Extracellular matrix scaffold for cardiac repair

Area of Science:

• Regenerative Medicine
• Biomaterials Science
• Cardiovascular Research

Background:

• Heart failure is a major health concern.
• Tissue-engineered cardiac patches offer a promising therapeutic strategy.
• Extracellular matrix scaffolds are being investigated for myocardial repair.

Purpose of the Study:

• To evaluate urinary bladder matrix (UBM) as a scaffold for repairing infarcted left ventricles.
• To compare UBM with expanded polytetrafluoroethlyene (ePTFE) for cardiac patching.
• To assess the tissue response and regenerative potential of UBM in a porcine model.

Main Methods:

• Pigs (n=42) underwent left ventricular (LV) infarction.
• 4-layer multilaminate UBM or ePTFE patches were implanted as full-thickness LV wall replacements.
• Tissue analysis included histology, immunocytochemistry, and flow cytometry at 1 week, 1 month, and 3 months post-implantation.

Main Results:

• At 3 months, UBM was bioresorbed, replaced by vascularized, fibrocellular tissue with myofibroblasts and some contractile cells.
• UBM showed significantly more alpha-smooth muscle actin-positive cells compared to ePTFE at 1 month (P=0.04).
• ePTFE patches exhibited foreign-body response, necrosis, and calcification at 3 months, with limited cardiomyocyte markers.

Conclusions:

• Biodegradation of UBM was accompanied by the formation of fibrocellular tissue containing contractile cells.
• UBM demonstrates superiority over synthetic ePTFE for cardiac patching.
• UBM shows a trend towards myocardial replacement at 3 months post-implantation.