Paper purpose: Xenografic heart valve decellularization using chemical and enzymatic agents represents the process through which extracellular matrix derived biomaterials – scaffolds are obtained. Scaffolds are tem-porary support structures with biologic (cell support) and mechanical (hemodynamic) role. These structu-res along with stem cells and bioreactors represent the tools with which regenerative medicine aims towards the ideal valvular substitute. In previous studies, in which we tried to decellularize pulmonary valves root by immersion, we observed in histological, qualitative examinations, the presence of some formations then interpreted as a cellular residue, requiring new methods to provide a perfectly acellular matrix. For this, a perfu-sion system was used adding a pressure gradient.
Material and method: This is part of a research grant that has the approval of the Ethics Committee of UMF Tirgu Mures. 11 pulmonary valves were included in the study. n=6 pulmonary valves underwent immersion decellularization protocol and n=5 were cyclically per-fused in a closed circuit and a 20-25 mmHg pressure gradient was applied in a 10-day protocol. The acellular valves thus obtained underwent a quality control using DAPI (4‘, 6-diamidino-2-phenylindol) nuclear stai-ning, histological haematoxylin-eosin, DNA extraction structural levels: arterial wall, sinus, cusp.
Results: Histological determinations highlighting the integrity of extracellular matrix in both valvular groups and the absence of cells at the level of the three val-vular structures analyzed. For the 5 VP decellularised by perfusion, there was a lack of identified formations within the other batch, thus interpreting those residues as potential residual nucleic material. The DNA extrac-tion procedure for VP following the perfusion protocol revealed non-measurable levels with the absence of mi-gration lines in gel electrophoresis.
Conclusions: T his decelularization protocol repre-sents a feasible way of obtaining acellular cardiac val-vular scaffolds derived from the extracellular matrix, resulting in superior results to the simple immersion decellularization method. Total absence of nucleic ma-terial underlines once again their non-immunogenic potential. The process is fast, allowing the production of a large number of valvular extracellular matrix deri-ved biomaterials in a short period of time.
Acknowledgement: T his work was supported by a grant from the Competitiveness Operational Program-me2014-2020, Tissue engineering technologies for cardiac valve regeneration, valve-regen, idP_37_673, Mysmis code:103431, contract50/05.09.2016.
Keywords: heart valve, acellular, decellularization, re-generative medicine