Impact of single nucleotide polymorphism on short stature and reduced tongue pressure among community-dwelling elderly Japanese participants: a cross-sectional study

Background: Asian-specific single nucleotide polymorphism (SNPs) (rs3782886) is reported to be associated with myocardial infarction; sarcopenia is reported to be associated with coronary subclinical atherosclerosis. On the other hand, short stature has been revealed as an independent risk factor for cardiovascular disease. However, no studies have reported on the association between sarcopenia and short stature nor on the impact of rs3782886 on this association. Methods: Since reduced maximum voluntary tongue pressure against the palate (MTP) reflects one aspect of sarcopenia, we conducted a cross-sectional study of 537 community-dwelling elderly Japanese participants aged 60?89 years who had participated in a general health checkup in 2015. Short stature was defined as values at or under the 25th percentile, and reduced MTP was defined as the lowest tertile of the study population (<158.0 cm and <26.5 kPa for men, <145.0 cm and <24.1 kPa for women). Results: Independent of classical cardiovascular risk factors, short stature was revealed to be positively associated with reduced MTP. The adjusted-odds ratio (OR) and 95% confidence interval (CI) of reduced MTP for short stature was 1.87 (1.19, 2.94). We also found that independent of known cardiovascular risk factors, with the non-minor homo of rs3782886 taken as the reference group, the adjusted OR and 95% CI for short stature and reduced MTP of the minor homo allele were 3.06 (1.23, 7.63) and 3.26 (1.33, 8.03), respectively. Conclusion: Short stature is independently associated with reduced MTP, with Asian-specific SNPs possibly playing an important role in this association

Role of receptor kinase in long-term desensitization of the cardiac muscarinic receptor-K⁺ channel system

Desensitization of the cardiac muscarinic K+channel was studied in cultured neonatal rat atrial cells and in Chinese hamster ovary (CHO) cells transfected with muscarinic receptor (HM2), G protein-coupled inward rectifying K+channels 1 and 4, and G protein-coupled receptor kinase 2. In atrial cells incubated in 10 μM carbachol for 24 h, channel activity in cell-attached patches was substantially reduced as a result of long-term desensitization. The long-term desensitization was also observed in CHO cells transfected with the wild-type receptor and receptor kinase (as well as the channel). However, long-term desensitization was greatly reduced or abolished if the cells were 1) not transfected with the receptor kinase, 2) transfected with a mutant receptor lacking phosphorylation sites (rather than the wild-type receptor), or 3) transfected with a mutant receptor kinase lacking kinase activity (rather than the wild-type receptor kinase). We suggest that long-term desensitization of the cardiac muscarinic receptor-K+channel system to muscarinic agonist may involve phosphorylation of the receptor by receptor kinase.</jats:p