Abstract 17096: Enhanced Coronary Arteriolar Reactivity to Vasopressin in Diabetic Patients After Cardiac Surgery
Introduction: Cardioplegic arrest and cardiopulmonary bypass (CP/CPB) are associated with vasomotor dysfunction of coronary arterioles in diabetic patients undergoing cardiac surgery.
Hypothesis: Diabetes may up-regulate vasopressin receptor expression and alter contractile response of coronary arterioles to vasopressin in the setting of CP/CPB.
Methods: The right atrial tissue samples of diabetic (DM) and non-diabetic (ND) patients (n = 8/group) undergoing cardiac surgery were harvested before and after CP/CPB. The isolated coronary arterioles (80-150μm) dissected from the harvested right atrial tissue samples, were cannulated and pressurized. The changes in diameter were measured with video microscopy. The protein expression/localization of vasopressin receptors (V1A) and 1B (V1B) in the atrial tissue were measured by immune-blotting and immunohistochemistry.
Results: The pre-CP/CPB contractile responses of the coronary arterioles to vasopressin were significantly increased post-CP/CPB in ND and DM and this effect was more pronounced in the DM vessels than that of ND (P<0.05 Figure). Vasopressin-induced contractile response of the coronary arterioles was inhibited in the presence of the specific V1 antagonist SR 49059 (10-7M) in both ND and DM vessels (P<0.05). The post-CP/CPB protein levels of V1A and V1B were significantly increased compared with pre-CP/CPB values in both ND and DM groups (P<0.05), whereas, this increase was higher in DM than that of ND (P<0.05). Immunohistochemistry staining further indicates that V1B receptors were mainly expressed in the myocardium, but not in vascular smooth muscles.
Conclusions: CP/CPB and diabetes are associated with up-regulation in V1 receptor expression/localization in human myocardium. Vasopressin may induce coronary arteriolar constriction via V1A receptors. This alteration may lead to increased coronary arteriolar spasm in diabetic patients undergoing CP/CPB and cardiac surgery.
Author Disclosures: N. Sellke: None. I. Lawandy: None. A. Ehsan: None. Y. Liu: None. F.W. Sellke: None. J. Feng: None.
- © 2016 by American Heart Association, Inc.