Reduction of sternal adhesions is still an issue in cardiac surgery. To evaluate a new fibrillar porcine collagen absorbable membrane (Cova CARD), 16 sheep underwent a sternotomy followed by scratching of surface of the heart. They were then divided into three groups: pericardium left opened (n=4), placement of Seprafilm), the reference absorbable substitute (hyaluronic acid and carboxymethylcellulose, n=6) or of Cova CARD membrane (n=6). Four months thereafter, the animals underwent repeat sternotomy and were macroscopically assessed for the degree of resorption of the material and the intensity of adhesions. Explanted hearts were blindly evaluated for the magnitude of the inflammatory response and fibrosis. The Cova CARD membrane was almost totally absorbed by four months and replaced by a loosely adherent tissue. There was no inflammatory reaction and both the extent and density of fibrosis were minimal. The composite score (median [min;max]) integrating tightness of adhesions and histological findings of inflammation and fibrosis was two-fold lower in the Cova CARD than in the Seprafilm) group (2.0 [0;3.5] vs. 5.5 [3;7], P=0.01 by Wilcoxon test). The Cova CARD membrane might represent an attractive pericardial substitute for preventing postoperative adhesions in cardiac surgery.
International audienceSynergy between micro-nanotechnology and regenerative medicine can lead to new tools for health improvement. In this study, we investigate the efficacy of electrospun scaffolds-fabricated using clinically approved collagen – as supports for cardiomyoblast culture. The scaffolds were prepared using non-toxic solvents and crosslinking agents and characterized by scanning electron microscopy and contact angle measurements. Among different types of collagen samples, we found that atelocollagen can produce better quality of electrospun fibers than acid and basic fibrous collagen. Our results also show that the cell culture performance can be improved by adjusting the crosslinking conditions. Typically, increasing the concentration of citric acid of the cross-link agents from 5% to 10% w/w and the post-crosslink baking time from 1.5 to 2.5 h led to significant increases of the cellular colonization of the scaffold, showing three-dimensional growth of cardiac cells due to the specific morphology of the fibrous scaffolds. Finally, in vivo tests of the biocompatibility of the fabricated scaffolds have been done using a mouse model of dilated cardiomyopathy. As expected, the biocompatibility of the scaffold was found excellent and no visible inflammation was observed after the implantation up to two weeks. However, 5% citric acid electrospun collagen scaffolds was less resistant in vivo, proving again the importance of the processing parameter optimization of the electrospun scaffolds
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