The mechanisms and clinical translation of stem cell-mediated immunomodulation in erectile dysfunction

Erectile dysfunction (ED) is a heterogeneous disorder in which endothelial and neural dysfunction, smooth-muscle loss, stromal remodeling, and immune dysregulation disrupt cavernosal homeostasis. An immune-inflammatory axis links persistent inflammatory signaling and oxidative stress to neurovascular injury and fibrosis, helping explain why phosphodiesterase type 5 inhibitors (PDE5is) often provide symptomatic rather than disease-modifying benefit in refractory disease. This review examines stem cells and stem cell-derived extracellular vesicles (EVs) as paracrine immunoregulatory therapies. Their effects appear to depend mainly on soluble mediators and vesicle-associated cargo that suppress inflammatory and profibrotic signaling while supporting vascular, smooth-muscle, and neural repair, rather than on direct cell replacement. Although preclinical and early clinical findings are promising, translation remains limited by product heterogeneity, uncertain potency and durability, variable treatment protocols, and inadequate long-term safety data. By integrating disease mechanisms, therapeutic action, and translational requirements, this review supports phenotype-informed development and rigorous clinical testing.