Injection of Cultured Cells with a ROCK Inhibitor for Bullous Keratopathy.

BACKGROUND: Corneal endothelial cell (CEC) disorders, such as Fuchs's endothelial corneal dystrophy, induce abnormal corneal hydration and result in corneal haziness and vision loss known as bullous keratopathy. We investigated whether injection of cultured human CECs supplemented with a rho-associated protein kinase (ROCK) inhibitor into the anterior chamber could increase CEC density. METHODS: We performed an uncontrolled, single-group study involving 11 persons who had received a diagnosis of bullous keratopathy and had no detectable CECs. Human CECs were cultured from a donor cornea; a total of 1×106 passaged cells were supplemented with a ROCK inhibitor (final volume, 300 µl) and injected into the anterior chamber of the eye that was selected for treatment. After the procedure, patients were placed in a prone position for 3 hours. The primary outcome was restoration of corneal transparency, with a CEC density of more than 500 cells per square millimeter at the central cornea at 24 weeks after cell injection. Secondary outcomes were a corneal thickness of less than 630 µm and an improvement in best corrected visual acuity equivalent to two lines or more on a Landolt C eye chart at 24 weeks after cell injection. RESULTS: At 24 weeks after cell injection, we recorded a CEC density of more than 500 cells per square millimeter (range, 947 to 2833) in 11 of the 11 treated eyes (100%; 95% confidence interval [CI], 72 to 100), of which 10 had a CEC density exceeding 1000 cells per square millimeter. A corneal thickness of less than 630 µm (range, 489 to 640) was attained in 10 of the 11 treated eyes (91%; 95% CI, 59 to 100), and an improvement in best corrected visual acuity of two lines or more was recorded in 9 of the 11 treated eyes (82%; 95% CI, 48 to 98). CONCLUSIONS: Injection of human CECs supplemented with a ROCK inhibitor was followed by an increase in CEC density after 24 weeks in 11 persons with bullous keratopathy. (Funded by the Japan Agency for Medical Research and Development and others; UMIN number, UMIN000012534 .).

Rho kinase inhibitor enables cell-based therapy for corneal endothelial dysfunction.

The corneal endothelium maintains corneal transparency; consequently, its dysfunction causes severe vision loss. Tissue engineering-based therapy, as an alternative to conventional donor corneal transplantation, is anticipated to provide a less invasive and more effective therapeutic modality. We conducted a preclinical study for cell-based therapy in a primate model and demonstrated regeneration of the corneal endothelium following injection of cultured monkey corneal endothelial cells (MCECs) or human CECs (HCECs), in combination with a Rho kinase (ROCK) inhibitor, Y-27632, into the anterior chamber. We also evaluated the safety and efficacy of Good Manufacturing Practice (GMP)-grade HCECs, similar to those planned for use as transplant material for human patients in a clinical trial, and we showed that the corneal endothelium was regenerated without adverse effect. We also showed that CEC engraftment is impaired by limited substrate adhesion, which is due to actomyosin contraction induced by dissociation-induced activation of ROCK/MLC signaling. Inclusion of a ROCK inhibitor improves efficiency of engraftment of CECs and enables cell-based therapy for treating corneal endothelial dysfunction as a clinically relevant therapy.

Corneal endothelial expansion promoted by human bone marrow mesenchymal stem cell-derived conditioned medium.

Healthy corneal endothelium is essential for maintaining corneal clarity, as the damage of corneal endothelial cells and loss of cell count causes severe visual impairment. Corneal transplantation is currently the only therapy for severe corneal disorders. The greatly limited proliferative ability of human corneal endothelial cells (HCECs), even in vitro, has challenged researchers to establish efficient techniques for the cultivating HCECs, a pivotal issue for clinical applications. The aim of this study was to evaluate conditioned medium (CM) obtained from human bone marrow-derived mesenchymal stem cells (MSCs) (MSC-CM) for use as a consistent expansion protocol of HCECs. When HCECs were maintained in the presence of MSC-CM, cell morphology assumed a hexagonal shape similar to corneal endothelial cells in vivo, as opposed to the irregular cell shape observed in control cultures in the absence of MSC-CM. They also maintained the functional protein phenotypes; ZO-1 and Na(+)/K(+)-ATPase were localized at the intercellular adherent junctions and pump proteins of corneal endothelium were accordingly expressed. In comparison to the proliferative potential observed in the control cultures, HCECs maintained in MSC-CM were found to have more than twice as many Ki67-positive cells and a greatly increased incorporation of BrdU into DNA. MSC-CM further facilitated the cell migration of HCECs. Lastly, the mechanism of cell proliferation mediated by MSC-CM was investigated, and phosphorylation of Akt and ERK1/2 was observed in HCECs after exposure to MSC-CM. The inhibitor to PI 3-kinase maintained the level of p27(Kip1) for up to 24 hours and greatly blocked the expression of cyclin D1 and D3 during the early G1 phase, leading to the reduction of cell density. These findings indicate that MSC-CM not only stimulates the proliferation of HCECs by regulating the G1 proteins of the cell cycle but also maintains the characteristic differentiated phenotypes necessary for the endothelial functions.