Serum cystatin C reflects glomerular endotheliosis in normal, hypertensive and pre-eclamptic pregnancies

Abstract

Objective: To study the correlation between serum cystatin C levels and renal structural changes in normal, hypertensive and pre-eclamptic pregnancy to evaluate it as a marker of the degree of renal involvement in pre-eclampsia.

Design: An observational prospective study.

Setting: University Hospital of Lund, Sweden.

Sample: Thirty-six women with hypertensive disease in pregnancy and 12 healthy pregnant women in the third trimester recruited from maternal health care centres in the catchment area of the hospital.

Methods: Renal biopsy samples were obtained from all participants and the degree of endotheliosis as well as the mean glomerular volume was evaluated by light microscopy in silver methenamin-stained sections. Serum cystatin C levels were measured and correlated to the structural changes.

Main outcome measures: Correlation among degree of glomerular endotheliosis, glomerular volume and serum cystatin C.

Results: Serum cystatin C levels differed between the different degrees of endotheliosis, showing a highly significant increasing linear trend. They also correlated significantly with glomerular volume (r = 0.60, P < 0.001). Mean serum urate and creatinine levels also increased with the degree of endotheliosis, but not above the reference interval for normal term pregnancy, even in pre-eclamptic women.

Conclusion: Serum cystatin C may be used as a marker, not only for impaired renal function, but also for the degree of glomerular endotheliosis and increase in glomerular volume in pregnancy. It may be of value in the monitoring of pregnancies complicated by pre-eclampsia.