Fluid dwell impact induces peritoneal fibrosis in the peritoneal cavity reconstructed in vitro

Effect of aquaporin 1 on mouse peritoneal mesothelial cells after a long-term peritoneal dialysis

Aquaporin 1 (AQP1) is one member of the aquaporin family, also the deeply studied one. It is widely located on the endothelial cells, but the effect of AQP1 on the peritoneal mesothelial cells (PMCs) after long-term peritoneal dialysis (PD) has not been reported before. We divided normal mice into two groups, control group and dialysis group, to confirm the fibrotic changes and expression of APQ1 on peritoneal mesothelial cells. Then we assigned normal mice and AQP1 knockout mice into four groups: Control group, normal dialysis group, AQP1 knockout control group and AQP1 knockout dialysis group. The two dialysis groups received 4.25% glucose dialysis for 28 days. We found that mice in both dialysis groups showed peritoneal fibrotic changes, which were most severe in the AQP1 knockout dialysis group; the peritoneal thickness in the AQP1 knockout dialysis group was also thicker than that in the dialysis group (P < .05). We used electron microscopy to detect ultrastructural changes and observed changes in microvilli and vacuolar degeneration in mesothelial cells from all groups except the control group. The basement membranes were damaged in the AQP1 knockout dialysis group, and peritoneal mesothelial cells were disrupted and detached in this group. Together our findings indicate that AQP1 plays an important role in maintaining the physiological functions of peritoneal mesothelial cells, and AQP1 can protect mesothelial cells during dialysis.

Complex Determinants of Epithelial: Mesenchymal Phenotypic Plasticity in Ovarian Cancer

Unlike most epithelial malignancies which metastasize hematogenously, metastasis of epithelial ovarian cancer (EOC) occurs primarily via transcoelomic dissemination, characterized by exfoliation of cells from the primary tumor, avoidance of detachment-induced cell death (anoikis), movement throughout the peritoneal cavity as individual cells and multi-cellular aggregates (MCAs), adhesion to and disruption of the mesothelial lining of the peritoneum, and submesothelial matrix anchoring and proliferation to generate widely disseminated metastases. This exceptional microenvironment is highly permissive for phenotypic plasticity, enabling mesenchymal-to-epithelial (MET) and epithelial-to-mesenchymal (EMT) transitions. In this review, we summarize current knowledge on EOC heterogeneity in an EMT context, outline major regulators of EMT in ovarian cancer, address controversies in EMT and EOC chemoresistance, and highlight computational modeling approaches toward understanding EMT/MET in EOC.

Progress in cell culture systems for pathological research

Cell culture is a well-established standard technique and a fundamental tool in biology and medicine. Establishment of a novel culture method by meeting various challenges can sometimes open up new fields of cell biology and medicine. An artificial microenvironment for cultured cells is made up of complicated factors, including cytokines, scaffold material type, cell-cell interactions, and physical stress. To replicate the tissue architecture, cell-cell interactions, and specific physical microenvironment, we previously demonstrated the effectiveness of a three-dimensional culture system, and further established two simple culture systems: air-liquid interface (ALI) and fluid flow stress (FFS). A three-dimensional collagen gel culture system can replicate cell-cell interactions in vitro. As skin is constantly exposed to air, the ALI system closely mimicked the skin microenvironment and maintained the homeostasis of the epidermis and dermis. The ALI culture system also revealed the possibility of skin regeneration through ectopic mesenchymal cell involvement. Fluid streaming and shear stress were recently demonstrated to constitute the critical microenvironment for various cell types. The FFS system demonstrated that fluid streaming induced epithelial-mesenchymal transition of mesothelial cells, leading to peritoneal fibrosis. Our novel culture systems will hopefully open up new fields of regenerative medicine and pathological research.