Fengming Xu

Background: Excessive intake of fatty acids is a key factor contributing to metabolic dysfunction-associated steatotic liver disease (MASLD). However, the effects of saturated fatty acids (SFA) and unsaturated fatty acids (UFA) on the development of MASLD are uncertain. Therefore, we conducted two-sample Mendelian randomization studies and animal experiments to explore the effects of SFA, monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) on the risk of developing MASLD. Methods: The genetic summary data of exposures and outcome were retrieved from genome-wide association studies (GWASs) and used for five Mendelian randomization methods. A comprehensive sensitivity analysis was performed to verify the robustness of the results. Mice were subjected to different diets followed by assessment of severity of steatosis based on a histological score and determination of hepatic triglyceride levels to investigate the relationships between SFA, MUFA, PUFA and MASLD. Results: The Mendelian randomization results showed that MUFA (odds ratio: 1.441, 95% confidence interval: 1.078–1.927, P = 0.014) was causally associated with the incidence of MASLD. SFA and PUFA were not causally associated with the incidence of MASLD. Sensitivity analysis did not identify any significant bias in the results. The animal experiment results showed that a MUFA-enriched diet significantly contributed to the development of hepatic steatosis (P < 0.001). Conclusion: SFA and PUFA did not have a significant causal effect on MASLD, but MUFA intake is a risk factor for MASLD. A MUFA-enriched diet increased the incidence of macrovesicular steatosis and the hepatic triglyceride levels. Therefore, replacing MUFA intake with a moderate intake of PUFA might help reduce the risk of MASLD. Graphical

Purpose: The autophagy inhibitor chloroquine enhances the effect of targeted therapy using tyrosine kinase inhibitor in liver cancer. We would like to further understand the specific mechanism by which chloroquine inhibits the proliferation of tumor cells. Methods: We used a human hepatocarcinoma cell line (HepG2) as cell culture model. In contrast to the control groups (treated only with complete medium), cells in experimental groups were treated either with complete medium + 40 ng/ml Hepatocyte growth factor (HGF), or with complete medium + 60 μM chloroquine or with complete medium + 40 ng/ml HGF + 60 μM chloroquine for 24 h. Cell number and ATP content were investigated using spectrophotometric assays. Cell proliferation and apoptosis were detected by immunohistochemistry. Cell morphological alterations were examined by Giemsa and H&E staining. Cellular lipid content was determined by Oil Red O staining and Triglyceride quantification assay. Autophagy-related proteins (LC3B and p62) and hepatocyte proliferation-related protein (S6K1) were examined using western blot. The autophagic flux of cells was assessed by mRFP-EGFP-LC3 transfection assay. Results: We found that chloroquine inhibited the proliferation of HepG2 cells, as evidenced by a decrease in cellular ATP content, Ki-67 and S6K1 protein expression and a reduction in cell number. This finding was associated with an increase in lipid content. As expected, chloroquine inhibited autophagy of HepG2 cells, as evidenced by the accumulation of LC3B-II and the significant upregulation of p62. mRFP-EGFP-LC3 transfection assay showed that indeed chloroquine blocked the autophagic flux in HepG2 cells. Conclusion: Chloroquine impaired proliferation of HepG2 cells might be due to intracellular accumulation of lipids and inhibition of energy synthesis.

Aging is a natural life process which leads to a gradual decline of essential physiological processes. For the liver, it leads to alterations in histomorphology (steatosis and fibrosis) and function (protein synthesis and energy generation) and affects central hepatocellular processes (autophagy, mitochondrial respiration, and hepatocyte proliferation). These alterations do not only impair the metabolic capacity of the liver but also represent important factors in the pathogenesis of malignant liver disease. Autophagy is a recycling process for eukaryotic cells to degrade dysfunctional intracellular components and to reuse the basic substances. It plays a crucial role in maintaining cell homeostasis and in resisting environmental stress. Emerging evidence shows that modulating autophagy seems to be effective in improving the age‐related alterations of the liver. However, autophagy is a double‐edged sword for the aged liver. Upregulating autophagy alleviates hepatic steatosis and ROS‐induced cellular stress and promotes hepatocyte proliferation but may aggravate hepatic fibrosis. Therefore, a well‐balanced autophagy modulation strategy might be suitable to alleviate age‐related liver dysfunction. Conclusion. Modulation of autophagy is a promising strategy for “rejuvenation” of the aged liver. Detailed knowledge regarding the most devastating processes in the individual patient is needed to effectively counteract aging of the liver without causing obvious harm.

In-vivo liver decellularization has become a promising strategy to study in-vivo liver engineering. However, long term survival after in-vivo liver decellularization has not yet been achieved due to anatomical and technical challenges. This study aimed to establish a survival model of in-vivo partial liver lobe perfusion-decellularization in rat. We compared three decellularization protocols (1%Triton X100 followed by 1%SDS, 1%SDS versus 1%Triton X100, n=6/group). Using the optimal one as judged by macroscopy, histology and DNA-content, we characterized the structural integrity and matrix-proteins using histology, scanning electron microscopy (SEM), Computed Tomography (CT) scanning and immunohistochemistry. We prevented contamination of the abdominal cavity with the corrosive detergents by using polyvinylidene chloride (PVDC) film + dry gauze in comparison to PVDC-film + dry gauze + aspiration tube (n=6/group). Physiological reperfusion was assessed by histology. Survival rate was determined after a 7 d observation period. Only perfusion with 1% SDS resulted in an acellular scaffold (fully translucent without histologically detectable tissue remnants, DNA concentration is less than 2% of that in native lobe) with remarkable structural and ultrastructural integrity as well as preservation of main matrix proteins (immunohistochemically positive for collagen IV, laminin, and elastin). Contamination of abdominal organs with the potentially toxic SDS-solution was achieved by placing a suction tube in addition to the PDVC-film + dry gauze and allowed 7d-survival of all animals without severe postoperative complications. Upon reperfusion, the liver turned red within sec without any leakage from the surface of the liver. About 12 h after reperfusion, blood cells but also some clots were visible in the portal vein (PV), sinusoidal matrix network and central vein (CV), suggesting physiological perfusion. In conclusion, our results study shows the first available data on generation of a survival model of in-vivo parenchymal organ decellularization, creating a critical step towards in-vivo organ engineering.