Dataset Information

Real-time PCR analysis of the intestinal microbiotas in peritoneal dialysis patients.

ABSTRACT: Bifidobacterium and Lactobacillus can beneficially affect the host by producing acetic acid and lactic acid, which lower pH and thereby inhibit the growth of pathogens or allow the probiotic bacteria to compete with pathogens for epithelial adhesion sites and nutrients. The transmural migration of enteric organisms into the peritoneal cavity can cause peritonitis in peritoneal dialysis (PD) patients. We hypothesized that the composition of the intestinal microbiota with regard to Lactobacillus species and Bifidobacterium species differed between PD patients and healthy controls. The aim of the study was to investigate these differences by real-time PCR analysis of fecal samples. From 1 August 2009 to 31 March 2010, a total of 29 nondiabetic PD patients and 41 healthy controls from China Medical University Hospital were recruited after giving their informed consent. Fecal samples were collected from the PD patients and their age-matched counterparts in the morning using a standardized procedure. DNA extracted from these samples was analyzed by real-time PCR. All bifidobacteria, Bifidobacterium catenulatum, B. longum, B. bifidum, Lactobacillus plantarum, L. paracasei, and Klebsiella pneumoniae were less frequently detected in the patient samples. Dysbiosis (microbial imbalance) may impair intestinal barrier function and increase host vulnerability to pathogen invasion. Further studies are necessary to confirm our findings before clinical trials with probiotic supplementation in PD patients.

SUBMITTER: Wang IK

PROVIDER: S-EPMC3273023 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

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Real-time PCR analysis of the intestinal microbiotas in peritoneal dialysis patients.

Wang I-Kuan IK Lai Hsueh-Chou HC Yu Cheng-Ju CJ Liang Chih-Chia CC Chang Chiz-Tzung CT Kuo Huey-Liang HL Yang Ya-Fei YF Lin Chung-Chih CC Lin Hsin-Hung HH Liu Yao-Lung YL Chang Yi-Chih YC Wu Yi-Ying YY Chen Chu-Huang CH Li Chi-Yuan CY Chuang Feng-Rong FR Huang Chiu-Ching CC Lin Chih-Hsueh CH Lin Hung-Chih HC

Applied and environmental microbiology 20111216 4

Bifidobacterium and Lactobacillus can beneficially affect the host by producing acetic acid and lactic acid, which lower pH and thereby inhibit the growth of pathogens or allow the probiotic bacteria to compete with pathogens for epithelial adhesion sites and nutrients. The transmural migration of enteric organisms into the peritoneal cavity can cause peritonitis in peritoneal dialysis (PD) patients. We hypothesized that the composition of the intestinal microbiota with regard to Lactobacillus s ...[more]

PMID: 22179250

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Project description:Background: The disruption of the circadian clock is associated with inflammatory and immunological disorders. BMAL2, a critical circadian protein, forms a dimer with CLOCK, activating transcription. Extracellular cold-inducible RNA-binding protein (eCIRP), released during sepsis, can induce macrophage endotoxin tolerance. We hypothesized that eCIRP modulates BMAL2 expression and promotes macrophage endotoxin tolerance through triggering receptor expressed on myeloid cells-1 (TREM-1). Methods: C57BL/6 wild-type (WT) male mice were subjected to sepsis by cecal ligation and puncture (CLP). Serum was collected 20 hours post-CLP to assess eCIRP levels. Peritoneal macrophages (PerM) and immortalized bone marrow-derived macrophages (iBMDMs) were seeded into plates and treated with recombinant mouse (rm) CIRP (eCIRP) at various doses. Induction of BMAL2 activation in iBMDM was performed by transfection of BMAL2 CRISPR activation plasmid. Circadian gene expression profiles in eCIRP-treated macrophages were determined by PCR array and confirmed by qPCR. Cytokine levels in the culture supernatants were assessed by ELISA. The interaction of BMAL2 in the PD-L1 promoter was determined by computational modeling and confirmed by the BIAcore assay. Results: PCR array screening of circadian clock genes in peritoneal macrophages treated with eCIRP revealed the elevated expression of BMAL2, CRY1, and PER2. eCIRP serum levels were increased in septic mice. In eCIRP-treated macrophages, TREM-1 deficiency prevented the upregulation of these circadian genes. Macrophages pre-treated with eCIRP exhibited reduced TNFá and IL-6 release upon LPS challenge, indicating macrophage endotoxin tolerance. In addition, eCIRP increased the expression of PD-L1, IL-10, and STAT3, markers of immune tolerance. Interestingly, TREM-1 deficiency reversed eCIRP-induced macrophage endotoxin tolerance. In macrophages, inducible BMAL2 expression correlated with increased PD-L1 expression. In septic human patients, blood monocytes exhibited increased expression of BMAL2 and PD-L1 in comparison to healthy subjects. Computational modeling and BIAcore assay identified a putative binding region of BMAL2 in the PD-L1 promoter, suggesting BMAL2 positively regulates PD-L1 expression in macrophages. Conclusion: eCIRP upregulates BMAL2 expression via TREM-1, leading to macrophage endotoxin tolerance in sepsis. Targeting eCIRP to maintain circadian rhythm may correct endotoxin tolerance and enhance host resistance to bacterial infection.

Project description:BackgroundResults concerning the association between peritoneal dialysis-related peritonitis and mortality in peritoneal dialysis patients are inconclusive, with one potential reason being that the time-dependent effect of peritonitis has rarely been considered in previous studies. This study aimed to evaluate whether peritonitis has a negative impact on mortality in a large cohort of peritoneal dialysis patients. We also assessed the changing impact of peritonitis on patient mortality with respect to duration of follow-up.MethodsThis retrospective cohort study included incident patients who started peritoneal dialysis from 1 January 2006 to 31 December 2011. Episodes of peritonitis were recorded at the time of onset, and peritonitis was parameterized as a time-dependent variable for analysis. We used the Cox regression model to assess whether peritonitis has a negative impact on mortality.ResultsA total of 1321 patients were included. The mean age was 48.1 ± 15.3 years, 41.3% were female, and 23.5% with diabetes mellitus. The median (interquartile) follow-up time was 34 (21-48) months. After adjusting for confounders, peritonitis was independently associated with 95% increased risk of all-cause mortality (hazard ratio, 1.95; 95% confidence interval: 1.46-2.60), 90% increased risk of cardiovascular mortality (hazard ratio, 1.90; 95% confidence interval: 1.28-2.81) and near 4-fold increased risk of infection-related mortality (hazard ratio, 4.94; 95% confidence interval: 2.47-9.86). Further analyses showed that peritonitis was not significantly associated with mortality within 2 years of peritoneal dialysis initiation, but strongly influenced mortality in patients dialysed longer than 2 years.ConclusionsPeritonitis was independently associated with higher risk of all-cause, cardiovascular and infection-related mortality in peritoneal dialysis patients, and its impact on mortality was more significant in patients with longer peritoneal dialysis duration.

Dataset Information

Real-time PCR analysis of the intestinal microbiotas in peritoneal dialysis patients.

Publications

Real-time PCR analysis of the intestinal microbiotas in peritoneal dialysis patients.

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