Plasma concentrations of zonulin are elevated in obese men with fatty liver disease

Investigating the Association Between Diet-Induced "Leaky Gut" and the Development of Prediabetes

INTRODUCTION

Chronic consumption of a high-calorie diet compromises the gut microbiota and the integrity of the intestinal wall, which causes translocation of bacterial lipopolysaccharides (LPS) into the blood. This elicits the secretion of pro-inflammatory cytokines, resulting in inflammation. However, how a high-fat high carbohydrate diet affects intestinal permeability and its possible role in the development of prediabetes have not been investigated. This study investigated the effects of HFHC diet-induced prediabetes on gut microbiota and intestinal permeability in male Sprague Dawley rats.

METHODS

The animals were randomly assigned into the non-prediabetic (NPD) and diet-induced prediabetic (PD) groups (n=6) for 20 weeks. Then, the fecal samples were analyzed to measure the gut microbiota level of Firmicutes, Bacteroidetes, and Proteobacteria in both animal groups. Blood glucose, plasma insulin, serum zonulin, plasma LPS, soluble CD14, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and intestinal fatty-acid binding protein (IFABP) concentrations were measured.

RESULTS

The PD group had a reduction in the Firmicutes and an increase in Bacteroidetes and Proteobacteria levels compared to those in the NPD group. Blood glucose, insulin concentration, serum zonulin, and plasma sCD14 concentrations in the PD group increased significantly, while plasma LPS concentrations were similar to the NPD group. Concentrations of plasma TNF-α, IL-6, CRP, and IFABP, an intracellular protein expressed in the intestine, increased in PD compared to the NPD group.

CONCLUSIONS

the study results cumulatively suggest that chronic consumption of the HFHC diet may be associated with the dysregulation of gut microbiota, leading to increased intestinal permeability.

Food, gut barrier dysfunction, and related diseases: A new target for future individualized disease prevention and management

Dysfunction of gut barrier is known as "leaky gut" or increased intestinal permeability. Numerous recent scientific evidences showed the association between gut dysfunction and multiple gastrointestinal tract (GI) and non-GI diseases. Research also demonstrated that food plays a crucial role to cause or remedy gut dysfunction related to diseases. We reviewed recent articles from electronic databases, mainly PubMed. The data were based on animal models, cell models, and human research in vivo and in vitro models. In this comprehensive review, our aim focused on the relationship between dietary factors, intestinal permeability dysfunction, and related diseases. This review synthesizes currently available literature and is discussed in three parts: (a) the mechanism of gut barrier and function, (b) food and dietary supplements that may promote gut health, and food or medication that may alter gut function, and (c) a table that organizes the synthesized information by general mechanisms for diseases related to leaky gut/intestinal permeability and associated dietary influences. With future research, dietary intervention could be a new target for individualized disease prevention and management.

Colonic permeability is increased in non-cirrhotic patients with nonalcoholic fatty liver disease

BACKGROUND AND AIM

Intestinal permeability (IP) plays an important role in the pathophysiology of nonalcoholic fatty liver disease (NAFLD). We assessed site-specific (gastroduodenum, small intestine, colon and whole gut) IP in NAFLD patients and healthy controls (HC) and its association with the degree of hepatic steatosis, hepatic fibrosis and dietary composition in these NAFLD patients.

METHODS

In vivo site-specific IP was analysed with a validated multi-sugar test in NAFLD patients and HC. Furthermore, in NAFLD patients, hepatic steatosis (chemical shift MRI), hepatic fibrosis (transient elastography) and dietary composition (food frequency questionnaire) were assessed.

RESULTS

Fifty-two NAFLD patients and forty-six HC were included in this study. Small intestinal (P <0.001), colonic (P = 0.004) and whole gut (P <0.001) permeability were increased in NAFLD patients compared to HC. Furthermore, colonic permeability (P = 0.029) was significantly higher in NAFLD patients with clinically significant fibrosis compared to those without. Colonic permeability remained positively associated with the presence of clinically significant fibrosis (P = 0.017) after adjustment for age, sex and BMI.

CONCLUSION

Colonic permeability is increased in at least a subset of NAFLD patients compared to HC and is independently associated with clinically significant NAFLD fibrosis.

Increased Intake of Both Caffeine and Non-Caffeine Coffee Components Is Associated with Reduced NAFLD Severity in Subjects with Type 2 Diabetes

Coffee may protect against non-alcoholic fatty liver disease (NAFLD), but the roles of the caffeine and non-caffeine components are unclear. Coffee intake by 156 overweight subjects (87% with Type-2-Diabetes, T2D) was assessed via a questionnaire, with 98 subjects (all T2D) also providing a 24 h urine sample for quantification of coffee metabolites by LC-MS/MS. NAFLD was characterized by the fatty liver index (FLI) and by Fibroscan^® assessment of fibrosis. No associations were found between self-reported coffee intake and NAFLD parameters; however, total urine caffeine metabolites, defined as Σ_caffeine (caffeine + paraxanthine + theophylline), and adjusted for fat-free body mass, were significantly higher for subjects with no liver fibrosis than for those with fibrosis. Total non-caffeine metabolites, defined as Σ_ncm (trigonelline + caffeic acid + p-coumaric acid), showed a significant negative association with the FLI. Multiple regression analyses for overweight/obese T2D subjects (n = 89) showed that both Σ_caffeine and Σ_ncm were negatively associated with the FLI, after adjusting for age, sex, Hb_A1c, ethanol intake and glomerular filtration rate. The theophylline fraction of Σ_caffeine was significantly increased with both fibrosis and the FLI, possibly reflecting elevated CYP2E1 activity-a hallmark of NAFLD worsening. Thus, for overweight/obese T2D patients, higher intake of both caffeine and non-caffeine coffee components is associated with less severe NAFLD. Caffeine metabolites represent novel markers of NAFLD progression.

The association of zonulin-related proteins with prevalent and incident inflammatory bowel disease

Background

Current evidence regarding the association of serum zonulin-related proteins (ZRP) levels with prevalent inflammatory bowel disease (IBD) is contradictory. Moreover, the association with the subsequent risk of incident IBD is still unexplored. This study aimed to investigate the association of serum ZRP levels with both prevalent and incident IBD.

Method

The study included a total of 130 women (51–61 years) from the Women’s Health in Lund Area (WHILA) study, which included 18 prevalent IBD (diagnosed before baseline) and 47 incident IBD diagnosed during the 17 years (median) follow-up and age- and sampling time-matched controls. Serum ZRP was tested in all participants by ELISA.

Results

The serum ZRP levels were significantly higher in prevalent IBD compared to their matched controls (63.2 ng/ml vs 57.0 ng/ml, p = 0.02), however, no evidence of a difference in ZRP levels was found between the women who developed IBD during the follow-up period and their matched controls (61.2 ng/ml vs 59.7 ng/ml, p = 0.34). Using linear mixed models, we found that the association between serum ZRP levels and prevalent IBD (β = 6.2, p = 0.01), remained after adjusting for potential confounders. Conditional logistic regression models showed no evidence of an association between ZRP level and incident IBD (OR 1.03, p = 0.34).

Conclusion

Higher serum ZRP levels were associated with prevalent IBD, but not with incident IBD in our study samples.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02075-y.

A narrative review of the role of gastrointestinal dysbiosis in the pathogenesis of polycystic ovary syndrome

Diet-induced gastrointestinal dysbiosis has been hypothesized to play a significant role in stimulating an increase in gastrointestinal permeability and activating systemic inflammation in women with polycystic ovary syndrome (PCOS). We reviewed the current proof-of-concept studies on the proposed mechanism of dysbiosis in the pathogenesis of PCOS. A literature search was performed to identify articles on changes in the intestinal microbiome (dysbiosis) and increased intestinal mucosal permeability involving lipopolysaccharide (LPS), LPS-binding protein (LPS-BP), and zonulin. We also searched for systematic reviews and meta-analyses that synthesized the results of studies on the therapeutic effects of prebiotics, probiotics, or synbiotics in women with PCOS. Our search was confined to human studies between 2012 and 2021 using the PubMed, Scopus, and Cochrane databases. Thirty-one studies met the inclusion criteria (14 microbiota, 1 LPS, 1 LPS-BP, 1 LPS and LPS-BP, 5 zonulin, 9 systematic reviews). Our analysis revealed that most studies reported reduced alpha diversity and dysbiosis in women with PCOS. Preliminary studies suggest that LPS, LPS-BP, and zonulin may be involved in the pathophysiology of increased intestinal permeability. Treatment of PCOS with prebiotics, probiotics, and synbiotics appears to have a range of beneficial effects on metabolic and biochemical profiles. This review highlights the need for continued research into the pathophysiological mechanisms of dysbiosis and the clinical efficacy of prebiotics, probiotics, and synbiotics in women with PCOS.

Higher bacterial DNAemia can affect the impact of a polyphenol-rich dietary pattern on biomarkers of intestinal permeability and cardiovascular risk in older subjects

PURPOSE

Aging can be characterized by increased systemic low-grade inflammation, altered gut microbiota composition, and increased intestinal permeability (IP). The intake of polyphenol-rich foods is proposed as a promising strategy to positively affect the gut microbiota-immune system-intestinal barrier (IB) axis. In this context, we tested the hypothesis that a PR-dietary intervention would affect the presence of bacterial factors in the bloodstream of older adults.

METHODS

We collected blood samples within a randomized, controlled, crossover intervention trial in which older volunteers (n = 51) received a polyphenol-enriched and a control diet. We quantified the presence of bacterial DNA in blood by qPCR targeting the 16S rRNA gene (16S; bacterial DNAemia). Blood DNA was taxonomically profiled via 16S sequencing.

RESULTS

Higher blood 16S levels were associated with higher BMI and markers of IP, inflammation, and dyslipidemia. PR-intervention did not significantly change bacterial DNAemia in the older population (P = 0.103). Nonetheless, the beneficial changes caused by the polyphenol-enriched diet were greatest in participants with higher bacterial DNAemia, specifically in markers related to IP, inflammation and dyslipidemia, and in fecal bacterial taxa. Finally, we found that the bacterial DNA detected in blood mostly belonged to γ-Proteobacteria, whose abundance significantly decreased after the polyphenol-rich diet in subjects with higher bacterial DNAemia at baseline.

CONCLUSIONS

This study shows that older subjects with higher bacterial DNAemia experienced a beneficial effect from a polyphenol-rich diet. Bacterial DNAemia may be a further relevant marker for the identification of target populations that could benefit more from a protective dietary treatment.

REGISTRATION

This trial was retrospectively registered at www.isrctn.org (ISRCTN10214981) on April 28, 2017.

Physiological mechanisms of unexplained (functional) gastrointestinal disorders

Functional gastrointestinal disorders (FGIDs) encompass a range of complex conditions with similar clinical characteristics and no overt pathology. Recent recognition of sub-clinical pathologies in FGIDs, in conjunction with physiological and biochemical abnormalities including increased intestinal permeability, microbial profile alterations, differences in metabolites and extra-intestinal manifestations of disease, call into question the designation of these conditions as 'functional'. This is despite significant heterogeneity in both symptom profile and specifics of reported physiological abnormalities hampering efforts to determine defined mechanisms that drive onset and chronicity of symptoms. Instead, the literature demonstrates these conditions are disorders of homeostatic imbalance, with disruptions in both host and microbial function and metabolism. This imbalance is also associated with extraintestinal abnormalities including psychological comorbidities and fatigue that may be a consequence of gastrointestinal disruption. Given the exploitation of such abnormalities will be crucial for improved therapeutic selection, an enhanced understanding of the relationship between alterations in function of the gastrointestinal tract and the response of the immune system is of interest in identifying mechanisms that drive FGID onset and chronicity. Considerations for future research should include the role of sex hormones in regulating physiological functions and treatment responses in patients, as well as the importance of high-level phenotyping of clinical, immune, microbial and physiological parameters in study cohorts. There is opportunity to examine the functional contribution of the microbiota and associated metabolites as a source of mechanistic insight and targets for therapeutic modulation.

Prediction of Cardiovascular Risk Using Nonalcoholic Fatty Liver Disease Scoring Systems

This study aimed to determine whether nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for CVD and to identify the most useful NAFLD diagnostic tool for predicting CVD. Data from a total of 23,376 Korean adults without established CVD were analyzed. Cardiovascular risk was calculated using the Framingham Risk Score (FRS) 2008. The presence of NAFLD was defined as moderate-to-severe fatty liver disease diagnosed by ultrasonography. Scores for fatty liver were calculated using four NAFLD scoring systems (Fatty Liver Index, FLI; Hepatic Steatosis Index, HSI; Simple NAFLD Score, SNS; Comprehensive NAFLD Score, CNS), and were compared and analyzed according to cardiovascular risk group. Using the FRS, 67.4% of participants were considered to be at low risk of CVD, 21.5% at intermediate risk, and 11.1% at high risk. As the risk of CVD increased, both the prevalence of NAFLD and the score from each NAFLD scoring system increased significantly (p < 0.001). In the unadjusted analysis, the CNS had the strongest association with high CVD risk; in the adjusted analysis, the FLI score was most strongly associated with high CVD risk. Fatty liver is an important independent risk factor for CVD. Therefore, the available NAFLD scoring systems could be utilized to predict CVD.

Lipopolysaccharide binding protein is associated with CVD risk in older adults

BACKGROUND

Intestinal (i.e., "gut") permeability may be related to cardiovascular disease (CVD) risk, but biomarkers for gut permeability are limited and associations with CVD risk are unknown-particularly among older adults.

AIMS

This cross-sectional study aimed to determine if serum biomarkers related to gut permeability [intestinal fatty acid-binding protein (iFABP)] and bacterial toxin clearing [cluster of differentiation 14 (CD14), lipopolysaccharide binding protein (LBP)] are associated with CVD risk among older adults.

METHODS

Older adults (n = 74, 69.6 ± 6.5-years-old) were stratified by CVD risk category. One-way ANOVAs determined differences in each biomarker by risk category, and associations with risk score were evaluated with Pearson correlations.

RESULTS

LBP (p = 0.007), but not iFABP and CD14, was significantly different between CVD risk categories. Post-hoc tests indicated LBP was higher in moderate risk and high-moderate risk compared to the high risk category (p < 0.005). Evaluation of LBP and individual components in the risk score demonstrated a moderate, negative correlation of LBP with age and systolic blood pressure (r = - 0.335 and r = - 0.297) and a small positive correlation between LBP and total cholesterol and LDL cholesterol (r = 0.204 and r = 0.220).

DISCUSSION/CONCLUSION

Lower risk for CVD was associated with higher circulating concentrations of LBP, lower iFABP, and lower systemic inflammation in older adults. Further, there were small positive relationships between total and LDL cholesterol and circulating levels of LBP. These data suggest LBP may be a key component in reducing CVD risk in older adults.

Changes in serum zonulin in individuals with morbid obesity after weight-loss interventions: a prospective cohort study

BACKGROUND

Zonulin is a biomarker of impaired intestinal permeability, which has been associated with various disorders. The primary aim was to study serum zonulin (s-zonulin) in individuals with morbid obesity before and after a conservative weight loss intervention followed by bariatric surgery. The secondary aims were to explore predictors of s-zonulin, and the associations between the changes of the predictors and changes in s-zonulin, and to compare the associations in the two treatment periods.

METHODS

Individuals with morbid obesity were included. Data before any weight loss interventions, after a 6 months' conservative weight loss intervention, and 6 months after bariatric surgery were used. S-zonulin was measured with an ELISA method from Immundiagnostik AB, Bensheim, Germany. Data were analysed with mixed models.

RESULTS

The mean body mass index was 42.1 kg/m² (SD 3.8) at inclusion and was reduced to 38.7 kg/m² (SD 3.8) and 29.8 kg/m² (SD 3.8) after the conservative treatment and bariatric surgery respectively. S-zonulin was 63 ng/mL (SD 32) at inclusion and was reduced with 19 ng/ml (95% CI 12 to 26, p < 0.001) after conservative treatment and 11 ng/ml (95% CI 0 to 21, p = 0.04) after bariatric surgery. At inclusion, s-zonulin was significantly associated with factors including p-glucose (B = 2.21, 95% CI 1.09 to 3.33, p < 0.001), c-reactive protein (B = 1.02, 95% CI 0.45 to 1.58, p < 0.001) and the intake of proteins (B = 0.23, 95% CI 0.08 to 0.38, p = 0.003) and non-nutritive sweeteners (B = 0.68, 95% CI 0.19 to 1.17, p = 0.007). The reduction in s-zonulin after the conservative weight loss intervention was significantly associated with improvement in diarrhoea (B = 6.6, 95% CI  1.3 to 11.8, p = 0.02), HbA1c (B = 9.7, 95% CI 1.1 to 18.3, p = 0.03), p-glucose (B = 3.5, 95% CI 1.2 to 5.9, p = 0.004) and gamma-GT (B = 0.28, 95% CI 0.09 to 0.47, p = 0.004), but not associated with the change in body mass index (B = 0.9, 95% CI - 1.5 to 3.3, p = 0.46).

CONCLUSIONS

S-zonulin was markedly reduced after the conservative weight loss intervention, and further reduced after bariatric surgery. The reduction in s-zonulin was associated with improvement of diarrhoea, markers of glucose intolerance and liver disease, but not associated with the change in body mass index.

Fecal Microbiota Transplantation for Chronic Liver Diseases: Current Understanding and Future Direction

Chronic liver disease is a major cause of morbidity and mortality worldwide. Even though effective treatments are now available for most chronic viral hepatitis, treatment options for other causes of chronic liver disease remain inadequate. Recent research has revealed a previously unappreciated role that the human intestinal microbiome plays in mediating the development and progression of chronic liver diseases. The recent remarkable success of fecal microbiota transplantation (FMT) in treating Clostridioides difficile demonstrates that the intestinal microbiota can be manipulated to obtain favorable therapeutic benefits and that FMT may become an important component of a total therapeutic approach to effectively treat hepatic disorders.

All disease begins in the (leaky) gut: role of zonulin-mediated gut permeability in the pathogenesis of some chronic inflammatory diseases

Improved hygiene leading to reduced exposure to microorganisms has been implicated as one possible cause for the recent "epidemic" of chronic inflammatory diseases (CIDs) in industrialized countries. That is the essence of the hygiene hypothesis that argues that rising incidence of CIDs may be, at least in part, the result of lifestyle and environmental changes that have made us too "clean" for our own good, so causing changes in our microbiota. Apart from genetic makeup and exposure to environmental triggers, inappropriate increase in intestinal permeability (which may be influenced by the composition of the gut microbiota), a "hyper-belligerent" immune system responsible for the tolerance-immune response balance, and the composition of gut microbiome and its epigenetic influence on the host genomic expression have been identified as three additional elements in causing CIDs. During the past decade, a growing number of publications have focused on human genetics, the gut microbiome, and proteomics, suggesting that loss of mucosal barrier function, particularly in the gastrointestinal tract, may substantially affect antigen trafficking, ultimately influencing the close bidirectional interaction between gut microbiome and our immune system. This cross-talk is highly influential in shaping the host gut immune system function and ultimately shifting genetic predisposition to clinical outcome. This observation led to a re-visitation of the possible causes of CIDs epidemics, suggesting a key pathogenic role of gut permeability. Pre-clinical and clinical studies have shown that the zonulin family, a group of proteins modulating gut permeability, is implicated in a variety of CIDs, including autoimmune, infective, metabolic, and tumoral diseases. These data offer novel therapeutic targets for a variety of CIDs in which the zonulin pathway is implicated in their pathogenesis.

Zonulin Family Peptide Levels in Ascites and Serum in Patients with Liver Cirrhosis: A Preliminary Study

Introduction

Zonulin is a protein that reversibly modulates the permeability of tight junction of the small intestine wall. As the serum concentration of "zonulin family peptides" (ZFPs) is considered to be a sensitive and useful marker of intestinal wall permeability, its serum level may affect the volume of ascites fluid and change in gut microbiota. The aim of the study was to assess the association between concentrations of ZFPs in serum and ascites in relation to the severity of liver cirrhosis.

Methods

The preliminary study included 24 adult patients diagnosed with alcoholic or viral liver cirrhosis. 18 healthy adult subjects were enrolled as the control group. In patients and controls, there were measured serum and ascites (only in patients) ZFPs, serum bilirubin, creatinine, alanine aminotransferase, total protein, and C-reactive protein (CRP).

Results

Cirrhotic patients had lower serum hemoglobin (11.6 vs. 14.3 mg/dL; p < 0.001), platelet count (178 vs. 305 × 10³/mm³; p < 0.01), total protein and albumin (58.6 vs. 74.3 g/dL; p < 0.001, 26.6 vs. 42.3 g/dL; p < 0.001, respectively), and serum ZFPs (30.5 vs. 62.0 ng/mL; p < 0.001) in comparison to controls. In patients with cirrhosis serum bilirubin, C-reactive protein level and INR were higher than in controls (3.07 vs. 0.96 mg/dL; 36.9 vs. 5 mg/L; 1.53 vs. 0.95; p < 0.001, respectively). Patients with low ZFP levels were characterized with lower ascites ZFP levels (0.25 vs. 16.4 ng/mL; p < 0.001) and ascites/serum index (0.011 vs. 0.462; p < 0.001). There were negative correlations between ascites ZFPs and platelet count (R = -0.497; p < 0.01) and positive correlation with INR (R = 0.640; p < 0.001). ZFP index positively correlated with platelet count (R = 0.726; p < 0.001) and negatively with INR (R = -0.392; p = 0.06).

Conclusions

Decrease serum ZFP levels seem to reflect their decreased liver synthesis but not increased gut permeability in patients with liver cirrhosis. The physiologically low level of ZFPs in transudate is increased in exudate.

Risk factors associated with intestinal permeability in an adult population: A systematic review

BACKGROUND

Increased intestinal permeability (IP) involves the loss of integrity between the cells of the small intestine. IP has been suggested to contribute to the pathogenesis and exacerbation of many chronic diseases. Many potential risk factors for IP are proposed in contemporary literature. The purpose of this review is to identify the most significant risk factors for IP.

METHODS

A systematic search of literature published up until September 2018 in the PubMed, EMBASE, CINAHL, and Scopus databases was conducted.

RESULTS

A total of 47 articles met the inclusion criteria. Elevated levels of proinflammatory markers, dyslipidaemia, hyperglycaemia, insulin resistance, anthropometric measurements resembling obesity, advanced disease severity, comorbidity and the consumption of a Western-style diet were identified as the strongest risk factors for altered intestinal integrity. The risk of IP increases when coupled with a multiple disease state or combined with other environmental risk factors. Furthermore, many of the identified risk factors such as anthropometric measurements and biomarkers were external from intestinal health and rather resembled a metabolic-like condition.

CONCLUSIONS

This review identified a number of potential risk factors for IP, ranging from biomarkers to anthropometric measurements, demographics, dietary intake and chronic diseases. These risk factors warrant the attention of clinicians and other healthcare providers to aid the identification of potential patients at risk of altered IP. Further research needs to examine whether the identified risk factors are homogeneous with the diagnosis of IP or whether the disease state influences the association.

Low Serum Levels of Zonulin in Patients with HCV-Infected Chronic Liver Diseases

Aim

The aim of the study was to assess the implication of Zonulin, a mediator protein synthesized by intestine and the liver,in patients with chronic liver diseases.

Materials and methods

Twenty-six patients with chronic liver diseases due to hepatitis C virus (HCV) and hepatitis B virus (HBV) were enrolled in this study. Out of total 26 patients, 17 were diagnosed as chronic hepatitis (CH) and 9 were patients with liver cirrhosis (LC). Twenty-four of these patients were infected with hepatitis C virus (HCV) and the rest two by hepatitis B virus (HBV). The study was conducted at Saiseikai-Imabari Hospital, Imabari, Ehime, Japan. Serum levels of Zonulin along with different parameters of liver function test were measured in all patients and comparative analyses were accomplished.

Results

The serum levels of Zonulin were significantly lower in CH patients compared to controls (p<0.001). Also, the levels of Zonulin were significantly lower in patients with LC compared to CH and normal controls (p<0.001). Further analysis revealed that serum Zonulin was significantly lower in patients with LC having ascites than those without ascites (p <0.05). There was a significant correlation of serum levels of Zonulin with platelet count, cholinesterase, and albumin in patients with chronic liver diseases.

Discussion

Decreased levels of Zonulin may be related to impaired production of this mediator in the diseased liver. It will be tempting to assess the regulation of Zonulin in the liver, a production site of the mediator.

Abbreviations

LC: Liver cirrhosis, CH: Chronic hepatitis, HCV: Hepatitis C virus, HBV: Hepatitis B virus, LGS: Leaky gut syndrome

How to cite this article: Akao T, Morita A, Onji M, Miyake T, Watanabe R, Uehara T, Kawasaki K, Miyaike J, Oomoto M. Low Serum Levels of Zonulin in Patients with HCV-Infected Chronic Liver Diseases. Euroasian J Hepatogastroenterol, 2018;8(2):112-115.