Chronological changes in the gut microbiota and intestinal environment in recipients and donors of living donor liver transplantation

Abstract Background/Purpose This prospective study aimed to investigate the dynamic changes in the gut microbiota (GM) and associated intestinal environment, which were assessed by measuring fecal organic acid (OA) concentrations, during the early period after liver transplantation (LT). To understand the fundamental characteristics of the human GM, data obtained from living donors were also analyzed. Methods Fixed‐point observation was performed in 23 recipients and 21 donors for up to 2 weeks after LT. The GM and OA concentrations were investigated using ribosomal RNA‐targeted reverse‐transcription quantitative polymerase chain reaction and high‐performance liquid chromatography, respectively. Results Before LT, the recipients exhibited remarkable dysbiosis and OA depletion, which were proportional to the model for end‐stage liver disease score. Correlations between the abundances of some specific strains and OA concentrations were observed. After LT, while donor lobectomy caused only slight, transient and reversible changes in the GM and OA concentrations, recipients exhibited delayed recovery in these factors. However, no clear evidence of causality was observed between the GM or OA concentrations and LT outcomes. Conclusions The GM and intestinal environment in LT recipients exhibited characteristics that were clearly different from those in donors. LT did not normalize but rather disrupted the GM during the early post‐LT period, but its negative clinical impact could be minimized with perioperative management.