Mesenchymal Stem Cell and Exosome Therapy for Diabetic Erectile Dysfunction

The goal of this prospective randomized controlled clinical study is to evaluate the effectiveness and safety of intracavernosal injections of umbilical cord-derived mesenchymal stem cells (MSCs) and umbilical cord-derived MSC-derived exosomes in men aged 25 to 75 years with diabetic erectile dysfunction (ED) who have not responded adequately to conventional medical treatments such as phosphodiesterase type-5 (PDE-5) inhibitors. Diabetes mellitus is a major risk factor for erectile dysfunction and is associated with endothelial dysfunction, impaired smooth muscle relaxation, neuropathy, and increased fibrosis within penile tissue. Although many patients respond to standard pharmacological treatments, diabetic patients often demonstrate reduced responsiveness to these therapies. Regenerative medicine approaches, including stem cell therapy and stem cell-derived exosomes, have emerged as potential therapeutic strategies due to their regenerative, angiogenic, neuroprotective, and anti-fibrotic effects. The main questions this study aims to answer are: * Whether intracavernosal administration of mesenchymal stem cells or MSC-derived exosomes improves erectile function, as measured by changes in the International Index of Erectile Function-5 (IIEF-5) and Erectile Hardness Score (EHS). * Whether penile hemodynamics improve following treatment, as assessed by penile Doppler ultrasonography parameters including peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI). Participants will be randomly assigned to one of three groups: * Intracavernosal placebo injection * Intracavernosal injection of umbilical cord-derived mesenchymal stem cells (5×10⁶ cells) * Intracavernosal injection of umbilical cord-derived mesenchymal stem cell-derived exosomes (75 μg) All interventions will be administered as a single intracavernosal injection under controlled clinical conditions. Participants will undergo baseline evaluation including medical history, physical examination, erectile function assessment using the IIEF-5 questionnaire, and penile Doppler ultrasonography. Follow-up evaluations will be conducted at 1, 3, 6, and 12 months after treatment to assess changes in erectile function, penile vascular parameters, and treatment-related adverse events. The study will also monitor potential side effects such as pain, bruising, hematoma, edema, or other complications related to the intracavernosal injection procedure. Participants will be recruited from patients presenting to the urology outpatient clinic with diabetic erectile dysfunction. Eligible participants must have a diagnosis of erectile dysfunction for at least six months, a history of diabetes mellitus for at least five years, and insufficient response to standard medical therapy. Patients with penile anatomical deformities, active infections, malignancy, unstable cardiovascular disease, autoimmune disease, or other contraindications to intracavernosal treatment will be excluded.