PERICARDIAL TISSUE REGENERATION BY URINARY BLADDER MATRIX SCAFFOLDS IN A PRECLINICAL PORCINE MODEL

MAURICIO RAMIREZ; AMIGO NATALIA; ROMINA LOVERA; ANDREA DE LORENZI; DAMIAN CRAIEM; ARIEL PASCANER; ALEJANDRO NIEPONICE; ADAM YOUNG; JUAN MARTIN RIGANTI; PEDRO RENDA; CARLOS VIGLIANO; THOMAS GILBERT

Mar del Plata

Congreso; XIV Encuentro Biólog@s En Red; 2019

Asociación de Jóvenes Investigadores en Formación (AJIF)

Closing the pericardium after cardiac surgery is recommended to prevent postoperative adhesions to the sternum. Synthetic materials have been used as substitutes, with limited results due to impaired remodeling and fibrotic tissue formation. Urinary bladder matrix (UBM) scaffolds promote constructive remodeling that resemble more the native tissue. Aim: Evaluate the host response to UBM scaffolds in a pre-clinical porcine model of open heart surgery. 12 Landrace pigs were subjected to median sternotomy and a 5x7cm pericardial defect was created. The test group (UBM, n=6) was repaired with a UBM device of 5x7cm. Control group (n=6) was left with the pericardium open defect. Animals were survived for 8 weeks. Endpoints included gross morphology with adhesion assessment, biomechanical testing, histology with semi-quantitative score and cardiac function (Echocardiography).Softer adhesions were found in UBM group, but strong adhesions and injury of the coronary bed were found in control group. Load at failure (gr) and stiffness (gr/mm) were lower in the UBM samples than in native pericardium (199.9±59.2g vs. 405.3±99.89g, P=0.0536 and 44.23±15.01g/mm vs. 146.5±24.38g/mm P=0.0025 respectively). In UBM group, histology resembled that of native pericardium, with neovascularization, neofibroblasts and few signs of inflammation. Control group showed fibrotic tissue with mononuclear infiltrate and no organized collagen fibers, which was validated with a histologic score. Both groups had normal results without cardiac motility disorders.In this experimental setting, UBM scaffolds contribute to enhance pericardial repair with tissue characteristics that protect against the formation of postoperative retrosternal adhesions without affecting cardiac function. Further study is necessary.