Few investigators have simultaneously evaluated leptin, soluble leptin receptor (SLR) and leptin gene polymorphisms in preeclampsia cases and controls.We examined these three biomolecular markers in 40 preeclampsia cases and 39 controls.Plasma leptin and SLR concentrations were determined using immunoassays. Genotype for the tetranucleotide
repeat (TTTC)n, polymorphism in the 3′-flanking region of the leptin gene was determined using PCR.Alleles of the polymorphism were characterized by size distributions [short repeats (class I); and long repeats (class II)].Logistic regression was used to calculate odds ratio
s (OR) and 95 % confidence intervals (CI).Leptin concentrations were
higher in our cases than in the controls (53.1±4.7 vs. 17.7±2.4 ng/ml,p<0.05).
SLR concentrations were slightly lower in our patients than in the controls (25.7±1.9 vs. 29.1±1.1 ng/ml, p>0.05). Elevated leptin (≥ 14.5 ng/ml) was associated with a 3.8-fold (CI 1.0-14.4) increased risk; whereas low SLR (< 28.5 ng/ml) was associated with a 6.3-fold (CI 1.7-23.2) increased risk of preeclampsia. The I/II genotype was associated with a 3.8-fold increased risk of preeclampsia (OR=3.8; 95 % CI 0.8-18.0); and the II/II genotype was not observed among our cases (0 % vs. 33 % p<0.001). Larger studies would be needed to confirm and further clarify the relations between functional variants in the leptin gene and preeclampsia risk.
Vascular endothelial growth factor (VEGF), a disulphide-linked homodimeric glycoprotein that is selectively mitogenic for endothelial cells, plays an important role in vasculogenesis and angiogenesis. Preeclampsia, a relatively common complication of pregnancy that is characterized by diffuse endothelial dysfunction possibly secondary to impaired trophoblast invasion of the spiral arteries during implantation, has recently been associated with alterations in maternal serum/plasma concentrations of VEGF, and other related growth factors and their receptors. We examined the relationship of maternal plasma VEGF, sVEGF-R1 and PlGF levels to the risk of preeclampsia among women delivering at Harare Maternity Hospital, Zimbabwe. 131 pregnant women with preeclampsia and 175 controls were included in a case-control study. Maternal plasma concentrations of each biomarker were measured using enzymatic methods. We used logistic regression to calculate odds ratios (OR) and 95 % confidence intervals (CI). Preeclampsia risk was inversely related with quartiles of plasma VEGF (OR: 1.0, 1.0, 0.7, and 0.5, with the lowest quartile as reference; p for trend = 0.06). We noted a strong positive association between preeclampsia risk and sVEGF-R1 concentrations (OR: 1.0, 6.5, 9.7, 31.6, with the first quartile as the referent group; p for trend < 0.001). After adjusting for confounders, we noted that women with sVEGF-R1 concentrations in the highest quartile (≥ 496 pg/ml), as compared with those in the lowest quartile (< 62 pg/ml) had a 31.6-fold increased risk of preeclampsia (OR = 31.6, 95 % CI 7.7-128.9). There was no clear evidence of a linear relation in risk of preeclampsia with PlGF concentrations. In conclusion, plasma VEGF, sVEGF-R1 and PlGF concentrations (measured at delivery) were altered among Zimbabwean women with preeclampsia as compared with normotensive women. Our results are consistent with some, though not all, previous reports. Prospective studies are needed to: 1) identify modifiable determinants of maternal plasma concentrations VEGF, sVEGF-R1, and PlGF; and 2) evaluate the temporal relationship between observed alterations of these biological markers in preeclamptic pregnancies.