduled home visits and during diarrheal episodes in the first two years of life. All specimens were analyzed for enteric pathogens. Caregivers in 100 households reported on flooding of drains and households and monthly frequency of contact with open drains and flood water. Household GPS points were collected. Monthly rainfall totals for the Vellore district were collected from the Indian Meteorological Department. Clustering of reported drain and house flooding were identified by Kulldorff’s Bernoulli Spatial Scan. Differences in enteric infection were assessed for household responses and spatial clusters, with interactions between reported flooding and rainfall to approximate monthly drain flooding retrospectively, using multivariable, mixed-effects logistic regression models.Coverage of household toilets was low (33%), and most toilets (82%) discharged directly into open drains, suggesting poor neighborhood fecal sludge management. Odds of enteric infection increased significantly with total monthly rainfall for children who lived in households that reported that the nearby drain flooded  and for children in households in a downstream spatial cluster of reported drain flooding . There was no association between odds of enteric infection and frequency of reported contact with drain or floodwater.Children in areas susceptible to open drain flooding had increased odds of enteric infection as rainfall increased. Results suggested that infection increased with rainfall due to neighborhood infrastructure  and not frequency of contact. Thus, these exposures may not be mitigated by changes in personal behaviors alone. These results underscore the importance of improving the neighborhood environment to improve children’s health in low-income, urban settings.The online version of this article (10.1186/s12889-019-7268-1) contains supplementary material, which is available to authorized users. Enteric infections may be transmitted through contaminated water, poor sanitation, and inadequate hygiene (WASH). While research on the impact of WASH on reported diarrheal symptoms is common , researcUrban infrastructure can mitigate or facilitate personal exposures to fecal contamination in the household and public environments depending on the effectiveness of the fecal sludge management, drainage, and wastewater systems –14. WhilChildren’s exposure to environmental fecal contamination may vary by magnitude of the contamination in the environment, the frequency and type of contact (direct or indirect), and the ingested dose. For example, direct contact with highly contaminated open drains can result in incidental ingestion of a high dose of fecal contamination from a single event, while consumption of municipal water may yield the same cumulative dose through more frequent exposures to lower concentrations of fecal contamination , 37, 38.Open drains are commonly used to transport runoff and fecal sludge from households and have been recognized, along with their associated flooding, as risk factors for infection in QMRAs –12. Yet,Data on enteric infection (the main outcome of this study) and household socioeconomic status (an a priori covariate for adjusted models in this study) from The Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and Consequences for Child Health and Development Project (MAL-ED study);Exposure data  from the SaniPath Exposure Assessment Tool;Publicly-available district-level data on cumulative monthly rainfall and average monthly temperature  from the Customized Rainfall Information System (CRIS) Hydromet Division of the India Meteorological Department , 43–47 aThis study was a sub-analysis of several studies conducted in the Old Town neighborhood of Vellore, India. It used three sources of data:The MAL-ED study in Vellore was conducted by the Christian Medical College and Hospital, Vellore (CMC). The birth cohort was enrolled from March 2010 – February 2012, and data collection ended in February 2014. Community mapping and household surveys as part of the SaniPath Exposure Assessment Tool deployment were conducted by Emory University, in collaboration with CMC, in February – March 2014. Thus, assessment of exposures  occurred after outcome measurement. Some of the methods of this study (enteric infection measurement and exposure data collection) have been published previously .2), poor sanitation, and high burden of enteric disease , and the absence of sewage treatment facilities [unpublished data], the open drains in this neighborhood acted as de facto sewerage and solid waste disposal systems . These dudy area . These dudy area . The cloudy area –59. Thusudy area , the eleThe absence of such a dose-response relationship suggests that children in households, and their parents, would be unable to mitigate their exposures and subsequent odds of infection by themselves. For example, reducing contact with open drains through individual behaviors would be ineffective if the dose in a single exposure is sufficient to cause infection. Therefore, common infrastructure solutions that reduce, but do not eliminate, contact with drains (such as fences or drain covers) would also be ineffective if drains routinely overflow their bounds , 10. ThuMeasures of household assets, income, and mother’s education from robust, multiple-time-point assessments during the MAL-ED follow-up period minimized confounding due to SES within the study population . AlthougThis study has some other notable strengths and limitations in outcome and exposure measurements. Measurement of enteric infection from stool specimens collected regularly over the first two years of life provided a sensitive and objective health outcome measure for examining associations with environmental exposures compared to use of self-reported diarrhea alone , 61, 62.Mitigation of pediatric enteric infection in urban environments requires understanding neighborhood-level infrastructure and geography, magnitude of environmental contamination, and frequency of behaviors associated with exposure to fecal contamination. Household-level WASH interventions alone may not be sufficient to reduce these risks . HousehoIn this setting, significant associations between pediatric enteric infection and areas subject to flooding of open drains were observed due to inadequate local sanitation infrastructure (including neighborhood-level FSM) and heavy rainfall, independent of the reported frequency of contact with open drains. Because households are less likely to be able to prevent these exposures to fecal contamination from floods through changing individual behaviors alone, changes to local infrastructure must occur to mitigate these exposures within public environments. Efforts to design effective interventions to improve the health of children in low-income, urban neighborhoods need to recognize both the interconnectedness of the public and private domains and the associations between infrastructure, geography, rainfall, and exposure behaviors in the transmission of enteric pathogens.Additional file 1:Organisms tested in stool specimens. (DOCX 13 kb)


The colonization of plant tissues by pathogenic and symbiotic microbes is associated with a strong and directed effort to reprogram host cells in order to permit, promote and sustain microbial growth. In response to colonization, hosts accommodate or sequester invading microbes by activating a set of complex regulatory programs that initiate symbioses or bolster defenses. Extensive research has elucidated a suite of molecular and physiological responses occurring in plant hosts and their microbial partners; however, this information is mostly limited to model systems representing evolutionarily young plant lineages such as angiosperms. The extent to which these processes are conserved across land plants is therefore poorly understood. In this review, we outline key aspects of host reprogramming that occur during plant–microbe interactions in early diverging land plants belonging to the bryophytes . We discuss how further knowledge of bryophyte–microbe interactions will advance our understanding of how plants and microbes co-operated and clashed during the conquest of land. Interactions between plants and microbes can have beneficial, neutral or detrimental effects on host fitness. In general, most plants are resistant to most microbes, as they employ several layers of sophisticated immune mechanisms to ward off intruders . HoweverMuch of what we know about plant–microbe interactions is derived from studies performed in angiosperms, which have revealed conserved and unique mechanisms across a diverse range of flowering plants. From the microbial perspective, angiosperm hosts present several similarities, including modes of reproduction, resource acquisition and allocation, tissue development and architecture, hormone signaling and cell wall composition. It is therefore reasonable to suspect that microbes employ similar mechanisms for the manipulation of different angiosperm hosts. However, plant–microbe interactions are present throughout the plant kingdom and are represented in the fossil record , which dJungermanniaceae) which develop photosynthetically active leaf-like appendages that emanate from a stem (or gametophore) in addition to a below-ground axis with root hair-like rhizoids that acquire nutrients and water from the substrate  located on the ventral surface of certain liverworts (Blasia and Caviculara), and are also observed growing endo- or epiphytically on moss leaves . Bryophyte–bacterial symbioses are largely represented by interactions with nitrogen-fixing cyanobacteria that are most prevalent in hornworts. Colonies of the cyanobacterium s leaves . Interacs leaves . Severals leaves . The coleaves , oomycetes (Pythium) or bacteria (Pectobacterium), which colonize and degrade the leaves, stems and rhizoids of mosses (Phytophthora (P. infestans and P. capsici) and Colletotrichum gloeosporioides in protonemal (young differentiating gametophytes) or leaf cells of P. patens  in Antarctica alongside additional soil-borne fungi  that could potentially affect plant health  on liverwort thalli while Erysiphe trifoliorum structures are destroyed  colonize air chambers of the dorsal photosynthetic layer and are sometimes associated with ventral epidermal cells and rhizoids, but not within the central storage region (R. irregularis (green) are observed in rhizoids and within the central storage region of the thallus where arbuscules are formed . Additional aspects of the MAMP-triggered immunity (MTI) response appear to be conserved in bryophytes, based on observations that moss infected with fungi and oomycetes accumulate ROS species such as hydrogen peroxide and superoxide anions, up-regulate the PAL  and CHS  defense genes, and undergo cell wall reinforcement as described above (P. patens (PAL) are induced in pathogen-treated moss -like responses are conserved in bryophytes. Localized Pythium infections and MAMP treatments in A. serpens gametophytes provided enhanced resistance to subsequent infections in distal parts of the same gametophyte (A. serpens probably requires cell–cell (symplastic), apoplastic (extracellular) or volatile-mediated immune signaling between adjacent tissues. This form of systemic immunity appears to be mechanistically different from the traditional SAR responses in Arabidopsis thaliana and Nicotiana tabacum that rely on phloem-mediated long-distance signaling. Rather, the SAR-like response in moss appears similar to ‘adjacent’ resistance responses in barley, where infection in one part of a leaf enhances resistance to subsequent infections in distal parts of the same leaf  and a hornwort (Phaeoceros laevis) complement the mycorrhizal defect in the Medicago truncatula dmi3 mutant , GRAS transcription factor genes  and downstream components important for symbiosis . Transcriptome analysis of liverworts (L. cruciata) colonized by the AM fungus R. irregularis demonstrated that many of these genes are up-regulated during symbiosis, including non-orthologous copies of a symbiosis-inducible H+-ATPase and phosphate transporters  thalli overlaps strong with those expressed during the colonization of monocot and dicot roots (Anthoceros) and liverworts (Blasia) produce heat-labile chemical signals to attract free-living N. punctiforme cyanobacteria  into host cells is similarly employed by symbiotic rhizobacteria  transcription factor  of host tissues. Such molecules are termed effectors, as they have been demonstrated to interact with host machinery to promote colonization . Symbiotbacteria . Filamenbacteria . Extensibacteria . In soment cells . Moreovent cells , which ant cells . The SP7n factor . Finally. fulvum , in addiignaling .A. thaliana targeted by bacterial (Pseudomonas syringae), oomycete  and fungal (Golovinomyces orontti) effectors  receptor proteins that recognize cognate effector proteins to induce a robust defense response known as effector-triggered immunity (ETI). This response is generally believed to include a strong and sustained induction of basal defense components and the hypersensitive response (HR), a form of programmed cell death that acts to limit pathogen ingress at the site of infection . The acte domain . In compe domain . How, ane domain . This maP. carotovorum culture filtrate, which is thought to be enriched in cell wall-degrading enzymes and bacterial elicitors, induces moss immunity as demonstrated by the activation of cell wall reinforcement, defense gene expression, programmed cell death and the accumulation of OPDA  that are typical of plant–microbe interactions. DAMPs are liberated during the degradation of host cell walls and cuticles, and are also produced by the proteolytic processing of endogenous pro-hormone polypeptides . Mechani of OPDA . Moreove. patens , which h. patens . Auxin i. patens . Given t. patens .P. patens and M. polymorpha have already shown promise in molecular plant–microbe research, given their amenability to standard molecular biology techniques and relative ease of genetic manipulation (The literature discussed in this review demonstrates the diverse range of microbes that interact with bryophytes. Several studies describe conserved host responses to colonization, including cell wall reinforcement, ROS accumulation, phytohormone signaling and defense/symbiosis-related gene expression. Key components of angiosperm symbiosis and defense programs appear to be conserved in bryophytes, which suggests that these programs were first established in early land plant lineages. However, the limited data on bryophyte–microbe interactions have provided only a surface-level understanding of the important evolutionary aspects of symbiosis and immunity in land plants. Further exploration of early diverging land plant lineages is therefore required to address this gap in knowledge, and bryophytes present as ideal candidates given their position as extant descendants of the first plants to have colonized land. Models such as pulation . Moreovepulation , which wThe Schornack group is funded by the Gatsby Charitable Foundation [RG62472]; the Royal Society [RG69135]; the BBSRC OpenPlant initiative [BB/L014130/1]; and the Natural Environment Research Council .


Myocardial infarction is a leading cause of morbidity and mortality worldwide. Although medical and surgical treatments can significantly improve patient outcomes, no treatment currently available is able to generate new contractile tissue or reverse ischemic myocardium. Driven by the recent/novel understanding that regenerative processes do exist in the myocardium—tissue previously thought not to possess regenerative properties—the use of stem cells has emerged as a promising therapeutic approach with high expectations. The literature describes the use of cells from various sources, categorizing them as either embryonic, induced pluripotent, or adult/tissue stem cells . Many publications show the successful use of these cells to regenerate damaged myocardium in both animal and human models; however, more studies are needed to directly compare cells of various origins in efforts to draw conclusions on the ideal source. Although numerous challenges exist in this developing area of research and clinical practice, prospects are encouraging. The following aims to provide a concise review outlining the different types of stem cells used in patients after myocardial infarction. Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, with acute myocardial infarction (AMI) representing the most common CVD . CoronarTherefore, driven by the relatively novel understanding that regenerative processes do exist in the myocardium—tissue previously thought to be post-mitotic—the use of stem cells has emerged as an encouraging therapeutic approach with high expectations for patients with limited/no other treatment options ,6.Stem cells have two distinct properties underlying their use in the field of regenerative medicine: their capacity for self-renewal, and their ability to differentiate into a variety of tissues (known as potency) . Cells cTo improve cardiac function, an ideal cell therapy should generate a new vascular network and new contractile tissue that can align and synchronize with existing heart tissue; in addition, cells must be able to differentiate into cardiac lineages , or act via paracrine mechanisms to promote regenerative processes . The optThe literature describes the use of numerous types of cells from various sources . Many publications show the successful use of these cells to regenerate damaged myocardium in both animal and human models; however, conflicting results exist, procedural characteristics lack standardization, and more studies are needed to directly compare cells in efforts to draw conclusions on the ideal source. Although numerous challenges exist in this developing area of research and clinical practice, prospects remain encouraging.The following review aims to provide a summary of the primary sources of stem cells used in the treatment of MI.A PubMed search was done using search terms such as “stem cell therapy for myocardial infarction”, “(stem cells) AND myocardial infarction”, “ AND myocardial infarction”, “(hematopoietic stem cells) AND myocardial infarction”, and “(induced pluripotent stem cells) AND myocardial infarction”. The secondary search strategy included cross-referencing articles from primary resources. Publication date was restricted to the last 5 years using the PubMed search parameters feature. No publication status restrictions were imposed. The first search was run on 16 December 2017, and the last search was run on 31 January 2018. Types of studies analyzed included reviews, systematic reviews, meta-analyses, and clinical trials reporting the use of stem cell therapy for myocardial infarctions. Language was restricted to publications in English.Skeletal myoblasts were the first cell type discovered to have potential for use in the treatment of CVD in both animals and humans . These pFollowing successful animal studies, the MAGIC study was the first clinical trial using myoblast stem cell transplantation . Table 1In 2001, it was first shown that there was potential for infarcted myocardium to be regenerated with the transplantation of bone-marrow-derived stem cells (BMSCs) . AutologAfter the first documented use, small phase I trials demonstrated the therapy to be feasible and safe ,17. EarlA 2012 review by the Cochrane Heart Group analyzed data from 33 clinical trials reporting on BMSC therapy post-AMI. Findings showed lasting improvement in LVEF in follow-up periods ranging from 12 to 61 months, although this did not translate to decreased morbidity/mortality .A 2017 systematic review outlines the timeline of developments in BMMNC therapy over the last 15 years . They reFollowing results of the REPAIR-AMI trial which showed improved LV function with intracoronary administration of BMMNCs post-AMI, the TIME, LateTIME, and SWISS-AMI trials were developed ,25,26. IOverall, results of trials using BMMNC therapy have been mixed. Although results from meta-analyses (including those mentioned above) have shown promising results, numerous clinical trials have not confirmed those conclusions.The inconsistency in outcomes from treatment with BMMNCs can be attributed to several factors. First, BMMNCs are a heterogeneous population, and it is thus difficult to determine which cell populations led to the clinical effects, or lack thereof. For example, some studies have demonstrated significant myocardial regeneration post-infarction with HSC treatment, and no effects with BMMNCs ,27. AddiA meta-analysis from Nowbar et al. reported on the degree of discrepancy in study outcomes by analyzing specific differences found throughout 49 clinical trials that used BMSCs for cardiac repair . The groPresently, the ongoing phase 3 BAMI trial (NCT01569178) is aiming to provide more conclusive data on the efficacy of BMMNC therapy in AMI. It is the largest trial to date, aiming to standardize cell collection, handling, and delivery methods. Researchers are aiming to determine if their therapeutic method can result in a 25% reduction in mortality, which is their primary endpoint. The trial is scheduled to conclude in fall 2019.In addition to the ongoing research into the effectiveness of BMMNC therapy, given cell heterogeneity, studies isolating subpopulations of BMSCs have also emerged. These include trials using CD34+/CD133+ progenitor cells from hematopoietic lineages, or MSCs ,37.HSCs are a population of blood-forming cells that exist in small amounts in the bone marrow, with estimations that only 1 in 10,000 marrow cells are hematopoietic . HoweverHSCs are characterized by the presence of surface markers CD34, CD45, CD133, and CD117 , and to date there have been a few initial clinical trials using bone-marrow-derived CD34+ or CD133+ cells ,39,40,41Though the primary source of HSCs is the bone marrow, CD34+ cells have also been found in other tissues including peripheral blood , and theMSCs are a non-hematopoietic population of bone marrow cells. They are multipotent—able to differentiate into a limited number of cell types of mesenchymal lineage, including osteocytes, chondrocytes, adipocytes, myocytes, and marrow stroma . MSCs arStudies have shown the ability of MSCs to engraft into host tissue, rapidly differentiate into vascular endothelial and cardiomyocyte-like cells, recruit endogenous stem cells, and improve LV function post-MI ,46,47,48Although results from initial studies have been encouraging, there remain challenges that must be overcome. First, post-transplant cell engraftment and survival rate is poor; this is hypothesized to be due to the hostile environment of the ischemic/infarcted cardiac tissue . Thus, fOther studies have suggested that perhaps the hypoxic environment of infarcted tissue induces expression and release of growth factors that support angiogenesis, trigger proliferation and migration of cardiac progenitors, and promote MSC differentiation into cardiomyocytes. Factors such as vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and insulin-like growth factor (IGF) have been implicated in the upregulation of cardiomyocyte genes to direct differentiation and promote other reparative processes ,54,55.Research into the use of MSCs is growing due to a couple of key properties. First, their ease of isolation, expansion, and in vitro genetic modification makes them promising therapy candidates . Next, tTheories as to the mechanisms of this immunotolerance include the MSCs being hypoimmunogenic, immunosuppressing the local environment, modulating the T-cell phenotype, and lacking or expressing low cell-surface major histocompatibility complex (MHC) antigens, contributing to decreased alloimmune response ,58. ThesAnother advantage of MSCs is their ease of isolation from numerous tissues. MSCs traditionally isolated from bone marrow have subsequently been isolated from adipose tissue (subcutaneous or cardiac), umbilical cord blood, Wharton’s Jelly, peripheral blood, placenta, and muscle ,47,59,60Adipose tissue comprises both adipocytes and a mononuclear cell population containing MSCs similar to bone-marrow-derived MSCs (BM-MSCs). Adipose tissue mesenchymal stem cells (ATMSCs) offer some advantages over BM-MSCs, whose harvest procedure is invasive and painful. ATMSCs offer a simpler extraction procedure with decreased pain, as well as higher yields given that the density of stem cells in adipose tissue is significantly higher than in bone marrow (5% versus 0.01%) .Studies have shown ATMSCs to differentiate into cardiomyocytes at a higher percentage than BM-MSCs, as well as demonstrating greater immunomodulatory effects, showing superior inhibitory effects on CD4+ and CD8+ T cell and natural killer (NK) cell activation, and suppression of B cells .Recently there have been a few clinical trials using ATMSCs for CVDs. MyStromalCell is a phase II trial evaluating the effect of VEGF  stimulated ATMSCs in patients with chronic IHD and refractory angina . The PreFollowing initial uses of ATMSCs extracted via liposuction from subcutaneous adipose tissue, it was hypothesized that cardiac adipose tissue mesenchymal stem cells (cATMSCs) might have an improved capacity to support cardiac homeostasis and tissue renewal. Studies have shown that cATMSCs extracted from the base of the heart and around the aortic root display an innate cardiac-like phenotype . A 2014 The main challenge in using these cells is the invasive harvesting procedure, and the fact that they are not readily available in comparison to non-cardiac adipose tissue stem cells. To date, cardiac adipose tissue biopsies have been obtained from patients who underwent cardiothoracic surgery prior to CABG. Additionally, typical donors tend to be older with various comorbidities that contribute to poor cell quality .However, these challenges have the potential to be overcome in the future. Since a significant number of routine cardiac interventions take place in most large centers, this opens the door for the possibility of these patients becoming donors. With little added risk to the planned procedure, cardiac adipose tissue biopsy can be obtained and contribute to creating an “off the shelf” bank of cATMSCs for use in patients post-MI .Wharton’s Jelly is a continuum of gelatinous mucous tissue in the umbilical cord whose role is to provide support/protection to umbilical vessels. Wharton’s jelly derived mesenchymal stem cells (WJMSCs) are a primitive population of multipotent stromal cells originating from embryonic and/or extraembryonic mesodermal tissue at day 13 of embryonic development ,66. WharIn 2015, the WJ-MSC-AMI trial presented results of the first study evaluating safety and efficacy of intracoronary allogeneic WJMSC transplantation in patients with ST-elevation MI (STEMI) . The triAdditionally, there were no signs of immune response, ectopic tissue, or tumor-associated antigens found after cell transplantation (even though they possess some embryonic stem cell markers), and their use is noncontroversial, highlighting the advantage of WJMSCs over induced pluripotent and embryonic stem cells (which will be discussed below) .Umbilical cord blood (UCB) has been considered the most abundant source of stem cells for numerous clinical purposes. Although previously used mainly in the treatment of hematological conditions, uses have expanded to effectively treat non-hematopoietic conditions as well . UmbilicUCB extraction is safe and painless, and UCBMSCs are readily isolated and expanded in vitro with short culture time (2 days), can be cryopreserved without the loss of immunoprivileged or regenerative properties, and represent an additional population of multipotent progenitor cells . There iOne of the more recent developments in the area of MSC therapy is the use of cardiopoietic MSCs. Cardiopoiesis is a process of conditioning that improves the regenerative ability of autologous stem cells via methods of lineage specification . The indn = 15), or a cell therapy group (n = 21) who received intramyocardial administration of bone-marrow-derived C3BS-CQR-1 cardiopoietic cells. Though primary endpoints were safety and feasibility measures rather than therapeutic effects, the treatment group showed improvements in LVEF, LVESV, and 6 minute walk test at a 6 month follow-up. Results showed the process to be as safe and feasible as non-lineage-guided BMSCs, with the addition of favorable effects on LVEF, remodeling, and overall patient wellness when compared with unguided BMSCs or standard clinical care.The C-CURE trial was the first study to employ the use of cardiopoietic cells to treat post-MI ischemic heart failure . ParticiFollowing these initial results from C-CURE, the CHART trial was designed to assess the therapeutic benefits of C3BS-CQR-1 cells in patients with chronic HF secondary to IHD, with the aim to validate cardiopoietic stem cell therapy . CHART rThese trials provide baseline research and insight that highlight the potential for a lineage-specified stem cell therapy without needing heart tissue itself as the cell source. This would be of significant clinical benefit given the challenges with obtaining cardiac stem cells, which will be further discussed below.Embryonic stem cells (ESCs) are a population of pluripotent cells that arise from the inner cell mass of the blastocyst during embryonic development in mammals. They can give rise to any/all adult cell types, and thus have the potential to regenerate lost myocardium .A primary advantage of ESC transplantation is in their capacity to differentiate into cardiomyocytes that are able to electrically integrate with cardiac muscle. For example, an early study in a swine model with AV block resulted in reversal of the block after human-ESC-derived cardiomyocytes were transplanted . FurtherAn initial challenge with ECS studies was achieving sufficient amounts of pure cell samples from heterogeneous cell populations . StrategThe first clinical use of human ESCs in cardiac patients took place in 2015. The ESCORT trial delivered ESC-derived cardiac progenitor cells to patients with advanced IHD while undergoing CABG or mitral valve procedures ,79. ExpaBesides presenting the first application of embryonic cells in human cardiac regenerative therapy, the technique for cell transfer offered additional novelties. Previously, cell transfer had been accomplished by transepicardial injections, or percutaneous intracoronary or endoventricular catheter-based administration. Advantages of the patch-based approach include improved cell retention and survival, decreased cellular damage, decreased risk of ventricular arrhythmias, and improved patient survival and heart function preservation .This initial human trial demonstrated technical feasibility and safety, thereby providing a foundation for the development of future trials that are adequately powered to evaluate efficacy . AlthougOther considerations in future research include the challenges precluding further use of ESCs in humans at this time, which involve ethical, political, and regulatory dilemmas. Though some nations such as the USA allow the research use of embryos discarded after in vitro fertilization procedures, strict laws in other nations prohibit such use .Prior to the last decade, the process of cellular differentiation was thought to be irreversible, an idea that was challenged in 2006 when researchers induced a pluripotent state in somatic cells . InducedAs a result of the ethical and availability issues associated with ESCs, the use of iPSCs has become of clinical relevance for cardiac regenerative therapy, and initial mice studies were soon followed by the generation of iPSCs from human fibroblasts ,85.To be of therapeutic benefit, human iPSCs must be able to either signal angiogenesis, or differentiate into cells of cardiac lineage, and various techniques similar to those in mice have been described . In vitrChallenges involved with iPSC therapy include developing efficient procedures for inducing pluripotency, developing alternatives to traditional viral delivery systems, and the potential for tumorigenesis ,90,91. RAlthough results from initial preclinical studies have shown successful outcomes on cardiac function, confirmation of in vivo safety and functionality is required prior to translation into clinical practice. Further research aims to focus on optimizing and creating standardized and reproducible differentiation techniques, and establishing clinical trials to confirm the safety and efficacy of published findings ,89,91.Although several forms of cell therapy have been beneficial to various degrees in improving cardiac function post-MI, they are not natural residents of cardiac tissue, and it is controversial as to whether they can truly regenerate lost myocardium . Cells oSince 2003, when Beltrami and colleagues  describeWhen compared with other adult SC types, CSCs have been shown to more efficiently express cardiac markers and more effectively differentiate into cardiomyocytes in in vitro as well as in vivo animal MI models . A 2016 An advantage of CSC, similar to that of MSCs, is in their immunomodulatory and immunosuppressive abilities. Studies have shown that human CDCs express MHC class I, but lack MHC class II antigens, as well as CD80/86 costimulatory molecules, avoiding immunologic rejection in both in vitro and in vivo animal models . MalliarIn another study aiming to analyze the mechanisms underlying the immunologic properties of human cardiac progenitor cells (hCPCs), authors concluded that they possess a weak immunologic profile, with programmed death ligand-1 (PD-L1) responsible for the immunomodulation . AuthorsIn humans, studies have tested the use of c-kit+ and CDCs, and initial clinical trial results have been encouraging. The SCIPIO phase I clinical trial showed improved LVEF and decreased infarct size at 4 and 12 month follow-ups post intracoronary administration of autologous c-kit + CSCs in ischemic cardiomyopathy patients undergoing CABG . In the Challenges in using CSCs include an invasive isolation procedure, the need for costly pre-transplant ex vivo expansion to obtain adequate cell numbers for injection, and low availability . To overSince the study of CSCs is more recent than that of other stem cell sources, further analysis is needed in order to characterize cell types in terms of their surface markers, gene expression, differentiation capacities, and role in cardiac repair/homeostasis prior to further clinical application . First, The discrepancies and variety in results found to date reflect the ongoing research focus, the challenges that exist in this emerging field, and the obstacles that must be overcome in order for the use of stem cell therapy in cardiovascular medicine to realize its potential.Review articles have previously outlined in detail the factors that have contributed to the spectrum of outcomes thus far ,15. In 2Future research methodologies should aim to develop more standardized techniques so that results are comparable, and further clinical trials are needed in order to validate and build on previous findings. Following these improvements, studies that directly compare amongst/between various types of stem cells would contribute to determining the ideal source of stem cells for use in cardiac regenerative medicine. Finally, concepts of improving donor cell accessibility and developing “off-the-shelf” stem cell products should continue to be pursued, aiming to realize the potential of creating a product for convenient and timely use which will be of great clinical benefit.


Zika virus infection has recently attracted the attention of medical community. While clinical manifestations of the infection in adult cases are not severe and disease is not associated with high mortality rates, Zika virus infection can have an impact on fetal development and lead to severe neurodevelopmental abnormalities.To gain insight into different aspects of Zika virus infection, a comprehensive literature review was performed. With regard to epidemiology and geographical distribution of Zika virus infection, relevant information was extracted from CDC and WHO websites.In this review, we discuss different basic and clinical aspects of Zika virus infection including virology, epidemiology and pathogenesis of disease. Laboratory methods required for the diagnosis of disease together with ethical issues associated with Zika virus infection will also be discussed in detail.Herein, we have tried to provide a multi-faceted view of Zika virus infection, with greater emphasis on disease status in Eastern Mediterranean Region. Flaviviruses are responsible for several important human diseases including Dengue, West Nile and Yellow fevers, Japanese encephalitis, Tick-borne encephalitis, and Zika fever. The major route of transmission for most Flaviviruses is through arthropod vectors and central nervous system injury and hemorrhagic fevers represent major clinical outcomes. In recent years, Zika virus infections have attracted the attention of international medical community, chiefly because of their role in causing microcephaly and other neurodevelopmental abnormalities which occur as a consequence of maternal infections .Zika virus was first isolated in 1947 in the Zika forest in Uganda from a rhesus macaque . SerologIn this review, we have discussed the current knowledge about various aspects of Zika virus infection and recent developments including antiviral treatments for this infection. The first four sections of this review cover virology, epidemiology, pathogenesis, and laboratory diagnosis of Zika virus infection. While Zika virus infection is a global concern, in the epidemiology section we have put some more emphasis on findings from Eastern Mediterranean Region (EMRO) countries. Considering the ethical considerations related to feto-maternal and neurodevelopmental dimensions of the Zika virus infection, the final section of this review provides a detailed account of ethical aspects of Zika virus infection .Flaviviridae family of viruses , the capsid (C) and the precursor of the membrane (prM)) and seven nonstructural proteins  . The ssRFlaviviridae family despite significant differences in tissue tropism, transmission, and pathogenesis , ZINC33683341 and ZINC49605556 (both in silico designed) has been proposed. The other approaches include the inhibition of endosomal fusion using compounds that reduce the acidity of endolysosomal vesicles like chloroquine  and disrupting the electrostatic interaction between cell and virus membrane using squalamine  .Flaviviridae, antiviral agents targeted their helicase could also be used for the Zika virus  is a RdRP inhibitor approved by FDA for chronic HCV treatment. It also inhibits Zika virus replication –17. Zikaka virus . Likewiska virus  as well.Despite the many studies done on Zika antiviral treatments, so far no FDA approved category A drug has been found safe to use in mothers and fetuses .Before the first large outbreak of Zika virus infection on Yap Island, Federated States of Micronesia , only spAn increased incidence of cases of the Guillain– Barré syndrome (GBS) was reported after a larger epidemic of Zika virus infection in French Polynesia in 2013 . In 2014In early 2015, several cases presenting a “dengue-like syndrome” investigated in Brazil (a non-Dengue virus and non-Chikungunya virus infection) and Zika virus was detected by reverse transcription polymerase chain reaction (RT-PCR) assay and confirmed by DNA sequencing , 26. TheOn Jul 2015, in the State of Bahía, Brazil, an increase in the number of Guillain-Barré cases in which half of them had reported symptoms consistent with Zika virus infection .In Jan 2016, an unusually significant increase of GBS was reported in El Salvador. An Emergency Committee was convened by the Director-General of WHO, under the International Health Regulations (2005) on 1 Feb 2016, and finally announced “the recent cluster of microcephaly and other neurologic disorders reported in Brazil to be a PHEIC .Aedes mosquitoes: Djibouti, Egypt, Oman, Pakistan, Saudi Arabia, Somalia, Sudan and Yemen. Some of these countries are particularly vulnerable to emerging of Zika virus, because of the fragility of health systems, weakness of disease surveillance systems, the inadequacy of response capacities, and a suboptimal level of public health preparedness Content source: Centers for Disease Control and Prevention, Sep 2018 updated.  . In vitrFollowing cell entry, Zika virus induces strong interferon responses in infected cells. Studies on Zika virus-infected human primary fibroblasts have shown strong upregulation of interferon-beta transcripts 24 to 48 h after infection . A mildeProductive infection of dermal fibroblasts and dendritic cells together with insufficient control of infection by innate and adaptive immune mechanisms usually leads to Zika virus viremia, which underlies the non-specific clinical symptoms which might last for a few days. In a pregnant woman, maternal viremia might lead to fetal viremia. It is not well known how the virus is transmitted to developing nervous system following the establishment of fetal viremia. While in circulation, Zika virus can infect fetal monocytes and these monocytes can carry the infection to the developing nervous system. Studies on fetal brain tissue derived from Zika virus-infected mothers who have undergone abortion have shown viral particles in neural cells, indicating that the virus can proliferate inside neural cells in a developing brain . While iDepending on the purpose of the investigation, laboratory diagnosis of Zika virus can be conducted by virus isolation, antigen detection, viral RNA detection with molecular assays and anti-Zika virus antibodies detection with serological assays .The first isolation of Zika virus was performed by intracerebral mouse inoculation considered as the reference assay for arboviruses isolation , 36. AmoAntigen detection is a valuable assay to approved Zika virus infection in autopsy tissues. Using immunohistochemistry (IHC) technique, Zika virus antigen has been detected in brain and placental tissues from congenitally infected newborns with microcephaly and miscarriages , 42. RecZika virus RNA is detectable in different types of body fluids such as blood (serum or plasma) –50, urinReverse transcriptase PCR (RT-PCR) is highly sensitive and specific and known as the “gold standard” for ZIKV diagnosis . RegardiMolecular diagnosis of Zika virus infection in human usually performs on plasma or serum specimens within the first week after onset of clinical symptoms . AlthougDespite the fact that the molecular diagnosis possesses high sensitivity and specificity, short period of viremia can negatively affect the Zika virus RNA detection . TherefoDetection of anti-Zika virus antibodies can be performed by different serological tests including complement fixation, haemagglutination inhibition, immunofluorescence (IF) assay, ELISA and neutralization tests , 35. TypSo far there is no FDA approved a serological test for Zika virus. However, FDA has authorized the use of five serological assays with emergency use authorization for detection of anti-Zika virus IgM antibody including IgM antibody capture ELISA (Zika MAC-ELISA) (CDC) , ZIKV DeBecause of cross-reactivity with other Flaviviruses such as dengue and yellow fever viruses, and the possibility of nonspecific reactivity, results of IgM detection assays should be interpreted with caution and positive or equivocal results must be confirmed by plaque-reduction neutralization testing (PRNT) .Zika virus has been classified as a risk group 2 human pathogen. Therefore, diagnostic laboratory tests should be performed in a Biosafety Level 2 (BSL-2) facility . The virAddressing ethical questions and moral conflicts of Zika virus infection may be essential to develop a comprehensive approach to control this public health crisis . TherefoNational and international health authorities should observe the principle of veracity, by clear and transparent informing system for raising the public awareness regarding the real situation . At the The fear raised from high probability of congenital problems, mainly microcephaly, of neonates delivered by mothers with Zika virus infection in their first trimester of pregnancy , puts abTogether with Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), Zika virus infection qualifies as a “newly emerging” infectious disease, with the potential to cause serious public health issues. Unlike the other “newly emerging” infections which can lead to severe morbidity and mortality in infected adults or pediatric hosts, Zika infection does not pose a significant threat to infected adults and its risk is more due to the potential to cause fetal abnormalities, provided that the infection occurs during pregnancy. Indeed, among the four recent PHEIC declarations by WHO , Zika is unique in the sense that it is a member of the TORCH group of infections; i.e. the group of pathogens with the ability to lead to congenital infections/anomalies. This might influence both disease prevention and management strategies as well as raising ethical and sociological issues. Thus, increased awareness of the medical community together with improvements in vector control and disease surveillance systems are of utmost importance for controlling any potential Zika virus-related threats in different countries.Ethical issues  have been completely observed by the authors.


Multiple sclerosis (MS) is a complex chronic inflammatory and degenerative disorder of the central nervous system. Accelerated brain volume loss, or also termed atrophy, is currently emerging as a popular imaging marker of neurodegeneration in affected patients, but, unfortunately, can only be reliably interpreted at the time when irreversible tissue damage likely has already occurred. Timing of treatment decisions based on brain atrophy may therefore be viewed as suboptimal.This Narrative Review focuses on alternative techniques with the potential of detecting neurodegenerative events in the brain of subjects with MS prior to the atrophic stage. First, metabolic and molecular imaging provide the opportunity to identify early subcellular changes associated with energy dysfunction, which is an assumed core mechanism of axonal degeneration in MS. Second, cerebral hypoperfusion has been observed throughout the entire clinical spectrum of the disorder but it remains an open question whether this serves as an alternative marker of reduced metabolic activity, or exists as an independent contributing process, mediated by endothelin-1 hyperexpression. Third, both metabolic and perfusion alterations may lead to repercussions at the level of network performance and structural connectivity, respectively assessable by functional and diffusion tensor imaging. Fourth and finally, elevated body fluid levels of neurofilaments are gaining interest as a biochemical mirror of axonal damage in a wide range of neurological conditions, with early rises in patients with MS appearing to be predictive of future brain atrophy.Recent findings from the fields of advanced neuroradiology and neurochemistry provide the promising prospect of demonstrating degenerative brain pathology in patients with MS before atrophy has installed. Although the overall level of evidence on the presented topic is still preliminary, this Review may pave the way for further longitudinal and multimodal studies exploring the relationships between the abovementioned measures, possibly leading to novel insights in early disease mechanisms and therapeutic intervention strategies. Multiple sclerosis (MS) is a chronic inflammatory demyelinating and degenerative disorder of the central nervous system (CNS) affecting over 2.5 million people worldwide. The first symptoms usually occur during young adulthood, after which patients may experience a heterogeneous relapsing or progressive disease course with a modulating role for age, sex and comorbidities –5. CliniThe therapeutic landscape of MS is changing dramatically since the past 10 to 15 years ,  which relies on radioligands selectively binding to the proteins of interest. Metabolic imaging techniques, in turn, exploit the magnetic properties of atomic nuclei, such as protons or sodium ions. The idea that early neurodegenerative MS pathology can be captured in the absence of atrophy is thus far best supported by magnetic resonance spectroscopy (MRS), sodium imaging, chemical exchange saturation transfer (CEST) and PET findings.1H-MRS and are usually expressed as NAA/creatine ratios for reasons of stability [N-acetyl-aspartate (NAA) is almost exclusively produced by neuronal mitochondria in mature CNS and figures as a marker of mitochondrial function and/or integrity in both white and grey matter , 49. Thetability , 50, 51.tability , 53. In tability . MRS stutability –57.Definite proof that a chronic NAA reduction unequivocally precedes brain atrophy in a longitudinal neurodegenerative scenario affecting patients with MS, and which is detectable within this context by MRS, is still lacking, but at least a few interesting findings can be extracted from the current literature.First, MRS follow-up studies of acute lesions in the brain and spinal cord have demonstrated that reduced NAA, albeit not necessarily a return to normal, partially recovered over time , 58, 59.23Na MRI, based on which several groups have found increased concentrations within plaques, normal-appearing white matter and cortical and deep grey matter of subjects with MS, as compared to controls [23Na MRI and MRS analysis, sodium accumulation was directly associated with neuronal metabolic dysfunction, as reflected by decreased NAA levels, in focal lesions, grey matter and normal-appearing white matter of 21 individuals with relapsing-remitting MS. [Intraneuronal sodium accumulation is an early transduction of energy dysfunction in our proposed cascade of neurodegenerative events in MS. Under normal physiological circumstances, CNS sodium concentrations are actively kept low in the intracellular compartment (tissue fraction 80%), as compared to those in the smaller extracellular counterpart (20%) , in ordecontrols –71. Highcontrols . In a coting MS. 23Na MRI study enabling the quantification of the intracellular sodium concentration and extracellular sodium fraction, an indirect measure of the extracellular sodium concentration. They reported an increase of both total and intracellular sodium levels in the grey and normal-appearing white matter of 19 patients with relapsing-remitting MS, as compared to healthy controls, whereas extracellular sodium fractions in fact were reduced, arguing against the simultaneous presence of atrophy [The abovementioned studies are somewhat limited by the fact that they have assessed total sodium concentrations without distinguishing between the intra- and extracellular fraction, and theoretically, it cannot be excluded that an augmentation of total levels is predominantly driven by expansion of the extracellular space, in parallel with neuronal atrophy. However, abnormally high sodium concentrations were also found in grey matter zones which were spared by atrophy in progressive MS , as well atrophy . Interes atrophy , while a atrophy .CEST allows to image compounds at concentrations that are too low to be detected using standard MRI. The technique is based on the exchange of protons between specific tissues, that are first saturated, and water . One of MS is multifactorial disorder in which many different radioligands can be used for experimental PET imaging purposes, depending on whether the biological process of interest is inflammation, myelin breakdown, neuronal degeneration or astrocyte activation . One of 11C-flumazenil is a different PET radioligand with selectivity for the benzodiazepine site of the class A gamma-aminobutyric acid (GABA) receptor complex in synapses of grey matter neurons. Freeman and co-workers found a reduced cortical 11C-flumazenil binding in a mixture of patients with relapsing-remitting and secondary progressive MS, as compared to healthy controls. Interestingly, this effect was already noticeable in the subset of relapsing-remitting subjects, who did not have a significant degree of grey matter atrophy, and was globally associated with reduced information processing speed [ng speed . Cao andng speed . If and 11C-PK11195 have demonstrated increased uptake in active lesions, as well as in normal-appearing white and cortical grey matter, correlating with disability and brain atrophy measures [11C-PBR28, have been developed to improve affinity and specificity of the receptor binding and, interestingly, microglial activation was associated with brain volume loss at the cross-sectional and longitudinal level  in two recent studies using this compound [Microglia are local macrophage residents that, together with infiltrating blood-derived monocytic cells, play a key role in regulating CNS inflammation. In MS, microglial activation may contribute to both tissue damage, mainly through the production of oxidative agents –89, and measures –93. Secocompound , 95.Cerebral blood flow (CBF) is the most commonly used numerical expression of cerebral perfusion and represents the volume of blood flowing through a given amount of brain tissue per time unit . As blooThe exact underlying mechanism and pathophysiological significance of reduced brain perfusion in MS remain poorly understood at present. Somewhat surprisingly, Saindane and co-workers concluded that perfusion and diffusion tensor MRI properties of the normal-appearing corpus callosum were compatible with primary ischemia in relapsing-remitting patients, rather than with hypoperfusion secondary to impaired axonal integrity . This thThe idea that brain hypoperfusion precedes or even induces neurodegenerative changes in MS, is currently still speculative yet intriguing. Some pathological data do support a theoretical framework for this type of ‘reverse causality’ between both. Enhanced expression of hypoxia-inducible factor (HIF)-1α and its downstream genes, a universal salvage pathway that becomes activated in response to tissue hypoxia, has been observed in post-mortem normal-appearing white matter of patients with MS.  CerebralProspective longitudinal imaging data are missing but several cross-sectional analyses have already suggested the presence of a functionally relevant hypoperfusion in non-atrophic brain regions of subjects with MS. Hence, Debernard and co-workers have found a global perfusion reduction in the cerebral cortex and deep grey matter of patients with early relapsing-remitting MS, compared to controls, in the absence of corresponding volume loss. This CBF reduction was positively correlated with objective memory disturbances . A similSome neurological functions are organized in a way that focal damage can cause very straightforward clinical impairment. For example, a single lesion in the middle temporal visual area, which is involved in the perception of motion, may lead to motion blindness . Other fFunctional MRI (fMRI) detects brain activity by measuring changes in CBF as a surrogate parameter, supported by the principle that regional perfusion and neuronal activation are coupled . Blood oThe most primary application of fMRI explores BOLD responses during specific tasks or stimuli. Increased zones of activation while performing motor or cognitive exercises have been consistently demonstrated in patients with MS, as compared to healthy controls , 126. ThDiffusion tensor imaging (DTI) is a specific form of diffusion-weighted MRI that allows tracking of water molecules through biological tissues . In a meIn a 2 year follow-up study of 37 CIS patients, Rocca and colleagues observed a distributed pattern of increased white matter diffusivity at baseline (2-60 days after diagnosis), which remained stable for one year but resulted in a further increase at 24 months. In the same study, an early increase in grey matter volume of the bilateral middle and inferior temporal gyri was noted at baseline, followed by a further increase in several grey matter structures at 3 months and a volume decrease of the deep nuclei, cerebellar cortex and several cortical areas from month 12 onwards . WhereasThe growing presence of DTI in MS research can additionally be illustrated by studies demonstrating pharmaceutical effects on diffusion parameters. In a recent longitudinal observation, a relatively stable pattern in diffusion metrics was encountered in patients with relapsing-remitting MS which were administered dimethyl fumarate (DMF). In the same study, healthy controls showed a significantly greater rate of diffusion parameters increase in the thalamus and normal-appearing white matter, compared to the subjects with MS , cautiouAlthough numerous contenders have been piloted over the past decades, only two body fluid markers are currently being used in routine MS practice: i.e. the presence of oligoclonal bands (OCBs) and an elevated IgG index, both in the cerebrospinal fluid (CSF). Both are helpful in establishing the diagnosis, and the former has showed potential as an independent predictor of conversion to MS in CIS and RIS subjects , but oveNeuro-axonal damage is the pathological substrate of disability in a large scale of neurological diseases. Elevated neurofilament concentrations have been found in the serum and CSF of patients with MS, but also in individuals with traumatic, vascular and other degenerative conditions of the CNS . In MS, Returning to the crux question of this paper, we are not aware of studies demonstrating elevated body fluid neurofilament levels in patients with MS, as a result of neuronal homeostasis disruption and in the objectivated absence of brain atrophy. Nf-L values were found to be increased in the serum of subjects with a CIS , where lDespite the growing availability of efficacious disease-controlling therapy, MS remains a significant burden for global health. Accelerated BV loss has recently emerged as a popular imaging biomarker of neurodegeneration, which is considered to be the main determinant of long-term prognosis in affected individuals. Unfortunately, irreversible tissue damage is already likely at the time when brain atrophy can be reliably measured. This Review highlights potential neurodegenerative markers, that may precede these atrophic changes and, Figure  thereforThe statements and assumptions throughout this paper are not without limitations. First, definite proof for the proposed model linking inflammation to neurodegeneration in MS is, although plausible and frequently put forth in the literature, still lacking and therefore our basis remains hypothetical. MS is an extremely complex disease in which many other pathways may lead to neurodegeneration and atrophy, including primary deficits in neurons, oligodendrocytes or astrocytes –172. ButStudies exploring BV in combination with metabolic or molecular MRI, perfusion assessment, connectivity analysis and/or neurofilament measurement are scarce but should guide new work in this field. Thus far, only CBF and DTI alterations have been directly evaluated against brain volumetry, and provide the highest level of evidence. In order to disentangle the different possible mechanisms leading to atrophy and their timelines, longitudinal and multimodal studies are required. Studies of particular interest would be to explore the longitudinal relationship between glutamate, NAA and BV, to investigate the hypothesized U-shaped curve of functional MRI connectivity, and to investigate whether metabolic dysfunction induces a reduced cerebral blood flow or the other way around. These studies could provide important novel insights in disease mechanisms and provide new pathways to counteract the neurodegenerative effects of MS before irreparable damage has occurred. Finally, it is worth noting that with the advent of big medical data and artificial intelligence (AI) techniques, new models can be generated that may be able to predict atrophy before irreversible tissue loss has set in. Yet, AI requires a huge amount of data that is currently unavailable for most of the modalities presented in this paper. A specific (imaging) modality should first have some clinical value before large datasets can be collected. Based on the current literature, we only found one study that applied a deep learning strategy to uncover sustained EDSS progression , that re


Going through a divorce is one of the most stressful life events across the life course with far-reaching ripple effects for individuals’ physical, mental, and often financial well-being. For some individuals, however, coping with marital dissolution and adapting to new social roles may lead to considerable gains in their reorientation in life and stimulate their personal development. This is captured in the concept of personal growth, which has been studied primarily in the context of becoming widowed, and through a cross-sectional lens. In our study, we track trajectories of personal growth after ending a long-term marriage of at least 15 years. We focus on divorce among adults in their second half of life because rates of grey divorce have been on the rise since the 1980s, yet longitudinal research on personal growth after marital dissolution remains sparse. We further examine whether trajectories of personal growth vary by gender, SES, reasons of divorce , and social support. Data stem from a Swiss panel on intimate relationships and marital dissolution among long-term married individuals conducted between 2012 and 2016 (N = 530). Random-effects group-specific growth curve models yielded similar—and slightly decreasing—trajectories of personal growth for divorced women and men over time. However, highly significant gender differences indicated that women showed higher levels of personal growth over the whole observation period. Because gender differences seemed to be fueled by social capital rather than economic assets, we discuss these results through the lens of a linked-lives perspective.


There is significant variability in the preparedness of incoming interns at the start of residency training with regard to medical knowledge, procedural skills, and attitudes. Specialty-specific preparatory courses aimed at improving clinical skills exist; however, no preparatory courses targeting wellness promotion or burnout prevention have previously been described. Resident well-being has gained increasing attention from the Accreditation Council for Graduate Medical Education, and numerous studies have demonstrated high levels of burnout among resident physicians. The American Medical Association (AMA) divides resident well-being into the following six categories: nutrition, fitness, emotional health, financial health, preventative care, and mindset and behavioral adaptability. Using the AMA’s conceptual framework for well-being in residency, we performed a targeted needs assessment to support the development of a “pre-residency” well-being curriculum. Our aim was to discover what current residents and faculty felt were the perceived areas of under-preparedness, in relation to resident well-being, for incoming interns at the start of their residency training.Using a grounded theory approach, we conducted a series of semi-structured, focus group interviews. Focus groups consisted of junior residents (postgraduate years [PGY] 1-3), senior residents (PGY-4), and current faculty members. A standardized interview guide was used to prompt discussion and themes were identified from audio recording. We modified theories based on latent and manifest content analysis, and we performed member checking and an external audit to improve validity.Participants noted variable exposure to both formal and informal well-being training prior to residency. Regardless, participants uniformly agreed that their past experiences did not adequately prepare them for the challenges, specific to burnout prevention, faced during residency training. Of the six domains of resident well-being described by the AMA, emotional health, mindset and behavioral adaptability, and financial health were the domains most cited for interns to be underprepared for at the start of residency training.Despite variability in prior medical school and life experiences, incoming interns were underprepared in several domains of well-being, including emotional health, mindset and behavioral adaptability, and financial health. Targeted interventions toward these areas of well-being should be piloted and studied further for their potential to mitigate effects of burnout among resident physicians. There is significant variability in the preparedness of incoming interns at the start of residency training in terms of medical knowledge, technical skills, professional skills, and attitudes.4Resident well-being has gained increasing attention from the Accreditation Council for Graduate Medical Education (ACGME),Using a grounded theory approach,We used a convenience sample of junior residents (postgraduate years [PGY] 1-3), senior residents (PGY-4), and current faculty members to generate three focus groups. Recruitment was performed through a series of emails and announcements at didactic conference. The junior resident focus group consisted of one PGY-3 resident, one PGY-2 resident, and four PGY-1 residents. The senior resident focus group consisted of seven PGY-4 residents. The faculty focus group consisted of eight faculty members. Interview data were audio-recorded and collected in a private conference room within the hospital. The study authors each independently conducted a separate focus group using a standardized interview guide . To estaWhat do we already know about this issue?Little data exist regarding well-being preparedness among incoming emergency medicine interns.What was the research question?What are the perceived areas of under-preparedness, related to resident well-being, for interns beginning residency?What was the major finding of the study?Interns were underprepared in several domains of well-being, including emotional health, mindset and behavioral adaptability, and financial health.How does this improve population health?It provides a needs assessment for future pre-residency well-being curricula.As the study authors served as individual focus-group facilitators, it is important to note their individual qualifications, as focus group facilitation requires an important set of skills.Non-verbatim transcription and coding was manually performed by the primary author directly from the audio recordings. Given the relatively small volume of focus-group content, the decision was made to forego the use of full-transcription software services, and rather focus on selective manual transcription and coding directly from the audio files, to better capture not only what interviewees were saying but also how they were saying it.Participants noted variable exposure to both formal and informal well-being training prior to residency training. Some participants received training during medical school, while others gained knowledge from prior life experiences. Training in medical school varied from longitudinal curricula that spanned the course of a semester to occasional lectures dispersed throughout the four years. Prior experiences that participants noted as preventative toward burnout included involvement in sports and regular exercise, adequate sleep and nutrition, yoga and meditative practices, and maintaining the activities or interests that formed one’s individual identity prior to residency training. Additionally, engagement through social interactivity, peer bonding, and mentorship were noted to be beneficial in promoting wellness and preventing burnout.Regardless of past experiences, participants agreed that their past experiences did not adequately prepare them for the challenges specific to burnout prevention faced during residency training. For some, it was not a lack of knowledge regarding specific well-being domains , but the inability to apply their knowledge given the extrinsic challenges faced in residency training .Of the six domains of resident well-being described by the AMA, emotional health, mindset and behavioral adaptability, and financial health were the domains most cited for interns to be underprepared for at the start of residency training. Participants noted that interns were unprepared to deal with the emotional exhaustion, the psychological burden of increased responsibility, and the ability to manage their self-doubt and feelings of imposter syndrome. In addition, interns were ill-equipped to manage their time effectively, both in terms of balancing clinical responsibilities with studying as well as achieving a healthy work-life balance. Participants felt that incoming interns were most knowledgeable with regard to fitness, nutrition, and preventative health, although the translation of this knowledge to practice was difficult given the time constraints and clinical workload of residency training.the number one source of anxiety and frustration” in his life, while another participant commented that of the aforementioned categories, her lack of financial understanding contributed the least to her “emotional devastation.”The majority of participants acknowledged that incoming interns  had complete financial illiteracy in terms of their ability to manage debt, plan for retirement, budget, and invest. Opinions varied in how much financial illiteracy contributed to personal stress and burnout with one participant stating that it was “While common themes emerged from the content analysis, sub-themes existed between the three demographically selected focus groups . Junior residents commented on feelings of emotional exhaustion, difficulties with time management, and trouble dealing with both the psychological burden of increased clinical responsibility and feelings of self-doubt. Meanwhile senior residents noted difficulties with compassion fatigue, the cumulative psychological effects of having to constantly cope with tragedy, and their limited ability to self-identify symptoms of burnout. Faculty provided additional commentary, noting the psychological burdens of clinical documentation, the isolation from family and friends experienced during residency training, and the neglect of on-shift nutrition, all of which contribute to increased resident burnout.Incoming interns were underprepared for residency training with regard to several aspects of well-being including emotional health, financial health, and mindset and behavioral adaptability. Regardless of prior well-being training in medical school or past life experiences, focus group participants voiced both a need and a demand for a longitudinal well-being curriculum. We postulate that an opportune time to implement such a curriculum could be in the two-three month window between when medical students match into their chosen specialty and they begin their internship. This period of time has been described as having significant variability and questionable benefit to learners.The variability in responses between demographically separated focus groups suggests that the various elements of burnout affect physicians differently dependent on their level of training. Although this study was not designed to look at this phenomenon, intuitively it makes sense. As the most novice physicians in the emergency department, interns may inherently feel overwhelmed and emotionally exhausted. As residency progresses, feelings of emotional exhaustion and self-doubt may improve as more junior learners arrive, only to be replaced by compassion fatigue and depersonalization as the demanding training schedule progresses.There were several notable limitations to this study. The study was conducted at a single residency program and limited additional demographic information was obtained from study participants, which limits its generalizability, although participants attended different medical schools and had a vast array of prior life experiences. We performed convenience sampling, as opposed to purposive sampling, due to limited group availability given clinical schedules. The sample size was relatively small, decreasing the statistical power of the study; additionally, the distribution of residents across focus groups (PGY 1-3 residents and PGY-4 residents as two separate groups) allowed for potential acquiescence bias within the former group. The groups were created in this manner to preserve equal numbers of focus-group participants across the study. However, the actual study population was relatively skewed towards PGY-4 residents and faculty, which also limits generalizability. Additionally, although we performed member checking, methods such as an external audit and triangulation would have been helpful to increase the rigor of the analysis.By omitting software-facilitated verbatim transcription of audio recordings there was the potential for diminished capture and preservation of data fidelity as well as a reduction in the standardization of the data as displayed to the coders. However, prior research has questioned the necessity for verbatim data transcription in qualitative research,Regardless, this study’s results were promising. Future research should include a more robust sampling of interns/residents from different institutions and/or specialties to support the conclusions reached from this study. Additional research should include investigating targeted interventions to address well-being prior to interns commencing their residency training. A mixed-methods study using both validated well-being assessment metrics  alongside qualitative analysis in a multicenter or multi-specialty prospective study would be a preferred methodology to assess the efficacy of any piloted interventions. Further research should also be directed to assess the effect and influence of the institutional culture on residents’ well-being.Despite variability in prior medical school and life experiences, incoming interns were underprepared in several domains of well-being, including emotional health, mindset and behavioral adaptability, and financial health. Targeted interventions toward these areas of well-being should be piloted and studied further for their potential to mitigate effects of burnout among resident physicians.