Plasma endothelin-1 concentrations in patients with retinal vein occlusions

Abstract

Aims-To investigate whether plasma levels of endothelin-1 (ET-1), a potent vasoconstricting peptide that is crucial in regulating retinal blood flow, were elevated in patients with retinal vein occlusion (RVO). Methods-ET-1 plasma concentrations were determined by radioimmunoassays in a double blind fashion in a group of 18 selected patients with RVO, in 20 healthy age matched non-smoking, normoglycaemic, normotensive control subjects, and in 15 patients with uncomplicated essential hypertension in the same age range. Results-Patients with RVO had significantly increased ET-1 plasma levels (14.22 (SD 4.6) pg/ml) compared with both normal subjects (7.90 (1.6) pg/ml; p < 0.05) and hypertensive patients (8.50 (2.9) pg/ ml; p <0.05). The highest concentrations of circulating ET-1 were found in patients with RVO of the ischaemic type (16.97 (3.5) pg/ml; p < 0.01; n = 7). Systemic hypertension alone did not account for the observed increase in plasma ET-1 concentrations. Conclusions-These findings raise the possibility that the increased circulating ET-1 levels in patients with RVO may be a marker of the occlusive event, thereby suggesting that ET-1 homeostasis may be relevant to RVO pathogenesis and retinal ischaemic manifestations. (Br J Ophthalmol 1998;82:498-503) Endothelin-1 (ET-1) is a vasoactive peptide produced and released by endothelial cells.

Hematologic abnormalities associated with various types of retinal vein occlusion

“…Iannaccone et al [37] reported significantly increased circulating endothelin-1 plasma levels in patients with RVO compared with healthy controls and patients with essential hypertension in the same age range. Circulating endothelin-1 levels were higher in patients with the ischemic type of RVO (three BRVO and four CRVO) than non-ischemic RVO (six BRVO and five CRVO).…”

Role of Endothelium in Vasomotor Responses to Endothelin System and Protein Kinase C Activation in Porcine Retinal Arterioles

“…The 21 amino acid peptide endothelin-1 (ET-1) is synthesized by retinal arterioles to exert vasoconstriction, predominantly via endothelin type A (ET A ) receptor activation. 2 Elevated vitreous and/or plasma levels of ET-1 are associated with several important retinal diseases, including retinal vein occlusion, 3 open angle glaucoma, 4 and diabetic retinopathy, 5,6 and ET-1 may contribute, in part, to these pathologies through its activity as a vasoconstrictor. On the other hand, ET-1 also can activate endothelial ET type B (ET B ) receptors to exert vasodilation via released nitric oxide (NO).…”

Refractoriness to the Effect of Endothelin-1 in Porcine Ciliary Arteries

“…17,18 This is the reason why an increased level of ET in the circulating blood (as can be observed in many different autoimmune diseases such as multiple sclerosis) has a major effect on optic nerve head circulation but no or only a minimal effect on retinal or brain circulation. An increased level of ET seems to be implicated in the pathogenesis of many ocular diseases, particularly retinal vein occlusion, 19,20 glaucoma, 21 diabetic retinopathy, 22 and giant cell arteritis. 23 Although ET obviously plays an important role, many basic aspects of its function are still poorly understood, including the question of the dose-response relationship.…”