Sixteen Weeks Of Aerobic Training & Resistant Starch Supplementation Reduce Indoxyl Sulphate In Kidney Patients

PURPOSE: We examined the effects of 16 weeks of moderate-intensity aerobic exercise training and Hi Maize 260 resistant starch (RS) supplementation on markers of inflammation, oxidative stress, and indoxyl sulfate (IS) level as a marker of uremic toxins levels in patients with stage 3-4 chronic kidney disease (CKD). METHODS: This was a double-blind, placebo-controlled, parallel-arm, randomized controlled trial. We randomized 21 participants (Control C; n = 6, Exercise-E; n = 4, RS; n = 4, Exercise & RS - ERS; n = 7), after which the exercise intervention was stopped due to the COVID-19 pandemic. Participants attended two baseline visits with follow-up visits 8 (wk8) and 16 weeks (wk16) later. A cardiopulmonary exercise test was performed during visit 1 and used to compute 55-65% of peak oxygen uptake for the exercise groups. The training was performed 3 days per week for 45-50 minutes per session under the supervision of a trainer. Fasting blood samples were collected at Baseline, wk8, and wk16 and analyzed for markers of inflammation, (IL-6, TNFα,) oxidative stress (MDA), and IS. For week 1, the dose of RS was 15 g/day. The dose was then increased to 33 g/day for weeks 2-16. RESULTS: A linear mixed effects model was calculated to determine if the change in the dependent variables across the three assessment times differed by RS and exercise conditions. Due to the small sample size, changes in most variables did not significantly differ across the four groups. However, the three-way interaction was significant for IS (p = .02) with a large effect size, Cohen’s d = 0.22. The ERS group means showed a decrease in IS (mg/dl) between baseline [M = 2.87, SD = 1.19) and wk8 (M = 2.21, SD = 0.80) and then no change at wk16 (M = 2.23, SD = 0.65), while the other groups showed an increase in IS between wk8 and wk16. CONCLUSION: Exercise training and RS seem to work synergistically to reduce IS, a key uremic toxin in patients with moderate to severe CKD. This observation needs to be followed up with a fully powered study.