Apelin levels in normal pregnancy

Apelin is an adipokine secreted from adipose and other tissues with increased expression in obesity, role in glucose metabolism and atherosclerosis, as well as in oxidative stress. Pregnancy is considered a state of hyperlipidemia, oxidative stress and decreased insulin sensitivity. The aim of the present study is to investigate the levels of apelin in human pregnancy and its relation to insulin sensitivity.

One hundred and six pregnant women (24th-28th week of gestation), aged 27·9 ± 0·4 years, were compared to 106 age-matched healthy, nonpregnant women (controls). Measured parameters included serum levels of glucose, insulin, apelin, adiponectin, total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), triglycerides and oxidized LDL (ox-LDL). The body mass index (BMI) and the quantitative insulin sensitivity check index (QUICKI) were calculated as well.

BMI, serum lipids and insulin levels were significantly higher, whereas serum apelin and glucose levels were lower in the pregnancy group compared to the control group. There was a significant negative correlation between apelin and adiponectin, in both groups. Additionally, apelin was negatively correlated with ox-LDL and HDL-cholesterol in the pregnancy group.

Although strongly correlated with adiponectin, apelin cannot be used as a marker of insulin sensitivity, but it could serve as a marker of oxidative stress in pregnancy.