Abstract
Purpose::
Relative contribution of aldosterone in eye physiopathologies was suggested by identification of mineralocorticoide receptor (MCR) expression in ocular tissues. In this study we report aldosterone synthase (CYP11B2) expression by retinal endothelial cells that implies a putative synthesis of aldosterone by those cells.
Methods::
Experiments were performed on bovine retinal endothelial cells (BREC) and human bone marrow endothelial cells (HBMEC). RT-PCR analysis of CYP11B2, using specific primers 3’-CCACCACCCTGTTCAGCCC-5’and 5’-CAGGAGGAGACC CCATGTG-3’, reveals aldosterone synthase mRNA expression by.both bovine and human cells. Moreover, immunohistochemistry indicates expression of Von Willebrand Factor (VWF), MCR and CYP11B2 by rat and human ocular tissus endothelials cells. Finally, aldosterone implication on angiogenesis and endothelial cells migration was tested using antagonists, aldacton and eplerenon, by MatrigelTM and wound healing assays.
Results::
Endothelial cells identity of BREC and HBMEC was verified by detection of VWF protein. By RT-PCR analysis, expression of both CYP11B2 and MCR were identified. These observations were confirmed by immunohistochemistry on rat and human retinal and iris vascular endothelial cells. Aldosterone antagonists could inhibit endothelial cells migration in a wound healing assay. Aldactone was more potent than eplerenon in most of tests probably because the former derivative is not MCR specific but activates other classes of steroid receptors as well. These results suggest that aldosterone is implicated in functional stability of endothelial cells.
Conclusions::
Expression of aldosteron synthase and mineralocorticoid receptor by retinal vascular endothelium indicates an intraocular generation of aldosterone. Thus, CYP11B2 regulation may have a crucial role in ocular function and its understanding should enable us to control ocular function in normal and pathological eyes.
Keywords: intraocular pressure