Plasma levels of endothelin-1 in diabetic retinopathy in pregnancy.
OBJECTIVE
Raised circulating levels of the potent vasoconstrictor endothelin-1 (ET-1) have been demonstrated in diabetes and pregnancy-induced hypertension. Pregnant women with diabetic retinopathy are known to be at a higher risk of developing pregnancy-induced hypertension than those without retinopathy. To examine the association between ET-1, pregnancy, diabetes and diabetic retinopathy, circulating ET-1 levels were measured in each trimester in 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 examinations 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 pregnancy 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. These were no significant differences in plasma ET-1 levels between women with diabetes who had pre-existing diabetic retinopathy and those without.


CONCLUSIONS
This study has shown that ET-1 levels rise during normal pregnancy, and are higher in women with diabetes, which may reflect pre-existing endothelial damage. Although no association could be demonstrated between diabetic retinopathy and serum ET-1 levels, this may reflect the small sample size in this study.
Best
R M
RM
Department of Ophthalmology, Queen's University of Belfast, Northern Ireland. bestrm@aol.com
Hayes
R
R
Hadden
D R
DR
Chakravarthy
U
U
Archer
D B
DB
D000328:Adult; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D003930:Diabetic Retinopathy / Q000097:blood*; D018450:Disease Progression; D019332:Endothelin-1 / Q000097:blood*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood*; D011863:Radioimmunoassay
D015415:Biomarkers; D019332:Endothelin-1