Cause or Effect of Arteriogenesis: Compositional Alterations of Microparticles from CAD Patients Undergoing External Counterpulsation Therapy

Abstract

Recently, a clinical study on patients with stable coronary artery disease (CAD) showed that external counterpulsation therapy (ECP) at high (300 mmHg) but not at low inflation pressure (80 mmHg) promoted coronary collateral growth, most likely due to shear stress-induced arteriogenesis. The exact molecular mechanisms behind shear stress-induced arteriogenesis are still obscure. We therefore characterized plasma levels of circulating microparticles (MPs) from these CAD patients because of their ambivalent nature as a known cardiovascular risk factor and as a promoter of neovascularization in the case of platelet-derived MPs. MPs positive for Annexin V and CD31CD41 were increased, albeit statistically significant (P<0.05, vs. baseline) only in patients receiving high inflation pressure ECP as determined by flow cytometry. MPs positive for CD62E, CD146, and CD14 were unaffected. In high, but not in low, inflation pressure treatment, change of CD31CD41 was inversely correlated to the change in collateral flow index (CFI), a measure for collateral growth. MPs from the high inflation pressure group had a more sustained pro-angiogenic effect than the ones from the low inflation pressure group, with the exception of one patient showing also an increased CFI after treatment. A total of 1005 proteins were identified by a label-free proteomics approach from MPs of three patients of each group applying stringent acceptance criteria. Based on semi-quantitative protein abundance measurements, MPs after ECP therapy contained more cellular proteins and increased CD31, corroborating the increase in MPs. Furthermore, we show that MP-associated factors of the innate immune system were decreased, many membrane-associated signaling proteins, and the known arteriogenesis stimulating protein transforming growth factor beta-1 were increased after ECP therapy. In conclusion, our data show that ECP therapy increases platelet-derived MPs in patients with CAD and that the change in protein cargo of MPs is likely in favor of a pro angiogenic/arteriogenic property.Trial RegistrationClinicalTrials.gov NCT00414297

Application of Extracellular Vesicles Proteomics to Cardiovascular Disease: Guidelines, Data Analysis, and Future Perspectives

“…They also highlighted the upregulation of thrombospondin‐1 (TSP1) and transforming growth factor beta‐1 (TGFB1) after ECP therapy due to their known effects on cellular homeostasis, angiogenesis, and arteriogenesis. These results provide evidence that ECP therapy increases MVs in patients with CAD and that there is a concomitant change in protein composition of MVs likely in favor of a proangiogenic/arteriogenic property …”

Dynamic microvesicle release and clearance within the cardiovascular system: triggers and mechanisms

“…External counter-pulsation is a therapy that reduces ischaemia by increasing preload and cardiac output, but also leads to significant increases in vessel shear stress. When given for sustained periods amounting to 30 h over 4 weeks, an increase in platelet-derived MVs was observed, but no change in those derived from monocytes or endothelial cells [52]. Again this could relate in part to disease modification.…”

“…This is suggested by studies which have looked at release following prolonged therapies that study MV levels after several weeks or even months from the initial baseline assessment [52,53] and show significant sustained changes in circulating MV levels. However, such studies are limited by the potential modifying effect of therapies on the underlying triggers for MV release.…”

Genome-wide identification of pathogenicity factors of the free-living amoeba Naegleria fowleri

“…The 2D gel spots were digested directly, while the gel slices were reduced and alkylated prior to digestion with trypsin and analyzed by nano-LC MS/MS as described in [70]. The generated fragment spectra were searched against our personal ORF database obtained from RNA sequencing (see above) using EasyProt software [71].…”