Beneficial effects of atorvastatin on myocardial regions with initially low vasodilatory capacity at various stages of coronary artery disease.

PURPOSE: The aim of this study was to analyse non-invasively the regional effect of therapy with an HMG-CoA reductase inhibitor on myocardial blood flow in patients with coronary artery disease (CAD) with special reference to segments with initially substantially impaired vasodilation. METHODS: The study included 26 patients with untreated hypercholesterolaemia. Coronary angiography revealed CAD in nine patients with stenosis >50% and wall irregularities or minimal stenosis <30% in 17 patients. Before and 4.6+/-1.8 months after atorvastatin therapy, ( 13)N-ammonia positron emission tomography (PET) studies were performed at rest and under pharmacological stress. Minimum coronary vascular resistance (MCR) and coronary flow reserve (CFR) were determined. Segments were divided into those with normal or near-normal (MBF during adenosine > or =2.0 ml/min/g) and those with abnormal (MBF<2.0 ml/min/g) vasodilator flow response. In CAD patients, 156 segments were analysed, 85 of which had abnormal MBF; in the non-obstructive group, 59 of 297 segments had abnormal MBF. RESULTS: LDL cholesterol decreased after atorvastatin therapy from 186+/-43 mg/dl to 101+/-26 mg/dl (p<0.001). In normal segments no significant changes in MBF, CFR and MCR were found. However, initially abnormal segments showed significant improvements in MCR (15%, p<0.0001) and MBF during adenosine (30%, p<0.0001) after therapy. CONCLUSION: The improvement in regional coronary vasodilator function after atorvastatin in patients with coronary atherosclerosis may be caused, at least in part, by increased flow-mediated (endothelium-dependent) dilation of the total arteriolar and arterial vascular system. These data further support the concept of non-invasive management of stable CAD by statin therapy and life-style modification guided by PET.

PKC delta-induced activation of MAPK pathway is required for bFGF-stimulated proliferation of coronary smooth muscle cells.

OBJECTIVE: Basic fibroblast growth factor (bFGF)-stimulated proliferation of coronary smooth muscle cells (cSMC) contributes to the pathogenesis of arteriosclerosis and restenosis. However, the molecular mechanisms involved are not fully understood. We have shown previously that protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) are required for the bFGF-stimulated mitogenic process in bovine cSMC. In this study, we determined the PKC isoform(s) involved and investigated their functional role in the bFGF-stimulated signaling and cell cycle progression in human and bovine cSMC. METHODS AND RESULTS: Downregulation of PKC by phorbol 12-myristate 13-acetate (PMA) inhibited bFGF-induced DNA synthesis, the activation of MAPK, and the expression of c-myc, demonstrating the involvement of PMA-sensitive PKC isoforms in growth factor-induced proliferation and the MAPK pathway. The PMA-sensitive classical PKC isoforms alpha, beta, gamma and novel PKC isoforms delta and epsilon were found in human cSMC. Whereas blocking of the classical PKC isoforms had no influence, the suppression of PKC delta by genetic and pharmacological approaches inhibited the bFGF-stimulated c-Raf1-MEK-MAPK-c-myc signaling and DNA synthesis in cSMC. In contrast to PKC epsilon, our results showed that bFGF activated PKC delta by phosphorylation in a time-dependent manner. In addition, inhibition of PKC delta induced a hypophosphorylation of the retinoblastoma protein and suppression of the cyclins D1 and A, demonstrating the importance of PKC delta for bFGF-induced cell cycle progression through the G1 phase in cSMC. CONCLUSIONS: Our results show that PKC delta is required for the bFGF-stimulated c-Raf1-MEK-MAPK-c-myc signaling pathway involved in the proliferation of cSMC. Therefore, it may be an interesting therapeutic target for preventing proliferative vascular disorders.

Influence of single low-density lipoprotein apheresis on the adhesion molecules soluble vascular cellular adhesion molecule-1, soluble intercellular adhesion molecule-1, and P-selectin.

The aim of our study was to investigate the influence of single low-density lipoprotein apheresis (heparin extracorporeal low-density lipoprotein precipitation [HELP]procedure) on plasma concentrations of soluble adhesion molecules (sAMs) such as soluble vascular cellular adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), and P-selectin in patients with familial heterozygous hypercholesterolemia and documented coronary artery disease enrolled in a chronic weekly HELP apheresis. Before HELP apheresis, the mean plasma concentration of sVCAM-1 was 515 +/- 119 ng/ml, 204 +/- 58 ng/ml for sICAM-1, and 112 +/- 45 ng/ml for P-selectin. After single HELP apheresis, plasma concentrations of sAM declined significantly by 32 +/- 7%, 18 +/- 15%, and 33 +/- 25% for sVCAM- 1,sICAM-1 and P-selectin, respectively. After a 1 week interval, sAM concentrations rose to approximately the initial values. The concentrations of all sAMs studied were significantly lower in the plasma leaving than entering the filter. Due to filtration, the decline in plasma level of sVCAM-1, sICAM-1, and P-selectin was 62 +/- 19%, 51 +/- 39%, and 67 +/- 22%, respectively. In addition to lipid reduction, single HELP apheresis significantly lowers plasma concentrations of sVCAM-1, sICAM-1, and P-selectin.