The application of a thermoresponsive chitosan/β‐GP gel to enhance cell repopulation of decellularized vascular scaffolds

Abstract

Decellularized arterial scaffolds have achieved success in advancing towards clinical use for small diameter vascular graft applications. Issues remain with effectively cell seeding these scaffolds, which may result in slow remodeling in vivo and reduced patency rates. This study aims to efficiently bulk load decellularized arterial scaffolds with cells and/or growth factors to promote cell migration within the scaffold. A chitosan/β-glycerophosphate (β-GP) hydrogel was used as a delivery vehicle for scaffold repopulation with rat mesenchymal stem cells (rMSCs) and/or murine hepatocyte growth factor (HGF). The thermoresponsivity of the chitosan/β-GP HGF gel was determined by rheological analysis and the release of HGF by ELISA. The chitosan/β-GP gel was fully injectable with gelation at 30°C in ∼30 min and demonstrated sustained controlled HGF release up to 28 days. Encapsulation of rMSCs allowed for consistent efficient cell delivery within the scaffold. Directional migration toward the released HGF was demonstrated within the medial layer of the scaffold up to a distance of 3 mm. The gel/cell/growth factor combination demonstrates a means of accelerating scaffold repopulation, without costly excessive in vitro maturation times.

Cell-microenvironment interactions and architectures in microvascular systems

“…have modified 5% w/v hyaluronic acid, which is known to promote angiogenesis (Hanjaya-Putra et al, 2011), by adding methacrylate groups and used it to encapsulate cells within hydrogel and create cell docking templates for cell microarrays (Khademhosseini et al, 2006). Chitosan/β-glycerophosphate hydrogels were employed to deliver MSCs within decellularized arterial scaffolds (Sheridan et al, 2014), whereas gellan gum-hyaluronic acid spongy-like hydrogels with embedded human adipose stem cells and microvascular ECs were developed to promote neovascularization and wound closure (Cerqueira et al, 2014). Using a combination of two natural hydrogels, fibrinogen+thrombin and gelatin+transglutaminase, the quattroGel was developed by Aberle et al ., and its structural and mechanical properties were optimized to promote cell adhesion even though the proliferation rates of several cell types, including ECs, were generally unaffected.…”

Methods of tissue decellularization used for preparation of biologic scaffolds and in vivo relevance

“…54 Mechanisms by which these constructive remodeling events occur 55 include the recruitment and differentiation of stem/progenitor 56 cells [7-10] and modulation of the innate immune response 57 [11-13]. The effector molecules responsible for these processes 58 represent a combination of sequestered cytokines and chemokines 59 within the matrix, and matricryptic peptides generated or exposed 60 during the process of ECM degradation [8, [14][15][16]. Thorough 61 decellularization of source tissues to generate the ECM scaffolds 62 is critical for realization of the full potential of these ECM mediated 63 events.…”

Chitosan Hydrogels for Regenerative Engineering

“…Thermogelling chitosan hydrogels have been investigated as injectable carriers for biomedical applications [42]. One of the most extensively studied thermogelling chitosan formulations is chitosan/β-glycerophosphate (β-GP) system that can undergo sol-gel transition at or near physiological temperature.…”