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Background and aims: Cerium oxide nanoparticles are effective scavengers of reactive oxygen species and have been proposed as a treatment for oxidative stress-related diseases. Consequently, we aimed to investigate the effect of these nanoparticles on hepatic regeneration after liver injury by partial hepatectomy and acetaminophen overdose. Methods: All the in vitro experiments were performed in HepG2 cells. For the acetaminophen and partial hepatectomy experimental models, male Wistar rats were divided into three groups: (1) nanoparticles group, which received 0.1 mg/kg cerium nanoparticles i.v. twice a week for 2 weeks before 1 g/kg acetaminophen treatment, (2) N-acetyl-cysteine group, which received 300 mg/kg of N-acetyl-cysteine i.p. 1 h after APAP treatment and (3) partial hepatectomy group, which received the same nanoparticles treatment before partial hepatectomy. Each group was matched with vehicle-controlled rats. Results: In the partial hepatectomy model, rats treated with cerium oxide nanoparticles showed a significant increase in liver regeneration, compared with control rats. In the acetaminophen experimental model, nanoparticles and N-acetyl-cysteine treatments decreased early liver damage in hepatic tissue. However, only the effect of cerium oxide nanoparticles was associated with a significant increment in hepatocellular proliferation. This treatment also reduced stress markers and increased cell cycle progression in hepatocytes and the activation of the transcription factor NF-κB in vitro and in vivo. Conclusions: Our results demonstrate that the nanomaterial cerium oxide, besides their known antioxidant capacities, can enhance hepatocellular proliferation in experimental models of liver regeneration and drug-induced hepatotoxicity. [ABSTRACT FROM AUTHOR]

Background and aims: The occurrence of endothelial alterations in the liver and in the splanchnic vasculature of cirrhotic patients and experimental models of liver diseases has been demonstrated. However, the pathological role of the portal vein endothelium in this clinical context is scarcely studied and, therefore, deserves attention. In this context, we aimed to investigate whether pathological endothelial activation occurs in the portal vein of cirrhotic rats. Methods: Cirrhosis was induced in wistar rats by CCl4 inhalation. We generated immortalized endothelial cells from the portal vein of control (CT-iPVEC) and cirrhotic rats (CH-iPVEC) by retroviral transduction of the SV40 T antigen. We assessed differential gene expression and intracellular reactive oxygen species (ROS) levels in iPVECs and in portal veins of control and cirrhotic rats. Finally, we assessed the therapeutic effectiveness of cerium oxide nanoparticles (CeO2NP) on reversing PVEC activation and macrophage polarization. Results: CH-iPVECs overexpressed collagen-I, endothelin-1, TIMP-1, TIMP-2, IL-6 and PlGF genes. These results were consistent with the differential expression showed by whole portal veins from cirrhotic rats. In addition, CH-iPVECs showed a significant increase in intracellular ROS and the capacity of potentiating M1 polarization in macrophages. The treatment of CH-iPVECs with CeO2NPs blocked intracellular ROS formation and IL-6 and TIMP-2 gene overexpression. In agreement with the in vitro results, the chronic treatment of cirrhotic rats with CeO2NPs also resulted in the blockade of both ROS formation and IL-6 gene overexpression in whole portal veins. Conclusions: Endothelial cells from portal vein of cirrhotic rats depicted an abnormal phenotype characterized by a differential gene expression and the induction of M1 polarization in macrophages. We identified the excess of intracellular reactive oxygen species (ROS) as a major contributor to this altered phenotype. In addition, we demonstrated the utility of the nanomaterial cerium oxide as an effective antioxidant capable of reverse some of these pathological features associated with the portal vein in the cirrhosis condition. [ABSTRACT FROM AUTHOR]

Cerium oxide nanoparticles (CeO2NPs) possess powerful antioxidant properties, thus emerging as a potential therapeutic tool in non-alcoholic fatty liver disease (NAFLD) progression, which is characterized by a high presence of reactive oxygen species (ROS). The aim of this study was to elucidate whether CeO2NPs can prevent or attenuate oxidant injury in the hepatic human cell line HepG2 and to investigate the mechanisms involved in this phenomenon. The effect of CeO2NPs on cell viability and ROS scavenging was determined, the differential expression of pro-inflammatory and oxidative stress-related genes was analyzed, and a proteomic analysis was performed to assess the impact of CeO2NPs on cell phosphorylation in human hepatic cells under oxidative stress conditions. CeO2NPs did not modify HepG2 cell viability in basal conditions but reduced H2O2- and lipopolysaccharide (LPS)-induced cell death and prevented H2O2-induced overexpression of MPO, PTGS1 and iNOS. Phosphoproteomic analysis showed that CeO2NPs reverted the H2O2-mediated increase in the phosphorylation of peptides related to cellular proliferation, stress response, and gene transcription regulation, and interfered with H2O2 effects on mTOR, MAPK/ERK, CK2A1 and PKACA signaling pathways. In conclusion, CeO2NPs protect HepG2 cells from cell-induced oxidative damage, reducing ROS generation and inflammatory gene expression as well as regulation of kinase-driven cell survival pathways. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, ranging from steatosis to non-alcoholic steatohepatitis (NASH). Recently, cerium oxide nanoparticles (CeO2NPs) have emerged as a new antioxidant agent with hepatoprotective properties in experimental liver disease. The aim of the current investigation was to elucidate whether CeO2NPs display beneficial effects in an experimental model of NAFLD.Therefore, fifteen Wistar rats were subjected to a methionine and choline deficient diet (MCDD) for 6 weeks and intravenously treated with CeO2NP or vehicle during the weeks three and four of the diet. The effect of CeO2NPs on serum biochemistry, hepatic steatosis, inflammation, fatty acid content and expression of reactive oxygen species (ROS) and lipid metabolism related genes was assessed. MCDD fed rats showed increased inflammation, enhanced hepatic lipid accumulation of both saturated and unsaturated fatty acids (FAs) and overexpression of genes related to fatty liver and ROS metabolism. Treatment with CeO2NPs was able to reduce the size and content of hepatocyte lipid droplets, the hepatic concentration of triglyceride- and cholesterol ester-derived FAs and the expression of several genes involved in cytokine, adipokine and chemokine signaling pathways. These findings suggest that CeO2NPs could be of beneficial value in NAFLD. [ABSTRACT FROM AUTHOR]