Evidence for breaches of the retinal vasculature in acquired immune deficiency syndrome angiopathy - A fluorescent microsphere study

Purpose: The author studied the retinal vasculature in patients with acquired immune deficiency syndrome (AIDS) by infusion of microspheres impregnated with fluorescent dye. Methods: Experimental study of the structural integrity of the retinal microvasculature in 14 autopsy patients with AIDS was compared with age- and gender-matched control retinas. Materials: Fourteen autopsy eyes from patients with AIDS, eight autopsy eyes from immunosuppressed control patients, and four autopsy eyes from nonimmunosuppressed control patients were studied. Experimental Method: The central retinal arteries of autopsy eyes were perfused with fluorescent microspheres of 10 and 200 nm in diameter. The retinas were dissected from the eyes and viewed by fluorescence microscopy. Results: Vascular breaches permeable to 200-nm microspheres were discovered in eyes from patients with AIDS. Ruptured microaneurysms were identified at the center of retinal hemorrhages in 7 of 14 eyes from patients with AIDS and 5 of 8 immunosuppressed control eyes. Leakage around microaneurysms occurred even in the absence of hemorrhage and were more frequent in eyes from patients with AIDS (11/14) than in control eyes (3/12). Cotton wool patches were surrounded by tortuous retinal vessels and microaneurysms. Conclusions: Ruptured microaneurysms are a frequent cause of retinal hemorrhage in immunosuppressed patients. Breaches in microaneurysms occur even in the absence of hemorrhage. These breaches are often at least 200 nm in diameter, a size that is permissive to capsids and virions of cytomegalovirus (CMV). Ruptured and/or leaky microaneurysms are potential sources of CMV permeation of the blood-retinal barrier. Breaches of the retinal microvasculature are not specific to patients with AIDS and occur frequently in other immunosuppressed patients.