Biomedical subjects

Matthias Frick

Publications and source records attributed to Matthias Frick.

22 records · Page 2Linked to original sources

PubMed2002

Association of wall thickness of the brachial artery measured with high-resolution ultrasound with risk factors and coronary artery disease.

Intima-media thickness of the carotid and femoral arteries has been associated with coronary atherosclerosis and its clinical sequelae. The brachial artery (BA) is widely used for the assessment of flow-mediated vasodilation. The aim of this study was to examine whether BA wall thickness (WT) is associated with coronary artery disease (CAD) and risk factors. High-resolution ultrasound (13 MHz) examination of the BA was performed in 179 patients undergoing coronary angiography for the evaluation of chest pain. CAD (> or =30% diameter stenosis in > or =1 major branch) was found in 132 patients, whereas 47 patients had smooth coronary arteries. WT of the posterior BA wall (0.4 +/- 0.05 vs 0.35 +/- 0.06 mm, p <0.001) and wall index (WI) (WT/vessel diameter x 100; 16.1 +/- 0.0 vs 13.8 +/- 0.8, p <0.001) were greater in patients with than without CAD. On univariate analysis, WT and WI correlated with age, presence of CAD, systemic hypertension, maximum coronary diameter stenosis, and baseline diameter. On logistic regression analyses adjusting for age, cholesterol levels, systemic hypertension, smoking, and positive family history, WT (p <0.01) and WI (p = 0.02) remained significantly correlated with the presence of CAD. Thus, BA-WT is independently correlated with the presence of CAD. WT may provide a novel noninvasive marker of atherosclerosis that can be assessed together with flow-mediated vasodilation to yield functional and morphologic information in the same vessel.

Adult↗

PubMed2002

Short- and long-term changes of flow-mediated vasodilation in patients under statin therapy.

BACKGROUND: Flow-mediated vasodilation (FMD) of the brachial artery (BA) has been shown to improve in response to lipid-lowering therapy and other therapeutic interventions, usually within 1 to 2 months. Whether FMD remains improved under therapy in the longer term is unknown. HYPOTHESIS: The aim of this study was to examine the short- and long-term changes of FMD under statin therapy. METHODS: Flow-mediated vasodilation and nitroglycerin-mediated vasodilation (NMD) of the BA were measured with high-resolution ultrasound (13 MHz) at baseline and at 4 and 10 months in 18 consecutively recruited patients with coronary artery disease (CAD), in whom statin therapy was newly established. RESULTS: The decrease of total plasma cholesterol levels after 4 and 10 months of statin therapy (243 +/- 31 vs. 186 +/- 30 vs. 191 +/- 40 mg/dl; p < 0.001) was accompanied by an increase in FMD from 4.4 +/- 3.8% at baseline to 9.6 +/- 2.7% at 4 months and to 9.5 +/- 2.6% at 10 months (p < 0.001). Nitroglycerin-mediated vasodilation showed a trend toward improvement after 4 months (14.6 +/- 7.5 vs. 19.1 +/- 3.6 vs. 19.4 +/- 5.6%; NS). The FMD/NMD ratio also rose significantly after 4 months and remained improved after 10 months of statin therapy (0.31 +/- 0.25 vs. 0.52 +/- 0.16 vs. 0.50 +/- 0.14; p < 0.01). CONCLUSION: Statin therapy is associated with sustained improvement of endothelial function up to 10 months. These data support the utility of FMD for the assessment of vascular function in response to lipid-lowering therapy or other therapeutic interventions in long-term studies.

Adult↗

PubMed2002

Heme oxygenase activity modulates vascular endothelial growth factor synthesis in vascular smooth muscle cells.

Hypoxia, cytokines, and nitric oxide (NO) stimulate the generation of vascular endothelial growth factor (VEGF) and induce heme oxygenase-1 (HO-1) expression in vascular tissue. HO-1 degrades heme to carbon monoxide (CO), iron, and biliverdin, the latter being reduced to bilirubin by biliverdin reductase. In the present study, we investigated the role of HO-1 in the modulation of VEGF synthesis in rat vascular smooth muscle cells (VSMC). In VSMC stimulated with cytokines, inhibition of NO production significantly, but not completely, reduced VEGF release. In contrast, inhibition of HO activity by tin protoporphyrin IX (SnPPIX) totally prevented cytokine-induced increase in VEGF, despite an augmented synthesis of intracellular NO. Stimulation of HO-1 activity by hemin enhanced VEGF production; this effect was abrogated by blockade of the HO pathway. Similarly, VEGF synthesis induced by hypoxia was down-regulated by SnPPIX, but not by inhibitors of NO synthase. To elucidate further a direct involvement of HO-1 in the observed effects, we generated transfected cells that overexpressed the HO-1 gene. Notably, these cells synthesized significantly more VEGF protein than cells transfected with a control gene. Among the products of HO-1, biliverdin and bilirubin showed no effect, whereas iron ions inhibited VEGF synthesis. Exposure of cells to 1% CO resulted in a marked accumulation of VEGF (20-fold increase) over the basal level. Our data indicate that HO-1 activity influences the generation of VEGF in VSMC in both normoxic and hypoxic conditions. As CO and iron, respectively the inducer and the inhibitor of VEGF synthesis, are concomitantly produced during the degradation of heme, these data indicate that HO by-products may differentially modulate VEGF production.

Animals↗

PubMedDate not supplied

Atorvastatin affects several angiogenic mediators in human endothelial cells.

The pleiotropic effects of statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, have been recently extended to the modulation of angiogenesis. Here, to get more insight into the statins action, the authors have investigated the effect of atorvastatin on the expression of several angiogenic and inflammatory genes in human umbilical endothelial cells (HUVECs). Atorvastatin was proangiogenic at the dose of 10 nM, and antiangiogenic at the concentrations of 1 to 10 micro M. Moreover, these higher concentrations inhibited also the proliferation of HUVECs induced by vascular endothelial growth factor (VEGF). Lower doses of atorvastatin did not influence endothelial cell proliferation. Importantly, atorvastatin at the micromolar concentrations diminished the production of interleukin (IL)-8, a proinflammatory and proangiogenic chemokine, and inhibited the synthesis of urokinase plasminogen activator (uPA), a potent proinflammatory mediator. However, it decreased also the expression of plasminogen activator inhibitor-1 (PAI-1) and thrombospondin-1 (TSP-1), the inhibitors of angiogenesis. Atorvastatin stimulated the expression of angiopoietin (Ang)-2 and moderately enhanced the expression of endothelial nitric oxide synthase (eNOS), whereas heme oxygenase-1 (HO-1) was not significantly affected. In conclusion, the present findings points to other angiogenesis-related effects of atorvastatin, which may be of relevance to the beneficial influence of statins in cardiovascular system.

Atorvastatin↗