Research Article Details

Article ID: A26753
PMID: 19832698
Source: Clin Sci (Lond)
Title: Hypoxia aggravates non-alcoholic steatohepatitis in mice lacking hepatocellular PTEN.
Abstract: The metabolic disorders that predispose patients to NASH (non-alcoholic steatohepatitis) include insulin resistance and obesity. Repeated hypoxic events, such as occur in obstructive sleep apnoea syndrome, have been designated as a risk factor in the progression of liver disease in such patients, but the mechanism is unclear, in particular the role of hypoxia. Therefore we studied the influence of hypoxia on the development and progression of steatohepatitis in an experimental mouse model. Mice with a hepatocellular-specific deficiency in the Pten (phosphatase and tensin homologue deleted on chromosome 10) gene, a tumour suppressor, were exposed to a 10% O2 (hypoxic) or 21% O2 (control) atmosphere for 7 days. Haematocrit, AST (aspartate aminotransferase), glucose, triacylglycerols (triglycerides) and insulin tolerance were measured in blood. Histological lesions were quantified. Expression of genes involved in lipogenesis and mitochondrial beta-oxidation, as well as FOXO1 (forkhead box O1), hepcidin and CYP2E1 (cytochrome P450 2E1), were analysed by quantitative PCR. In the animals exposed to hypoxia, the haematocrit increased (60+/-3% compared with 50+/-2% in controls; P<0.01) and the ratio of liver weight/body weight increased (5.4+/-0.2% compared with 4.7+/-0.3% in the controls; P<0.01). Furthermore, in animals exposed to hypoxia, steatosis was more pronounced (P<0.01), and the NAS [NAFLD (non-alcoholic fatty liver disease) activity score] (8.3+/-2.4 compared with 2.3+/-10.7 in controls; P<0.01), serum AST, triacylglycerols and glucose were higher. Insulin sensitivity decreased in mice exposed to hypoxia relative to controls. The expression of the lipogenic genes SREBP-1c (sterol-regulatory-element-binding protein-1c), PPAR-gamma (peroxisome-proliferator-activated receptor-gamma), ACC1 (acetyl-CoA carboxylase 1) and ACC2 (acetyl-CoA carboxylase 2) increased significantly in mice exposed to hypoxia, whereas mitochondria beta-oxidation genes [PPAR-alpha (peroxisome-proliferator-activated receptor-alpha) and CPT-1 (carnitine palmitoyltransferase-1)] decreased significantly. In conclusion, the findings of the present study demonstrate that hypoxia alone aggravates and accelerates the progression of NASH by up-regulating the expression of lipogenic genes, by down-regulating genes involved in lipid metabolism and by decreasing insulin sensitivity.
DOI: 10.1042/CS20090313

Strategy ID Therapy Strategy Synonyms Therapy Targets Therapy Drugs
S01 Improve insulin resistance insulin sensitizer; insulin resistance; glucose tolerance Biguanide: increases 5-AMP activated protein kinase signaling; SGLT-2 inhibitor; Thiazalidinedione: selective PPAR-γ agonists; GLP-1 agonist Metformin; Empagliflozin; Canagliflozin; Rosiglitazone; Pioglitazone; Liraglutide Details
S02 Enhance lipid metabolism triglyceride-lowering; lipid tolerance; lipid metabolism 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) inhibitor; Decreases intestinal cholesterol absorption; FXR agonist; ACC inhibitor; FAS inhibitor; DGAT2 inhibitor; SCD-1 inhibitor Atorvastatin; Ezetimibe; Obeticholic Acid; GS-9674; GS-0976; TVB-2640; IONIS-DGAT2rx; Aramchol; Details

Target ID Target Name GENE Action Class UniProtKB ID Entry Name
T18 Acetyl-CoA carboxylase 1 ACACA inhibitor Enzyme Q13085 ACACA_HUMAN Details
T19 Acetyl-CoA carboxylase 2 ACACB inhibitor Enzyme O00763 ACACB_HUMAN Details
T10 Caspase-1 CASP1 inhibitor Enzyme P29466 CASP1_HUMAN Details
T03 Peroxisome proliferator-activated receptor alpha PPARA agonist Nuclear hormone receptor Q07869 PPARA_HUMAN Details

Diseases ID DO ID Disease Name Definition Class
I05 9352 Type 2 diabetes mellitus A diabetes that is characterized by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both. A diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. http://en.wikipedia.org/wiki/Diabetes, http://en.wikipedia.org/wiki/Diabetes_mellitus_type_2 disease of metabolism/inherited metabolic disorder/ carbohydrate metabolic disorder/glucose metabolism disease/diabetes/ diabetes mellitus Details
I14 9970 Obesity An overnutrition that is characterized by excess body fat, traditionally defined as an elevated ratio of weight to height (specifically 30 kilograms per meter squared), has_material_basis_in a multifactorial etiology related to excess nutrition intake, decreased caloric utilization, and genetic susceptibility, and possibly medications and certain disorders of metabolism, endocrine function, and mental illness. https://en.wikipedia.org/wiki/Obesity disease of metabolism/acquired metabolic disease/ nutrition disease/overnutrition Details

Drug ID Drug Name Type DrugBank ID Targets Category Latest Progress
D579 Emfilermin Miscellany -- adipocytes Enhance lipid metabolism Under investigation Details
D328 Serine Chemical drug DB00133 SRR Improve insulin resistance Under clinical trials Details
D201 L-Carnitine Supplement DB00583 SLC22A4; SLC22A5; CRAT; MPO -- Under clinical trials Details
D182 Insulin Biological drug DB00030 INSR agonist; CPE modulator&product of -- Under clinical trials Details
D062 Carnitine complex Supplement DB00583 SLC22A4; SLC22A5; CRAT; MPO -- Under clinical trials Details
D253 Oleoylethanolamide Chemical drug DB16495 -- -- Under clinical trials Details
D094 Cysteamine Chemical drug DB00847 GSS stimulant Renal drug Under clinical trials Details
D095 Cysteamine bitartrate Chemical drug DB00847 -- -- Under clinical trials Details