Repairing Ear drums using Stem Cells

 Currently, multipotent mesenchymal stem cells (MSCs) are a good therapeutic option for the treatment of TMPs because of their self-renewing, and autocrine and paracrine activities. As there are fewer risks of isolation in the use of MSCs for the treatment of TMPs, they are more advantageous for tissue regeneration

Blood cells, nerve cells, and cardiomyocytes can differentiate from umbilical cord stem cells. Studies have shown that after transplanting stem cells from autologous cord blood, auditory function is restored in children with acquired sensorineural hearing loss

The use of stem cells in cell-based therapy is an emerging concept for the treatment of ear disorders. Tympanic membrane perforation (TMP) and inner ear disorders are some of the most commonly presented otologic disorders that can benefit from advances in cell-based therapy. Studies have already demonstrated that stem cell-based therapy can potentially be an effective treatment modality for acute and chronic TMP. Recent studies have also shown promise in application of cell-based approach to treat inner ear dysfunction. In this perspective, we will discuss the recent advancements regarding the use of cell-based therapy for ear disorders.

The delivery of either MSCs alone or a combination of MSCs with biomaterials and growth factors (GFs) at the ruptured TM sites may enhance the activation of epithelial stem cell markers and increase the migration and proliferation of keratinocytes resulting in faster closure of TMPs. This review focuses on the current strategies used to treat TMPs and the importance of MSCs in TM regeneration. Particularly, we have discussed the synergistic effect of MSCs and scaffolds or GFs or scaffolds/GFs in TM regeneration. Finally, with the advancement of tissue engineering technologies such as 3D and 4D bioprinting, MSCs can be used to design patient-specific scaffolds, which may contain physical and chemical guidance cues to improve the extent and rate of targeted tissue regeneration.

The body’s own regenerative capacity can be stimulated to repair perforations in the eardrum by a simple outpatient procedure, Japanese researchers associated with the Translational Research Center for Medical Innovation have shown. They describe their research into this phenomenon in the TRI publication Principles of Regenerative Medicine.

The eardrum can be perforated by various causes, including sudden pressure changes or puncturing by a sharp object. A perforated eardrum leads to hearing loss, which is a major contributor to dementia, and perforations also make the inner ear susceptible to infection. At least 330 million patients worldwide suffer from chronic infection of the middle ear, which is usually accompanied by a perforated eardrum.

The eardrum, or tympanic membrane, has a natural capacity to regenerate. Simple perforations usually heal by themselves, with the injury provoking nearby stem cells into action. However, in infection and chronic inflammation these cells become dormant. Persistent perforations often require surgical treatment.

Shinichi Kanemaru from Kitano Hospital, Osaka, and other researchers associated with the Translational Research Center for Medical Innovation have developed a new tissue engineering approach. It involves activating dormant stem cells by enlarging the perforation. A gelatin sponge impregnated with basic fibroblast growth factor is trimmed to fit and placed over the hole. Gelatin has an advantage over the flat collagen sheets used in conventional regeneration therapies in that it can cover any perforation regardless of its shape or size. The loosely structured scaffold does not interfere with the expansion and movement of regenerative cells.

The sponge gradually releases the growth factor, which is a therapeutic product already available in Japan, thereby stimulating the regeneration of the middle fibrous layer of the tympanic membrane. It is this middle layer that is often poorly repaired in conventional procedures.

A single-center study of 218 patients showed a tympanic membrane perforation closure rate of 81%, with no more than two treatments needed in 80% of closures. No regeneration occurred in perforations due to burns or radiotherapy, and the researchers believe stem cells may have been absent in these patients. In a multicenter study of 20 patients, 80% of perforations closed within 4 weeks, and all patients exhibited improved hearing.

The researchers say a major advantage of this approach is its convenience compared to conventional surgical procedures, which are usually performed under general anesthesia and require specialized surgical training. In contrast, their therapy took only about 15 minutes and was performed in an outpatient setting. Kanemaru says the therapy can thus be easily applied in developing countries and may be attractive for older patients, who may have given up on treatment and are at risk of dementia.