Lin28 promoting the protective effect of PMSCs on hepatic ischaemia-reperfusion injury by regulating glucose metabolism

Human placental mesenchymal stem cells (PMSCs) can prevent liver ischaemia-reperfusion injury (LIRI). However, their therapeutic effects are limited. Therefore, additional research is required to elucidate the mechanisms of PMSC-mediated LIRI prevention and enhance the related therapeutic effects. This study aimed to examine the role of the Lin28 protein in the regulation of glucose metabolism in PMSCs. Further, it explored whether Lin28 could enhance the protective effects of PMSCs against LIRI and investigated the underlying mechanisms. Western blotting was performed to examine Lin28 expression in PMSCs under hypoxic conditions. A Lin28 overexpression construct was introduced into PMSCs, and the effect on glucose metabolism was examined using a glucose metabolism kit. Further, the expression of some proteins involved in glucose metabolism and the PI3K-AKT pathway and the levels of microRNA Let-7a-g were examined using western blots and real-time quantitative PCR, respectively. To examine the relationship between Lin28 and the PI3K-Akt pathway, the effects of AKT inhibitor treatment on the changes induced by Lin28 overexpression were examined. Subsequently, AML12 cells were co-cultured with PMSCs to elucidate the mechanisms via which PMSCs prevent hypoxic injury in liver cells in vitro. Finally, C57BL/6J mice were used to establish a partial warm ischaemia-reperfusion model. The mice received intravenous injections containing PMSCs (control and Lin28-overexpressing PMSCs). Finally, their serum transaminase levels and degree of liver injury were assessed using biochemical and histopathological methods, respectively. Lin28 was upregulated under hypoxic conditions in PMSCs. Lin28 exerted protective effects against hypoxia-induced cell proliferation. Moreover, it increased the glycolytic capacity of PMSCs, allowing PMSCs to produce more energy under hypoxic conditions. Lin28 also activated the PI3K-Akt signalling pathway under hypoxic conditions, and its effects were attenuated by AKT inhibition. Lin28 overexpression could protect cells against LIRI-induced liver damage, inflammation and apoptosis and could also attenuate hypoxia-induced hepatocyte injury. Lin28 enhances glucose metabolism under hypoxic conditions in PMSCs, thereby exerting protective effects against LIRI by activating the PI3K-Akt signalling pathway. Our study is the first to report the potential of genetically modified PMSCs for LIRI treatment.

Hepatic 31 P-magnetic resonance spectroscopy identified the impact of melatonin-pretreated mitochondria in acute liver ischaemia-reperfusion injury

Acute liver ischaemia-reperfusion injury (IRI), commonly encountered during liver resection and transplantation surgery, is strongly associated with unfavourable clinical outcome. However, a prompt and accurate diagnosis and the treatment of this entity remain formidable challenges. This study tested the hypothesis that ³¹ P-magnetic resonance spectroscopy (³¹ P-MRS) findings could provide reliable living images to accurately identify the degree of acute liver IRI and melatonin-pretreated mitochondria was an innovative treatment for protecting the liver from IRI in rat. Adult male SD rats were categorized into group 1 (sham-operated control), group 2 (IRI only) and group 3 (IRI + melatonin [ie mitochondrial donor rat received intraperitoneal administration of melatonin] pretreated mitochondria [10 mg/per rat by portal vein]). By the end of study period at 72 hours, ³¹ P-MRS showed that, as compared with group 1, the hepatic levels of ATP and NADH were significantly lower in group 2 than in groups 1 and 3, and significantly lower in group 3 than in group 1. The liver protein expressions of mitochondrial-electron-transport-chain complexes and mitochondrial integrity exhibited an identical pattern to ³¹ P-MRS finding. The protein expressions of oxidative stress, inflammatory, cellular stress signalling and mitochondrial-damaged biomarkers displayed an opposite finding of ³¹ P-MRS, whereas the protein expressions of antioxidants were significantly progressively increased from groups 1 to 3. Microscopic findings showed that the fibrotic area/liver injury score and inflammatory and DNA-damaged biomarkers exhibited an identical pattern of cellular stress signalling. Melatonin-pretreated mitochondria effectively protected liver against IRI and ³¹ P-MRS was a reliable tool for measuring the mitochondrial/ATP consumption in living animals.

Bucillamine improves hepatic microcirculation and reduces hepatocellular injury after liver warm ischaemia-reperfusion injury

BACKGROUND

Liver transplantation and resection surgery involve a period of ischaemia and reperfusion to the liver which initiates an inflammatory cascade resulting in liver and remote organ injury. Bucillamine is a low-molecular-weight thiol antioxidant that is capable of rapidly entering cells.

METHODS

The effect of bucillamine was studied in a rat model of liver ischaemia-reperfusion injury with 45 min of partial (70%) liver ischaemia and at 3 and 24 h of reperfusion. Controls included ischaemia-reperfusion (I/R) only, sham and bucillamine alone (without ischaemia reperfusion). Liver injury was assessed by serum transaminases (AST and ALT). Sinusoidal blood flow and hepatocyte apoptosis were measured using intravital microscopy (IVM).

RESULTS

The hepatocellular injury of I/R produced a markedly elevated serum AST which was reduced with bucillamine (2072.5 +/- 511.79 vs. 932 +/- 200.8, P < 0.05) at 3 h reperfusion. Bucillamine treatment with I/R also increased parenchymal blood flow [red blood cell (RBC) velocity 242.66 +/- 16.86 vs. 181.11 +/- 17.59, at the end of 3 h of reperfusion) and reduced hepatocyte necrosis/apoptosis at 3 h as well as 24 h (P > 0.001).

CONCLUSION

Bucillamine reduces the hepatocellular injury of liver ischaemia reperfusion and improves parenchymal perfusion.