RESUMO
Long-term experiments using organoids and tissues are crucial for drug development. Microfluidic devices have been regularly used in long-term experiments. However, microbubbles often form in these devices, and they may damage and starve cells. A method involving the application of negative pressure has been reported to remove microbubbles from microfluidic devices composed of polydimethylsiloxane; however, negative pressure affects the cells and tissues in microfluidic devices. In this study, a local microbubble removal method was developed using a microfluidic device with 0.5 mm thin polydimethylsiloxane sidewalls. The thin sidewalls counterbalanced the negative and atmospheric pressures, thereby localizing the negative pressure near the negatively pressurized chamber. Microbubbles were removed within 5 mm of the negatively pressurized chamber; however, those in an area 7 mm and more from the chamber were not removed. Using the local removal method, a long-term perfusion test was performed, and no contact was confirmed between the bubbles and the simulated tissue for 72 h.
RESUMO
Tissue assays have improved our understanding of cancers in terms of the three-dimensional structures and cellular diversity of the tissue, although they are not yet well-developed. Perfusion culture and active chemical gradient formation in centimeter order are difficult in tissue assays, but they are important for simulating the metabolic functions of tissues. Using microfluidic technology, we developed an H-shaped channel device that could form a long concentration gradient of molecules in a tissue that we could then analyze based on its appearance and content. For demonstration, a cylindrical pork tissue specimen was punched and equipped in the H-shaped channel device, and both ends of the tissue were exposed to flowing distilled and blue-dyed water for 100 h. After perfusion, the tissue was removed from the H-shaped channel device and sectioned. The gradient of the blue intensity along the longitudinal direction of the tissue was measured based on its appearance and content. We confirmed that the measured gradients from the appearance and content were comparable.
RESUMO
Non-alcoholic fatty liver disease (NAFLD) represents one of the most common causes of chronic liver disease worldwide and is characterized by chronic liver inflammation and fibrosis leading to cirrhosis and increased risk of liver cancer in a proportion of patients. Effective anti-fibrotic agents have yet to be approved for the treatment of NAFLD. The present study aimed to evaluate the efficacy of dipeptidyl peptidase 4 inhibitors (DPP4-I) in the prevention of NAFLD progression in NAFLD patients with type 2 diabetes. The study was a single arm, multi-centre, non-randomised study of NAFLD patients with type 2 diabetes. NAFLD was diagnosed according to ultrasonographic findings. All the patients received 25 mg/day of alogliptin for 12 months. The efficacy of alogliptin in preventing NAFLD progression was assessed using overall NAFIC scores [non-alcoholic steatohepatitis (NASH), ferritin, insulin and type IV collagen 7S] and individual component scores according to baseline haemoglobin A1c (HbA1c) levels. Of the 39 patients enrolled in the study, 16 patients (40.3%) had NAFIC scores >2 points, indicating the presence of NASH. NAFIC scores markedly decreased following 12 months of alogliptin administration, but remained >2 points in 10 patients, indicating that NASH may have persisted in these patients. The relative risks for persistent NASH were 4.92 (95% confidence interval, 0.61-40.0) in the highest HbA1c tertile group compared with those in the lowest group. However, no statistically significant linear trend was observed across all HbA1c categories (P=0.145). DPP4-I may have efficacy against NAFLD progression in patients with type 2 diabetes with relatively lower HbA1c levels. DPP4-I may represent a potential new therapeutic strategy for the prevention of disease progression in NAFLD patients with type 2 diabetes.