Protection of ghrelin postconditioning on hypoxia/reoxygenation in gastric epithelial cells.

AIM: To investigate the protective effect and mechanisms of ghrelin postconditioning against hypoxia/reoxygenation (H/R)-induced injury in human gastric epithelial cells. METHODS: The model of H/R injury was established in gastric epithelial cell line (GES-1) human gastric epithelial cells. Cells were divided into seven groups: normal control group (N); H/R postconditioning group; DMSO postconditioning group (DM); ghrelin postconditioning group (GH); D-Lys3-GHRP-6 + ghrelin postconditioning group (D + GH); capsazepine + ghrelin postconditioning group (C + GH); and LY294002 + ghrelin postconditioning group (L + GH). 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to detect GES-1 cell viability. Hoechst 33258 fluorochrome staining and flow cytometry were conducted to determine apoptosis of GES-1 cells. Spectrophotometry was performed to determine release of lactate dehydrogenate (LDH). Protein expression of Bcl-2, Bax, Akt, and glycogen synthase kinase (GSK)-3ß was determined by western blotting. Expression of vanilloid receptor subtype 1 (VR1), Akt and GSK-3ß was observed by immunocytochemistry. RESULTS: Compared with the H/R group, cell viability of the GH group was significantly increased in a dose-dependent manner (55.9% ± 10.0% vs 69.6% ± 9.6%, 71.9% ± 17.4%, and 76.3% ± 13.3%). Compared with the H/R group, the percentage of apoptotic cells in the GH group significantly decreased (12.38% ± 1.51% vs 6.88% ± 0.87%). Compared with the GH group, the percentage of apoptotic cells in the D + GH group, C + GH group and L + GH groups significantly increased (11.70% ± 0.88%, 11.93% ± 0.96%, 10.20% ± 1.05% vs 6.88% ± 0.87%). There were no significant differences in the percentage of apoptotic cells between the H/R and DM groups (12.38% ± 1.51% vs13.00% ± 1.13%). There was a significant decrease in LDH release following ghrelin postconditioning compared with the H/R group (561.58 ± 64.01 U/L vs 1062.45 ± 105.29 U/L). There was a significant increase in LDH release in the D + GH, C + GH and L + GH groups compared with the GH group (816.89 ± 94.87 U/L, 870.95 ± 64.06 U/L, 838.62 ± 118.45 U/L vs 561.58 ± 64.01 U/L). There were no significant differences in LDH release between the H/R and DM groups (1062.45 ± 105.29 U/L vs 1017.65 ± 68.90 U/L). Compared with the H/R group, expression of Bcl-2 and Akt increased in the GH group, whereas expression of Bax and GSK-3ß decreased. Compared with the GH group, expression of Bcl-2 decreased and Bax increased in the D + GH, C + GH and L + GH groups, and Akt decreased and GSK-3ß increased in the L + GH group. The H/R group also upregulated expression of VR1 and GSK-3ß and downregulated Akt. The number of VR1-positive and Akt-positive cells in the GH group significantly increased, whereas the number of GSK-3ß-positive cells significantly decreased. These effects of ghrelin were reversed by capsazepine and LY294002. CONCLUSION: Ghrelin postconditioning protected against H/R-induced injury in human gastric epithelial cells, which indicated that this protection might be associated with GHS-R, VR1 and the PI3K/Akt signaling pathway.

Recombinant human hepatocyte growth factor for liver failure.

The purpose of this paper is to evaluate the efficacy and safety of recombinant human hepatocyte growth factor (rh-HGF) for liver failure (LF) using meta-analysis of data from the literature involving available randomized controlled trials of rh-HGF plus comprehensive therapy (CT) compared with that of CT alone (Therapy I versus II) in treating LF. We searched the Cochrane Library, MEDLINE, EMBASE, CBMdisc, and CNKI as well as employing manual searches. Based on our search criteria, we found 21 trials, involving 5902 patients. Our results showed that Therapy I, compared with therapy II, significantly reduced the overall mortality (RR=0.62; 95% CI, 0.59-0.66; p=0.0001). Compared to two clinical types of LF (acute and acute-on-chronic), therapy I perhaps had significant effect on mortality due to sub-acute LF, RR and 95% CI were 0.76 [0.65, 0.89], 0.66 [0.60, 0.74], and 0.58 [0.53, 0.64], respectively. Additionally, there was a reduction in mortality of patients that had evidence for an early stage of LF compared to the two other clinical stages of LF (Middle and Advanced); RR and 95% CI were 0.34 [0.24, 0.49], 0.49 [0.44, 0.55], and 0.87 [0.82, 0.93], respectively. No serious adverse events were reported. We conclude that Therapy I may reduce mortality in LF, especially in sub-acute LF and the early stage of LF. However, considering the strength of the evidence, additional randomized controlled trials are needed before Therapy I can be recommended routinely.