Discovery of circulating blood biomarkers in patients with and without Modic changes of the lumbar spine: a preliminary analysis.

PURPOSE: The following study aimed to determine the existence of blood biomarkers in symptomatic patients with or without lumbar Modic changes (MC). METHODS: A cross-sectional sub-analyses of a prospective cohort was performed. Fasting blood samples were collected from patients with and without lumbar MC who had undergone spinal fusion or microdiscectomy. An 80-plex panel and CCL5/RANTES were used to assess preoperative plasma cytokine concentrations. Patient demographics and imaging phenotypes were also assessed. RESULTS: Thirty-one subjects were analysed (n = 18 no MC; n = 13 MC). No significant differences were found in age, sex, body mass index, smoking and alcohol history, and surgical procedure (i.e. fusion, decompression) between the two groups (p > 0.05). Several statistically significant blood biomarkers in MC patients were identified, including elevated levels of C-C Motif Chemokine Ligand 5 (CCL5, p = 0.0006), while Macrophage Migration Inhibitory Factor (MIF) was significantly lower (p = 0.009). Additionally, C-X-C Motif Chemokine Ligand 5 (CXCL5, p = 0.052), Pentraxin 3 (PTX3, p = 0.06) and Galectin-3 (Gal-3, p = 0.07) showed potential relevance. Moreover, MC patients exhibited significantly higher levels of disc degeneration (p = 0.0001) and displacement severity (p = 0.020). Based on multivariate analyses and controlling for disc degeneration/displacement, CCL5 (OR 1.02; 95% CI 1.002-1.033; p = 0.028) and MIF (OR 0.60; 95% CI 0.382-0.951; p = 0.030) were independently associated with MC patients. CONCLUSION: This "proof-of-concept" study is the first to identify specific and significantly circulating blood biomarkers associated with symptomatic patients with lumbar MC, independent of disc alterations of degeneration and/or bulges/herniations. Specifically, differences in CCL5 and MIF protein levels were significantly noted in MC patients compared to those without MC.

Gut microbial metabolites in Parkinson's disease: Association with lifestyle, disease characteristics, and treatment status.

There is growing appreciation of the importance of the intestinal microbiota in Parkinson's disease (PD), and one potential mechanism by which the intestinal microbiota can communicate with the brain is via bacteria-derived metabolites. In this study, plasma levels of bacterial-derived metabolites including trimethylamine-N-oxide (TMAO), short chain fatty acids (SCFA), the branched chain fatty acid isovalerate, succinate, and lactate were evaluated in PD subjects (treatment naïve and treated) which were compared to (1) population controls, (2) spousal / household controls (similar lifestyle to PD subjects), and (3) subjects with multiple system atrophy (MSA). Analyses revealed an increase in the TMAO pathway in PD subjects which was independent of medication status, disease characteristics, and lifestyle. Lactic acid was decreased in treated PD subjects, succinic acid positively correlated with disease severity, and the ratio of pro-inflammatory TMAO to the putative anti-inflammatory metabolite butyric acid was significantly higher in PD subjects compared to controls indicating a pro-inflammatory shift in the metabolite profile in PD subjects. Finally, acetic and butyric acid were different between PD and MSA subjects indicating that metabolites may differentiate these synucleinopathies. In summary, (1) TMAO is elevated in PD subjects, a phenomenon independent of disease characteristics, treatment status, and lifestyle and (2) metabolites may differentiate PD and MSA subjects. Additional studies to understand the potential of TMAO and other bacterial metabolites to serve as a biomarker or therapeutic targets are warranted.

Abnormal intestinal milieu in posttraumatic stress disorder is not impacted by treatment that improves symptoms.

Posttraumatic stress disorder (PTSD) is a psychiatric disorder, resulting from exposure to traumatic events. Current recommended first-line interventions for the treatment of PTSD include evidence-based psychotherapies, such as cognitive processing therapy (CPT). Psychotherapies are effective for reducing PTSD symptoms, but approximately two-thirds of veterans continue to meet diagnostic criteria for PTSD after treatment, suggesting there is an incomplete understanding of what factors sustain PTSD. The intestine can influence the brain and this study evaluated intestinal readouts in subjects with PTSD. Serum samples from controls without PTSD (n = 40) from the Duke INTRuST Program were compared with serum samples from veterans with PTSD (n = 40) recruited from the Road Home Program at Rush University Medical Center. Assessments included microbial metabolites, intestinal barrier, and intestinal epithelial cell function. In addition, intestinal readouts were assessed in subjects with PTSD before and after a 3-wk CPT-based intensive treatment program (ITP) to understand if treatment impacts the intestine. Compared with controls, veterans with PTSD had a proinflammatory intestinal environment including lower levels of microbiota-derived metabolites, such as acetic, lactic, and succinic acid, intestinal barrier dysfunction [lipopolysaccharide (LPS) and LPS-binding protein], an increase in HMGB1, and a concurrent increase in the number of intestinal epithelial cell-derived extracellular vesicles. The ITP improved PTSD symptoms but no changes in intestinal outcomes were noted. This study confirms the intestine is abnormal in subjects with PTSD and suggests that effective treatment of PTSD does not alter intestinal readouts. Targeting beneficial changes in the intestine may be an approach to enhance existing PTSD treatments.NEW & NOTEWORTHY This study confirms an abnormal intestinal environment is present in subjects with PTSD. This study adds to what is already known by examining the intestinal barrier and evaluating the relationship between intestinal readouts and PTSD symptoms and is the first to report the impact of PTSD treatment (which improves symptoms) on intestinal readouts. This study suggests that targeting the intestine as an adjunct approach could improve the treatment of PTSD.

Alcohol use disorder as a potential risk factor for COVID-19 severity: A narrative review.

In Dec. 2019-January 2020, a pneumonia illness originating in Wuhan, China, designated as coronavirus disease 2019 (COVID-19) was shown to be caused by a novel RNA coronavirus designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). People with advanced age, male sex, and/or underlying health conditions (obesity, type 2 diabetes, cardiovascular disease, hypertension, chronic kidney disease, and chronic lung disease) are especially vulnerable to severe COVID-19 symptoms and death. These risk factors impact the immune system and are also associated with poor health, chronic illness, and shortened longevity. However, a large percent of patients without these known risk factors also develops severe COVID-19 disease that can result in death. Thus, there must exist risk factors that promote exaggerated inflammatory and immune response to the SARS-CoV-2 virus leading to death. One such risk factor may be alcohol misuse and alcohol use disorder because these can exacerbate viral lung infections like SARS, influenza, and pneumonia. Thus, it is highly plausible that alcohol misuse is a risk factor for either increased infection rate when individuals are exposed to SARS-CoV-2 virus and/or more severe COVID-19 in infected patients. Alcohol use is a well-known risk factor for lung diseases and ARDS in SARS patients. We propose that alcohol has three key pathogenic elements in common with other COVID-19 severity risk factors: namely, inflammatory microbiota dysbiosis, leaky gut, and systemic activation of the NLRP3 inflammasome. We also propose that these three elements represent targets for therapy for severe COVID-19.

Gut-Brain Communication in Parkinson's Disease: Enteroendocrine Regulation by GLP-1.

PURPOSE OF REVIEW: Defective gut-brain communication has recently been proposed as a promoter of neurodegeneration, but mechanisms mediating communication remain elusive. In particular, the Parkinson's disease (PD) phenotype has been associated with both dysbiosis of intestinal microbiota and neuroinflammation. Here, we review recent advances in the PD field that connect these two concepts, providing an explanation based on enteroendocrine signaling from the gut to the brain. RECENT FINDINGS: There have been several recent accounts highlighting the importance of the microbiota-gut-brain axis in PD. The objective of this review is to discuss the role of the neuroendocrine system in gut-brain communication as it relates to PD pathogenesis, as this system has not been comprehensively considered in prior reviews. The incretin hormone glucagon-like peptide 1 (GLP-1) is secreted by enteroendocrine cells of the intestinal epithelium, and there is evidence that it is neuroprotective in animal models and human subjects with PD. Agonists of GLP-1 receptors used in diabetes appear to be useful for preventing neurodegeneration. New tools and models have enabled us to study regulation of GLP-1 secretion by intestinal microbiota, to understand how this process may be defective in PD, and to develop methods for therapeutically modifying disease development or progression using the enteroendocrine system. GLP-1 secretion by enteroendocrine cells may be a key mediator of neuroprotection in PD, and new findings in this field may offer unique insights into PD pathogenesis and therapeutic strategies.

Quantitative analysis of short-chain fatty acids in human plasma and serum by GC-MS.

Short-chain fatty acids (SCFAs) are volatile fatty acids produced by gut microbial fermentation of dietary nondigestible carbohydrates. Acetate, propionate, and butyrate SCFA measures are important to clinical and nutritional studies for their established roles in promoting healthy immune and gut function. Additionally, circulating SCFAs may influence the metabolism and allied function of additional tissues and organs. The accurate quantification of SCFAs in plasma/serum is critical to understanding the biological role of SCFAs. The low concentrations of circulating SCFAs and their volatile nature present challenges for quantitative analysis. Herein, we report a sensitive method for SCFA quantification via extraction with methyl tert-butyl ether after plasma/serum acidification. The organic extract of SCFAs is injected directly with separation and detection using a polar GC column coupled to mass spectrometry. The solvent-to-sample ratio, plasma volume, and amount of HCl needed for SCFA protonation were optimized. Method validation shows good within-day and inter-day repeatability. The limit of detection was 0.3-0.6 µg/mL for acetate and 0.03-0.12 µg/mL for propionate and butyrate. Successful application of this method on clinical plasma and serum samples was demonstrated in six datasets. By simplifying the sample preparation procedure, the present method reduces the risk of contamination, lowers the cost of analysis, increases throughput, and offers the potential for automated sample preparation.

The gut microbiota may be a novel pathogenic mechanism in loosening of orthopedic implants in rats.

Particles released from implants cause inflammatory bone loss, which is a key factor in aseptic loosening, the most common reason for joint replacement failure. With the anticipated increased incidence of total joint replacement in the next decade, implant failure will continue to burden patients. The gut microbiome is increasingly recognized as an important factor in bone physiology, however, its role in implant loosening is currently unknown. We tested the hypothesis that implant loosening is associated with changes in the gut microbiota in a preclinical model. When the particle challenge caused local joint inflammation, decreased peri-implant bone volume, and decreased implant fixation, the gut microbiota was affected. When the particle challenge did not cause this triad of local effects, the gut microbiota was not affected. Our results suggest that cross-talk between these compartments is a previously unrecognized mechanism of failure following total joint replacement.

Chronic stress-induced gut dysfunction exacerbates Parkinson's disease phenotype and pathology in a rotenone-induced mouse model of Parkinson's disease.

Recent evidence provides support for involvement of the microbiota-gut-brain axis in Parkinson's disease (PD) pathogenesis. We propose that a pro-inflammatory intestinal milieu, due to intestinal hyper-permeability and/or microbial dysbiosis, initiates or exacerbates PD pathogenesis. One factor that can cause intestinal hyper-permeability and dysbiosis is chronic stress which has been shown to accelerate neuronal degeneration and motor deficits in Parkinsonism rodent models. We hypothesized that stress-induced intestinal barrier dysfunction and microbial dysbiosis lead to a pro-inflammatory milieu that exacerbates the PD phenotype in the low-dose oral rotenone PD mice model. To test this hypothesis, mice received unpredictable restraint stress (RS) for 12 weeks, and during the last six weeks mice also received a daily administration of low-dose rotenone (10 mg/kg/day) orally. The initial six weeks of RS caused significantly higher urinary cortisol, intestinal hyperpermeability, and decreased abundance of putative "anti-inflammatory" bacteria (Lactobacillus) compared to non-stressed mice. Rotenone alone (i.e., without RS) disrupted the colonic expression of the tight junction protein ZO-1, increased oxidative stress (N-tyrosine), increased myenteric plexus enteric glial cell GFAP expression and increased α-synuclein (α-syn) protein levels in the colon compared to controls. Restraint stress exacerbated these rotenone-induced changes. Specifically, RS potentiated rotenone-induced effects in the colon including: 1) intestinal hyper-permeability, 2) disruption of tight junction proteins (ZO-1, Occludin, Claudin1), 3) oxidative stress (N-tyrosine), 4) inflammation in glial cells (GFAP + enteric glia cells), 5) α-syn, 6) increased relative abundance of fecal Akkermansia (mucin-degrading Gram-negative bacteria), and 7) endotoxemia. In addition, RS promoted a number of rotenone-induced effects in the brain including: 1) reduced number of resting microglia and a higher number of dystrophic/phagocytic microglia as well as (FJ-C+) dying cells in the substantia nigra (SN), 2) increased lipopolysaccharide (LPS) reactivity in the SN, and 3) reduced dopamine (DA) and DA metabolites (DOPAC, HVA) in the striatum compared to control mice. Our findings support a model in which chronic stress-induced, gut-derived, pro-inflammatory milieu exacerbates the PD phenotype via a dysfunctional microbiota-gut-brain axis.

Role of TLR4 in the gut-brain axis in Parkinson's disease: a translational study from men to mice.

OBJECTIVE: Recent evidence suggesting an important role of gut-derived inflammation in brain disorders has opened up new directions to explore the possible role of the gut-brain axis in neurodegenerative diseases. Given the prominence of dysbiosis and colonic dysfunction in patients with Parkinson's disease (PD), we propose that toll-like receptor 4 (TLR4)-mediated intestinal dysfunction could contribute to intestinal and central inflammation in PD-related neurodegeneration. DESIGN: To test this hypothesis we performed studies in both human tissue and a murine model of PD. Inflammation, immune activation and microbiota composition were measured in colonic samples from subjects with PD and healthy controls subjects and rotenone or vehicle-treated mice. To further assess the role of the TLR4 signalling in PD-induced neuroinflammation, we used TLR4-knockout (KO) mice in conjunction with oral rotenone administration to model PD. RESULTS: Patients with PD have intestinal barrier disruption, enhanced markers of microbial translocation and higher pro-inflammatory gene profiles in the colonic biopsy samples compared with controls. In this regard, we found increased expression of the bacterial endotoxin-specific ligand TLR4, CD3+ T cells, cytokine expression in colonic biopsies, dysbiosis characterised by a decrease abundance of SCFA-producing colonic bacteria in subjects with PD. Rotenone treatment in TLR4-KO mice revealed less intestinal inflammation, intestinal and motor dysfunction, neuroinflammation and neurodegeneration, relative to rotenone-treated wild-type animals despite the presence of dysbiotic microbiota in TLR4-KO mice. CONCLUSION: Taken together, these studies suggest that TLR4-mediated inflammation plays an important role in intestinal and/or brain inflammation, which may be one of the key factors leading to neurodegeneration in PD.

Alcohol Effects on Colon Epithelium are Time-Dependent.

BACKGROUND: Alcohol intake increases the risk of developing colon cancer. Circadian disruption promotes alcohol's effect on colon carcinogenesis through unknown mechanisms. Alcohol's metabolites induce DNA damage, an early step in carcinogenesis. We assessed the effect of time of alcohol consumption on markers of tissue damage in the colonic epithelium. METHODS: Mice were treated by alcohol or phosphate-buffered saline (PBS), at 4-hour intervals for 3 days, and their colons were analyzed for (i) proliferation (Ki67) and antiapoptosis (Bcl-2) markers, (ii) DNA damage (γ-H2AX), and (iii) the major acetaldehyde (AcH)-DNA adduct, N2 -ethylidene-dG. To model circadian disruption, mice were shifted once weekly for 12 h and then were sacrificed at 4-hour intervals. Samples of mice with a dysfunctional molecular clock were analyzed. The dynamics of DNA damage repair from AcH treatment as well as role of xeroderma pigmentosum, complementation group A (XPA) in their repair were studied in vitro. RESULTS: Proliferation and survival of colonic epithelium have daily rhythmicity. Alcohol induced colonic epithelium proliferation in a time-dependent manner, with a stronger effect during the light/rest period. Alcohol-associated DNA damage also occurred more when alcohol was given at light. Levels of DNA adduct did not vary by time, suggesting rather lower repair efficiency during the light versus dark. XPA gene expression, a key excision repair gene, was time-dependent, peaking at the beginning of the dark. XPA knockout colon epithelial cells were inefficient in repair of the DNA damage induced by alcohol's metabolite. CONCLUSIONS: Time of day of alcohol intake may be an important determinant of colon tissue damage and carcinogenicity.

Diurnal variations in intestinal barrier integrity and liver pathology in mice: implications for alcohol binge.

Recent studies suggest that circadian rhythms regulate intestinal barrier integrity, but it is not clear whether there are daily variations in barrier integrity. This study investigated daily variations in intestinal barrier integrity, including whether there are differences in alcohol-induced intestinal barrier dysfunction after an alcohol binge at different times of day and whether this is associated with concurrent liver injury. C57BL6/J male mice were fed a standard chow diet, an alcohol-containing liquid diet, or an alcohol control diet for 4 wk. During week 5 (i.e., on days 43-45), mice received three once-daily gavages of alcohol (6 g/kg) or the control (phosphate-buffered saline) at the same time each day. Immediately after the binge on the second day, intestinal permeability was assessed. Four hours after the third and final binge, mice were euthanized and tissue samples collected. The results demonstrated diet-specific and outcome-specific effects of time, alcohol, and/or time by alcohol interaction. Specifically, the alcohol binge robustly influenced markers of intestinal barrier integrity, and liver markers were robustly influenced by time of day. Only intestinal permeability (i.e., sucralose) demonstrated a significant effect of time and also showed a binge by time interaction, suggesting that the time of the alcohol binge influences colonic permeability. NEW & NOTEWORTHY This study investigated daily variations in intestinal barrier integrity, including whether there are differences in alcohol-induced intestinal barrier dysfunction after an alcohol binge at different times of day and whether this is associated with concurrent liver injury. We conclude that 1) alcohol binge significantly impacted markers of intestinal permeability, 2) time of day significantly affected liver outcomes, and 3) the time of day influenced colonic permeability.

Circadian Mechanisms in Alcohol Use Disorder and Tissue Injury.

Heavy use of alcohol can lead to addictive behaviors and to eventual alcohol-related tissue damage. While increased consumption of alcohol has been attributed to various factors including level of alcohol exposure and environmental factors such as stress, data from behavioral scientists and physiological researchers are revealing roles for the circadian rhythm in mediating the development of behaviors associated with alcohol use disorder as well as the tissue damage that drives physiological disease. In this work, we compile recent work on the complex mutually influential relationship that exists between the core circadian rhythm and the pharmacodynamics of alcohol. As we do so, we highlight implications of the relationship between alcohol and common circadian mechanisms of effected organs on alcohol consumption, metabolism, toxicity, and pathology.

CREB Protein Mediates Alcohol-Induced Circadian Disruption and Intestinal Permeability.

BACKGROUND: Alcoholic liver disease (ALD) is commonly associated with intestinal permeability. An unanswered question is why only a subset of heavy alcohol drinkers develop endotoxemia. Recent studies suggest that circadian disruption is the susceptibility factor for alcohol-induced gut leakiness to endotoxins. The circadian protein PER2 is increased after exposure to alcohol and siRNA knockdown of PER2 in vitro blocks alcohol-induced intestinal barrier dysfunction. We have shown that blocking CYP2E1 (i.e., important for alcohol metabolism) with siRNA inhibits the alcohol-induced increase in PER2 and suggesting that oxidative stress may mediate alcohol-induced increase in PER2 in intestinal epithelial cells. The aim of this study was to elucidate whether a mechanism incited by alcohol-derived oxidative stress mediates the transcriptional induction of PER2 and subsequent intestinal hyperpermeability. METHODS: Caco-2 cells were exposed to 0.2% alcohol with or without pretreatment with modulators of oxidative stress or PKA activity. Permeability of the Caco-2 monolayer was assessed by transepithelial electrical resistance. Protein expression was measured by Western blot and mRNA with real-time polymerase chain reaction. Wild-type C57BL/6J mice were fed with alcohol diet (29% of total calories, 4.5% v/v) for 8 weeks. Western blot was used to analyze PER2 expression in mouse proximal colon tissue. RESULTS: Alcohol increased oxidative stress, caused Caco-2 cell monolayer dysfunction, and increased levels of the circadian clock proteins PER2 and CLOCK. These effects were mitigated by pretreatment of Caco-2 cells with an antioxidant scavenger. Alcohol-derived oxidative stress activated cAMP response element-binding (CREB) via the PKA pathway and increased PER2 mRNA and protein. Inhibiting CREB prevented the increase in PER2 and Caco-2 cell monolayer hyperpermeability. CONCLUSIONS: Taken together, these data suggest that strategies to reduce alcohol-induced oxidative stress may alleviate alcohol-mediated circadian disruption and intestinal leakiness, critical drivers of ALD.

Alcohol Injury Damages Intestinal Stem Cells.

BACKGROUND: Alcohol consumption is associated with intestinal injury including intestinal leakiness and the risk of developing progressive gastrointestinal cancer. Alcoholics have disruption of intestinal barrier dysfunction that persists weeks after stopping alcohol intake, and this occurs in spite of the fact that intestinal epithelial cells turn over every 3 to 5 days. The renewal and functional regulation of the intestinal epithelium largely relies on intestinal stem cells (ISCs). Chronic inflammation and tissue damage in the intestine can injure stem cells including accumulation of mutations that may result in ISC dysfunction and transformation. ISCs are a key element in intestinal function and pathology; however, very little is known about the effects of alcohol on ISCs. We hypothesize that dysregulation of ISCs is one mechanism by which alcohol induces long-lasting intestinal damage. METHODS: In Vivo: Small intestinal samples from alcohol- and control-fed mice were assessed for ISC markers (Lgr5 and Bmi1) and the changes of the ß-catenin signaling using immunofluorescent microscopy, Western blotting, and RT-PCR. Ex Vivo: Organoids were generated from small intestine tissue and subsequently exposed to alcohol and analyzed for ISC markers, ß-catenin signaling. RESULTS: Chronic alcohol consumption significantly decreased the expression of stem cell markers, Bmi1 in the small intestine of the alcohol-fed mice and also resulted in dysregulation of the ß-catenin signaling-an essential regulator of its target gene Lgr5 and ISC function. Exposure of small intestine-derived organoids to 0.2% alcohol significantly reduced the growth of the organoids, including budding, and total surface area of the organoid cultures. Alcohol also significantly decreased the expression of Lgr5, p-ß-catenin (ser552), and Bmi1 in the organoid model. CONCLUSIONS: Both chronic alcohol feeding and acute exposure of alcohol resulted in ISC dysregulation which might be one mechanism for alcohol-induced long-lasting intestinal damage.

Alcohol Feeding in Mice Promotes Colonic Hyperpermeability and Changes in Colonic Organoid Stem Cell Fate.

BACKGROUND: Alcohol increases intestinal permeability to proinflammatory microbial products that promote liver disease, even after a period of sobriety. We sought to test the hypothesis that alcohol affects intestinal stem cells using an in vivo model and ex vivo organoids generated from jejunum and colon from mice fed chronic alcohol. METHODS: Mice were fed a control or an alcohol diet. Intestinal permeability, liver steatosis-inflammation, and stool short-chain fatty acids (SCFAs) were measured. Jejunum and colonic organoids and tissue were stained for stem cell, cell lineage, and apical junction markers with assessment of mRNA by PCR and RNA-seq. ChIP-PCR analysis was carried out for Notch1 using an antibody specific for acetylated histone 3. RESULTS: Alcohol-fed mice exhibited colonic (but not small intestinal) hyperpermeability, steatohepatitis, and decreased butyrate/total SCFA ratio in stool. Stem cell, cell lineage, and apical junction marker staining in tissue or organoids from jejunum tissue were not impacted by alcohol. Only chromogranin A (Chga) was increased in jejunum organoids by qPCR. However, colonic tissue and organoid staining exhibited an alcohol-induced significant decrease in cytokeratin 20+  (Krt20+) absorptive lineage enterocytes, a decrease in occludin and E-cadherin apical junction proteins, an increase in Chga, and an increase in the Lgr5 stem cell marker. qPCR revealed an alcohol-induced decrease in colonic organoid and tissue Notch1, Hes1, and Krt20 and increased Chga, supporting an alteration in stem cell fate due to decreased Notch1 expression. Colonic tissue ChIP-PCR revealed alcohol feeding suppressed Notch1 mRNA expression (via deacetylation of histone H3) and decreased Notch1 tissue staining. CONCLUSIONS: Data support a model for alcohol-induced colonic hyperpermeability via epigenetic effects on Notch1, and thus Hes1, suppression through a mechanism involving histone H3 deacetylation at the Notch1 locus. This decreased enterocyte and increased enteroendocrine cell colonic stem cell fate and decreased apical junctional proteins leading to hyperpermeability.

Night workers with circadian misalignment are susceptible to alcohol-induced intestinal hyperpermeability with social drinking.

Alcohol-induced intestinal hyperpermeability (AIHP) is a known risk factor for alcoholic liver disease (ALD), but only 20-30% of heavy alcoholics develop AIHP and ALD. The hypothesis of this study is that circadian misalignment would promote AIHP. We studied two groups of healthy subjects on a stable work schedule for 3 mo [day workers (DW) and night workers (NW)]. Subjects underwent two circadian phase assessments with sugar challenge to access intestinal permeability between which they drank 0.5 g/kg alcohol daily for 7 days. Sleep architecture by actigraphy did not differ at baseline or after alcohol between either group. After alcohol, the dim light melatonin onset (DLMO) in the DW group did not change significantly, but in the NW group there was a significant 2-h phase delay. Both the NW and DW groups had no change in small bowel permeability with alcohol, but only in the NW group was there an increase in colonic and whole gut permeability. A lower area under the curve of melatonin inversely correlated with increased colonic permeability. Alcohol also altered peripheral clock gene amplitude of peripheral blood mononuclear cells in CLOCK, BMAL, PER1, CRY1, and CRY2 in both groups, and inflammatory markers lipopolysaccharide-binding protein, LPS, and IL-6 had an elevated mesor at baseline in NW vs. DW and became arrhythmic with alcohol consumption. Together, our data suggest that central circadian misalignment is a previously unappreciated risk factor for AIHP and that night workers may be at increased risk for developing liver injury with alcohol consumption.

A compositional look at the human gastrointestinal microbiome and immune activation parameters in HIV infected subjects.

HIV progression is characterized by immune activation and microbial translocation. One factor that may be contributing to HIV progression could be a dysbiotic microbiome. We therefore hypothesized that the GI mucosal microbiome is altered in HIV patients and this alteration correlates with immune activation in HIV. 121 specimens were collected from 21 HIV positive and 22 control human subjects during colonoscopy. The composition of the lower gastrointestinal tract mucosal and luminal bacterial microbiome was characterized using 16S rDNA pyrosequencing and was correlated to clinical parameters as well as immune activation and circulating bacterial products in HIV patients on ART. The composition of the HIV microbiome was significantly different than that of controls; it was less diverse in the right colon and terminal ileum, and was characterized by loss of bacterial taxa that are typically considered commensals. In HIV samples, there was a gain of some pathogenic bacterial taxa. This is the first report characterizing the terminal ileal and colonic mucosal microbiome in HIV patients with next generation sequencing. Limitations include use of HIV-infected subjects on HAART therapy.

The Circadian Clock Mutation Promotes Intestinal Dysbiosis.

BACKGROUND: Circadian rhythm disruption is a prevalent feature of modern day society that is associated with an increase in pro-inflammatory diseases, and there is a clear need for a better understanding of the mechanism(s) underlying this phenomenon. We have previously demonstrated that both environmental and genetic circadian rhythm disruption causes intestinal hyperpermeability and exacerbates alcohol-induced intestinal hyperpermeability and liver pathology. The intestinal microbiota can influence intestinal barrier integrity and impact immune system function; thus, in this study, we sought to determine whether genetic alteration of the core circadian clock gene, Clock, altered the intestinal microbiota community. METHODS: Male Clock(Δ19) -mutant mice (mice homozygous for a dominant-negative-mutant allele) or littermate wild-type mice were fed 1 of 3 experimental diets: (i) a standard chow diet, (ii) an alcohol-containing diet, or (iii) an alcohol-control diet in which the alcohol calories were replaced with dextrose. Stool microbiota was assessed with 16S ribosomal RNA gene amplicon sequencing. RESULTS: The fecal microbial community of Clock-mutant mice had lower taxonomic diversity, relative to wild-type mice, and the Clock(Δ19) mutation was associated with intestinal dysbiosis when mice were fed either the alcohol-containing or the control diet. We found that alcohol consumption significantly altered the intestinal microbiota in both wild-type and Clock-mutant mice. CONCLUSIONS: Our data support a model by which circadian rhythm disruption by the Clock(Δ19) mutation perturbs normal intestinal microbial communities, and this trend was exacerbated in the context of a secondary dietary intestinal stressor.

Light/Dark Shifting Promotes Alcohol-Induced Colon Carcinogenesis: Possible Role of Intestinal Inflammatory Milieu and Microbiota.

BACKGROUND: Colorectal cancer (CRC) is associated with the modern lifestyle. Chronic alcohol consumption-a frequent habit of majority of modern societies-increases the risk of CRC. Our group showed that chronic alcohol consumption increases polyposis in a mouse mode of CRC. Here we assess the effect of circadian disruption-another modern life style habit-in promoting alcohol-associated CRC. METHOD: TS4Cre × adenomatous polyposis coli (APC)lox468 mice underwent (a) an alcohol-containing diet while maintained on a normal 12 h light:12 h dark cycle; or (b) an alcohol-containing diet in conjunction with circadian disruption by once-weekly 12 h phase reversals of the light:dark (LD) cycle. Mice were sacrificed after eight weeks of full alcohol and/or LD shift to collect intestine samples. Tumor number, size, and histologic grades were compared between animal groups. Mast cell protease 2 (MCP2) and 6 (MCP6) histology score were analyzed and compared. Stool collected at baseline and after four weeks of experimental manipulations was used for microbiota analysis. RESULTS: The combination of alcohol and LD shifting accelerated intestinal polyposis, with a significant increase in polyp size, and caused advanced neoplasia. Consistent with a pathogenic role of stromal tryptase-positive mast cells in colon carcinogenesis, the ratio of mMCP6 (stromal)/mMCP2 (intraepithelial) mast cells increased upon LD shifting. Baseline microbiota was similar between groups, and experimental manipulations resulted in a significant difference in the microbiota composition between groups. CONCLUSIONS: Circadian disruption by Light:dark shifting exacerbates alcohol-induced polyposis and CRC. Effect of circadian disruption could, at least partly, be mediated by promoting a pro-tumorigenic inflammatory milieu via changes in microbiota.

Environmental disruption of circadian rhythm predisposes mice to osteoarthritis-like changes in knee joint.

Circadian rhythm dysfunction is linked to many diseases, yet pathophysiological roles in articular cartilage homeostasis and degenerative joint disease including osteoarthritis (OA) remains to be investigated in vivo. Here, we tested whether environmental or genetic disruption of circadian homeostasis predisposes to OA-like pathological changes. Male mice were examined for circadian locomotor activity upon changes in the light:dark (LD) cycle or genetic disruption of circadian rhythms. Wild-type (WT) mice were maintained on a constant 12 h:12 h LD cycle (12:12 LD) or exposed to weekly 12 h phase shifts. Alternatively, male circadian mutant mice (Clock(Δ19) or Csnk1e(tau) mutants) were compared with age-matched WT littermates that were maintained on a constant 12:12 LD cycle. Disruption of circadian rhythms promoted osteoarthritic changes by suppressing proteoglycan accumulation, upregulating matrix-degrading enzymes and downregulating anabolic mediators in the mouse knee joint. Mechanistically, these effects involved activation of the PKCδ-ERK-RUNX2/NFκB and ß-catenin signaling pathways, stimulation of MMP-13 and ADAMTS-5, as well as suppression of the anabolic mediators SOX9 and TIMP-3 in articular chondrocytes of phase-shifted mice. Genetic disruption of circadian homeostasis does not predispose to OA-like pathological changes in joints. Our results, for the first time, provide compelling in vivo evidence that environmental disruption of circadian rhythms is a risk factor for the development of OA-like pathological changes in the mouse knee joint.