Injected matrix stimulates myogenesis and regeneration of mouse skeletal muscle after ischaemic injury

Abstract

Biomaterial-guided regeneration represents a novel approach for the treatment of myopathies. Revascularisation and the intramuscular extracellular matrix are important factors in stimulating myogenesis and regenerating muscle damaged by ischaemia. In this study, we used an injectable collagen matrix, enhanced with sialyl Lewis X (sLe X), to guide skeletal muscle differentiation and regeneration. The elastic properties of collagen and sLe X-collagen matrices were similar to those of skeletal muscle, and culture of pluripotent mESCs on the matrices promoted their differentiation into myocyte-like cells expressing Pax3, MHC3, myogenin and Myf5. The regenerative properties of matrices were evaluated in ischaemic mouse hind-limbs. Treatment with the sLe X-matrix augmented the production of myogenic-mediated factors insulin-like growth factor (IGF)-1, and IGF binding protein-2 and-5 after 3 days. This was followed by muscle regeneration, including a greater number of regenerating myofibres and increased transcription of Six1, M-cadherin, myogenin and Myf5 after 10 days. Simultaneously, the sLe X-matrix promoted increased mobilisation and engraftment of bone marrow-derived progenitor cells, the development of larger arterioles and the restoration of tissue perfusion. Both matrix treatments tended to reduce maximal forces of ischaemic solei muscles, but sLe X-matrix lessened this loss of force and also prevented muscle fatigue. Only sLe X-matrix treatment improved mobility of mice on a treadmill. Together, these results suggest a novel approach for regenerative myogenesis, whereby treatment only with a matrix, which possesses an inherent ability to guide myogenic differentiation of pluripotent stem cells, can enhance the endogenous vascular and myogenic regeneration of skeletal muscle, thus holding promise for future clinical use.

Necrotic Myocardial Cells Release Damage‐Associated Molecular Patterns That Provoke Fibroblast Activation In Vitro and Trigger Myocardial Inflammation and Fibrosis In Vivo

“…DAMPs activate macrophages, dendritic cells, and endogenous precursor stem cells that are required for initiating tissue repair 8,27,28. DAMPs have been shown to induce the proliferation of smooth muscle cells and fibroblasts29 and to stimulate angiogenesis30 and skeletal and cardiac myogenesis,27,30 as well as to promote regeneration of renal tubule cells and liver cells 31,32. These reports are consistent with the observations in the present study, wherein we demonstrate that cardiac DAMPs are sufficient to increase fibroblast proliferation and mobility, increase collagen synthesis, and activate a repertoire of gene ontologies that are involved in the response to wounding and angiogenesis (Figure 2).…”

Regulating myogenic differentiation of mesenchymal stem cells using thermosensitive hydrogels

“…Hydrogels are one type of matrix widely used to deliver cells for muscle regeneration [36]. These include collagen [37], alginate [38], fibrin [35,39], hyaluronic acid [40], and poly(ethylene glycol) [41]. Hydrogel modulus may be used to induce stem cell myogenic differentiation.…”

A necrotic stimulus is required to maximize matrix-mediated myogenesis in mice

“…MCK , a late marker of myogenesis, was not increased with matrix treatment, implying that the observed myogenesis had not yet reached a stage of late maturation. Treatment of ischemic muscle – another disease state characterized by necrotic degeneration – with the same collagen matrix also resulted in increased expression of myogenic genes, but not in Pax7 transcripts (Kuraitis et al, 2012a). It is curious that, despite the striking functional improvements and molecular myogenesis in the mdx and ischemic models, no indication of myogenesis was evident in atrophic animals.…”

“…The use of naturally derived materials that mimic healthy ECM is a promising therapeutic option and also bypasses risks associated with other treatments, such as the need for immunosuppressant drugs, induction of endogenous inflammatory responses and the difficulties associated with cell culture (Kuraitis et al, 2012b). We have recently used collagen-based matrices to augment regeneration in ischemic skeletal muscle (Kuraitis et al, 2012a). The objectives of this study were to: (i) evaluate the potential of a myogenesis-augmenting collagen matrix in different muscle disease states; (ii) characterize the interaction of this collagen matrix with SCs; and (iii) explore the role of necrotic stimuli in matrix-mediated myogenesis.…”