cpu0213 and pimagedine

Spatial dispersion of bioactive substances in the myocardium could serve as pathological basis for arrhythmogenesis and cardiac impairment by beta-adrenoceptor stimulation. We hypothesized that dispersed NADPH oxidase, protein kinase Cepsilon (PKCepsilon), early response gene (ERG), and matrix metalloproteinase 9(MMP-9) across the heart by isoproterenol (ISO) medication might be mediated by the endothelin (ET) - ROS pathway. We aimed to verify if ISO induced spatially heterogeneous distribution of pPKCepsilon, NAPDH oxidase, MMP-9 and ERG could be mitigated by either an ET receptor antagonist CPU0213 or iNOS inhibitor aminoguanidine.. Rats were treated with ISO (1 mg/kg sc) for 10 days, and drug interventions (mg/kg) either CPU0213 (30 sc) or aminoguanidine (100 ip) were administered on days 8-10. Expression of NADPH oxidase, MMP-9, ERG, and PKCepsilon in the left and right ventricle (LV, RV) and septum (S) were measured separately.. Ventricular hypertrophy was found in the LV, S, and RV, in association with dispersed QTc and oxidative stress in ISO-treated rats. mRNA and protein expression of MMP-9, PKCepsilon, NADPH oxidase and ERG in the LV, S, and RV were obviously dispersed, with augmented expression mainly in the LV and S. Dispersed parameters were re-harmonized by either CPU0213, or aminoguanidine.. We found at the first time that ISO-induced dispersed distribution of pPKCepsilon, NADPH oxidase, MMP-9, and ERG in the LV, S, and RV of the heart, which were suppressed by either CPU0213 or aminoguanidine. It indicates that the ET-ROS pathway plays a role in the dispersed distribution of bioactive substances following sustained beta-receptor stimulation.

Topics: Animals; Cardiotonic Agents; Endothelin Receptor Antagonists; Gene Expression Regulation; Guanidines; Heart; Hypertrophy; Isoproterenol; Male; Matrix Metalloproteinase 9; Myocardium; NADPH Oxidases; Nitric Oxide Synthase; Protein Kinase C-epsilon; Pyrazoles; Rats; Rats, Sprague-Dawley

An increase in reactive oxygen species (ROS) through NADPH oxidase activation frequently follows stress that activates beta-adrenoreceptors, leading to deterioration of cardiovascular disease. We hypothesized that upregulation of NADPH oxidase in the vasculature causes mild vascular spasm subsequent to chronic isoproterenol (ISO) administration, correlating significantly with activation of both ETA and ETB receptors. We tested whether the dual endothelin receptor antagonist CPU0213 is effective in reversing ISO-induced vascular abnormality by suppressing activated NADPH oxidase in the vasculature. Rats were injected with ISO (1 mg/kg, SC) for 10 days to induce vascular dysfunction and treated with CPU0213 (30 mg/kg, SC) or aminoguanidine (AMG, an inhibitor of iNOS, 100 mg/kg, PO) from day 7 to day 10. On day 11, we found an increase in vascular response to phenylephrine (Phe) and reductions in NO availability and acetylcholine (ACh)-induced relaxation in ISO-treated rats along with upregulated mRNA of ETA, ETB, iNOS, NADPH oxidase-Phox22 and Phox47, and matrix metalloproteinase 9 (MMP9). These abnormalities were attenuated by 3 days of intervention with CPU0213 but less with AMG. CPU0213 was more effective in relieving enhanced vascular constriction and reversal of ET receptor and MMP9 expression in the vasculature than was AMG. In conclusion, an upregulation of NADPH oxidase phox 22 and phox 47, ETA and ETB, and MMP9 correlates with vascular abnormality and the endothelin receptor antagonist CPU0213 was more effective than AMG in reversing ISO-induced enhanced vascular constriction by normalizing the above abnormal expression.

Topics: Animals; Aorta, Thoracic; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Guanidines; In Vitro Techniques; Isoproterenol; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Muscle Contraction; Muscle Relaxation; Muscle, Smooth, Vascular; NADPH Oxidases; Nitric Oxide Synthase Type II; Oxidative Stress; Pyrazoles; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Receptor, Endothelin A; Receptor, Endothelin B; RNA, Messenger; Up-Regulation

1. The aims of the present study were to examine whether: (i) upregulation of the endothelin (ET) pathway is involved in impairment of vascular relaxation and early retinopathy in diabetic rats; and (ii) vascular and retinal abnormalities respond to the total triterpene acid (TTA) isolated from Fructus Corni compared with responses to the novel endothelin receptor antagonist CPU0213 and aminoguanidine (AMG), a special antagonist for advanced glycation end-products (AGE) and inducible nitric oxide synthase (iNOS). 2. Male Sprague-Dawley rats were randomized into five groups, namely a normal control and four diabetic groups, which included an untreated diabetic group and groups treated with AMG (100 mg/kg, i.g.), CPU0213 (30 mg/kg, s.c.) or TTA (50 mg/kg, i.g.). Diabetes was induced by single injection of streptozotocin (60 mg/kg, i.p.) on the 1st day. The mRNA expression of prepro-endothelin-1 (ppET-1), endothelin-converting enzyme (ECE) and iNOS in the thoracic aorta and mRNA for ET(A) receptors and iNOS in the retina were detected by reverse transcription-polymerase chain reaction. Vasorelaxation to acetylcholine (ACh) and functional assessment of nitric oxide (NO) bioavailability was determined in the thoracic aorta. 3. We observed upregulated mRNA expression of iNOS, ppET-1 and ECE in the thoracic aorta and upregulated mRNA for the ET(A) receptor and iNOS in the retina in the untreated diabetic group. Vasodilatation mediated by ACh and NO bioavailability were markedly reduced in the thoracic aorta compared with the normal control group. These abnormalities were essentially reversed by TTA, CPU0213 or AMG, with the exception with that AMG did not modify vasodilatation to ACh. 4. These data suggest that upregulation of gene transcription of the ET system mediates depressed vasorelaxation, NO bioavailability and changes in iNOS and ET(A) receptors that reflect early retinopathy in diabetic rats. Total triterpene acid, in terms of pharmacological properties resembling the endothelin receptor antagonist CPU0213, is effective in normalizing expression of the ET system and iNOS in early diabetic retinopathy and vasculaopathy.

Topics: Animals; Aorta, Thoracic; Aspartic Acid Endopeptidases; Cornus; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Endothelin A Receptor Antagonists; Endothelin-1; Endothelin-Converting Enzymes; Guanidines; Male; Metalloendopeptidases; Nitric Oxide Synthase Type II; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Retina; RNA, Messenger; Thoracic Arteries; Triterpenes; Up-Regulation; Vasodilation