Author Correction: Structural and functional differences in gut microbiome composition in patients undergoing haemodialysis or peritoneal dialysis.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Structural and functional differences in gut microbiome composition in patients undergoing haemodialysis or peritoneal dialysis.

Complications of end-stage renal disease (ESRD) are critically related to inflammation. The gut microbiome is a key driver of inflammation. Since dialysis modalities may differently influence the gut microbiome, we aimed to compare the effects of haemodialysis (HD) and peritoneal dialysis (PD) on patients' gut microbiome composition and function. We therefore studied faecal microbiome composition and function as well as inflammation and gut permeability in 30 patients with ESRD (15 HD, 15 PD) and compared to 21 healthy controls. We found an increase in potentially pathogenic species and a decrease in beneficial species in patients on HD and to a lesser extend in patients on PD when compared to controls. These changes in taxonomic composition also resulted in differences in predicted metagenome functions of the faecal microbiome. In HD but not in PD, changes in microbiome composition were associated with an increase in c-reactive protein (CRP) but not with intestinal inflammation or gut permeability. In conclusion microbiome composition in ESRD differs from healthy controls but also between modes of dialysis. These differences are associated with systemic inflammation and cannot completely be explained by dialysis vintage. The mode of renal replacement therapy seems to be an important driver of dysbiosis in ESRD.

Oxidized plasma albumin promotes platelet-endothelial crosstalk and endothelial tissue factor expression.

Plasma advanced oxidation protein products (AOPPs), a class of pro-inflammatory pathogenic mediators, accumulate in subjects with chronic kidney disease. Whether AOPPs contribute to coagulation abnormalities, which are frequently seen in uremic patients, is unknown. Here we report that AOPPs activate platelets via a CD36-mediated signaling pathway. Activation of signaling pathways by AOPP-platelet interaction resulted in the expression of several platelet activation markers and rapidly induced the expression of CD40 ligand, triggering platelet adhesion to endothelial cells and promoting endothelial tissue factor expression. AOPPs and serum tissue factor levels were considerably increased in end stage renal disease patients on hemodialysis and a significant correlation of AOPPs and serum tissue factor was found. Interestingly, serum levels of AOPPs and tissue factor were substantially lower in stable kidney transplant patients when compared with hemodialysis patients. Given that CD36 is known to transduce the effects of oxidized lipids into platelet hyperactivity, our findings reveal previously unknown pro-thrombotic activities of oxidized plasma albumin via a CD36 dependent pathway.

Triple Therapy with First Generation Protease Inhibitors for Hepatitis C Markedly Impairs Function of Neutrophil Granulocytes.

First-generation HCV protease inhibitors represent a milestone in antiviral therapy for chronic hepatitis C infection (CHC), but substantially increased rates of viral clearance are offset by increased rates of infection and infection-associated deaths, especially of patients with advanced liver disease. We aimed to assess whether first generation protease inhibitors interfere with neutrophil function. We included 108 consecutive, retrospective CHC patients and 44 consecutive, prospective CHC patients who were treated with peginterferon and ribavirin with or without protease inhibitors according to the guidelines in the period of November 2012 to June 2015. 33 healthy volunteers served as controls. Infection data were evaluated in all patients. Neutrophil phagocytosis, oxidative burst, elastase and diamine oxidase levels during 12 weeks of triple (n = 23) or dual therapy (n = 21) were studied in the prospective part. In the retro- and prospective cohorts patients experiencing clinically relevant infections were significantly more frequent during protease inhibitor therapy (31% and 26%) than during therapy with peginterferon and ribavirin (13% and 0%). Neutrophil phagocytosis decreased to 40% of baseline with addition of protease inhibitors to P/R but recovered 6 months after end of treatment. Protease inhibitors also seemed to reduce serum elastase levels but did not impact on gut permeability. Impaired neutrophil function during triple therapy with first generation HCV protease inhibitors may explain the high infection rate associated to these treatments and be of relevance for treatment success and patient survival.

Mode of renal replacement therapy determines endotoxemia and neutrophil dysfunction in chronic kidney disease.

Bacterial infection and sepsis are common complications of chronic kidney disease (CKD). A vicious cycle of increased gut permeability, endotoxemia, inadequate activation of the innate immune system and resulting innate immune dysfunction is hypothesized. We assessed endotoxemia, neutrophil function and its relation to oxidative stress, inflammation and gut permeability in patients with CKD grade 3-5 without renal replacement therapy (CKD group, n = 57), patients with CKD stage 5 undergoing haemodialysis (HD, n = 32) or peritoneal dialysis (PD, n = 28) and patients after kidney transplantation (KT, n = 67) in a cross-sectional observational study. In HD patients, endotoxin serum levels were elevated and neutrophil phagocytic capacity was decreased compared to all other groups. Patients on HD had a significantly higher mortality, due to infections during follow up, compared to PD (p = 0.022). Oxidative stress, neutrophil energy charge, systemic inflammation and gut permeability could not completely explain these differences. Our findings suggest that dialysis modality and not renal function per se determine the development of neutrophil dysfunction and endotoxemia in CKD-patients. HD patients are particularly prone to neutrophil dysfunction and endotoxemia whereas neutrophil function seems to improve after KT. Multi-target approaches are therefore warranted to improve neutrophil function and potentially reduce the rate of infections with patients undergoing haemodialysis.

Lactobacillus casei Shirota Supplementation Does Not Restore Gut Microbiota Composition and Gut Barrier in Metabolic Syndrome: A Randomized Pilot Study.

UNLABELLED: Metabolic syndrome is associated with disturbances in gut microbiota composition. We aimed to investigate the effect of Lactobacillus casei Shirota (LcS) on gut microbiota composition, gut barrier integrity, intestinal inflammation and serum bile acid profile in metabolic syndrome. In a single-centre, prospective, randomised controlled pilot study, 28 subjects with metabolic syndrome received either LcS for 12 weeks (n = 13) or no LcS (n = 15). Data were compared to healthy controls (n = 16). Gut microbiota composition was characterised from stool using 454 pyrosequencing of 16S rRNA genes. Serum bile acids were quantified by tandem mass spectrometry. Zonulin and calprotectin were measured in serum and stool by ELISA. Bacteroidetes/Firmicutes ratio was significantly higher in healthy controls compared to metabolic syndrome but was not influenced by LcS. LcS supplementation led to enrichment of Parabacteroides. Zonulin and calprotectin were increased in metabolic syndrome stool samples but not influenced by LcS supplementation. Serum bile acids were similar to controls and not influenced by LcS supplementation. Metabolic syndrome is associated with a higher Bacteroidetes/Firmicutes ratio and gut barrier dysfunction but LcS was not able to change this. LcS administration was associated with subtle microbiota changes at genus level. TRIAL REGISTRATION: ClinicalTrials.gov NCT01182844.