Ex vivo construction of a novel model of bioengineered bladder mucosa: A preliminary study.
OBJECTIVE
To generate and to evaluate ex vivo a novel model of bioengineered human bladder mucosa based on fibrin-agarose biomaterials.


METHODS
We first established primary cultures of stromal and epithelial cells from small biopsies of the human bladder using enzymatic digestion and selective cell culture media. Then, a bioengineered substitute of the bladder lamina propria was generated using cultured stromal cells and fibrin-agarose scaffolds, and the epithelial cells were then subcultured on top to generate a complete bladder mucosa substitute. Evaluation of this substitute was carried out by cell viability and histological analyses, immunohistochemistry for key epithelial markers and transmission electron microscopy.


RESULTS
The results show a well-configured stroma substitute with a single-layer epithelium on top. This substitute was equivalent to the control bladder mucosa. After 7 days of ex vivo development, the epithelial layer expressed pancytokeratin, and cytokeratins CK7, CK8 and CK13, as well as filaggrin and ZO-2, with negative expression of CK4 and uroplakin III. A reduction of the expression of CK8, filaggrin and ZO-2 was found at day 14 of development. An immature basement membrane was detected at the transition between the epithelium and the lamina propria, with the presence of epithelial hemidesmosomes, interdigitations and immature desmosomes.


CONCLUSIONS
The present results suggest that this model of bioengineered human bladder mucosa shared structural and functional similarities with the native bladder mucosa, although the epithelial cells were not fully differentiated ex vivo. We hypothesize that this bladder mucosa substitute could have potential clinical usefulness after in vivo implantation.
Department of Histology (Tissue Engineering Group), University of Granada, Granada, Spain.|Biomedical Research Institute, University of Granada, Granada, Spain.|PhD Program in Biomedicine, University of Granada, Granada, Spain.
Boris D
BD
Jaimes-Parra
Department of Urology, Hospital San Juan de la Cruz, Jaen, Spain.
Francisco
F
Valle-Díaz de la Guardia
Urology Department, Hospital La Inmaculada, Almeria, Spain.
Miguel Á
MÁ
Arrabal-Polo
Division of Urology and Urology Unit Research, Virgen de la Victoria Hospital, Malaga, Spain.
Bernardo
B
Herrera-Imbroda
Division of Urology and Urology Unit Research, Virgen de la Victoria Hospital, Malaga, Spain.
María F
MF
Lara
Division of Urology and Urology Unit Research, Virgen de la Victoria Hospital, Malaga, Spain.
Francisco-Javier
FJ
Machuca-Santa-Cruz
Department of Histology (Tissue Engineering Group), University of Granada, Granada, Spain.|Biomedical Research Institute, University of Granada, Granada, Spain.
Antonio
A
Campos
Department of Histology (Tissue Engineering Group), University of Granada, Granada, Spain.|Biomedical Research Institute, University of Granada, Granada, Spain.
Miguel
M
Alaminos
Department of Histology (Tissue Engineering Group), University of Granada, Granada, Spain.|Biomedical Research Institute, University of Granada, Granada, Spain.
Pascual V
PV
Crespo
Department of Histology (Tissue Engineering Group), University of Granada, Granada, Spain.|Biomedical Research Institute, University of Granada, Granada, Spain.
Ingrid
I
Garzón
D000328:Adult; D000368:Aged; D001485:Basement Membrane / Q000648:ultrastructure; D001672:Biocompatible Materials; D002470:Cell Survival; D004847:Epithelial Cells; D005337:Fibrin; D000091344:Filaggrin Proteins; D006801:Humans; D007381:Intermediate Filament Proteins / Q000032:analysis; D053535:Keratin-13 / Q000032:analysis; D053527:Keratin-4 / Q000032:analysis; D053552:Keratin-7 / Q000032:analysis; D053533:Keratin-8 / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000737:chemistry / Q000166:cytology* / Q000648:ultrastructure; D061251:Primary Cell Culture; D012685:Sepharose; D017154:Stromal Cells; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D001743:Urinary Bladder / Q000166:cytology*; D060171:Uroplakin III / Q000032:analysis; D062827:Zonula Occludens-2 Protein / Q000032:analysis
D001672:Biocompatible Materials; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D053535:Keratin-13; D053527:Keratin-4; D053552:Keratin-7; D053533:Keratin-8; C569046:TJP2 protein, human; D060171:Uroplakin III; D062827:Zonula Occludens-2 Protein; D005337:Fibrin; D012685:Sepharose
bladder mucosa; cytokeratins; fibrin-agarose; tissue engineering