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.

Bacterial translocation contributes to cachexia and its possible pathway in patients with colon cancer.

GOALS AND BACKGROUND: There is increasing evidence that bacterial translocation (BT) might contribute to the occurrence and development of cancer cachexia, but the detailed mechanism remains unknown. Thus, we undertook further investigations into the association of BT with cancer cachexia and the possible pathway. STUDY: The colon cancer patients enrolled in this study were divided into cachectic and noncachectic. BT was analyzed by polymerase chain reaction and bacterial culture. Intestinal epithelial T-cell subsets and NK cells were evaluated using flow cytometry. Western blotting and immunofluorescence were used to check tight junction (TJ) proteins in intestinal epithelium. Fluorescence in situ hybridization and immunohistochemistry were used to detect the translocated bacteria and endotoxin. RESULTS: Compared with noncachectic patients, cachectic patients had a significantly higher BT ratio (P<0.001). We observed the translocated bacteria in the intestinal mucus layer associated with lower levels of T-cell subsets and NK cells in the intestinal epithelium in BT-positive patients (P<0.05). Endotoxin was detected within the small intestinal wall and the concentration of endotoxin decreased from the mucosal side to serosal side gradually in these patients. These were associated with an altered composition of TJs. CONCLUSIONS: This study suggests that BT may contribute to colon cancer in cachectic patients, and TJ could be the gateway to the possible pathway of BT.

Expression patterns of tight junction components induced by CD24 in an oral epithelial cell-culture model correlated to affected periodontal tissues.

BACKGROUND AND OBJECTIVE: Previously we demonstrated uniformly strong expression of CD24 in the epithelial attachment to the tooth and in the migrating epithelium of the periodontitis lesion. Titers of serum antibodies autoreactive with CD24 peptide correlated with reduced severity of periodontal disease. Ligation of CD24 expressed by oral epithelial cells induced formation of tight junctions that limited paracellular diffusion. In this study, we aimed to reveal that the lack of uniform expression of tight junction components in the pocket epithelium of periodontitis lesions is likely to contribute to increased paracellular permeability to bacterial products. This is proposed as a potential driver of the immunopathology of periodontitis. MATERIAL AND METHODS: An epithelial culture model with close correspondence for expression patterns for tight junction components in periodontal epithelia was used. Immunohistochemical staining and confocal laser scanning microscopy were used to analyse patterns of expression of gingival epithelial tight junction components. RESULTS: The minimally inflamed gingival attachment was characterized by uniformly strong staining at cell contacts for the tight junction components zona occludens-1, zona occludens-2, occludin, junction adhesion molecule-A, claudin-4 and claudin-15. In contrast, the pocket epithelium of the periodontal lesion showed scattered, uneven staining for these components. This pattern correlated closely with that of unstimulated oral epithelial cells in culture. Following ligation of CD24 expressed by these cells, the pattern of tight junction component expression of the minimally inflamed gingival attachment developed rapidly. CONCLUSION: There was evidence for non-uniform and focal expression only of tight junction components in the pocket epithelium. In the cell-culture model, ligation of CD24 induced a tight junction expression profile equivalent to that observed for the minimally inflamed gingival attachment. Ligation of CD24 expressed by gingival epithelial cells by lectin-like receptors of commensal oral streptococci could mediate the phenotype of health, whereas pathogenic organisms associated with periodontal disease might not signal effectively through CD24.