In vitro and in vivo Evaluation of Laminin Enriched Fibrin Hydrogels for Use following Volumetric Muscle Loss Injuries

摘要

Volumetric muscle loss (VML) is characterized by a critical loss of muscle tissue that is accompanied by severe functional impairment and often long-term disability. Clinical therapies currently employed in the treatment of VML are ineffective at regenerating lost muscle and restoring function. This study created a novel hydrogel composed of fibrinogen and laminin-111, an important basement membrane protein, in an attempt to promote regeneration and recovery of VML traumatized muscle. The hydrogels exhibited fibrous structure and Young's modulus of ~2kPa. The hydrogels also supported C2C12 myoblast proliferation, myogenic marker expression, and pro-regenerative growth factor secretion in vitro. Together, these observations suggested that the hydrogels were suitable for implantation in a VML model. Further evaluation of these hydrogels in a murine model of VML showed significant improvements in muscle weights and heightened cellular infiltration at 2 weeks post-injury compared to the untreated controls. At 4 weeks post-injury, the hydrogel treated injured muscle showed increased acetylcholine receptor clustering and induction of the anti-inflammatory M2 macrophage phenotype. However, improvements in muscle weights and force production were not observed at 4 weeks. Future studies would include measurement of force at 6-8 weeks post-injury and efforts will be made to further increase the amount of laminin-111 delivered to the defect site. Overall, these results will inform and drive the development of a successful tissue engineering strategy for the regeneration of skeletal muscle following trauma.