Probiotic Supplementation in Chronic Kidney Disease: A Double-blind, Randomized, Placebo-controlled Trial

International audienceObjective: The objective of the study was to evaluate the effects of probiotic supplementation on the gut microbiota profile and inflammatory markers in chronic kidney disease patients undergoing maintenance hemodialysis (HD). Design and Methods: This was a randomized, double-blind, placebo-controlled study. Forty-six HD patients were assigned to receive 1 of 2 treatments: probiotic (n = 23; Streptococcus thermophilus, Lactobacillus acidophilus e Bifidobacterialongum, 90 billion colony-forming units per day) or placebo (n = 23) daily for 3 months. Blood and feces were collected at baseline and after intervention. The inflammatory markers (C-reactive protein and interleukin-6) were analyzed by immunoenzymatic assay (enzyme-linked immunosorbent assay). Uremic toxins plasma levels (indoxyl sulfate, p-cresyl sulfate, and indole-3-acetic acid) were obtained by Reversed-Phase High-Performance Liquid Chromatography. Routine laboratory parameters were measured by standard techniques. Fecal pH was measured by the colorimetric method, and the gut microbiota profile was assessed by Denaturing Gradient Gel Electrophoresis analysis. Results: Sixteen patients remained in the probiotic group (11 men, 53.6 +/- 11.0 year old, 25.3 +/- 4.6 kg/m(2)) and 17 in the placebo group (10 men, 50.3 +/- 8.5 year old, 25.2 +/- 5.7 kg/m(2)). After probiotic supplementation there was a significant increase in serum urea (from 149.6 +/- 34.2 mg/dL to 172.6 +/- 45.0 mg/dL, P = .02), potassium (from 4.4 +/- 0.4 mmol/L to 4.8 +/- 0.4 mmol/L, P = .02), and indoxyl sulfate (from 31.2 +/- 15.9 to 36.5 +/- 15.0 mg/dL, P = .02). The fecal pH was reduced from 7.2 +/- 0.8 to 6.5 +/- 0.5 (P = .01). These parameters did not change significantly in placebo group. Changes in the percentage delta (Delta) between groups were exhibited with no statistical differences observed. The inflammatory markers and gut profile were not altered by supplementation. Conclusions: Aprobiotic supplementation failed to reduce uremic toxins and inflammatory markers. Therefore, probiotic therapy should be chosen with caution in HD patients. Further studies addressing probiotic therapy in chronic kidney disease patients are needed. (C) 2017 by the National Kidney Foundation, Inc. All rights reserved

From bench to the hemodialysis clinic: protein-bound uremic toxins modulate NF-\kappaB/Nrf2 expression

International audiencePURPOSE: Uremic toxins produced by gut microbiota (indoxyl sulfate-IS, p-cresyl sulfate-p-CS, and indole-3-acetic acid-IAA) accumulate in hemodialysis (HD) patients and exhibit potent inflammatory effects. However, the impact of these toxins on nuclear E2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-kappaB) expression in HD patients remains poorly defined. The aim of this study was to evaluate the association between uremic toxins and Nrf2/NF-kappaB expression in vitro (RAW 264.7 macrophage-like cells) and in peripheral blood mononuclear cells from HD patients. METHODS: Uremic toxins, C-reactive protein (CRP), interleukin-6 (IL-6) and malondialdehyde (MDA) levels were measured in fifteen HD patients and nine healthy individuals. RAW 264.7 macrophage-like cells were incubated with IS, as a prototype of protein-bound uremic toxin. Nrf2 and NF-kappaB expressions were analyzed by RT-qPCR. RESULTS: HD patients presented high levels of inflammatory markers, MDA and uremic toxins. In addition, they presented high NF-kappaB and low Nrf2 expression. Uremic toxins were positively correlated with NF-kappaB expression (IS, rho = 0.58, p \textless 0.003; p-CS, rho = 0.71, p \textless 0.001; IAA, rho = 0.62, p \textless 0.001) and negatively with Nrf2 (IS, rho = - 0.48, p = 0.01; p-CS, rho = - 0.46, p \textless 0.02). Uremic toxins also exhibited positive correlations with CRP and MDA levels. Multivariate analysis revealed that p-CS is a determinant factor of NF-kappaB expression. In RAW 264.7 culture, NF-kappaB mRNA expression was stimulated by IS, while Nrf2 was downregulated. CONCLUSIONS: Thus, uremic toxins may stimulate NF-kappaB mRNA and decrease Nrf2 expression in HD patients and, consequently, trigger inflammation and oxidative stress

Uremia Impacts VE-Cadherin and ZO-1 Expression in Human Endothelial Cell-to-Cell Junctions

Endothelial dysfunction in uremia can result in cell-to-cell junction loss and increased permeability, contributing to cardiovascular diseases (CVD) development. This study evaluated the impact of the uremic milieu on endothelial morphology and cell junction’s proteins. We evaluated (i) serum levels of inflammatory biomarkers in a cohort of chronic kidney disease (CKD) patients and the expression of VE-cadherin and Zonula Occludens-1 (ZO-1) junction proteins on endothelial cells (ECs) of arteries removed from CKD patients during renal transplant; (ii) ECs morphology in vitro under different uremic conditions, and (iii) the impact of uremic toxins p-cresyl sulfate (PCS), indoxyl sulfate (IS), and inorganic phosphate (Pi) as well as of total uremic serum on VE-cadherin and ZO-1 gene and protein expression in cultured ECs. We found that the uremic arteries had lost their intact and continuous endothelial morphology, with a reduction in VE-cadherin and ZO-1 expression. In cultured ECs, both VE-cadherin and ZO-1 protein expression decreased, mainly after exposure to Pi and uremic serum groups. VE-cadherin mRNA expression was reduced while ZO-1 was increased after exposure to PCS, IS, Pi, and uremic serum. Our findings show that uremia alters cell-to-cell junctions leading to an increased endothelial damage. This gives a new perspective regarding the pathophysiological role of uremia in intercellular junctions and opens new avenues to improve cardiovascular outcomes in CKD patients

The Impact of Uremic Toxicity Induced Inflammatory Response on the Cardiovascular Burden in Chronic Kidney Disease

Uremic toxin (UT) retention in chronic kidney disease (CKD) affects biological systems. We aimed to identify the associations between UT, inflammatory biomarkers and biomarkers of the uremic cardiovascular response (BUCVR) and their impact on cardiovascular status as well as their roles as predictors of outcome in CKD patients. CKD patients stages 3, 4 and 5 (n = 67) were recruited and UT (indoxyl sulfate/IS, p-cresil sulfate/pCS and indole-3-acetic acid/IAA); inflammatory biomarkers [Interleukin-6 (IL-6), high sensitivity C reactive protein (hsCRP), monocyte chemoattractant protein-1 (MCP-1), soluble vascular adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble Fas (sFas)] and BUCVRs [soluble CD36 (sCD36), soluble receptor for advanced glycation end products (sRAGE), fractalkine] was measured. Patients were followed for 5.2 years and all causes of death was used as the primary outcome. Artery segments collected at the moment of transplantation were used for the immunohistochemistry analysis in a separate cohort. Estimated glomerular filtration rate (eGFR), circulating UT, plasma biomarkers of systemic and vascular inflammation and BUCVR were strongly interrelated. Patients with plaque presented higher signs of UT-induced inflammation and arteries from CKD patients presented higher fractalkine receptor (CX3CR1) tissue expression. Circulating IS (p = 0.03), pCS (p = 0.007), IL-6 (p = 0.026), sFas (p = 0.001), sCD36 (p = 0.01) and fractalkine (p = 0.02) were independent predictors of total mortality risk in CKD patients. Our results reinforce the important role of uremic toxicity in the pathogenesis of cardiovascular disease (CVD) in CKD patients through an inflammatory pathway