Is There an Association Between Atherosclerotic Burden, Oxidative Stress, and Gut-Derived Lipopolysaccharides?

Recent studies hypothesized a role of gut microbiota favoring atherosclerosis via an increased oxidative stress, but data in peripheral artery disease (PAD) have not been provided yet. The aim of this study was to assess serum lipopolysaccharide (LPS) as well as oxidative stress in PAD patients and controls (CT). Furthermore, we wanted to analyze the relationship between LPS and the severity of atherosclerosis in the lower limb arteries. Eighty consecutive subjects, including 40 PAD patients and 40 CT were recruited. A cross-sectional study was performed to compare serum LPS, soluble Nox2-derived peptide (sNox2-dp), hydrogen peroxide (H₂O₂), H₂O₂ breakdown activity (HBA) and ankle brachial index (ABI) in these two groups. Serum zonulin was used to assess gut permeability. Compared with CT, PAD patients had significant higher values of LPS, zonulin, sNox2-dp, and H₂O₂; conversely ABI and HBA were significantly lower in PAD patients. LPS serum levels were associated with atherosclerotic burden as depicted by the inverse correlation with ABI. LPS was also associated with oxidative stress as shown by its direct correlation with markers of oxidative stress such as sNox2-dp, serum H₂O₂, and HBA. Finally, we found a significant correlation between LPS and zonulin. A multiple linear regression analysis showed that LPS was significantly associated only with ABI. These findings suggest that LPS is elevated in PAD patients with a close association with the atherosclerotic burden and oxidative stress. The correlation between LPS and zonulin suggests that changes in gut permeability could be a potential trigger of LPS translocation in the peripheral circulation.