Sterilization and Cross-Linking Combined with Ultraviolet Irradiation and Low-Energy Electron Irradiation Procedure: New Perspectives for Bovine Pericardial Implants in Cardiac Surgery

Abstract

Background Bovine pericardium is the major natural source of patches and aortic valve substitutes in cardiac repair procedures. However, long-term tissue durability and biocompatibility issues lead to degeneration (e.g., calcification) that requires reoperation. Tissue preparation strategies, including glutaraldehyde fixation, are reasons for the deterioration of pericardial tissues. We describe a pretreatment procedure involving sterilization and cross-linking combined with ultraviolet (UV) irradiation and low-energy electron irradiation (SULEEI). This innovative, glutaraldehyde-free protocol improves the mechanical aspects and biocompatibility of porcine pericardium patches. Methods We adopted the SULEEI protocol, which combines decellularization, sterilization, and cross-linking, along with UV irradiation and low-energy electron irradiation, to pretreat bovine pericardium. Biomechanics, such as ultimate tensile strength and elasticity, were investigated by comparing SULEEI-treated tissue with glutaraldehyde-fixed analogues, clinical patch materials, and an aortic valve substitute. Histomorphological and cellular aspects were investigated by histology, DNA content analysis, and degradability. Results Mechanical parameters, including ultimate tensile strength, elasticity (Young's modulus), and suture retention strength, were similar for SULEEI-treated and clinically applied bovine pericardium. The SULEEI-treated tissues showed well-preserved histoarchitecture that resembled all pericardial tissues investigated. Fiber density did not differ significantly. DNA content after the SULEEI procedure was reduced to less than 10% of the original tissue material, and more than 50% of the SULEEI-treated pericardium was digested by collagenase. Conclusion The SULEEI procedure represents a new treatment protocol for the preparation of patches and aortic valve prostheses from bovine pericardial tissue. The avoidance of glutaraldehyde fixation may lessen the tissue degeneration processes in cardiac repair patches and valve prostheses.

Decellularized extracellular matrix scaffolds: Recent trends and emerging strategies in tissue engineering

“… [ 130 , 133 , [135] , [136] , [137] , [138] , [139] , [140] ] Need lengthy incubation time. Disrupt elastin and collagen structure Dispase Cleave specific peptides (collagen Ⅳ and fibronectin) in the basement membranes Damage basement membranes and ECM [ 67 ] Lipase Catalyze the hydrolysis of lipids and aids in delipidation Hard to remove all lipids [ 141 , 142 ] Phospholipase Hydrolyze phospholipid components of cells and solubilizes cells Significantly reduce GAG content [ 143 , 144 ] …”

In vivo application of a glutaraldehyde-free, UVA/riboflavin cross-linked bovine pericardium confirms suitability for cardiovascular substitutes

“…The mechanical properties of SULEEI-treated pericardium were intensively tested in previous studies, well-defining comparable ultimate tensile strength, elasticity (Young's modulus), and suture retention strength toward clinically applied pericardial tissue. 29 Brillouin confocal microscopy has been recently validated as a valuable tool to determine the biomechanical properties of bovine pericardial tissue. 49 Here, we used this optical contactless method to measure the tissue stiffness of small pericardial implants before and after implantation (10 mm diameter discs).…”

“…28 The resulting pericardial tissue exhibits improved cytotoxicity, comparable hemocompatibility, and mechanical properties to GA-treated tissue and shows a retained α-helical structure, which is supposed to be less prone to deterioration. [28][29][30][31] The herein presented comprehensive testing of SULEEI-pericardium for biocompatibility and calcification potential after subcutaneous implantation in vivo is an essential requirement for ongoing large animal testing in aortic valve position and further clinical application.…”

Immunogenicity of decellularized extracellular matrix scaffolds: a bottleneck in tissue engineering and regenerative medicine

“…UV irradiation and treatment are common physical crosslinking methods that offer simultaneous sterilization with no need for cytotoxic chemicals [211,212]. In dehydrothermal treatment, dECM scaffolds are heated under vacuum conditions.…”