Tissue Engineering of Heart Valves

Abstract

Background-Tissue-engineered or decellularized heart valves have already been implanted in humans or are currently approaching the clinical setting. The aim of this study was to examine the migratory response of human monocytic cells toward decellularized porcine and human heart valves, a pivotal step in the early immunologic reaction. Methods and Results-Porcine and human pulmonary valve conduits were decellularized, and migration of U-937 monocytic cells toward extracted heart valve proteins was examined in a transmigration chamber in vitro. Homogenized tissue specimens were size fractionated by SDS-PAGE. ). SDS-PAGE of the pulmonary heart valve tissue revealed that considerable amounts of proteins with different molecular weights that were not detected in the human equivalent remain in the decellularized porcine heart valve. Conclusions-We describe for the first time that the remaining potential of decellularized pulmonary heart valves to attract monocytic cells depends strongly on whether porcine or human scaffolds were used. These findings will have an important impact on further investigations in the field of heart valve tissue engineering.

The influence of heart valve leaflet matrix characteristics on the interaction between human mesenchymal stem cells and decellularized scaffolds

“…and type I collagen patches in the peritoneum cavity suggest that treatment with detergents makes the valve matrix more immunogenic, probably due to fine molecular alterations of the ECM system (publication in preparation). Using in vitro assays, Rieder et al ascertained that decellularized porcine pulmonary valve conduits are able to attract more monocytic cells than their human counterparts [39]. The same group also demonstrated that human polymorphonuclear leukocyte activation, subsequent to the contact of decellularized porcine matrices with human plasma, can be blocked by inhibitory elements extracted in the decellularization process [40], thus suggesting that an appropriate matching of the host (scaffold) to the donor (patient' s cells) is of paramount importance for the successful outcome of tissue engineering experiments.…”

Preclinical Testing of Tissue-Engineered Heart Valves Re-Endothelialized Under Simulated Physiological Conditions

“…4 Because of higher immune histocompatibility, comparable anatomic geometry, and structure, allogeneic scaffolds might be used successfully for TE despite the limited availability of human material. 5,9 The need for repopulation of valve scaffolds either in vitro or in vivo and the choice of cells is, however, still controversially discussed. 3-5,8 -11 Efficient tissue regeneration has been obtained by repopulation of biological decellularized scaffolds with interstitial cells in vivo.…”

Decellularized aortic conduits: could their cryopreservation affect post-implantation outcomes? A morpho-functional study on porcine homografts

“…However, PTGs were significantly higher than the preoperative gradients and the short-term nature of this event precludes the genesis of a pathological stenosis. It is likely that PTG modification may depend on mechanical factors, such as anatomy of aortic root, patient-prosthesis mismatch, or pressure recovery, and biological factors, such as infection, coagulation, inflammation, cell repopulation, and ECM synthesis [28,29]. Of interest, an in vitro study demonstrated that TRICOL-treated valves showed lower gradients than in controls (non-decellularized, native valves) [17].…”