In vitro and in vivo assay of the ER lipid scramblase TMEM41B.

Amphipathic phospholipids translocated by scramblases play a central role in facilitating lipid movement across the membrane bilayer, especially at the endoplasmic reticulum (ER) membranes. Here, we present a protocol for assessing the activity of the ER-localized lipid scramblase TMEM41B. We detail an in vitro fluorescent liposome-based phospholipid scrambling assay and in vivo metabolic labeling in living cells using alkyne-choline. The scramblase activity of other VTT (VMP1, TMEM41, and Tvp38) domain-containing proteins, such as TMEM41A and VMP1, can be assayed. For complete details on the use and execution of this protocol, please refer to Huang et al. (2021).

Enzymatic synthesis of hydrophilic phytosterol polyol esters and assessment of their bioaccessibility and uptake using an in vitro digestion/Caco-2 cell model.

A novel enzyme-catalyzed method was developed for the synthesis of phytosterol polyol esters from ß-sitosterol and polyols (sorbitol, mannitol and xylitol) by two-step transesterification using divinyl adipate (DVA) as a link. A high conversion (exceeding 94%) of ß-sitosterol with a vinyl group was achieved, in the presence of Candida rugosa lipase (CRL), at low temperature (35 °C) within 30 min. Subsequently, the maximum conversion of phytosterol polyol esters (>94%) was obtained using alkaline protease from Bacillus subtilis at 65 °C. Phytosterol polyol esters had enhanced thermal stability (up to an above 355 °C) and excellent water solubility (4.6-7.9 mM at 35 °C). Moreover, obvious increases in the bioaccessibility (41.5-63.6%) and intestinal uptake (5.2-6.5%) were observed using a simulated gastrointestinal digestion/Caco-2 cell model. These results highlighted the key role of hydrophilic structural modifications on physicochemical properties and absorption of phytosterols.

A study of the differentiation of stem cells from human exfoliated deciduous teeth on 3D silk fibroin scaffolds using static and dynamic culture paradigms.

Stem cells from human exfoliated deciduous teeth (SHED) are considered the best current source of human stem cells due to their ability to differentiate into multiple cell lineages. Dynamic co-culture systems can improve the culture environment, as they provide cells with signaling factors, extracellular matrixes, and cellular shear force, as well as enable the formation of heterotypic clusters. We seeded SHED in 3D silk fibroin porous scaffolds under static and dynamic cultures for 28 days, using the NIH3T3 cultivated medium as an induction agent. Many hepatospheres formed in these porous scaffolds, and cellular viability was shown to continually increase by MTT assays. Hepatic AFP and ALB gene expression, as well as glycogen storage, albumin secretion, and urea synthesis, were greater in cells in the 3D porous scaffold under a dynamic culture than in those cultured under 3D static culture and petri dish conditions. However, the 3D static culture is still superior to the traditional petri dish culture. The NIH3T3 cultivated medium can significantly induce hepatic differentiation of SHED, while the 3D dynamic culture system significantly enhances hepatic differentiation of SHED. This study provides alternative sources of hepatocytes for liver disease treatment.

Stem cells from human exfoliated deciduous teeth differentiate into functional hepatocyte-like cells by herbal medicine.

Stem cells from human exfoliated deciduous teeth (SHEDs) are mesenchymal stem cells isolated from the exfoliated human deciduous incisor that can differentiate into a many cell types. In this study, we evaluated the effect of liquorice or angelica extracts on the hepatic differentiation potential of SHEDs cells. SHEDs cells cultured in medium containing liquorice extracts were analyzed for 1) changes in cellular morphology, 2) changes in hepatic gene expression, AFP (Alpha-fetoprotein) and ALB (Albumin), and 3) albumin secretion and urea synthesis activity. Our data show that the hepatic differentiation potential of SHEDs cells is enhanced by the presence of liquorice or angelica extracts in the culture medium. Our findings present new therapeutic possibilities for liver damage repair.

Metal versus plastic stents for malignant biliary obstruction: an update meta-analysis.

BACKGROUND AND OBJECTIVE: The data on comparisons of stent patency, re-intervention rate and patient survival between metal and plastic stents in palliation of malignant biliary obstruction have never been pooled. We carry out a meta-analysis to summarise current evidence for clinical efficacy of metal and plastic stents in the treatment of malignant biliary obstruction. METHODS: A comprehensive search of several databases was conducted. A fixed-effects or random-effects model was used to pool data of all study endpoints. Sensitivity analysis and subgroup analysis (distal vs. hilar biliary obstruction) were also performed. RESULTS: Ten randomized clinical trials were identified. Compared with plastic stents, metal stents were associated with a significantly longer stent patency (HR=0.36; 95% CI: 0.28-0.47; I(2)=0%), fewer numbers of re-intervention (WMD=0.59; 95% CI: 0.28-0.90; I(2)=76.4%) and longer patient survival (HR=0.74; 95% CI: 0.64-0.85; I(2)=16.0%). These results were still significant by sensitivity analysis. All outcomes reached statistical significance except of the pooled WMD of number of re-intervention in the studies with hilar biliary obstruction. No publication bias was observed. CONCLUSIONS: Metal stents were associated with a significantly longer stent patency, lower re-intervention rate and longer patient survival in palliation of malignant biliary obstruction when compared to plastic stents.