[Determination of blood cystatin C in pregnant women during labor and in their newborns].
BACKGROUND
Human cystatin C is a basic low molecular mass protein (M(r) = 13,359) freely filtered by the glomerulus and almost completely reabsorbed and catabolized by the proximal tubular cells. In this study, we determined maternal and neonatal serum cystatin C levels both in a group of healthy pregnant women and in their newborns over the first five days of life.


METHODS
Fifty healthy pregnant women, aged from 19 to 40 years, were selected. Newborns (31 males, 19 females) demonstrated the 1-min Apgar score ranging between 8 and 10, and the 5-min between 9 and 10. Their gestational age (GA) ranged between 37 and 43 weeks. Cystatin C was determined by using the cystatin C PET kit (Dako, Milano, Italy). We also determined serum creatinine and urea in all patients by using the Ektachem enzymatic assay (Ortho Diagnostic Division, Milano, Italy).


RESULTS
In pregnant women, serum cystatin C was 1.52 +/- 0.39 mg/L, ranging from 0.69 to 2.30 mg/L. Serum creatinine was 58.9 +/- 11.5 mumol/L, and serum urea was 3.117 +/- 0.729 mmol/L. In newborns, serum cystatin C was at birth 2.29 +/- 0.52 mg/L, ranging from 1.17 to 4.84 mg/L. Subsequently, cystatin C significantly decreased over the first five days of life. Serum creatinine was at birth 80.08 +/- 14.26 mumol/L. By using analysis of variance (ANOVA) we found a statistically significant difference between maternal and neonatal cystatin C (p < 0.001) as well as between maternal and neonatal creatinine (p +/- 0.001). However, no correlation has been demonstrated by simple linear regression between maternal and neonatal cystatin C (r = 0.05), while maternal and neonatal creatinine significantly correlated (r = 0.45).


CONCLUSIONS
Our preliminary findings suggest that cystatin C does not cross the placental barrier. Thus, in the neonate cystatin C serum levels may solely derived from himself.
Plebani
M
M
Servizio di Medicina di Laboratorio, Azienda Ospedaliera di Padova, Italia.
Mussap
M
M
Bertelli
L
L
Moggi
G
G
Ruzzante
N
N
Fanos
V
V
Cataldi
L
L
D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D007743:Labor, Obstetric / Q000097:blood*; D008297:Male; D011247:Pregnancy
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins
Determinazione della cistatina C sierica in gestanti al momento del parto e nei loro neonati.