Distinct impacts of aging on the immune responses to extracellular matrix-based versus synthetic biomaterials.

All implanted materials inevitably trigger an acute inflammatory response. The long-term outcome, however, is dependent on the trajectory of this response. This study investigates the effects of aging on the immune response to two commercially available biomaterials.

Porcine Acellular Nerve-Derived Hydrogel Improves Outcomes of Direct Muscle Neurotization in Rats.

The ability to reinnervate a muscle in the absence of a viable nerve stump is a challenging clinical scenario. Direct muscle neurotization (DMN) is an approach to overcome this obstacle; however, success depends on the formation of new muscle endplates, a process, which is often limited due to lack of appropriate axonal pathfinding cues. This study explored the use of a porcine nerve extracellular matrix hydrogel as a neuroinductive interface between nerve and muscle in a rat DMN model.

Safety and efficacy of an injectable nerve-specific hydrogel in a rodent crush injury model.

Introduction/aims: While the peripheral nervous system has the inherent ability to recover following injury, results are often unsatisfactory, resulting in permanent functional deficits and disability. Therefore, methods that enhance regeneration are of significant interest. The present study investigates an injectable nerve-tissue-specific hydrogel as a biomaterial for nerve regeneration in a rat nerve crush model.

Distinct macrophage populations and phenotypes associated with IL-4 mediated immunomodulation at the host implant interface.

The host macrophage response to implants has shown to be affected by tissue location and physio-pathological conditions of the patient. Success in immunomodulatory strategies is thus predicated on the proper understanding of the macrophage populations participating on each one of these contexts. The present study uses an in vivo implantation model to analyze how immunomodulation via an IL-4 eluting implant affects distinct macrophage populations at the tissue-implant interface and how this may affect downstream regenerative processes.

Distinct release strategies are required to modulate macrophage phenotype in young versus aged animals.

The role of innate immunity and macrophages in the host response to biomaterials has received renewed attention. A context-dependent spectrum of macrophage phenotypes are shown to affect tissue integration and performance of implanted biomaterials and medical devices. Recent studies by our group demonstrated that the host response in aged animals was characterized by delayed macrophage recruitment, differences in marker expression and a shifted pro-inflammatory (M1) response, associated with an unresolved host response in the long-term.

Evaluation of the host immune response to decellularized lung scaffolds derived from α-Gal knockout pigs in a non-human primate model.

Whole organ tissue engineering is a promising approach to address organ shortages in many applications, including lung transplantation for patients with chronic pulmonary disease. Engineered lungs may be derived from animal sources after removing cellular content, exposing the extracellular matrix to serve as a scaffold for recellularization with human cells. However, the use of xenogeneic tissue sources in human transplantation raises concerns due to the presence of the antigenic Gal epitope.