title: Immunolocalization of tissue plasminogen activator in the diabetic and nondiabetic retina and choroid.
abstract: Retinal capillary closure is a common finding in many patients with diabetic retinopathy. The cause of this capillary occlusion is unknown. Since occlusions in microthromboembolic disease can occur because of deficiencies in tissue plasminogen activator (tPA) and since systemic tPA decreases with an increasing duration of diabetes mellitus, the immunohistochemical localization of tPA in the retinas and choroids of diabetic and nondiabetic patients was investigated. The localization of tPA was confined to arteries and arterioles in peripheral retinas from nondiabetics. Both veins and arteries were positive in these choroids. Two of three noninsulin-dependent diabetics had normal levels of immunoreactivity in their retinas, and all had normal levels of immunolocalization in their choroids. All but 2 of the 12 insulin-dependent diabetic eyes (IDDM), however, had reduced levels of retinal tPA immunoreactivity which was most pronounced in their peripheral retinas. Seven eyes from patients with IDDM had no reaction product in their peripheral retinas. Two such eyes also had reduced tPA immunoreactivity in their choroidal vessels. Some tPA-positive vessels were observed in the central retinas of these eyes, but the number of positive vessels and amount of reaction product was greatly reduced compared with eyes from nondiabetic patients. These observations suggest that IDDM patients have reduced fibrinolytic activity in their retinas, which might predispose them to thromboembolic disease.
authors.affiliation: Wilmer Ophthalmologic Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: G A
authors.initials: GA
authors.lastname: Lutty
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: C
authors.initials: C
authors.lastname: Chandler
authors.forename: D S
authors.initials: DS
authors.lastname: McLeod
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001160:Arterioles / Q000737:chemistry; D001808:Blood Vessels / Q000737:chemistry; D002648:Child; D002829:Choroid / Q000098:blood supply / Q000737:chemistry*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000737:chemistry; D005169:Factor VIII / Q000737:chemistry; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000737:chemistry*; D012161:Retinal Artery / Q000737:chemistry; D010959:Tissue Plasminogen Activator / Q000032:analysis*
chemical_list: D005169:Factor VIII; D010959:Tissue Plasminogen Activator