Mesenchymal Stem Cells for Treatment of Delayed-Healing Tympanic Membrane Perforations Using Hyaluronate-based Laminas as a Delivery System: An Animal Model With Histopathologic Study.

Abstract

Bone marrow derived-mesenchymal stem cells (BM-MSCs) improve the healing of chronic tympanic membrane perforations (cTMPs) in an animal model. cTMPs generate significant morbidity and reduced quality of life, usually requiring surgical assistance. With growing interest in alternative therapies, we sought to evaluate the effect of BM-MSC-therapy on the healing of cTMPs. Sixty cTMPs were established in C57Bl/6 mice and randomized into four groups: hyaluronate scaffold as graft plus BM-MSCs (n = 19 ears), scaffold plus cell culture media (n = 16), scaffold plus phosphate-buffered saline (PBS, n = 12), and no intervention (n = 13). Hyaluronate scaffolds with or without BM-MSCs were applied on 8-week perforated eardrums. After a blinded assessment of perforation sizes at baseline and 2 weeks after treatment, mean perforation reduction rates (%) were compared. Histology characterization was then performed. Mean perforation size reduction rates were significantly higher for cTMPs that received scaffolds plus BM-MSCs (Student's t test, p = 0.0207, 12.3% [95% CI: 7.8-16.7]) and scaffolds plus cell culture media (p = 0.0477, 11.3% [95% CI: 4.4-18.2]) when compared with no intervention (4.2% [95% CI: 1.2-7.2]). This was not observed when treating eardrums with scaffolds plus PBS (7.3% [95% CI: 2.7-11.9]). On histology, BM-MSC-treated eardrums demonstrated restoration of the trilaminar configuration and reduced inflammatory changes, while other groups developed tissue architecture disorganization and hypercellular infiltrates surrounding the perforation site. BM-MSCs and cell culture media equivalently increased cTMP healing rates. Cell-based therapy conferred a restoration of the trilaminar configuration of the eardrum with relatively compact and organized fibrous layers.