A leaky gut contributes to postural imbalance in male patients with chronic obstructive pulmonary disease.

AIMS: Patients with chronic obstructive pulmonary disease (COPD) frequently exhibit an inability to maintain postural balance. However, the contribution of increased intestinal permeability or leaky gut to the postural imbalance in COPD is not known. METHODS: We measured plasma zonulin, a marker of leaky gut, with relevance to postural balance in male controls (n = 70) and patients with mild (n = 67), moderate (n = 66), and severe (n = 58) COPD. We employed a short physical performance battery to evaluate postural balance in supine, tandem, and semi-tandem positions. We also measured handgrip strength (HGS), gait speed, plasma c-reactive proteins (CRP), and 8-isoprostanes as potential mechanistic connections between postural imbalance and leaky gut. RESULTS: COPD patients demonstrated higher plasma zonulin, CRP, and 8-isoprostanes levels and lower balance, HGS, and gait speed than controls (all p < 0.05). These findings were more robust in patients with moderate and severe than mild COPD. In addition, plasma zonulin exhibited significant potential in diagnosing poor balance, low HGS, and gait speed in COPD patients (all p < 0.05). We also found significant correlations of plasma zonulin with CRP and 8-isoprostanes, providing heightened inflammation and oxidative stress as mechanistic connections between leaky gut and postural imbalance. CONCLUSION: Plasma zonulin may be helpful in evaluating postural imbalance in COPD patients. Repairing intestinal leaks can be a therapeutic target to improve postural control in COPD.

Gut permeability is associated with lower insulin sensitivity in youth with perinatally acquired HIV.

The relationships between alterations in the intestinal barrier, and bacterial translocation with the development of metabolic complications in youth with perinatally acquired HIV (YPHIV) have not been investigated. The PHACS Adolescent Master Protocol enrolled YPHIV across 15 U.S. sites, including Puerto Rico, from 2007 to 2009. For this analysis, we included YPHIV with HIV viral load 1000 c/ml or less, with at least one measurement of homeostatic assessment of insulin resistance (HOMA-IR) or nonhigh density lipoprotein (non-HDLc) between baseline and year 3 and plasma levels of intestinal fatty-acid binding protein (I-FABP), lipopolysaccharide-binding protein (LBP), and zonulin levels at baseline. We fit linear regression models using generalized estimating equations to assess the association of baseline log 10 gut markers with log 10 HOMA-IR and non-HDLc at all timepoints. HOMA-IR or non-HDLc was measured in 237, 189, and 170 PHIV at baseline, Yr2, and Yr3, respectively. At baseline, median age (Q1, Q3) was 12 years (10, 14), CD4 + cell count was 762 cells/µl (574, 984); 90% had HIV RNA less than 400 c/ml. For every 10-fold higher baseline I-FABP, HOMA-IR dropped 0.85-fold at baseline and Yr2. For a 10-fold higher baseline zonulin, there was a 1.35-fold increase in HOMA-IR at baseline, 1.23-fold increase in HOMA-IR at Yr2, and 1.20-fold increase in HOMA-IR at Yr3 in adjusted models. For a 10-fold higher baseline LBP, there was a 1.23-fold increase in HOMA-IR at baseline in the unadjusted model, but this was slightly attenuated in the adjusted model. Zonulin was associated with non-HDLc at baseline, but not for the other time points. Despite viral suppression, intestinal damage may influence downstream insulin sensitivity in YPHIV.

Booster vaccination with a fractional dose of an oral cholera vaccine induces comparable vaccine-specific antibody avidity as a full dose: A randomised clinical trial.

Antibody avidity is an important measure of the quality of vaccine-induced immune responses. Murine and human studies suggest that antibody avidity may be augmented by limiting access to antigen. The primary objective of this study was to evaluate in primed Swedish adults if booster vaccination with fractional doses (1/5th and 1/25th) of a model oral vaccine, the cholera vaccine Dukoral®, results in higher avidity antibody responses compared to boosting with a full vaccine dose. We also evaluated if fractional booster vaccination elicited similar magnitudes of antibody response compared to a full dose, and if the previously observed increase in antibody avidity after booster vaccination 1-2 years later occurred when boosting after a shorter interval. To this end, a randomised, open-label, exploratory Phase-II trial was performed. Swedish adults (n = 44), primed with two full doses of Dukoral®, were randomised into three groups and given a booster dose at either full (n = 14), 1/5th (n = 17) or 1/25th (n = 13) dose four months later. Antibody responses to cholera toxin B-subunit (CTB) were measured in serum and mucosal antibody in lymphocyte secretions (ALS). We found that the 1/5th and 1/25th booster doses had similar abilities as the full dose to induce significantly higher avidity anti-CTB antibody responses in both ALS and serum samples, as compared to after priming vaccination. There was a non-significant trend to lower magnitudes of ALS and serum IgA responses after the 1/5th compared to the full booster dose, and responses after the 1/25th dose were significantly lower. Our findings suggest fractional booster doses of Dukoral® four months after priming result in anti-toxoid mucosal antibody responses with increased antibody avidity compared to after priming vaccinations. ISRCTN registry identifier 11806026.

Antifouling Lipid Membranes over Protein A for Orientation-Controlled Immunosensing in Undiluted Serum and Plasma.

An important advance in biosensor research is the extension and application of laboratory-developed methodologies toward clinical diagnostics, though the propensity toward nonspecific binding of materials in clinically relevant matrices, such as human blood serum and plasma, frequently leads to compromised assays. Several surface chemistries have been developed to minimize nonspecific interactions of proteins and other biological components found within blood and serum samples, though these often exhibit substantially variable outcomes. Herein we report a surface chemistry consisting of a charged-matched supported lipid membrane that has been tailored to form over a gold surface functionalized with protein A. Fine tuning of the interfacial charge of this membrane, along with rational selection of a backfilling self-assembled monolayer, allows for high surface coverage with retention of orientation-controlled capture antibody attachment. We demonstrate using surface-plasmon resonance (SPR) that this highly charged lipid membrane is antifouling, allowing for complete removal of nonspecific human serum and plasma components using only a mild buffer rinse, which we attribute to unique steric interactions with the underlying surface. Furthermore, this surface chemistry is successfully applied for specific detection of IgG and cholera toxin in undiluted human biofluids with negligible sacrifice of SPR signal compared to buffered analysis. This novel lipid membrane interface over protein A may open new avenues for direct biosensing of disease markers within clinical samples.

Real-Time Detection of Markers in Blood.

The real-time selective detection of disease-related markers in blood using biosensors has great potential for use in the early diagnosis of diseases and infections. However, this potential has not been realized thus far due to difficulties in interfacing the sensor with blood and achieving transparent circuits that are essential for detecting of target markers (e.g., protein, ions, etc.) in a complex blood environment. Herein, we demonstrate the real-time detection of a specific protein and ion in blood without a skin incision. Complementary metal-oxide-semiconductor technology was used to fabricate silicon micropillar array (SiMPA) electrodes with a height greater than 600 µm, and the surface of the SiMPA electrodes was functionalized with a self-assembling artificial peptide (SAP) as a receptor for target markers in blood, i.e., cholera toxin (CTX) and mercury(II) ions (Hg). The detection of CTX was investigated in both in vitro (phosphate-buffered saline and human blood serum, HBO model) and in vivo (mouse model) modes via impedance analysis. In the in vivo mode, the SiMPA pierces the skin, comes into contact with the blood system, and creates comprehensive circuits that include all the elements such as electrodes, blood, and receptors. The SiMPA achieves electrically transparent circuits and, thus, can selectively detect CTX in the blood in real time with a high sensitivity of 50 pM and 5 nM in the in vitro and in vivo modes, respectively. Mercury(II) ions can also be detected in both the in vitro and the in vivo modes by changing the SAP. The results illustrate that a robust sensor that can detect a variety of molecular species in the blood system in real time that will be helpful for the early diagnosis of disease and infections.

Muscle and intestinal damage in triathletes.

The aim of the paper was to assess indicators of muscle and intestinal damage in triathletes. The study involved 15 triathletes whose objective for the season was to start in the XTERRA POLAND 2017 event (1,500-m swimming, 36-km cycling, and 10-km mountain running). Before the 14-week preparatory period, the competitors' body composition was measured, aerobic capacity was tested (graded treadmill test) and blood samples were collected to determine markers showing the level of muscle and intestinal damage. Subsequent tests for body composition were carried out before and after the competition. Blood samples for biochemical indicators were collected the day before the competition, after the completed race, and 24 and 48 hours later. A significant decrease in body mass was observed after completing the race (-3.1±1.5%). The mean maximal oxygen uptake level among the studied athletes equalled 4.9±0.4 L·min-1, 58.8±4.5 mL·kg-1·min-1. The significant increase in concentrations of cortisol, c-reactive protein and myoglobin after the competition, significantly correlated with the significant increase in zonulin concentration (post 1h: r = 0.88, p = 0.007, r = 0,79, p = 0.001, r = 0.78, p = 0.001, and post 12h: r = 0.75, p = 0.01, r = 0.71, p = 0.011, r = 0.83, p = 0.02). No significant changes in the concentration of tumour necrosis factor alpha among the examined competitors were noted at following stages of the study. The results of our research showed that in order to monitor overload in the training of triathletes, useful markers reflecting the degree of muscle and intestinal damage include cortisol, testosterone, testosterone to cortisol ratio, c-reactive protein, myoglobin and zonulin. Changes in muscle cell damage markers strongly correlated with changes in zonulin concentration at particular stages of the study. Thus, one can expect that the concentrations of markers depicting the level of muscle cell damage after an intense and long-lasting effort will significantly influence the level of the intestinal barrier.

Plasma Zonulin Levels as a Non-Invasive Biomarker of Intestinal Permeability in Women with Gestational Diabetes Mellitus.

OBJECTIVE: We aimed to compare the levels of plasma zonulin, a non-invasive biomarker of increased intestinal permeability, between pregnant subjects, with and without gestational diabetes mellitus (GDM), at 24⁻28 gestational weeks. The eighty-five consecutive pregnant subjects that presented to our hospital's obstetrics outpatient clinic and were diagnosed with GDM, for the first time by an oral glucose tolerance test (OGTT), formed the GDM group; 90 consecutive subjects that were not diagnosed with GDM by OGTT, formed the control group. The diagnosis of GDM was made by an OGTT performed between the 24th and 28th weeks of gestation, and in compliance with the American Diabetes Association (ADA) criteria. Plasma zonulin levels were measured by the enzyme-linked immunosorbent assay (ELISA) methods. The Plasma zonulin level was significantly higher in the GDM group than the control group (p < 0.001). A correlation analysis showed that plasma zonulin level was positively correlated to body mass index (BMI), creatinine, fasting plasma glucose, baseline, first hour, and two hours glucose levels and the OGTT, hemoglobin A1C (HbA1C), homeostatic model assessment for insulin resistance (HOMA-IR), and alanine aminotransferase (ALT) levels. Our findings suggest that zonulin may be a non-invasive biomarker involved in the pathogenesis of GDM. Further large-scale studies are needed on this subject.

Serum zonulin as a marker of intestinal mucosal barrier function: May not be what it seems.

The protein, zonulin, has emerged as a popular serological marker to assess the integrity of the intestinal mucosal barrier. However, there is limited information on the utility of serum zonulin to indicate gastrointestinal disease and the validity of zonulin detection in widely-used commercial assays. The current study reports differences in zonulin levels across patient groups with gastrointestinal dysfunction compared with healthy individuals, though methodological inconsistencies indicated that actual zonulin protein was not detected by the commercial assays applied. The nature of the assays' detected antigen was investigated using immunoprecipitation followed by mass spectrometric analysis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by protein staining. Top matches of the assays' detected antigen included haptoglobin and complement C3 for the assay manufactured by CUSABIO (Wuhan, China) and complement C3 for the assay manufactured by Immundiagnostik AG (Bensheim, Germany). These findings confirm that current commercial zonulin assays are not detecting the actual protein as prehaptoglobin-2. Until assay methodology is improved, we advise the greater scientific and medical community to exercise caution in considering the measurement of serum zonulin as a marker of mucosal barrier integrity.

Serum zonulin in patients with inflammatory bowel disease: a pilot study.

BACKGROUND: In recent years it has been supposed that impaired intestinal permeability represents an early event preceding the onset of inflammatory bowel disease (IBD). Since zonulin has been proposed as a biomarker of intestinal permeability, we investigated its role in patients with IBD and the correlation between serum and fecal zonulin. METHODS: A total of 118 IBD patients (86 Crohn's disease [CD] and 32 ulcerative colitis [UC]) and 23 healthy controls (HC) were prospectively enrolled. A serum sample was collected for all the subjects included in the study. A stool specimen collected in the same day of blood drawing was available for a subgroup of 33 IBD patients. Serum and fecal zonulin were tested by ELISA. Non-parametric statistical tests were used for data analysis. RESULTS: Serum zonulin concentration was higher in IBD patients compared to HC (34.5 [26.5-43.9] ng/mL vs. 8.6 [6.5-12.0] ng/mL, P<0.001) showing an area under the curve of 0.98 for their discrimination. No difference in serum zonulin concentration was observed between patients with CD and those with UC (P=0.074). An inverse correlation was observed between serum zonulin concentration and disease duration (rs=-0.30, P=0.001); no correlation was observed between serum and fecal zonulin (rs=0.15, P=0.394). CONCLUSIONS: Serum zonulin is highly sensitive for the evaluation of intestinal permeability in IBD patients. There is no correlation between zonulin values in serum and feces.

Noninvasive biomarkers of gut barrier function identify two subtypes of patients suffering from diarrhoea predominant-IBS: a case-control study.

BACKGROUND: Alterations of the small-intestinal permeability (s-IP) might play an essential role in both diarrhoea-predominant IBS (D-IBS) and celiac disease (CD) patients. Our aims were to analyse in D-IBS patients the symptom profile along with the levels of urinary sucrose (Su), lactulose (La), mannitol (Ma), and circulating biomarkers (zonulin, intestinal fatty acid binding protein - I-FABP, and diamine oxidase - DAO) of the gastrointestinal (GI) barrier function. The pro-inflammatory interleukins 6 and 8 (IL-6 and IL-8), the plasma values of lipopolysaccharide (LPS), and Toll-like receptor 4 (TLR-4) were also investigated. Besides, these biomarkers were compared with those in CD and healthy controls (HC). Finally, comparisons were performed between D-IBS patients with [D-IBS(+)] and without [D-IBS(-)] increased s-IP according to normal or altered La/Ma ratio. METHODS: The study included 39 D-IBS patients, 32 CD patients, and 20 HC. GI permeability was assayed by high-performance liquid chromatography determination in the urine of Su and La/Ma ratio. ELISA kits assayed circulating concentrations of zonulin, I-FABP, DAO, IL-6, IL-8, LPS, and TLR-4. The Mann-Whitney or the Kruskal-Wallis with Dunn's post-test was used to assess differences among the groups. RESULTS: As for the La/Ma ratio, %Su, and I-FABP levels, D-IBS patients were significantly different from CD, but not HC. IL-6 levels were significantly higher in CD than HC, whereas IL-8 levels were significantly higher in both D-IBS and CD patients than HC. By opposite, LPS, and TLR-4 concentrations did not differ significantly among the groups. When D-IBS patients were categorised according to normal or altered s-IP, D-IBS(+) patients had %La, %Su, I-FABP, and DAO levels significantly higher than D-IBS(-) ones. The inflammatory parameters and markers of bacterial translocation (namely, IL-6 and LPS) were significantly higher in D-IBS(+) patients than D-IBS(-) ones. CONCLUSIONS: The present study suggests that two distinct D-IBS subtypes could be identified. The investigation of possible s-IP alterations (i.e., considering the La/Ma ratio) might be useful to assess better and categorise this heterogeneous D-IBS population. TRIAL REGISTRATION: NCT01574209 . Registered March 2012. First recruitment started in April 2012.

Gut Permeability Might be Improved by Dietary Fiber in Individuals with Nonalcoholic Fatty Liver Disease (NAFLD) Undergoing Weight Reduction.

(1) Introduction: Zonulin (ZO) has been proposed as a marker of intestinal permeability. Only a few studies have analyzed to date how diet influences the serum concentration of ZO among patients with non-alcoholic fatty liver disease (NAFLD). We performed a six-month dietetic intervention to evaluate the association between fiber intake and ZO concentration in 32 individuals with NAFLD. (2) Methods: Fiber content in the diet was estimated by Food Frequency Questionnaire (FFQ) and by analyzing 72-h nutritional diaries. ZO concentrations in serum were measured before and after the intervention by immunoenzymatic assay (ELISA). Fatty liver was quantified using the Hamaguchi score before and after the dietetic intervention. (3) Results: During the intervention, the dietary fiber intake increased from 19 g/day to the 29 g/day concomitant with an increase in the frequency of fiber consumption. All patients experienced significant (all p < 0.05) improvements in serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGTP) activities. We also detected decreased serum triglycerides (p = 0.036), homeostatic model assessment insulin resistance (HOMA-IR (p = 0.041) and insulin content (p = 0.34), and improvement of fatty liver status according to the Hamaguchi score (p = 0.009). ZO concentration in serum decreased by nearly 90% (7.335 ± 13.492 vs. 0.507 ± 0.762 ng/mL, p = 0.001) and correlated with the amount of dietary fiber intake (p = 0.043) as well as the degree of fatty liver (p = 0.037). (4) Conclusion: Increasing nutritional fiber results in reduced serum ZO levels, reduced liver enzymes and improved hepatic steatosis in patients with NAFLD, possibly by altering intestinal permeability. Increased dietary fiber intake should be recommended in patients with NAFLD.

Increased zonulin is associated with hyperactivity and social dysfunctions in children with attention deficit hyperactivity disorder.

BACKGROUND: In attention deficit hyperactivity disorder (ADHD), deteriorations of brain gut axis has been shown in previous studies. One area where the most important challenges are seen in ADHD is social functioning. Zonulin is a protein found in the intestinal intraepithelial component; it has been shown that the level of zonulin increases when intestinal permeability is impaired. Changes in intestinal function were shown in ADHD. Zonulin has been shown to be associated with social impairment in children with autism spectrum disorder. In this study, it was aimed to evaluate the relationship between the ADHD symptoms and zonulin in children with ADHD. Secondarily relation of zonulin and difficulties in social functioning was examined in these children. METHODS: Forty children diagnosed with ADHD and forty-one healthy children similar age and gender to ADHD group and their mothers were included in the study. Children without any chronic systemic immunological or infectious diseases were included in the case and control group. The ADHD symptoms were scored by the DuPaul ADHD scale and the social functioning of the children was assessed by the Social Responsiveness Scale (SRS). Serum zonulin levels were analyzed by enzyme-linked immunosorbent assay. RESULTS: Children with ADHD had higher serum zonulin levels and were more impaired in social functioning compared to controls. The level of zonulin was independently predicted with hyperactivity symptoms and SRS scores in regression analysis. CONCLUSION: In this sample of children with ADHD, elevated zonulin levels were associated with increased symptoms of hyperactivity and impairment of social functioning.

Increased jejunal permeability in human obesity is revealed by a lipid challenge and is linked to inflammation and type 2 diabetes.

Obesity and its metabolic complications are characterized by subclinical systemic and tissue inflammation. In rodent models of obesity, inflammation and metabolic impairments are linked with intestinal barrier damage. However, whether intestinal permeability is altered in human obesity remains to be investigated. In a cohort of 122 severely obese and non-obese patients, we analyzed intestinal barrier function combining in vivo and ex vivo investigations. We found tight junction impairments in the jejunal epithelium of obese patients, evidenced by a reduction of occludin and tricellulin. Serum levels of zonulin and LPS binding protein, two markers usually associated with intestinal barrier alterations, were also increased in obese patients. Intestinal permeability per se was assessed in vivo by quantification of urinary lactitol/mannitol (L/M) and measured directly ex vivo on jejunal samples in Ussing chambers. In the fasting condition, L/M ratio and jejunal permeability were not significantly different between obese and non-obese patients, but high jejunal permeability to small molecules (0.4 kDa) was associated with systemic inflammation within the obese cohort. Altogether, these results suggest that intestinal barrier function is subtly compromised in obese patients. We thus tested whether this barrier impairment could be exacerbated by dietary lipids. To this end, we challenged jejunal samples with lipid micelles and showed that a single exposure increased permeability to macromolecules (4 kDa). Jejunal permeability after the lipid load was two-fold higher in obese patients compared to non-obese controls and correlated with systemic and intestinal inflammation. Moreover, lipid-induced permeability was an explicative variable of type 2 diabetes. In conclusion, intestinal barrier defects are present in human severe obesity and exacerbated by a lipid challenge. This paves the way to the development of novel therapeutic approaches to modulate intestinal barrier function or personalize nutrition therapy to decrease lipid-induced jejunal leakage in metabolic diseases. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Maternal Soluble Fiber Diet during Pregnancy Changes the Intestinal Microbiota, Improves Growth Performance, and Reduces Intestinal Permeability in Piglets.

Increasing evidence suggests that maternal diet during pregnancy modifies an offspring's microbiota composition and intestinal development in a long-term manner. However, the effects of maternal soluble fiber diet during pregnancy on growth traits and the developing intestine are still underexplored. Sows were allocated to either a control or 2.0% pregelatinized waxy maize starch plus guar gum (SF) dietary treatment during gestation. Growth performance, diarrhea incidence, gut microbiota composition and metabolism, and gut permeability and inflammation status of 14-day-old suckling piglets were analyzed. The maternal SF diet improved the growth rate and decreased the incidence of diarrhea in the piglets. Next-generation sequencing analysis revealed that the intestinal microbiota composition was altered by a maternal SF diet. The fecal and plasma levels of acetate and butyrate were also increased. Furthermore, a maternal SF diet reduced the levels of plasma zonulin and fecal lipocalin-2 but increased the plasma concentrations of interleukin 10 (IL-10) and transforming growth factor ß (TGF-ß). Additionally, the increased relative abundances of Lactobacillus spp. in SF piglets were positively correlated with growth rate, while the decreased abundances of Bilophila spp. were positively correlated with fecal lipocalin-2 levels. Our data reveal that a maternal SF diet during pregnancy has remarkable effects on an offspring's growth traits and intestinal permeability and inflammation, perhaps by modulating the composition and metabolism of gut microbiota.IMPORTANCE Although the direct effects of dietary soluble fiber on gut microbiota have been extensively studied, the more indirect effects of maternal nutrition solely during pregnancy on the development of the offspring's intestine are until now largely unexplored. Our data show that a maternal soluble fiber diet during pregnancy is independently associated with changes in the intestinal microbiota composition and metabolism of suckling piglets. These findings have direct implications for refining dietary recommendations in pregnancy. Moreover, a maternal soluble fiber diet reduces intestinal permeability and prevents intestinal inflammation and an excessive systemic immune response of suckling piglets. Therefore, the suckling piglets' resistance to disease was enhanced, diarrhea was reduced, and weight gain was raised. Additionally, the changes in gut microbiota in response to a maternal soluble fiber diet may also be directly correlated with the offspring's growth and gut development.

Gut microbiota, dietary intakes and intestinal permeability reflected by serum zonulin in women.

PURPOSE: Increased gut permeability causes the trespass of antigens into the blood stream which leads to inflammation. Gut permeability reflected by serum zonulin and diversity of the gut microbiome were investigated in this cross-sectional study involving female study participants with different activity and BMI levels. METHODS: 102 women were included (BMI range 13.24-46.89 kg m-2): Anorexia nervosa patients (n = 17), athletes (n = 20), normal weight (n = 25), overweight (n = 21) and obese women (n = 19). DNA was extracted from stool samples and subjected to 16S rRNA gene analysis (V1-V2). Quantitative Insights Into Microbial Ecology (QIIME) was used to analyze data. Zonulin was measured with ELISA. Nutrient intake was assessed by repeated 24-h dietary recalls. We used the median of serum zonulin concentration to divide our participants into a "high-zonulin" (> 53.64 ng/ml) and "low-zonulin" (< 53.64 ng/ml) group. RESULTS: The alpha-diversity (Shannon Index, Simpson Index, equitability) and beta-diversity (unweighted and weighted UniFrac distances) of the gut microbiome were not significantly different between the groups. Zonulin concentrations correlated significantly with total calorie-, protein-, carbohydrate-, sodium- and vitamin B12 intake. Linear discriminant analysis effect size (LEfSe) identified Ruminococcaceae (LDA = 4.163, p = 0.003) and Faecalibacterium (LDA = 4.151, p = 0.0002) as significantly more abundant in the low zonulin group. CONCLUSION: Butyrate-producing gut bacteria such as Faecalibacteria could decrease gut permeability and lower inflammation. The diversity of the gut microbiota in women does not seem to be correlated with the serum zonulin concentration. Further interventional studies are needed to investigate gut mucosal permeability and the gut microbiome in the context of dietary factors.

Are self-reported gastrointestinal symptoms among older adults associated with increased intestinal permeability and psychological distress?

BACKGROUND: Despite the substantial number of older adults suffering from gastrointestinal (GI) symptoms little is known regarding the character of these complaints and whether they are associated with an altered intestinal barrier function and psychological distress. Our aim was to explore the relationship between self-reported gut health, intestinal permeability and psychological distress among older adults. METHODS: Three study populations were included: 1) older adults with GI symptoms (n = 24), 2) a group of older adults representing the general elderly population in Sweden (n = 22) and 3) senior orienteering athletes as a potential model of healthy ageing (n = 27). Questionnaire data on gut-health, psychological distress and level of physical activity were collected. Intestinal permeability was measured by quantifying zonulin in plasma. The level of systemic and local inflammation was monitored by measuring C-reactive protein (CRP), hydrogen peroxide in plasma and calprotectin in stool samples. The relationship between biomarkers and questionnaire data in the different study populations was illustrated using a Principal Component Analysis (PCA). RESULTS: Older adults with GI symptoms displayed significantly higher levels of both zonulin and psychological distress than both general older adults and senior orienteering athletes. The PCA analysis revealed a separation between senior orienteering athletes and older adults with GI symptoms and showed an association between GI symptoms, psychological distress and zonulin. CONCLUSIONS: Older adults with GI symptoms express increased plasma levels of zonulin, which might reflect an augmented intestinal permeability. In addition, this group suffer from higher psychological distress compared to general older adults and senior orienteering athletes. This relationship was further confirmed by a PCA plot, which illustrated an association between GI symptoms, psychological distress and intestinal permeability.

Zonulin level, a marker of intestinal permeability, is increased in association with liver enzymes in young adolescents.

BACKGROUND: Zonulin is acknowledged as the only physiological mediator established to reversibly regulate intestinal permeability through modulation of intercellular tight junctions. We aimed to determine whether there are differences in zonulin levels between 74 subjects with overweight or obesity and 76 with normal-weight and to assess correlations of circulating zonulin levels with anthropometric measures and obesity-related biomarkers. METHODS: We assessed anthropometric and laboratory measures, including body mass index (BMI) z-score, blood pressure, liver enzymes, lipid profiles, and insulin resistance. Serum zonulin levels were measured using an enzyme-linked immunosorbent assay. RESULTS: The mean age of the participants was 12.8 ±â€¯1.5 years. Circulating serum zonulin levels were significantly increased in subjects with overweight/obesity compared with those of normal-weight (P = 0.03). Zonulin levels were significantly and positively associated with BMI z-score, alanine aminotransferase levels, triglyceride, fasting insulin, and insulin resistance as indicated by the homeostatic model assessment of insulin resistance (HOMA-IR) (all P < 0.05). In multivariate linear regression analysis, alanine aminotransferase was significantly and positively associated with circulating zonulin levels in adolescents with overweight or obesity (P < 0.01) after controlling for the effect of potential confounding factors. BMI z-score tended to be positively associated with serum zonulin levels in this subgroup analysis (P = 0.06). CONCLUSIONS: Serum zonulin is a biomarker associated with hepatic metabolic disturbances in young adolescents with overweight or obesity. The positive relationship suggests a potentially relevant pathophysiological mechanism linking zonulin to hepatic metabolism in this age group of young adolescents with overweight or obesity.

Imbalance of gut microbiome and intestinal epithelial barrier dysfunction in patients with high blood pressure.

Recent evidence indicates a link between gut pathology and microbiome with hypertension (HTN) in animal models. However, whether this association exists in humans is unknown. Thus, our objectives in the present study were to test the hypotheses that high blood pressure (BP) patients have distinct gut microbiomes and that gut-epithelial barrier function markers and microbiome composition could predict systolic BP (SBP). Fecal samples, analyzed by shotgun metagenomics, displayed taxonomic and functional changes, including altered butyrate production between patients with high BP and reference subjects. Significant increases in plasma of intestinal fatty acid binding protein (I-FABP), lipopolysaccharide (LPS), and augmented gut-targetting proinflammatory T helper 17 (Th17) cells in high BP patients demonstrated increased intestinal inflammation and permeability. Zonulin, a gut epithelial tight junction protein regulator, was markedly elevated, further supporting gut barrier dysfunction in high BP. Zonulin strongly correlated with SBP (R2 = 0.5301, P<0.0001). Two models predicting SBP were built using stepwise linear regression analysis of microbiome data and circulating markers of gut health, and validated in a separate cohort by prediction of SBP from zonulin in plasma (R2 = 0.4608, P<0.0001). The mouse model of HTN, chronic angiotensin II (Ang II) infusion, was used to confirm the effects of butyrate and gut barrier function on the cardiovascular system and BP. These results support our conclusion that intestinal barrier dysfunction and microbiome function are linked to HTN in humans. They suggest that manipulation of gut microbiome and its barrier functions could be the new therapeutic and diagnostic avenues for HTN.