ABSTRACT
Objective:To construct a porcine model of ischemia with non-obstructive coronary artery (INOCA) and explore the diagnostic value of a one-stop noninvasive method including CT myocardial perfusion imaging (CT-MPI) and coronary CT angiography (CCTA).Methods:Twelve swines were divided into the experimental group (9) and the normal group (3). Coronary microvascular dysfunction (CMD) porcine model was constructed in the experimental group by inducing diabetes mellitus, chronic kidney disease, and hypercholesterolemia. Invasive coronary angiography (ICA) and functional examination were performed on all 7+3 trial swines to clarify the INOCA diagnosis after completion of the modeling. Then, CT-MPI and CCTA were performed on all individuals to explore the CT-MPI and CCTA characteristics of INOCA porcine models. CT-MPI parameters, including myocardial blood flow (MBF), and myocardial blood volume (MBV) in rest and stress conditions, and CCTA parameters, including severity of stenosis and CAD-RADS, were analyzed.Results:ICA and functional tests showed that all swines in the experimental group met the diagnostic criteria for INOCA, which meant that INOCA porcine model was constructed successfully. CCTA results confirmed that there was no obstructive coronary stenosis in all 10 swines which were examined, which was consistent with ICA findings. CT-MPI results demonstrated that the mean MBF values, as well as the mean MBV values, in the rest and stress condition of each swines in the experimental group were lower than those of the control group. In contrast to the control group, the mean MBF and MBV values of swines in the experimental group in stress condition were generally lower than those in resting condition.Conclusions:In this study, a porcine model of CMD is successfully constructed by inducing hypercholesterolemia+diabetes mellitus+chronic kidney disease. ICA and invasive functional tests show that this CMD model meet the diagnostic criteria for INOCA. It has been confirmed that one-stop CT multimodality examination including CT-MPI and CCTA can be used for the diagnosis of INOCA as a noninvasive diagnostic method.
ABSTRACT
To investigate the relaxation effect and underlying mechanism of U50,488H (a selective kappa-opioid receptor agonist) on aorta in the rat, isolated aortic ring was perfused and the tension of the vessel was measured. It was shown: (1) kappa-opioid receptor stimulation with U50,488H relaxed rat aorta dose-dependently; (2) the relaxation effect of U50,488H on aorta was partially endothelium-dependent; (3) the relaxation effect of U50,488H was significantly attenuated in the presence of glybenclamide and glipizide, two ATP-sensitive K(+) channel (K(ATP)) blockers; and (4) the relaxation effect of U50,488H on vessel bore no relationship to muscarinic-receptor, beta-adrenoceptor, prostaglandin and nitric oxide (NO). These results indicate that kappa-opioid receptor stimulation with U50,488H relaxes the aortic artery at least partially via K(ATP) channel in the rat.