In vivo biocompatibility analysis of the recellularized canine tracheal scaffolds with canine epithelial and endothelial progenitor cells.

Decellularized extracellular matrix (ECM) has frequently been applied as a biomaterial for tissue engineering purposes. When implanted, their role can be essential for partial trachea replacement in patients that require a viable transplant solution. Acellular canine tracheal scaffolds with preserved ECM structure, flexibility, and proteins were obtained by high pressure vacuum decellularization. Here, we aimed to evaluate the cell adhesion and proliferation of canine tracheal epithelial cells (EpC) and canine yolk sac endothelial progenitor cells (YS) cultivated on canine decellularized tracheal scaffolds and test the in vivo biocompatibility of these recellularized scaffolds implanted in BALB-c nude mice. In order to evaluate the recellularization efficiency, scaffolds were evaluated by scanning electron microscopy (SEM), immunofluorescence, DNA quantification, mycoplasma test, and in vivo biocompatibility. The scaffolds sterility was confirmed, and EpC and YS cells were cultured by 7 and 14 days. We demonstrated by SEM, immunofluorescence, and genomic DNA analyzes cell adhesion to tracheal ECM. Then, recellularized scaffolds were in vivo subcutaneously implanted in mice and after 45 days, the fragments were collected and analyzed by Hematoxylin-Eosin and Gömori Trichrome staining and PCNA, CD4, CD8, and CD68 immunohistochemistry. In vivo results confirmed that the implanted tissue remains preserved and proliferative, and no fibrotic tissue process was observed in animals. Finally, our results showed the recellularization success due the preserved ECM proteins, and that these may be suitable to future preclinical studies applications for partial trachea replacement in tissue engineering.

Recellularized rat testis scaffolds with embryoid bodies cells: a promising approach for tissue engineering.

Tissue engineering is gaining use to investigate the application of its techniques for infertility treatment. The use of pluripotent embryonic cells for in vitro production of viable spermatozoa in testicular scaffolds is a promising strategy that could solve male infertility. Due to cell-extracellular matrix (ECM) interactions, here we aim to investigate the differentiation of embryoid bodies (EBs) in cultured into decellularized rat testis scaffolds. Decellularized testis (P = 0.019) with a low concentration of gDNA (30.58 mg/ng tissue) was obtained by sodium dodecyl sulfate perfusion. The structural proteins (collagens type I and III) and the adhesive glycoproteins of ECM (laminin and fibronectin) were preserved according to histological and scanning electron microscopy (SEM) analyses. Then, decellularized rat testis were cultured for 7 days with EB, and EB mixed with retinoic acid (RA) in non-adherent plates. By SEM, we observe that embryonic stem cells adhered in the decellularized testis ECM. By immunofluorescence, we verified the positive expression of HSD17B3, GDNF, ACRV-1, and TRIM-36, indicating their differentiation using RA in vitro, reinforcing the possibility of EB in male germ cell differentiation. Finally, recellularized testis ECM may be a promising tool for future new approaches for testicular cell differentiation applied to assisted reproduction techniques and infertility treatment.Abbreviations: ACRV-1: Acrosomal vesicle protein 1; ATB: Penicillin-streptomycin; DAPI: 4,6-Diamidino-2-phenylindole; EB: Embryoid bodies; ECM: Extracellular matrix; ESCs: Pluripotent embryonic stem cells; GAGs: Glycosaminoglycans; gDNA: Genomic DNA; GDNF: Glial cell line-derived neurotrophic factor; H&E: Hematoxylin and eosin; HSD17B3: 17-beta-Hydroxysteroid dehydrogenase type 3; PBS: Phosphate-buffered saline; PGCLCs: Primordial germ-cell-like cells; RA: Retinoic acid; SDS: Sodium dodecyl sulfate; SEM: Scanning electron microscopy; SSCs: Spermatogonial stem cells; TRIM-36: Tripartite Motif Containing 36.