UCLA

Total-body exposure to radiation causes widespread tissue injury. Damage to the hematopoietic and intestinal stem cell compartments is particularly lethal and mitigators of this damage are critical in providing effective treatment. Parabiosis radiation experiments, in which the vasculatures of two rodents are anastomosed prior to irradiation of one of the animals, have shown that there is a circulating factor that protects mice from radiation-induced intestinal death. Recently reported studies have suggested that growth differentiation factor 11 (GDF11) is responsible for the rejuvenation of stem cells observed in parabiosis experiments involving aging mice. In this study, we investigated the efficacy of GDF11 as a potential mitigator of radiation-induced damage to intestinal stem cells. In ex vivo cultures of intestinal organoids, the number of cells expressing the stem cell marker Lgr5 was increased after irradiation and GDF11 supplementation. Further ex vivo studies to assess stem cell function, measured by the ability to grow new crypt-like structures, did not show increased stem cell activity in response to GDF11 treatment. In addition, GDF11 was unable to improve survival of mice subjected to total-abdominal irradiation. These data demonstrate that GDF11 does not mitigate radiation damage to intestinal stem cells.