Pericardial tissue for cardiovascular application: an in-vitro evaluation of established and advanced production processes.

Pericardial tissue is widely used as a biomaterial, especially for cardiovascular application. Tissue processing plays a key role in developing future scaffolds derived from biological material, yet standardized evaluation is still pending. This study presents a comprehensive assessment of different treatment protocols of bovine pericardium and compares those findings to commercially available decellularized bovine (CAB) and equine (CAE) pericardial patches. Native samples were fixed with glutaraldehyde (GA) or decellularized. These decellularized samples were subsequently either treated with GA (DEC-GA) or sterilized (DEC). Treatment effects were assessed by histological evaluation of structural and biomechanical properties. Furthermore, decellularization efficacy and accuracy of the applied sterilization protocol were evaluated. Cell seeding of processed pericardial samples with human endothelial cells constituted as biocompatibility test.GA-fixed tissue revealed structural deterioration, cytotoxicity and opposed to popular believe, GA-treatment did not lead to sterility of the samples. Biomechanical assessment revealed an increase in tensile strength of GA and a decrease of DEC and DEC-GA. DEC samples were successfully sterilized and showed good decellularization results, with a significant decrease in residual DNA. Comparative assessment revealed overall good results of CAE, yet results of CAB varied largely, e.g. decellularization efficacy or tissue thickness. Biocompatibility of DEC, CAB and CAE was confirmed by successful cell adhesion. Substantial differences of native tissue properties were observed, resulting in varying treatment efficacies. This study provides a first overview describing consequential variations among biomaterials and illustrates the necessity of multidimensional assessment and tissue quality management for biological scaffold development.

Tissue-engineering acellular scaffolds-The significant influence of physical and procedural decellularization factors.

The importance of decellularized medical products has significantly increased during the last years. In this paper, we evaluated the effects of selected physical and procedural decellularization (DC) factors with the aim to systematically assess their influence on DC results. 72 porcine aortic walls (AW) were divided into three groups and exposed to a DC solution for 4 h and 8 h, either continuously or in repeated cycles. The AW were rocked (90bpm), whirled (10 l/min), sonicated (120W, 45 kHz) or exposed to a combination of these treatments, followed by 10 washing cycles. Defining successful DC as removal of nuclei while keeping an intact extracellular matrix (ECM), we equalized the efficiency to the penetration depth (PD), obtained by DAPI fluorescence and H&E staining. Additionally, we performed scanning electron microscopy (SEM), Pentachrome and Picrosirius-Red staining. Results showed that significantly higher DC depths are achieved on outer compared to inner surfaces (61 ± 7%; p < 0.001). Furthermore, the PD showed a high time dependency for all samples. Compared to continuous rocking, we achieved a significant increase in the DC efficiency through cyclic treatments ( ∼ 43%), whirling ( ∼ 19%) and sonication ( ∼ 49%). The combined treatment supported these results. In all procedures, a skeletonized but intact Collagen fibrous network was obtained as confirmed by SEM analysis. In conclusion, we systematically identified essential factors to significantly enhance DC procedures. We highly recommend considering these factors in future DC protocols. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 153-162, 2018.