<i>Holdemanella biformis</i> augments washed microbiota transplantation for the treatment of radiation enteritis.

Abstract

Current microbiome-based therapeutics face two prominent issues: the limited clinical efficacy of probiotics and the significant variability in the efficacy of microbiota transplantation across different diseases. Although washed microbiota transplantation (WMT) is a new faecal microbiota transplantation, a single therapeutic agent cannot be universally effective for multiple dysbiosis-related diseases. We introduced a new therapeutic concept, X-augmented WMT (X-auWMT), which combines a disease-specific beneficial microbe, 'X', with WMT to enhance its effectiveness. Our goal was to identify a candidate 'X' bacterium to augment WMT efficacy and examine the efficacy of X-auWMT in animal models of radiation enteritis (RE). We conducted a prospective, non-randomised cohort study on a cohort of abdominal or pelvic cancer patients who developed RE after radiotherapy to identify a potential beneficial microbe. We used RE mouse models to evaluate the efficacy of X-auWMT compared with WMT. Multiomics analyses and experiments were undertaken to elucidate the underlying mechanisms. WMT significantly alleviated multiple clinical symptoms in RE patients compared with routine treatments. We identified <i>Holdemanella biformis</i> as a candidate 'X' bacterium within the RE cohort and developed Hb-auWMT. Hb-auWMT significantly mitigated radiation-induced injury compared with WMT, exhibiting enhanced anti-apoptotic effects, improved maintenance of epithelial hypoxia, increased Treg cell levels and elevated butyrate and valerate levels in the RE mouse model. PPAR-γ is an essential pathway for the therapeutic efficacy of Hb-auWMT. This study overcomes the aforementioned recognised limitations with probiotics and microbiota transplantation and provides a new research paradigm in the concept of microbiome-based therapeutics.