Transplanted human amniotic epithelial cells express connexin 26 and Na-K-adenosine triphosphatase in the inner ear

Cochlear fibrocytes are the crucial component of the inner ear homeostasis and its defect by various causes; GJB2 (connexin [Cx] 26) mutation, for example, leads to hearing loss. In the present study, we investigated the potential use of human amniotic epithelial cells, proposed to possess pluripotential properties, as a source of transplantation therapy in inner ear disease. The mRNA of the gap junction protein Cx26 and Na-K-adenosine triphosphatase, the immunohistologic expression of these proteins, and the cells' intercellular communication capacity were detected in vitro. Their transplantation into the guinea pig cochlea revealed the survival and expression of the proteins even 3 weeks after transplantation. Transplanted human amniotic epithelial cells were localized at the site where the proteins function, strongly indicating their cooperation in the regional potassium ion recycling. This technology suggests the therapeutic potential for the treatment of hearing loss.