Lower serum levels of IL-13 is associated with increased carotid intima-media thickness in old age subjects

Background Cardiovascular diseases due to atherosclerosis represent the major cause of disability and mortality in old age subjects. The atherosclerotic process is linked to a low grade of systemic inflammation with the involvement of many cytokines and inflammatory proteins. Among them, evidence from animal studies suggests that IL-13 has a protective property. However, the role of IL-13 in the pathogenesis of atherosclerosis in humans is still unknown. Aims With this study, we aim to investigate a potential association between IL-13 and carotid intima-media thickness (IMT) in old age subjects. Methods This is a retrospective study conducted among 79 old age subjects (over 75 years old). All subjects underwent IMT assessment by high-resolution B-mode ultrasonography and IL-13 measurement in serum by ELISA. Results Subjects (41 M/38F) had a mean age of 81.04.5 years and were mostly overweight. Stratifying the whole cohort by IMT thickness (IMT <= 0.9, n=17; IMT >= 1 and <= 1.3, n=50; IMT >= 1.4, n=12) among the main variables explored, only BMI and triglycerides differed among groups, having subjects with higher IMT significantly higher BMI and lower triglycerides. Serum IL-13 levels significantly differed among groups having subjects with IMT >= 1.4 lower levels as compared to other groups (p<0.0001). In all sample population, IMT values significantly correlate with IL-13 levels (r=-0.454, p<0.0001). Indeed, a linear regression analysis showed that independent of age, gender, body mass index, triglycerides, systolic blood pressure, statin use and smoking habit, lower IL-13 serum levels were associated with higher IMT values. Conclusions IL-13, an anti-inflammatory cytokine, may have a protective role in the human atherosclerotic process. It could be used as an effective and promising novel therapeutic target development.