Non-selective B Adrenergic Receptor Inhibitors Impair Hematopoietic Regeneration in Mice and Humans After Hematopoietic Cell Transplants

Peripheral nerves promote mouse bone marrow regeneration by activating b2 and b3 adrenergic receptor signaling, raising the possibility that non-selective b blockers could inhibit engraftment after hematopoietic cell transplants (HCTs). We observed no effect of b blockers on steady-state mouse hematopoiesis. However, mice treated with a non-selective b blocker (carvedilol), but not a b1-selective inhibitor (metoprolol), exhibited impaired hematopoietic regeneration after syngeneic or allogeneic HCTs. At two institutions, patients who received non-selective, but not b1-selective, b blockers after allogeneic HCT exhibited delayed platelet engraftment and reduced survival. This was particularly observed in patients who received post-transplant chemotherapy for graft-versus-host disease prophylaxis, which also accentuated the inhibitory effect of carvedilol on engraftment in mice. In patients who received autologous HCTs, non-selective b blockers were associated with little or no delay in engraftment. The inhibitory effect of non-selective b blockers after allogeneic HCT was overcome by transplanting larger doses of hematopoietic cells.