The Effect of Rho Kinase Inhibitors on In Vitro Human Orbital Preadipocytes

Purpose:To identify the effects of Rho Kinase (ROCK) inhibitor medications on human orbital adipogenesis, fibroblast proliferation, and fibrosis.Methods:Orbital adipose tissue was obtained from patients with Graves' ophthalmopathy (GO) as well as controls (non-GO or normal) after informed consent was done. These tissue samples were cultured and adipogenesis was initiated. Levels of Rho Kinase as well as cellular mediators of orbital inflammation and fibrosis. The same cultures and measurements were then repeated with the use of a ROCK inhibitor (KD025-ROCK2) to assess for changes in adipogenesis as well as markers associated with inflammation and fibrosis.Results:Rho Kinase levels in GO tissue were more highly expressed than in controls. These levels were suppressed with the use of the ROCK inhibitor KD025. There was a dose-dependent reduction in differentiation of orbital adipocytes with the use of KD025. KD025 reduced the levels of fibrosis-related gene expression. Finally, there was a significant reduction of transforming growth factor beta mediated phosphorylation signaling pathways in the KD025-treated GO tissue.Conclusion:This study shows that the ROCK inhibitor, KD025, helps to reduce the expression of ROCK in GO tissue along with reducing orbital adipocyte differentiation as well as cell mediators involved in fibrosis that occurs in GO. Rho Kinase plays a role in the development of adipogenesis and fibrosis in Graves' ophthalmopathy and further research on its inhibition may prove useful in the treatment of the disease.