Mesenchymal stem/stromal cells protect the ocular surface by suppressing inflammation in an experimental dry eye

Dry eye syndrome (DES) is one of the most common ocular diseases affecting nearly 10% of the US population. Most of the currently available treatments are palliative, and few therapeutic agents target biological pathway of DES. Although DES is a multifactorial disease, it is well-known that inflammation in the ocular surface plays an important role in the pathogenesis of DES. Mesenchymal stem/stromal cells (MSCs) have been shown to repair tissues by modulating excessive immune responses in various diseases. Therefore, we here investigated the therapeutic potential of MSCs in a murine model of an inflammation-mediated dry eye that was induced by an intraorbital injection of concanavalin A. We found that a periorbital administration of MSCs reduced the infiltration of CD4(+) T cells and the levels of inflammatory cytokines in the intraorbital gland and ocular surface. Also, MSCs significantly increased aqueous tear production and the number of conjunctival goblet cells. Subsequently, corneal epithelial integrity was well-preserved by MSCs. Together, the results demonstrate that MSCs protect the ocular surface by suppressing inflammation in DES, and suggest that MSCs may offer a therapy for a number of ocular surface diseases where inflammation plays a key role.