Autoantibodies against AT1 Receptor Contribute to Vascular Aging and Endothelial Cell Senescence

Vascular aging predisposes the elderly to the progression of many aging-related vascular disorders and leads to deterioration of cardiovascular diseases (CVD). However, the underlying mechanisms have not been clearly elucidated. Agonistic autoantibodies against angiotensin II type 1 (AT1) receptor (AT1-AAs) have been demonstrated to be pro-inflammatory and contribute to the progression of atherosclerosis. However, the association between AT1-AAs and vascular aging has not been defined. Peripheral arterial disease (PAD) is an acknowledged vascular aging-related disease. In this study, AT1-AAs were detected in the sera of patients with PAD and the positive rate was 44.44% (n=63) vs. 17.46% in non-PAD volunteers (n=63). In addition, case-control analysis showed that AT1-AAs level was positively correlated with PAD. To reveal the causal relationship between AT1-AAs and vascular aging, an AT1-AAs-positive rat model was established by active immunization. The carotid pulse wave velocity was higher, and the aortic endothelium-dependent vasodilatation was attenuated significantly in the immunized rats. Morphological staining showed thickening of the aortic wall. Histological examination showed that levels of the senescent markers were increased in the aortic tissue, mostly located at the endothelium. In addition, purified AT1-AAs-IgGs from both the immunized rats and PAD patients induced premature senescence in cultured human umbilical vein endothelial cells. These effects were significantly blocked by the AT1 receptor blocker. Taken together, our study demonstrates that AT1-AAs contribute to the progression of vascular aging and induce EC senescence through AT1 receptor. AT1-AA is a novel biomarker of vascular aging and aging-related CVD that acts to accelerate EC senescence.