Associations of nicotinamide N-methyltransferase gene single nucleotide polymorphisms with sport performance and relative maximal oxygen uptake.

To observe the associations between single nucleotide polymorphisms (SNPs) of nicotinamide N-methyltransferase (NNMT) gene and sport performance and to analyse genotype associations of the associated SNPs with sport performance and relative maximal oxygen uptake ([Formula: see text]). Participants were selected from 685 Chinese Han male college students. The completion times of a 1000-m run and a 50-m run were used to reflect sport performance, respectively. Nineteen tagSNPs were genotyped with Polymerase chain reaction-ligase detection reaction. Relative [Formula: see text] was directly determined with a cardiopulmonary function analyser. A significant association was found between rs2256292 and 1000-m run performance, but no significant association was found between any tagSNPs and 50-m run performance. The genotype associations of rs2256292 with 1000-m run performance and with relative [Formula: see text] were both significant under the recessive model (CC vs. CG + GG). No tagSNP in NNMT is significantly associated with 50-m run performance but rs2256292 is significantly associated with 1000-m run performance. The genotype associations of rs2256292 with sport performance are significant under recessive model, and a higher relative [Formula: see text] may be the physiological reason for minor homozygote CC carriers being of the better 1000-m runners.

Physiological Study on Association between Nicotinamide N-Methyltransferase Gene Polymorphisms and Hyperlipidemia.

Nicotinamide N-methyltransferase (NNMT) catalyzes the methylation of nicotinamide. Our previous works indicate that NNMT is involved in the body mass index and energy metabolism, and recently the association between a SNP (rs694539) of NNMT and a variety of cardiovascular diseases was reported. At present, more than 200 NNMT single nucleotide polymorphisms (SNPs) have been identified in the databases of the human genome projects; however, the association between rs694539 variation and hyperlipidemia has not been reported yet, and whether there are any SNPs in NNMT significantly associated with hyperlipidemia is still unclear. In this paper, we selected 19 SNPs in NNMT as the tagSNPs using Haploview software (Haploview 4.2) first and then performed a case-control study to observe the association between these tagSNPs and hyperlipidemia and finally applied physiological approaches to explore the possible mechanisms through which the NNMT polymorphism induces hyperlipidemia. The results show that a SNP (rs1941404) in NNMT is significantly associated with hyperlipidemia, and the influence of rs1941404 variation on the resting energy expenditure may be the possible mechanism for rs1941404 variation to induce hyperlipidemia.

[Expression of Aquaporin 4 in Diffuse Brain Injury of Rats].

OBJECTIVE: To observe the expression of aquaporin 4 (AQP4) in diffuse brain injury (DBI) of rats and to explore the corresponding effect of AQP4 for brain edema. METHODS: The rat model of DBI was established using Marmarou's impact-compression trauma model. Brain water content was measured by dry-wet weight method. Blood-brain barrier permeability was evaluated by Evans blue (EB) staining. Immunohistochemical method was used to observe the expression of AQP4. RESULTS: Brain water content increased after 3 h and peaked at 24 h after DBI. Brain EB content significantly increased and peaked at 12 h after DBI. The expression of AQP4 significantly increased after 3 h and peaked at 24 h after DBI, and the number of AQP4 positive astrocytes increased. CONCLUSION: The increment of the permeability of blood-brain barrier and the expression of AQP4 may contribute to the development of brain edema in rat DBI. The change of AQP4 expression in astrocytes may also contribute to determine DBI.

Health effects from swimming training in chlorinated pools and the corresponding metabolic stress pathways.

Chlorination is the most popular method for disinfecting swimming pool water; however, although pathogens are being killed, many toxic compounds, called disinfection by-products (DBPs), are formed. Numerous epidemiological publications have associated the chlorination of pools with dysfunctions of the respiratory system and with some other diseases. However, the findings concerning these associations are not always consistent and have not been confirmed by toxicological studies. Therefore, the health effects from swimming in chlorinated pools and the corresponding stress reactions in organisms are unclear. In this study, we show that although the growth and behaviors of experimental rats were not affected, their health, training effects and metabolic profiles were significantly affected by a 12-week swimming training program in chlorinated water identical to that of public pools. Interestingly, the eyes and skin are the organs that are more directly affected than the lungs by the irritants in chlorinated water; instead of chlorination, training intensity, training frequency and choking on water may be the primary factors for lung damage induced by swimming. Among the five major organs (the heart, liver, spleen, lungs and kidneys), the liver is the most likely target of DBPs. Through metabolomics analysis, the corresponding metabolic stress pathways and a defensive system focusing on taurine were presented, based on which the corresponding countermeasures can be developed for swimming athletes and for others who spend a lot of time in chlorinated swimming pools.