Background and objective: Experimental and few clinical studies have indicated great potential of stem cell treatments as both a causal and symptomatic approach for the treatment of male erectile dysfunction (ED). We investigated the effect of a one-time injection of stem-cell derived bioactive molecules in patients with self-reported ED.

Materials and methods: Twenty self-referred male patients with at least one-year history of ED received a one-time intra-penile injection of acellular stem cell-derived bioactive molecules. ED was evaluated by the International Index of Erectile Function questionnaire (IIEF-5), and quality of life was assessed by the Short-Form-36 questionnaire, (SF-36) at baseline and at 6 months. Six male patients with ED, who received a similar injection using saline served as a historic control. Primary outcome was erectile function as measured by IIEF-5 scores. Secondary outcomes were quality of life, assessed by SF-36 questionnaire.

Results: IIEF-5 scores improved from 12.9 \pm 4.47 at baseline to 18 \pm 3.37 at follow-up (p 0.05). No significant difference of IIEF-5 scores were observed in the historic controls during the observation period (11 \pm 2.53 at baseline vs 10.67 \pm 3.5 at follow-up; p > 0.05). Patients, who received stem cell injections, demonstrated significantly enhanced IIEF-5 scores compared to the historic control (p 0.05). Quality of life scores were significantly improved (role limitations due to physical health issues 56.25 \pm 42.82 at baseline vs 68.75 \pm 40.45 at follow-up, p 0.05, energy 51.57 \pm 19.33 at baseline vs 57.75 \pm 12.3 at follow-up, p 0.05, emotional wellbeing 56.32 \pm 16.28 at baseline vs 68.1 \pm 11.73 at follow-up, p 0.05, and social functioning 67.5 \pm 23.79 at baseline vs 76.25 \pm 18.98 at follow-up, p 0.05).

Conclusions: A one-time intracavernous acellular stem cell-derived bioactive molecule injection improves IIEF-5 scores and quality of life in men with ED in this small pilot phase study (ClinicalTrials.gov Identifier: NCT04684602).