Associations between vitamin D-binding protein (DBP) gene polymorphism (TAAA)n and development of osteoporosis in the Volga-Ural region of Russia

Insights into the Role of Circadian Rhythms in Bone Metabolism: A Promising Intervention Target?

Numerous physiological processes of mammals, including bone metabolism, are regulated by the circadian clock system, which consists of a central regulator, the suprachiasmatic nucleus (SCN), and the peripheral oscillators of the BMAL1/CLOCK-PERs/CRYs system. Various bone turnover markers and bone metabolism-regulating hormones such as melatonin and parathyroid hormone (PTH) display diurnal rhythmicity. According to previous research, disruption of the circadian clock due to shift work, sleep restriction, or clock gene knockout is associated with osteoporosis or other abnormal bone metabolism, showing the importance of the circadian clock system for maintaining homeostasis of bone metabolism. Moreover, common causes of osteoporosis, including postmenopausal status and aging, are associated with changes in the circadian clock. In our previous research, we found that agonism of the circadian regulators REV-ERBs inhibits osteoclast differentiation and ameliorates ovariectomy-induced bone loss in mice, suggesting that clock genes may be promising intervention targets for abnormal bone metabolism. Moreover, osteoporosis interventions at different time points can provide varying degrees of bone protection, showing the importance of accounting for circadian rhythms for optimal curative effects in clinical treatment of osteoporosis. In this review, we summarize current knowledge about circadian rhythms and bone metabolism.

Vitamin D-binding protein and its polymorphisms as a predictor for metabolic syndrome

AIM

To investigate the relationship of vitamin D-binding protein (GC) and genetic variation of GC (rs4588, rs7041 and rs2282679) with metabolic syndrome (MetS) in the Thai population.

MATERIALS & METHODS

GC-globulin concentrations were measured by quantitative western blot analysis in 401 adults. All participants were genotyped using TaqMan allelic discrimination assays.

RESULTS

GC-globulin levels were significatly lower in MetS subjects than in control subjects, in which significant negative correlations of GC-globulin levels with systolic blood pressure, glucose and age were found. Male participants who carried the GT genotype for rs4588 showed an increased risk of MetS compared with the GG wild-type (odds ratio: 3.25; p = 0.004).

CONCLUSION

GC-globulin concentrations and variation in GC rs4588 were supported as a risk factor for MetS in Thais.