Autophagy-modulated human bone marrow-derived mesenchymal stem cells accelerate liver restoration in mouse models of acute liver failure

Background: Mesenchymal stem cells [MSCs] have been recently received increasing attention for cell-based therapy, especially in regenerative medicine. However, the low survival rate of these cells restricts their therapeutic applications. It is hypothesized that autophagy might play an important role in cellular homeostasis and survival. This study aims to investigate the regenerative potentials of autophagy-modulated MSCs for the treatment of acute liver failure [ALF] in mice

Methods: ALF was induced in mice by intraperitoneal injection of 1.5 ml/kg carbon tetrachloride. Mice were intravenously infused with MSCs, which were suppressed in their autophagy pathway. Blood and liver samples were collected at different intervals [24, 48 and 72 h] after the transplantation of MSCs. Both the liver enzymes and tissue necrosis levels were evaluated using biochemical and histopathological assessments. The survival rate of the transplanted mice was also recorded during one week

Results: Biochemical and pathological results indicated that 1.5 ml/kg carbon tetrachloride induces ALF in mice. A significant reduction of liver enzymes and necrosis score were observed in autophagy-modulated MSC-transplanted mice compared to sham [with no cell therapy] after 24 h. After 72 h, liver enzymes reached their normal levels in mice transplanted with autophagy-suppressed MSCs. Interestingly, normal histology without necrosis was also observed

Conclusion: Autophagy suppression in MSCs ameliorates their liver regeneration potentials due to paracrine effects and might be suggested as a new strategy for the improvement of cell therapy in ALF

[ effects of waterpipe smoke and darkness stress on serum creatine kinase and alkaline phosphatase levels in female rats]

There is an association between life style and serum levels of certain enzymes. This study aims to determine the effects of waterpipe smoke and darkness stress on serum levels of creatine kinase and alkaline phosphatase in female rats. In this experimental study, female Wistar rats were randomly divided into control, waterpipe smoke receiving, under darkness stress and both under darkness stress and warerpipe smoke receiving groups of 7 rats in each. Waterpipe smoke receiving rats were exposed to waterpipe smoke for 100 min/day and animals under darkness stress exposed to 5 hours darkness during the day. Under darkness stress and warerpipe smoke receiving animals were exposed to both waterpipe smoke for 100 min/day and 5 hours darkness during the day. After 7 weeks, blood samples were collected and serum alkaline phosphatase and creatine kinase levels were measured by spectrophotometry. The data were analysed using ANOVA. The serum creatine kinase and alkaline phosphatase levels significantly increased in waterpipe smoke receiving, under darkness stress and both under darkness stress and waterpipe smoke receiving rats compared to control animals [p<0.001 and p<0.05, respectively]. Also there was significant difference in creatine kinase and alkaline phosphatase levels between waterpipe smoke receiving and under darkness stress rats [p<0.001 and p<0.05, respectively]. The serum levels of creatine kinase and alkaline phosphatase were significantly higher in waterpipe smoke receving rats compared to under darkness stress animlas [p<0.001and p<0.05, respectively]. Our findings indicated that waterpipe smoke and darkness stress lead to increased serum levels of creatine kinase and alkaline phosphatase; according to which, these factors can impose serious pathophysiological effects on internal organs including heart, brain, liver or muscles

effects of co-administration of immobilization stress and aloe vera on serum carcinoembryonic antigen in rats

Immobilization has been used extensively and accepted widely for studying stress-induced alterations. To determine the protective effects of Aloe vera leaf extract, we evaluated the effects of co-administration of immobilization stress and Aloe vera leaf extract on serum level of carcinoembryonic antigen [CEA] tumor marker in male rats. In this experimental study, 45 male Wistar rats were randomly divided into 9 groups of 5 rats in each including: 1] control, 2] normal saline receiving, 3] Aloe vera extract receiving, 4] acutely immobilized, 5] chronically immobilized, 6] acutely immobilized+Aloe vera extract, 7] chronically immobilized+Aloe vera extract, 8] acutely immobilized+normal saline and 9] chronically immobilized + normal saline. The animals were exposed to chronic or acute immobilization stress for 2 h/day or 8 h/day for a period of 3 weeks or one week, respectively. Aloe vera extract [300 mg/kg/day] was fed by gavage feeding orally. Blood samples were collected and following serum collection, CEA level was determined by radioimmunoassay method. Data were compared statistically between groups using ANOVA. Serum CEA level was significantly increased in acutely [0.640 +/- 0.025 ng/mL] or chronically immobilized [0.647 +/- 0.023 ng/mL] rats compared with control animals group [0.564 +/- 0.014 ng/mL] [p<0.001]. However, there was no significant difference between serum CEA levels of acutely or chronically immobilized Aloe vera extract received animals compared with control rats [0.622 +/- 0.027 ng/m and 0.616 +/- 0.044 ng/mL, respectively]. Our findings indicate that immobilization stress enhances serum CEA level, however, intake of Aloe vera extract can withstand against

Down-regulation of the autophagy gene, ATG7, protects bone marrow-derived mesenchymal stem cells from stressful conditions

BACKGROUND: Mesenchymal stem cells (MSCs) are valuable for cell-based therapy. However, their application is limited owing to their low survival rate when exposed to stressful conditions. Autophagy, the process by which cells recycle the cytoplasm and dispose of defective organelles, is activated by stress stimuli to adapt, tolerate adverse conditions, or trigger the apoptotic machinery. This study aimed to determine whether regulation of autophagy would affect the survival of MSCs under stress conditions. METHODS: Autophagy was induced in bone marrow-derived MSCs (BM-MSCs) by rapamycin, and was inhibited via shRNA-mediated knockdown of the autophagy specific gene, ATG7. ATG7 expression in BM-MSCs was evaluated by reverse transcription polymerase chain reaction (RT-PCR), western blot, and quantitative PCR (qPCR). Cells were then exposed to harsh microenvironments, and a water-soluble tetrazolium salt (WST)-1 assay was performed to determine the cytotoxic effects of the stressful conditions on cells. RESULTS: Of 4 specific ATG7-inhibitor clones analyzed, only shRNA clone 3 decreased ATG7 expression. Under normal conditions, the induction of autophagy slightly increased the viability of MSCs while autophagy inhibition decreased their viability. However, under stressful conditions such as hypoxia, serum deprivation, and oxidative stress, the induction of autophagy resulted in cell death, while its inhibition potentiated MSCs to withstand the stress conditions. The viability of autophagy-suppressed MSCs was significantly higher than that of relevant controls (P<0.05, P<0.01 and P<0.001). CONCLUSION: Autophagy modulation in MSCs can be proposed as a new strategy to improve their survival rate in stressful microenvironments.