Short-term fasting before living kidney donation has an immune-modulatory effect

Background: Short-Term Fasting (STF) is an intervention reducing the intake of calories, without causing undernutrition or micronutrient-related malnutrition. It aims to systemically improve resilience against acute stress. Several (pre-)clinical studies have suggested protective effects of STF, marking the systemic effects STF can induce in respect to surgery and ischemia-reperfusion injury. In addition, STF also affects the number of circulating immune cells. We aim to determine the effect of STF on the abundance and phenotype of different immune cell populations. Methods: Thirty participants were randomly selected from the FAST clinical trial, including living kidneys donors, randomised to a STF-diet or control arm. In an observational cohort sub-study we prospectively included 30 patients who donated blood samples repeatedly during study runtime. Using flow cytometry analyses, immune cell phenotyping was performed on peripheral blood mononuclear cells. Three panels were designed to investigate the presence and activation status of peripheral T cells, B cells, dendritic cells (DCs) and myeloid cells. Results: Eight participants were excluded due to sample constraints. Baseline characteristics showed no significant differences, except for fasting duration. Weight changes were minimal and non-significant across different time intervals, with slight trends towards long-term weight loss pre-surgery. Glucose, insulin, and β-hydroxybutyrate levels differed significantly between groups, reflecting adherence to the fasting diet. Flow cytometry analysis revealed no baseline differences between groups, with high variability within each group. We observed significant changes in immune cell populations due to fasting, particularly in B cells, T cells, and DCs. Discussion: In this study, we found that STF changes the levels and phenotype of immune cells, reducing abundance and activation of T cells and regulatory T cells, increased presence of (naïve) B cells, and elevation of type 1 conventional DCs. Further research should focus on the clinical implications of the changes in immune cell populations and significance of these observed immunological changes. Background: Short-Term Fasting (STF) is an intervention reducing the intake of calories, without causing undernutrition or micronutrient-related malnutrition. It aims to systemically improve resilience against acute stress. Several (pre-)clinical studies have suggested protective effects of STF, marking the systemic effects STF can induce in respect to surgery and ischemia-reperfusion injury. In addition, STF also affects the number of circulating immune cells. We aim to determine the effect of STF on the abundance and phenotype of different immune cell populations. Methods: Thirty participants were randomly selected from the FAST clinical trial, including living kidneys donors, randomised to a STF-diet or control arm. In an observational cohort sub-study we prospectively included 30 patients who donated blood samples repeatedly during study runtime. Using flow cytometry analyses, immune cell phenotyping was performed on peripheral blood mononuclear cells. Three panels were designed to investigate the presence and activation status of peripheral T cells, B cells, dendritic cells (DCs) and myeloid cells. Results: Eight participants were excluded due to sample constraints. Baseline characteristics showed no significant differences, except for fasting duration. Weight changes were minimal and non-significant across different time intervals, with slight trends towards long-term weight loss pre-surgery. Glucose, insulin, and β-hydroxybutyrate levels differed significantly between groups, reflecting adherence to the fasting diet. Flow cytometry analysis revealed no baseline differences between groups, with high variability within each group. We observed significant changes in immune cell populations due to fasting, particularly in B cells, T cells, and DCs. Discussion: In this study, we found that STF changes the levels and phenotype of immune cells, reducing abundance and activation of T cells and regulatory T cells, increased presence of (naïve) B cells, and elevation of type 1 conventional DCs. Further research should focus on the clinical implications of the changes in immune cell populations and significance of these observed immunological changes.

• Type: Other
• Archiver: European Genome-Phenome Archive (EGA)