Impact of hyperuricaemia on the chronic kidney disease-associated risk factors in a community-based population.

AIM: Hyperuricaemia is a common finding in subjects with lifestyle related diseases. This study was performed to examine its association with chronic kidney disease (CKD) in relation to other risk factors in a community-based population. METHODS: Data from 187 914 participants, excepting CKD stage 5, of the health check-up were included in this analysis. The association between CKD and its risk factors were examined by a logistic analysis. The association of hyperuricaemia and CKD was also compared in the population without any lifestyle related diseases and the whole population. RESULTS: The prevalence of hyperuricaemia was significantly higher in the advanced stage of CKD. The odds ratio of hyperuricaemia was higher than that of other factors for the association with CKD. The odds ratio of many CKD-associated variables was increased in the advanced stage. Among them, the odds ratio of hyperuricaemia was markedly increased. The prevalence of hyperuricaemia was lower in the population without any lifestyle related diseases than in the whole population in the early stages, the difference of prevalence between the two populations becoming smaller in the advanced stage. CONCLUSIONS: The association of incident CKD with hyperuricaemia was stronger than with other chronic kidney disease-risk factors, this association becoming more significant in the advanced stage of chronic kidney disease. Although this result does not indicate the cause and result relationship, the data suggest that hyperuricaemia might not be appropriately treated in this population.

Molecular cloning, expression, and signaling pathway of four melanin-concentrating hormone receptors from Xenopus tropicalis.

Melanin-concentrating hormone (MCH) mainly regulates feeding in mammals and pigmentation in teleosts. It acts via two G-protein-coupled receptors, MCH receptor 1 (MCHR1) and MCHR2. Although many studies exploring the MCH system in teleosts and mammals have been carried out, studies on other organisms are limited. In this study, we cloned and characterized four MCHR subtypes from the diploid species Xenopus tropicalis (X-MCHRs; X-MCHR1a, R1b, R2a, and R2b). According to a phylogenetic tree of the X-MCHRs, X-MCHR1a and R2a are close to mammalian MCHRs, while X-MCHR1b and R2b are close to teleostean MCHRs. We previously reported that the G-protein coupling capacity of the MCHR subtypes differed between mammals (R1: Gαi/o and Gαq; R2: Gαq) and teleosts (R1: Gαq; R2: Gαi/o and Gαq) in mammalian cell-based assays. By using Ca(2+) mobilization assays with pertussis toxin in CHO dhfr(-) cells, we found that X-MCHR1a promiscuously coupled to both Gαi/o and Gαq, while X-MCHR1b and R2a exclusively coupled to Gαq. However, no Ca(2+) influx was detected in cells transfected with X-MCHR2b. Reverse transcription-PCR showed that the X-MCHR mRNAs were expressed in various tissues. In particular, both X-MCHR1b and R2b were exclusively found in melanophores of the dorsal skin. In skin pigment migration assays, melanophores were weakly aggregated at low concentrations but dispersed at high concentrations of MCH, suggesting possible interactions between X-MCHR1b and R2b for the regulation of body color. These findings demonstrate that X. tropicalis has four characteristic MCHRs and will be useful for elucidating the nature of MCHR evolution among vertebrates.