In the Search for Associations between Bone and Fat Tissues in the Control of Glucose Homeostasis: Role of Osteocalcin, Bone Resorption and Leptin, in Normoglycemic Nondiabetic Women

BONANNO MARINA SOLEDAD; MARIANA SEIJO; ZENI CORONEL EM; MAROTE C; ZAGO L; OLIVERI B; BRITO G; -ZENI SN

Nutrition And Food Science Journal

SM Online Scientific Resources.

Año: 2022 vol. 5 p. 140 - 154

2833-440X

Background: Osteocalcin (OCN) is involved in controlling glucose homeostasis bystimulating insulin (Ins) and adiponectin production and secretion through the undercarboxylated (uc) form of OCN. Through the sympathetic nervous system, leptininhibits bone formation, increases RANKL production and the resortive activity ofosteoclasts, regulating the bioactivation of OCN. Differences in body mass, estrogenicstatus, vitamin D (VD) and calcium (Ca) nutritional status might affect bone and fatinterrelationship.Study aim: The present cross-sectional study explores this relationship innormoglucemic non-diabetic pre (nM) and postmenopausal (PM) women.Methods: Women (n=484) that met the inclusion criteria were included in the study.Results: When only normal-weight women, were evaluated, total (t) OCN and ucOCNlevels were 17.6±9.5 ng/mL and 1.0±0.8 ng/mL (0.15-4.95 ng/mL) in nM, and20.6±8.9 ng/mL and 1.6±1.1 ng/mL (0.24-3.81 ng/mL) in PM women. In line with thefact that most circulating protein factors associated with regulatory functions areinactive, the mean percentage of ucOCN/tONC was 5% and 8% for nM and PM.When all the studied women having different BMI were included in the analysis, themean values for tOCN showed a slight increase (26.4±9.5 ng/mL and 27.1±9.8ng/mL in nM and PM, respectively), while ucOCN increased significantly (2.5±1.9ng/mL and 2.9±1.7 ng/mL in nM and PM, respectively). As a result ucOCN/tOCNshowed a significant increase with obesity, similar to that observed in Ins resistance,suggesting that fat mass may induce not only Ins resistance but also a certain degreeof resistance to the hormonal form of OCN.Conclusion: As obesity increases, higher circulating ucOCN related to tOCN levelsare necessary to maintain glucose homeostasis. Then, obesity appears to induce acertain degree of resistance to OCN endocrine action. In ucOCN action the adequacyof Ca and VD nutritional status plays an important role.