Gut dysbiosis is associated with poorer long-term prognosis in cirrhosis

BACKGROUNDGut dysbiosis is common in cirrhosis.AIMTo study the influence of gut dysbiosis on prognosis in cirrhosis.METHODSThe case-control study included 48 in-patients with cirrhosis and 21 healthy controls. Stool microbiome was assessed using 16S ribosomal ribonucleic acid gene sequencing. We used modified dysbiosis ratio (MDR): [Bacilli (%) + Proteobacteria (%)]/[Clostridia (%) + Bacteroidetes (%)]. Patients with MDR more the median made up the group with severe dysbiosis, others did the group with non-severe dysbiosis. The follow-up period was 4 years.RESULTSThe mortality rate of patients with severe dysbiosis was significantly higher than that of patients with non-severe dysbiosis (54.2% vs 12.5%; P = 0.001). The presence of severe dysbiosis was independent risk factors for death [hazard ratio = 8.6 × (1.9-38.0); P = 0.005]. The abundance of Enterobacteriaceae (P = 0.002), Proteobacteria (P = 0.002), and Lactobacillaceae (P = 0.025) was increased and the abundance of Firmicutes (P = 0.025) and Clostridia (P = 0.045) was decreased in the deceased patients compared with the survivors. The deceased patients had a higher MDR value than the survivors [0.131 × (0.069-0.234) vs 0.034 × (0.009-0.096); P = 0.004]. If we applied an MDR value of 0.14 as the cutoff point, then it predicted patient death within the next year with a sensitivity of 71.4% and a specificity of 82.9% [area under the curve = 0.767 × (0.559-0.974)]. MDR was higher in patients with cirrhosis than in health controls [0.064 × (0.017-0.131) vs 0.005 × (0.002-0.007); P < 0.001], and in patients with decompensated cirrhosis than in patients with compensated cirrhosis [0.106 × (0.023-0.211) vs 0.033 × (0.012-0.074); P = 0.031]. MDR correlated negatively with prothrombin (r = -0.295; P = 0.042), cholinesterase (r = -0.466; P = 0.014) and serum albumin (r = -0.449; P = 0.001) level and positively with Child–Turcotte–Pugh scale value (r = 0.360; P = 0.012).CONCLUSIONGut dysbiosis is associated with a poorer long-term prognosis in cirrhosis.     

Relationship between intestinal microbial dysbiosis and primary liver cancer

BackgroundIntestinal microbial dysbiosis is involved in liver disease pathogenesis. However, its role in primary liver cancer (PLC), particularly in hepatocarcinogenesis remains unclear. The present study aimed to study the changes in intestinal flora at various stages of PLC and clarify the relationship between intestinal microbes and PLC.MethodsTwenty-four patients with PLC (PLC group), 24 patients with liver cirrhosis (LC group), and 23 healthy control individuals (HC group) were enrolled from October 2016 to October 2017. Stool specimens of the participants were collected and the genomic DNA of fecal bacteria was isolated. High-throughput pyrosequencing of 16S rDNA was used to identify differences in gut bacterial diversity among HC, LC, and PLC groups. We also analyzed the relationship between clinical factors and intestinal microorganisms in LC and PLC groups.ResultsDiversity of Firmicutes tended to decrease from the HC to LC and PLC groups at the phylum level. Among species, Enterobacter ludwigii displayed an increasing trend in the PLC group, wherein the relative abundance of Enterobacter ludwigii in the PLC group was 100 times greater than that in the HC and LC groups. The ratio of Firmicutes/Bacteroidetes was significantly decreased with the disease progression. In addition, the linear discriminant analysis effect size method indicated that Clostridia were predominant in the gut microbiota of the HC group, whereas Enterococcaceae, Lactobacillales, Bacilli and Gammaproteobacteria may be used as diagnostic markers of PLC. Redundancy analysis showed a correlation between intestinal microbial diversity and clinical factors AST, ALT, and AFP. Veillonella showed a significant positive correlation with AFP in the PLC group, whereas Subdoligranulum showed a negative correlation with AFP.ConclusionsThis study indicates that dysbiosis of the gut microbiota might be involved in PLC development and progression.     

Sobrecrecimiento bacteriano del intestino delgado en pacientes con lesión medular

AimSpinal cord injury (SCI) patients may have intestinal dysmotility and digestive symptoms that are associated with small intestinal bacterial overgrowth (SIBO). The aim of this study is to describe the prevalence of SIBO in SCI patients and the risk factors of its development.MethodsTwenty-nine consecutive SCI patients were studied (10 women/19 men; mean age 47 years), 16 with subacute injuries (<9 months) and 13 with chronic injuries (>1 year). Nine patients were affected by tetraplegia and 15 by paraplegia. Each patient underwent a glucose breath test according to the North American Consensus and the presence of abdominal symptoms was evaluated during the test.The results were compared with 15 non-neurological patients with SIBO.ResultsSix patients tested positive for SIBO (21%), all of them affected by SCI in the subacute phase, 6/16 vs. 0/13 in the chronic phase (P<.05) and the majority with tetraplegia, 5/9 vs. 1/19 with paraplegia (P<.05). No statistically significant relationship was found with other clinical characteristics. All the tests were positive for methane or mixed (methane and hydrogen), while only 67% of the controls had methane-predominant production (P>.05).ConclusionSCI patients can develop SIBO, more frequently in the subacute phase and in tetraplegic patients, highlighting a high production of methane. This complication should be considered in neurogenic bowel management.     

Gut Microbiota Characteristics in Children After the Use of Proton Pump Inhibitors

Background/Aims: Prolonged acid suppression from proton pump inhibitor (PPI) has been shown to cause gut microbiota alteration, which may increase the risk of various infections in adults. We aimed to characterize gut microbiota profiles in children after a short-term use of PPI.Materials and Methods: Children aged 1-18 years who underwent PPI therapy were included during April-December 2017. We excluded children who previously used antibiotics or acid suppressants and who had a history of acute gastroenteritis or specific food avoidance one month prior to the enrolment. The stool samples before and after the PPI use were collected for gut microbiota composition. The 16S ribosomal RNA gene sequencing was performed by using Illumina MiSeq. The differences in the gut microbiota profile after the use of PPI were compared to pre-PPI period.Results: We completed stool collection in 20 children (median age of 5.8 years and 60% were female). No significant changes in the overall number of species-level taxonomy categories or predominant bacteria belonging to the phylum (Bacteroidetes) were noted. We found a trend increase in the proportion of the phylum Firmicutes among children living in the designated metropolitan/suburban area (P = .07) and among males (P = .11). In four children with infection-related adverse effects, we noted a nonsignificant increase in the proportion of the phylum Firmicutes after the PPI use (from 35% to 52%, P = .14).Conclusions: Even the total number of and predominant gut microbiota did not significantly change after a four- to eight-week course of PPI therapy; we found a trend of increase in the proportion of the phylum Firmicutes in certain groups of children.     

Altered diversity and composition of gut microbiota in Chinese patients with chronic pancreatitis

Background/ObjectivesGut microbiota alterations in chronic pancreatitis (CP) are seldomly described systematically. It is unknown whether pancreatic exocrine insufficiency (PEI) and different etiologies in patients with CP are associated with gut microbiota dysbiosis.MethodsThe fecal microbiota of 69 healthy controls (HCs) and 71 patients with CP were compared to investigate gut microbiome alterations in CP and the relationship among gut microbiome dysbiosis, PEI and different etiologies. Fecal microbiomes were analyzed through 16S ribosomal RNA gene profiling, based on next-generation sequencing. Pancreatic exocrine function was evaluated by determining fecal elastase 1 activity.ResultsPatients with CP showed gut microbiota dysbiosis with decreased diversity and richness, and taxa-composition changes. On the phylum level, the gut microbiome of the CP group showed lower Firmicutes and Actinobacteria abundances than the HC group and higher Proteobacteria abundances. The abundances of Escherichia-Shigella and other genera were high in gut microbiomes in the CP group, whereas that of Faecalibacterium was low. Kyoto Encyclopedia of Genes and Genomes pathways (lipopolysaccharide biosynthesis and bacterial invasion of epithelial cells) were predicted to be enriched in the CP group. Among the top 5 phyla and 8 genera (in terms of abundance), only Fusobacteria and Eubacterium rectale group showed significant differences between CP patients, with or without PEI. Correlation analysis showed that Bifidobacterium and Lachnoclostridium correlated positively with fecal elastase 1 (r = 0.2616 and 0.2486, respectively, P < 0.05).ConclusionsThe current findings indicate that patients with CP have gut microbiota dysbiosis that is partly affected by pancreatic exocrine function.     

Alteration of fecal tryptophan metabolism correlates with shifted microbiota and may be involved in pathogenesis of colorectal cancer

BACKGROUNDGut tryptophan (Trp) metabolites are produced by microbiota and/or host metabolism. Some of them have been proven to promote or inhibit colorectal cancer (CRC) in vitro and animal models. We hypothesized that there is an alteration of gut Trp metabolism mediated by microbiota and that it might be involved in the pathogenesis of cancer in patients with CRC.AIMTo investigate the features of Trp metabolism in CRC and the correlation between fecal Trp metabolites and gut microbiota.METHODSSeventy-nine patients with colorectal neoplastic lesions (33 with colon adenoma and 46 with sporadic CRC) and 38 healthy controls (HCs) meeting the inclusion and exclusion criteria were included in the study. Their demographic and clinical features were collected. Fecal Trp, kynurenine (KYN), and indoles (metabolites of Trp metabolized by gut microbiota) were examined by ultraperformance liquid chromatography coupled to tandem mass spectrometry. Gut barrier marker and indoleamine 2,3-dioxygenase 1 (IDO1) mRNA were analyzed by quantitative real-time polymerase chain reaction. Zonula occludens-1 (ZO-1) protein expression was analyzed by immunohistochemistry. The gut microbiota was detected by 16S ribosomal RNA gene sequencing. Correlations between fecal metabolites and other parameters were examined in all patients.RESULTSThe absolute concentration of KYN [1.51 (0.70, 3.46) nmol/g vs 0.81 (0.64, 1.57) nmol/g, P = 0.036] and the ratio of KYN to Trp [7.39 (4.12, 11.72) × 10^-3 vs 5.23 (1.86, 7.99) × 10^-3, P = 0.032] were increased in the feces of patients with CRC compared to HCs, while the indoles to Trp ratio was decreased [1.34 (0.70, 2.63) vs 2.46 (1.25, 4.10), P = 0.029]. The relative ZO-1 mRNA levels in patients with CRC (0.27 ± 0.24) were significantly lower than those in HCs (1.00 ± 0.31) (P < 0.001), and the relative IDO1 mRNA levels in patients with CRC [1.65 (0.47-2.46)] were increased (P = 0.035). IDO1 mRNA levels were positively associated with the KYN/Trp ratio (r = 0.327, P = 0.003). ZO-1 mRNA and protein levels were positively correlated with the indoles/Trp ratio (P = 0.035 and P = 0.009, respectively). In addition, the genera Asaccharobacter (Actinobacteria) and Parabacteroides (Bacteroidetes), and members of the phylum Firmicutes (Clostridium XlVb, Fusicatenibacter, Anaerofilum, and Anaerostipes) decreased in CRC and exhibited a positive correlation with indoles in all subjects.CONCLUSIONAlteration of fecal Trp metabolism mediated by microbiota is associated with intestinal barrier function and tissue Trp metabolism, and may be involved in the pathogenesis of CRC.     

Differences of microbiota in small bowel and faeces between irritable bowel syndrome patients and healthy subjects

Objective Several studies suggested that colonic microbiota have impacts on irritable bowel syndrome (IBS) patients. However, the knowledge about the association of small intestine (SI) microbiota with IBS is limited. We aimed to investigate the gut microbiota composition of SI and stool in IBS patients. Materials and methods Biopsies of jejunum mucosa by balloon-assisted enteroscopy and faecal samples from 28 IBS patients and 19 healthy controls were analysed by next-generation sequencing method. Results The three major phyla in SI microbiota of case/control groups were Proteobacteria (32.8/47.7%), Bacteroidetes (25.2/15.3%), and Firmicutes (19.8/11.2%), and those of stool were Bacteroidetes (41.3/45.8%), Firmicutes (40.7/38.2%), and Proteobacteria (15.4/7.1%). Analysis based on the family level, IBS patients had a higher proportion of Veillonellaceae (mean proportion 6.49% versus 2.68%, p?=?0.046) in stool than controls. Prevotellaceae was more abundant in IBS patients than in control group (14.27% versus 6.13%, p?=?0.023), while Mycobacteriaceae (0.06% versus 0.17%, p?=?0.024) and Neisseriaceae (6.40% versus 8.94%, p?=?0.038) was less abundant in IBS patients’ jejunal mucosa than those in controls. This less abundant jejunal Neisseriaceae was associated with more severe IBS (p?=?0.03). The ratio of Firmicutes to Bacteroidetes in the stool of IBS-diarrhoea type patients was approximately three-fold higher, and the ratio of Firmicutes to Actinobacter in SI of IBS-mixed type patients was about nine-fold higher than healthy subjects. Conclusion Higher abundance of colonic Veillonellaceae and SI Prevotellaceae, and lower amount of oral cavity normal flora in proximal SI were found in IBS patients. We may manipulate these bacteria in IBS patients in future studies (ClinicalTrial.gov Number NCT01679730).     

Hydrogen- and Methane-Based Breath Testing and Outcomes in Patients With Heart Failure

BackgroundRecent evidence endorses gut microbiota dysregulation in the pathophysiology of heart failure (HF). Small intestinal bacterial overgrowth (SIBO) might be present in HF and associated with poor clinical outcomes. Lactulose breath testing is a simple noninvasive test that has been advocated as a reliable indicator of SIBO. In patients with HF, we aimed to evaluate the association with clinical outcomes of the exhaled hydrogen (H₂) and methane (CH₄) concentrations through the lactulose breath test.Methods and ResultsWe included 102 patients with HF in which lactulose SIBO breath tests were assessed. Cumulative gas was quantified by the area under the receiver operating characteristic curve of CH₄ (AUC-CH₄) and H₂ (AUC-H₂). Clinical end points included the composite of all-cause death with either all-cause or HF hospitalizations, recurrent all-cause hospitalizations, and recurrent HF hospitalizations. Medians (interquartile ranges) of AUC-H₂ and AUC-CH₄ were 1290 U (520-2430) and 985 U (450-2120), respectively. In multivariable analysis, AUC-H₂ (per 1000 U) was associated with all-cause death/all-cause hospitalization (hazard ratio [HR] 1.21, 95% CI 1.04–1.40; P = .012), all-cause death/HF hospitalization (HR 1.20, 95% CI 1.03–1.40; P = .021), and an increase in the rate of recurrent all-cause (incidence rate ratio [IRR] 1.31, 95% CI 1.14–1.51; P < .001) and HF (IRR 1.41, 95% CI 1.15–1.72; P = .001) hospitalizations. AUC-CH₄ was not associated with any of these end points.ConclusionsAUC-H₂, a safe and noninvasive method for SIBO estimation, is associated with higher risk of long-term adverse clinical events in patients with HF. In contrast, AUC-CH₄ did not show any prognostic value.     

COLIGENTA treatment of small intestinal bacterial overgrowth. Results of an open study.

PurposeThe treatment of small intestinal overgrowth (SIBO) varies according to the center. The present study aimed to evaluate the efficacy of COLIGENTA, an association of colimycin and gentamycin, on SIBO symptomatology and breath test normalizationPatients and MethodsIn this prospective cross-sectional open study, 150 patients with functional bowel disorders and SIBO diagnosed by lactulose hydrogen breath test (LHBT) underwent COLIGENTA oral treatment. A new HLBT was performed 4 weeks after the first HLBT.ResultsThe patients were mainly female (74%), with a mean age of 47.4 ± 16.2 years and a body mass index of 26.2 ± 5.9 kg/m². After treatment, a decrease of expired hydrogen concentration (P<0.001) was found in the entire population. Improvement of gastrointestinal symptoms was found in 129 patients (86%), while the breath test's normalization was found in 62 patients (42%). Logistic regression showed that normalization of bowel symptoms was not associated with demographics, clinical, or hydrogen breath concentration. In contrast, normalization of LHBT was associated with an increase of breath hydrogen concentration at time 100 min during the first test (P = 0.003; OR=1.072; 95%CI= [1.023–1.123]).ConclusionThe present study shows that 10-days of COLIGENTA treatment has a high SIBO clinical improvement rate and can be used as the first or second treatment line.     

Altered metabolism of bile acids correlates with clinical parameters and the gut microbiota in patients with diarrhea-predominant irritable bowel syndrome

BACKGROUNDBile acids (BAs) have attracted attention in the research of irritable bowel syndrome with predominant diarrhea (IBS-D) due to their ability to modulate bowel function and their tight connection with the gut microbiota. The composition of the fecal BA pool in IBS-D patients is reportedly different from that in healthy populations. We hypothesized that BAs may participate in the pathogenesis of IBS-D and the altered BA profile may be correlated with the gut microbiome.AIMTo investigate the role of BAs in the pathogenesis of IBS-D and the correlation between fecal BAs and gut microbiota.METHODSFifty-five IBS-D patients diagnosed according to the Rome IV criteria and twenty-eight age-, sex-, and body mass index-matched healthy controls (HCs) were enrolled in this study at the gastroenterology department of China-Japan Friendship Hospital. First, clinical manifestations were assessed with standardized questionnaires, and visceral sensitivity was evaluated via the rectal distension test using a high-resolution manometry system. Fecal primary BAs including cholic acid (CA) and chenodeoxycholic acid (CDCA), secondary BAs including deoxycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) as well as the corresponding tauro- and glyco-BAs were examined by ultraperformance liquid chromatography coupled to tandem mass spectrometry. The gut microbiota was analyzed using 16S rRNA gene sequencing. Correlations between fecal BAs with clinical features and gut microbiota were explored.RESULTSFecal CA (IBS-D: 3037.66 [282.82, 6917.47] nmol/g, HC: 20.19 [5.03, 1304.28] nmol/g; P < 0.001) and CDCA (IBS-D: 1721.86 [352.80, 2613.83] nmol/g, HC: 57.16 [13.76, 1639.92] nmol/g; P < 0.001) were significantly increased, while LCA (IBS-D: 1621.65 [58.99, 2396.49] nmol/g, HC: 2339.24 [1737.09, 2782.40]; P = 0.002] and UDCA (IBS-D: 8.92 [2.33, 23.93] nmol/g, HC: 17.21 [8.76, 33.48] nmol/g; P = 0.025) were significantly decreased in IBS-D patients compared to HCs. Defecation frequency was positively associated with CA (r = 0.294, P = 0.030) and CDCA (r = 0.290, P = 0.032) and negatively associated with DCA (r = −0.332, P = 0.013) and LCA (r = −0.326, P = 0.015) in IBS-D patients. In total, 23 of 55 IBS-D patients and 15 of 28 HCs participated in the visceral sensitivity test. The first sensation threshold was negatively correlated with CDCA (r = −0.459, P = 0.028) in IBS-D patients. Furthermore, the relative abundance of the family Ruminococcaceae was significantly decreased in IBS-D patients (P < 0.001), and 12 genera were significantly lower in IBS-D patients than in HCs (P < 0.05), with 6 belonging to Ruminococcaceae. Eleven of these genera were negatively correlated with primary BAs and positively correlated with secondary BAs in all subjects.CONCLUSIONThe altered metabolism of BAs in the gut of IBS-D patients was associated with diarrhea and visceral hypersensitivity and might be ascribed to dysbiosis, especially the reduction of genera in Ruminococcaceae.     

Gastric microbiota composition in patients with corpus atrophic gastritis

BackgroundIn corpus atrophic gastritis (CAG), hypochlorhydria makes plausible the overgrowth of intragastric bacteria, whose role in gastric carcinogenesis is under debate.AimsTo characterize the antrum/corpus composition of the gastric bacterial microbiota in CAG patients compared to controls without CAG.MethodsA cross-sectional monocentric study on consecutive patients with known histological diagnosis of CAG undergoing gastroscopy for gastric cancer surveillance and patients without CAG undergoing gastroscopy for dyspepsia or anemia (108 biopsies from 55 patients, median age 61.5). Genomic DNA from one antral and one corpus biopsy from each case (n = 23) and control (n = 32) was extracted. Gastric microbiota was assessed by sequencing hypervariable regions of the 16SrRNA gene.ResultsBacterial abundance and diversity were significantly lower in CAG cases than in controls (p < 0.001). Firmicutes were more frequent in cases, Bacteroidetes and Fusobacteria in controls (p < 0.0001). Streptococcaceae were more abundant in cases (p < 0.0001), Prevotellaceae in controls (p < 0.0001). The genus Streptococcus was positively correlated with severe OLGA/OLGIM stages linked to a higher risk of gastric cancer.ConclusionGastric bacterial microbiota in CAG showed a reduced abundance and complexity but was characterized by higher colonization of Firmicutes, in particular Streptococcus, increased in subjects with severe atrophy/metaplasia stages at higher risk of gastric cancer.     

Changes in gut microbiota composition and diversity associated with post-cholecystectomy diarrhea

BACKGROUNDPost-cholecystectomy diarrhea (PCD) frequently occurs in patients following gallbladder removal. PCD is part of the post-cholecystectomy (PC) syndrome, and is difficult to treat. After cholecystectomy, bile enters the duodenum directly, independent of the timing of meals. The interaction between the bile acids and the intestinal microbes is changed. Therefore, the occurrence of PCD may be related to the change in microbiota. However, little is known about the relationship between the gut microbiota and PCD.AIMTo better understand the role of the gut microbiota in PCD patients.METHODSFecal DNA was isolated. The diversity and profiles of the gut microbiota were analyzed by performing high-throughput 16S rRNA gene sequencing. The gut microbiota were characterized in a healthy control (HC) group and a PC group. Subsequently, the PC group was further divided into a PCD group and a post-cholecystectomy non-diarrhea group (PCND) according to the patients’ clinical symptoms. The composition, diversity and richness of microbial communities were determined and compared.RESULTSIn the PC and HC groups, 720 operational taxonomic units (OTUs) were identified. The PC group had fewer OTUs than the HC group. β-diversity was decreased in the PC group. This indicated decreased microbial diversity in the PC group. Fifteen taxa with differential abundance between the HC and PC groups were identified. In the PCD group compared to the PCND group, significant decreases in microbial diversity, Firmicutes/Bacteroidetes ratio, and richness of probiotic microbiota (Bifidobacterium and Lactococcus), and an increase in detrimental microbiota (Prevotella and Sutterella) were observed. Moreover, a negative correlation was found between Prevotella and Bifidobacterium. Using a Kyoto Encyclopedia of Genes and Genomes functional analysis, it was found that the abundances of gut microbiota involved in lipid metabolism pathways were markedly lower in the PCD group compared to the PCND group.CONCLUSIONThis study demonstrated that gut dysbiosis may play a critical role in PCD, which provides new insights into therapeutic options for PCD patients.     

Exposure to environmental microbiota explains persistent abdominal pain and irritable bowel syndrome after a major flood

Background

After an environmental disaster, the affected community is at increased risk for persistent abdominal pain but mechanisms are unclear. Therefore, our study aimed to determine association between abdominal pain and poor water, sanitation and hygiene (WaSH) practices, and if small intestinal bacterial overgrowth (SIBO) and/or gut dysbiosis explain IBS, impaired quality of life (QOL), anxiety and/or depression after a major flood.

Results

New onset abdominal pain, IBS based on the Rome III criteria, WaSH practices, QOL, anxiety and/or depression, SIBO (hydrogen breath testing) and stools for metagenomic sequencing were assessed in flood victims. Of 211 participants, 37.9% (n = 80) had abdominal pain and 17% (n = 36) with IBS subtyped diarrhea and/or mixed type (n = 27 or 12.8%) being the most common. Poor WaSH practices and impaired quality of life during flood were significantly associated with IBS. Using linear discriminant analysis effect size method, gut dysbiosis was observed in those with anxiety (Bacteroidetes and Proteobacteria, effect size 4.8), abdominal pain (Fusobacteria, Staphylococcus, Megamonas and Plesiomonas, effect size 4.0) and IBS (Plesiomonas and Trabulsiella, effect size 3.0).

Conclusion

Disturbed gut microbiota because of environmentally-derived organisms may explain persistent abdominal pain and IBS after a major environmental disaster in the presence of poor WaSH practices.

     

Serum zonulin levels in patients with liver cirrhosis: Prognostic implications

BACKGROUND Increased gut permeability and bacterial translocation play an important role in liver cirrhosis. Zonulin is a recently recognized protein involved in the disintegration of the intestinal barrier.AIM To investigate possible differences in serum zonulin levels among patients with different cirrhosis stages and their potential prognostic implications.METHODS Consecutive cirrhotic patients who attended our liver clinic were included in the study. Serum zonulin levels, clinical, radiological and biochemical data were collected at baseline. Patients who accepted participation in a regular surveillance program were followed-up for at least 12 mo.RESULTS We enrolled 116 cirrhotics [mean Child-Turcotte-Pugh(CTP) score: 6.2 ± 1.6;model for end-stage liver disease score: 11 ± 3.9]. The causes of cirrhosis were viral hepatitis(39%), alcohol(30%), non-alcoholic fatty liver disease(17%), and other(14%). At baseline, 53% had decompensated cirrhosis, 48% had ascites, and 32% had history of hepatic encephalopathy. Mean zonulin levels were significantly higher in patients with CTP-B class than CTP-A class(4.2 ± 2.4 ng/dL vs 3.5 ± 0.9 ng/dL, P = 0.038), with than without ascites(P = 0.006), and with than without history of encephalopathy(P = 0.011). Baseline serum zonulin levels were independently associated with the probability of decompensation at 1 year(P = 0.039), with an area under the receiving operating characteristic of 0.723 for predicting hepatic decompensation. Higher CTP score(P = 0.021) and portal vein diameter(P = 0.022) were independent predictors of mortality.CONCLUSION Serum zonulin levels are higher in patients with more advanced chronic liver disease and have significant prognostic value in identifying patients who will develop decompensation.     

Gut Microbiome Changes Associated with Epithelial Barrier Damage and Systemic Inflammation during Antiretroviral Therapy of Chronic SIV Infection

Gut dysbiosis is a common feature associated with the chronic inflammation of HIV infection. Toward understanding the interplay of chronic treated HIV infection, dysbiosis, and systemic inflammation, we investigated longitudinal fecal microbiome changes and plasma inflammatory markers in the nonhuman primate model. Following simian immunodeficiency virus (SIV) infection in rhesus macaques, significant changes were observed in several members of the phylum Firmicutes along with an increase in Bacteroidetes. Viral suppression with antiretroviral therapy (ART) resulted in an early but partial recovery of compositional changes and butyrate producing genes in the gut microbiome. Over the course of chronic SIV infection and long-term ART, however, the specific loss of Faecalibacterium prausnitzii and Treponema succinifaciens significantly correlated with an increase in plasma inflammatory cytokines including IL-6, G-CSF, I-TAC, and MIG. Further, the loss of T. succinifaciens correlated with an increase in circulating biomarkers of gut epithelial barrier damage (IFABP) and microbial translocation (LBP and sCD14). As F. prausnitzii and T. succinifaciens are major short-chain fatty acid producing bacteria, their sustained loss during chronic SV-ART may contribute to gut inflammation and metabolic alterations despite effective long-term control of viremia. A better understanding of the correlations between the anti-inflammatory bacterial community and healthy gut barrier functions in the setting of long-term ART may have a major impact on the clinical management of inflammatory comorbidities in HIV-infected individuals.     

Frequency and Factors Associated with Small Intestinal Bacterial Overgrowth in Patients with Cirrhosis of the Liver and Extra Hepatic Portal Venous Obstruction

Spontaneous bacterial peritonitis (SBP), a common complication of cirrhosis of liver, might result from translocation of bacteria from the small bowel. However, there is scanty data on frequency of small intestinal bacterial overgrowth (SIBO) in patients with cirrhosis of the liver. There are no data on SIBO in patients with extra-hepatic portal venous obstruction (EHPVO) in the literature. A total of 174 patients with cirrhosis of the liver, 28 with EHPVO and 51 healthy controls were studied for SIBO using glucose hydrogen breath test (GHBT). Persistent rise in breath hydrogen 12 ppm above basal (at least two readings) was considered diagnostic of SIBO. Of 174 patients (age 47.2 ± 11.9 years, 80.5% male) with cirrhosis due to various causes, 67 (38.5%) were in Child’s class A, 70 (40.2%) class B and 37 (21.7%) class C. Of the 174 patients with cirrhosis, 42 (24.14%) had SIBO as compared to 1 of 51 (1.9%) healthy controls (P < 0.0001). Patients with EHPVO had similar frequency of SIBO compared to healthy controls [2/28 (7.14%) vs 1/51 (1.97%), P = ns]. Frequency of SIBO in Child’s A, B and C was comparable [13 (18.6%) vs 16 (23.9%) and 13 (35.1%), respectively; P = ns]. Presence of SIBO were not related to ascites, etiology of cirrhosis, and degree of liver dysfunction. SIBO is common in patients with cirrhosis of the liver. Patients with EHPVO do not have higher frequency of SIBO than healthy subjects. SIBO in cirrhosis is not related to the degree of derangement in liver function or of portal hypertension.     

Characteristics of the Gut Microbiome of Healthy Young Male Soldiers in South Korea: The Effects of Smoking

Background/AimsSouth Korean soldiers are exposed to similar environmental factors. In this study, we sought to evaluate the gut microbiome of healthy young male soldiers (HYMS) and to identify the primary factors influencing the microbiome composition.MethodsWe prospectively collected stool from 100 HYMS and performed next-generation sequencing of the 16S rRNA genes of fecal bacteria. Clinical data, including data relating to the diet, smoking, drinking, and exercise, were collected.ResultsThe relative abundances of the bacterial phyla Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria were 72.3%, 14.5%, 8.9%, and 4.0%, respectively. Fifteen species, most of which belonged to Firmicutes (87%), were detected in all examined subjects. Using cluster analysis, we found that the subjects could be divided into the two enterotypes based on the gut microbiome bacterial composition. Compared with enterotype 2 subjects, subjects classified as enterotype 1 tended to be characterized by higher frequencies of potentially harmful lifestyle habits (current smoker 55.6% vs 36.6%, p=0.222; heavy drinker 16.7% vs 3.7%, p=0.120; insufficient physical activity 27.8% vs 14.6%, p=0.318). We identified a significant difference in the microbiome compositions of current and noncurrent smokers (p=0.008); the former differed from the latter mainly in a relatively lower abundance of Bifidobacterium species and a higher abundance of Negativicutes.ConclusionsA high abundance of Actinobacteria and low abundance of Bacteroidetes were the main features distinguishing the gut microbiomes of HYMS, and current smokers could be differentiated from noncurrent smokers by their lower abundance of Bifidobacterium and higher abundance of Negativicutes.     

Juvenile ferric iron prevents microbiota dysbiosis and colitis in adult rodents

AIM: To assess whether juvenile chronic ferric iron ingestion limit colitis and dysbiosis at adulthood in rats and mice.METHODS: Two sets of experiments were designed. In the first set, recently weaned mice were either orally administered ferrous (Fe²⁺) iron salt or ferric (Fe³⁺) microencapsulated iron for 6 wk. The last week of experiments trinitrobenzene sulfonic acid (TNBS) colitis was induced. In the second set, juvenile rats received the microencapsulated ferric iron for 6 wk and were also submitted to TNBS colitis during the last week of experiments. In both sets of experiments, animals were sacrificed 7 d after TNBS instillation. Severity of the inflammation was assessed by scoring macroscopic lesions and quantifying colonic myeloperoxidase (MPO) activity. Alteration of the microflora profile was estimated using quantitative polymerase chain reaction (qPCR) by measuring the evolution of total caecal microflora, Bacteroidetes, Firmicutes and enterobacteria.RESULTS: Neither ferrous nor ferric iron daily exposures at the juvenile period result in any effect in control animals at adulthood although ferrous iron repeated administration in infancy limited weight gain. Ferrous iron was unable to limit the experimental colitis (1.71 ± 0.27 MPO U/mg protein vs 2.47 ± 0.22 MPO U/mg protein in colitic mice). In contrast, ferric iron significantly prevented the increase of MPO activity (1.64 ± 0.14 MPO U/mg protein) in TNBS-induced colitis. Moreover, this positive effect was observed at both the doses of ferric iron used (75 and 150 mg/kg per day po - 6 wk). In the study we also compared, in both rats and mice, the consequences of chronic repeated low level exposure to ferric iron (75 mg/kg per day po - 6 wk) on TNBS-induced colitis and its related dysbiosis. We confirmed that ferric iron limited the TNBS-induced increase of MPO activity in both the rodent species. Furthermore, we assessed the ferric iron incidence on TNBS-induced intestinal microbiota dysbiosis. At first, we needed to optimize the isolation and quantify DNA copy numbers using standard curves to perform by qPCR this interspecies comparison. Using this approach, we determined that total microflora was similar in control rats and mice and was mainly composed of Firmicutes and Bacteroidetes at a ratio of 10/1. Ferric juvenile administration did not modify the microflora profile in control animals. Total microflora numbers remained unchanged whichever experimental conditions studied. Following TNBS-induced colitis, the Firmicutes/Bacteroidetes ratio was altered resulting in a decrease of the Firmicutes numbers and an increase of the Bacteroidetes numbers typical of a gut inflammatory reaction. In parallel, the subdominant population, the enterobacteria was also increased. However, ferric iron supplementation for the juvenile period prevented the increase of Bacteroidetes and of enterobacteria numbers consecutive to the colitis in both the studied species at adulthood.CONCLUSION: Rats and mice juvenile chronic ferric iron ingestion prevents colitis and dysbiosis at adulthood as assessed by the first interspecies comparison.     

Gut microbiota dysbiosis in patients with hepatitis B virus-related cirrhosis

Introduction and aimChronic hepatitis B (CHB) is a global epidemic disease that results from hepatitis B virus (HBV) infection and may progress to liver cirrhosis. The relationship between hepatitis B virus-related cirrhosis (HBV-RC) and gut microbiota dysbiosis is still unclear. The aim of this study is to elucidate the compositional and functional characteristics of the gut microbiota in the patients with liver cirrhosis and healthy individuals.Materials and methodsWe analyzed the gut microbiome in patients with HBV-RC and healthy individuals by 16S rRNA sequencing and metagenomic sequencing of fecal samples. A total of 113 genera, 85 families, 57 orders, 44 classes and 21 phyla were performed.ResultsOur results suggests that the composition of the gut microbiota had changed in the early stages of cirrhosis. We further identified more than 17 genera with different richness in compensated and decompensated cirrhosis groups. PICRUSt analysis showed that changes in bacterial composition can lead to significant changes in gene function, which may be one of the causes of liver cirrhosis.ConclusionOur study demonstrated that the composition of gut microbiota changed at different phases of HBV-RC. Gut microbiome transformation may be a biological factor in the progression of cirrhosis.     

High-throughput DNA sequence analysis reveals stable engraftment of gut microbiota following transplantation of previously frozen fecal bacteria

Fecal microbiota transplantation (FMT) is becoming a more widely used technology for treatment of recurrent Clostridum difficile infection (CDI). While previous treatments used fresh fecal slurries as a source of microbiota for FMT, we recently reported the successful use of standardized, partially purified and frozen fecal microbiota to treat CDI. Here we report that high-throughput 16S rRNA gene sequencing showed stable engraftment of gut microbiota following FMT using frozen fecal bacteria from a healthy donor. Similar bacterial taxa were found in post-transplantation samples obtained from the recipients and donor samples, but the relative abundance varied considerably between patients and time points. Post FMT samples from patients showed an increase in the abundance of Firmicutes and Bacteroidetes, representing 75–80% of the total sequence reads. Proteobacteria and Actinobacteria were less abundant (< 5%) than that found in patients prior to FMT. Post FMT samples from two patients were very similar to donor samples, with the Bacteroidetes phylum represented by a great abundance of members of the families Bacteroidaceae, Rikenellaceae and Porphyromonadaceae, and were largely comprised of Bacteroides, Alistipes and Parabacteroides genera. Members of the phylum Firmicutes were represented by Ruminococcaceae, Lachnospiraceae, Verrucomicrobiaceae and unclassified Clostridiales and members of the Firmicutes. One patient subsequently received antibiotics for an unrelated infection, resulting in an increase in the number of intestinal Proteobacteria, primarily Enterobacteriaceae. Our results demonstrate that frozen fecal microbiota from a healthy donor can be used to effectively treat recurrent CDI resulting in restoration of the structure of gut microbiota and clearing of Clostridum difficile.