VASCULAR HEALING & BIORESORBABLE SCAFFOLDS: FROM PLATELETS, LEUKOCYTES TO ENDOTHELIAL CELLS


Jean-Francois Tanguay, M.D., Université de Montréal, Canada

Vascular endothelium damage occurs in acute situations such as following percutaneous coronary intervention or spontaneously plaque rupture. Tissue damages can also result from chronic conditions linked to cardiovascular risk factors such as diabetes, dyslipidemia and hypertension, which induce a sustained pro-inflammatory status and impair vascular endothelial cell functions. These alterations impact the antithrombotic properties, vascular tone control and permeability of the endothelium that releases pro-inflammatory mediators which coordinate tissue and cellular responses part of the vascular healing process. Platelet-neutrophil interactions and endothelial cells can modulate vascular healing. We have shown that vascular stents may lead to long term thrombo-inflammation and endothelial dysfunction. Furthermore, by inhibiting p-selectin and platelet-neutrophil interactions and by enhancing reendothelialisation, we demonstrated an improvement in vascular healing with a reduction in peri-procedural complications. The activation profile of endothelial cells can profoundly impact on the recruitment, firm adhesion and integration of leukocytes and bone marrow-derived progenitor cells including circulating endothelial progenitor cells. In previous studies we also showed that the 17beta-estradiol has beneficial effects on vascular cells by reducing pro-inflammatory molecule expression by endothelial cells and by modulating smooth muscle cells proliferation and migration. Drug-eluting stents reduce restenosis, however, long term vascular effects and late thrombo-inflammatory reactions could mitigate the initial clinical benefits. Resorbable vascular scaffolds offer a promising new approach to revascularisation combining drug elution to reduce restenosis and resorption with restoration of endothelial function. Conclusion: Platelet-neutrophil interactions and endothelial dysfunction can impact on vascular healing. While drug-eluting stents reduce restenosis, bioresorbable vascular scaffolds may offer a promising platform for revascularisation.