Fishman, JM;
(2013)
Characterisation and immunomodulatory effect of a decellularised skeletal muscle scaffold for tissue engineering.
Doctoral thesis , UCL (University College London).
Abstract
Objectives Decellularised (acellular) scaffolds, composed of natural extracellular matrix (ECM), form the basis of an emerging generation of tissue-engineered organ and tissue replacements with the capacity to transform healthcare. Prime requirements for allogeneic, or xenogeneic, decellularised scaffolds are biocompatibility and lack of an adverse immune response. Although the humoral-mediated immune response towards decellularised scaffolds has been well documented, there is a lack of data concerning orchestration of the cell-mediated immune response towards decellularised scaffolds both in vitro and in vivo. Methods Skeletal muscle scaffolds were decellularised, characterised in vitro and xenotransplanted. The cellular immune response to the scaffolds was evaluated by immunohistochemistry and quantified stereologically. T-cell proliferation and cytokines, as assessed by flow cytometry (FACS) using carboxy-fluorescein diacetate succinimidyl ester (CFSE) dye and cytometric bead array, formed an in vitro surrogate marker and correlate of the in vivo host immune response towards the scaffold. Results were substantiated by orthotopic transplantation of decellularised xenogeneic and allogeneic scaffolds, seeded with labelled xenogeneic and allogeneic myoblasts. Results Decellularised scaffolds were free of major histocompatibility complex (MHC) class I and II antigens and were found to exert anti-inflammatory and immunosuppressive effects, as evidenced by a prolonged biodegradation time in vivo, reduced sensitised T-cell proliferative activity in vitro, reduced IL-2, IFNγ concentrations and raised IL-10 levels in cell-culture supernatants and polarisation of the macrophage response in vivo towards an M2-phenotype. Delivery of labelled donor-derived xenogeneic and allogeneic myoblasts with decellularised scaffolds resulted in improved survival at 2 and 4 weeks in vivo. Conclusions Decellularised scaffolds polarise host responses away from a classical Th1-proinflammatory profile both in vitro and in vivo and appear to down-regulate T-cell xeno-responses and Th1 effector function by inducing a state of peripheral T-cell hypo-responsiveness. These results have substantial implications for the future clinical application of tissue-engineered therapies.
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