apyrase and Retinal-Diseases

This article describes the first retinal histopathologic findings in a patient with Susac's syndrome (SS).. Observational case report.. A 51-year-old white woman diagnosed with SS.. Eyes from a 51-year-old white woman diagnosed with SS were obtained at autopsy. One retina was dissected and processed for adenosine diphosphatase (ADPase) flat embedding. Selected areas were processed further for transmission electron microscopy.. Histopathologic examination using ADPase flat-embedding technique.. There were vaso-occlusive changes in the retinal periphery resulting in small areas of capillary dropout. Cross-sections demonstrated serous filled spaces between the retinal blood vessels and the internal limiting membrane. Lumens adjacent to these spaces appeared compressed and sometimes closed, but without thrombosis. Decreased ADPase activity in some peripheral blood vessels suggested endothelial cell dysfunction and vaso-occlusion. In the optic nerve head, numerous corpora amylacea were observed in the vicinity of capillaries with thickened walls and narrow lumens. Transmission electron microscopy demonstrated thickened and amorphous vascular basal lamina and open endothelial cell junctions in some retinal blood vessels.. The serous deposits with compression of retinal vessel lumens observed histologically probably represent the so-called string of pearls described clinically in SS. Chronic extension of these serous deposits along the vessel wall possibly are the cause of retinal arterial wall plaques as described by Gass and other investigators. In the optic nerve head, corpora amylacea are probably a result of microinfarcts resulting from optic nerve head capillary angiopathy. Accumulation of amorphous material in the basal lamina, loss of viable endothelial cells, and capillary dropout suggest that SS may be an endotheliopathy.

Topics: Apyrase; Female; Humans; Microscopy, Electron, Transmission; Middle Aged; Optic Disk; Optic Nerve Diseases; Retinal Diseases; Retinal Vessels; Susac Syndrome

To examine the sickle cell retina in dual perspective (vascular patterns en bloc and structure in serial sections) to gain new insights into sickle cell retinopathy.. We analyzed the retinas of two patients with sickle cell disease (a 54-year-old patient with hemoglobin SC, heterozygous for the S and C mutation in the beta chain of the globin gene, and a 20-month-old patient with sickle cell anemia [SS], homozygous for the S mutation) using the previously described adenosine diphosphatase flat-embedding technique.. The dual-perspective analysis afforded by our technique revealed that the primary site of occlusions was located at the precapillary level. An unusual neovascular formation, the hairpin loop, was observed in both patients' retinas and appeared to result from recanalization of the wall of an occluded vessel. Many autoinfarcted pre-retinal neovascular formations were observed in the older SC patient. Two patent preretinal formations were studied in detail and their evolution appeared to be influenced by mechanical factors. The vessels appeared to have been extruded from the retina, perhaps owing to hydrostatic pressure secondary to downstream occlusions. Small pigmented lesions consisting of retinal pigment epithelial cells ensheathing channels that resembled autoinfarcted vessels were found in the eye of the SC patient.. This study illustrates unusual morphological features of intraretinal and preretinal neovascularization and of chorioretinal lesions in sickle cell retinopathy and suggests alternative mechanisms for their formation.

Topics: Adult; Anemia, Sickle Cell; Apyrase; Choroid Diseases; Electron Probe Microanalysis; Female; Humans; Infant; Male; Middle Aged; Retinal Artery Occlusion; Retinal Diseases; Retinal Neovascularization; Retinal Vessels; Tissue Embedding