Gastrin for the treatment of acute graft-versus-host disease of the stomach.

Acute graft-versus-host disease (aGVHD) is a major cause of death after allogeneic hematopoietic cell transplantation, and patients with steroid-refractory aGVHD have a dismal prognosis. We have previously shown that the enteroendocrine hormone glucagon-like peptide-2 has tissue regenerative activity in the lower gastrointestinal tract in mice and patients with steroid-refractory aGVHD. Here, we explored the tissue protective effect of the enteroendocrine hormone gastrin for aGVHD of the stomach. We observed that aGVHD caused a loss of gastrin-producing G-cells and parietal cells (PCs) and an increase in pH in the stomach, and allogeneic T cells had infiltrated the stomach wall. Pentagastrin treatment of aGVHD mice rescued the loss of PCs, normalized the pH in the stomach, increased stomach stem cell marker expression and abundance of LGR5+ cells. Gastrin also increased the viability of stomach and small intestine organoids in vitro. Compared with wild-type mice, Gast-/- mice experienced more severe aGVHD in the intestine and liver, which was rescued by pentagastrin treatment. In patients developing aGVHD, low gastrin levels in stomach biopsies were connected to reduced survival. Moreover, gastrin expression in the stomach correlated with aGVHD severity and tissue damage scores in independent patient cohorts. This study delineates the protective role of gastrin in aGVHD of the stomach in mice and patients and provides a rationale for the therapeutic use of pentagastrin in a clinical trial of patients with aGVHD.