ULTRASTRUCTURAL SIMILARITIES BETWEEN RETINAL CAPILLARY PERICYTES AND TRABECULAR CELLS IN NONGLAUCOMATOUS HUMAN EYES

Comparative ultrastructural studies of retinal capillary pericytes and trabecular cells were performed on twelve nonglaucomatous human eyes. Retinal capillary pericytes and trabecular cells were found to have two ultrastructural characteristics in common: they both contain rough endoplasmic reticulum, free ribosomes, Golgi complexes and lysosomes serving the metabolism of their extracellular matrices, and they both have a bundle of microfilaments with focal densities along their course that takes part in the mechanism of cell contraction. Both the trabecular cells and the capillary pericytes were seen to be incorporated in their extracellular matrix and to have primary importance in the metabolism and distribution of this matrix. These findings, that similar cells are located at the strategic position of outflow regulation and neuroretinal perfusion may subserve to a new pathophysiologic approach for understanding correlations of ocular hydrodynamics and hemodynamics in normal conditions and disease states.