Bone marrow–derived mesenchymal stromal cell therapy in a rat model of cavernous nerve injury: Preclinical study for approval

Abstract

Background aimsAlthough clinical studies using stem cells to treat erectile dysfunction have been performed or are ongoing, there is little consensus on the optimal protocol. We aimed to develop a protocol optimizing human bone marrow–derived mesenchymal stromal cell (hBMSC) therapy in a rat model of cavernous nerve injury. MethodsWe performed, in order, a dose-finding study, a toxicokinetic study of hBMSCs, and a study to determine the timing and number of cell injections. ResultsFrom the dose-finding study, 1 × 106 cells were selected as the dose per hBMSC injection. From the toxicokinetic study, 14 days was selected as the interval between repeat treatments. In the final study, the ratio of maximal intracavernous pressure to mean arterial pressure was significantly lower in the control group than in the sham group (23.4% vs. 55.1%, P < 0.001). An immediate single injection of hBMSCs significantly improved erectile function compared with the control group (39.8%, P = 0.035), whereas a delayed single injection showed improvement with a marginal trend (38.1%, P = 0.079). All histomorphometric changes were significantly more improved in the immediate or delayed single injection groups than in the control group. Repeat treatments did not provide any benefit for the recovery of erectile function and histomorphometric changes. ConclusionsIntracavernous injection of 1 × 106 hBMSCs results in a recovery of penile erection and histomorphometric changes in a rat model of cavernous nerve injury, even when treatment was delayed until 4 weeks after cavernous nerve injury.