O44 – Transforming growth factor beta induced epithelial-mesenchymal transition leads to persistent intestinal fistulae
Author(s):
Background: Autologous glue can lessen closure times and promote closure rates in treatment of low-output enterocutaneous fistulas (ECFs). Factors affecting outcomes of the glue-assisted closure (GAC), however, were not clear.
Hypothesis: The GAC-failed ECF might have a prolonged inflammatory phase modulated by excessive pro-inflammatory cytokines or proteases.
Methods: A hospital based case-control study was performed. Blood samples and fistula tissues were collected before the autologous glue application. Protein or mRNA levels of biological markers (IL-6, IL-1β, TNF-α, IL-8, IL-10, GM-CSF, and TGF-β) were studied by multiplex xMAP immunoassay or real-time PCR. Those GAC-failed fistula patients turned to definite operations and surgical removed specimens were further analyzed by hematoxylin and eosin staining, and immunohistochemistry.
Results: A total of 22 ECF patients with low-output volume were enrolled for the glue application. Elevated levels of pro-inflammatory cytokines (GM-CSF, IL-1β, IL-6, and TNFα), but decreased levels of anti-inflammatory cytokines (IL-8 and IL-10) from plasmas as well as tissue samples were observed in GAC-failed fistulas (P>0.05). Only TGF-β was significantly higher in open fistulas among all cytokines (P<0.05). Besides, strong staining for β6-integrin, the mesenchymal marker, was found in transitional cells lining the tracts of surgically resected fistulas and in epithelial cells of deformed crypts adjacent to the fistulas.
Conclusions: TGF-β was associated the failure of GAC and provided a further hint that the growth factor was responsible for the epithelial to mesenchymal transition (EMT). Therefore, we speculated that EMT might take place in and around the majority of these GAC-failed fistulas.