Correlation between circadian blood pressure rhythm, VCAM-1 serum level, and urinary VCAM-1 excretion in preeclampsia

Objective: Elevated levels of the vascular cell adhesion molecule-1 (VCAM-1 ) in women with preeclampsia may reflect endothelial damage and leukocyte a ctivation. Urinary VCAM-1 excretion in normal pregnancies and those complic ated by hypertension has not been studied. We studied the circadian pattern of VCAM-1 levels in the serum and urinary excretion of VCAM-1 in normal pr egnancies and those complicated by hypertension and analyzed their relation with maternal blood pressure. Methods: Serum and urine samples were obtained at 1-hour and 2-hour interva ls, respectively, over a 24-hour period from 10 normotensive and 10 hyperte nsive pregnant women. VCAM-1 levels were measured by ELISA. Blood pressure was recorded continuously over the 24-hour period. Results: Serum VCAM-1 levels and urinary VCAM-1 excretion were significantl y higher in the hypertensive patients than in the controls (851 vs. 659 ng/ ml and 62.0 vs. 29.4 pg/min, respectively; P < 0.01). Serum VCAM-1 levels d id not show a circadian pattern. In contrast, urinary excretion of VCAM-1 s howed a circadian pattern in both groups with a maximum in the daytime hour s. There was no correlation with circadian blood pressure variations. Conclusion: Urinary excretion of VCAM-1 shows a circadian pattern in both n ormotensive and hypertensive pregnancies. Urinary excretion is independent of the serum levels of VCAM-1, which remain stable, and of blood pressure. This suggests intrinsic renal endothelial dysfunction in pregnancies compli cated by preeclampsia.