Overview

Dr. Morrison’s research interests include the study of the development of retinopathy of prematurity (ROP), a blinding disease of the eye. When a child is born prematurely, the normal blood vessels in the eye are immature as well. Due to a complex process involving oxygen saturation and growth factors, the vessels in the eye can grow abnormally leading to blindness. It has been demonstrated that vascular endothelial growth factor (VEGF) is necessary and sufficient for the production of normal blood vessels and pathologic vessels associated with ROP. Insulin-like growth factor (IGF) has also been demonstrated to be associated with this condition and can be used as a serum marker in premature infants for the development of severe ROP in the future. Dr. Morrison currently holds two grants in the study of basic mechanisms of ROP production.

Investigations

The Knights Templar Eye Foundation grant was awarded in 2007. The purpose of this work is to study the effects of IGF on VEGF production in cultured retinal cells. IGF is known to increase VEGF production in retinal astrocytes and retinal pigment epithelial cells. Several splice variants of VEGF are present and have differing degrees of solubility or cell-association. The amount of cell–associated VEGF may vary in retinal cells responsible for normal vascular development versus pathologic angiogenesis under the influence of IGF. This study will elucidate the presence of VEGF isoforms in several retinal cell types responsible for the development of ROP. Photos below depict retinal microvascular endothelial cells and Muller cells in culture used to conduct these studies.

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The International Retinal Research Foundation supports a study on IGF in the developing retina. The effects of IGF on VEGF production in normal vasculogenesis and ROP are poorly understood. Further, the effects of IGF are mitigated by several IGF binding proteins (IGFBP) that also have physiologic effects independent of IGF. This work is a survey of IGF and IGFBP production in the developing retina and in isolated retinal cell cultures. The ultimate goal of this work is to identify new therapeutic targets to interrupt the development of abnormal blood vessels associated with ROP. Currently, retinal injections of IGFBPs are being investigated to attempt to decrease retinal angiogenesis.

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