Circulating Interleukin-6 (IL-6) Associate with Aortic Dimensions in Genetic Aortic Conditions

Background: Biomarkers that reflect progression of dilatation of the aorta in patients with aortic conditions are needed as surrogate tools to assist in monitoring the condition in a non-invasive manner in combination with imaging procedures but are yet to be established. This study aimed to establish clinically useful biomarkers for aortic conditions in patients enrolled in the Genetically-Triggered Thoracic Aortic Conditions (GenTAC) registry. Methods: Plasma samples of 159 patients enrolled in the GenTAC registry were assessed for circulating biomarkers (interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP1), tissue inhibitor of metalloproteinase-2 (TIMP-2) and transforming growth factor-β1 (TGF β1)] by enzyme-linked immunosorbent assay. Primary diagnosis and aortic image data were compared with the measured values. Results: IL-6 showed significant positive correlations with aortic dimensions at each segment of the aorta, the correlation becoming stronger as it shifts to distal (ascending aorta R=0.26 p=0.004, proximal arch R=0.35 p<0.0001, transverse arch R=0.30 p=0.0005, mid-descending thoracic aorta R=0.40 p<0.0001, thoracoabdominal aorta R=0.38 p<0.0001, suprarenal abdominal aorta R=0.42 p<0.0001, and infrarenal aorta R=0.43 p<0.0001). TIMP-1 also showed a significant correlation albeit weaker, also exhibiting stronger correlation towards the distal end. Conclusion: Circulating IL-6 and TIMP-1 were associated with aortic dimensions in the aortopathies as registered in the GenTAC cohort. Our results provide support that IL-6 and TIMP-1 are associated with aortic aneurysm formation in patients with genetically-triggered thoracic aortic conditions.