[Positive rate of autoantibodies against adrenergic receptors beta1 and angiotensin II type 1 receptors in the type 2 diabetes mellitus with or without hypertension].

Objective: To observe the positive rates of autoantibodies against beta1 adrenergic receptors (beta1-receptor) and angiotensin II type 1 receptors (AT(1)-receptor) in type 2 diabetes patients with or without hypertension.
Methods: The epitopes of the second extracellular loop of beta1-receptor (197 - 222) and AT(1) receptor (165 - 191) were synthesized and serum autoantibodies were determined in type 2 diabetes patients with hypertension (n = 171) or without hypertension (n = 106). Left ventricular dimension was determined by echocardiography. The 24-hour urinary protein was measured by ELISA. The risk factors for enlarged left ventricle were analyzed by multiple logistic regressions.
Results: The positive rates of the autoantibodies against beta1-receptors (45.0%) and AT(1)-receptor (46.2%) in patients with type 2 diabetes with hypertension were significantly higher than those in patients with type 2 diabetes without hypertension (16.0% and 10.4%, respectively, all P < 0.01). In type 2 diabetes patients with hypertension and enlarged left ventricle, the positive rates of the autoantibodies against beta1-receptor 61.4% (35/57) and against AT(1)-receptor 64.9% (37/57)were significantly higher than those in type 2 diabetes patients with normal left ventricular dimension (36.8%, 42/114 and 36.8%, 42/114, respectively, all P < 0.01). Regression analysis demonstrated that course of disease, systolic pressure, serum autoantibodies against beta1 adrenergic receptor and angiotensin II type 1 receptors sera autoantibodies were independent risk factors for left ventricular enlargement (all P < 0.05).
Conclusion: The serum beta1 and AT(1)-receptor autoantibodies are related to enlarged left ventricle in type 2 diabetes patients with hypertension and suggest that autoantibodies against beta1 and AT(1)-receptor might play important roles in the pathogenesis of type 2 diabetes patients with hypertension and enlarged left ventricle.