Date of Award

9-18-1998

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Edward C. Carlson

Abstract

The purpose of this study was to examine relationships which may exist between retinal microvascular pericytes and renal glomerular mesangial cells regarding their secretory profiles and their resulting potential functional roles in vivo. The following working hypothesis was proposed: Retinal microvessel pericytes and renal glomerular mesangial cells share common morphological and ultrastructural features, reside in similar extracellular matrix environments in vivo, and express similar secretory profiles of extracellular matrix molecules in vitro.The methodology of the study included cell culture, Western blot analysis of the cell layer and matrix, light microscopic immunocytochemistry, ultrastructural analysis of intact and acellular tissues, and immunohistochemistry of intact and acellular retina and kidney. In an effort to determine the similar secretory activities between pericytes and mesangial cells, immunocytochemical techniques were utilized to assay first through third passage bovine retinal pericytes and similar passages of bovine glomerular mesangial cells. The secretory profile of each cell type was examined at confluence, and the following secretory products were sought: fibronectin, laminin, heparan sulfate proteoglycan, and collagen types I-VI. Immunohistochemical techniques were applied to extracellular matrix components of the intact retina and glomerulus to determine the potential contributions of pericytes and mesangial cells to their respective matrices in vivo. Intact tissues were rendered acellular using a deoxycholate procedure (Carlson et al., 1978) to isolate microvessel glomerular extracellular matrices for further immunohistochemical analyses.The results of the study suggest remarkable similarities between the extracellular matrix components of the pericytic and mesangial matrices in the microvasculature of the bovine retina and glomerulus. Moreover, the secretory capacities of pericytes and mesangial cells as determined by the immunocytochemical studies and Western blot analyses of the cell layer and matrix were nearly identical. The similarities of these in vitro profiles with their respective in vivo extracellular matrix environment suggests that these cell types may be major sources for pericytic matrix and microvessel basement membranes in the retina, and for mesangial matrix and glomerular basement membranes in the kidney. Furthermore, these remarkable similarities in vitro support the working hypothesis and suggest that pericyte/mesangial cell relationships transcend morphological descriptions and include secretory commonalities.

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