Decreased plasma endothelin-1 levels in asymptomatic type I diabetic patients with regional cerebral hypoperfusion assessed by SPECT

The prevalence of stroke is increased in diabetic patients. The vasoconstri ctor peptide endothelin-1 (ET-1) has been implicated in the development of cerebral vasospasm after stroke but its role in the physiological regulatio n of cerebral blood flow (CBF) is not well known. Our aim was to assess the relationship between CBF and plasma ET-1 levels in type I diabetic patient s. Regional CBF was assessed semi-quantitatively by Tc-99(m)-hexamethylprop ylene-amine-oxime (Tc-99(m)-HMPAO) single photon emission computed tomograp hy (SPECT) in 50 cerebral "regions of interest" (ROIs) of 19 type I diabeti c patients without clinical evidence of cerebral disease, and 10 healthy co ntrol subjects. In both groups, plasma ET-1 levels were measured. Results s howed that type I diabetic patients had significantly more hypoperfusion RO Is than control subjects. While up to 68.4% of the type I diabetic patients showed 3 or more hypoperfusion ROIs, only 10% of the control subjects did. Plasma ET-1 levels were lower in the type I diabetes subgroup with 3 or mo re hypoperfusion ROIs than in the type I diabetes subgroup with less than 3 hypoperfusion ROIs and in the control group. Moreover, an inverse correlat ion between the number of hypoperfusion ROIs and plasma ET-1 levels (r = 0. 47, p = 0.04) was found in the type I diabetes group. It is concluded that plasma ET-1 is decreased in type I diabetic patients with subclinical abnor malities of regional CBF assessed by cerebral SPECT. This fact may reflect a compensatory response to the reduction of the brain perfusion in order to prevent ischemic events in these patients. (C) 2000 Elsevier Science Inc.