Biomedical subjects

J André Schmidt-Lucke

Publications and source records attributed to J André Schmidt-Lucke.

3 recordsLinked to original sources

PubMed2005

Soluble vascular endothelial growth factor, soluble VEGF receptor Flt-1 and endothelial function in healthy smokers.

OBJECTIVE: To relate levels of vascular endothelial growth factor (VEGF) and its soluble receptor, sFlt-1, with endothelial function in healthy smokers. METHODS: Plasma levels of VEGF and sFlt-1 were measured by ELISA in 22 healthy smokers and 22 matched healthy non-smoking controls, and compared to flow- (FMD) and acetylcholine-mediated (AMD) vasodilatation (endothelial-dependent) (EDV) and nitroglycerine-mediated (NMD) vasodilatation (endothelial-independent) of lower extremities were measured with plethysmography. RESULTS: Smokers and controls had similar plasma VEGF levels, but sFlt-1 levels were lower in smokers than in controls (p<0.01). AMD was lower in smokers compared to controls (p<0.05), but FMD and NMD levels were similar. Smokers and controls with high AMD (>12 ml/100 ml tissue/min) had significantly lower plasma VEGF levels (p<0.001). An inverse correlation was found in both groups, between VEGF and AMD (smokers: r=-0.6, p<0.01; controls: r=-0.71, p<0.005) and with FMD (smokers: r=-0.56, p<0.05; controls: r=-0.58, p<0.005). There were no significant correlations between sFlt-1 with VEGF levels or endothelial-dependent dilatation. CONCLUSION: In conclusion, healthy smokers demonstrate abnormal AMD, and an inverse correlation between plasma VEGF levels (but not sFlt-1) with indices of endothelial dysfunction (FMD and AMD) exists. VEGF, and not sFlt-1, may be related to the pathogenesis of endothelial dysfunction in healthy smoking individuals.

Adult↗

PubMed2003

Changes of plasma concentrations of soluble vascular cell adhesion molecule-1 and vascular endothelial growth factor after increased perfusion of lower extremities in humans.

Shear stress modulates vascular structure and function through cytoskeletal remodeling and activation of signaling cascades. Elevated vascular endothelial growth factor (VEGF) concentrations are seen in atherosclerotic disease and after active increase of perfusion. Levels of soluble vascular cell adhesion molecule (sVCAM-1) are increased in atherosclerotic disease without strict correlation to disease progression. In vitro, increased shear stress induces a biphasic response of sVCAM-1. No data are available on in vivo downregulation of VEGF or sVCAM-1 in humans. In 24 healthy individuals, vascular function of lower extremities was assessed by plethysmography measuring flow-mediated dilation and through intra-arterial infusion of acetylcholine and nitroglycerine. Ten healthy individuals were challenged with cycle exercise testing. Cytokines were measured from citrate plasma from cubital and femoral vein blood. Plasma concentrations of VEGF and sVCAM-1 correlated with endothelium-dependent dilation. Two hours after acetylcholine-induced shear stress, plasma concentrations of sVCAM-1 levels were reduced by 31% (p <.001) locally and 18% (p <.05) systemically. Nitroglycerine produced similar local and systemic suppression (36% and 34%; p <.0001). Immediately after exercise, concentrations of sVCAM-1 increased with a significant decrease one hour later (-9%; p <.01). VEGF increased after infusion of nitroglycerine (+35%; p <.05) and dropped after 1 h of 30-min exercising (-31%, p <.05). This is the first study to show changes of sVCAM-1 in vivo. Changes of VEGF and sVCAM-1 in humans seem time, magnitude, and substance specific. Short acting suppression of VEGF and SVCAM-1 under physiological conditions may explain exercise-induced vascular protection and the lack of correlation of these cytokines with activity of atherosclerotic disease.

Acetylcholine↗

PubMed2002

Low frequency flowmotion/(vasomotion) during patho-physiological conditions.

The role of low frequency flowmotion in physiological or pathophysiological settings is unclear. We performed various series of experiments in young anesthetized New Zealand white (NZW) rabbits. Many animals exhibited flowmotion during control conditions. However, they very often seemed to be in unstable physiological conditions, and our preset inclusion criteria (as to arterial pressure and blood gases) were frequently not met.Therefore, in a first series, we correlated these systematically with the incidence of flowmotion. Eleven of 35 anesthetized rabbits, subjected to extensive surgery, showed flowmotion with a median frequency of 1.5 cpm and a relative "amplitude" of 32%. Arterial pressure was 10 mmHg lower, bicarbonate, base-excess, and PCO(2) values and relative blood flow were also significantly lower compared to animals not exhibiting flowmotion. In a second series, we tested whether flowmotion could be induced by an isolated metabolic acidosis in animals meeting the inclusion criteria and not showing flowmotion at control. Here, flowmotion was induced in 9/10 cases (p < 0.01) 30 min after the start of an HCl-infusion. In a third study, we related the onset of flowmotion to the pressure/flow autoregulation curve. At locally reduced blood pressure all 23 rabbits exhibited flowmotion (p < 0,00001) in the gastrocnemius and the tenuissimus muscles, with maximum flowmotion at a locally reduced blood pressure of 30 mmHg; the LDF-flux level showing 67% of control flow.These results support the concept that low frequency periodic hemodynamics are a characteristic of pathophysiological conditions like hypoperfusion or acidosis rather than indicating a normal physiological state.

Animals↗