Vitamin D and Microbiome: Molecular Interaction in Inflammatory Bowel Disease Pathogenesis.

Studies of systemic autoimmune diseases point to characteristic microbial patterns in various diseases, including inflammatory bowel disease (IBD). Autoimmune diseases, and IBD in particular, show a predisposition to vitamin D deficiency, leading to alterations in the microbiome and disruption of intestinal epithelial barrier integrity. This review examines the role of the gut microbiome in IBD and discusses how vitamin D-vitamin D receptor (VDR)-associated molecular signaling pathways contribute to the development and progression of IBD through their effects on gut barrier function, the microbial community, and immune system function. The present data demonstrate that vitamin D promotes the proper function of the innate immune system by acting as an immunomodulator, exerting anti-inflammatory effects, and critically contributing to the maintenance of gut barrier integrity and modulation of the gut microbiota, mechanisms that may influence the IBD development and progression. VDR regulates the biological effects of vitamin D and is related to environmental, genetic, immunologic, and microbial aspects of IBD. Vitamin D influences the distribution of the fecal microbiota, with high vitamin D levels associated with increased levels of beneficial bacterial species and lower levels of pathogenic bacteria. Understanding the cellular functions of vitamin D-VDR signaling in intestinal epithelial cells may pave the way for the development of new treatment strategies for the therapeutic armamentarium of IBD in the near future.

HERACLIS-HDV cohort for the factors of underdiagnosis and prevalence of hepatitis D virus infection in HBsAg-positive patients.

BACKGROUND AND AIMS: Hepatitis D virus (HDV) underdiagnosis remains common. We assessed the HDV screening and prevalence rates in HBsAg-positive patients seen at tertiary liver centres throughout Greece as well as factors affecting HDV diagnosis. METHODS: All adult HBsAg-positive patients seen within the last 5 years were included. Non-screened patients who visited or could be recalled to the clinics over a 6-month period were prospectively tested for anti-HDV. RESULTS: Of 5079 HBsAg-positive patients, 53% had anti-HDV screening (41% before and 12% after study initiation). Pre-study (8%-88%) and total screening rates (14%-100%) varied widely among centres. Screening rates were associated with older age, known risk group, elevated ALT, centre location and size and period of first visit. Anti-HDV prevalence was 5.8% without significant difference in patients screened before (6.1%) or after study initiation (4.7%, p = 0.240). Anti-HDV positivity was associated with younger age, parenteral drug use, born abroad, advanced liver disease and centre location. Overall, HDV RNA detectability rate was 71.6% being more frequent in anti-HDV-positive patients with elevated ALT, advanced liver disease and hepatitis B therapy. CONCLUSIONS: Anti-HDV screening rates and recall capabilities vary widely among Greek liver clinics being higher in HBsAg-positive patients of known risk group with active/advanced liver disease seen at smaller centres, while non-medical factors are also important. Anti-HDV prevalence varies throughout Greece being higher in patients born abroad with younger age, parenteral drug use and advanced liver disease. Viremia is more frequently but not exclusively detected in anti-HDV-positive patients with elevated ALT and advanced liver disease.

miRNA Molecules-Late Breaking Treatment for Inflammatory Bowel Diseases?

MicroRNAs (miRNAs) are a group of non-coding RNAs that play a critical role in regulating epigenetic mechanisms in inflammation-related diseases. Inflammatory bowel diseases (IBDs), which primarily include ulcerative colitis (UC) and Crohn's disease (CD), are characterized by chronic recurrent inflammation of intestinal tissues. Due to the multifactorial etiology of these diseases, the development of innovative treatment strategies that can effectively maintain remission and alleviate disease symptoms is a major challenge. In recent years, evidence for the regulatory role of miRNAs in the pathogenetic mechanisms of various diseases, including IBD, has been accumulating. In light of these findings, miRNAs represent potential innovative candidates for therapeutic application in IBD. In this review, we discuss recent findings on the role of miRNAs in regulating inflammatory responses, maintaining intestinal barrier integrity, and developing fibrosis in clinical and experimental IBD. The focus is on the existing literature, indicating potential therapeutic application of miRNAs in both preclinical experimental IBD models and translational data in the context of clinical IBD. To date, a large and diverse data set, which is growing rapidly, supports the potential use of miRNA-based therapies in clinical practice, although many questions remain unanswered.

The Influence of Single Nucleotide Polymorphisms on Vitamin D Receptor Protein Levels and Function in Chronic Liver Disease.

Single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene have been associated with chronic liver disease. We investigated the role of VDR SNPs on VDR protein levels and function in patients with chronic liver disease. VDR expression levels were determined in peripheral T lymphocytes (CD3+VDR+), monocytes (CD14+VDR+), and plasma from patients (n = 66) and healthy controls (n = 38). Genotyping of SNPs and the determination of expression of VDR/vitamin D-related genes were performed by using qPCR. The effect of FokI SNP on vitamin D-binding to VDR was investigated by molecular dynamics simulations. CD14+VDR+ cells were correlated with the MELD score. The ApaI SNP was associated with decreased CD3+VDR+ levels in cirrhotic patients and with higher liver stiffness in HCV patients. The BsmI and TaqI SNPs were associated with increased VDR plasma concentrations in cirrhotic patients and decreased CD14+VDR+ levels in HCV patients. The FokI SNP was associated with increased CD3+VDR+ levels in cirrhotic patients and controls. VDR polymorphisms were significantly related to the expression of genes critical for normal hepatocyte function and immune homeostasis. VDR expression levels were related to the clinical severity of liver disease. VDR SNPs may be related to the progression of chronic liver disease by affecting VDR expression levels.

Low Urinary Free Cortisol as a Risk Factor for Patients with Variceal Bleeding.

Background and Objectives: Specificity and reliability issues of the current cortisol assessment methods lead to limitations on the accurate assessment of relative adrenal insufficiency. Although free cortisol provides a more accurate evaluation of adrenal cortisol production, the expense and time-consuming nature of these assays make them impractical for routine use. Research has, thus, focused on alternative methods, such as indirectly measuring free cortisol using Coolens' equation or directly assessing salivary cortisol concentration, which is considered a more favorable approach despite associated challenges like sampling issues and infection risks. The aim of this study was to explore correlations between 24 h urinary free cortisol (UFC), free plasma cortisol, serum total cortisol, and salivary cortisol as potential reliable indices of free cortisol in the setting of variceal bleeding. Additionally, we assessed the predictive value of UFC for 6-week mortality and 5-day treatment failure in patients with liver cirrhosis and variceal bleeding. Materials and Methods: A total of 40 outpatients with liver cirrhosis and variceal bleeding were enrolled. Free cortisol levels in serum, saliva, and urine were assessed using the electrochemiluminescence immunoassay method. For the measurement of plasma-free cortisol, a single quadrupole mass spectrometer was employed. The quantification of free cortisol was fulfilled by analyzing the signal response in the negative ESI-MS mode. Results: UFC was significantly correlated to free plasma cortisol. Negative correlations were demonstrated between UFC, the Child-Pugh (CP) score, and C reactive protein (CRP) levels. In the multivariate analysis, CP stage C was associated with 6-week mortality risk and portal vein thrombosis with 5-day treatment failure using Cox regression and binary logistic regression analyses, respectively. Patients who experienced rebleeding, infection, or death (or any combination of these events) presented with lower levels of UFC. Conclusions: This study suggests that low levels of UFC may impose a risk factor for patients with liver cirrhosis and variceal bleeding. The use of UFC as an index of adrenal cortisol production in variceal bleeding warrants further investigation.

Vitamin D-VDR Novel Anti-Inflammatory Molecules-New Insights into Their Effects on Liver Diseases.

There is consistent evidence that vitamin D deficiency is strongly associated with liver dysfunction, disease severity, and poor prognosis in patients with liver disease. Vitamin D and its receptor (VDR) contribute to the regulation of innate and adaptive immune responses. The presence of genetic variants of vitamin D- and VDR-associated genes has been associated with liver disease progression. In our recent work, we summarized the progress in understanding the molecular mechanisms involved in vitamin D-VDR signaling and discussed the functional significance of VDR signaling in specific cell populations in liver disease. The current review focuses on the complex interaction between immune and liver cells in the maintenance of liver homeostasis and the development of liver injury, the interplay of vitamin D and VDR in the development and outcome of liver disease, the role of vitamin D- and VDR-associated genetic variants in modulating the occurrence and severity of liver disease, and the therapeutic value of vitamin D supplementation in various liver diseases. The association of the vitamin D-VDR complex with liver dysfunction shows great potential for clinical application and supports its use as a prognostic index and diagnostic tool.

The burden and management of anemia in Greek patients with inflammatory bowel disease: a retrospective, multicenter, observational study.

BACKGROUND: Anemia is a common extraintestinal manifestation of Inflammatory Bowel Disease (IBD) affecting negatively the patients' quality of life. The aim of this study was to determine the frequency and real-life management of anemia in IBD patients in Greece. METHODS: This study was conducted in 17 Greek IBD referral centers. Demographic, clinical, laboratory, IBD and anemia treatment data were collected and analyzed retrospectively. RESULTS: A total of 1394 IBD patients [560 ulcerative colitis (UC), 834 Crohn's disease (CD)] were enrolled. Anemia at any time was reported in 687 (49.3%) patients of whom 413 (29.6%) had episodic and 274 (19.7%) had recurrent/persistent anemia. Anemia was diagnosed before IBD in 45 (6.5%), along with IBD in 269 (39.2%) and after IBD in 373 (54.3%) patients. In the multivariate analysis the presence of extraintestinal manifestations (p = 0.0008), IBD duration (p = 0.026), IBD related surgeries and hospitalizations (p = 0.026 and p = 0.004 accordingly) were risk factors of recurrent/persistent anemia. Serum ferritin was measured in 839 (60.2%) IBD patients. Among anemic patients, 535 (77.9%) received treatment. Iron supplementation was administered in 485 (90.6%) patients, oral in 142 (29.3%) and intravenous in 393 (81%). CONCLUSIONS: The frequency of anemia in IBD patients, followed at Greek referral centers, is approximately 50%. Development of recurrent/persistent anemia may be observed in 20% of cases and is independently associated with the presence of extraintestinal manifestations, IBD duration, IBD related surgeries and hospitalizations. Anemia treatment is administered in up to [Formula: see text] of anemia IBD patients with the majority of them receiving iron intravenously.

Gut-origin sepsis in the critically ill patient: pathophysiology and treatment.

INTRODUCTION: Gut permeability is increased in critically ill patients, and associated with the development of the systemic inflammatory response syndrome and multiple organ dysfunction syndrome (MODS). The pathogenetic link(s) and potential therapies are an area of intense research over the last decades. METHODS: We thoroughly reviewed the literature on gut-origin sepsis and MODS in critically ill patients, with emphasis on the implicated pathophysiological mechanisms and therapeutic interventions. FINDINGS: Intestinal barrier failure leading to systemic bacterial translocation associated with MODS was the predominant pathophysiological theory for several years. However, clinical studies with critically ill patients failed to provide the evidence of systemic spread of gut-derived bacteria and/or their products as a cause of MODS. Newer experimental data highlight the role of the mesenteric lymph as a carrier of gut-derived danger-associated molecular patterns (DAMPs) to the lung and the systemic circulation. These substances are recognized by pattern recognition receptor-bearing cells in diverse tissues and promote proinflammatory pathways and the development MODS. Therefore, the gut becomes a pivotal proinflammatory organ, driving the systemic inflammatory response through DAMPs release in mesenteric lymph, without the need for systemic bacterial translocation. CONCLUSIONS: There is an emerging need for application of sensitive non-invasive and easily measured biomarkers of early intestinal injury (e.g., citrulline, intestinal fatty acid protein, and zonulin) in our everyday clinical practice, guiding the early pharmacological intervention in critically ill patients to restore or prevent intestinal injury and improve their outcomes.

Response to hepatitis B vaccination in patients with liver cirrhosis.

Hepatitis B vaccination is strongly recommended for all infants and children but also for adults who are at risk of HBV infection. Attempts to immunize patients with liver cirrhosis have been proven relatively ineffective, and several strategies have already been used to improve the immune response in this group. The primary aim of this review is to examine, discuss, and summarize the immunogenicity of hepatitis B vaccination in patients with liver cirrhosis. MEDLINE search identified 11 studies (n = 961). The dose of the vaccine and the schedule of the vaccination varied. The response rates to the HBV vaccination ranged from 16% to 87% among patients with cirrhosis regardless of the number and vaccine dose. In particular, patients who received the standard dose of vaccination achieved seroprotection rates ranged from 16% to 79% (mean response rate 38%) and those who received a double dose achieved relatively better seroprotection rates (range: 26%-87%; mean response rate 53%). The overall mean response rate to the HBV vaccination was 47%. In conclusion, cirrhotic patients achieve lower seroprotection rates after the completion of HBV vaccination series. Several strategies have tried to improve the immunogenicity; however, there is a great need for additional studies to further explore (1) the immune response in relation to poor vaccination responsiveness confounding factors, (2) novel strategies to improve immunogenicity, and (3) the immune mechanism underlying the differences in response rates to HBV vaccination.

Expression of α-Defensins, CD20+ B-lymphocytes, and Intraepithelial CD3+ T-lymphocytes in the Intestinal Mucosa of Patients with Liver Cirrhosis: Emerging Mediators of Intestinal Barrier Function.

AIM: The present study investigates the role of innate and adaptive immune system of intestinal mucosal barrier function in cirrhosis. METHODS: Forty patients with decompensated (n = 40, group A), 27 with compensated cirrhosis (n = 27, group B), and 27 controls (n = 27, group C) were subjected to duodenal biopsy. Expression of α-defensins 5 and 6 at the intestinal crypts was evaluated by immunohistochemistry and immunofluorescence. Serum endotoxin, intestinal T-intraepithelial, and lamina propria B-lymphocytes were quantified. RESULTS: Cirrhotic patients presented higher endotoxin concentrations (p < 0.0001) and diminished HD5 and HD6 expression compared to healthy controls (p = 0.000287, p = 0.000314, respectively). The diminished HD5 and HD6 expressions were also apparent among the decompensated patients compared to compensated group (p = 0.025, p = 0.041, respectively). HD5 and HD6 expressions were correlated with endotoxin levels (r = -0.790, p < 0.0001, r = - 0.777, p < 0.0001, respectively). Although intraepithelial T-lymphocytes were decreased in group A compared to group C (p = 0.002), no notable alterations between groups B and C were observed. The B-lymphocytic infiltrate did not differ among the investigated groups. CONCLUSIONS: These data demonstrate that decreased expression of antimicrobial peptides may be considered as a potential pathophysiological mechanism of intestinal barrier dysfunction in liver cirrhosis, while remodeling of gut-associated lymphoid tissue as an acquired immune response to bio-pathogens remains an open field to illuminate.

Prognostic Models for Survival in Patients with Stable Cirrhosis: A Multicenter Cohort Study.

BACKGROUND: Two models are mostly used to predict survival in cirrhosis: the Child-Pugh score (CP score) and the model for end-stage liver disease score (MELD score). AIMS: The aim of this study is to evaluate the CP score and the MELD score for short- and long-term prognosis in cirrhosis, as well as CP-creatinine score, MELD-Na score, and UKELD score. METHODS: One thousand and forty-seven patients from five referral centers were included: men/women: 620/427, median age: 58 years (IQR 48-66), median follow-up: 33 months (IQR 12-74), CP (A/B/C): 493/357/147, CP score: 7 (IQR 5-9), MELD score: 12 (IQR 9-16). The performance of each score was evaluated by the Cox hazard model in terms of their: discrimination ability (C-index and Somer's D) and calibration (3, 12 months). Internal validation was done with bootstrapping (100 samples). RESULTS: Three hundred and fifty-two patients (33.6%) died. All scores were significantly associated with overall mortality, when assessed by univariate Cox analysis. CP-creatinine score performed significantly better than all other scores [bootstrap C-index 0.672, 95% CI 0.642-0.703, bootstrap Somer's D 0.344 (0.285-0.401)], apart from CP score, which showed similar performance. Inclusion in the multivariable Cox model of age together with CP-creatinine score improved the discriminative ability of the model [bootstrap C-index (95% CI) 0.700 (0.661-0.740)]. In terms of calibration, CP-creatinine score was the best for both 3- and 12-month survival in the total population. CONCLUSIONS: CP score and CP-creatinine score have better prognostic value compared to MELD score, MELD-Na score, and UKELD score for predicting short- and long-term mortality in patients with stable cirrhosis.

Intussuscepted Polypoid Meckel's Diverticulum Presenting With Gastrointestinal Bleeding in a Young Adult.

A 22-year-old female patient with a recent hospitalization for gastrointestinal bleeding presented with recurrent hematochezia and a positive shock index. Previous investigations, including endoscopy and wireless small bowel capsule, were non-diagnostic. CT angiography revealed extravasation in the ileum. Initial tests like technetium-99m scintigraphy and ileocolonoscopy were negative. Repeat wireless small bowel capsule identified a partially ulcerated polypoid mass in the distal ileum. At surgical exploration, an intussuscepted Meckel's diverticulum was identified and resected. A histopathologic examination confirmed the diagnosis. Meckel's diverticulum is a rare cause of gastrointestinal bleeding in adults. Preoperative diagnosis can be challenging. Reports of a polypoid morphology are very scarce in indexed literature and mostly derive from investigation with device-assisted enteroscopy. We report this extremely rare finding at capsule endoscopy to raise clinician awareness and to discuss diagnostic difficulties associated with similar cases, such as the negative scintigraphy result and the optimal timing of repeat capsule endoscopy.

Altered Expression of Intestinal Tight Junctions in Patients with Chronic Kidney Disease: A Pathogenetic Mechanism of Intestinal Hyperpermeability.

BACKGROUND: Systemic inflammation in chronic kidney disease (CKD) is associated (as a cause or effect) with intestinal barrier dysfunction and increased gut permeability, with mechanisms not yet fully understood. This study investigated different parameters of the intestinal barrier in CKD patients, especially tight junction (TJ) proteins and their possible association with systemic endotoxemia and inflammation. METHODS: Thirty-three patients with stage I-IV CKD (n = 17) or end-stage kidney disease (ESKD) (n = 16) and 11 healthy controls underwent duodenal biopsy. Samples were examined histologically, the presence of CD3+ T-lymphocytes and the expression of occludin and claudin-1 in the intestinal epithelium was evaluated by means of immunohistochemistry, circulating endotoxin concentrations were determined by means of ELISA and the concentrations of the cytokines IL-1ß, IL-6, IL-8, IL-10 and TNF-α in serum were measured using flow cytometry. RESULTS: Patients with stage I-IV CKD or ESKD had significantly higher serum endotoxin, IL-6, IL-8 and IL-10 levels compared to controls. Intestinal occludin and claudin-1 were significantly decreased, and their expression was inversely correlated with systemic endotoxemia. Regarding occludin, a specific expression pattern was observed, with a gradually increasing loss of its expression from the crypt to the tip of the villi. CONCLUSION: The expression of occludin and claudin-1 in enterocytes is significantly reduced in patients with CKD, contributing to systemic endotoxemia and inflammatory responses in these patients.

Altered Expression of Intestinal Tight Junction Proteins in Heart Failure Patients with Reduced or Preserved Ejection Fraction: A Pathogenetic Mechanism of Intestinal Hyperpermeability.

Although intestinal microbiota alterations (dysbiosis) have been described in heart failure (HF) patients, the possible mechanisms of intestinal barrier dysfunction leading to endotoxemia and systemic inflammation are not fully understood. In this study, we investigated the expression of the intestinal tight junction (TJ) proteins occludin and claudin-1 in patients with HF with reduced (HFrEF) or preserved ejection fraction (HFpEF) and their possible association with systemic endotoxemia and inflammation. Ten healthy controls and twenty-eight patients with HF (HFrEF (n = 14), HFpEF (n = 14)) underwent duodenal biopsy. Histological parameters were recorded, intraepithelial CD3+ T-cells and the expression of occludin and claudin-1 in enterocytes were examined using immunohistochemistry, circulating endotoxin concentrations were determined using ELISA, and concentrations of cytokines were determined using flow cytometry. Patients with HFrEF or HFpEF had significantly higher serum endotoxin concentrations (p < 0.001), a significantly decreased intestinal occludin and claudin-1 expression (in HfrEF p < 0.01 for occludin, p < 0.05 for claudin-1, in HfpEF p < 0.01 occludin and claudin-1), and significantly increased serum concentrations of IL-6, IL-8, and IL-10 (for IL-6 and IL-10, p < 0.05 for HFrEF and p < 0.001 for HFpEF; and for IL-8, p < 0.05 for both groups) compared to controls. Occludin and claudin-1 expression inversely correlated with systemic endotoxemia (p < 0.05 and p < 0.01, respectively). Heart failure, regardless of the type of ejection fraction, results in a significant decrease in enterocytic occludin and claudin-1 expression, which may represent an important cellular mechanism for the intestinal barrier dysfunction causing systemic endotoxemia and inflammatory response.

Hepatitis C in patients with ß-thalassemia major. A single-centre experience.

Chronic hepatitis C (CHC) and iron overload are the main causes of liver disease in ß-thalassemia major (ßTM). There is limited data regarding the course of CHC in this population. All patients (n=144) from the thalassemia centre of the University Hospital of Patras were evaluated (January 1981 to June 2012). Patients were classified into group A (n=57), which consisted of patients with CHC, who either had received antiviral treatment (n=49) or not (n=8), and group B which included 87 patients without CHC. Nineteen patients died during follow-up (median: 257.5 months (1-355)). Survival rates were 84.2 % and 88.5 % for group A and B, respectively. The causes of death were heart failure (63.2 %), accident (10.5 %), sepsis (5.3 %), liver failure (5.3 %), hepatocellular carcinoma (HCC) (5.3 %), non-Hodgkin lymphoma (5.3 %) and multiorgan failure (5.3 %). There were no differences in total survival between the two groups (p=0.524). In the multivariate analysis, survival was neither correlated with CHC (p=ns), nor with anti-HCV treatment (p=ns), whereas independent negative predictors were presence of heart failure (p<0.001), presence of malignancy other than HCC (p=0.001) and non-adherence to chelation treatment (p=0.013). Predictive factors for the development of cirrhosis were: CHC (p<0.001), age>35 years (p=0.007), siderosis grade 3/4 (p=0.029) and splenectomy (p=0.001); however, multivariately, only siderosis grade 3/4 was found to be significant (p=0.049). In this study, survival of patients with ßTM was mainly associated with heart failure, presence of malignancy other than HCC and non-adherence to chelation treatment, rather than with liver disease. Multicentre studies need to be designed to define more accurately the indications of antiviral treatment in this population.

Intestinal mucosal proliferation, apoptosis and oxidative stress in patients with liver cirrhosis.

BACKGROUND: Intestinal mucosal barrier dysfunction in liver cirrhosis and its implicated mechanisms is of great clinical importance because it is associated with the development of serious complications from diverse organs through promotion of systemic endotoxemia. AIM: The present study was designed to investigate whether enterocytes' proliferation, apoptosis and intestinal oxidative stress are altered in the intestinal mucosa of patients with compensated and decompensated liver cirrhosis. MATERIAL AND METHODS: Twelve healthy controls (group A) and twenty four cirrhotic patients at a compensated (n = 12, group B) or decompensated condition (n = 12, group C) were subjected to duodenal biopsy. In intestinal specimens mucosal apoptotic and mitotic activity and their ratio were recorded by means of morphological assessment and mucosal lipid hydroperoxides were measured. Plasma endotoxin concentration, an index of gut barrier function, was also determined. RESULTS: Cirrhotic patients presented significantly higher serum endotoxin concentrations as compared to healthy controls (P < 0.001), whilst endotoxemia was higher in decompensated disease (P < 0.05 vs. compensated cirrhosis). Intestinal mucosal mitotic count was significantly lower in patients with compensated and decompensated cirrhosis compared to controls (P < 0.01, respectively), whilst a trend towards increased apoptosis was recorded. The mitotic/apoptotic ratio was significantly reduced in groups B (P < 0.05) and C (P < 0.01) as compared to controls. Intestinal lipid peroxidation was significantly increased in decompensated cirrhotics (P < 0.001 vs. groups A and B). CONCLUSIONS: The present study demonstrates for the first time that human liver cirrhosis is associated with decreased intestinal mucosal proliferation and proliferation/apoptosis ratio even at early stages of cirrhosis and increased intestinal oxidative stress in advanced liver disease.