Sequential hydrophile and lipophile solubilization as an efficient method for decellularization of porcine aortic valve leaflets: Structure, mechanical property and biocompatibility study.

Antigenicity of xenogeneic tissues is the major obstacle to increased use of these materials in clinical medicine. Residual xenoantigens in decellularized tissue elicit the immune response after implantation, causing graft failure. With this in mind, the potential use is proposed of three protein solubilization-based protocols for porcine aortic valve leaflets decellularization. It was demonstrated that hydrophile solubilization alone achieved incomplete decellularization; lipophile solubilization alone (LSA) completely removed all cells and two most critical xenoantigens - galactose-α(1,3)-galactose (α-Gal) and major histocompatibility complex I (MHC I) - but caused severe alterations of the structure and mechanical properties; sequential hydrophile and lipophile solubilization (SHLS) resulted in a complete removal of cells, α-Gal and MHC I, and good preservation of the structure and mechanical properties. In contrast, a previously reported method using Triton X-100, sodium deoxycholate and IGEPAL CA-630 resulted in a complete removal of all cells and MHC I, but with remaining α-Gal epitope. LSA- and SHLS-treated leaflets showed significantly reduced leucocyte activation (polymorphonuclear elastase) upon interaction with human blood in vitro. When implanted subdermally in rats for 6 weeks, LSA- or SHLS-treated leaflets were presented with more biocompatible implants and all four decellularized leaflets were highly resistant to calcification. These findings illustrate that the SHLS protocol could be considered as a promising decellularization method for the decellularization of xenogeneic tissues in tissue engineering and regenerative medicine. Copyright © 2016 John Wiley & Sons, Ltd.

Should a Mechanical or Biological Prosthesis Be Used for a Tricuspid Valve Replacement? A Meta-Analysis.

BACKGROUND AND AIM OF THE STUDY: The prosthesis of choice for a tricuspid valve replacement is still unkown. This meta-analysis was undertaken to review the results of mechanical and bioprosthetic valves in the tricuspid position. METHODS: We identified all relevant studies published in the past 20 years (from January 1, 1995 to December 31, 2014) through the Embase, Current Contents, and PubMed databases. The hazard ratio and its 95% confidence limits were utilized to evaluate time-to-event related effects of surgical procedures. The Q-statistic, Index of Inconsistency test, funnel plots, and Egger's test were used to assess the degree of heterogeneity and publication bias. Random effects models were used, and study quality was also assessed. RESULTS: In our meta-analysis, 22 studies published from 1995 to 2014 were reviewed and 2630 patients and 14,694 follow-up years were analyzed. No statistically significant difference was identified between mechanical and biological valves in terms of survival, reoperation, and prosthetic valve failure. The respective pooled hazard ratio estimates were 0.95 (0.79 to 1.16, p = 0.62, I(2) = 29%), 1.20 (0.84 to 1.71, p = 0.33, I(2) = 0%), and 0.35 (0.06 to 2.01, p = 0.24, I(2) = 0%). A higher risk of thrombosis was found in mechanical tricuspid valve prostheses (3.86, 1.38 to 10.82, p = 0.01, I(2) = 0%). CONCLUSIONS: No statistically significant difference was identified between mechanical and biological valves in terms of survival, reoperation, or prosthetic valve failure, but mechanical tricuspid valve prostheses had a higher risk of thrombosis. doi: 10.1111/jocs.12730 (J Card Surg 2016;31:294-302).