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Mitochondrial ATP 6 and 8 polymorphisms in irritable bowel syndrome with diarrhea.

ABSTRACT: AIM:To investigate mitochondrial ATP 6 and 8 polymorphisms in the colon and ileum of patients with irritable bowel syndrome with diarrhea (IBS-D). METHODS:Twenty-eight patients fulfilling the Rome III criteria for IBS-D and 28 healthy subjects were investigated. All study participants underwent screening colonoscopy and mucosal biopsies were obtained from the colon and/or terminal ileum. Genomic DNA was extracted from specimens based on standard protocols. Mitochondrial ATP (MT-ATP) 6 and 8 genes in specimens were polymerase chain reaction amplified and sequenced. Sequencing data were analyzed via Variant Reporter™ Software and compared with the reference sequence from Genbank (accession No. NC_012920) to indicate possible polymorphisms. The protocol was registered at www.clinicaltrials.gov as NCT01028898. RESULTS:Twenty-five polymorphic sites of MT-ATP 6 and 8 genes were detected and 12 of them were missense mutations. A median of two polymorphic sites in MT-ATP genes was found in colon specimens of controls while a median of three polymorphic sites was noted in patients with IBS-D (Mann-Whitney test, P = 0.012). The variants of the colon and ileum specimens from the same subjects were identical in all but one case. Symptom duration in IBS was not found to be a significant factor associated with the mtDNA polymorphism (Spearman correlation, P = 0.592). The mitochondrial DNA change at 8860 was present in all cases of both groups. The frequency of the 8701 polymorphism was found to be the second most frequent; however, no statistical difference was noted between the groups (?(2) test, P = 0.584). CONCLUSION:Patients with IBS-D have a higher incidence of MT-ATP 6 and 8 polymorphisms than healthy subjects, implying that the mtDNA polymorphism may play a role in IBS-D.

SUBMITTER: Wang WF

PROVIDER: S-EPMC3699044 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature

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Mitochondrial ATP 6 and 8 polymorphisms in irritable bowel syndrome with diarrhea.

Wang Wei-Feng WF Li Xin X Guo Ming-Zhou MZ Chen Jian-De JD Yang Yun-Sheng YS Peng Li-Hua LH Wang Yong-Hua YH Zhang Chun-Yan CY Li Hui-Hui HH

World journal of gastroenterology 20130601 24

<h4>Aim</h4>To investigate mitochondrial ATP 6 and 8 polymorphisms in the colon and ileum of patients with irritable bowel syndrome with diarrhea (IBS-D).<h4>Methods</h4>Twenty-eight patients fulfilling the Rome III criteria for IBS-D and 28 healthy subjects were investigated. All study participants underwent screening colonoscopy and mucosal biopsies were obtained from the colon and/or terminal ileum. Genomic DNA was extracted from specimens based on standard protocols. Mitochondrial ATP (MT-AT ...[more]

PMID: 23840124

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Project description:BackgroundPrevious studies have indicated that ramosetron, a 5-hydroxytryptamine-3 receptor antagonist, achieves global improvement in irritable bowel syndrome (IBS) symptoms in male patients with IBS with diarrhea (IBS-D). However, in addition to global assessment it was deemed important to assess "clinically meaningful improvements, focusing on the patient's chief complaint and the severity of major IBS symptoms". We performed a randomized, placebo-controlled, phase IV pilot study to explore and examine efficacy variables that allow such evaluation of ramosetron in male patients with IBS-D.MethodsWe performed a prospective study of 115 male outpatients with IBS-D (according to the Rome III criteria), from June 2009 to December 2009 at 25 centers in Japan. After a one-week baseline period, subjects received either 5 μg of ramosetron (n = 47) or placebo (n = 51) once daily for 12 weeks. To evaluate "clinically meaningful improvements focusing on the severity of major IBS symptoms," the Japanese version of the IBS severity index (IBSSI-J) was used.ResultsChange in IBSSI-J overall score from baseline was -133.5 ± 110.72 in the ramosetron 5 μg group and -108.2 ± 94.44 in the placebo group (P = 0.228) at the last evaluation point. Differences in responder rates for at least a 50% reduction from baseline in IBSSI-J between the ramosetron 5 μg group and the placebo group were over 10%, except Month 1. The monthly responder rate for global assessment of relief of overall IBS symptoms in the ramosetron 5 μg group showed a statistically significant improvement compared to placebo at the second month (44.4% vs 18.4%, P = 0.012). The proportion of patients who had a ≥ 50% reduction in IBSSI-J overall score was 24/37 (64.9%) in the responder group on global assessment and 18/54 (33.3%) in the non-responder group at Week 12.ConclusionsFurther examination will be needed before IBSSI-J can be used in clinical trials of agents for IBS-D. However, this study revealed that response on global assessment was correlated with improvement in the IBSSI-J, suggesting that global assessment reflects improvement of the symptom severity of patients with IBS-D. (Clinicaltrials.gov ID: NCT00918411 Registered 9 June 2009).

Project description:ObjectiveFructose malabsorption is a common digestive disorder in which absorption of fructose in the small intestine is impaired. An abnormality of the main intestinal fructose transporter proteins has been proposed as a cause for fructose malabsorption. However the underlying molecular mechanism for this remains unclear. In this study, we investigated whether carbohydrate response element-binding protein (ChREBP) plays a role in intestinal fructose absorption through the regulation of genes involved in fructose transport and metabolism and ion transport.MethodsWild type (WT) and Chrebp knockout (KO) mice (6 or 8 weeks old) were fed a control diet (55% starch, 15% maltodextrin 10) or high-fructose diet (HFrD, 60% fructose, 10% starch) for 3-12 days. Body weight and food intake were measured, signs of fructose malabsorption were monitored, and the expression of genes involved in fructose transport/metabolism and ion transport was evaluated. Furthermore, transient transfection and chromatin immunoprecipitation were performed to show the direct interaction between ChREBP and carbohydrate response elements in the promoter of Slc2A5, which encodes the fructose transporter GLUT5.ResultsChrebp KO mice fed the control diet maintained a constant body weight, whereas those fed a HFrD showed significant weight loss within 3-5 days. In addition, Chrebp KO mice fed the HFrD exhibited a markedly distended cecum and proximal colon containing both fluid and gas, suggesting incomplete fructose absorption. Fructose-induced increases of genes involved in fructose transport (GLUT5), fructose metabolism (fructokinase, aldolase B, triokinase, and lactate dehydrogenase), and gluconeogenesis (glucose-6-phosphatase and fructose-1,6-bisphosphatase) were observed in the intestine of WT but not of Chrebp KO mice. Moreover the Na+/H+ exchanger NHE3, which is involved in Na+ and water absorption in the intestine, was significantly decreased in HFrD-fed Chrebp KO mice. Consistent with this finding, the high-fructose diet-fed Chrebp KO mice developed severe diarrhea. Results of chromatin immunoprecipitation assays showed a direct interaction of ChREBP with the Glut5 promoter, but not the Nhe3 promoter, in the small intestine. Ectopic co-expression of ChREBP and its heterodimer partner Max-like protein X activated the Glut5 promoter in Caco-2BBE cells.ConclusionsChREBP plays a key role in the dietary fructose transport as well as conversion into lactate and glucose through direct transcriptional control of genes involved in fructose transport, fructolysis, and gluconeogenesis. Moreover, ablation of Chrebp results in a severe diarrhea in mice fed a high-fructose diet, which is associated with the insufficient induction of GLUT5 in the intestine.

Project description:Altered gut microbiota are assumed to be involved in the pathogenesis of irritable bowel syndrome (IBS). However, gut microbiota alterations reported in different studies are divergent and sometimes even contradictory. To better elucidate the relationship between altered gut microbiota and IBS, we characterized fecal microbiota of diarrhea-predominant IBS (IBS-D) patients and further explored the effect of rifaximin on gut microbiota using bacterial 16S rRNA gene-targeted pyrosequencing. In our study, IBS-D patients defined by Rome III criteria and age-and-gender matched healthy controls (HC) were enrolled to investigate the fecal microbiota alterations. These IBS-D patients were then treated with rifaximin for 2 weeks and followed up for 10 weeks. Fecal microbiota alterations, small intestine bacterial overgrowth (SIBO) and gastrointestinal (GI) symptoms of IBS-D patients were analyzed before and after treatment. Our results showed fecal microbiota richness but not diversity was decreased in IBS-D patients as compared to HC and there were alterations of fecal microbiota at different taxonomy levels. The abundant phyla Firmicutes was significantly decreased and Bacteroidetes was increased in IBS-D patients. Moreover, the alterations of predominant fermenting bacteria such as Bacteroidales and Clostridiales might be involved in the pathophysiology of IBS-D. In addition, rifaximin was effective in terms of SIBO eradication and even GI symptoms of IBS-D patients achieved at least 10-week improvement after treatment. Furthermore, rifaximin induced alterations of some special bacteria rather than affected the overall composition of microbiota in IBS-D patients. Meanwhile, a potential decrease in propanoate and butanoate metabolism was found in these IBS-D patients after rifaximin treatment. Taken together, there were alterations of gut microbiota in IBS-D patients as compared to HC. Rifaximin could relieve GI symptoms, modify gut microbiota in IBS-D patients and eradicate SIBO in those patients with SIBO, suggesting an additional therapeutic mechanism of rifaximin in the treatment of IBS-D. Our findings of compositional gut microbiota alterations in IBS-D and the effect of rifaximin on the gut microbiota implied that altered gut microbiota were associated with the pathogenesis of IBS.

Project description:ObjectivesEluxadoline is a mixed μ-opioid receptor (OR) and κ-OR agonist and δ-OR antagonist, approved for the treatment of irritable bowel syndrome with diarrhea (IBS-D). This analysis evaluated the safety and tolerability of eluxadoline 75 and 100 mg twice daily (BID) in one Phase 2 (IBS-2001) and two Phase 3 (IBS-3001 and IBS-3002) studies.MethodsAdults with IBS-D (Rome III criteria) were randomized to placebo or eluxadoline (75 or 100 mg) BID for 12 (IBS-2001), 26 (IBS-3002), or 52 (IBS-3001) weeks. Safety data were pooled. Adverse events (AEs) were assessed, with special focus on opioid-related AEs, including suspected sphincter of Oddi spasm (SOS) events.Results2,776 patients were included in the enrolled set; the safety set comprised 2,814 patients, based on actual treatments received. The most frequent AEs in the placebo and eluxadoline 75 and 100 mg groups were constipation (2.5, 7.4, and 8.1%, respectively) and nausea (5.0, 8.1, and 7.1%, respectively); discontinuation due to constipation was uncommon (0.3, 1.1, and 1.5%, respectively). Ten SOS events (10/1,839; 0.5%) occurred in eluxadoline-treated patients, manifesting as acute abdominal pain with elevated aminotransferases or lipase, or pancreatitis; all occurred in patients without a gallbladder. Eight of these events occurred with the higher dose of eluxadoline, within 1 week of initiation of therapy, and all resolved with eluxadoline discontinuation. There were five events independently adjudicated as pancreatitis not associated with SOS, three of which were associated with heavy alcohol use.ConclusionsEluxadoline was well tolerated in Phase 2 and 3 trials, with constipation and nausea the most common AEs. Consistent with the known adverse effects of opioid agonists, clinically apparent SOS events were observed in eluxadoline-treated patients. All occurred in patients without a gallbladder and the majority were observed in patients on the higher dose of eluxadoline, suggesting a possible association.

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Mitochondrial ATP 6 and 8 polymorphisms in irritable bowel syndrome with diarrhea.

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Mitochondrial ATP 6 and 8 polymorphisms in irritable bowel syndrome with diarrhea.

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