Histological and Mechanical Assessment of Decellularized Porcine Biografts, and Its Biological Evaluation following Aortic Implantation during Mid-Term Follow-Up

Abstract

Aims: Prosthetic graft infection frequently requires graft replacement. Among other options, a biological graft could serve as an alternative choice. Decellularization reduces tissue immunogenicity. Our aim was to determine an efficient decellularization method and to evaluate the decellularized porcine biografts’ adaptability. Methods: Four different protocols were implemented to decellularize porcine aortic segments (n = 4). Cell removal effectiveness and matrix structure preservation were histologically examined. Mechanical tests were performed. Decellularized porcine grafts were interpositioned in a porcine aorta. After a 6-month period, implanted samples were removed and evaluated using light and electron microscopy. Results: Histological results showed complete removal of cells and preserved connective tissue fiber structure following decellularization, using sodium dodecyl sulfate and sodium azide. Pressure tests demonstrated similar compliance to fresh vessels. In 9 out of 10 cases, pigs survived the follow-up period. Graft rejection, intimal hyperplasia, reocclusion and/or aneurysm formation were not observed. Presence of host cells and neoendothelialization were microscopically confirmed. Conclusions: This decellularization protocol enables a cost-effective preparation of biological grafts featuring reduced immunogenicity. The implanted grafts did not degenerate during the 6-month follow-up period, the lack of graft rejection suggests acceptable immunological tolerance, while recipient cells migrate into, proliferate and differentiate, thus creating the possibility for further use as an optional vascular graft.

DSC and histological analysis of decellularized porcine biograft

“…However, frequent, late aneurysm formation due to their degeneration is the most unfavorable consequence of their use. A well-known reason behind it is the immunemediated graft rejection [6,10,15]. Several different types of mechanical tests were previously performed; nevertheless, none of them could provide information on, whether there was any association between late graft degeneration and decellularization treatment.…”

“…Earlier attempts demonstrated adequate biomechanical properties and suture retention of cell-free vascular grafts [3,10]. However, these investigations did not provide eligible information about the microstructural changes in the connective tissue fibers that may influence the mechanical stability and long-term behavior of these decellularized vessels.…”

“…Aortic segments were decellularized through continuous shaking in 1% sodium dodecyl sulfate (SDS; Sigma-Aldrich Chemie GmbH, Steinheim, Germany), 0.05% sodium azide (NaN 3 ; Alfa Aesar GmbH & Co, Karlsruhe, Germany) and phosphate-buffered saline (PBS; Sigma-Aldrich Chemie GmbH, Steinheim, Germany), at room temperature, for 48 h. The solution was exchanged in every 6 h. At the end of the decellularization protocol, the aortic segments were washed using PBS for 12 h to effectively remove residual detergents and cell debris, then stored in Medium 199 with Earle's salts (Biowest, Nuaillé, France) and maintained at 4 °C, until measurements [9,10].…”

“…After doubtful early attempts [1,2], the attention has pointed toward the development of biological xenografts with adequate biomechanical properties, high resistance against infections and unlimited availability [3][4][5]. By decellularization of the vessel, the immunogenicity can be reduced, preventing the implanted graft from deterioration [3][4][5][6][7][8][9][10]. Several efficient decellularization methods were previously published testing the mechanical properties of treated vessels with different methodologies [3,4,[6][7][8][9][10]; however, mechanical stability of cell-free grafts based on differential scanning calorimetry (DSC) in consideration of histological evaluation was first assessed in our study.…”

Aortic Reconstruction with Cryopreserved Human Allograft in a Hemodialysis Patient with Abdominal Aortic Aneurysm after Surgical Treatment of Liver Abscess

“…Although the immune response is also a disputable issue, and the advisability of long-term use of immunosuppressive agents is still under discussion. 8 In the postoperative period, we prescribed prednisone at a dose of 5 mg once a day for a month.…”