Patient-derived and artificial ascites have minor effects on MeT-5A mesothelial cells and do not facilitate ovarian cancer cell adhesion

The presence of ascites in the peritoneal cavity leads to morphological and functional changes of the peritoneal mesothelial cell layer. Cells loose cell-cell interactions, rearrange their cytoskeleton, activate the production of fibronectin, and change their cell surface morphology in a proinflammatory environment. Moreover, ovarian cancer cell adhesion has been shown to be facilitated by these changes due to increased integrin- and CD44-mediated binding sites. In this study, the biological responsiveness of the human pleural mesothelial cell line MeT-5A to patient-derived and artificial ascites was studied in vitro and adhesion of ovarian cancer cells, i.e. SKOV-3 cells, investigated. Changes were mainly observed in cells exposed to artificial ascites containing higher cytokine concentrations than patient-derived ascites. Interestingly, reduced cell-cell interactions were already observed in untreated MeT-5A cells and effects on tight junction protein expression and permeability upon exposure to ascites were minor. Ascites induced upregulation of CDC42 effector protein 2 expression, which affects stress fiber formation, however significant F-actin reorganization was not observed. Moreover, fibronectin production remained unchanged. Analysis of mesothelial cell surface characteristics showed upregulated expression of intercellular adhesion molecule 1, slightly increased hyaluronic acid secretion and decreased microvillus expression upon exposure to ascites. Nevertheless, the observed changes were not sufficient to facilitate adhesion of SKOV-3 cells on MeT-5A cell layer. This study revealed that MeT-5A cells show a reduced biological responsiveness to the presence of ascites, in contrast to published studies on primary human peritoneal mesothelial cells.

Value of artificial ascites to assist thermal ablation of liver cancer adjacent to the gastrointestinal tract in patients with previous abdominal surgery

Background To evaluate the feasibility and effectiveness of artificial ascites to assist thermal ablation of liver cancer adjacent to the gastrointestinal tract in patients with previous abdominal surgery. Methods Thirty-nine patients with a total of 40 liver malignant tumors were enrolled between January 2016 and June 2019. All had histories of hepatectomy, splenectomy, cholecystectomy, and intestinal surgery. The distance between the tumor and the gastrointestinal tract was < 5 mm. Normal saline was used as artificial ascites to protect the gastrointestinal tract during thermal ablation. The success rate of the procedure, incidence of major complications, and the technical efficacy of ablation were recorded. Patients were followed for local tumor progression (LTP), and overall survival (OS). Results The use of artificial ascites was successful in 38 of the 40 procedures (95%). Major complications occurred in two of the 39 patients (5.1%) following the procedure. One was an intestinal fistula that occurred in a failed case and was associated with an infection. The other was a liver abscess that occurred in a successful case. The technical efficacy of ablation was 100% (40/40 procedures). The median follow-up was 16 months. The 1-, 2-, and 3-year LTP rates were 2.9%, 5.7% and 5.7%. The 1-, 2-, and 3-year OS rates were 97.1%, 86.8% and 69.5%. Conclusion In patients with previous abdominal surgery, artificial ascites is feasible and effective for assisting thermal ablation of liver cancer adjacent to the gastrointestinal tract.