ABSTRACT
INTRODUCTION: Endotoxin activates innate immunity, decreases insulin sensitivity and is associated with obesity. Recent data indicates that subclinical endotoxemia is associated with inflammation in obese women in late pregnancy. OBJECTIVES: The objective of this study was to quantify circulating endotoxin across pregnancy in lean and obese women, and assess the relationship between endotoxin and markers of inflammation and insulin sensitivity. METHODS: Endotoxin was measured in sterile maternal EDTA plasma samples from 24 lean pregnant women (BMI=22.4±1.9kg/m(2)) and 45 obese pregnant women (BMI= 32.6±2.1kg/m(2)), and 6 non-pregnant women. Samples were collected at 10.5±3.1, 21.3±4.6 and 35.2±2.1weeks gestation. Endotoxin was quantified using the PyroGene Recombinant Factor C endotoxin detection assay from LONZA, inter-assay variability <10%. IL-6, myloperoxidase, uric acid, triglycerides, insulin and glucose were also measured. Statistical analysis was by repeated measures ANOVA and students t-test as appropriate. Correlation analysis was performed using Pearson product moment correlation coefficient. Statistical significance was accepted at p<0.05. RESULTS: Endotoxin was significantly increased in both lean (10.4±5.3EU/ml) and obese (9.1±5.3EU/ml) pregnant women compared to non-pregnant women (4.3±2.6EU/ml, p<0.05). Endotoxin increased significantly across pregnancy in both lean and obese pregnant women (p<0.001), but was not different between these groups (table). Endotoxin was not associated with adiposity, IL-6, myloperoxidase, uric acid, triglycerides or insulin sensitivity as assessed by homeostasis model of insulin resistance (HOMA). Data are mean±SD. Repeated measures ANOVA p<0.001. CONCLUSION: Circulating endotoxin increases significantly during pregnancy, but endotoxin is not associated with markers of systemic inflammation or insulin resistance. Pregnancy may represent a condition of metabolic endotoxemia, however the causes and biologic activity of these increasing levels of endotoxin are unclear.
