Enhancing ear drum repair by tracking endogenous stem cells

Tympanic membrane (ear drum) perforation (TMP) is a highly prevalent clinical problem. TMPs can result from physical trauma, pressure changes and, most commonly, from otitis media (OM). Almost all children will suffer from OM before the age of three, with an estimated 31 million cases of chronic suppurative OM annually. Although the majority of acute TMPs spontaneously heal within 2 weeks, approximately 6% do not heal and become chronic requiring surgery. Such surgery is invasive, and availability can be problematic in some communities with high rates of chronic OM. Simpler and less invasive techniques are, therefore, needed in the clinic. The ability to heal suggests the existence of ear drum stem cells that are activated during injury and contribute to repair the wound. We have identified a population of stem cells in the murine tympanic membrane that can be tracked during repair using transgenic reporter mice. We aim to understand how these cells are impacted by factors that have been linked to the formation of chronic perforations, with the aim of being able to stimulate repair capacity enabling non-invasive repair of chronic injuries. For this we will investigate three factors that have been predicted to lead to chronic perforations: the position of the hole, the size of the hole, and the level of infection.