Gut Microbiome Mediated Effects of Inulin Supplementation on Mineral and Bone Metabolism in Hemodialysis Patients

Gut Microbiome Mediated Effects of Inulin Supplementation on Mineral and Bone Metabolism in Hemodialysis Patients

Gut Microbiome Mediated Effects of Inulin Supplementation on Mineral and Bone Metabolism in Hemodialysis Patients

The overall objective of the study is to examine the changes within the gut microbiome after the supplementation of inulin and its effect on markers of mineral metabolism and bone turnover.

In this randomized controlled cross-over study, twenty HD patients (10 male/10 female, aged 20-80) will be recruited from local dialysis clinics in Champaign-Urbana, IL. After baseline testing, patients will be randomized to the intervention group or placebo group (maltodextrin). Patients will consume inulin (females 10g/day, males 15g/day) or maltodextrin (females 10g/day, males 15g/day) for one month, rest for two weeks (washout period), and continue with the other treatment (either inulin or maltodextrin) for another month. Outcomes will be assessed at the beginning of each period and after a month of supplementation at both periods.

Females will ingest 2 doses of 5g/inulin for a total of 10g/inulin/day for four weeks Males will ingest 2 doses of 7.5g/inulin for a total of 15g/inulin/day for four weeks

Females will ingest 2 doses of 5g/maltodextrin for a total of 10g/maltodextrin/day for four weeks Males will ingest 2 doses of 7.5g/maltodextrin for a total of 15g/maltodextrin/day for four weeks

Plasma calcium, phosphorus and magnesium will be assessed by an blood-chemistry autoanalyzer at the beginning and end of each supplementation period. Additionally, parathyroid hormone and fibroblast-growth factor will be assessed by ELISA.

Sclerostin, bone-specific alkaline phosphatase and osteoprotegerin will be assessed by ELISA kits at the beginning and end of each period

Free serum p-cresyl sulfate and indoxyl sulfate: serum (4ml) will be collected on midweek dialysis session and analyzed using an HPLC.

Participants will be asked to collect a complete fecal sample at the beginning and end of Period 1 and 2. V4 regions of the bacterial 16S rRNA gene will be isolated and amplified. Sequencing will be done through Illumina Mi-seq V3 platform. General changes in bacterial diversity and taxa will be analyzed through the open software QIIME.

Inclusion Criteria: Receive HD therapy 3 days per week and for at least 3 months Exclusion Criteria: Sustained hypercalcemia (>3months). Previous major gastrointestinal disease diagnosis (e.g., inflammatory bowel disease and celiac disease). Antibiotic treatment < 2 weeks prior the start of the study.