Humanized rodent models have been used extensively for studying autoimmune diseases, viral infections, xenogeneic transplantation and, more recently, allogenic stem cell transplantation; however, until now, researchers have not used these murine models for studies in the field of biomaterials. In their recent paper published in Biomaterials, Wang et al used a humanized mouse model to “assess the human immune response to decellularized extracellular matrix (ECM) biomaterials, specifically injectable hydrogels derived from porcine or human myocardium, which Biomaterials, Wang et al used a humanized mouse model to “assess the human immune response to decellularized extracellular matrix (ECM) biomaterials, specifically injectable hydrogels derived from porcine or human myocardium, which were initially developed to treat the heart post-myocardial infarction.”

This is important because the rodents typically used for biocompatibility testing provide limited representation of the human immune response because of differences in immune cell receptors, cytokine expression and response to various stimuli highlight how responses in rodents might not correlate with outcomes observed in humans. “Immune cells in the humanized mouse model, particularly T-helper cells, responded distinctly between the xenogeneic and allogeneic biomaterials,” according to Wang et al. “The allogeneic extracellular matrix derived hydrogels elicited significantly reduced total, human specific, and CD4 T-helper cell infiltration in humanized mice compared to xenogeneic extracellular matrix hydrogels, which was not recapitulated in wild type mice.”

Although this model certainly still has some limitations, the study was successful and gives high hopes to improving outcomes in the field of biomaterials, which continue to play an integral role in applications related to wound healing, hernia repair, skeletal muscle defect repair and hear attacks. As suggested by Wang et al, “decellularized ECM biomaterials are an attractive platform for biomaterial therapies since tissue derived from ECM can promote tissue remodeling by influencing cellular metabolism, proliferation, migration, maturation and differentiation” and these humanized mouse models will allow for further study of human immune cell responses to biomaterials in an in vivo environment.