Association between Intestinal Escherichia coli Colonization and Endothelial Dysfunction Biomarkers in Apparently Healthy Adults

Abstract

The role of microbiome changes as potential contributors of systemic inflammation and oxidative stress has become increasingly apparent. One Gram-negative bacterium found in the intestines is Escherichia coli. E. coli colonization may also be linked to elevated lipopolysaccharide levels, which cause endothelial dysfunction. via inflammation and oxidative mechanisms. It is unclear whether there is any link between colonization by intestinal E. coli and endothelial dysfunction in healthy individuals. The current study attempted to examine the relationship between the presence of intestinal colonization of E. coli with the biomarkers of endothelial dysfunction in apparently healthy adults, as well as the possible role played by endotoxemia, inflammation, oxidative stress, and metabolism alteration in this correlation. A cross-sectional study was carried out among 150 apparently healthy individuals aged 20–60 years old in Kirkuk Province, Iraq. The participants were divided into a control group (n = 75) and E. coli colonized group (n = 75) according to their culture test results of stool samples. VCAM-1, ICAM-1, ET-1, NO, LPS, hs-CRP, TNF-α, IL-6, MDA, TAC, lipid profile parameters, fasting blood glucose level, insulin level, and HOMA-IR were examined in serum. Correlation and multiple regression analysis were employed in order to determine the factors related to endothelial dysfunction. It was revealed that serum levels of VCAM-1, ICAM-1, ET-1, LPS, hs-CRP, TNF-α, IL-6, MDA, total cholesterol, triglycerides, LDL-C, fasting glucose, insulin, and HOMA-IR were higher significantly in cases of E. coli colonization in the intestines than in the control group (P < 0.05). On the other hand, NO, TAC, and HDL-C levels in the group with colonization were significantly lower. The concentrations of serum LPS had positive correlations significantly with VCAM-1 (r = 0.62), ICAM-1 (r = 0.58), TNF-α (r = 0.66), IL-6 (r = 0.61), and MDA (r = 0.55) whereas there was a significant negative correlation between serum LPS and NO (r = −0.59) (P < 0.001). It was revealed by multiple regression analysis that the serum LPS and TNF-α were independent predictors for endothelial dysfunction. These findings suggest an association between intestinal E. coli colonization and endothelial dysfunction. However, because of the cross-sectional design, no causal relationship can be established.