## 2 Materials and Methods
### Cultivation Bioreactor  
A custom-made dynamic culture system was used for recellularization of the decellularized tissue. This system consists of a specially designed cultivation chamber that allows fixing the pericardium, and of a pressure stimulation system generating pressure pulsation and culture media perfusion. The cultivation chamber consists of four main parts. The middle two parts create a tissue holder. Both parts create reservoirs for culture media, and also, one part contains a small silicone gasket fixing the tissue. The decellularized tissue is cut to \(35\times 35\) mm\({}^{2}\) squares. Then these squares are placed over the hole of the reservoir. The reservoir has a square shape and is limiting the area to \(30\times 30\) mm\({}^{2}\) where cells are cultivated. The remaining 2.5 mm border of the prepared tissues is used for fixing them in place. A special inlet is put into this hole in order to prevent tissue bending. Then, the tissue is fixed with the second middle part of the chamber containing the silicone gasket that fixes the tissue in its position. A silicone O-ring gasket is also added to ensure the tightness of the chamber. Four stainless steel M4 screws tighten the holder. After this procedure, the helping inlet is removed. Next, the chamber is closed by covers containing fluidics ports. Two more silicone O-ring gaskets are added to ensure the tightness. These covers are also tightened to the holder using stainless steel M4 screws with knurled nuts. To minimize the risk of any contamination or toxicity, these screws are not in contact with the tissue or the culture media. All other parts of the chamber are made of non-toxic materials including polycarbonate, polyamide, or silicone as mentioned above, and were \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**CD Marker** & **PrASC Animal 1** & **PrASC Animal 2** & **Antibody Provider** & **Cat. No.** \\ \hline
29 & 98.85\% & 99.34\% & Invitrogen (CA, USA) & CD2920 \\
31 & 34.58\% & 28.64\% & Origene (MD, USA) & SM2146 APC \\
34 & 0.47\% & 1.06\% & Biorbyt (UK) & orb247244 \\
45 & 1.09\% & 2.99\% & Biorad (CA, USA) & MCA1222A647 \\
73 & 0.31\% & 2.60\% & Biolegend (CA, USA) & 344004 \\
90 & 99.08\% & 99.64\% & BD Biosciences (NJ, USA) & 55596 \\
105 & 96.23\% & 99.56\% & Abcam (UK) & ab53321 \\
146 & 0.18\% & 0.71\% & Origene (MD, USA) & SM1860F \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Flow cytometry analysis of isolated adipose-derived stromal cells. previously tested for potential cytotoxicity. Fluidics ports include two elbow pieces with silicone hoses with Luer-Locks (LLs) or quick couplings for connecting the perfusion/stimulation system. There are also two female LLs located in the middle of the lid for connecting a sterile septum for cell seeding, auxiliary hoses for pressure sensing, etc. The overall view of the cultivation chamber and its sections are illustrated in Figure 2. The technical solution is described in detail in our utility model [24]. After assembling the chamber and ensuring its tightness, the chamber is connected to a perfusion circuit, a syringe with cultivation media and a working reservoir (described below). All the above-mentioned steps (i.e., tissue fixing, chamber assembling, connecting to perfusion circuit, etc.) are done in a biohazard box to ensure sterility. The cell seeding is then done using the sterile septum and a syringe with a needle. The chamber is vertically oriented during cultivation to minimize the risk of forming bubbles in the reservoirs. In order to provide multiple parallel sample cultivation, the chambers were daisy-chained. In order to maintain the perfusion of the tissue with cultivation media and to establish the stimulation of cells with pulsatile pressure waves, a unique system was also developed. This system is based on an electronically controlled linear actuator with the syringe and perfusion circuit connecting.