Genetic polymorphisms in XRCC1 genes and colorectal cancer susceptibility.

BACKGROUND: The objective of this study is to investigate the association among the polymorphisms of XRCC1 gene, smoking, drinking, family history of tumors, and the risk of colorectal cancer (CRC) in the population of Han nationality in Jiangsu Province, China. METHODS: A case-control study of 320 patients with CRC and 350 cancer-free subjects as a control group was conducted. The three polymorphic sites, codons 194, 280, and 399, of XRCC1 genes were analyzed by PCR-RFLP. RESULTS: We find that heavy smoking (>500 cigarettes per year) significantly increased the susceptibility of CRC (OR=1.89, 95% confidence interval (CI) 1.27-2.84) after stratification by total smoking amount. There was also significant difference between cases and controls when family history of tumors (OR=2.96, 95% CI 1.76-4.99) was considered. Comparing with individuals carrying XRCC1 399Arg/Arg genotype, the subjects with 399Arg/Gln (OR=1.46, 95% CI 1.06-2.01) or 399Gln/Gln genotype (OR=1.93, 95% CI 1.05-3.54) had a significantly increased risk for CRC. Taking smoking and drinking habits into consideration, we found that subjects with heavy smoking history and XRCC1 194Arg allele had the significantly increased risk for CRC (OR=2.91, 95% CI 1.35-6.24). Individuals, who carry 399Gln allele and have a heavy smoking (OR=2.72, 95% CI 1.52-4.89) or drinking habit (OR=1.98, 95% CI 1.06-3.67), also have higher risk. In smoking population, 194Arg (P=0.491) and 399Gln (P=0.912) had not significantly increased risk for CRC, so did 399Gln (P=0.812) in smoking population. CONCLUSIONS: Individuals carrying XRCC1 399Gln allele with a smoking or drinking habit were in increased risk, and heavy-smoking subjects with 194Arg allele also have higher risk for CRC in the Han nationality population of Jiangsu Province, which also showed a positive correlation with exposure dose of tobacco. But XRCC1 399Gln allele or 194Arg allele were not independent risk factors for CRC in smoking or drinking population.

Modulation of fatty acid metabolism is involved in the alleviation of isoproterenol-induced rat heart failure by fenofibrate.

Heart failure is a disease predominantly caused by an energy metabolic disorder in cardiomyocytes. The present study investigated the inhibitory effects of fenofibrate (FF) on isoproterenol (ISO)­induced hear failure in rats, and examined the underlying mechanisms. The rats were divided into CON, ISO (HF model), FF and FF+ISO (HF animals pretreated with FF) groups. The cardiac structure and function of the rats were assessed, and contents of free fatty acids and glucose metabolic products were determined. In addition, myocardial cells were isolated from neonatal rats and used in vitro to investigate the mechanisms by which FF relieves heart failure. Western blot analysis was performed to quantify the expression levels of peroxisome proliferator­activated receptor (PPAR)α and uncoupling protein 2 (UCP2). FF effectively alleviated the ISO­induced cardiac structural damage, functional decline, and fatty acid and carbohydrate metabolic abnormalities. Compared with the ISO group, the serum levels of brain natriuretic peptide (BNP), free fatty acids, lactic acid and pyruvic acid were decreased in the FF animals. In the cultured myocardial cells, lactic acid and pyruvic acid contents were lower in the supernatants obtained from the FF animals, with lower levels of mitochondrial ROS production and cell necrosis, compared with the ISO group, whereas PPARα upregulation and UCP2 downregulation occurred in the FF+ISO group. The results demonstrated that FF efficiently alleviated heart failure in the ISO­induced rat model, possibly via promoting fatty acid oxidation.