title: Cardiovascular disease is associated with high-fat-diet-induced liver damage and up-regulation of the hepatic expression of hypoxia-inducible factor 1α in a rat model.
abstract: CVD (cardiovascular disease) is associated with abnormal liver enzymes, and NAFLD (non-alcoholic fatty liver disease) is independently associated with cardiovascular risk. To gain insights into the molecular events underlying the association between liver enzymes and CVD, we developed an HFD (high-fat diet)-induced NAFLD in the SHR (spontaneously hypertensive rat) and its control WKY (Wistar-Kyoto) rat strain. We hypothesized that hepatic induction of Hif1a (hypoxia-inducible factor 1α) might be the link between CVD and liver injury. Male SHRs (n=13) and WKY rats (n=14) at 16 weeks of age were divided into two experimental groups: standard chow diet and HFD (10 weeks). HFD-fed rats, irrespective of the strain, developed NAFLD; however, only HFD-SHRs had focus of lobular inflammation and high levels of hepatic TNFα (tumour necrosis factor α). SHRs had significantly higher liver weight and ALT (alanine aminotransferase) levels, irrespective of NAFLD. Liver abundance of Hif1a mRNA and Hif1α protein were overexpressed in SHRs (P<0.04) and were significantly correlated with ALT levels (R=0.50, P<0.006). This effect was not reverted by a direct acting splanchnic vasodilator (hydralazine). Angiogenesis may be induced by the HFD, but the disease model showed significantly higher hepatic Vegf (vascular endothelial growth factor) levels (P<0.025) even in absence of dietary insult. Hif1a mRNA overexpression was not observed in other tissues. Liver mRNA of Nr1d1 (nuclear receptor subfamily 1, group D, member 1; P<0.04), Ppara [Ppar (peroxisome-proliferator-activated receptor) α; P<0.05], Pparg (Pparγ; P<0.001) and Sirt1 (Sirtuin 1; P<0.001) were significantly upregulated in SHRs, irrespective of NAFLD. Sirt1 and Hif1a mRNAs were significantly correlated (R=0.71, P<0.00002). In conclusion, CVD is associated with Hif1a-related liver damage, hepatomegaly and reprogramming of liver metabolism, probably to compensate metabolic demands.
authors: Department of Molecular Genetics and Biology of Complex Diseases, Institute of Medical Research A Lanari-IDIM, University of Buenos Aires-National Council of Scientific and Technological Research, Ciudad Autónoma de Buenos Aires, Argentina.
authors: Adriana L
authors: AL
authors: Burgueño
authors: Tomas F
authors: TF
authors: Gianotti
authors: Noelia G
authors: NG
authors: Mansilla
authors: Carlos J
authors: CJ
authors: Pirola
authors: Silvia
authors: S
authors: Sookoian
mesh_terms: D000410:Alanine Transaminase / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002318:Cardiovascular Diseases / Q000150:complications / Q000201:enzymology / Q000209:etiology*; D059305:Diet, High-Fat / Q000009:adverse effects*; D005234:Fatty Liver / Q000150:complications / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D005947:Glucose / Q000378:metabolism; D006652:Histological Techniques; D006830:Hydralazine; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D065626:Non-alcoholic Fatty Liver Disease; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D060888:Real-Time Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D006830:Hydralazine; D000410:Alanine Transaminase; D005947:Glucose