24-hour profile of serum sclerostin and its association with bone biomarkers in men

Abstract

Purpose The osteocyte exerts important effects on bone remodeling but its rhythmicity and effect on the rhythms of other bone cells are not fully characterized. The purpose of this study was to determine if serum sclerostin displays rhythmicity over a 24-hour (h) interval, similar to that of other bone biomarkers. Methods Serum sclerostin, FGF-23, CTX, and P1NP were measured every 2 hours over a 24-h interval on 10 healthy men aged 20-65 years. Maximum likelihood estimates of the parameters in a repeated measures model were used to determine if these biomarkers displayed a diurnal, sinusoidal rhythm. Results No discernible 24-h rhythm was identified for sclerostin (p = 0.99) or P1NP (p = 0.65). CTX rhythmicity was confirmed (p < 0.001), peaking at 05:30 (range 01:30–07:30). FGF-23 levels were also rhythmic (p < 0.001) but time of peak was variable (range 02:30-11:30). The only significant association identified between these four bone biomarkers was for CTX and P1NP mean 24-h metabolite levels (r = 0.65, p = 0.04). Conclusions Sclerostin levels do not appear to be rhythmic in men. This suggests that in contrast to CTX, serum sclerostin could be measured at any time of day. The 24-h profiles of FGF-23 suggest that a component of osteocyte function is rhythmic but its timing is variable. Our results do not support the hypothesis that osteocytes direct the rhythmicity of other bone turnover markers (CTX), at least not via a sclerostin mediated mechanism.

Melatonin is a potential drug for the prevention of bone loss during space flight

“…Studies have reported molecular links between circadian clocks and bone metabolism in mammals, including humans . For example, in humans, levels of the C‐terminal cross‐linked telopeptide of type I collagen (a bone resorption marker) and fibroblast growth factor 23 (a regulator of mineral metabolism) display a circadian rhythm . On the basis of these findings, one important issue we raised was whether goldfish scales have circadian clock machinery.…”

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

“…Bone metabolism exhibits daily patterns, represented by circadian rhythmicity, of bone turnover markers. In a study including 10 healthy men, the bone resorption marker C-terminal cross-linked telopeptide of type I collagen (CTX) displayed a diurnal rhythm, peaking at 05:30 (range 01:30 – 07:30) [ 18 ], which was consistent with previous studies [ 19 , 20 ]. FGF23, a component of osteocyte function, also showed rhythmicity [ 21 ].…”

Plasma sclerostin levels are associated with nutritional status and insulin resistance but not hormonal disturbances in women with polycystic ovary syndrome

“…So far, a 24-h profile of sclerostin secretion has been evaluated in a single study, in men only. This study showed no diurnal changes in sclerostin levels [24]. However, to exclude the potential effect of a glucose load, sclerostin levels are measured in fasting state [25].…”