Cystatin C, beta-2-microglobulin and beta-trace protein in pre-eclampsia.
BACKGROUND
An altered renal function is an essential component of the patho-physiology of pre-eclampsia. The plasma levels of low molecular mass proteins, e.g. beta-trace protein, beta-2-microglobulin and cystatin C, are increased in the third trimester of normal pregnancy. The plasma levels of cystatin C and beta-2-microglobulin are further increased in pre-eclampsia, and the cystatin C level has been reported to be a reliable marker for the disease. The aim of this investigation was to study the plasma levels of beta-trace protein, beta-2-microglobulin and cystatin C in pre-eclampsia, and to determine the diagnostic performance of these proteins compared to that of urate and creatinine.


METHODS
A case-control study of 57 women diagnosed with pre-eclampsia, and 218 healthy women with uncomplicated singleton pregnancies in the third trimester. Women in the catchment area of Lund, Sweden, were included during an 18-month period from October 2003 to April 2005. Venous blood samples were drawn upon inclusion when diagnosis was made. The maternal plasma concentrations of the 3 proteins were analysed by automated particle-enhanced immunoturbidimetric assays.


RESULTS
The plasma levels of the 3 proteins were significantly higher in the third trimester of pre-eclamptic patients compared to healthy pregnant women in the third trimester. The upper reference limits (parametric 97.5 percentile) were 2.57 mg/l for beta-2-microglobulin, 0.72 mg/l for beta-trace protein and 1.37 mg/l for cystatin C. ROC analysis showed similar diagnostic performance for the 3 proteins, with beta-trace protein displaying the best diagnostic performance of all the analytes.


CONCLUSIONS
In this study, the maternal plasma levels of beta2-microglobulin, beta-trace protein and cystatin C were all significantly elevated in pre-eclampsia compared to those of healthy pregnant women, and displayed similar diagnostic performance for diagnosing pre-eclampsia. The results indicate that low molecular mass proteins are useful as markers of renal impairment in pre-eclampsia.
Kristensen
K
K
Department of Obstetrics and Gynaecology, University Hospital, Lund, Sweden. karl.kristensen@gyn.lu.se
Wide-Swensson
D
D
Schmidt
C
C
Blirup-Jensen
S
S
Lindström
V
V
Strevens
H
H
Grubb
A
A
D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D001798:Blood Proteins / Q000378:metabolism*; D016022:Case-Control Studies; D055316:Cystatin C; D015891:Cystatins / Q000097:blood / Q000378:metabolism; D005260:Female; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000097:blood / Q000378:metabolism; D054834:Lipocalins; D011225:Pre-Eclampsia / Q000097:blood / Q000378:metabolism*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012372:ROC Curve; D001613:beta 2-Microglobulin / Q000097:blood / Q000378:metabolism
D015415:Biomarkers; D001798:Blood Proteins; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D054834:Lipocalins; D001613:beta 2-Microglobulin; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase