Quantifying the immune response to a tissue-engineered porcine extracellular matrix

Aim: Structural valvular deterioration of xenogenic heart valve replacements is thought to be due to a chronic immune response. We sought to engineer porcine extracellular matrix that elicits minimal inflammatory immune response. Materials & methods: Whole blood, bone marrow and pericardium were collected from patients undergoing elective cardiac surgery. Porcine extracellular matrix was decellularized, reseeded with homologous mesenchymal stem cells and exposed to whole blood. Results: DAPI stain confirmed the absence of cells after decellularization, and presence of mesenchymal stem cells after recellularization. There was a significant reduction in IL-1β and TNF-α production in the recellularized matrix. Conclusion: Recellularization of porcine matrix is successful at attenuating the xenogenic immune response and may provide a suitable scaffold to address the current limitations of prosthetic heart valve replacements.Deterioration of tissue heart valve replacements is thought to be due to a chronic immune response. We sought to remove cells from a pig derived tissue and replace those cells with human stem cells to create a scaffold that results in a reduced immune response. Whole blood, bone marrow and pericardium were collected from patients undergoing elective cardiac surgery. The pig derived tissue had the cells removed, were replaced with human stem cells and exposed to whole blood. Tissue stain confirmed the absence of cells after removal, and presence of stem cells after replacement of cells. There was a significant reduction in markers of immune response in the recellularized tissue. Removal of cells from pig derived tissue and replacement with human stem cells is successful at reducing the immune response to animal tissue and may provide a suitable scaffold to address the current limitations of heart valve replacement options.