Pre-Procedural Atorvastatin Mobilizes Endothelial Progenitor Cells: Clues to the Salutary Effects of Statins on Healing of Stented Human Arteries

OBJECTIVES: Recent clinical trials suggest an LDL-independent superiority of intensive statin therapy in reducing target vessel revascularization and peri-procedural myocardial infarctions in patients who undergo percutaneous coronary interventions (PCI). While animal studies demonstrate that statins mobilize endothelial progenitor cells (EPCs) which can enhance arterial repair and attenuate neointimal formation, the precise explanation for the clinical PCI benefits of high dose statin therapy remain elusive. Thus we serially assessed patients undergoing PCI to test the hypothesis that high dose Atorvastatin therapy initiated prior to PCI mobilizes EPCs that may be capable of enhancing arterial repair. METHODS AND RESULTS: Statin naïve male patients undergoing angiography for stent placement were randomized to standard therapy without Atorvastatin (n = 10) or treatment with Atorvastatin 80 mg (n = 10) beginning three days prior to stent implantation. EPCs were defined by flow cytometry (e.g., surface marker profile of CD45dim/34+/133+/117+). As well, we also enumerated cultured angiogenic cells (CACs) by standard in vitro culture assay. While EPC levels did not fluctuate over time for the patients free of Atorvastatin, there was a 3.5-fold increase in EPC levels with high dose Atorvastatin beginning within 3 days of the first dose (and immediately pre-PCI) which persisted at 4 and 24 hours post-PCI (p<0.05). There was a similar rise in CAC levels as assessed by in vitro culture. CACs cultured in the presence of Atorvastatin failed to show augmented survival or VEGF secretion but displayed a 2-fold increase in adhesion to stent struts (p<0.05). CONCLUSIONS: High dose Atorvastatin therapy pre-PCI improves EPC number and CAC number and function in humans which may in part explain the benefit in clinical outcomes seen in patients undergoing coronary interventions

Opposing effects of monomeric and pentameric C-reactive protein on endothelial progenitor cells

C-reactive protein (CRP) has been linked to the pathogenesis of atherosclerosis. The dissociation of native, pentameric (p)CRP to monomeric (m)CRP on the cell membrane of activated platelets has recently been demonstrated. The dissociation of pCRP to mCRP may explain local pro-inflammatory reactions at the site of developing atherosclerotic plaques. As a biomarker, pCRP predicts cardiovascular adverse events and so do reduced levels and function of circulating endothelial progenitor cells (EPCs). We hypothesised that mCRP and pCRP exert a differential effect on EPC function and differentiation. EPCs were treated with mCRP or pCRP for 72 h, respectively. Phenotypical characterisation was done by flow cytometry and immunofluorescence microscopy, while the effect of mCRP and pCRP on gene expression was examined by whole-genome gene expression analysis. The functional capacity of EPCs was determined by colony forming unit (CFU) assay and endothelial tube formation assay. Double staining for acetylated LDL and ulex lectin significantly decreased in cells treated with pCRP. The length of tubuli in a matrigel assay with HUVECs decreased significantly in response to pCRP, but not to mCRP. The number of CFUs increased after pCRP treatment. RNA expression profiling demonstrated that mCRP and pCRP cause highly contradictory gene regulation. Interferon-responsive genes (IFI44L, IFI44, IFI27, IFI 6, MX1, OAS2) were among the highly up-regulated genes after mCRP, but not after pCRP treatment. In conclusion, EPC phenotype, genotype and function were differentially affected by mCRP and pCRP, strongly arguing for differential roles of these two CRP conformations. The up-regulation of interferon-inducible genes in response to mCRP may constitute a mechanism for the local regulation of EPC function

Time‐ and frequency‐domain analysis of repolarization phase during recovery from exercise in healthy subjects

Background/aim: Recently, data from temporal dispersion of myocardial repolarization analysis have gained a capital role in the sudden cardiac death risk stratification. Aim of this study was to evaluate the influence of heart rate, autonomic nervous system and controlled breathing on different myocardial repolarization markers in healthy subjects. Method: Myocardial repolarization dispersion markers from short period (5-minutes) ECG analysis (time and frequency domain) have been obtained in 21 healthy volunteers during these conditions: free breathing (rest); controlled breathing (resp); the first 5-minutes of post-exercise recovery phases (exercisePeak); maximum sympathetic activation, and during the second five minutes of post-exercise recovery phases (exerciseRecovery), intermediate sympathetic activation. Finally, we analyzed the whole repolarization (QTe), the QT peak (QTp) and T peak - T end intervals (Te). Results: During the exercisePeak major part of repolarization variables changed in comparison to the rest and resp conditions. Particularly, QTe, QTp, Te standard deviations (QTeSD, QTpSD, TeSD), variability indexes (QTeVI, QTpVI), normalized variances (QTeVN, QTpVN, TeVN), the ratio between short term QTe, QTp, Te variability RR (STVQTe/RR, STVQTp/RR and STVTe/RR increased. During exerciserecovery QTpSD (p&lt;0.05), QTpVI (p&lt;0.05), QTeVN (p&lt;0.05), QTpVN (p&lt;0.001), TeVN (p&lt;0.05), STVQTe/RR (p&lt;0.05), STVQTp/RR (p&lt;0.001) and STVTe/RR (p&lt;0.001) were significantly higher in comparison with the rest. The slope between QTe (0.24±0.06) or QTp (0.17±0.06) and RR were significantly higher than Te (0.07±0.06, p&lt;0.001). Conclusion: Heart rate and sympathetic activity, obtained during exercise, seem able to influence the time domain markers of myocardial repolarization dispersion in healthy subjects whereas they do not alter any spectral components