Changes in serum levels of leptin, cytokines and lipoprotein in preeclamptic and normotensive pregnant women

The aim of this study was to investigate the changes in serum levels of leptin, cytokines and lipoproteins in women with pre-eclampsia and to evaluate their clinical significance in the pathogenesis of pre-eclampsia. We performed a prospective study involving 45 women with pre-eclampsia in the third trimester of pregnancy and 30 normotensive women in the third trimester of pregnancy. Serum level of leptin was measured by enzyme immunoassay using a Cayman chemical kit, Serum levels of tumor necrosis factor (TNF)-alpha, intertleukin (IL)-1beta, soluble IL-2 receptor (sIL-2R), IL-6 and IL-8 were measured by using a nonradioimmunoassay chemiluminescent method. Serum lipid concentrations were measured by an Abbott Aeroset (USA) autoanalyzer. Serum levels of apolipoprotein (Apo)A-I and ApoB were evaluated by nephelometrics assays. Differences between groups were evaluated with Student's unpaired t test and, when a variable was not normally distributed, the Mann-Whitney U test was used. The relationship between the variable was explored by the Pearson correlation test. Serum levels of leptin, TNF-alpha, IL-1beta, sIL-2R, IL-6 and IL-8 in the preeclamptic women were significantly higher than in normotensive women (p < 0.001). In the pre-eclamptic women serum levels of triglycerides, total cholesterol and low-density lipoprotein (LDL)-cholesterol were significantly increased (p < 0.001), while high-density lipoprotein (HDL)-cholesterol and Apo-A were significantly decreased compared to levels in normotensive pregnant women (p &LT; 0.001). No significant differences were noted between the groups in Apo-β (p &GT; 0.05). Serum levels of TNF-α were significantly correlated with the serum levels of IL-6, IL-8, triglycerides, sIL-2R, Apo-A and hematocrit in pre-eclamptic women (r = 0.418, p &LT; 0.05 - r = 0.389, p &LT; 0.01; r = 0.312, p &LT; 0.05; r 0.318, p &LT; 0.05; r 0.340, p &LT; 0.05 and r = 0.41, p &LT; 0,01, respectively). A negative correlation was seen between serum level of leptin and both IL-1β and Apo-A in pre-eclamptic women (r = 0.44, p &LT; 0.05; r = 0.39, p &LT; 0.05, respectively). Serum levels of IL-6 were also signficantly correlated with the serum levels of HDL-cholesterol, LDL-cholesterol and body mass index (BMI) in preeclamptic women (r = 0.40, p &LT; 0.01; r = 0.568, p &LT; 0. 0 1; r 0. 3 0, p &LT; 0. 05, respectively). In addition, serum level of IL-8 were significantly correlated with the serum levels of HDL-cholesterol, total cholesterol and BMI in pre-eclamptic women (r = 0.368, p &LT; 0.05; r = 0.513, p &LT; 0.01 and r = 0.41, p &LT; 0.01, respectively). We found that the pre-eclampsia associated with increases in serum levels of leptin, TNF-α, cytokines, triglycerides, total cholesterol and LDL-cholesterol was associated with a significant reduction in serum levels of HDL-cholesterol and Apo-A. These association may be due to the abnormal lipid metabolism and immune activation involved in the pathogenesis of this disease.