Objective: To investigate if the circulating level of soluble fms-like tyrosine kinase 1 (sFlt-1) and vascular endothelial growth factor (VEGF) correlates with urinary albumin excretion in normal pregnancy.
Study design: Serum specimens and 24h urine collections were requested from normal pregnant women at 28-30 weeks of gestation and the following laboratory tests were performed: serum creatinine, urinary protein, urinary albumin and creatinine clearance. For the present study, 117 normal pregnant women were selected as subjects. Subjects' serum was tested to determine sFlt-1 and VEGF concentrations by ELISA. The correlation between sFlt-1 or VEGF concentrations in the serum and renal laboratory variables were analyzed. Simple regression was used to evaluate the correlations.
Results: A significant association was noted between serum sFlt-1 concentration and urinary albumin excretion (r=0.68; P<.0001). Similarly, a significant association was noted between serum VEGF concentration and urinary albumin excretion (r=-0.39; P<.0001). Other urinary variables showed no correlations with either sFlt-1 or VEGF.
Conclusion: Even in normal pregnancy, albumin excretion is affected by an increase in placentally derived sFlt-1. If the sFlt-1 level is kept within normal range, only glomerular endothelial cells are affected and this phenomenon does not spread to the endothelial cells of a whole body.