ABSTRACT
Exposure to the hight-fat diet may alter the control of food intake promoting hyperphagia and obesity. The objective of this study was to investigate the effects of this diet on dopamine receptors (drd1 and drd2), proopiomelanocortin (pomc), neuropeptideY (npy) genes expression, and preference food in adult rats. Wistar female rats were fed a hight-fat or control diet during pregnancy and lactation. The offspring were allocated into groups: Lactation - Control (C) and High-fat (H). Post-weaning Control Control (CC), offspring of mothers C, fed a control diet after weaning; Control Hight-fat (CH), offspring of mothers C, fed a hight-fat diet after weaning; Hight-fat Control (HC), offspring of mothers H, fed with control diet after weaning; and Hight-fat Hight-fat (HH), offspring of mothers H, fed a H diet after weaning. The groups CH and HH presented greater expression of drd1 in comparison to the CC. The drd2 of CH and HC presented higher gene expression than did CC. HH presented higher pomc expression in comparison to the other groups. HC also presented greater expression in comparison to CH. The npy of HH presented greater expression in relation to CH and HC. HH and HC have had a higher preference for a high-fat diet at 102º life's day. The high-fat diet altered the gene expression of the drd1, drd2, pomc and npy, and influencing the food preference for high-fat diet.
A exposição à dieta hiperlipídica pode alterar o controle da ingestão de alimentos, promovendo hiperfagia e obesidade. O objetivo deste estudo foi investigar os efeitos dessa dieta sobre a expressão gênica dos receptores de dopamina (drd1 e drd2), da proopiomelanocortina (pomc) e neuropeptídeo Y (npy), e preferência alimentar em ratos adultos. Ratas Wistar foram alimentadas com uma dieta hiperlipídica ou controle durante a gestação e lactação. Os descendentes foram alocados em grupos: Lactação Controle (C) e Hiperlipídica (H). Pós-desmame - Controle Controle (CC), descendentes das genitoras do grupo controle e alimentados com dieta controle após o desmame; Controle Hiperlipídica (CH), descendentes das genitoras do grupo controle e alimentados com dieta hiperlipídica após o desmame; Hiperlipídica Controle (HC), descendentes das genitoras do grupo hiperlipídica e alimentados com dieta controle após o desmame; Hiperlipídica Hiperlipídica (HH), descendentes das genitoras do grupo hiperlipídica e alimentados com dieta hiperlipídica após o desmame. Os grupos CH e HH apresentaram maior expressão de drd1 em comparação ao CC. O drd2 de CH e HC apresentou maior expressão gênica que o CC. HH apresentou maior expressão de pomc em comparação com os outros grupos. O HC também apresentou maior expressão de pomc em comparação ao CH. O npy do HH apresentou maior expressão em relação ao CH e HC. HH e HC tiveram uma preferência maior por uma dieta rica em gordura no 102º dia de vida. A dieta hiperlipídica alterou a expressão gênica dos drd1, drd2, pomc e npy e influenciou na preferência alimentar pela dieta hiperlipídica.
Subject(s)
Animals , Female , Pregnancy , Rats , Pro-Opiomelanocortin/genetics , Diet, High-Fat/adverse effects , Body Weight , Neuropeptide Y/genetics , Gene Expression , Receptors, Dopamine/genetics , Rats, Wistar , Food PreferencesABSTRACT
Promoter CpG island hypermethylation has become recognized as an important mechanism for inactivating tumor suppressor genes or tumor-related genes in human cancers of various tissues. Gene inactivation in association with promoter CpG island hypermethylation has been reported to be four times more frequent than genetic changes in human colorectal cancers. Hepatocellular carcinoma is also one of the human cancer types in which aberrant promoter CpG island hypermethylation is frequently found. However, the number of genes identified to date as hypermethylated for hepatocellular carcinoma (HCC) is fewer than that for colorectal cancer or gastric cancer, which can be attributed to fewer attempts to perform genome-wide methylation profiling for HCC. In the present study, we used bead-array technology and coupled methylation-specific PCR to identify new genes showing cancer-specific methylation in HCC. Twenty-four new genes have been identified as hypermethylated at their promoter CpG island loci in a cancer-specific manner. Of these, TNFRSF10C, HOXA9, NPY, and IRF5 were frequently hypermethylated in hepatocellular carcinoma tissue samples and their methylation was found to be closely associated with inactivation of gene expression. Further study will be required to elucidate the clinicopathological implications of these newly found DNA methylation markers in hepatocellular carcinoma.
Subject(s)
Humans , Antimetabolites, Antineoplastic/therapeutic use , Azacitidine/analogs & derivatives , Carcinoma, Hepatocellular/drug therapy , Cell Line, Tumor , CpG Islands , DNA Methylation , GPI-Linked Proteins/genetics , Gene Expression Profiling , Homeodomain Proteins/genetics , Interferon Regulatory Factors/genetics , Liver Neoplasms/drug therapy , Neuropeptide Y/genetics , Oligonucleotide Array Sequence Analysis , Promoter Regions, Genetic , Tumor Necrosis Factor Decoy Receptors/geneticsABSTRACT
O tabagismo é a principal causa de morte prevenível na maioria dos países, inclusive no Brasil. Parar de fumar é uma estratégia importante para reduzir a morbidade e mortalidade associada às doenças tabaco-relacionadas. Sabe-se da relação inversa entre uso de nicotina e peso corporal, onde o índice de massa corporal tende a ser menor em fumantes quando comparados aos não fumantes. Além disso, abstinência tabágica resulta em aumento de peso, sendo que ex-fumantes geralmente aumentam de 5 a 6 kg, mas cerca de 10 por cento adquirem mais de 10 kg. O tratamento farmacológico para a cessação do tabagismo pode atenuar este ganho de peso. O aumento de peso na cessação do tabagismo como contributório à epidemia de obesidade é pouco estudado. Nos EUA, calcula-se que a fração do problema atribuível à cessação do tabagismo seja de 6 por cento para homens e 3,2 por cento para mulheres. Os mecanismos não são claros, mas há evidências mostrando que a dopamina e serotonina diminuem a ingestão alimentar. A administração de nicotina por qualquer via eleva agudamente os níveis destes neurotransmissores no cérebro, causando menor necessidade de ingestão energética e diminuindo o apetite. Além disso, a nicotina tem efeito direto no metabolismo do tecido adiposo, influenciando a taxa de ganho ponderal após a cessação do tabagismo. A leptina, grelina e neuropeptídio Y são peptídeos que podem contribuir para esta relação inversa entre nicotina e índice de massa corporal, em um papel ainda não determinado como conseqüente ou causador das variações ponderais.
Tobacco use is the leading preventable cause of death in most countries, including Brazil. Smoking cessation is an important strategy for reducing the morbidity and mortality associated with tobacco-related diseases. An inverse relationship between nicotine use and body weight has been reported, in which body weight tends to be lower among smokers than among nonsmokers. Smoking abstinence results in an increase in body weight for both males and females. On average, sustained quitters gain from 5 to 6 kg, although approximately 10 percent gain more than 10 kg. Pharmacological treatment for smoking cessation attenuates weight gain. The importance of smoking cessation as a contributing cause of the current obesity epidemic has been little studied. In the USA, the rate of obesity attributable to smoking cessation has been estimated at approximately 6.0 and 3.2 percent for males and females, respectively. Although the mechanisms are unclear, there is evidence that dopamine and serotonin are appetite suppressants. The administration of nicotine, regardless of the delivery system, acutely raises the levels of these neurotransmitters in the brain, reducing the need for energy intake and consequently suppressing appetite. In addition, nicotine has a direct effect on adipose tissue metabolism, influencing the rate of weight gain following smoking cessation. Leptin, ghrelin and neuropeptide Y are substances that might constitute factors involved in the inverse relationship between nicotine and body mass index, although their roles as determinants or consequences of this relationship have yet to be determined.