As the leading human papillomavirus (HPV)-related cancer, oropharyngeal cancer places a significant burden on patients, families, and health systems. Techniques to easily and quickly test people for HPV through non-invasive means  could, in principle, help us better understand this disease, prevent it, and treat it. However, there is currently no standardized methodology for testing saliva or blood for HPV, and such testing is not a part of routine clinical practice. In this review, we discuss and compare some of the collection and testing platforms that researchers have studied to date. We also evaluate the potential strengths and limitations of these technologies for addressing unmet needs in specific clinical contexts.The burden of human papillomavirus (HPV)-related oropharyngeal cancer (OPC) has risen, now representing the most common HPV-related malignancy. For years, researchers have explored the utility of measuring HPV-related markers from mouth, throat, and blood samples, often with the aim of gathering more information about an existing HPV-related tumor in a given patient. We review the widely varying methods for collecting and testing saliva and blood samples and offer guidance for standardizing these practices. We then review an array of clinical contexts in which non-invasive testing holds the most promise for potentially addressing unmet needs. In particular, such testing could help clinicians and researchers monitor the effects of vaccination and treatment. Meanwhile, due to the currently incomplete understanding of how carrying HPV relates to infection and subsequent oncogenesis, non-invasive testing methods may not be suitable for the screening setting at this time. Human papillomavirus (HPV)-associated oropharyngeal cancer (OPC), with an estimated 12,600 new cases per year in the United States, now outpaces all other HPV-associated malignancies by incidence  . Across Unlike many other cancers, OPC is associated with a distinct, well-characterized, relatively homogeneous etiology in most cases (>70%): HPV infection . This diIn this review, we compare the methodologies that researchers have most commonly examined for sample collection and analysis of HPV among selected studies in recent literature. Among the expanse of research available on the topic of non-invasive HPV testing, we chose to focus our discussion on later studies (2017 and onward). While we chose, when possible, to discuss studies with large sample sizes, we also consider smaller studies that offer exceptional insights . We limit our scope to the most commonly studied sample collection and testing methodologies. We discuss the value that HPV testing may offer in a range of specific public health and clinical scenarios related to HPV-associated OPC.Oral rinse is a common method for collecting samples from the mouth and throat . Other aAmong oral rinse sample studies, there is substantial variation in specific approach to this collection method. Generally, participants held the collection fluid  in their mouths for 15–30 s ,17,18. TWhat is unclear, given these varying methodologies, is whether some methodologies detect more HPV due to greater sensitivity or due to lower specificity. That mystery leads us to a dilemma: what constitutes clinically meaningful HPV infection? Does the mere presence of HPV-related material in the mouth or throat mean that an individual has a potentially pathogenic infection? The fact that several studies demonstrated higher HPV rates in oral rinse samples compared to brushing and swabbing samples may indeed indicate that presence of HPV in oral rinse is not the same as infection of cells that may be collected with brushes or swabs. This question warrants further research.Future studies involving oral HPV biomarkers should provide ample detail relating to sample collection methodologies to allow for greater standardization and comparability across studies. Investigation involving head-to-head comparisons of varying oral rinse approaches is an unmet need and may help to provide insight on the question of viral presence versus persistent infection.Investigators performed HPV detection and, in some cases, quantification, using polymerase chain reaction (PCR)-based molecular analysis. Primers were designed to identify one or more of the HPV E6, E7, and L1 oncogenes. Investigators commonly used the Roche Linear Array HPV genotyping platform for non-quantitative HPV detection. Some studies incorporated reverse transcriptase (RT)-PCR, quantitative PCR (qPCR), or a combination of the two (RT-qPCR), while others made use of the more recently developed droplet digital PCR (ddPCR) method . AlthougAlthough less common than molecular testing of mouth and throat samples, there has been some exploration of HPV-directed antibodies in these samples . We addrWe observe two general approaches to serum testing: molecular analysis of circulating tumor DNA (ctDNA) and enzyme-linked immunosorbent assay (ELISA)-based analysis of HPV-targeted antibodies. In a study that compared ELISA-based detection of E6 antibodies with oral HPV16 DNA detection, nominal sensitivity of the antibody test was substantially higher (88% versus 43–51%), with similar specificity (≥98%) ,26,27. ASensibly, studies aimed at understanding the global epidemiology of HPV infection in the absence of a cancer diagnosis make use of mouth and throat testing rather than the slightly more invasive blood testing. Estimates of the prevalence of HPV genetic material in the mouth and throat in relatively unselected populations across geographies range from 1% to over 15% ,31,32,33Interestingly, one study demonstrated that the concordance of HPV presence and strain between bodily sites (mouth versus penis versus anus) was low . This fiBroad epidemiological studies using non-invasive HPV biomarker testing could reveal yet-unrealized risk factors for HPV-related disease. For example, we observe that the prevalence of mouth and throat HPV seems to be higher in individuals undergoing tonsillectomy compared to other settings . RoughlyParker and colleagues demonstrated that both mouth/throat and serum HPV-directed antibodies can offer information that correlates to some degree with timing since HPV vaccination . In theiKey issues that must be addressed to assess the utility of screening healthy individuals for the presence of HPV in saliva or serum include how results would impact clinical decision-making and whether screening could be cost-effective.Although, as expected, carrying oral HPV is associated with a greater risk for OPC (nearly 50 times the odds for a person carrying HPV16 versus someone who does not) , the incOlder non-invasive biomarker studies helped to establish the basis for our current understanding of risk factors for HPV-related oropharyngeal cancers. Knowledge gained from this scholarship could help determine which groups might be the most appropriate candidates for screening programs. Included on the lengthy list of (now well-accepted) risk factors determined by these studies to increase the risk of OPC are male sex, increased number of lifetime vaginal sex partners, and increased number of lifetime oral sex partners ,39. ThesInterestingly, the results of one more recent study, consistent with prior work, indicate that carrying oral HPV does not correlate with abnormal cytologic findings ,38. ThisAlthough the approach of using serum antibody testing as a screening tool is less common than testing orally collected specimens in the literature, there is some evidence that this strategy could be associated with higher accuracy compared with oral testing . HoweverIn all, non-invasive HPV detection would have a high bar to meet in terms of cost-effectiveness, given that a minority of patients with evidence of HPV infection will go on to develop OPC and that there are some open questions about the utility and accuracy of testing methods in this setting. Before (and if) non-invasive HPV testing could be useful in screening, a greater understanding of the implications of carrying HPV  would be needed.®  platform has demonstrated clinically meaningful utility in tracking response or outcomes to chemoradiotherapy [While quantifying HPV infection through non-invasive testing at OPC diagnosis does not seem to offer much prognostic value, there are promising signals of benefit associated with non-invasive HPV testing as part of monitoring treatment effect . The comotherapy . Individotherapy ,42. Thes® technology has also shown potential in the setting of surveillance following completion of definitive therapy. The test demonstrated a negative predictive value of 100% in anticipating disease-free status among individuals with undetectable HPV ctDNA at all post-treatment timepoints and demonstrated a 94% positive predictive value for recurrence among individuals with two consecutive positive results after completing therapy [® trial have been observed in other studies using different PCR-based technologies and other collection methods (including non-invasively collected sample from tumor brushings) [Our prior work has demonstrated that the natural course of salivary HPV-targeting antibodies is to decline over time following completion of definitive therapy for OPC . Beyond  therapy . The sec therapy . Similarushings) ,19,21. Sushings) . A numbeushings) .Non-invasive HPV testing has the potential to be of great use in certain public health and clinical contexts related to HPV-associated OPC. However, greater understanding of the pathogenic mechanisms linking HPV exposure to HPV infection and those linking HPV infection to OPC tumorigenesis are prerequisites to fully harnessing the value of non-invasive testing. For HPV testing to be useful in the screening setting, clinicians would require additional information besides the presence or absence of HPV genetic material or of immune response to HPV. Detecting potentially oncogenic infection using markers of gene expression  is a ripe area for study in the screening setting. Once we can appreciate which markers are most meaningful for predicting oncogenesis, we will be in a position to conduct head-to-head trials to understand which tissue collection and laboratory testing methodologies provide the most accurate measures of those markers. After comparative studies have provided indications of optimal collection and testing techniques, clinician researchers will then be able to work out how best to use those diagnostic tools to guide clinical decisions in the screening setting. In sum, there is currently insufficient data to support the use of non-invasive HPV testing in the screening setting. Clinical data demonstrating improved outcomes resulting from non-invasive screening would be a requirement for this strategy to prove useful. At present, the clinical implications of positive screening test results are unclear.Testing immunogenicity following vaccination can help optimize vaccine development and public health strategies aimed at vaccination. We recommend that future vaccine clinical trials incorporate immunogenicity testing to understand if some groups of patients could benefit from more or fewer doses. Trialists could also attempt longer follow-up  to gain a greater understanding of how markers of immunogenicity correlate with observed risk of HPV infection and HPV-associated malignancy.Monitoring HPV levels during definitive therapy could, in the future, help personalize treatment. We could hypothesize, for example, that individuals whose HPV markers drop precipitously early on in definitive therapy might be candidates for de-escalation . Inversely, those with persistently elevated HPV markers might benefit from a more extended course of definitive therapy or novel adjuvant regimens. Incorporating non-invasive HPV testing as part of routine monitoring in clinical trials studying definitive therapy can help us uncover such fresh approaches. Incorporating non-invasive HPV testing into follow-up after definitive therapy in these trials could offer insight into how such testing could help detect recurrences earlier. Even only with currently available data, we believe that there is a role for plasma HPV ctDNA platforms as an adjunct to traditional response metrics  in the context of monitoring response and surveilling for recurrence. Although research to date has focused on treatment with curative intent, future studies should examine the utility of monitoring HPV in the recurrent/metastatic setting. Especially as our understanding of how HPV causes OPC improves, non-invasive HPV testing promises to offer innovations in the field of HPV-related OPC.


In natural vision, objects appear at typical locations, both with respect to visual space  and other objects . Recent studies have shown that object vision is strongly adapted to such positional regularities. In this review we synthesize these developments, highlighting that adaptations to positional regularities facilitate object detection and recognition, and sharpen the representations of objects in visual cortex. These effects are pervasive across various types of high-level content. We posit that adaptations to real-world structure collectively support optimal usage of limited cortical processing resources. Taking positional regularities into account will thus be essential for understanding efficient object vision in the real world. Many natural behaviors crucially depend on accurately perceiving objects in the environment. Consequently, understanding object vision has been a core endeavor in cognitive neuroscience for many years, and recent decades have yielded exciting insights into how the human visual system processes various types of objects –5. By anAlthough it has already been well established that such real-world positional regularities furnish observers with cognitive strategies that support effective behaviors  translate to typical absolute locations within the visual field (in retinotopic coordinates). As a consequence, as we sample visual information from the scene, many objects - until directly fixated - are projected to specific locations in the visual field. Owing to their typical within-scene locations, for example, lamps tend to occur in the upper visual field and carpets tend to occur in the lower visual field .multivariate pattern analysis  compared to atypical locations  ,14. Notacontinuous flash suppression (CFS), interocular suppression renders a visual stimulus invisible for several seconds before it can be detected, and the time until it becomes visible  is considered to be a sensitive measure of the detectability of an object [Performance benefits for typically positioned objects are even observable in simple detection tasks. In n object ,17. In sn object  and facen object  break suThat the typical absolute location of an object can impact upon its basic perceptual processing prompts the interpretation that these effects reflect changes in neural tuning properties. Evidence supporting this interpretation comes from electrophysiological studies which show that object representations are modulated by the position of the object in the visual field very soon following stimulus onset. Within the first 140 ms of vision, representations of both objects  and facereceptive field (RF) organization of category-selective regions of occipitotemporal cortex. Studies using population receptive-field mapping [If the effects of typical positioning do not reflect post-perceptual feedback, how are they implemented within the visual architecture? One possible explanation comes from research exploring the  mapping ,23 have For instance, RFs in word-selective cortex of English speakers are comparably small, biased towards foveal vision, and extend further horizontally than they do vertically ,25. ThisA similar link between RF position and content-specific visual field biases is found in face- and place-selective cortices: face-selective regions have small RFs close to the center of gaze, consistent with the foveal processing necessary for individuating faces –31. By cTaken together, these studies suggest that RF properties of high-level visual cortex are tightly linked to the characteristic spatial distribution of visual objects. Importantly, since these studies typically use meaningless checkerboard stimuli to map RF properties, their findings demonstrate that visual field biases exhibited by category-selective regions are evident even in the absence of any categorical processing demands. That is, when no categorical information is present in the stimulus, the field of view of a region cannot be adjusted based on content-specific feedback processes. These population RF mapping studies therefore corroborate the notion that our extensive experience with real-world environments influences neural tuning independently from top-down feedback .The conjoint tuning to object category and visual field location yields measurable benefits in perceptual performance: across individuals, RF sizes in face-selective and word-selective cortex, respectively, predict face recognition performance  and readWhich level of representation is enhanced when objects are positioned in their typical real-world locations? The fact that the effects of typical positioning are observed in high-level visual cortex suggests that they are not caused by visual field biases in low-level feature processing. However, these regions represent a multitude of object properties ranging from object-associated mid-level attributes  to categorical object content. Because these organizations are spatially entwined ,35, it iTo summarize, recent findings provide convergent evidence that the cortical object-processing architecture is tailored to the spatial distribution of objects in the real world. Consequently, object perception varies systematically across the visual field, with more efficient processing for individual objects appearing in their typical absolute locations in the world.Natural environments are inherently structured not only in terms of the absolute locations of objects within the environment, but also in terms of the relative positioning of objects with respect to each other. For example, objects in a dining room typically appear in specific relative locations  . Such stExactly as the typical absolute positioning of objects impacts on basic levels of perceptual processing, so too does their typical relative positioning: under CFS, observers detect groups of typically arranged objects  faster than groups of atypically arranged objects   Figure , even whBeyond basic detection, perceptual benefits associated with typical relative positioning are found in explicit identification and recognition tasks, where typically positioned groups of objects –41 and iGestalt has been associated with the grouping of different pieces of visual information. Interpreted in a similar way, the studies reviewed above could reflect the grouping of objects when they appear in accordance with real-world structure.Why are typically positioned object arrangements represented more efficiently? One possibility is that multiple objects arranged in their typical relative positions are represented as a group rather than as multiple individual objects, thereby reducing the descriptive complexity of multiobject representations. For instance, a table flanked by chairs with a lamp above and carpet below may be represented as a single ‘dining group’, rather than as multiple individual objects. This idea is reminiscent of the study of grouping in low-level vision , where tintegrative processing of objects. This would lead to enhanced activations in visual cortex for objects in typical versus atypical relative positions. Such enhanced activity has indeed been observed for objects that co-occur in real-world scenes [This assertion has been tested at the neural level, where grouping is mediated by d scenes , objectsd scenes –54, faced scenes ,56, and d scenes ,58.multivoxel combination analysis  allows testing of whether a similar principle underlies the representation of multiple objects in visual cortex. When multiple objects are processed independently, a linear combination of the individual-object patterns  accurately predicts the multiobject pattern [Although these studies are in line with integrative processing, increases in overall activity may partly reflect other factors such as greater attentional engagement with the typically positioned objects. Therefore, as an alternative measure of integrative processing, recent studies have investigated how relative object positioning affects the similarity of multivoxel response patterns in the absence of overall activity differences –61 Figu. These s pattern –66. HoweIn one such study , pairs oAt a mechanistic level, these effects are parsimoniously explained by the involvement of additional neural assemblies that exclusively represent typically positioned object groups. Through extensive exposure to concurrent objects appearing in typical relative locations, specialized neural assemblies may become tuned to the concerted presence of these objects –69: consAnother open question concerns the level of representation at which object information is grouped. Given that the effects of typical relative positions emerge in anterior parts of LOC , it is pTogether, these findings suggest that the perceptual benefits observed for typically positioned multiobject arrangements reflect the grouping of multiple individual object representations. This grouping mechanism may be of particular relevance in the context of complex real-world scenes, wherein individual objects often form meaningful arrangements, such that integrating their individual representations into a higher-order group representation may serve to effectively simplify scene analysis.The findings reviewed here collectively suggest that sensitivities to real-world spatial structure are ubiquitous in high-level vision: we can observe them in the neural representations of both individual objects and multiobject arrangements, as well as across a diverse range of high-level visual stimuli. We posit here that a common purpose underlies these various adaptations to real-world structure: namely, the optimal use of limited cortical resources. In the following we first reflect on the nature of cortical resource limitations, and then outline how adaptations to both typical absolute locations and typical relative locations allow us to efficiently represent objects in the context of these limitations.A unifying commonality across perceptual and cognitive systems is their restricted capacity to process multiple entities simultaneously ,76. IndeIn the context of real-world vision, the representational deficit imparted by interobject competition yields pessimistic predictions: most natural scenes comprise a large number of objects , many ofFirst, adaptations to the typical absolute locations of objects can reduce interobject competition by increasing the precision of neural representations. Classical theories of object recognition , 86 typiThe preferential processing of particular objects by separate, spatially tuned neural populations is further apparent at the level of visual categories. In high-level visual cortex, spatially distinct regions that process information for various visual categories  can be differentiated both in terms of how they sample visual space ,31 and iSecond, adaptations to the typical relative locations of objects may reduce interobject competition by effectively reducing the number of objects competing for resources. Where a visual system with infinite processing resources could afford to process all objects in parallel , the biological constraints on the human visual brain are such that grouping objects  becomes an efficient way to reduce the number of individual items competing for representation. Although the representations of object groups are still subject to resource-capacity limitations, competing for resources at a group level results in fewer representations in direct competition with one another, and consequently this competition is less detrimental than when representing the objects individually.The notion that integrating information carried by co-occurring objects reduces interobject competition is borne out by neuroimaging work showing that object-category responses  are stronger when concurrently presented competitor objects can be grouped based on their typical positioning  than when they cannot be grouped based on their positioning   Figure . NotablyIn sum, adaptations to real-world structure can reduce neural competition between objects in multiple, complementary ways: (i) adaptations to typical absolute locations reduce processing overlap between representations precisely tuned for particular objects appearing at particular locations, and (ii) adaptations to typical relative locations allow multiobject grouping, thereby reducing the number of objects competing for processing. Together, these adaptations simplify the neural code for scene analysis. The resulting simplification of scene representation contributes to the efficiency of human performance in naturalistic tasks, such as visual search in scenes ,11,83,84The current review underscores the fundamental and intrinsic link between the structure of natural environments and our visual perception of the world. The adaptations reviewed here support effective object processing in the real world: by capitalizing on positional regularities, the visual brain is able to optimally represent complex multiobject scenes. To conclude, we briefly revisit four key insights of our review and delineate how these insights inspire future research in object vision and beyond (see Outstanding Questions).First, adaptations to real-world structure play a key role in the perception and representation of various types of high-level content, including diverse everyday objects , human beings , social and functional action relationships , and written text. This not only shows that high-level vision is inseparably linked to real-world structure but also highlights that positional regularities play a key role in many everyday tasks, from action understanding to reading.Second, adaptations to real-world structure arise in both cognitive and perceptual systems. Most interestingly, they not only influence high-level processes such as recognition and working memory, but also operate at the very early stages of visual processing, even determining how quickly we detect an object in the first place. This shows that real-world positional regularities exert a more fundamental influence than was previously thought: not only do they equip humans with cognitive strategies to explore the world in smart ways, they also support the efficient perceptual parsing of natural information.Third, the study of positional regularities in high-level vision could advance current efforts in modeling the human visual system. The far-reaching impact of real-world structure suggests that object vision cannot be fully understood without taking real-world structure into account. The recent insights thus urge a consideration of positional regularities in neural models of object processing. Interestingly, explicitly considering real-world structure may not only help to understand the biological brain but also fuel developments in computer vision .Finally, the importance of real-world structure supports neurocognitive research that pushes towards more naturalistic approaches to vision: only by studying vision under conditions that more closely mimic the properties of real-world environments will we come closer to understanding how we efficiently select, recognize, and ultimately extract meaning from a complex visual world.


During their development and overall life, mesenchymal stem cells (MSCs) encounter a plethora of internal and external stress signals and therefore, they need to put in action homeostatic changes in order to face these stresses. To this aim, similar to other mammalian cells, MSCs are endowed with two crucial biological responses, autophagy and senescence. Sharing of a number of stimuli like shrinkage of telomeres, oncogenic and oxidative stress, and DNA damage, suggest an intriguingly close relationship between autophagy and senescence. Autophagy is at first reported to suppress MSC senescence by clearing injured cytoplasmic organelles and impaired macromolecules, yet recent investigations also showed that autophagy can promote MSC senescence by inducing the production of senescence-associated secretory proteins (SASP). These apparently contrary contributions of autophagy may mirror an intricate image of autophagic regulation on MSC senescence. We here tackle the pro-senescence and anti-senescence roles of autophagy in MSCs while concentrating on some possible mechanistic explanations of such an intricate liaison. Clarifying the autophagy/senescence relationship in MSCs will help the development of more effective and safer therapeutic strategies. Mesenchymal stem cells (MSCs) are the most widely utilized adult stem cells in clinical trials . ThorougSenescence, biologically described as a cellular condition in which cells have lost the proliferative capacity, yet maintaining their metabolic activity, is a genetically based program responding to stress signals that avoids damaged cells to further proliferate, acting as a powerful tumor suppressive mechanism . As reviATG (autophagy-related) genes and ATG proteins; their first identification in the yeast (Macroautophagy (hereafter referred to as autophagy and the focus of this review) represents a crucial path for the maintenance of cellular homeostasis under both physiologic and stressful situations since upon activation it sustains cellular survival thanks to the preservation of suitable metabolic functions, bioenergetic levels and amino acid pools. It is a degradation process of cellular own elements relying on the lysosomal compartment, representing a fundamental protective answer to tough situations like nutrient deprivation, where active recycling of cellular components are needed to guarantee energy homeostasis . In addihe yeast  was follhe yeast . A macrohe yeast . An elonhe yeast , 2004. DThe intricate relationship between autophagy induced by diverse extra- or intracellular stimuli and the molecular targets that influence MSC proliferation, differentiation, and stemness has been reviewed elsewhere . BrieflyThe main view of autophagy’s impact is an efficacious anti-senescence role implicating various pathways, whose principal players are the  target of rapamycin (mTOR), insulin-like growth factor (IGF) binding to insulin-like growth factor receptors (IGF1R), adenosine monophosphate-activated protein kinase (AMPK) and p53 . Indeed,More recent investigations have confirmed that autophagy is requested for sustaining the stemness and differentiation properties of stem cells. Garcia-Prat et al. described a critical role for basal autophagy in the maintenance of an immature stage in satellite cells, and unsuccessful autophagic activity promoted cell senescence defined by numerical and functional decrease of these cells .Along this line, it was found that autophagic activity of old bone marrow-derived MSCs was diminished in comparison with young MSCs . AuthorsD-galactose-mediated MSC senescence  expression was found to protect senescent MSCs kept under conditions of hypoxia by means of an up-regulated autophagic flux, thus augmenting the survival of senescent MSCs after myocardial infarction transplantation . Also, hLastly, a few reports described oncogene-induced senescence (OIS) in MSCs in conjunction with disease manifestation. In patients suffering from systemic lupus erythematosus, for example, leptin and Neutrophil-Activating Peptide 2 sustained MSC senescence through activation of the PI3K/AKT signaling . AnotherFrom these previous data, it appears that autophagy acts in MSCs as either a pro-senescence or an anti-senescence process, thus if and in what manner autophagy directs MSC aging remains elusive .Although the molecular bases underpinning senescence, particularly those overlapping with autophagy, are yet poorly comprehended, reconciling these antithetic phenomena would be feasible only by speculating that autophagy may regulate a number of targets oppositely acting to modulate cellular senescence in MSCs. Interestingly, recent studies disclosed distinct functions of general versus selective autophagy in the control of senescence, partially solving seemingly conflicting evidence concerning the relation between these two fundamental homeostatic responses to stress stimuli. In model cells other than MSCs, Kwon et al. suggested the interesting possibility that such a dual role might be context and time dependent as well as specifically depend on the type of autophagy, general versus selective, involved .According to this model, under normal conditions, general autophagy would act as an anti-senescence process by preserving cellular homeostasis. Upon situations of induced stress, early action of general autophagy would also play the role of a homeostatic response, thus prevalently anti-senescent . However, general autophagy exerted in cells that have already initiated a senescence process can become pro-senescent, in the sense that it can sustain viability of senescent cells. Indeed, senescent cells cannot dilute toxic byproducts as they do not undergo mitosis and they secrete a number of factors that can induce endoplasmic reticulum stress; in these conditions, autophagy induction could counteract the risk of proteostasis disruption and avoid cell death . AccordiIn the case of selective autophagy, when only a certain type of substrates is degraded, the resulting role on senescence would depend on the specific substrates and autophagic receptors involved. While looking for regulators of cellular senescence, So at least three elements, i.e., the context, time of action and type of autophagy involved appear to constitute the frame in which autophagy can result either pro or anti-senescence in MSCs, as depicted in When tissue homeostasis is disrupted due to MSC senescence the possible shortcoming is twofold: a loss of repairing capability caused by decreased self-renewal/differentiation abilities and a detrimental microenvironment modulation by senescent MSCs due to secretion of pro-inflammatory and matrix-degrading molecules contained in the SASP. Both have important clinical implications, so clarifying the autophagy/senescence relationship in MSCs might have an impact for the development of more effective and safer therapeutic strategies.in vivo but also their aging in vitro upon culture expansion poses a tangible burden and should be counteracted. Among possible druggable pathways, autophagy manipulation during MSC expansion has been proposed through the employment of FDA-approved drugs like rapamycin and its derivatives (As an example, the regulation of autophagy in MSCs exemplifies a conceivable strategy which, influencing MSC characteristics, may hit their regenerative potential, both in terms of differentiation properties and engraftment ability . Activativatives , which mivatives .These and future studies on relevant targets and small molecules leading to the control and maintenance of optimal levels of autophagy might open up the way to new strategies for improving MSC transplantation.RR and CG conceived and wrote the review. EV cooperated in bibliographic searches and table and figure 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.


The etiology of inflammatory bowel disease (IBD) is complex but is thought to be linked to an intricate interaction between the host’s immune system, resident gut microbiome and environment, i.e., diet. One dietary component that has a major impact on IBD risk and disease management is fiber. Fiber intakes in pediatric IBD patients are suboptimal and often lower than in children without IBD. Fiber also has a significant impact on beneficially shaping gut microbiota composition and functional capacity. The impact is likely to be particularly important in IBD patients, where various studies have demonstrated that an imbalance in the gut microbiome, referred to as dysbiosis, occurs. Microbiome-targeted therapeutics, such as fiber and prebiotics, have the potential to restore the balance in the gut microbiome and enhance host gut health and clinical outcomes. Indeed, studies in adult IBD patients demonstrate that fiber and prebiotics positively alter the microbiome and improve disease course. To date, no studies have been conducted to evaluate the therapeutic potential of fiber and prebiotics in pediatric IBD patients. Consequently, pediatric IBD specific studies that focus on the benefits of fiber and prebiotics on gut microbiome composition and functional capacity and disease outcomes are required. Inflammatory bowel disease (IBD) is characterized by chronic, relapsing inflammation of the gastrointestinal (GI) tract. There are two main subsets of IBD: Crohn’s disease (CD), which affects any part of the GI tract but is primarily found in the terminal ileum and cecum, and ulcerative colitis (UC), which affects only the colon. The incidence and prevalence of IBD is rising in a concerning fashion, particularly in children .It appears that one of the strongest determinants of IBD risk is a family history of the disease , althougPresently, there is no known cure for IBD. Therefore, current therapies are directed at controlling symptoms and maintaining disease remission through the use of immunomodulatory medications that unfortunately have side effects and varying success rates. Consequently, novel therapies are in high demand, with alternative and complementary approaches, particularly dietary and gut microbiome-targeted therapeutic approaches, gaining validity and popularity . More weIn this narrative review, we discuss the various types of fiber and prebiotics and the benefits they have on human health, the impact low fiber intakes may have on IBD pathogenesis and the suboptimal fiber intakes observed in pediatric IBD patients. We also provide an overview of the studies that have been conducted in adult IBD patients, as presently no relevant pediatric studies have been conducted, describing the impact fiber and prebiotic interventions have on disease outcomes and the gut microbiome.Dietary fibers (DFs) are commonly known as nondigestible carbohydrates that confer a health benefit to the host. The exact definition of fiber is still a matter of debate and is continuously evolving due to advances in the field and updates to international guidelines for food product definitions . The difMost countries’ authorities align with the Codex Alimentarius Commission (CAC) definition established in 2009, where DFs are defined as edible carbohydrate polymers with ten or more monomeric units that are resistant to endogenous digestive enzymes and thus are neither hydrolyzed nor absorbed in the small intestine of humans . The CACDFs are subdivided into either polysaccharides, such as non-starch polysaccharides (NSP), resistant starch (RS) and resistant oligosaccharides, or into insoluble and soluble forms ,9. SolubBased on the physiochemical characteristics of DFs it has been suggested that, even as a secondary effect, all fibers positively shift the gut microbiota composition conferring a general health benefit to the host . Howeverβ-glucans, arabinoxylan oligosaccharides, xylo-oligosaccharides, soy bean oligosaccharides, isomalto-oligosaccharides and pectin [Established prebiotics with the most extensively documented health benefits include inulin-type fructans  and oligofructose), galacto-oligosaccharides (GOS) and lactulose ,14. Othed pectin . Prebiotd pectin ,15. Subsd pectin .DF intake is notably different across industrialized and unindustrialized countries around the world, with inhabitants of rural communities consuming up to seven times more fiber than typical Western countries due to increased intake of fibrous plants . WesternInterestingly, several population studies and meta-analyses have demonstrated a beneficial effect of DFs in the reduction of disease risk, including cardiovascular disease, diabetes, metabolic syndrome, obesity, cancer, diverticular disease, IBD and functional intestinal disorders ,26,27,28n = 130) were matched to healthy controls (n = 202) to evaluate dietary intakes 1 year prior to diagnosis. Similarly, higher intakes of fish, fruits, vegetables and fiber were shown to be protective. Additionally, a higher ratio of omega-3/omega-6 fatty acids was significantly associated with a reduced risk of CD [Dietary components, such as fiber, have long been implicated in the pathogenesis of IBD; however, efforts to identify the specific dietary factors responsible have been challenging. Several studies have been conducted to help shed light on the complex interactions that exist between fiber and IBD risk during childhood and adolescence. A study utilizing data collected as part of the Nurses’ Health study II  was undertaken to determine whether adolescent diets were associated with risk of CD and UC. The effects of dietary patterns, such as a prudent  or Western  diet, as well as individual foods or nutrients, were examined. Adolescents with the highest intakes of fish, fruit and vegetables (prudent pattern) had a 53% reduced risk of developing CD. The dietary components with the greatest influence on lowering CD risk were higher fish and fiber intakes. There were, however, no associations between adolescent diet and UC risk . In a cask of CD . This grsk of CD . Notablysk of CD .The findings from these studies suggest that fiber intake, particularly from fruits and vegetables, protects against the development of CD. To date, the fiber specific studies in UC patients are less convincing. The associations between fiber and IBD risk may, however, be confounded by the fact that individuals consuming higher intakes of fiber, fruits and vegetables are likely concurrently consuming less animal fats and proteins, which are inversely associated with IBD risk. Additional research should focus on demonstrating what fiber types provide protection irrespective of other dietary components and whether fiber interventions can help reduce IBD incidence in high-risk children and adolescents.The majority of the studies conducted to assess how fiber impacts IBD risk in pediatrics have been conducted retrospectively in children or adolescents that had already been diagnosed with IBD rather than prospectively following children up over time. It is possible that dietary intakes, including fiber consumption, may change leading up to and after IBD diagnosis, making the dietary data collected in these studies less reliable in helping demonstrate whether fiber influences IBD pathogenesis. Large prospective longitudinal studies such as the Genetic Environmental Microbial (GEM) project, which is actively recruiting first degree relatives of CD patients to identify triggers of CD, are desperately needed to help better define how factors such as diet, genetics and the gut microbiome contribute to IBD risk .p < 0.05) and also significantly lower than children and adolescents without IBD  [n = 89; 55% with CD) in relation to healthy controls (n = 159). Children with UC had significantly lower fiber intakes and children with CD had significantly lower fruit intakes than healthy controls [DF intakes in pediatric IBD patients are generally considered to be suboptimal when compared to nutritional guidelines or children and adolescents without IBD. In a cross-sectional study of 57 pediatric CD and 11 pediatric UC patients , diet adequacy was assessed by comparing usual intakes with dietary recommendations and healthy control intakes. It was demonstrated that pediatric IBD patients had DF intakes that were significantly lower than the recommended dietary allowance  . In a st < 0.05) . Sila ancontrols . In a stcontrols .The rationale behind why pediatric IBD patients consume less fiber is likely multifactorial. However, IBD patients are often discouraged from consuming fiber-rich foods, especially during an exacerbation of disease, out of fear of causing further bowel irritation. Some patients have also reported worsening of symptoms due to consumption of high-fiber foods . A surven = 1130) and UC (n = 489) patients aimed to demonstrate whether fiber intakes were associated with disease flare over a 6-month period. They observed that patients with CD, but not UC, who continued to consume high-fiber foods were around 40% less likely to have a disease relapse compared to those that avoided these foods. It was outlined in this study that around 30% of patients avoided DF completely, but it was not clear if this was due to medical advice or personal preference. Interestingly, they also identified that individuals with longer disease duration and a history of surgery and hospitalization also had lower fiber intakes [The insufficient fiber intakes observed in children with IBD are important to consider as evidence is beginning to emerge suggesting that inadequate fiber intakes may have detrimental effects on disease course. A study conducted in CD  and doses (7.5 g/day to 10 g twice daily) of these prebiotics have been undertaken in patients with active disease ,57,58,59Exclusive enteral nutrition (EEN), a liquid-only diet that allows no food intake, is considered the gold standard treatment option in pediatric CD. EEN is, however, not considered as a first-line therapy in pediatric UC patients , but verVarious fiber intervention studies have been conducted in adult IBD patients with active disease or during remission. For the studies conducted during remission, a combination of both food- and supplement-based fiber interventions have been used. Of the food-based studies undertaken, Chiba and colleagues conducted a study to determine whether a semi-vegetarian diet (SVD), with a fiber content of 32.4 g/day, played a preventative role against disease relapse in CD patients when compared to an omnivore diet (OD). Remission was maintained in 100% and 92% of the SVD group at 1- and 2-years follow-up, respectively, whereas remission was only achieved in 67% and 25% of the OD group at 1- and 2-years follow-up, respectively. Overall cumulative disease relapse rates were significantly lower in the SVD compared to the OD group . The addPlantago ovata seed (POS) supplement, a fiber supplement known to increase butyrate production, led to similar treatment response rates as mesalamine, a conventional IBD therapy [Fiber supplementation has also been used to help prevent disease relapse in IBD patients. A randomized controlled trial (RCT) in UC patients demonstrated that taking a  therapy . A GBF s therapy . The useThe gut microbiome is an ecosystem residing within the human GI tract that comprises trillions of microorganisms such as bacteria, archaea, fungi and viruses as well as their respective genes and functions . Diet, pAlistipes spp., Bilophila spp. and Bacteroides spp.), whereas it decreased the abundance of Firmicutes considered beneficial to the host such as Roseburia spp., Eubacterium rectale and Ruminococcus bromii [Dietary patterns directly influence the microbiota composition as well as its effects on the host. A study conducted in healthy American volunteers observed that an animal-based diet rich in meats, eggs and cheeses increased the abundance of microorganisms more tolerant to bile acids ; however, associations between DF consumption and the enhancement of these bacteria in the gut are challenging due to substantial heterogeneity between studies [Notably, a systematic review and meta-analysis conducted by So and colleagues  exploreder SCFAs . Several studies .The gut microbiome plays a key role in the maintenance of gut homeostasis, nutrient and drug metabolism ,78, protBifidobacterium spp. has been observed in pediatric IBD patients when compared to healthy controls [Bifidobacterium spp. are known to reduce potential pathobionts and produce anti-inflammatory SCFAs [Bifidobacterium spp., which protect the host against intestinal inflammation, along with the expansion of Proteobacteria, with pro-inflammatory characteristics, are observed in pediatric patients with IBD , Actinobacteria, Ruminococcus gnavus, Parabacteriodes and Lachnospiraceae [Faecalibacterium prausnitzii. Interestingly, this study was one of the only fiber intervention studies in IBD patients that also led to no clinical benefits [n = 4) after receiving a FOS supplement for 3 weeks were demonstrated to have a significant increase in mucosal total bacteria and bifidobacteria [Bifidobacterium longum was observed [Fiber intervention studies in adult IBD patients have also been shown to modulate the composition of the gut microbiota, not just the metabolites they produce. The most consistent fiber-specific alteration in gut microbiota composition has been the expansion of bifidobacteria ,57,59. Opiraceae   or virome (virus) of IBD patients and whether changes in these microorganisms are associated with enhanced clinical outcomes. Utilization of microbiome analysis techniques such as shotgun metagenomic sequencing will provide in-depth data on the influence fiber has on the composition and functional capacity of gut-associated bacteria, viruses and fungi.In summary, the results generated from the small number of studies that have investigated the impact fiber has on the gut microbiome of IBD patients suggest that fiber could be utilized as a microbiome-targeted therapeutic strategy to reduce dysbiosis and enhance clinical outcomes in IBD patients. There are still large gaps in our knowledge on the impact fiber has on the microbiome of children with IBD, what fiber types and doses are the most efficacious and whether fiber interventions can be utilized to beneficially modulate microorganisms other than bacteria, such as fungi and viruses.To the best of our knowledge, all fiber and prebiotic intervention studies in IBD patients have been conducted in adults. Therefore, a major knowledge gap relating to the efficacy of these interventions in a pediatric patient cohort exists. The majority of studies undertaken in adult IBD patients do suggest that fiber and prebiotic interventions are able to relieve GI symptoms, reduce disease activity, increase the length of time in remission and improve QoL. One study was, however, unable to demonstrate any positive outcomes associated with a FOS supplement in CD patients. Interestingly, this was one of the only studies that was unable to show any significant changes in the gut microbiome due to a fiber or prebiotic intervention. Was the lack of clinical benefits observed in this study related to the failure of the FOS supplement to modulate the gut microbiome? This is a question that certainly warrants further investigation. Even though there is some heterogeneity in results between studies in adult IBD patients, further investigation in a pediatric IBD cohort is definitely warranted.Both pediatric and adult IBD patients appear to have dysbiotic gut microbiome profiles when compared to healthy individuals. Therefore, interventions known to beneficially modulate the gut microbiome, i.e., fiber and prebiotics, may help to restore gut homeostasis and positively impact IBD outcomes. It is believed that fiber can dampen down the immune system and strengthen intestinal epithelial barrier function via modulation of the gut microbiome to produce health-promoting metabolites such as SCFAs. Interestingly, several studies have shown that bifidobacteria and the SCFA, butyrate, are inversely associated with markers of disease activity, suggesting certain bacterial taxa and their metabolites may play a protective role in IBD.Unfortunately, some fiber and prebiotic supplements were not well tolerated by the IBD patients included in the studies outlined in this review. This may be due to some IBD patients having concurrent IBS of which various fiber types are known to exacerbate GI symptoms. It is unclear whether pediatric IBD patients would experience similar IBS-related symptoms due to fiber and prebiotic supplementation. This further establishes the need to undertake well-designed fiber and prebiotic intervention studies in the pediatric IBD population.At present, there is an absence of conclusive evidence to either support or discourage the use of fiber- and prebiotic-containing foods or supplements by adult or pediatric IBD patients, either during remission or active disease. Preliminary results in adult IBD patients provide some evidence to suggest that these dietary strategies may enhance outcomes in IBD patients. The true efficacy of fiber and prebiotic interventions does, however, need to be elucidated before these potential therapeutics can be widely recommended to IBD patients. Therefore, large-scale, robustly designed fiber- and prebiotic-specific RCTs are in high demand, particularly in the pediatric population where to date no relevant studies have been conducted.


Resting-state functional connectivity provides novel insight into variations in neural networks associated with addiction to stimulant drugs in individuals with and without a family history of addiction, and both with and without personal drug use. An increased risk for addiction, either because of drug use or genetic/psychosocial vulnerability, is associated with hypoconnectivity in frontostriatal networks, which may weaken goal-directed decision-making. Resilience against addiction development, by contrast, is characterized by hyperconnectivity in two corticostriatal pathways, possibly reflecting compensatory responses in networks associated with regulatory control over habitual behaviors. It is thus conceivable that defying the risk of developing stimulant drug addiction requires increased efforts to control behavior—a hypothesis that may open up new pathways for therapeutic and preventative strategies. Regular drug use can lead to addiction, but not everyone who takes drugs makes this transition. How exactly drugs of abuse interact with individual vulnerability is not fully understood, nor is it clear how individuals defy the risks associated with drugs or addiction vulnerability. We used resting-state functional MRI (fMRI) in 162 participants to characterize risk- and resilience-related changes in corticostriatal functional circuits in individuals exposed to stimulant drugs both with and without clinically diagnosed drug addiction, siblings of addicted individuals, and control volunteers. The likelihood of developing addiction, whether due to familial vulnerability or drug use, was associated with significant hypoconnectivity in orbitofrontal and ventromedial prefrontal cortical-striatal circuits—pathways critically implicated in goal-directed decision-making. By contrast, resilience against a diagnosis of substance use disorder was associated with hyperconnectivity in two networks involving 1) the lateral prefrontal cortex and medial caudate nucleus and 2) the supplementary motor area, superior medial frontal cortex, and putamen—brain circuits respectively implicated in top-down inhibitory control and the regulation of habits. These findings point toward a predisposing vulnerability in the causation of addiction, related to impaired goal-directed actions, as well as countervailing resilience systems implicated in behavioral regulation, and may inform novel strategies for therapeutic and preventative interventions. Diagnostic and Statistical Manual DSM-5  in interaction with drug-related effects are critical for the transition to addiction in at-risk individuals. We deliberately focused on stimulant drugs because of their direct effect on the midbrain dopamine system that modulates corticostriatal function, resulting in their high addiction liability. We collected resting-state brain activity in individuals with familial risk of addiction, of whom half were addicted to stimulant drugs, and the other half were their unaffected biological siblings. We compared these participants with individuals with no family history of addiction, of whom half had a personal history of regular stimulant drug use , while the other half did not. Our specific hypotheses were that an increased vulnerability for addiction would be reflected in functional dysconnectivity in frontostriatal pathways implicated in goal-directed behavior and prefrontal control  and thatGroup characteristics are shown in P = 0.045). As shown in Familial risk of addiction was associated with significantly reduced functional connectivity in frontostriatal pathways between the vmCAU seed with the rostral anterior cingulate cortex (rACC), medial, though mainly lateral, OFC, and medial prefrontal cortex (mPFC). These connections survived cluster-level correction (within the whole brain) and (for extracted scores) post hoc statistical correction using a mixed-effect model  and 2) the vlPUT, the insula and the supramarginal gyrus, but only the latter survived post hoc correction .Stimulant use  was related to hypoconnectivity in two left-lateralized networks associated with the vmCAU or vlPUT seeds B. ComparP = 0.274) while the effect of stimulant use survived , supporting the notion that socioeconomic factors play a critical part in the addiction vulnerability that family members share.The sibling pairs differed significantly from the other two groups in terms of education, income, and age of tobacco use onset —variableP < 0.001), as well as between 2) pdlPUT and several structures, including the central opercular cortex, supplementary motor area (SMA), medial superior frontal cortex, middle cingulate gyrus, and insula cortex . The significant interaction effects related to the vmCAU and the posterior dlPUT pathways, respectively, were right-lateralized and significantly correlated with one another in the entire sample . However, this correlation was only evident in individuals who did not use stimulant drugs , and not in stimulant-using participants . The lack of this relationship in stimulant-using participants  was partly mediated by their pattern of compulsive stimulant drug use, as measured by the obsessive-compulsive drug use scale (OCDUS) , suggesting that 1) compulsive stimulant use disrupted the interplay between these two regulatory networks and 2) that the corticostriatal hyperconnectivity in the “resilient” group contributed to their protection from compulsive drug use. The inclusion of education, income, and age of tobacco onset as covariates in the mixed-effect model did not change the significance of the results .Significant interaction effects were observed for three of the six seeds: vmCAU vlPUT, and pdlPUT . Individ (OCDUS)  , we identified distinct, lateralized abnormalities in functional connectivity strength associated with both increased risk of, and resilience to, developing stimulant addiction. The risk of developing addiction  was associated with significant reduction in functional connectivity (hypoconnectivity) between vmCAU, left OFC, and vmPFC, regions that have been critically implicated in flexible, goal-directed, value-based decision-making . ResilieAs shown in 4043The amygdala is also important for modulating both goal-directed and habitual behavior in addiction, based on several animal-based studies . HoweverImportantly, structures implicated in motivational control over behavior, such as the nucleus accumbens, did not reveal abnormalities in functional connectivity. This is consistent with previous research showing normal activation in the ventral striatum during reward anticipation in stimulant-addicted adults , 49 and We also found that regular use of stimulant drugs was associated with reduced functional connectivity between the vlPUT, insula (both anterior and posterior parts), and the supramarginal gyrus B, a netwHyperconnectivity in two regulatory control pathways in resilient individuals may seem paradoxical as these individuals do not meet the criteria for addiction and typically perform within the normal range. However, hyperconnectivity at rest is not thought to be associated with dysfunction but instead to reflect compensatory efforts to meet increased functional demands –66. ThisOur data suggest that addiction vulnerability is associated with increased demands on regulatory control systems, to which resilient individuals respond with hyperconnectivity. Compromised control is a hallmark of addiction, and this may not be solely reflected in the connectivity strength of the goal-directed and habit system, but by their interactions. Our data suggest that regular stimulant drug use disrupts the coupling between these two regulatory networks, and the degree of this disruption is partly determined by the severity of compulsive drug use, as measured by the OCDUS scale. Conceivably, hyperconnectivity of these two circuitries in the nonaddicted stimulant drug users might prevent their drug use from developing into a compulsive habit.A second “top-down” system exerting inhibitory control over goal-directed actions between the dorsal anterior cingulate and the vlPUT  was alsoExamining functional connectivity within corticostriatal networks across individuals with and without familial risk and stimulant drug use offers a unique opportunity for delineating differences in network function that may underlie vulnerability and resilience to addiction. By including groups in the study that are understudied in addiction, such as individuals with a family history of addiction and recreational drug users, we provide a different perspective on the current addiction literature . Most stThere are, however, several other factors that we have not examined, such as genetic influences, drug use severity, or the concomitant use of other drugs. We therefore want to emphasize that our main aim was not to ascertain the effects of specific drugs on brain connectivity, which has already been the subject of prior work, but to identify the pattern of abnormality associated with drug addiction and addiction vulnerability more generally. We therefore employed a study design in which the regular use of several drugs was restricted to the group that met criteria for addiction and less severe drug use was characteristic of the nonaddicted drug user group. However, all drug-using participants regularly used stimulant drugs, which directly affect the function of dopaminergic striatal pathways.We acknowledge that a major limitation is that relevant behavioral data are not available to endorse our conclusions made about the functioning of the relevant neural circuitries based on our citation of the extensive functional neuroimaging literature that already exists for both healthy individuals and stimulant drug users. Of course, caution should also be used when interpreting these data because task-induced blood oxygenation level-dependent (BOLD) activation and spontaneous BOLD activation during resting-state functional MRI (fMRI) represent different neuronal processes and are therefore not directly comparable .Although our sample size of 162 was reasonable, the group sizes were unbalanced, and there was relatedness between the familiality (F+) but not the control groups (F−). These limitations are largely due to practical reasons of recruitment, but we have statistically controlled for them and did not include these covariates in the main model to avoid overfitting. We also acknowledge the limitation that participants with familial risk were related whereas participants who were using stimulants were not. We statistically accounted for their relationship by using a mixed-effect model in which we considered clustering of siblings within family as a random effect.Overall exposure to drugs differs between the addicted and nonaddicted drug users, as would be expected. It also raises the important question whether nonaddicted users may only be at an earlier stage in the addiction cycle or represent an entirely different phenotype. We argue for the latter, suggesting that these nonaddicted drug users show a number of characteristics that render them less vulnerable to addiction, including less compulsive drug use, later onset of drug use (including stimulant drug use), higher socioeconomic status, and the absence of both familial risk and childhood adversity . More reThe networks we identified using the striatal seeds are strikingly consistent with previously published research using the same seeds in healthy individuals , and, wh77Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR)–diagnosed stimulant-addicted individuals  and in a highly compulsive manner , as reflected by the OCDUS score (mean 24.4 [±9.2]) whereas the nonaddicted users without a family history of addiction did not (mean 1.2 [±1.7]). Exclusion criteria were a lifetime history of a psychiatric, neurological, or neurodevelopmental disorder, traumatic head injury, and stimulant use for medical reasons.A total of 179 participants were recruited for this study (full details described elsewhere) . BrieflyAll participants followed the same protocol, as described elsewhere . They co3 voxels). All scans were screened for abnormal radiological appearance by a specialist in neuroradiology. Neuroimaging data of five participants were unavailable and had to be excluded for 12 owing to poor scanning quality, resulting in a final sample of 162 participants.All participants underwent magnetic resonance brain scans at the Wolfson Brain Imaging Centre, University of Cambridge, United Kingdom, using a Siemens TIM-Trio 3T system with an eight-channel radio frequency head coil array. Participants were instructed to keep their eyes closed, relax, think of nothing particular, and lie still in the scanner during the resting-state fMRI scan. The fMRI data including 261 volumes were acquired with a T2*-weighted echo planar imaging sequence . Whole brain T1-weighted structural images were acquired with a magnetization-prepared rapid acquisition gradient echo sequence . The first six volumes were discarded to ensure longitudinal magnetization reaches a steady state, resulting in 255 volumes for each participant. We applied motion correction, removed nonbrain structures and signals related to 10% background noise, performed intensity normalization with the grand mean = 1,000 and spatial smoothing with a 6-mm full width at half maximum Gaussian Kernel (using FSL’s SUSAN). Head motion was evaluated by framewise displacement (FD) (The resting-state fMRI data were preprocessed using the FMRIB Software Library (FSL)  , 94. Fouent (FD) . The indent (FD) . In thisent (FD) . FinallyThe RSFC estimates were computed using a seed-based approach in this study . In lighP < 0.05)  model as previously described  to asses < 0.05) .The significant mean cluster RSFC-z values  identified in the main and interaction effects from the neuroimaging data were imported into Mplus software  and analafhayes.com/index.html) implemented in SPSS to examine the impact of stimulant-related compulsivity (OCDUS) on the regulatory balance between the identified inhibitory and habitual control RSFC networks. The χ2 or Fisher’s exact tests were used for the analysis of categorical data. All statistical tests were two-tailed, and a significance level was set at 0.05.Demographic and questionnaire data were examined with SPSS  using a two-way analysis of covariance (ANCOVA) model with the two between-subject factors: “familial risk”  and “stimulant use”  . Both we


However, possible adverse effects and their mechanisms are poorly understood. High-level NAM administration can exert negative effects through multiple routes. For example, NAM by itself inhibits poly(ADP-ribose) polymerases (PARPs), which protect genome integrity. Elevation of the NAD+ pool alters cellular energy metabolism. Meanwhile, high-level NAM alters cellular methyl metabolism and affects methylation of DNA and proteins, leading to changes in cellular transcriptome and proteome. Also, methyl metabolites of NAM, namely methylnicotinamide, are predicted to play roles in certain diseases and conditions. In this review, a collective literature search was performed to provide a comprehensive list of possible adverse effects of NAM and to provide understanding of their underlying mechanisms and assessment of the raised safety concerns. Our review assures safety in current usage level of NAM, but also finds potential risks for epigenetic alterations associated with chronic use of NAM at high doses. It also suggests directions of the future studies to ensure safer application of NAM.Nicotinamide (NAM) at doses far above those recommended for vitamins is suggested to be effective against a wide spectrum of diseases and conditions, including neurological dysfunctions, depression and other psychological disorders, and inflammatory diseases. Recent increases in public awareness on possible pro-longevity effects of nicotinamide adenine dinucleotide (NAD Since Elvehjem et al. reported a cure for canine pellagra dogs using nicotinic acid amide (known as nicotinamide) in 1938 , preventSince the early 1940s, NAM and niacin ) have been heavily consumed as food supplements in the USA. Per capita consumption of niacin in the USA has doubled since implementation of mandatory niacin fortification in the early 1940s . Due to +), which plays important roles in metabolic homeostasis, and activities of certain enzymes that play critical roles in health and longevity. SIRT1, for example, is a molecule that plays important roles against age-associated dysfunction as well as in resistance to oxidative stress. Levels of both NAD+ and SIRT1 activity decline with aging. Counter-balancing this change through NAD+ supplementation has been proposed as beneficial for healthy aging in animal and human studies . Comprehensive understanding of the effects of these chemicals and NAM would produce invaluable information regarding a life-long application of these NAD+ precursors.Finally, a number of clinical trials on NAD


Dental pulp tissue exposed to mechanical trauma or cariogenic process results in root canal and/or periapical infections, and conventionally treated with root canal procedures. The more recent regenerative endodontic procedure intends to achieve effective root canal disinfection and adequate pulp–dentin tissue regeneration; however, numerous limitations are reported. Because tooth is composed of vital soft pulp enclosed by the mineralized hard tissue in a highly organized structure, complete pulp–dentin tissue regeneration has been challenging to achieve. In consideration of the limitations and unique dental anatomy, it is important to understand the healing and repair processes through inflammatory-proliferative-remodeling phase transformations of pulp–dentin tissue. Upon cause by infectious and mechanical stimuli, the innate defense mechanism is initiated by resident pulp cells including immune cells through chemical signaling. After the expansion of infection and damage to resident pulp–dentin cells, consequent chemical signaling induces pluripotent mesenchymal stem cells (MSCs) to migrate to the injury site to perform the tissue regeneration process. Additionally, innovative biomaterials are necessary to facilitate the immune response and pulp–dentin tissue regeneration roles of MSCs. This review highlights current approaches of pulp–dentin tissue healing process and suggests potential biomedical perspective of the pulp–dentin tissue regeneration. Dental infection is demonstrated as a bacteria mediated destruction of periapical tissue, including dental pulp, apex, and periodontium, accompanied by pain, swelling, mobility, and abscess formation . Dental To overcome the current unsolved problems of pulp–dentin tissue regeneration, dental tissue engineering has adopted the use of various sources of stem cells, scaffold systems, and growth factors ,27,28. WThis review will discuss the inflammatory response on the pulp–dentin interface, which is essential for the subsequent healing and repair process. Throughout the numerous dental tissue engineering approaches, the pulp–dentin tissue interface is known to be the primary healing process. Depending on the depth of caries or bacterial penetration, the healing interface could be the line of defense and found as multiple loci from the coronal part to the root apex in any area of pulp–dentin tissue.Normal pulp tissue is composed of organized cell layers that proliferate and differentiate to complete the root formation . The pulDuring root dentin development, Hertwig’s epithelial root sheath (HERS) presents as a merged inner- and outer-enamel epithelial structure from the cervical loop of the enamel organ surrounding the root surfaces. The HERS then proliferates towards the distal end and bends at a near 45 degree angle forming an epithelial diaphragm which determines the number, shape, and size of the root . HERS plHowever, after exposure to infection, the pulp–dentin interface of root structures, including radicular pulp, apical papilla, and HERS, show significant histopathologic alterations devoid of cellular components (odontoblasts and MSCs) and misplacement of cementum-like, osteo-like, periodontal ligament-like tissue ,39,40. TThe tooth structure is composed of inner non-mineralized pulp tissue, one directional neurovascular supply, and surrounding mineralized dentin. Due to the dental pulp being confined by mineralized tissue, the initial inflammatory/immunological reaction increases intra-canal pressure, and the pressure extends toward the root apex down the root canal, causing periapical abscess ,41,42. LOdontoblasts—dentin-producing cells—have been shown to sense bacterial pathogens at the pulp–dentin interface and respond to them by releasing proinflammatory cytokines and antibacterial agents such as nitric oxide (NO) ,30,46. NMacrophages serve to phagocytose invading pathogens and can be activated by Th1 and inhibited by Th2 . MacrophA current study reports that inflammatory responses are prerequisite and can stimulate dental tissue repair responses . When thWhile the inflammatory phase of pulp–dentin tissue progresses, the cellular proliferation and differentiation phases are necessary for the wound healing/repair process ,61. DuriStem cells possess the ability of self-renewal and pluripotency resulting in the capacity to differentiate into a variety of cell types . Stem ceMSCs has been studied to perform a major role in tooth growth and repair by responding to biological stimulations and signals . DependiDental infection that progresses and reaches the periapical and periodontal interface by extended pathology as a periodontal abscess can be classified as either marginal periodontitis or apical periodontitis. Both forms of periodontitis lead to the destruction of surrounding dentin, cementum, periodontal ligament (PDL), alveolar bone, and gingival tissue . During Nitric oxide (NO), a short-lived radical and inert gas, reserves a vital function in regulating inflammatory response in wound repair. Innate NO is produced by immune and non-immune cells by nitric oxide synthase (NOS) via L-arginine metabolism. Among the known three isoforms, endothelial NOS (eNOS) and neuronal NOS (nNOS) are constitutively expressed and produce NO at a constant basal level. Inducible NOS (iNOS) is demonstrated using cytokines, growth factors, and inflammatory stimuli on target cells in the early phase of the inflammation and yields much greater levels of NO than the constitutive isoforms of eNOS and nNOS .As shown in the Additionally, NO coordinates key processes for tissue repair at moderate levels including collagen synthesis, cell proliferation, and cellular differentiation . NO deriFurthermore, NO is known to contribute to the immune response and wound healing process by its antibacterial capacity and regulatory effect on immune cell activation and polarization ,101,102.NO plays an important biphasic role in the function of osteoblasts and osteoclasts. Osteoblasts and osteoclasts are the two major cell types responsible for bone formation and resorption, respectively. The effect of NO on osteoblasts in vitro has been reported to be associated with the concentration of NO present in the local bone microenvironment . High NOThe foundation of reliable pulp–dentin tissue regeneration depends on pulp ECM tissue mimicking scaffolds, characterized as bioactive, antibacterial, and anti-inflammatory materials with a low immunogenic response and a high therapeutic drug delivery efficacy . In addiSynthetic scaffold designs provide an enhanced capacity to optimize mechanical strength and molecular delivery for a targeted therapeutic approach as shown in the Among the newly developed synthetic polymer, a NO releasing biomimetic nanomatrix gel was evaluated as a nature mimicking novel PA based scaffold . This sePulp–dentin tissue regeneration is the series of healing progression from an inflammatory response, immune signaling, and cellular interaction accompanying tissue restoration upon infectious exposure. Due to the unique anatomy of the tooth, infectious tissue damage extends toward the periapical and periodontal regions; therefore, cellular communication among the pluripotent pulp stem cells and immune cells is crucial for an appropriate response. Along with cellular signaling, migrating MSCs, such as DPSCs, could proliferate and differentiate into the pulp–dentin tissue-forming cells including neurovascular tissue regrowth as part of pulp–dentin tissue healing response. The tissue-healing phase is regulated by the anti-inflammatory M2 macrophage following the inflammatory phase. In fact, MSCs are associated with the further promotion of anti-inflammatory M2 macrophage polarization. Meanwhile, consequent tissue regeneration would occur with the facilitation of ECM mimicking bioactive scaffolds and mesenchymal cellular potential. Among the numerous biomedical approaches, recent development of the NO releasing biomimetic nanomatrix gel may provide the necessary supportive function for the pulp–dentin tissue microenvironment to regenerate optimal root dentin and pulp vitality. NO possesses a significant effect on inflammation and tissue healing with the antimicrobial, angiogenic, wound healing, and immunomodulatory properties.


Objective: In paramalleolar bypass for critical limb-threatening ischemia (CLTI), excessive skin tension may occur for the closure of surgical wounds around the ankle. Furthermore, these surgical incisions are often proximal to infectious ischemic ulcers. Wound dehiscence caused by skin tension and surgical site infection carries a risk of graft exposure, anastomotic disruption, or graft insufficiency.Patients and Methods: Tension-free wound management was adopted in eight patients who underwent paramalleolar bypass for CLTI. Tension-free closure was adopted for surgical incisions for distal anastomotic site of the paramalleolar bypass, whereas the incisions for saphenous vein harvest were left open. A relief incision was made as needed. The opened incisions were covered with artificial dermis.Results: All surgical incisions and ischemic wounds healed successfully within 1.8 months after bypass. Two postoperative graft stenoses occurred, which were rescued by additional endovascular intervention. Secondary graft patency, wound healing, and limb salvage rates were 100% during an average follow-up period of 30 months.Conclusion: Tension-free wound closure using artificial dermis was effective in selected cases of paramalleolar bypass for CLTI. The reported outcomes of this bypass surgery appear to be acceptable, however, excellent patency rates and limb salvage rate of bypass surgery are veiled by the occurrence of wound complications. In paramalleolar bypass, several incisions are made around the ankle where the skin is hard to extend; for exposure, from the dorsalis pedis artery to the pedal artery or from the posterior tibial artery to the plantar artery; and for harvesting the saphenous vein graft (SVG). Moreover, infectious ischemic ulcers are proximal to these surgical incisions and wound dehiscence caused by skin tension and surgical site infection has a risk of anastomotic disruption, graft thrombosis, and subsequent limb loss. Furthermore, the vein graft to the dorsalis pedis artery usually passes through the subcutaneous route and overrides in front of the tibia at the ankle level, and excessive skin tension induced by the vein graft passage promotes wound dehiscence and graft exposure.Paramalleolar bypass is a useful revascularization technique for treating critical limb-threatening ischemia (CLTI).In this study, we aimed to investigate the clinical outcomes of tension-free surgical wound management in paramalleolar bypass.Tension-free wound management was chosen to close the paramalleolar surgical wounds of distal bypass when excessive skin tension was recognized in order to prevent wound dehiscence. The surgical incision for the distal anastomotic site of the bypass was closed tension-free by interrupted subcutaneous sutures using absorbable threads and interrupted cutaneous sutures using nonabsorbable threads. On the contrary, the incisions for the SVG harvest were left open. When wound tension could not be reduced only by wound opening for the SVG harvest, an appropriate-sized relief incision was made at the suitable site to reduce the tension of the skin incision on the distal anastomosis. The opened incisions were covered with artificial dermis . The technical methods of tension-free wound management in the paramalleolar bypass to the posterior tibial artery and dorsalis pedis artery are presented in From January 2010 to December 2018, 90 patients received distal bypass for CLTI. Among them, tension-free wound management, as described above, was adopted in one female and seven male patients . Comorbidities of hypertension (n=3 patients), diabetes mellitus (n=7), hemodialysis (n=4), a history of coronary artery disease (n=4), and a history of cerebrovascular disease (n=2) were noted in the included patients. The Rutherford system was used to classify the severity of ischemic ulcers. Seven patients had a stage-5 Rutherford and one patient stage-6 Rutherford. The bypass target arteries were the dorsalis pedis artery in five patients and the posterior tibial artery in three patients. The bypass grafts used were reversed SVG in three patients and non-reversed SVG in five. Open wound management with artificial dermis was performed at the SVG harvest incision in seven patients and a relief incision in one patient.Antiplatelet regimens, such as aspirin, cilostazol, or sarprogrelate hydrochloride, were prescribed for all patients throughout the follow-up period. Clinical assessment and duplex ultrasonographic analysis were performed at discharge and every 3 months thereafter. The study endpoints were graft patency, limb salvage, survival, and wound healing. Major amputation was defined as limb loss above the ankle level, and limb salvage was defined as freedom from major amputation.The study was approved by the ethical committee of our institute . Written informed consent was obtained from all patients by comprehensive agreement method.The postoperative course was unremarkable in all patients. Within 1.8 months (1–4 months) after the bypass, all surgical incisions, including the distal anastomotic site, healed without infection or opening . Two of the patients died of cardiac events at 31 and 41 months, respectively, after the bypass. However, patients with CLTI are at a high risk for various wound complications, such as surgical site infection, lymphorrhea, wound dehiscence, graft exposure, and subsequent graft failure.Paramalleolar bypass using SVG is a standard procedure for managing CLTI. The reported patency and limb salvage rates of this bypass are satisfactory. Severe wound complications with wound dehiscence and graft exposure occurred in 12 of them, which led to 4 major amputations and 1 death. Ouriel et al. reviewed the outcomes of 16 patients with exposed SVG. All patients were initially treated conservatively with moist sterile dressings, followed by split-thickness skin graft coverage of the wounds after cleaning. The wounds healed in seven patients, whereas nine patients developed complications of hemorrhage and graft thrombosis. Recent clinical studies have demonstrated that infection-related graft exposures after lower extremity bypass were successfully treated using autologous tissue, such as pedicle muscle flaps. This aggressive management of infected wounds might be effective, but involves increased length of hospitalization and cost.Wengrovitz et al. investigated wound complications in 163 infrainguinal bypasses.Before the start of this clinical study, we encountered two patients with distal anastomotic rupture of the bypass to the dorsalis pedis artery following wound infection and dehiscence. One of them was a 58-year-old female patient with diabetes and stage-5 Rutherford ulcer. The anastomotic disruption with wound dehiscence occurred 3 weeks after popliteal-to-dorsalis pedis artery with non-reversed SVG. The other patient was a 78-year-old woman with diabetes and stage-5 Rutherford ulcer. The anastomotic rupture occurred 2 weeks after popliteal-to-dorsalis pedis artery with non-reversed SVG. Both patent SVGs had to be ligated and major amputation was inevitable in both patients, and we realized the importance of preventing wound dehiscence and decided to begin tension-free wound management. This wound management was adopted for selected patients in whom the skin tension was excessive for primary closure of paramalleolar surgical wounds; patients with several parallel skin incisions around the ankle for exposure of distal anastomotic site and the SVG harvest; patients with skin sclerosis by persistent ischemia or recurrent infection; and patients with inflammatory edema around the ankle. This method might be particularly effective for bypass to the dorsalis pedis artery which lies in the dorsum pedis with poor skin laxity and runs more peripheral than the posterior tibial artery. Robison et al. introduced the ancillary technique (“pie-crusting”) to reduce skin tension in selected patients with pedal edema or difficult wound closure. Multiple 4- to 5-mm stab incisions through the epidermis and dermis were made using a blade scalpel to facilitate wound closure. There were no distal wound problems among 15 patients who received this surgical technique and were considered to be at the greatest risk for wound breakdown.There are a few studies of inventions to relieve skin tension in paramalleolar bypass for preventing dehiscence of distal anastomotic wounds. Mouton et al. reported the surgical method of a proximalized lateral tunnel for the bypass to the dorsalis pedis artery to protect the SVG exposure induced by wound breakdown. In patients in whom artificial dermis is used for unclosed wounds, complete epithelization occurs in 4–8 weeks. Additional skin transplantation is occasionally needed; however, skin transplantation can be performed simultaneously with minor amputation or wound debridement, which are necessary in most patients with CLTI having ischemic ulcers or gangrene.In our tension-free wound management of paramalleolar bypass, an artificial dermis was used to cover the incision made for SVG harvest or the relief incision. Dermal regeneration templates, such as Pelnac or Terdermis, were designed to treat extensive burn injuries. To date, these techniques have been widely applied to manage various acute and chronic wound sites, and several clinical experiences of using these techniques have been reported in the field of plastic surgery.Tension-free management of surgical wound using artificial dermis seems to be effective in selective patients who receive paramalleolar bypass for CLTI.


Acute brain injuries pose a great threat to global health, having significant impact on mortality and disability. Patients with acute brain injury may develop distant organ failure, even if no systemic diseases or infection is present. The severity of non-neurologic organs’ dysfunction depends on the extremity of the insult to the brain. In this comprehensive review we sought to describe the organ-related consequences of acute brain injuries. The clinician should always be aware of the interplay between central nervous system and non-neurological organs, that is constantly present. Cerebral injury is not only a brain disease, but also affects the body as whole, and thus requires holistic therapeutical approach. Acute brain injuries pose a great threat to global health as stroke stands out as the second most common cause of death overall, while traumatic brain injury is the leading cause of death and disability before age of 45 ,2. CerebBrain injury have been associated with an impairment in pituitary secretion for many years. Greater severity of brain damage has been associated with higher risk of pituitary dysfunctions ,5,6,7. PSome kind of pituitary dysfunction has been observed in up to 82% of patients with ischemic stroke  and 47% The pathophysiology of pituitary deficit in brain injury is multifactorial. Direct damage to the pituitary gland, infundibulum or hypothalamus may be a consequence of the head trauma . AnotherAs pituitary deficiency is an emerging problem, a clinician who deals with patients with acute brain injury should be aware of possible signs and symptoms of pituitary deficiency . AlthougAntidiuretic hormone (ADH) is produced by hypothalamic neurons in the supraoptic and paraventricular nuclei and then transported along the axons connecting them to posterior pituitary gland . CerebraHypothyroidism occurs in 10–30% of patients following traumatic brain injury. In traumatic and cerebrovascular brain injury peripheral conversion of tetraiodothyronine (T4) to triiodothyronine (T3) is reduced and thus low levels of T3 and a rise in reverse T3 (rT3) is observed ,29,30. TAdrenal hormone reduction is estimated to occur in 15% of patients with TBI . AdrenalEndocrine manifestations in acute brain injury are summarized in The link between brain and heart has been known since the 20th century, when Harvey Williams Cushing observed correlation between cerebral compression and blood pressure . CardiacThe presumed aetiology of post-brain injury cardiac complications includes a wide variety of possible mechanisms of which some may be of more importance than the others . ThroughThe norepinephrine-induced toxic effect appeared to be the result of cyclic AMP-mediated calcium overload of the cell and a decrease in cardiocyte’s viability . The endCurrently we distinguish two clinical manifestations of brain injury-related cardiac dysfunction: neurogenic stunned myocardium (NSM) and acute stress induced cardiomyopathy . Whether these are different conditions or simply manifestations of the same pathomechanism is still up for debate ,84.Tako-tsubo cardiomyopathy (TTS) also known as apical ballooning syndrome or broken heart syndrome was initially described by Hikaru Sato in the 1990s . It has Neurogenic stunned myocardium (NSM) is defined as cardiac abnormalities that are caused by neurological events such as traumatic brain injury, ischemic stroke or subarachnoid haemorrhage. It can cause electrocardiogram (ECG) abnormalities suggesting ischemia, wall motion dysfunction and raised troponin levels. Unlike myocardial infarction (MI) there is no significant obstruction of coronary vessels, although differentiating those two conditions can be difficult. NSM is very similar to Tako-tsubo cardiomyopathy in clinical presentation and pathophysiology. Both of those conditions are reversible  and likeCardiac dysfunction is exceptionally relevant in patients with acute brain damage as it may result in a reduction of the left ventricular ejection fraction (LVEF). This may lead to hypotension, low cardiac output and decrease in cerebral blood flow (CBF), causing poor cerebral perfusion, further worsening patient’s outcome. Proper personalized haemodynamic management, including implementation of vasopressors, fluid administration and inotropic support, according to Frank-Starling law, should help maintain CBF.It is worth mentioning that patients with baseline cardiovascular disease such as: hypertension, diffuse arteriosclerosis, heart failure or atrial fibrillation are prone to cerebrovascular incidents. Moreover, cardiac events may lead to falls, especially in the elderly, and thus result in traumatic brain injury. Both, predisposing and triggering factors for low CBP will negatively influence the heart and the brain, leading to negative outcome.Neurogenic pulmonary oedema (NPE) is a form of respiratory distress that timewise correlates with an onset of acute brain injury and cannot be explained by either heart failure or fluid overload . NPE canAll of the abovementioned diseases, despite different aetiologies, share some of the key elements for the development of NPE. Brain injuries that cause NPE are often expressed as an acute increase in the intracranial pressure (ICP), followed by decreased cerebral perfusion or a direct damage of brainstem and hypothalamus .Such stress to which CNS is subjected can cause severe dysregulation of catecholamine homeostasis and lead to a massive α-adrenergic activation which is considered to be the key factor in the development of NPE . CatechoNPE manifests as a typical respiratory failure. Patients often exhibit dyspnoea, tachypnoe, cyanosis, produce frothy sputum and the lungs are often bilaterally infiltrated in chest X-ray imaging . Two disIn order to understand the renal response to brain damage, one needs to realize that it does not always result in kidney injury . Most diAnother disruption of electrolyte-water balance in brain injury is hypernatremia (>145 mmol/L) . Many CNCatecholamine surge, as described in the “heart” section of this review, leads to an increased cardiac output and elevated blood pressure. This, naturally, causes renal blood hyperperfusion which results in augmented creatinine clearance . Udy et All of the abovementioned disorders derive solely from CNS injury, while renal function remains intact. However, in some cases, as mentioned in other sections of this review, brain injury induces systemic inflammatory response and may result in pro-inflammatory cytokine storm that damages renal tubular epithelium and microvasculature in a similar way as in sepsis acute kidney injury (AKI) . AdditioThere is a constant interplay between CNS and the immune system in acute brain injury. Leukocyte infiltration of the brain through the blood-brain-barrier (BBB) has been largely documented and can both attenuate and worsen neurological prognosis . HoweverAcute distress that occurs within the CNS, as previously described, often initiates a wide array of neuroendocrine and neurotransmitter disruptions. Excessive HPA axis and sympathetic nervous (SNS) system activation have a significant effect on the spleen as 98% of all splenic innervation is of SNS origin . There hIt becomes clear that increased susceptibility to infection in acute brain injuries take place during immunosuppression phase . Indeed,2-receptor antagonists (H2Ras) and sucralfate, a mucosa-protective agent acting as acid buffer [Clostridium difficile-associated diarrhea contradict its profitability [One of the possible gastrointestinal manifestation of brain injury could be Cushing’s ulcer, also known as stress ulcer. As its prevalence in severely injured patients is high, gastroduodenal complications are of great significance in intensive care unit (ICU) settings ,157,158.d buffer . Historid buffer ,164,165.tability ,167,168.tability ,170. In tability .The interactions between central nervous system (CNS) and gastrointestinal (GI) tract has been observed for years now. The GI is controlled by autonomic nervous system, but it is also affected by HPA axis. The so-called brain-gut axis may be responsible for increased permeability of the ileal and colonic wall. This may result from brain tissue secretion of proinflammatory molecules and thus cause the release of bacteria and toxins from intestinal lumen into circulation . This coWhen dealing with brain injury patient, one usually focuses on the cerebral insult itself. With this review, the authors wanted to emphasize that central nervous system damage may manifest in wide variety of distant organs. It’s vital to understand that critical care pathways used to treat TBI may also influence distant organ dysfunction. For example, osmotic therapy may cause serious abnormalities in water-electrolyte balance , which i