Additive Benefits of Chondroitin Sulfate and Oriented Tethered Epidermal Growth Factor for Vascular Smooth Muscle Cell Survival

Abstract

An anti-apoptotic coating combining chondroitin sulfate (CS) and coiled-coil-based tethering of epidermal growth factor (EGF) is designed for vascular applications. The oriented tethering strategy enables to reach higher EGF surface densities compared to the commonly used random covalent grafting, while using much lower concentrations of EGF during incubation. It also significantly improves vascular smooth muscle cell (VSMC) survival and resistance to apoptosis in serum-free conditions. The comparison of CS and low-fouling carboxymethylated dextran as a sublayer for growth factors highlights the tremendous benefit of CS thanks to its selective protein resistance and good cell adhesion properties. This approach can be tuned by capturing other growth factors on CS through coiled-coil interactions.

Controlled co-immobilization of EGF and VEGF to optimize vascular cell survival

“…As opposed to HUVEC, E-VEGF immobilization alone showed little enhancement of AoSMC survival (31 ± 5 % for surfaces incubated with E-VEGF at 20 nM compared to 20 ± 7 % for bare CS surfaces). However, as previously reported, the coiled-coil immobilization of E-EGF on CS led to a significant increase in cell survival, [37] and this pro-survival effect increased with the E-EGF incubation concentration (from 27 ± 12 % for 0.1-nM E-EGF to 53 ± 9 % for 20-nM E-EGF). Once again, a further increase in cell survival was observed for surfaces incubated with a mixture of GFs.…”

“…Indeed, in a previous study, we observed that the coiled-coil mediated EGF immobilization allowed higher capture efficiencies compared to covalent grafting. [37] Another explanation for the signal saturation we observed, especially in the case of E-VEGF, could be a saturation of the Kcoil units on CS, since the secondary capture of E-EGF on surfaces pre-incubated with E-VEGF at concentrations higher than 5 nM did not occur (Fig. 3).…”

“…[34] Ecoil/Kcoil mediated capture has been successfully applied to tether various Ecoil-tagged GFs, such as the epidermal growth factor (EGF) [35] and the vascular endothelial growth factor (VEGF), [36] onto substrates that had been predecorated with Kcoil peptides. Careful positioning of the Ecoil tags on the chimeras corresponding to each GF allowed this immobilization strategy to preserve the GF bioactivity after tethering (as deduced from receptor activation, [34] increase in adhesion [27], proliferation [27] or survival [36,37] of cells). Of interest, coiled-coil immobilized and free EGF and VEGF led to comparable cell survival when provided at sufficiently high doses.…”

“…Of interest, coiled-coil immobilized and free EGF and VEGF led to comparable cell survival when provided at sufficiently high doses. [36,37] Although this system had been limited so far to the immobilization of a single type of GF at a time, we hypothesized that Kcoil-bearing substrates could readily be functionalized with multiple Ecoil-tagged GFs. The objective of this work was therefore to investigate the feasibility of GF co-immobilization, its control and the advantage of the stable coiled-coil capture system as a platform to investigate the collaborative effect between GFs and its potential to create a coating with tailored properties.…”

In Vitro and Pilot In Vivo Evaluation of a Bioactive Coating for Stent Grafts Based on Chondroitin Sulfate and Epidermal Growth Factor

“…This choice is based on previous studies that have shown the superiority of the combination of CS and EGF [14]. The coating was created on polyethylene terephtalate (PET) and expanded polytetrafluoroethylene (ePTFE) substrates (since these are the two plastic materials used in SG graft fabric) and tested in vitro for its bioactivity on vascular cells and its stability.…”