Effect of Prebiotics and/or Probiotics on Uremic Toxins and Inflammation Markers in Peritoneal Dialysis Patients

Study Overview
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Brief Summary
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End-stage renal disease (ESRD) is a world public health problem, with high morbidity and mortality. Cardiovascular disease is the main cause of mortality in ESRD; uremic toxin retention and inflammation are considered non-traditional risk factors, as they have an active role in atherosclerosis and vascular calcification pathogenesis in dialysis patients. Uremic toxins may be generated by internal protein metabolism, however, some toxins that can't be efficiently eliminated by dialysis such as indoxyl sulphate and p-cresyl sulphate (protein bound toxins), are generated by the microbial metabolism in the large intestine by proteolytic bacteria, and may diffuse easily through the intestinal lumen, as a leaky gut characterizes kidney disease. The gut has been recognized as a potential source of inflammation in ESRD patients; accumulation of nitrogen compounds, presence of gastrointestinal symptoms, dietary changes and multiple drugs and supplements use, stimulates microbiota alterations as bacterial overgrowth and translocation. These phenomena, may active the immune system, promoting local and systemic inflammation, which in turn has negative effects increasing endothelial dysfunction, muscle catabolism, insulin and erythropoietin resistance, and decreases appetite. Some methods have been proposed to decrease inflammation and uremic toxin accumulation, as more efficient dialysis and anti-inflammatory drugs; however, some of them have limited efficacy and high cost. Nutritional treatments focused on modifying intestinal environment, as pre- and probiotics have promising effects by altering production and absorption of uremic toxins and decreasing inflammation; nevertheless, there is scarce information regarding its use and their role in ESRD, particularly in peritoneal dialysis, which is a widely used therapy in México. Furthermore, there is no clinical study comparing the effectiveness of prebiotics, probiotics, and symbiotics on serum concentrations of uremic toxins and inflammation in ESRD patients. It is possible that the administration of a nutritional supplement of probiotics and/or prebiotics decreases the serum concentrations of uremic toxins and inflammation markers in ESRD patients on automated peritoneal dialysis compared to placebo.

Detailed Description
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Objective: The aim of the present study is to evaluate and to compare the effect of a nutritional supplement of probiotics and/or prebiotics on serum concentrations of uremic toxins and inflammatory markers compared to placebo, in automated peritoneal dialysis patients. Sample size: For the sample size calculation a mean differences formula was used, with a 95% confidence level, a 80% sample power and accuracy of 0.05. As a reference, the study of Salmean YA, 2015 was considered; in this study, the administration of pea fiber + inulin during 12 weeks in chronic kidney disease patients, significantly decreased (p<0.05) serum concentrations of p-cresol (5.82 ± 1.72 mg/L) in comparison to placebo (7.25 ± 1.74 mg/L). After substituting formula values and adding 20% of possible losses during follow-up, the sample size is: 28 patients. Additionally, sample size calculation was made considering other outcomes. In the study of Xie LN, 2015, the administration of high-fermentable soluble fiber in ESRD patients on hemodialysis during 6 weeks, significantly decreased (p<0.05) inflammation markers: C-reactive protein (CRP), tumour necrosis factor alpha (TNFa) and interleukin 6 (IL-6) (4.8 ± 4.5 pg/mL, 10.1 ± 1.4 pg/mL, 31.8 ± 5.3 mg/L, respectively) compared to control group (9.5 ± 5.6 pg/mL, 13.1 ± 2.4 pg/mL, 51.5 ± 14.6 mg/L). After substituting the formula, sample size was 19, 7, and 5 for CRP, TNFa and IL-6, respectively. Thus, the highest value was finally used: 28 patients for intervention group. Statistical analysis: Quantitative variables will be shown as mean and standard deviation or median (25-75 percentiles) according to their parametric or non-parametric distribution; Qualitative variables will be shown as frequency and percentage. Intergroup comparisons will be performed with χ2 or Fisher test for qualitative variables and one-way ANOVA or Kruskal-Wallis test for quantitative variables as appropriate. For intra-group comparisons Mc Nemar test will be used for qualitative variables and paired T-test, Wilcoxon, repeated-measures or Friedman ANOVA for quantitative variables as appropriate. An intention to treat analysis will be performed.

Official Title
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Effect of a Nutritional Supplement of Probiotics and/or Prebiotics vs Placebo on Serum Concentrations of Uremic Toxins and Inflammatory Cytokines in Automated Peritoneal Dialysis Patients.

Conditions
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End Stage Renal Failure on Dialysis

Intervention / Treatment
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* Dietary Supplement: Probiotic
* Dietary Supplement: Prebiotic
* Dietary Supplement: Symbiotic
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: >3 months on automated peritoneal dialysis treatment Signed informed consent Exclusion Criteria: ESRD of inflammatory cause (lupus, vasculitis, collagenopathies) Intake of probiotics, prebiotics or fiber in the last 3 months Use of anti-inflammatory drugs or nutritional supplements (immunossuppresants, pentoxifylline, NSAIDs, omega-3) Treated with antibiotics or sevelamer Treated with research drugs or participants in any clinical trial Peritonitis or active infection 2 weeks prior the study Any medical condition affecting intestinal absorption (inflammatory bowel disease, short bowel syndrome, bariatric surgery) or severe dysmotility Severe malnutrition Previous kidney transplantation Serious diseases altering the fina outcomes of the study: decompensated heart failure, chronic liver disease, cancer, AIDS.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Factorial Assignment
Interventional Model Description: Parallel assignment, patients in automated peritoneal dialysis will be randomly assigned to one of the four intervention groups: probiotic, prebiotic, symbiotic and placebo
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Probiotic<br>Subjects receiving probiotic supplementation: 2x108 CFU probiotic bacteria + prebiotic placebo per day during 3 months | Dietary Supplement: Probiotic<br>* The probiotic supplement is composed of the following bacterial strains: Bacillus coagulans, Bacillus subtilis, Bifidobacterium (B) bifidum, B. breve, B. longum, Lactobacillus (L) acidophilus, L. brevis, L. casei, L. helveticus, L. Paracasei, L plantarum, L. rhamnosus, L. salivarus, Lactococcus lactis, Pediococcus acidilactici, Pediococcus parvulus, Weisella confusa, Weisella paramesenteroides<br>|
| Active Comparator: Prebiotic<br>Subjects receiving prebiotic supplementation: 20 g of prebiotic fiber + probiotic placebo per day during 3 months | Dietary Supplement: Prebiotic<br>* The prebiotic fiber is Agave inulin<br>|
| Experimental: Symbiotic<br>Subjects receiving probiotic and prebiotic supplementation: 2x108 CFU probiotic bacteria + 20 g of prebiotic fiber per day during 3 months | Dietary Supplement: Symbiotic<br>* The supplement is a combination of the probiotic product + the prebiotic fiber<br>|
| Placebo Comparator: Placebo<br>Subjects receiving placebo of probiotic and prebiotic per day during 3 months | Dietary Supplement: Placebo<br>* The supplement is a combination of probiotic placebo and prebiotic fiber placebo. Placebo will consist on maltodextrin for both cases.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of uremic toxins from basal to 1 and 3 months | Measurement of serum concentrations of the uremic toxins p-cresyl sulphate (mg/dL) and indoxyl sulphate (mg/dL) by means of liquid chromatography. | Baseline, 1 month and 3 months | 
| Change of uremic toxins from basal to 1 and 3 months | Measurement of serum concentrations of endotoxin (EU/mL) by means of Limulus amebocyte lisate test. | Baseline, 1 month and 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in gut microbiota composition from basal to 1 and 3 months | Determination of fecal bacterial composition by DNA extraction and pyrosequencing analysis. | Baseline, 1 month and 3 months | 
| Change in gastrointestinal symptoms from basal to 1 and 3 months | Measurement of appetite and frequency and severity of gastrointestinal symptoms (nausea, vomiting, bloating, diarrhea, constipation) by means of a gastrointestinal symptoms questionnaire. | Baseline, 1 month and 3 months | 
| Change of inflammatory cytokines from basal to 1 and 3 months | Measurement of serum concentrations of inflammatory cytokines Interleukin-6 (pg/mL), Interleukin-10 (pg/mL) and Tumor Necrosis Factor alpha (pg/mL) by means of ELISA. | Baseline, 1 month and 3 months | 
| Change of inflammatory cytokines from basal to 1 and 3 months | Measurement of serum concentrations of C-Reactive Protein (mg/L) by means of nephelometry. | Baseline, 1 month and 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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dialysis, uremic toxin, inflammation, prebiotics, probiotics