Secretome of apoptotic peripheral blood cells (APOSEC) attenuates microvascular obstruction in a porcine closed chest reperfused acute myocardial infarction model: role of platelet aggregation and vasodilation

Abstract

Although epicardial blood flow can be restored by an early intervention in most cases, a lack of adequate reperfusion at the microvascular level is often a limiting prognostic factor of acute myocardial infarction (AMI). Our group has recently found that paracrine factors secreted from apoptotic peripheral blood mononuclear cells (APOSEC) attenuate the extent of myocardial injury. The aim of this study was to determine the influence of APOSEC on microvascular obstruction (MVO) in a porcine AMI model. A single dose of APOSEC was intravenously injected in a closed chest reperfused infarction model. MVO was determined by magnetic resonance imaging and cardiac catheterization. Role of platelet function and vasodilation were monitored by means of ELISA, flow cytometry, aggregometry, western blot and myographic experiments in vitro and in vivo. Treatment of AMI with APOSEC resulted in a significant reduction of MVO. Platelet activation markers were reduced in plasma samples obtained during AMI, suggesting an anti-aggregatory capacity of APOSEC. This finding was confirmed by in vitro tests showing that activation and aggregation of both porcine and human platelets were significantly impaired by co-incubation with APOSEC, paralleled by vasodilator-stimulated phosphoprotein (VASP)-mediated inhibition of platelets. In addition, APOSEC evidenced a significant vasodilatory capacity on coronary arteries via p-eNOS and iNOS activation. Our data give first evidence that APOSEC reduces the extent of MVO during AMI, and suggest that modulation of platelet activation and vasodilation in the initial phase after myocardial infarction contributes to the improved long-term outcome in APOSEC treated animals.Electronic supplementary materialThe online version of this article (doi:10.1007/s00395-012-0292-2) contains supplementary material, which is available to authorized users.

Peripheral Blood Mononuclear Cell Secretome for Tissue Repair

“…Both methods revealed improved microvascular blood flow in treated animals. In addition, apoptotic PBMC-S induced up-regulation of eNOS, iNOS in cultured H UVECs, and vasodilator-stimulated phosphoprotein (VASP) activation in platelets [99]. These data indicate that apoptotic PBMC-S not only caused direct cytoprotective effects in injured hearts, but also induced systemic effects on circulating platelets and endothelial cells.…”

Therapeutic Potential of Paracrine Factors and Secretome-based Treatment in Spinal Cord Injury

“…ApoSec was able to induce angiogenesis not only in aortic rings, but also in spinal cord tissue ex-vivo, which was confirmed immunohistologically using confocal microscopy [31] . Aside from neovascularization, previously described inhibition of micro-vascular obstruction via inhibition of thrombocyte activation and vasodilation might also be involved in observed improved vascularity in treated animals [24,31] . To assess possible involved immunologic mechanisms further investigation revealed higher levels of CD68 expression with concomitant lower expression levels of inducible NO-synthase (iNOS) 3 days after injury in animals treated with ApoSec.…”

“…Subsequent centrifugation allowed further processing of the cell-free supernatant or secretome, also referred to as conditioned medium. Several pre-clinical models were used to investigate the therapeutic potential of this secretome derived from apoptotic PBMCs (ApoSec, patent number: WO2010/070105, WO2010/079086) [22][23][24][25][26][27][28] . Therapeutic efficacy was shown to be a synergistic effect caused by modulation of multiple molecular pathways, many of which are also known to be involved in secondary cascades after SCI.…”

“…Firstly, ApoSec was shown to up-regulate pathways associated with cell survival and inhibition of apoptosis in-vitro and in-vivo [26][27][28][29] . Secondly, the secretome of apoptotic PBMCs improves microvascular flow via inhibition of thrombocyte activation and vasodilation and features angiogenic characteristics [24,28] . Thirdly, ApoSec was shown to be capable of modulating the inflammatory response in-vitro and in-vivo [25] .…”

Peripheral blood mononuclear cell secretome for tissue repair

“…Hoetzenecker et al showed that, in addition to an effect on intracellular myocardial signaling cascades, apoptotic PBMC-S preserved porcine epi/myocardial microvascular perfusion in a closed chest reperfusion infarction model [99]. Microvascular obstruction was measured by functional magnetic resonance imaging (fMRI) and cardiac catheterization in treated animals.…”