Learning Objectives: Tympanic membrane (TM) perforation, in particular chronic otitis media, is one of the most common clinical problems in the world and can present with sensorineural healing loss. Here, we explored an approach for TM regeneration where the latent progenitor or stem cells within TM epithelial layers may play an important regulatory role. We showed that potential TM stem cells present highly positive staining for epithelial stem cell markers and are present at low levels in all areas of normal TM tissue. Additionally, they are present at high levels in perforated TMs, especially in proximity to the holes, regardless of acute or chronic status, suggesting that TM stem cells may be a potential factor for TM regeneration. Finally, we propose a new therapy using stem cell growth factors for chronic TM regeneration. We developed an insulin-like growth factor-binding protein-releasing chitosan patch to promote TM stem cell growth toward TM regeneration in the chronic TM perforation model. Complete regeneration resulting in an intact TM occurred in 43.8% of chronically perforated animals; healing was dependent on perforation size in that small lesions (<50% area) were resolved in 66.7% of cases. Our study suggests that latent TM stem cells could be potential regulators of regeneration, which provides a new insight into this clinically important process and a potential target for new therapies for chronic otitis media and other eardrum injuries.

Tympanic membrane (TM) perforation, in particular chronic otitis media, is one of the most common clinical problems in the world and can present with sensorineural healing loss. Here, we explored an approach for TM regeneration where the latent progenitor or stem cells within TM epithelial layers may play an important regulatory role. We showed that potential TM stem cells present highly positive staining for epithelial stem cell markers and are present at low levels in all areas of normal TM tissue. Additionally, they are present at high levels in perforated TMs, especially in proximity to the holes, regardless of acute or chronic status, suggesting that TM stem cells may be a potential factor for TM regeneration. Finally, we propose a new therapy using stem cell growth factors for chronic TM regeneration. We developed an insulin-like growth factor-binding protein-releasing chitosan patch to promote TM stem cell growth toward TM regeneration in the chronic TM perforation model. Complete regeneration resulting in an intact TM occurred in 43.8% of chronically perforated animals; healing was dependent on perforation size in that small lesions (<50% area) were resolved in 66.7% of cases. Our study suggests that latent TM stem cells could be potential regulators of regeneration, which provides a new insight into this clinically important process and a potential target for new therapies for chronic otitis media and other eardrum injuries.