Exploring the Potential of Stem Cells: A Systematic Review on Cellular Therapy for Sensorineural Hearing Loss

Sensorineural hearing loss affects a significant portion of the global population, with its prevalence projected to rise sharply in the coming years. Most cases involve the degeneration of hair cells and spiral ganglion neurons within the inner ear, and current therapeutic options for hearing rehabilitation offer limited efficacy with variable outcomes among patients. This systematic review evaluates the existing evidence on stem cell therapy as an intervention for hearing loss, focusing on its impact on hearing restoration, quality of life, and safety. A thorough search of electronic databases and clinical trial registries identified randomized and quasi-randomized studies on this topic. Eight studies met the inclusion criteria, investigating various types of stem cells such as embryonic, umbilical cord, and inner ear cells administered intravenously or directly into the inner ear. Most studies used animal models to simulate hearing loss, while one was conducted in humans. Findings on hearing improvement were mixed, with some studies reporting significant improvements in hearing thresholds and others showing no effect. The safety of stem cell therapy was assessed in a single human study, which noted no significant adverse effects. While the results indicate potential therapeutic value, further human studies with standardized protocols and larger sample sizes are necessary to clarify the safety and effectiveness of stem cell therapy for sensorineural hearing loss.