White adipose tissue (WAT) is involved in long-term energy storage and represents 10–15% of total body weight in healthy humans. WAT secretes many peptides (adipokines), hormones and steroids involved in its homeostatic role, especially in carbohydrate–lipid metabolism regulation. Recently, adipocyte-derived extracellular vesicles (AdEVs) have been highlighted as important actors of intercellular communication that participate in metabolic responses to control energy flux and immune response. In this review, we focus on the role of AdEVs in the cross-talks between the different cellular types composing WAT with regard to their contribution to WAT homeostasis and metabolic complications development. We also discuss the AdEV cargoes  which may explain AdEV’s biological effects and demonstrate that, in terms of proteins, AdEV has a very specific signature. Finally, we list and suggest potential therapeutic strategies to modulate AdEV release and composition in order to reduce their deleterious effects during the development of metabolic complications associated with obesity. White adipose tissue (WAT) distributes in discrete anatomical depots identified as subcutaneous adipose tissue (SAT) or visceral adipose tissue (VAT). The expansion of both depots contributes to obesity. Nonetheless, the development of metabolic complications is preferentially associated with VAT expansion . WAT repAt the cellular level, the storage of energy under the form of lipids, namely triacylglycerols, is ensured by adipocytes in a huge lipid droplet filling the cytoplasm. Fat cells are then highly expandable, with a size that can reach up to 150 µm in obese patients . The rapIn this context, adipocyte-derived extracellular vesicles (AdEVs) have recently been highlighted as important actors of intercellular communication that participate in metabolic responses to control energy flux and immune response. In this review, we will focus on the role of AdEV in the cross-talks between the different cellular types composing WAT with regard to their contribution to WAT homeostasis and metabolic complications development. We will also discuss the AdEV cargoes  that participate in AdEV’s biological effects on recipient cells. Finally, we will describe potential therapeutic strategies to modulate AdEV release and composition in order to reduce their deleterious effects during the development of metabolic complications associated with obesity.Extracellular vesicles (EVs) have long been viewed as conveyors of cellular waste used by the cell to get rid of harmful or unnecessary molecules . EVs desg pellet) from sEVs . Regardless of the EVs’ subclasses, numerous recent data point out that EVs convey biological messages and are critical actors of intercellular communication [Large EVs (lEV), whose sizes vary between 250 nm to 500 nm in diameter and are mainly referred to as microvesicles, are secreted following the budding of the plasma membrane. This process is dependent on calcium influx, which induces modification of the asymmetric phospholipid distribution of plasma membranes and phosphatidylserine outer leaflet exposure through specific regulation of enzyme activities  and favors the reorganization of cytoskeleton through calpain activation . First cnication , being iEV release has been recently identified as an essential part of the WAT secretome participating in autocrine, paracrine and endocrine communication . We haveStudying EV production during the course of 3T3-L1 differentiation reveals that proliferative adipocytes secrete more EV than quiescent mature adipocytes . Indeed,Active EV trafficking exists between different WAT cell types such as, for example, endothelial and adipocytes. For instance, endothelial EV-based transfer of caveolin into adipocytes has been demonstrated and shown to be sufficiently efficient to restore caveolin-1 protein levels in adipocytes depleted for caveolin-1 . EV-baseEvidence for the presence of AdEV in the blood is still scarce and difficult to evaluate in the absence of adipocyte-derived specific markers, but highly expressed adipocyte proteins such as aP2/FABP4, perilipin-1, adiponectin or PPAR have been identified in circulating EV . NonetheObesity, and particularly adipocyte hypertrophy, is an important contributor to type 2 diabetes (T2D), with insulin resistance being the main hallmark . DiffereBesides the role attributed to AdEV in WAT homeostasis, some studies have highlighted the endocrine effects of AdEV on distant cells from other tissues. EVs from brown adipose tissue (BAT) have been shown to regulate gene expression in the liver, although no evidence for specific organotropism was demonstrated . ProatheTaken together, these studies position adipose-derived EVs as a novel means of intercellular communication within WAT and likely between WAT and other distant organs. Of note, most of these studies have focused on the sEV and have neglected the lEV subpopulation. In addition, the risk of contamination of AdEV with lipoproteins contaminants and/or macromolecular protein complex is not considered or discussed. Further studies using standardized and robust EV isolation protocols are thus needed to delineate the molecular mechanisms underlying EV paracrine and endocrine effects.Different biological functions of AdEVs have been identified, and specific AdEV components  have been assigned to these effects.The formation of EVs implies that membranes can bud away from the cytoplasm during the formation of large EVs or during the formation of the intraluminal vesicles inside late endosomes to generate sEV/exosomes . During Therefore, when comparing 3T3-L1 adipocyte-derived EV proteomes, we highlighted specific protein subsets carried by lEV or sEV reflecting their respective mode of biogenesis . Large EIn human blood, different adipocyte-enriched proteins or adipokines are still detected in circulating EVs even after post-depletion of the major population of circulating plasma-derived EV  . These pCellular origin is also likely to influence EV protein content. To illustrate the relative contribution of EV origin with regard to their EV protein content, we performed functional enrichment analyses of two different EV sets of proteins, respectively derived from subcutaneous human primary adipocytes  and humap-value: 3.77 × 10−10) and positive regulation of cell motility . Conversely, differentiated 3T3-L1 adipocyte-sEV are enriched in proteins for RNA catabolic process , cell cycle phase , mitotic cell cycle phase , post-translational protein modification  and immune response-activating signal transduction .AdEV release is also closely linked with the adipocyte developmental stages since sEV production from 3T3-L1 cells was greater for the pre-adipocyte stage than for mature adipocytes . A plausAdEV production is also dependent on environmental signals, especially those associated with the development of obesity, as illustrated by an increase in AdEV release following lipid/glucose, hypoxic or inflammatory stimuli ,22,23,37Proteomic studies performed on AdEV from WAT explants of lean or obese/diabetic rodents (genetic obesity or high-fat induced) confirmed alterations of AdEV protein content within the course of obesity ,35,52,53Alternatively, a recent proteomic analysis was performed on human morbid obese visceral (VAT) and subcutaneous (SAT) WAT shed EVs from donors submitted to bariatric surgery . FunctioOf interest, AdEV proteins could be transferred into various recipient cells and are likely to participate in cancer development , inflammRNAs have been consistently found in EVs. Until now, the mechanisms favoring their export into EVs is unclear and unexplored in the case of AdEVs. Generally speaking, like for the majority of RNA-associated with EV, AdEV-RNA concentrations mirror cellular intracellular concentrations, suggesting a passive mechanism . NonetheOnly two studies have performed large-scale analyses of AdEV RNA content. Microarray profiling identified 7000 mRNA in 3T3-L1 adipocytes among the 9000 expressed in the cell . This hiAdEVs also contain small RNA species. Out of the 378 miRNAs expressed in bovine adipocytes, 48 were sorted into AdEVs  and 140 Although EVs are membrane-derived vesicles, one often-neglected component is their lipid content that EVs also transfer into recipient cells. EVs display specific lipid enrichment. Their membrane high protein/lipid ratio and the lipid asymetric distribution confer a high membrane rigidity in comparison with parent cells, which explains their stability in biofluids . InteresSeveral studies on cancer cells have shown that sEVs are strongly enriched in cholesterol, sphingomyelin (SM), glycosphingolipids and phosphatidylserine (PS)  and depleted in phosphatidylcholine (PC) (see review in ). IntereLipidomic analyses from AdEV are scarce, and the role of AdEV lipids in their biological functions in recipient cells needs urgently to be determined. During the development of obesity, important membrane remodeling occurs which is also illustrated by plasma membrane lipids reorganization. Of note, adipocyte plasma membrane lipids, such as cholesterol or sphingomyelin concentrations, are closely linked with the development of obesity-associated metabolic complications including insulin resistance ,72. TherIn the context of obesity, AdEVs released from adipocyte explants from high-fat-diet obese mice are strongly enriched in palmitic and stearic acids by comparison to AdEVs from standard diet mice, suggesting that the quality of the diet also has an impact on AdEV lipid composition . For insAs AdEVs appear as important metabolic mediators in obesity-associated pathologies, designing EV-based strategies to counteract deleterious AdEV effects, particularly in the pathophysiological context of obesity, might be envisaged. However, such approaches would imply specifically targetting AdEVs.In order to counteract AdEVs’ biological effects, one strategy to be envisaged might consist in modulating AdEV formation. Many drugs targeting either sEV formation or budding of the plasma membrane have been tested with promising results, mainly in the treatment of cancers . Very iBesides modulating EV proteins involved in MVB biogenesis and lEV budding, the regulation of specific intracellular lipid concentrations could be also envisaged for EV production. Indeed, an alternative ESCRT-independent pathway for EV biogenesis has been described involving the generation of ceramides. Ceramides are cone-shaped lipids that can both induce inward budding of MVB to generate ILVs and the release of sEV, and plasma membrane budding to generate lEVs , as theyIn addition to their involvement in EV release, lipids participate in the biological functions of EVs . TherefoIt has to be mentioned, however, that MVB trafficking and sEV/lEV release are parts of a complex intracellular trafficking and signaling networks, in close relationship with other cellular organelles to maintain cellular homeostasis and to release toxic components from the cells. Therefore, the full abortion of AdEV release cannot be envisaged as it would induce apoptosis. In addition, the question of targeting specifically adipose ceramide production in vivo fully remains speculative considering that adipocytes may not be the primary source of ceramides in WAT, which can rather be produced by other SVF cells.An alternative strategy to modulate AdEV lipid content is to modulate the intracellular lipid composition of the donor cells. Previous studies found a palmitate enrichment in AdEV, as well as other deleterious lipids, when AdEVs were isolated from mice fed with high-saturated-fat diets . A supplIt is well admitted that insulin-resistance associated with obesity increases the risk of cholesterol synthesis and release by the liver and its accumulation in WAT, leading to adipocyte hypertrophy. It was recently demonstrated that cholesterol from the diet can participate in this alteration . For insIndirect diet-effects to restore WAT function may also be envisaged and could possibly contribute to modulating AdEV content in a healthy manner. For instance, the gut microbiota is now recognized as a key component in the development of obesity and related metabolic complications. Evidence from animal studies and human clinical trials has suggested beneficial effects from prebiotic and various probiotic strains on physical, biochemical and metabolic parameters related to obesity . TherefoRecent data have provided proofs of concept that EVs from healthy/young subjects might be used in the management of metabolic complications associated with obesity such as insulin-resistance or in the management of aging-associated metabolic disorders. Indeed, injections of WAT macrophage-derived EVs isolated from lean mice improved glucose tolerance and insulin sensitivity in diet-induced obese mice . SimilarIn the context of cancer, it has been demonstrated that blood injections of antibodies against CD63 and/or CD9, two tetraspanins expressed at the surface of all EVs, could significantly reduce the development of metastasis without any effects on tumor growth in mice . As thesIn this review, we provide evidence that extracellular vesicles released from adipocytes (AdEVs) participate in the homeostasis of adipose tissue by exchanging lipids, proteins and RNA between the different cells that compose the fat tissue. AdEV composition is closely connected to the composition of the secretory cells, and the pathophysiological context of obesity impacts EV content. AdEVs thereby participate in the instigation of inflammation and insulin resistance of adipose tissue and are also involved in the spread of cancer cells. Nonetheless, numerous questions remain unanswered. They will need to be resolved in the future prior to envisaging therapeutic avenues to counteract the deleterious effect of AdEV during the development of obesity.


Heterosis is an expected consequence of whole-genome non-additive effects at the population level over evolutionary time. Understanding heterosis from the perspective of molecular genetic mechanisms alone may be elusive, because heterosis is likely an emergent property of populations. Hybrid breeding is a process of recurrent population improvement to maximize hybrid performance. Hybrid breeding is not maximization of heterosis per se, nor testing random combinations of individuals to find an exceptional hybrid, nor using heterosis in place of population improvement. Though there are methods to harness heterosis other than hybrid breeding, such as use of open-pollinated varieties or clonal propagation, they are not currently suitable for all crops or production environments. The use of genomic selection can decrease cycle time and costs in hybrid breeding, particularly by rapidly establishing heterotic pools, reducing testcrossing, and limiting the loss of genetic variance. Open questions in optimal use of genomic selection in hybrid crop breeding programs remain, such as how to choose founders of heterotic pools, the importance of dominance effects in genomic prediction, the necessary frequency of updating the training set with phenotypic information, and how to maintain genetic variance and prevent fixation of deleterious alleles.Although hybrid crop varieties are among the most popular agricultural innovations, the rationale for hybrid crop breeding is sometimes misunderstood. Hybrid breeding is slower and more resource-intensive than inbred breeding, but it allows systematic improvement of a population by recurrent selection and exploitation of heterosis simultaneously. Inbred parental lines can identically reproduce both themselves and their F Zea mays) to oil palm  heterosis emerges at the population level, even if it partially can be observed in single crosses, and (b) breeding involves populations rather than individuals alone . In a gr1 may differ from the mean of the average genetic values within each subpopulation, and this difference is termed panmictic-midparent heterosis  additive × additive epistasis, as new interactions among alleles are possible in the F1 compared to the parents. The portion of panmictic-midparent heterosis due to dominance, if present, can be thought of as recovery from inbreeding due to population structure, because subpopulations are by definition inbred relative to a population in which structure had never occurred. Although this base population in which structure never occurred is hypothetical and cannot be observed, it is possible to form an analogous population in Hardy–Weinberg equilibrium by randomly intermating the two subpopulations to form an F1, then randomly mating the F1 to form an F2. Heterosis in the F2, or F2 heterosis, is reduced by half compared to the panmictic-midparent heterosis in the F1  the randomly mating subpopulations can be randomly intermated, or (b) each subpopulation can first be selfed to produce fully inbred lines, and the fully inbred lines can be randomly intermated  can arise totally from epistatic effects without dominance, whereas inbreeding depression cannot . HeterosFrom the evolutionary perspective, heterosis in quantitative genetics ultimately rests on assumptions of biological dominance and biological epistasis, even though the additive model captures most of the effects of biological dominance and epistasis . For bioHeterosis can also result from overdominance, a type of biological dominance in which heterozygotes have more extreme phenotypes than both homozygotes, and alleles persist in populations at intermediate frequencies . One oveFinally, biological epistasis may contribute to heterosis as interactions of multiple loci contribute to fitness. Ample evidence of biological epistasis is available; for example, genes encoding transcription factor proteins may physically bind to DNA sequence motifs to activate or repress other genes which affect phenotype, among other mechanisms . HoweverSorghum bicolor). By the explanation of heterosis above, maize grain yield and sorghum biomass yield could be controlled by completely different genes and classes of genes, and dominant, overdominant, or epistatic action of the genes involved would lead to heterosis. If more individuals were sampled, which presented more combinations of genes and/or more genetic variants, then the genetic basis of observed heterosis could change.It is possible that heterosis can be explained fully by biologically additive, dominant, and epistatic gene action and that no single gene, class of genes, or physiological phenomenon causes heterosis . If so, It has been further hypothesized that actions of particular classes of genes or physiological effects of genes cause heterosis universally across traits and species . These pindica and japonica rice (Oryza sativa) show increased vigor, but reduced fertility, as do interspecific hybrids of donkeys (Equus asinus) and horses  and commercial heterosis, in which either the phenotypic value of the better-performing parent or a commercial check, respectively, is taken from the progeny phenotypic value, may be useful measures for varietal development but have no immediate relevance to genetic improvement of a population by selection, except perhaps to define selection targets . Better-Heterosis has also been restricted to describing only increases in progeny vigor relative to parents, i.e., positive heterosis . NegativFinally, heterosis has been conceptualized as a systems-wide phenomenon is which “the increased vigor, size, fruitfulness, speed of development, resistance to disease and to insect pests, or to climactic rigors of any kind” is observed . It is pAs parents, individuals transmit neither their phenotype nor their full genotype to their offspring. The allele, or more broadly, the gamete is the unit of inheritance. Only the additive portion of genetic value is heritable in the narrow sense if mating is random, because it does not depend on intra- or inter-locus combinations of loci which are potentially disrupted upon mating . If matiDespite its name, the concept of breeding value was not developed specifically for the purpose of breeding, but rather to explain the inheritance of quantitative traits: because Mendel discovered inheritance in traits which had discrete classes, it was initially unknown whether continuous, quantitative traits were also controlled by genes that could be transmitted from parent to progeny . Fisher True breeding value cannot be measured or even observed in the individual alone, since true measure of breeding value requires errorless observations of every possible progeny resulting from the individual mated to every possible member of the population to which it belongs. Therefore, breeding values are estimated. The estimation of breeding values was first accomplished by progeny testing. With random mating, the average performance of an individual’s progeny is an estimate of its breeding value ; Eq. 17.Well in advance of the sequencing technologies that would make markers cheaper, less biased, and more representative of the genome, the framework for genomic prediction of EBV using molecular markers was developed. Since 2001, tens of methods for genomic prediction of breeding values, as well as the genetic values of lines used for production rather than breeding, have been developed . These mIn hybrid breeding, genomic prediction can be used to (a) predict the combining abilities of inbred lines, and (b) predict the performance of new hybrid genotypes . To predPrediction accuracy is an important determinant of whether genomic prediction will lead to effective selection across environments, years, and genotypes. Factors which influence accuracy of GEBVs include choice of statistical model, trait heritability, precision in geno- and phenotyping, size the of the training set, and relatedness/common LD structure of the training and testing set . ModelinThough modeling non-additive effects would be expected, then, to improve prediction accuracies, a reminder is warranted: modeling non-additive genetic effects will only improve prediction accuracies if non-additive genetic effects exist for the traits of interest and non-additive genetic effects can be estimated accurately in the populations of interest . In lighper se performance and specific male and female morphotypes for hybrid seed production  has been studied by simulation in oil palm . Cros et parents . In a fo parents .1 hybrids’ mean genetic value would differ from the parents’ mean genetic value. To use both parent and hybrid geno- and phenotypes in the same training model when directional dominance is present, it would likely be necessary to include a fixed effect for the average heterozygosity of each individuals’ genotype following A key consideration in both studies was that dominance was not simulated even though RRGS was used, so the mean genetic values of the hybrids were equal to the mean of their parents , 2018. FReciprocal recurrent selection differs slightly from recurrent selection within populations in that breeding values depend on allele frequencies in both heterotic pools . Two issAs heterotic pools are developed, the next module is initiated: parents of crosses for production pipelines are selected. First, individuals are selected from each heterotic pool . In estaper se performance, often for traits such as disease resistance  production or selfing. During inbreeding of lines from two-parent crosses or upon availability of DH lines, lines are selected for sistance . Then, tsistance . Only thsistance . Parentasistance .1 hybrid seed by cross-pollination is too expensive on a large scale with many hybrid combinations (as in self-pollinated crops), then F1:2 individuals can be substituted into the training set with only modest reductions in prediction accuracies  is equal to the number of parents (two), so heterosis is maximized in single crosses.Clonal propagation methods also reproduce non-inbred genotypes. Many non-inbred economically important crops, including sugarcane, potato, and cassava, are propagated asexually as clones rather than from seed . The draIf a uniform population is not necessary, then breeding open-pollinated varieties (OPVs) can lead to effective utilization of heterosis. For much of human history, OPVs were the only varieties available. This is still true in regions which the commercial breeding sector does not yet serve, and OPVs can outperform hybrids in some low-input environments . In UnitIf heterosis is largely due to dominance rather than overdominance, then inbred lines which perform as well as hybrids must be possible, although they may take time to develop due to linkage disequilibrium . There iAll plant breeding programs require genetic variance for continued progress. Within any breeding population, reducing effective population size by selection early in the program may limit long-term genetic gain . Though (a)Optimum contribution selection: genetic value is maximized while inbreeding is constrained to give the optimal contributions of parents to the next generation, i.e., number of progeny .(b)Weighting of rare alleles: allelic effects are weighted by their frequency such that rare favorable alleles are preserved .(c)Weighted genomic selection: allelic effects are weighted by their frequency, but also the magnitude of their effect, such that rare favorable alleles which tend to have large effects on EBV are preserved .(d)Genotype building: a subpopulation is selected algorithmically to segregate for maximal haplotype values, then intermated such that the two best segments ultimately segregate with equal frequency .(e)Optimal cross selection: selection intensity, inbreeding, and cross allocation are simultaneously optimized .(f)Usefulness criterion parental contribution: overall and within-family selection intensity, inbreeding, and cross allocation are simultaneously optimized .(g)Genomic mating: genetic value, inbreeding, and risk  are simultaneously optimized .(h)Optimal haploid value selection: outbred individuals are selected for the predicted value of the best DH lines they could produce, then used to make DH lines for which breeding or genetic values are then predicted .(i)Optimal population value selection: sets of individuals are selected for their collective rather than individual maximum possible haploid value .(j)Expected maximum haploid breeding value selection: individuals are selected for their maximum possible haploid value .(k)IND-HE: genetic gain and expected heterozygosity are balanced in selection .(l)Look-ahead selection: sets of individuals are selected for their collective rather than individual maximum possible haploid value, with the maximum value occurring in a user-specified target generation .(m)Optimal contribution selection to update the reference population: assuming a breeding population is used to update the training set for prediction, selecting the training set candidates by optimal contribution selection balances genetic gain and inbreeding .(n)Optimal contribution selection with branching: the population mating scheme is branched into two paths which maintain genetic diversity and maximize genetic gain .A simulation comparing all methods of long-term selection optimization in hybrid breeding programs is not yet available . DevelopFor hybrid programs specifically, selection optimization methods to prevent unintentional allelic fixation during RRGS in opposite heterotic groups could be useful . Anotherper se and testcross performance with European testers have also demonstrated a 15% yield gap between mean testcross yield and mean commercial yield (Though advanced commercial maize hybrid breeding programs should not be construed as resulting from long-term genomic selection, the genetic base of North American and European commercial maize is narrow, prompting concern that limiting loss of diversity has occurred . Some apal yield . Genomical yield . Additioal yield .The limits of long-term selection within closed breeding populations are unknown . BreedinExact recommendations for crop hybrid breeding programs are situation-dependent, including whether and how to apply genomic selection. Factors to consider in implementation of genomic selection strategies include budget, trait heritability, cost and accuracy of phenotyping, length of the breeding cycle, and infrastructure for genomic selection (e.g., marker availability, marker cost, bioinformatics software, statistical expertise, etc.; Mating system is a major factor driving the use of hybrid breeding systems . Most hyFor a breeding program, the question then remains whether the gains of heterosis are outweighed by the costs of breeding hybrids in autogamous crops. The costs of breeding hybrids can be reduced by developing male-female heterotic pools, scalable male sterility systems, and hybridization systems. The gains of heterosis can be increased by breeding heterotic pools. Thus, initial investment to establish a hybrid breeding program may be high, but it could provide higher returns over time than an inbred program. A case study of hybrid wheat, for example, found that although hybrids are currently competitive with inbred varieties, whether long-term improvement of hybrids keeps pace with lines strongly depends on budget, cost of hybrid seed production, and GCA variance . Use of Whether for autogamous or allogamous species, genomic selection methods have potential to increase rates of genetic gain at every stage of hybrid breeding. Use of genomic selection, for example, to rapidly develop heterotic pools in crops in which they are not well-established—e.g., rice and wheat— is worth trying . FurtherThe era of genomic selection offers new opportunities in hybrid breeding. Genomic selection methods can jumpstart the establishment of heterotic pools by founder selection and use of RRGS to unlock heterosis in new hybrid breeding programs. Genomic selection can also shorten the notoriously long hybrid breeding cycle by reducing the need for testcrosses and their phenotypic evaluation. Though implementing genomic selection methods requires optimization to specific hybrid breeding situations, a sufficient framework for breeders to make genomics-assisted decisions already exists.ML conducted the literature review and wrote the manuscript. AS and JR conceived of the review topic, edited the manuscript, and generated cross-disciplinary insights through discussion. All authors contributed to the article and approved the submitted version.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.


Metronidazole-induced encephalopathy (MIE) is a rare and often under-recognized iatrogenic condition. The diagnosis should be considered in metronidazole-treated patients presenting with acute encephalopathy, unprovoked seizures and cerebellar signs. While typical magnetic resonance imaging (MRI) findings strongly support the diagnosis, electroencephalography (EEG) features have been rarely reported and poorly described. We present a longitudinal EEG assessment in one patient with encephalopathy due to metronidazole toxicity who presented a peculiar EEG pattern presentation and evolution. During the acute phase of encephalopathy, the EEG showed a monomorphic, sharply contoured theta activity symmetrically represented over frontal regions with an anterior–posterior progression which evolved in parallel with clinical worsening. Together with a systematic review of the literature, we discuss whether this EEG activity may represent a distinct neurophysiological correlate of ‘cerebellar encephalopathy’. Metronidazole is an antimicrobial agent commonly used in the treatment of several protozoal and anaerobic infections. It is usually well tolerated, but it has occasionally been associated with the development of serious neurological adverse events, including peripheral neuropathy, cerebellar dysfunction, visual impairment, vestibulotoxicity, cochleotoxicity, ataxic gait, dysarthria, seizures and encephalopathy  . The incA 64-year-old Caucasian man came to our attention because of bilateral tonic-clonic seizures followed by altered mental status. He was hospitalized for three months because of an intra-abdominal abscess which he developed after jejunal perforation related to endoscopic retrograde cholangiopancreatography (ERCP). No history of alcohol intake or substance abuse was reported. He had been receiving metronidazole 500 mg four times per day for about 10 weeks (cumulative dose: 126 g). On examination, he was alert but confused and unable to perform either complex or simple motor tasks. Spontaneous speech was minimal, and no ocular abnormalities were noted except for bilateral nystagmus on extreme gaze. Slight dysmetria in his upper limbs was observed and he referred numbness in hands and feet. During hospitalization, he also experienced some episodes of psycho-motor agitation and, on other occasions, transitory alteration of consciousness with unresponsiveness that raised the suspicion of focal seizures with impaired awareness. An EEG was performed, showing frequent and very brief (<10s) runs of waxing and waning, bilateral and symmetric medium voltage monomorphic sharp theta activity over fronto-central regions A.Levetiracetam 250 mg twice a day was started. A few days later, he presented a new episode of impaired awareness followed by focal-to-bilateral tonic-clonic seizure, therefore levetiracetam was increased up to 500 mg twice a day. After the occurrence of a new cluster of rapidly occurring bilateral tonic-clonic seizures, the patient received lorazepam 4 mg i.v. and levetiracetam 1000 mg i.v. A brain MRI showed enhanced FLAIR signal bilaterally in the dentate nuclei of the cerebellum and in the midbrain tectum, with diffusion restriction and without contrast enhancement A,B.Three days later, his mental status was still partially altered. EEG performed 5 and 6 days after the first tonic-clonic seizure confirmed the persistence of rhythmic monomorphic sharp theta activity, organized in more prolonged sequences symmetrically involving fronto-centro-temporal regions B,C. AdmiA systematic review was performed applying the PRISMA  guidelines . Full-teArticles were included if they met the following inclusion criteria: (i) described patients with neurological signs or symptoms attributed to metronidazole toxicity ; (ii) included a description or a picture of at least one EEG recording; (iii) written in English language; and (iv) published in a peer-reviewed journal.The exclusion criteria were: (i) the study reported patients with more than one apparent cause of encephalopathy; (ii) studies conducted in animals or in vitro models; and (iii) conference proceedings, reviews and books.Data extraction was executed on 288 articles .Fourty-six articles were excluded because of duplicates. Data were extracted on the basis of the following checklist: authors, year and type of publication ; characteristics of the participants involved in the study and aim of the study; and presence of EEG description (yes or no).After an accurate revision of full manuscripts, nine articles satisfied the inclusion/exclusion criteria .We identified nine cases of MIE with an EEG description; however, EEG recordings were only available in three cases for critical revision. Most cases presented normal or unspecific EEG findings and the majority of seizures, if present, were reversible after the discontinuation of metronidazole. In one case only, NCSE was the clinical manifestation of metronidazole toxicity . In two Finally, our systematic review suggests that the EEG findings in MIE do not seem to correlate with clinical outcome, with the presence of seizures, with the severity of encephalopathy, nor with the cumulative dose of metronidazole therapy.MIE is an uncommon complication of metronidazole therapy. It typically manifests with dysarthria and gait instability, but altered mental status, convulsive seizures and permanent sequelae have been reported . Risk faBilateral tonic-clonic seizures are an uncommon manifestation of MIE and the EEG findings associated with this condition are considered unspecific . In geneWe observed a very characteristic EEG pattern in our patient , displayThe systematic review of the literature did not highlight a specific EEG pattern for MIE, neither did it confirm our own findings, although in one case, the focal slowing was mainly anterior . HoweverThe possible pathogenic mechanisms and the neurophysiological explanations for the anterior predominance and diffusion of the EEG slow abnormalities in MIE could be diverse.The influence of cerebellum, which is one of the main targets of metronidazole toxicity , on fronThese anatomo-clinical correlations support our own findings showing a frontal EEG prevalence of the toxic insult during the early phase of MIE. Moreover, sLORETA solution performed on our patient’s EEG see  providesIn our patient, the acute encephalopathy was evident in the EEG through a rhythmic oscillatory activity in the theta frequency range. Neural oscillations underlie brain function and are essential to ensure complex and integrative tasks for both cerebral and cerebellar cortex . PreviouThe increase in theta activity is usually caused by an alteration of the underlying brain tissue or its network , and speIn turn, the frontal disconnection from the cerebellum may cause an increase in cortical excitability and thus explain an increased risk of seizures . In factIn conclusion, we provide a prospective longitudinal EEG study of one patient with MIE showing a peculiar EEG pattern evolution. The systematic review of the literature does not support an EEG peculiarity in these patients, because of a substantial lack of accurate reports and longitudinal assessments. However, our data suggest a possible specific EEG pattern (sharp theta activity with a progressive antero-posterior diffusion), which could fit with the radiological and clinical evidence of cerebellar dysfunction caused by MIE.Clinicians should be aware of this possible EEG manifestation of MIE since it may eventually suggest the diagnosis of this rare condition, which requires the prompt withdrawal of metronidazole therapy in order to prevent severe and permanent neurological sequelae.


Despite great strides being achieved in improving cancer patients’ outcomes through better therapies and combinatorial treatment, several hurdles still remain due to therapy resistance, cancer recurrence and metastasis. Drug resistance culminating in relapse continues to be associated with fatal disease. The cancer stem cell theory posits that tumors are driven by specialized cancer cells called cancer stem cells (CSCs). CSCs are a subpopulation of cancer cells known to be resistant to therapy and cause metastasis. Whilst the debate on whether CSCs are the origins of the primary tumor rages on, CSCs have been further characterized in many cancers with data illustrating that CSCs display great abilities to self-renew, resist therapies due to enhanced epithelial to mesenchymal (EMT) properties, enhanced expression of ATP-binding cassette (ABC) membrane transporters, activation of several survival signaling pathways and increased immune evasion as well as DNA repair mechanisms. CSCs also display great heterogeneity with the consequential lack of specific CSC markers presenting a great challenge to their targeting. In this updated review we revisit CSCs within the tumor microenvironment (TME) and present novel treatment strategies targeting CSCs. These promising strategies include targeting CSCs-specific properties using small molecule inhibitors, immunotherapy, microRNA mediated inhibitors, epigenetic methods as well as targeting CSC niche-microenvironmental factors and differentiation. Lastly, we present recent clinical trials undertaken to try to turn the tide against cancer by targeting CSC-associated drug resistance and metastasis. Cancer remains one of the major causes of mortality globally, with many recent studies showing significant increases in its incidence ,2. RecenCSCs have been defined as a subset of cancer cells with the ability to self-renew and to differentiate into non-CSC cancer cells within the tumor mass ,8. The CFrom the early days of their discovery, many studies have shown that CSCs are undifferentiated tumor cells able to generate tumors ,21,22. TDue to their ability to resist therapy, CSCs can travel to distant sites and form new tumors. Whilst the process of metastasis appears disorganized, metastatic lesions are the main cause of cancer deaths and therapy resistance . SignaliThis review is an updated critical analysis and distillation of available information on CSCs and their involvement in cancer therapy resistance and metastasis. By targeting inherent CSCs properties that allow CSCs to be tumorigenic, resistant and also metastatic, new drugs being developed offer a better promise at curing cancer.Current therapies are unable to eliminate cancer partly due to CSCs’ enhanced ability to withstand treatment regimens ,30. CSCsSeveral studies demonstrated an increase in CSCs in tumors after cancer treatment, clearly illustrating their persistence during treatment ,76,77. CCSCs ability to resist therapy is widespread and referred to as multidrug resistance. This capability stems from the ability of CSCs to express increased detoxifying enzymes, increased activation of survival signaling pathways, DNA repair mechanisms as well as drug efflux pumps ,78. In aThe ALDH superfamily is a large family of proteins and several members including aldehyde dehydrogenase 1 (ALDH1) have been implicated in drug detoxifying activities ,82. In iIn addition, CSCs demonstrate increased expression of drug effluxing proteins such as the ABC transporters  99,100,,100,101.Several other proteins associated with apoptosis are also involved in the survival of cancer cells and CSCs ,114. For6-methylguanine DNA methyltransferase (MGMT) expression and activity in glioma stem-like cells were responsible for temozolomide resistance -S-phenylglycine t-butyl ester), targeted CSCs in head and neck cancer [Another important signaling cascade targeted in CSCs is the Notch pathway. Xu and colleagues demonstrated that inhibition of Notch signaling via the use of RO4929097 combined with chemotherapy has a beneficial effect in glioma patients with an observed reduction in CSCs . Zhao ank cancer . Anotherk cancer . Hedgehok cancer . Miyazakk cancer . Clinicak cancer ,306.Furthermore, the inhibition of the STAT3 pathway through the use of napabucasin was shown to reduce the viability of hematopoietic CSCs as well as their tumorigenic capabilities . NapabucGiven the dependence of tumor formation and growth on the formation of blood vessels within the TME, inhibition of angiogenesis has been touted as having clinical value and could improve cancer patients’ outcomes . One of The key to the formation of new blood vessels is the creation of space for cells to burrow through. Thus, matrix metalloproteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), play important roles in enabling the formation of new blood vessels ,334,335.Whilst research on the development of new drugs is an ongoing endeavor, new strategies being developed to eradicate cancer include targeting the stromal cells, CSCs and immune cells within the TME ,30. ImpoSeveral antibodies have been developed to induce an anticancer immune response. For example, Ipilimumab is an anti-CTLA-4 inhibitor that was developed and used in patients with advanced melanoma . PatientResistance to immune checkpoint therapy has been suggested to be caused by CSCs. Stemness as well as increased angiogenesis has been associated with reduced recognition of T cells ,386,387.One of the best immunotherapies under trial and available for cancer patients is the chimeric antigen receptor (CAR) T cell transfer. CAR T cell transfer can be used for both solid and liquid malignancies ,397. CARThe above-described strategies require moderation as the overstimulation of the immune system can be detrimental. Done properly with proper control, immunotherapy can become a very good and natural way to respond to the presence of cancer cells in the body. Challenges remain in terms of immunotherapy for cancer treatment. For example, Noh and colleagues demonstrated that CTL-mediated immune selection drives tumor cell evolution toward the CSC phenotype, with the resulting CSCs demonstrating great heterogeneity .Recent data point to possible manipulation of epigenetic states or mechanisms in cancer cells by altering molecular factors that are involved. Major hurdles remain including the identification of compounds and agents able to selectively target epigenetic mechanisms in cancer cells at low concentrations. HDAC inhibitors for example are mostly considered as pan-inhibitors and display many side effects. Many pan-HDAC inhibitors have been approved by the FDA or are under trials. One well studied HDAC inhibitor is Vorinostat, which targets HDAC-1-3 and HDAC 6. Several clinical trials using Vorinostat as a standalone drug or in combination with others are underway for cancers that relapsed or other solid tumors ,403,404.The BET family, which are chromatin readers, interact with chromatin modifiers as well as enzymes to affect chromatin modification. Proteins containing bromodomains dock on acetylated histones ,408. ConGreat improvements and success in cancer treatments has been recorded in the past few years mainly due to prevention campaigns, early diagnosis and better therapies. Overall, better and improved cancer patient outcomes have been observed. Even with these observations, millions of cancer patients die each year. One major hurdle to improved cancer patient outcomes is the development of resistance to therapies and disease relapse . Importa


Approaches to the identification of metabolites have progressed from early biochemical pathway evaluation to modern high-dimensional metabolomics, a powerful tool to identify and characterize biomarkers of health and disease. In addition to its relevance to classic metabolic diseases, metabolomics has been key to the emergence of immunometabolism, an important area of study, as leukocytes generate and are impacted by key metabolites important to innate and adaptive immunity. Herein, we discuss the metabolomic signatures and pathways perturbed by the activation of the human immune system during infection and vaccination. For example, infection induces changes in lipid  and amino acid pathways , while vaccination can trigger changes in carbohydrate and bile acid pathways. Amino acid, carbohydrate, lipid, and nucleotide metabolism is relevant to immunity and is perturbed by both infections and vaccinations. Metabolomics holds substantial promise to provide fresh insight into the molecular mechanisms underlying the host immune response. Its integration with other systems biology platforms will enhance studies of human health and disease. Metabolites are small molecules  produced by regulatory mechanisms and during cellular processes or acquired from exogenous sources, including diet and xenobiotics such as drugs . MetabolAs early as 1955, biochemical research provided the first perspective of a comprehensive cellular metabolome comprised of ~20 metabolic pathways . As massWithin the framework of precision medicine and in comparison to other systems biology approaches such as transcriptomics  and proteomics, metabolomics provides a nearly instantaneous snapshot of metabolism. The metabolome rapidly responds to even minor stimulations, rendering metabolomics a powerful approach to assess quantitative responses to stress , nutritiThis review highlights metabolomics as an emerging tool for identifying signatures and pathways in the host response to infection and vaccination.Systems biology approaches that focus on a single class of molecules, such as transcripts (transcriptomics) or proteins (proteomics), can provide important but limited understanding of the biological mechanisms of disease . Their cRecent systems immunology methodologies have enabled a comprehensive analysis of multiple immune system features in parallel, as well as the identification of cellular and molecular biomarkers not previously known to be relevant to immune responses . Multi-oThe potential contribution of metabolomics in the context of infectious diseases and host–pathogen interactions appears particularly promising. Host–pathogen interactions impact leukocyte immunometabolism, thereby shaping their response to infection. Plasm- or serum metabolomics can profile the metabolome in an infected patient, reflecting the systemic responses of diverse cell types in various organ systems affected by a specific pathogen and thereby identifying potential biomarkers of infection . Finally+ T cells, favoring their differentiation into Th17 rather than Treg cells, and the production of pro-inflammatory cytokines in response to T cell receptor activation [The interplay between metabolism and the immune response is increasingly recognized, and distinct metabolic needs and demands define responses to infection and vaccination . Immunomtivation .In contrast, adenosine monophosphate-activated protein kinase (AMPK), an energy sensor kinase, serves as an immunometabolic checkpoint in T cell development and effector responses as well as in memory T cell differentiation by regulating the metabolic switch from aerobic glycolysis to oxidative phosphorylation of lipids . As is tDuring infection, several metabolic changes occur, with reciprocal effects between the pathogen and the host. Metabolic adaptations occurring in eukaryotic hosts upon acute infection by bacterial or viral pathogens are complex, as the pathogen competes for host nutrients and other metabolites to satisfy its bioenergetic and biosynthetic requirements. In contrast, the host response is aimed at the elimination of the invading pathogen . Most miCommon metabolic reactions are essential to host cell defense  to preveMycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is an example of the metabolic adaptation of a bacterium to the host environment, as this pathogen has learned to survive in the host causing a latent infection (LTB) which can progress to active TB disease in ~10% of latently infected individuals. Carbon metabolism is a major determinant of the pathogenicity of Mtb, as demonstrated in animal models, where the lack of carbon sources causes failed replication and survival. It is essential to fuel Mtb growth [13C-labeled carbon substrates revealed that Mtb could simultaneously catabolize multiple carbon sources  to augment its growth [+ T cell responses, inducing immune tolerance and bacterial persistence, and could also protect the host from excessive inflammation. Metabolomics can identify immunometabolic pathways associated with TB progression, discriminating active TB from latent TB [b growth . Untarges growth . The sphs growth . Sphingos growth . Increasatent TB . Fatty aatent TB ,73. Of natent TB . Lastly,atent TB .Viruses depend on the host cell to obtain macromolecules and on host biosynthesis machinery to replicate; they utilize host cell metabolism according to their specific needs . Viral r+ T cells [+ T cells most often are effectors of the acute lytic infection, which may explain the differences. HIV metabonomic studies utilizing biofluids from HIV-infected patients and controls have been used to identify HIV infection biosignatures, disease progression, and immunological responses to treatment [Retroviruses directly alter host cell metabolism as well. Metabolites involved in glycolysis were increased in human immunodeficiency virus (HIV)-infected CD4 T cells  but decr T cells . Macrophreatment . Plasma reatment . Of notereatment , suggestInterestingly, the interaction between glucose metabolism and the inflammatory cytokine network might trigger the host’s systemic inflammatory response. Metabolomics of peripheral blood mononuclear cells (PBMCs) challenged with IAV or H1N1 demonstrated that an increase in glucose metabolism promotes viral replication and cytokine production . Plasma In the context of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, advances in metabolomics can shed light on the pathogenesis of coronavirus disease 2019 (COVID-19) that could inform the development of novel therapeutics. Patients with COVID-19 exhibit changes in serum tryptophan metabolism and increased circulating levels of glucose and free fatty acids (FFA), consistent with altered carbon homeostasis, compared with SARS-CoV-2-negative controls. Interestingly, these findings correlate with the detection of clinical laboratory markers of inflammation (interleukin-6 (IL-6) and C-reactive protein) and renal function  . Plasma Systems vaccinology provides fresh insights into distinct age- and sex-specific vaccine-induced responses ,108,109.Systems vaccinology studies have uncovered metabolic pathways that correlate with vaccine immunogenicity and may have critical roles in immune response mechanisms ,110,111 A plasma metabolomic analysis of immune responses to herpes zoster (shingles) Zostavax vaccine demonstrated a strong association of transcriptomic pathways with multiple metabolic pathways, including lipid  and AA pathways (methionine and cysteine) at Day 3 postvaccination . These mIn a phase III multicenter clinical trial, the Hantavax vaccination (Hantavirus vaccine) demonstrated dose-dependent upregulation of folate biosynthesis, nicotinate, nicotinamide, and arachidonic acid metabolism, thiamine levels, and pyrimidine metabolism in the high responder vaccine group . In lighMetabolomics is also being applied to study vaccine safety. A human plasma metabolomics study of 200 individuals pre- and post-small pox immunization discovered novel biomarkers for an adverse event following immunization (AEFI), including redness at the local site of vaccination or a severe allergic reaction . IndividCommon metabolic pathways induced by infection and vaccination include AA , carbohydrate (tricarboxylic acid (TCA) cycle, glycolysis, glucose, propanoate), nucleotide (purine), and lipid metabolism (bile acids). Remarkably, these are metabolic pathways known to shape the immune cell response ,122. Numerous reviews indicated that AA metabolism shapes the host’s physiology, growth, reproduction, and immunity. AA metabolites also serve as the energy source for cells and as regulators for cell signaling and host metabolism ,124. AA Immunometabolism involving carbohydrate pathways proposes that innate or adaptive naïve immune cells mainly rely on shifting oxidative phosphorylation to glycolysis (Warburg metabolism) upon immune activation . CarbohyPurine metabolites provide the necessary energy and cofactors to promote cell survival and proliferation . AdenosiThe application of metabolomics for precision medicine is dependent on our ability to categorize infectious disease states or vaccine immunogenicity based on reproducible metabolic signatures that reflect specific, discernible phenotypes and can be used as a consistent readout . For allPotential obstacles to the broader application of metabolomics for precision medicine have been the prohibitive cost of clinical metabolite profiling and the time-consuming nature of extraction and derivatization of certain metabolites. The typical cost of metabolomics at this time is hundreds of dollars per sample, such that the broad application of global metabolomics is unaffordable, limiting metabolomics-based applications to well-funded clinical trials and perhaps the most privileged patients. To overcome this limitation, technologies such as NMR, which is more affordable than mass spectrometry , could bAt present, the US Food and Drug Administration (FDA) regulations allow the application of metabolomics as a diagnostic tool for in vivo newborn screening of metabolic diseases  and for As the metabolomics research community finds ways to overcome the current limitations of this powerful technology, the way for personalized metabolic phenotyping will be paved ,148, whiwww.immport.org), will enable the discovery and validation of cellular and molecular signatures of infection and immunization. Eventually, when integrated with clinical information and validated in clinical contexts, such knowledge may help leveraging metabolic signatures to enhance the diagnosis and treatment of infectious diseases and inform vaccine discovery and development. Given the power of metabolomics and the growing evidence that metabolic pathways are relevant to immune responses, we predict that collaborative data verification and integration efforts will eventually enable the use of metabolic signatures to inform clinical decision-making. Finally, robust structures and incentives for data sharing will be critical to the metabolomics field’s success. Extensive studies by investigators in the areas of infectious diseases, vaccinology, and metabolomics, coupled with data sharing, such as that fostered by the Human Immunology Project Consortium ImmPort database ,153 (wwwAs the field of metabolomics evolves in accessibility, usability, and sophistication, metabolomic data will increasingly be integrated with clinical and other systems biology data to gain deep insights into the biology of health and disease. On addition to presenting metabolic pathways triggered by infections and vaccinations, our review also highlights metabolomics as a useful tool for discovering and identifying biomarkers of disease subtype and stage and treatment response. These biomarkers can be used to distinguish patients infected with different pathogens, predict vaccine-induced protection against these infections, and provide insight into human immunity. Given the emerging evidence that metabolism plays key roles in infection and vaccine responses, a growing number of metabolites will likely emerge as targets for developing biomarkers, predictive algorithms, therapeutic targets, and preventative modalities.


Ischemic stroke, which is caused by a sudden clot in the blood vessels, may cause severe brain tissue damage and has become a leading cause of death globally. Currently, thrombolysis is the gold standard primary treatment of ischemic stroke in clinics. However, the short therapeutic window of opportunity limits thrombolysis utility. Secondary cerebral damage caused by stroke is also an urgent problem. In this review, we discuss the present methods of treating ischemic stroke in clinics and their limitations. Various new drug delivery strategies targeting ischemic stroke lesions have also been summarized, including pharmaceutical methods, diagnostic approaches and other routes. These strategies could change the pharmacokinetic behavior, improve targeted delivery or minimize side effects. A better understanding of the novel approaches utilized to facilitate drug delivery in ischemic stroke would improve outcomes. The NBDDS can meet the requirements of an ideal drug delivery system. The prodrug strategy is another commonly used pharmaceutical approach for targeting the brain: prodrugs provide improved stability, selective release, and targeted-delivery. Recently, burgeoning strategies such as cell membrane-encapsulated nanoparticles and exosomes have been employed in ischemic stroke treatment due to their biological targeting properties.Nanotechnology has been an extensively studied and utilized drug delivery system in the past few decades, including drug delivery in nerve disease Silva, . Being n4.1.1.Among the variety of drug delivery systems above, the liposome is the most studied one. Liposomes are spherical vesicles prepared by mixing phospholipids and cholesterol in different proportions. The double-layer structure enables them to be loaded with either hydrophilic or hydrophobic drugs and the cell-like membrane structure endows them with low toxicity, good biocompatibility, and prolonged circulation time. In addition, liposomes surfaces are easily modified to achieve targeted-delivery and controlled release. Most importantly, the lipophilicity allows them to enter the brain through the BBB using endocytosis, which has shown to be a promising drug delivery system in treating stroke and nanostructured lipid carriers (NLCs) also help transport drugs into the brain. Lipid nano-formulations are composed of fatty ingredients including fatty acids, long-chain or medium-chain triglycerides, and other lipid materials. Lipophilic drugs are loaded into the lipid nanoparticles, and many possess a high oral bioavailability and long retention time  and Ce(4+) oxidation states. Consequently, Ceria and edaravone work together to remove the reactive oxygen species (ROS) caused by the thrombus and protect nerves. In vitro transwell assays confirmed the essential BBB crossing effect of the ANG ligand. ANG-LRP-mediated transcytosis enabled the high accumulation of the ceria and edaravone  and chitosan are the most widely studied materials and have proven to be effective drug delivery systems  is an effective approach to brain drug delivery. This unique delivery route bypasses hepatic metabolism and does not enter the systemic circulation. Without the obstacle of the BBB, the delivery efficiency is also enhanced compared with the intravenous route  is essential for a good prognosis. Therefore, it will be a wise choice to design a dual-sensitive drug delivery system that responds to both inflammation and oxidative environment for ischemic stroke in the future. With the extensive study of drug delivery systems and the further exploration of the ischemic stroke mechanism, the novel drug delivery strategies will hold great potential in delivering therapeutics against ischemic stroke.


New discoveries based on genetic and epigenetic evidence have significantly expanded the understanding of diffuse gliomas. Molecular biomarkers detected in diffuse gliomas are not only potential targets for radiotherapy, chemotherapy, and immunotherapy, but are also able to guide surgical treatment. Previous studies have suggested that the optimal extent of resection of diffuse gliomas varies according to the expression of specific molecular biomarkers. However, the specific guiding role of these biomarkers in the resection of diffuse gliomas has not been systemically analyzed. This review summarizes several critical molecular biomarkers of tumorigenesis and progression in diffuse gliomas and discusses different strategies of tumor resection in the context of varying genetic expression. With ongoing study and advances in technology, molecular biomarkers will play a more important role in glioma resection and maximize the survival benefit from surgery for diffuse gliomas. Histologically, diffuse gliomas originate from aberrant neural progenitor stem cells of the central nervous system and composed of either astrocytes or oligodendrocytes. Although the morphology-based classification system from the World Health Organization (WHO) in 2007 is highly significant for the characterization of diffuse gliomas, it is unable to explain the evident differences in prognosis of patients with the same histopathology , 2. MoleThe goal of traditional treatment strategies for diffuse gliomas was to achieve maximum resection in the context of protecting neurological and functional integrity, and further adjuvant radiotherapy and/or chemotherapy is applied according to the extent of resection (EOR) and histopathology . The degMultiple retrospective studies and large meta-analyses have demonstrated that, regardless of low- or high-grade, primary or recurrent, greater EOR can significantly prolong both progression-free survival (PFS) and overall survival (OS) of diffuse gliomas compared with partial resection or biopsy –9. HowevIsocitrate dehydrogenase (IDH) is an enzyme participating in the tricarboxylic acid cycle. IDH 1 and IDH 2 are two subtypes of IDH and responsible for converting isocitrate to alpha-ketoglutarate in the cytoplasm and mitochondria, thereby influencing the metabolic process. Studies have confirmed that, although IDH mutation occurs in the early stages of glioma formation and may affect DNA demethylation and lead to tumorigenesis, the exact mechanism remains unclear . IDH mutIn patients with diffuse astrocytoma, the effect of surgical resection on prognosis is different according to IDH expression and pathological grade. A previous study involving 228 adults with supra-tentorial low-grade gliomas (WHO grade 2) found that postoperative tumor volume exerted a negative effect on OS. The impact was more evident in astrocytoma with IDH mutations, in which any tumor residual will significantly reduce OS. Therefore, maximal resection in the primary operation is crucial, and a “second-look” operation may be necessary to ensure total resection for IDH-mutant tumors, if it can be performed safely . Other sRegarding anaplastic diffuse astrocytoma, a study analyzed the relationship between EOR and prognosis and revealed that GTR can significantly prolong OS of patients with IDH-mutant anaplastic diffuse astrocytoma but not wild-type . SimilarOn reviewing the existing literature, we conclude that radical surgical treatment is beneficial for patients with diffuse astrocytoma. Even if the tumor is located in a functional area, it is worthwhile to realize total resection at the cost of few partially unessential function because of the brain plasticity. Relatively conservative surgical treatment is recommended only for patients with IDH wild-type malignant diffuse astrocytomas Fig. .Fig. 1GFUBP1 and CIC genes, which promote tumorigenesis and cell proliferation [1p/19q chromosome codeletion results from a balanced translocation of the short arm of chromosome 1 and the centromere region of chromosome 19 and leads to the subsequent deletion of other chromosome arms . It commferation , 31. In feration , 33.GTR is not always recommended for diffuse gliomas with IDH mutation and 1p/19q codeletion, especially for those located in the eloquent area. A previous study demonstrated that, in low-grade diffuse gliomas with IDH mutation and 1p/19q codeletion, GTR would not significantly prolong OS . CompareO6-methylguanine-DNA methyltransferase (MGMT) is a DNA damage repair protein that removes guanine alkylation and prevents apoptosis , 36. TheMGMT promoter methylation helps to improve EOR. In MGMT promoter methylated GBMs, intraoperative ultrasound, intraoperative MRI, and 5-aminolevulinic acid (5-ALA) fluorescence staining can more accurately determine tumor boundaries, reduce the false-negative rate, and, ultimately, improve EOR . Sharma Epidermal growth factor receptor (EGFR) is a tyrosine kinase, which is commonly activated or overexpressed in malignant astrocytoma, with the most common form of recombinant amplification being the EGFR variant type III (EGFRvIII) . EGFRvIIIn the past few years, 5-ALA has been established as an effective intraoperative tool to increase EOR in high-grade gliomas . Fontanap53 is one of the most well-known tumor suppressor proteins to date, involving virtually all cancers, including gliomas. TP53 gene mutation involves multiple regulatory factors and is believed to promote malignant progression of low-grade glioma . ATRX isCD133  is a membrane-bound glycoprotein that may be involved in cell differentiation and epithelial to mesenchymal transition and is a marker of human neural stem cells . A previIn addition to the molecular markers mentioned above, there are many other molecular variants associated with diffuse gliomas. Further study is necessary to explore the relationship between molecular biomarkers and tumor resection to improve therapeutic effects and patient prognosis.Based on the evidence mentioned above, molecular biology is, in fact, able to guide tumor resection to improve survival outcomes of patients with diffuse gliomas. Hence, preoperative prediction and intraoperative detection of molecular biomarkers are critical for glioma surgery. Several techniques have been applied to acquire both histological and molecular characteristics intraoperatively, including rapid frozen section, mass spectrometry, and real-time polymerase chain reaction, among others , 56. ExcMRI yields a significant amount of information about tumors. Recently, radiomics has emerged with the development of image feature extraction and machine learning techniques. Radiomics can automatically extract high-throughput and high-dimensional image features from medical imaging data aimed at obtaining more objective, quantitative, and invisible tumor features. Subsequently, these features could be combined with the results of molecular detection methods to establish prediction models to achieve accurate prediction before surgery , 59. BasIn summary, both preoperative and intraoperative techniques, including radiomics, real-time polymerase chain reaction, gap-enhanced Raman tags, molecular nanoprobes, and other fluorescence staining techniques based on molecular biomarkers, can provide valuable evidence of molecular biomarker expression and tumor margins, which could further affect the design and implementation of surgical strategies to treat diffuse gliomas. The development and application of these new techniques could establish a foundation for guiding surgical strategies with molecular biomarkers and further the progress of individualized medicine.The main limitation of the present literature review was that all studies were retrospectively designed. This was inevitable because no randomized controlled clinical trials have been conducted. Additionally, the number of studies that focused on the correlation between molecular biomarkers and EOR is limited, especially when taking functional area into consideration. Thus, the level of evidence for EOR recommendations based on molecular biomarkers is relatively low.The current study revealed that molecular biomarkers can inform the design of surgical strategies for diffuse gliomas. In the era of precision medicine, individualized rather than “one-size-fits-all” operative strategies developed by comprehensive consideration of functional status and molecular biological characteristics can maximize the survival benefit to patients, which would represent a major trend in the surgical treatment of diffuse gliomas in the future.


This article reviews the current understanding and management of abnormal uterine bleeding (AUB) in adolescents. It is hoped that this review will provide readers with an approach to the evaluation and treatment of mild to severe uterine bleeding. AUB is a common problem which has significantly adverse effects on an affected adolescent’s quality of life. The most common underlying condition in AUB in adolescence is anovulation. During the evaluation, pregnancy, trauma and sexually transmitted diseases must be ruled out, regardless of history. It should be kept in mind that AUB during this period may be the first sign of underlying bleeding disorders. Although observation is sufficient in the mild form of AUB, at the other end of the spectrum life-threatening bleeding may necessitate the use of high doses of combined oral contraceptives, intravenous estrogen and/or interventional procedures. Adolescents have frequent menstrual problems such as irregular menses, painful cycles and prolonged or heavy menstrual bleeding (HMB). Abnormal uterine bleeding (AUB) is defined as bleeding from uterine corpus that is abnormal in duration, volume, frequency and/or regularity. Due to immaturity of the hypothalamic-pituitary-ovarian (HPO) axis, AUB is common in adolescents ,2. FurthAlthough the age of onset of puberty has tended to decrease over the past few decades, the age of menarche has remained constant at 12-13 years . At presAUB might also be classified as acute or chronic. Acute AUB refers to an episode of heavy bleeding which is sufficient in quantity to require immediate intervention to prevent further blood loss. Abnormalities in quantity, regularity and/or timing in the last six months may all be defined as chronic AUB . UsuallyAUB in adolescents is a challenging and often neglected problem. Cycle to cycle variability, differences in menstrual hygiene, the wide variety of menstrual hygiene pads or tampons available, inconsistency in giving information about menstrual regularity and bleeding amounts make initial assessment of AUB even more difficult in these girls . PatientIn these girls, clinicians should evaluate the features of the menstrual cycle like a vital sign . An accuInitial screening for an underlying disorder of hemostasis in patients with excessive menstrual bleeding should be structured by the medical history. A positive screening result comprises the following circumstances:- Heavy menstrual bleeding since menarche- One of the following conditions:- Postpartum hemorrhage,- Surgery-related bleeding,- Bleeding associated with dental work.- Two or more of the following conditions:- Bruising, one to two times per month,- Epistaxis, one to two times per month,- Frequent gum bleeding,- Family history of bleeding symptoms.Patients with a positive screening test should be considered for further evaluation, including consultation with a hematologist and testing for von Willebrand factor and ristocetin cofactor.In intermenstrual bleeding, cervicitis and hormonal contraception may be implicated. In adolescents who do not respond to standard medical therapy, structural causes of bleeding should be excluded. When adolescents present with acute AUB, physical examination should focus on signs of acute blood loss and the etiology of bleeding. While tachycardia and orthostatic hypotension may be the only signs of severe anemia, it should be kept in mind that young patients will not present with clinical signs, despite severe anemia. While the presence of bruises and petechiae on the skin may indicate an underlying coagulation disorders, pallor may be seen due to anemia. In adolescents who are sexually active, trauma, foreign body, structural causes and pelvic inflammatory diseases can be investigated by pelvic and bimanual examination.Initial evaluation of adolescents presenting with acute AUB should include screening for pregnancy, anemia, bleeding disorders, iron deficiency and thyroid disease . CompletNeisseria gonorhhea and Chylamidia trachomatis infections with nucleic acid amplification tests.Since exogenous estrogen use may increase von Willebrand Factor concentrations into the normal range, it is necessary to perform the test either before starting hormone treatment or seven days after the end of treatment to prevent false negative results . If patiRoutine pelvic imaging is considered unnecessary since structural etiologies are rarely seen in this group. However, in the girls who do not respond to initial treatment, transabdominal ultrasonography may be more appropriate than transvaginal ultrasonography.Most adolescents need outpatient management and reassurance that their menstrual cycles would become cyclic and ovulatory over time. However, treatment is required when AUB causes anemia or impairs quality of life . In thesGirls with active, profuse, heavy bleeding (>1 pad per hour), presence of vital signs in conjunction with evidence of hypovolemia, orthostatic hypotension or hemoglobin (Hb) concentration <8 gr/dL due to bleeding are accepted as having severe AUB and should be hospitalized. If patients can tolerate oral intake, and in the absence of contraindications of estrogen treatment, monophasic combined oral contraceptive pills (OCP) containing 30-50 mcg ethinyl estradiol, can be used every 6-8 hours until bleeding diminishes, then taper to two and then one pill daily . If bleeAlthough it is known that nonsteroidal anti-inflammatory drugs (NSAIDs) decrease menstrual bleeding in premenopausal women, NSAIDs should not be prescribed to these girls because this therapy may exacerbate AUB due to underlying bleeding disorders. Tranexamic acid is an anti-fibrinolytic agent that has been shown to be as effective in decreasing menstrual blood loss as OCP and improved the quality of life in adolescents . Concomiin situ for 12-24 hours while other treatments are given. After the bleeding stops, the balloon of the Foley catheter is gradually and carefully emptied and completely withdrawn. There is a risk of uterine perforation, endometrial damage and infection risk with this method , micronized oral progesterone (200 mg/day) or norethindrone acetate (2.5-5 mg/day), which should be given for 12 days in every cycle .After acute menstrual bleeding ceases, these girls require treatment for long-term bleeding control. In addition to diet optimization and iron supplementation, hormonal treatments are used. Hormonal treatments include OCP, oral, injectable and implantable progesterone and the LNG-releasing intrauterine device (LNG-IUD). For OCP, continuous or extended-cycle regimes are recommended for stabilization of the endometrium. Combinations of 30-50 mcg of ethinyl estradiol and levonorgestrel or norgestrel are more effective in reducing bleeding than in low-dose and new generation progesterone-containing preparations. Depot medroxyprogesterone acetate is also used for long-term bleeding control. Since there is a risk of hematoma with intramuscular administration, subcutaneous injection is recommended. To reduce the likelihood of initial breakthrough bleeding, therapy is applied more frequently than the usual 12-week cycle . Since dAUB in adolescents may be acceptable at the beginning of the reproductive age when menstrual cycle regularity is not established, or may be the first sign of a severe underlying bleeding disorder. Girls with AUB should be evaluated with care and a wide differential diagnosis should be borne in mind. Medical therapy is usually an effective and sufficient treatment. Generally, adolescents respond well to therapy. Hematology consultation, imaging methods and clinical intervention should be considered in patients who do not respond to treatment.


During aging, the skin undergoes changes in architecture and composition. Skin aging phenotypes occur due to accumulated changes in the genome/epigenome, cytokine/cell adhesion, cell distribution/extracellular matrix (ECM), etc. Here we review data suggesting that tissue mechanics also plays a role in skin aging. While mouse and human skin share some similarities, their skin architectures differ in some respects. However, we use recent research in haired murine skin because of the available experimental data. Skin suffers from changes in both its appendages and inter-appendage regions. The elderly exhibit wrinkles and loose dermis and are more likely to suffer from wounds and superficial abrasions with poor healing. They also have a reduction in the number of skin appendages. While telogen is prolonged in aging murine skin, hair follicle stem cells can be rejuvenated to enter anagen if transplanted to a young skin environment. We highlight recent single-cell analyses performed on epidermis and aging human skin which identified new basal cell subpopulations that shift in response to wounding. This may be due to alterations of basement membrane stiffness which would change tissue mechanics in aging skin, leading to altered homeostatic dynamics. We propose that the extracellular matrix (ECM) may play a key role as a chemo-mechanical integrator of the multi-layered senescence-associated signaling pathways, dictating the tissue mechanical landscape of niche microenvironments in aging phenotypes. We show examples where failed chemo-mechanical signaling leads to deteriorating homeostasis during skin aging and suggest potential therapeutic strategies to guide future research to delay the aging processes. As skin ages, it undergoes physiological and pathological changes causing a decline in both structure and function . These cManifestations of the aging skin include rough skin textures, wrinkles, laxity, atrophy, pigmentary changes, loss of underlying fat, dry and itchy skin, inability to perspire sufficiently, hair graying, hair loss, thinning of nail plates amongst others . Recent Intrinsically aged skin appears dry and pale with fine wrinkles and increased laxity. This results from gradual physiologic changes include reductions of cell number, collagen production, blood flow, lipids, and rete ridges . ExtrinsSolar elastosis, characterized by the replacement of normal elastic fibers with a disordered mass of elastotic material near the dermal-epidermal junction, is the hallmark of photodamaged dermis . Senile Within the aging mouse skin, the cell number and turnover rate decrease across all cell types , which iAdult skin SC are vital for replacing cells in tissues, but their capacity declines with age. SC are regulated by both macroenvironmental signals  and theiTissue mechanics  can provThe skin cells interact dynamically with the basement membrane (BM), ECM, and the dermis to shape the structure and function of the skin . The derRecent single-cell analyses identify new sub-populations of basal cells that specifically localize at the top or bottom of rete ridges , suggestRete ridge reductions and tissue mechanical landscape changes in aging skin can either be the cause or consequence of changes in these basal layer sub-populations. Additionally, the basement membrane (BM) adjacent to HFSC serves as an arrector pili muscle (APM) niche , which tThe changes in ECM synthesis, assembly and dampened cellular response to mechanical stimuli in aged skin lead to low proliferation, discontinued migration, prolonged cell-cycle arrest, and eventually cell death . KruglikWound healing in a healthy, aged individual is delayed but not defective . This isPerturbation to tissue mechanics or disruption of tensional homeostasis impacts physiological functioning of the skin, including hair cycling and wound healing .Generally, increasing skin tension or stiffness leads to higher cell activity and ECM synthesis. Molecules responsible for mechanotransduction are also important in regulating tensional homeostasis. Epidermal-specific deletion of integrin or focal adhesion kinase (FAK) results in disfigured hair follicles and dysregulated hair cycle propagation . ActivatThe impact of skin “loosening” during aging can be deduced from the effects of mechanical force on the homeostasis of HFSC. The amount and duration of skin mechanical stretching result in HFSC proliferation . This deExternal mechanical forces such as hair plucking can also trigger the immune response-mediated regenerative process. Properly arranged hair plucking can trigger an efficient regenerative response mediated through a two-step immune response cascade, called quorum sensing . These eAlthough currently there is no prominent strategy for developing new drugs against skin aging, there are a few chemical and mechanical approaches that have demonstrated potential.Platelet-rich plasma (PRP) has been adopted to treat many degenerative disorders including hair loss  with reaReplenishing effective growth factors or activating specific downstream genes such as Wnt-follistatin and follistatin-like 1 protein have been tested as a treatment for alopecia . PharmacThe adipocytes in the dWAT have high plasticity and undergo reversible dedifferentiation, in which adipocyte-derived preadipocytes trans-differentiate into myoblasts and are involved not only in the physiological hair cycle but also under pathological conditions such as hypertrophic scarring, systemic sclerosis and androgenetic alopecia . During Although the effectiveness of stretching-induced HF activation is less pronounced in aging mice , interesWe review the physiological changes associated with skin aging  and highThe original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s.Written informed consent was not obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article.CCC and SPW contributed more to the clinical aspect. HICH, ML, and CMC contributed more to the basic research elements. All authors contributed to the writing, organization, and editing of the manuscript. The manuscript was proofread by Dr. R. B. Widelitz.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.