Plasma levels of endothelin-1 in diabetic retinopathy in pregnancy

Purpose Raised circulating levels of the potent vasoconstrictor endothelin- 1 (ET-1) have been demonstrated in diabetes and pregnancy-induced hypertens ion. Pregnant women with diabetic retinopathy are known to be at a higher r isk of developing pregnancy-induced hypertension than those without retinop athy. To examine the association between ET-1, pregnancy, diabetes and diab etic retinopathy, circulating ET-1 levels were measured in each trimester i n a cohort of women with and without diabetes during pregnancy. Methods A cohort of women with diabetes (n = 13) and normal controls (n = 8 ) were followed throughout pregnancy. Detailed clinical and fundoscopic exa minations were carried out according to ETDRS protocols. Plasma ET-1 levels were measured in each trimester using a sensitive radioimmunoassay. Those with diabetes were further divided into those with retinopathy (n = 7) and those without (n = 6). Results Plasma levels of ET-1 increased progressively during normal pregnan cy and peaked in the third trimester. Women with diabetes had significantly higher levels of plasma ET-1 (14.0 vs 4.6 pg/ml in the first trimester, 14 .0 vs 4.8 pg/ml in the second trimester and 15.8 vs 7.2 pg/ml in the third trimester) compared with those without diabetes. There were no significant differences in plasma ET-1 levels between women with diabetes who had pre-e xisting diabetic retinopathy and those without. Conclusion This study has shown that ET-1 levels rise during normal pregnan cy, and are higher in women with diabetes, which may reflect pre-existing e ndothelial damage. Although no association could be demonstrated between di abetic retinopathy and serum ET-1 levels, this may reflect the small sample size in this study.