Abstract 1563: Alpha1-adrenoceptor Autoantibody from Sera of Patients with Primary Hypertension Induced Vascular Endothelial Cell Injury
Background: Vascular endothelial dysfunction is recognized as a characteristic of patients with primary hypertension, and accumulating evidence demonstrated that immunologic factor play an important role in the pathophysiology of hypertension. Previous study has shown that high level of alpha1-adrenoceptor autoantibody (alpha1-AA) existed in the sera of patients with primary hypertension and induced significant vasoconstrictive effects on arteries from important organs. However, whether alpha1-AA involves in vascular endothelial cell injury in hypertension remains unknown. Therefore, the aim of our present study is to explore the role of alpha1-AA in vascular endothelial cell injury in vitro.
Methods: Alpha1-AA was purified from sera of patients with primary hypertension, and its purification, concentration and titer were detected by SDS-PAGE, BCA assay and ELISA, respectively. LDH release, Caspase-3, 8, 9 activity, apoptosis index (aridine orange and propidium iodide staining, AO/PI staining) and DNA damage (single cell gel electrophoresis assay, SCGE) in cultured HUVEC were examined after administration of alpha1-AA (1 μM) for 24h, respectively.
Results: In alpha1-AA administration group, apoptosis index was significantly higher than that in control group(12.83 ± 1.19 % vs. 2.92 ± 0.57 %, P<0.01), caspase-3(2.67±0.21 nmol/h/mg protein vs. 0.95±0.28 nmol/h/mg protein, P<0.01) and caspase-8 (0.58±0.12 nmol/h/mg protein vs. 0.14±0.06 nmol/h/mg protein, P<0.01) activity were increased consistently, however, no remarkable change in caspase-9 activity; meanwhile, the autoantibody also resulted in more than 2.5-fold increase in LDH release (P<0.01) and higher tail moment value of SCGE (15.42 ± 1.28 in alpha1-AA group vs. 1.59 ± 0.29 in control group, P<0.01) respectively.
Conclusion: Our results indicated that alpha1-AA can induce DNA damage, pro-apoptotic and cytotoxic effect on vascular endothelial cell in vitro, which may contribute to the vascular injury in patients with primary hypertension. The results suggest that production of alpha1-AA is a novel risk factor in hypertensive patients and this auto-antibody may play an important role in the development of hypertension.