Severe endothelial injury and subsequent repair in patients after successful cardiopulmonary resuscitation.

INTRODUCTION: Ischemia and reperfusion after cardiopulmonary resuscitation (CPR) induce endothelial activation and systemic inflammatory response, resulting in post-resuscitation disease. In this study we analyzed direct markers of endothelial injury, circulating endothelial cells (CECs) and endothelial microparticles (EMPs), and endothelial progenitor cells (EPCs) as a marker of endothelial repair in patients after CPR. METHODS: First we investigated endothelial injury in 40 patients after CPR, 30 controls with stable coronary artery disease (CAD), and 9 healthy subjects, who were included to measure CECs and EMPs. In a subsequent study, endothelial repair was assessed by EPC measurement in 15 CPR, 9 CAD, and 5 healthy subjects. Blood samples were drawn immediately and 24 hours after ROSC and analyzed by flow cytometry. For all statistical analyses P < 0.05 was considered significant. RESULTS: There was a massive rise in CEC count in resuscitated patients compared to CAD (4,494.1 +/- 1,246 versus 312.7 +/- 41 cells/mL; P < 0.001) and healthy patients (47.5 +/- 3.7 cells/mL; P < 0.0005). Patients after prolonged CPR (>or=30 min) showed elevated CECs compared to those resuscitated for <30 min (6,216.6 +/- 2,057 versus 2,340.9 +/- 703.5 cells/mL; P = 0.13/ns). There was a significant positive correlation of CEC count with duration of CPR (R2= 0.84; P < 0.01). EMPs were higher immediately after CPR compared to controls (31.2 +/- 5.8 versus 19.7 +/- 2.4 events/microL; P = 0.12 (CAD); versus 15.0 +/- 5.2 events/microL; P = 0.07 (healthy)) but did not reach significance until 24 hours after CPR (69.1 +/- 12.4 versus 22.0 +/- 3.0 events/microL; P < 0.005 (CAD); versus 15.4 +/- 4.4 events/microL; P < 0.001 (healthy)). EPCs were significantly elevated in patients on the second day after CPR compared to CAD (1.16 +/- 0.41 versus 0.02 +/- 0.01% of lymphocytes; P < 0.005) and healthy (0.04 +/- 0.01; P < 0.005). CONCLUSIONS: In the present study we provide evidence for a severe endothelial damage after successful CPR. Our results point to an ongoing process of endothelial injury, paralleled by a subsequent endothelial regeneration 24 hours after resuscitation.

Angiotensin II receptor-independent antiinflammatory and antiaggregatory properties of losartan: role of the active metabolite EXP3179.

Angiotensin II (Ang II) type 1 receptor (AT(1)) antagonists such as losartan (LOS) are widely used for the treatment of hypertension and elicit antiinflammatory and antiaggregatory in vitro and in patients, although the underlying mechanism are unclear. Following computer-based molecule similarity, we proposed that on cytochrome-P450 degradation, the LOS metabolite EXP3179 is generated, which shows molecule homology to indomethacin, a cyclooxygenase inhibitor with antiinflammatory and antiaggregatory properties. Subsequently, serum-levels of EXP3179 were determined for 8 hours in patients receiving a single oral dose of 100 mg LOS. High-performance liquid chromatography followed by liquid chromatography-mass spectrometry (GC-MS) [corrected] from serum samples revealed a maximum of 10(-7) mol/L for EXP3179 peaking between 3 to 4 hours. The increase in serum-EXP3179 levels was associated with a significant reduction in platelet aggregation in vivo (-35+/-4%, P<0.001 versus control). EXP3179 generation was investigated in a chemical reaction mimicking the liver cytochrome-P450-dependent LOS-degradation and human endothelial cells were exposed to Ang II or lipopolysaccharides (LPS) in the presence of EXP3179 (10(-7) mol/L). LPS- and Ang II-induced COX-2 transcription was abolished by EXP3179. Moreover, EXP3179 significantly reduced Ang II- and LPS-induced formation of prostaglandin F2alpha as determined by GC-MS [corrected]. Thus, antiinflammatory properties of LOS are mediated via its EXP3179 metabolite by abolishing COX-2 mRNA upregulation and COX-dependent TXA2 and PGF2alpha generation. Serum levels of EXP3179 are detectable in patients in concentrations that exhibit antiinflammatory and antiaggregatory properties in vitro.

Grafting an acellular 3-dimensional collagen scaffold onto a non-transmural infarcted myocardium induces neo-angiogenesis and reduces cardiac remodeling.

BACKGROUND: This study was designed to determine whether tissue engineering could be used to reduce ventricular remodeling in a rat model of non-transmural, non-ST-elevation myocardial infarction. METHODS: We grafted an acellular 3-dimensional (3D) collagen type 1 scaffold (solid porous foam) onto infarcted myocardium in rats. Three weeks after grafting, the scaffold was integrated into the myocardium and retarded cardiac remodeling by reducing left ventricular (LV) dilation. The LV inner and outer diameters, measured at the equator at zero LV pressure, decreased (p < 0.05) from 11,040 +/- 212 to 9,144 +/- 135 microm, and 13,469 +/- 187 to 11,673 +/- 104 microm (N = 12), after scaffold transplantation onto infarcted myocardium. The scaffold also shifted the LV pressure-volume curve to the left toward control and induced neo-angiogenesis (700 +/- 25 vs 75 +/- 11 neo-vessels/cm2, N = 5, p < 0.05). These vessels (75 +/- 11%) ranged in diameter from 25 to 100 microm and connected to the native coronary vasculature. Systemic treatment with granulocyte-colony stimulating factor (G-CSF), 50 microg/kg/day for 5 days immediately after myocardial injury, increased (p < 0.05) neo-vascular density from 700 +/- 25 to 978 +/- 57 neo-vessels/cm2. CONCLUSIONS: A 3D collagen type 1 scaffold grafted onto an injured myocardium induced neo-vessel formation and reduced LV remodeling. Treatment with G-CSF further increased the number of vessels in the myocardium, possibly due to mobilization of bone marrow cells.

Stem cell therapy in ischemic heart disease.

Coronary artery disease (CAD) remains the leading cause of death in the Western world. The high impact of its main sequelae, acute myocardial infarction and congestive heart failure (CHF), on the quality of life of patients and the cost of health care drives the search for new therapies. The recent finding that stem cells contribute to neovascularization and possibly improve cardiac function after myocardial infarction makes stem cell therapy the most highly active research area in cardiology. Although the concept of stem cell therapy may revolutionize heart failure treatment, several obstacles need to be addressed. To name a few: 1) Which patient population should be considered for stem cell therapy? 2) What type of stem cell should be used? 3) What is the best route for cell delivery? 4) What is the optimum number of cells that should be used to achieve functional effects? 5) Is stem cell therapy safer and more effective than conventional therapies? The published studies vary significantly in design, making it difficult to draw conclusions on the efficacy of this treatment. For example, different models of ischemia, species of donors and recipients, techniques of cell delivery, cell types, cell numbers and timing of the experiments have been used. However, these studies highlight the landmark concept that stem cell therapy may play a major role in treating cardiovascular diseases in the near future. It should be noted that stem cell therapy is not limited to the treatment of ischemic cardiac disease. Non-ischemic cardiomyopathy, peripheral vascular disease, and aging may be treated by stem cells. Stem cells could be used as vehicle for gene therapy and eliminate the use of viral vectors. Finally, stem cell therapy may be combined with pharmacological, surgical, and interventional therapy to improve outcome. Here we attempt a systematic overview of the science of stem cells and their effects when transplanted into ischemic myocardium.