Davide Festi

Gut microbiota, metabolome and immune signatures in patients with uncomplicated diverticular disease

Objective The engagement of the gut microbiota in the development of symptoms and complications of diverticular disease has been frequently hypothesised. Our aim was to explore colonic immunocytes, gut microbiota and the metabolome in patients with diverticular disease in a descriptive, cross-sectional, pilot study. Design Following colonoscopy with biopsy and questionnaire phenotyping, patients were classified into diverticulosis or symptomatic uncomplicated diverticular disease; asymptomatic subjects served as controls. Mucosal immunocytes, in the diverticular region and in unaffected sites, were quantified with immunohistochemistry. Mucosa and faecal microbiota were analysed by the phylogenetic platform high taxonomic fingerprint (HTF)-Microbi.Array, while the metabolome was assessed by 1H nuclear magnetic resonance. Results Compared with controls, patients with diverticula, regardless of symptoms, had a >70% increase in colonic macrophages. Their faecal microbiota showed depletion of Clostridium cluster IV. Clostridium cluster IX, Fusobacterium and Lactobacillaceae were reduced in symptomatic versus asymptomatic patients. A negative correlation was found between macrophages and mucosal Clostridium cluster IV and Akkermansia. Urinary and faecal metabolome changes in diverticular disease involved the hippurate and kynurenine pathways. Six urinary molecules allowed to discriminate diverticular disease and control groups with >95% accuracy. Conclusions Patients with colonic diverticular disease show depletion of microbiota members with anti-inflammatory activity associated with mucosal macrophage infiltration. Metabolome profiles were linked to inflammatory pathways and gut neuromotor dysfunction and showed the ability to discriminate diverticular subgroups and controls. These data pave the way for further large-scale studies specifically aimed at identifying microbiota signatures with a potential diagnostic value in patients with diverticular disease.

Gut Microbiota and Celiac Disease

Recent evidence regarding celiac disease has increasingly shown the role of innate immunity in triggering the immune response by stimulating the adaptive immune response and by mucosal damage. The interaction between the gut microbiota and the mucosal wall is mediated by the same receptors which can activate innate immunity. Thus, changes in gut microbiota may lead to activation of this inflammatory pathway. This paper is a review of the current knowledge regarding the relationship between celiac disease and gut microbiota. In fact, patients with celiac disease have a reduction in beneficial species and an increase in those potentially pathogenic as compared to healthy subjects. This dysbiosis is reduced, but might still remain, after a gluten-free diet. Thus, gut microbiota could play a significant role in the pathogenesis of celiac disease, as described by studies which link dysbiosis with the inflammatory milieu in celiac patients. The use of probiotics seems to reduce the inflammatory response and restore a normal proportion of beneficial bacteria in the gastrointestinal tract. Additional evidence is needed in order to better understand the role of gut microbiota in the pathogenesis of celiac disease, and the clinical impact and therapeutic use of probiotics in this setting.

Differences in liver stiffness values obtained with new ultrasound elastography machines and Fibroscan: A comparative study

BACKGROUND AND AIMS Whether Fibroscan thresholds can be immediately adopted for none, some or all other shear wave elastography techniques has not been tested. The aim of the present study was to test the concordance of the findings obtained from 7 of the most recent ultrasound elastography machines with respect to Fibroscan. METHODS Sixteen hepatitis C virus-related patients with fibrosis ≥2 and having reliable results at Fibroscan were investigated in two intercostal spaces using 7 different elastography machines. Coefficients of both precision (an index of data dispersion) and accuracy (an index of bias correction factors expressing different magnitudes of changes in comparison to the reference) were calculated. RESULTS Median stiffness values differed among the different machines as did coefficients of both precision (range 0.54-0.72) and accuracy (range 0.28-0.87). When the average of the measurements of two intercostal spaces was considered, coefficients of precision significantly increased with all machines (range 0.72-0.90) whereas of accuracy improved more scatteredly and by a smaller degree (range 0.40-0.99). CONCLUSIONS The present results showed only moderate concordance of the majority of elastography machines with the Fibroscan results, preventing the possibility of the immediate universal adoption of Fibroscan thresholds for defining liver fibrosis staging for all new machines.

Liver and spleen stiffness and other noninvasive methods to assess portal hypertension in cirrhotic patients: a review of the literature.

Portal hypertension (PH) is one of the most important causes of morbidity and mortality in patients with chronic liver disease. PH measurement is crucial to stage and predict the clinical outcome of liver cirrhosis. Measurement of hepatic vein pressure gradient is considered the gold standard for assessment of the degree of PH; however, it is an invasive method and has not been used widely. Thus, noninvasive methods have been proposed recently. We critically evaluated serum markers, abdominal ultrasonography, and particularly liver and spleen stiffness measurement, which represent the more promising methods to stage PH degree and to assess the presence/absence of esophageal varices (EV). A literature search was carried out on MEDLINE, EMBASE, Web of Science, and Scopus for articles and abstracts. The search terms used included ‘liver cirrhosis’, ‘portal hypertension’, ‘liver stiffness’, ‘spleen stiffness’, ‘ultrasonography’, and ‘portal hypertension serum biomarker’. The articles cited were selected on the basis of their relevance to the objective of the review. The results of available studies indicate that individually, these methods have a mild accuracy in predicting the presence of EV, and thus they cannot substitute endoscopy to predict EV. When these tests were used in combination, their accuracy increased. In addition to the PH staging, several serum markers and spleen stiffness measurement can predict the clinical outcome of liver cirrhosis with a good accuracy, comparable to that of hepatic vein pressure gradient. In the future, noninvasive methods could be used to select patients requiring further investigations to identify the best tailored clinical management.

Simultaneous Analysis of SEPT9 Promoter Methylation Status, Micronuclei Frequency, and Folate-Related Gene Polymorphisms: The Potential for a Novel Blood-Based Colorectal Cancer Biomarker

One challenge in colorectal cancer (CRC) is identifying novel biomarkers to be introduced in screening programs. The present study investigated the promoter methylation status of the SEPT9 gene in peripheral blood samples of subjects’ positive fecal occult blood test (FOBT). In order to add new insights, we investigated the association between SEPT9 promoter methylation and micronuclei frequency, and polymorphisms in the folate-related pathway genes. SEPT9 promoter methylation, micronuclei frequency, and genotypes were evaluated on 74 individuals’ FOBT positive. Individuals were subjected to a colonoscopy that provided written informed consent for study participation. SEPT9 promoter methylation status was significantly lower in the CRC group than controls (p = 0.0006). In contrast, the CaCo2 cell-line, analyzed as a tissue specific model of colon adenocarcinoma, showed a significantly higher percentage of SEPT9 promoter methylation compared to the CRC group (p < 0.0001). Linear regression analysis showed an inverse correlation between micronuclei frequency and the decrease in the methylation levels of SEPT9 promoter region among CRC patients (β = −0.926, p = 0.0001). With regard to genotype analysis, we showed the involvement of the DHFR polymorphism (rs70991108) in SEPT9 promoter methylation level in CRC patients only. In particular, the presence of at least one 19 bp del allele significantly correlates with decreased SEPT9 promoter methylation, compared to the 19 bp ins/ins genotype (p = 0.007). While remaining aware of the strengths and limitations of the study, this represents the first evidence of a novel approach for the early detection of CRC, using SEPT9 promoter methylation, micronuclei frequency and genotypes, with the potential to improve CRC risk assessment.

Clinical application of faecal calprotectin in ulcerative colitis patients.

Objective Faecal calprotectin (FC) is the most relevant noninvasive biomarker for monitoring inflammatory status, response to treatment and for predicting clinical relapse in ulcerative colitis (UC). The aim of this study was to evaluate the role of FC in predicting both clinical/endoscopic activity and clinical relapse in a large UC patient cohort. Patients and methods A two-phase prospective study was carried out. In the first phase, the relationship between FC and clinical/endoscopic activity was evaluated. In the second phase, a cohort of asymptomatic patients with endoscopic mucosal healing was followed up using clinical and FC level determinations. Results One hundred and twenty-one UC patients were enrolled. The FC concentrations were directly correlated with both clinical and endoscopic activity (r=0.76 and 0.87, respectively, P<0.05) and were capable of differentiating between different degrees of endoscopic severity (P<0.01). An FC cut-off value of 110 &mgr;g/g was highly predictive (95%) of endoscopic activity. Seventy-four patients in clinical remission with mucosal healing were followed up for a year or until relapse and 27% developed a clinical relapse. The FC concentration of nonrelapsed patients (48 &mgr;g/g) versus relapsed patients (218 &mgr;g/g) was significantly different (P<0.01). An FC cut-off value of 193 &mgr;g/g had an accuracy of 89% in predicting clinical relapse. High FC levels were associated with clinical relapse using survival analysis and multivariate analysis. Conclusion Our data strongly support the use of FC for staging the activity of disease, predicting relapse and leading decision-making in a UC setting.

Relationship between indocyanine green retention test, decompensation and survival in patients with Child-Pugh A cirrhosis and portal hypertension.

Indocyanine green retention test (ICG‐r15) is a non‐invasive marker of functional hepatic reserve. Among patients with compensated cirrhosis, ICG‐r15 correlates to the degree of portal hypertension (PH); however, its prognostic relationship with the occurrence of decompensation events still requires clarification.

Usefulness of liver stiffness measurement in predicting hepatic veno-occlusive disease development in patients who undergo HSCT.

Hepatic veno-occlusive disease (VOD), or sinusoidal obstructive syndrome (SOS), is a clinical syndrome characterized by hepatomegaly, ascites, weight gain and jaundice, which can develop more frequently in the first 30 days after hematopoietic stem cell transplantation (HSCT).1, 2 Its incidence, although influenced by diagnostic criteria, has been estimated to be 13.7% (range 0–62.3%) and, in untreated hepatic severe VOD/SOS, it is associated with >80% mortality.3 In this syndrome, sinusoidal endothelial cells and hepatocytes in zone 3 of the hepatic acinus are damaged by toxic metabolites generated during the conditioning regimen.4 The classic VOD pathway develops by the narrowing of the sinusoids, embolization of endothelial cells and increased clot formation, leading to obstruction of the sinusoids, subendothelial and centro-acinar fibrosis and then to portal-central fibrosis resulting in post-sinusoidal portal hypertension, which dominates the clinical picture.5

Non-invasive diagnostic approach to non-alcoholic fatty liver disease: current evidence and future perspectives

Non-alcoholic fatty liver disease is a new epidemic liver disease, thus, its early diagnosis and the identification of those patients with the worst prognosis is mandatory. Liver biopsy is still the diagnostic gold standard, even if it is associated to a significant rate of complications; moreover, the interpretation of histological samples is not always univocal. Several non-invasive alternative scores have been proposed for the diagnostic approach to non-alcoholic fatty liver disease. This article evaluates the performance of the currently available non-invasive diagnostic strategies. The authors also suggest a potential diagnostic algorithm, with two or more non-invasive techniques, to increase the overall accuracy for identifying patients with worst prognosis, and to minimize the recourse to liver biopsy.

Dysbiosis in Celiac Disease Patients With Persistent Symptoms on Gluten-Free Diet: A Condition Similar to that Present in Irritable Bowel Syndrome Patients?

Dysbiosis in Celiac Disease Patients With Persistent Symptoms on Gluten-Free Diet: A Condition Similar to that Present in Irritable Bowel Syndrome Patients?