Search

Autologous vascular arterial or venous graft are not available in 10-40% of patients, due to vascular pathologies, and the utility of decellularized biological scaffolds would be a solution for those cases. The purpose of this research was to obtain a functional acellular xenograft, prior to in-vivo testing as a vascular graft in an experimental animal.

Background: We hypothesized that an ideal heart valve replacement would be acellular valve root scaffolds seeded with autologous stem cells. To test this hypothesis, we prepared porcine acellular pulmonary valves, seeded them with autologous adipose derived stem cells (ADSCs) and implanted them in sheep and compared them to acellular valves.

Introduction: Present valvular substitutes are imperfect prostheses. Regenerative medicine imagines a viable prototype using stem cells, scaffolds and bioreactors. In our study we aimed to differentiate sheep adipose derived stem cells (ADSCs) towards endothelial cells using chemical and mechanical stimuli. For mechanical stimulation, a cooling system was imagined, adapting to the incubator's characteristics. Materials and methods: Six ADSCs cultures were isolated, frozen and stored to-1400C. Following thawing, cells underwent an endothelial differentiation protocol composed of a static and a dynamic phase, the latter requiring a water recirculation system created by us. Results: Over 100 million ADSCs were cultured and cryopreserved. Thawing tests reported over 80% viability. Five endothelial cell cultures were obtained, confirmed by immunohistochemistry. During the dynamic differentiation the incubator's environment was constant and stable. Conclusions: The system represents a viable option for dynamic conditioning in a normal cell culture incubator environment. We certificated it in ADSCs endothelial differentiation, replacing an expensive acquisition. [ABSTRACT FROM AUTHOR]

Objective: achieving a pulmonary valve xenograft with no hemodynamic impact. Methods: In the Tissue Engineering and Regenerative Medicine Laboratory at the University of Medicine and Pharmacy Tîrgu-Mureş, acellular scaffolds were created from decellularized porcine pulmonary valves using mechanical, chemical and enzymatic methods. Those were included in a decellularized bovine pericardium conduct and placed in extra-anatomic position between the right ventricle outflow tract and the pulmonary trunk. 7 juvenile sheep about 4-5 months (22-25 kg) were selected as animal model. Right ventricle and pulmonary artery invasive pressures were measured intra-operatorily, before and after the ligature of the native pulmonary trunk. Systemic blood pressure, heart rate and oxygen saturation were also monitored. Results: The physiologic average of the right ventricle mean pressure was 20.14 mmHg (interval between 17 and 22) and in the pulmonary artery, it was 23.42 mmHg (interval between 21 and 26). Redirecting the blood flow through the valvular conduit, by ligating the pulmonary trunk origin produced similar values: 21.42 mmHg (19 to 23) in the right ventricle and 23.14 mmHg (21 to 26) in the pulmonary artery. The new means were not significantly different from the native values, as shown by the two-tailed p values of the paired t-test (p = 0.06, respectively 0.77, at a 95% confidence level). Arterial blood pressures were maintained between 110-130/70-80 mmHg, heart rate below 100/min and oxygen saturation above 94%. Conclusions: Our pulmonary valve xenograft implantation technique did not modify intraventricular and pulmonary pressures. Systemic blood pressure, heart rate and oxygen saturation were also stable. Long term follow-up is necessary to evaluate the xenograft performance. [ABSTRACT FROM AUTHOR]