Impact of elastin incorporation into electrochemically aligned collagen fibers on mechanical properties and smooth muscle cell phenotype

Abstract

Application of tissue-engineered vascular grafts (TEVGs) for the replacement of small-diameter arteries is limited due to thrombosis and intimal hyperplasia. Previous studies have attempted to address the limitations of TEVGs by developing scaffolds that mimic the composition (collagen and elastin) of native arteries to better match the mechanical properties of the graft with the native tissue. However, most existing scaffolds do not recapitulate the aligned topography of the collagen fibers found in native vessels. In the current study, based on the principles of isoelectric focusing, two different types of elastin (soluble and insoluble) were incorporated into highly oriented electrochemically aligned collagen (ELAC) fibers and the effect of elastin incorporation on the mechanical properties of the ELAC fibers and smooth muscle cell (SMC) phenotype was investigated. The results indicate that elastin incorporation significantly decreased the modulus of ELAC fibers to converge upon that of native vessels. Further, a significant increase in yield strain and decrease in Young's modulus was observed on all fibers post SMC culture compared with before the culture. Real-time polymerase chain reaction results showed a significant increase in the expression of α-smooth muscle actin and calponin on ELAC fibers with insoluble elastin, suggesting that incorporation of insoluble elastin induces a contractile phenotype in SMCs after two weeks of culture on ELAC fibers. Immunofluorescence results showed that calponin expression increased with time on all fibers. In conclusion, insoluble elastin incorporated ELAC fibers have the potential to be used for the development of functional TEVGs for the repair and replacement of small-diameter arteries.

Proteins and Peptides as Important Modifiers of the Polymer Scaffolds for Tissue Engineering Applications—A Review

“…Cell culture experiments revealed that unlike collagen biomaterial, collagen/elastin scaffold promoted smooth muscle cell (SMC) differentiation towards contractile state as proven by enhanced expression of characteristic proteins-α-SMA, calponin, and SM-MHC. Similarly, Nguyen et al [191] proved that Young's moduli of collagen fibers enriched with insoluble or soluble elastin were approximately three-and five-fold lower compared to collagen fibers alone. However, both types of collagen/elastin fibers significantly increased expression of α-SMA, calponin, and thrombospondin in SMCs.…”

Bioglass incorporation improves mechanical properties and enhances cell‐mediated mineralization on electrochemically aligned collagen threads

“…BG was incorporated within ELAC threads by following a previously published protocol with slight modifications . Briefly, acid soluble monomeric type I bovine collagen solution (Purecol, 3.1 mg/mL, Advanced Biomatrix, CA) was dialyzed against water for 24 h. A stock solution of BG particles (46.1 mol % SiO 2 , 26.9 mol % CaO, 24.4 mol % Na 2 O, 2.5 mol % P 2 O 5 ; GLO160P/‐20; ∼20 µm particle size; MO‐SCI Corporation, MO) was prepared by suspending the particles at a concentration of 200 mg/mL in water.…”

Elastin in the Liver

“…TE inhibits SMC migration and proliferation in culture (Karnik et al, 2003a). Insoluble elastin incorporated into collagen scaffolds reduces their stiffness in a concentration dependent manner and modulates SMC phenotype toward a contractile state (Ryan and O'Brien, 2015; Nguyen et al, 2016). Eln +/+ cells have a spindle-shaped morphology with prominent stress fibers in contrast to the epitheloid-like morphology of Eln −/− cells (Karnik et al, 2003b).…”