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1.  Preserved Coronary Endothelial Function by Inhibition of δ Protein Kinase C in a Porcine Acute Myocardial Infarction Model 
International journal of cardiology  2008;133(2):256-259.
Background
Previous studies demonstrate impairment of endothelial-dependent vasodilation after ischemia/reperfusion (I/R). Though we have demonstrated that inhibition of δ protein kinase C (δPKC) at reperfusion reduces myocyte damage and improves cardiac function in a porcine acute myocardial infarction (AMI) model, impact of the selective δPKC inhibitor on epicardial coronary endothelial function remains unknown.
Methods
Either δPKC inhibitor (δV1-1, n=5) or saline (n=5) was infused into the left anterior descending artery at the last 1 minute of the 30-minute ischemia by balloon occlusion. In vivo responses to bradykinin (endothelium-dependent vasodilator) or nitroglycerin (endothelium-independent vasodilator) were analyzed at 24 h after I/R using intravascular ultrasound. Vascular responses were calculated as the ratio of vessel area at each time point (30, 60, 90 and 120 seconds after the infusion), divided by values at baseline (before the infusion).
Results
In control pigs, endothelial-dependent vasodilation following bradykinin infusion in infarct-related epicardial coronary artery was impaired, whereas in δPKC inhibitor treated-pigs the endothelial-dependent vasodilation was preserved. Nitroglycerin infusion caused similar vasodilatory responses in the both groups.
Conclusions
This is the first demonstration that a δPKC inhibitor preserves vasodilator capacity in epicardial coronary arteries in an in vivo porcine AMI model. Because endothelial dysfunction correlates with worse outcome in patients with AMI, this preserved endothelial function in epicardial coronary arteries might result in a better clinical outcome.
doi:10.1016/j.ijcard.2007.11.021
PMCID: PMC2688394  PMID: 18242734
ultrasonography; angioplasty; myocardial infarction; protein kinases; endothelium
2.  Mast cells and εPKC: A role in cardiac remodeling in hypertension-induced heart failure 
Heart failure (HF) is a chronic syndrome in which pathological cardiac remodeling is an integral part of the disease and mast cell (MC) degranulation-derived mediators have been suggested to play a role in its progression. Protein kinase C (PKC) signaling is a key event in the signal transduction pathway of MC degranulation. We recently found that inhibition of εPKC slows down the progression of hypertension-induced HF in salt-sensitive Dahl rats fed a high-salt diet. We therefore determined whether εPKC inhibition affects MC degranulation in this model. Six week-old male Dahl rats were fed with a high-salt diet to induce systemic hypertension, which resulted in concentric left ventricular hypertrophy at the age of 11 weeks, followed by myocardial dilatation and HF at the age of 17 weeks. We administered εV1-2 an εPKC-selective inhibitor peptide (3 mg/Kg/day), δV1-1, a δPKC-selective inhibitor peptide (3 mg/Kg/day), TAT (negative control; at equimolar concentration; 1.6 mg/Kg/day) or olmesartan (angiotensin receptor blocker [ARB] as a positive control; 3mg/Kg/day) between 11 weeks and 17 weeks. Treatment with εV1-2 attenuated cardiac MC degranulation without affecting MC density, myocardial fibrosis, microvessel patency, vascular thickening and cardiac inflammation in comparison to TAT- or δV1-1-treatment. Treatment with ARB also attenuated MC degranulation and cardiac remodeling, but to a lesser extent when compared to εV1-2. Finally, εV1-2 treatment inhibited MC degranulation in isolated peritoneal MCs. Together, our data suggest that εPKC inhibition attenuates pathological remodeling in hypertension-induced HF, at least in part, by preventing cardiac MC degranulation.
doi:10.1016/j.yjmcc.2008.08.009
PMCID: PMC2657602  PMID: 18804478
Mast cell degranulation; protein kinase C; PKC-selective inhibitor peptide; cardiac remodeling; heart failure
3.  Impaired perfusion after myocardial infarction is due to reperfusion-induced δPKC-mediated myocardial damage 
Cardiovascular research  2006;73(4):699-709.
Objective
To improve myocardial flow during reperfusion after acute myocardial infarction and to elucidate the molecular and cellular basis that impedes it. According to the AHA/ACC recommendation, an ideal reperfusion treatment in patients with acute myocardial infarction (AMI) should not only focus on restoring flow in the occluded artery, but should aim to reduce microvascular damage to improve blood flow in the infarcted myocardium.
Methods
Transgenic mouse hearts expressing the δPKC (protein kinase C) inhibitor, δV1-1, in their myocytes only were treated with or without the δPKC inhibitor after ischemia in an ex vivo AMI model. δV1-1 or vehicle was also delivered at reperfusion in an in vivo porcine model of AMI. Microvascular dysfunction was assessed by physiological and histological measurements.
Results
δPKC inhibition in the endothelial cells improved myocardial perfusion in the transgenic mice. In the porcine in vivo AMI model, coronary flow reserve (CFR), which is impaired for 6 days following infarction, was improved immediately following a one-minute treatment at the end of the ischemic period with the δPKC-selective inhibitor, δV1-1 (∼250 ng/Kg), and was completely corrected by 24 hrs. Myocardial contrast echocardiography, electron microscopy studies, and TUNEL staining demonstrated δPKC-mediated microvascular damage. δPKC-induced preconditioning, which also reduces infarct size by >60%, did not improve microvascular function.
Conclusions
These data suggest that δPKC activation in the microvasculature impairs blood flow in the infarcted tissue after restoring flow in the occluded artery and that AMI patients with no-reflow may therefore benefit from treatment with a δPKC inhibitor given in conjunction with removal of the coronary occlusion.
doi:10.1016/j.cardiores.2006.12.011
PMCID: PMC2180159  PMID: 17234167
4.  Sustained pharmacological inhibition of δPKC protects against hypertensive encephalopathy through prevention of blood-brain barrier breakdown in rats 
Hypertensive encephalopathy is a potentially fatal condition associated with cerebral edema and the breakdown of the blood-brain barrier (BBB). The molecular pathways leading to this condition, however, are unknown. We determined the role of δPKC, which is thought to regulate microvascular permeability, in the development of hypertensive encephalopathy using δV1-1 — a selective peptide inhibitor of δPKC. As a model of hypertensive encephalopathy, Dahl salt-sensitive rats were fed an 8% high-salt diet from 6 weeks of age and then were infused s.c. with saline, control TAT peptide, or δV1-1 using osmotic minipumps. The mortality rate and the behavioral symptoms of hypertensive encephalopathy decreased significantly in the δV1-1–treated group relative to the control-treated group, and BBB permeability was reduced by more than 60%. Treatment with δV1-1 was also associated with decreased δPKC accumulation in capillary endothelial cells and in the endfeet of capillary astrocytes, which suggests decreased microvasculature disruption. Treatment with δV1-1 prevented hypertension-induced tight junction disruption associated with BBB breakdown, which suggests that δPKC may specifically act to dysregulate tight junction components. Together, these results suggest that δPKC plays a role in the development of hypertension-induced encephalopathy and may be a therapeutic target for the prevention of BBB disruption.
doi:10.1172/JCI32636
PMCID: PMC2147668  PMID: 18097471

Results 1-4 (4)