Trapidil decreases the aggregation of platelets from heart transplant recipients ex vivo.

Heart transplant recipients show platelet hyperaggregability, which may be related to the incidence of graft vasculopathy. We investigated whether trapidil can inhibit the aggregation of platelets from these patients. Platelet count, mean platelet volume (MPV), and adenosine diphosphate (ADP)-induced platelet aggregation were determined in 18 heart transplant recipients and 12 healthy subjects. Additionally, platelet-rich plasma from the patients was incubated with trapidil or with saline, prior to measuring ADP-induced aggregation. The MPV was significantly greater in patients compared to controls (9.4+/-1.1 vs 8.5+/-0.7 fL; P=.01), and ADP-induced platelet aggregation was significantly increased in patients compared to controls (81.2%+/-13.1% vs 69.6%+/-16.2%; P=.04, respectively). The trapidil-treated samples showed significantly decreased platelet aggregation compared to the control samples (24.2%+/-12.6% vs 66.7%+/-11.7%; P<.001). Platelets from heart transplant recipients showed an increased MPV and increased ADP-induced aggregation. Trapidil effectively reduced the ADP-induced aggregation ex vivo.

Effects of intramyocardial pVEGF165 delivery on regional myocardial blood flow: evidence for a spatial 'delivery-efficacy' mismatch.

The aim of this study was to determine the effects of direct intramyocardial pVEGF165 gene transfer on regional myocardial blood flow in a porcine model of chronic myocardial ischaemia. Pigs underwent placement of an ameroid constrictor around the left circumflex coronary artery. After 3 weeks, animals received direct intramyocardial injections of pVEGF165 (20 x 50 microl at 1 microg/microl, n=11) or a plasmid vector encoding chloramphenicol acetyltransferase (20 x 50 microl at 1 microg/microl, n=11) into a specified target area (TA) of the left lateral wall. At 3 weeks after gene transfer, animals underwent final evaluation including a systematic assessment of regional myocardial blood flow (MBF) under resting and stress conditions. In all, 20 animals (10 per group) reached final studies. There was no change in mean arterial blood pressure or Rentrop collateral score from gene delivery to final studies in either group, nor were there differences between study groups. MBF was significantly higher in the areas adjacent to the TA in the VEGF group under resting (P<0.001) and stress conditions (P<0.05). In addition, pVEGF165 gene transfer abolished flow differences between the adjacent areas and the septum. MBF was not different between study groups in the TA, the anterior wall, or the septum. In conclusion, direct intramyocardial pVEGF165 gene transfer significantly improves myocardial blood flow. However, this effect is limited to the myocardial segments adjacent to the area of gene delivery. These data, therefore, demonstrate a spatial 'delivery-efficacy' mismatch with implications for myocardial gene delivery sites and detection of treatment effects in vivo.

Antioxidant and antiprotease status in peripheral blood and BAL fluid after cardiopulmonary bypass.

OBJECTIVE: Cardiopulmonary bypass (CPB) triggers systemic inflammation. Recent evidence suggests that metabolic and oxygenation management can affect the outcome of patients after cardiac surgery. We investigated the influence of oxidant/antioxidant and protease/antiprotease imbalance during the course of systemic and pulmonary inflammation. METHODS: In a study of 61 patients, we measured the intracellular thiol concentration, the intracellular activity of cathepsins and elastase, and the concentrations of secreted elastase, soluble alpha(1)-proteinase inhibitor (alpha(1)-PI), and secretory leukoprotease inhibitor (SLPI). Peripheral blood and BAL fluid (BALF) were obtained preoperatively and 2 h after CPB. RESULTS: A post-CPB depletion of thiol was found in blood granulocytes, lymphocytes, and monocytes, as well as BALF lymphocytes and macrophages. The degree of postoperative depletion correlated with PO(2) and blood glucose levels during CPB. Concomitant reduction of FEV(1) showed positive correlation with thiol depletion of blood monocytes and granulocytes. Elastase and cathepsin activities were increased in blood cells but not in lymphocytes or macrophages from BALF. The concentrations of secreted elastase were significantly increased in blood plasma but not in BALF. Enhanced antiprotease (alpha(1)-PI, SLPI) concentrations were measured in BALF but not in peripheral blood. CONCLUSIONS: The inflammatory response of the intra-alveolar compartment is clearly distinguishable from systemic inflammation. CPB causes a differentiated impairment of the antioxidant defense system as well as a protease/antiprotease imbalance in blood and BALF. Oxygenation under circumstances of CPB and concomitant pulmonary disease, as well as blood glucose metabolism, influence the antioxidative defense. Individual perioperative management of blood glucose and oxygenation could improve cellular defense systems in the peripheral blood and BALF and therefore result in a more favorable patient outcome.

[Cardiac gene expression after brief coronary occlusion]. / Kardiale Genexpression nach kurzen Koronarverschläussen.

In the pig short coronary occlusions induce molecular damage on the protein level in the myocardium, which elicit repair mechanisms by increased transcription and translation, including the activation of potential transcription factors (protooncogenes), genes involved in repair processes (heat shock genes) or calcium-binding genes. Additionally, some growth factors like insulin-like growth factor II show increased transcription in accordance with their function as trophic factors for reversibly injured myocardium. Changes in mRNA levels mostly are due to increased transcription rates and rarely due to prolonged half-life of the mRNA. However, at present our data do not allow us to conclude which genes are causative for myocardial stunning and/or ischemic preconditioning.

Enhanced gene expression of calcium regulatory proteins in stunned porcine myocardium.

OBJECTIVE: Increasing evidence points to a molecular disturbance of Ca2+ homeostasis in stunned myocardium. The aim of this study was therefore to investigate the expression of mRNAs for Ca2+ binding proteins related to the sarcoplasmic reticulum in a porcine model of myocardial stunning. METHODS: In 22 anaesthetised pigs, stunning was achieved by one or two cycles of 10 min left anterior descending coronary artery occlusion and reperfusion. Hearts were excised at various timepoints of the protocol. Total RNA was extracted from stunned (experimental) as well as normally perfused (control) myocardium. RESULTS: Northern blot analysis using radioactive cDNA probes revealed that the Ca(2+)-ATPase mRNA levels increased 1.6-fold compared to the control value at 90 min of the second reperfusion. The steady state level of phospholamban mRNA rose 2.5-fold at 180 min of reperfusion. A 2.3-fold increase in calsequestrin mRNAs was observed after 90 min of the second reperfusion. The calmodulin and alpha, beta myosin heavy chain mRNA levels were unchanged. A glyceraldehyde-3-phosphate dehydrogenase cDNA probe served as a reference system. Nuclear run-on assays showed increased transcription for Ca(2+)-ATPase and calsequestrin at 90 min of reperfusion, supporting the view that increased mRNA levels seen with northern hybridisation were due to increased transcription of the respective gene. CONCLUSIONS: The results suggest specific repair mechanisms of stunned myocardium and point to the involvement of calcium regulatory proteins related to the sarcoplasmic reticulum in the pathogenesis of myocardial stunning.