The impact of albumin infusion on the risk of rebleeding and in-hospital mortality in cirrhotic patients admitted for acute gastrointestinal bleeding: a retrospective study of a single institute.

BACKGROUND: To investigate the effect of albumin infusion on cirrhotic patients admitted for acute gastrointestinal bleeding. METHODS: Medical records of cirrhotic patients who admitted due to acute gastrointestinal bleeding through January 2009 to December 2018 were reviewed. Clinical data and the total amount of albumin and red blood cell used during hospitalization were recorded. For patients with rebleeding, the amount of albumin and red blood cell used before rebleeding was also documented. The primary outcome was the occurrence of rebleeding, and the second outcome was in-hospital mortality. Univariate and multivariate logistic analysis was performed to identify risk factors associated with rebleeding and in-hospital mortality. RESULTS: A total of 1503 cirrhotic patients were included in the analysis. There were 146 episodes of in-patient rebleeding occurred, while 81 patients died. Overall, more red blood cells and albumin were prescribed to patients who suffered rebleeding. In terms of the amount before rebleeding, the red blood cell was higher in patients with rebleeding, but the albumin infusion was similar. In the multivariate model, the albumin infusion before rebleeding was an independent risk factor associated with rebleeding (adjusted OR for ≤40 g vs 0 g, 0.469 [0.269-0.793], p = 0.006; adjusted OR for > 40 g vs 0 g, 0.272 [0.115-0.576], p = 0.001). In Child-Pugh C class patients, the use of albumin more than 40 g during hospitalization associated with a lower risk of in-patient mortality (adjusted OR for > 40 g vs 0 g, 0.136 [0.019-0.741], p = 0.031). CONCLUSIONS: Albumin infusion was associated with a lower risk of rebleeding and in-hospital deaths in cirrhosis admitted for acute gastrointestinal bleeding.

Metabolic engineering of Pichia pastoris for the production of dammarenediol-II.

Dammarenediol-II is the nucleus of dammarane-type ginsenosides, which are a group of active triterpenoids exhibiting various pharmacological activities. Based on the native triterpene synthetic pathway, a dammarenediol-II synthetic pathway was established in Pichia pastoris by introducing a dammarenediol-II synthase gene (PgDDS) from Panax ginseng, which is responsible for the cyclization of 2,3-oxidosqualene to dammarenediol-II in this study. To enhance productivity, a strategy of "increasing supply and reducing competitive consumption of 2,3-oxidosqualene" was used. To increase the supply of 2,3-oxidosqualene, we augmented expression of the ERG1 gene, which is responsible for 2,3-oxidosqualene synthesis. This significantly improved the yield of dammarenediol-II over 6.7-fold, from 0.030mg/g dry cell weight (DCW) to 0.203mg/g DCW. Subsequently, to reduce competition for 2,3-oxidosqualene from ergosterol biosynthesis without affecting the normal growth of P. pastoris, we targeted the ERG7gene, which is responsible for conversion of 2,3-oxidosqualene to lanosterol. This gene was downregulated by replacing its native promoter with a thiamine-repressible promoter, using a marker-recycling and gene-targeting Cre- lox71/66 system developed for P. pastoris herein. The yield of dammarenediol-II was further increased more than 3.6-fold, to 0.736mg/g DCW. Furthermore, the direct addition of 0.5g/L squalene into the culture medium further enhanced the yield of dammarenediol-II to 1.073mg/g DCW, which was 37.5-fold higher than the yield from the strain with the PgDDS gene introduction only. The P. pastoris strains engineered in this study constitute a good platform for further production of ginsenosides in Pichia species.

Microvesicles derived from human umbilical cord mesenchymal stem cells stimulated by hypoxia promote angiogenesis both in vitro and in vivo.

Although mesenchymal stem cells (MSCs) have been increasingly trialed to treat a variety of diseases, the underlying mechanisms remain still elusive. In this study, human umbilical cord (UC)-derived MSCs were stimulated by hypoxia, and the membrane microvesicles (MVs) in the supernatants were collected by ultracentrifugation, observed under an electron microscope, and the origin was identified with the flow cytometric technique. The results showed that upon hypoxic stimulus, MSCs released a large quantity of MVs of ~100 nm in diameter. The MVs were phenotypically similar to the parent MSCs, except that the majority of them were negative for the receptor of platelet-derived growth factor. DiI-labeling assay revealed that MSC-MVs could be internalized into human UC endothelial cells (UC-ECs) within 8 h after they were added into the culture medium. Carboxyfluorescein succinimidyl ester-labeling technique and MTT test showed that MSC-MVs promoted the proliferation of UC-ECs in a dose-dependent manner. Further, MVs could enhance in vitro capillary network formation of UC-ECs in a Matrigel matrix. In a rat hindlimb ischemia model, both MSCs and MSC-MVs were shown to improve significantly the blood flow recovery compared with the control medium (P<0.0001), as assessed by laser Doppler imaging analysis. These data indicate that MV releasing is one of the major mechanisms underlying the effectiveness of MSC therapy by promoting angiogenesis.