Osteocalcin, energy and glucose metabolism

Abstract

Osteocalcin is a bone matrix protein that has been associated with several hormonal actions on energy and glucose metabolism. Animal and experimental models have shown that osteocalcin is released into the bloodstream and exerts biological effects on pancreatic beta cells and adipose tissue. Undercarboxylated osteocalcin is the hormonally active isoform and stimulates insulin secretion and enhances insulin sensitivity in adipose tissue and muscle. Insulin and leptin, in turn, act on bone tissue, modulating the osteocalcin secretion, in a traditional feedback mechanism that places the skeleton as a true endocrine organ. Further studies are required to elucidate the role of osteocalcin in the regulation of glucose and energy metabolism in humans and its potential therapeutic implications in diabetes, obesity and metabolic syndrome. Arq Bras Endocrinol Metab. 2014;58(5):444-51 Keywords Osteocalcin; undercarboxylated osteocalcin; metabolic syndrome; glucose; energy metabolism; diabetes; obesity; leptin; insulin; adiponectin RESUMO A osteocalcina é uma proteína da matriz óssea que tem sido implicada com várias ações hormonais relacionadas à homeostase de glicose e ao metabolismo energéti-co. Modelos animais e experimentais têm demonstrado que a osteocalcina é liberada do osso para a circulação sanguínea e age nas células betapancreáticas e no tecido adiposo. A osteocalcina decarboxilada é a isoforma hormonalmente ativa e estimula a secreção e sensibilidade à insulina no tecido adiposo e muscular. A insulina e a leptina, por sua vez, atuam no tecido ósseo modulando a secreção da osteocalcina, formando uma alça de retroalimentação tradicional em que o esqueleto torna-se um órgão endócrino. Novos estudos ainda são necessários para elucidar o papel da osteocalcina na regulação glicêmica e no metabolismo energético em humanos, com potenciais implicações terapêuticas no tratamento de diabetes, obesidade e síndrome metabólica. Arq Bras Endocrinol Metab. 2014;58(5):444-51 Descritores

Relationships between preptin and osteocalcin in obese, overweight, and normal weight adults

“…It remains to be determined whether the administration of osteocalcin in humans will be useful in treating conditions such as obesity and metabolic syndrome (Zanatta et al 2014).…”

The Markers of Bone Metabolism and System Inflammation in Patients With Osteoarthritis Depending on Body Mass, the Influence of Symptomatic Slow Acting Drugs

“…The distinctive feature of the bone tissue remodeling mechanisms at OA is the differences in domination of catabolic or anabolic component depending on the stage of OA development [11]. The study of osteocytes activity invitro demonstrates the bone resorptions at the early OA stages [12,13], with further decrease of their intensity at further OA progressing [14] that is proved by the results of several researches with measuring the level of bone creation and bone resorption markers in the blood serum of patients with OA [15].…”

“…Thus, OC can be considered as the specific marker of functional activity of SCB osteoblasts and the sensitive marker of the bone tissue remodeling. The data that demonstrate the decrease of OC level among patients with obesity and its connection with carbohydrate metabolism disorder are also interesting [15].…”

Correlation of Serum Osteocalcin Level and Periodontal Attachment Loss With Osteoporosis Risk Status in Postmenopausal Women

“…Postmenopausal women with a reduced BMD have a greater tendency for alveolar bone loss and CAL because inflammatory mediators are increased in the systemic and oral bones [9]. Bone turnover can be assessed by measurements of a protein produced by osteoblasts and osteoclasts: Osteocalcin, also known as the bone Gla protein, which is a noncollagenous bone protein [10].…”

“…It is synthesized mainly by osteoblasts as well as a small number of odontoblasts and chondroblasts. After being synthesized, it is stored in the bone mineral matrix as hydroxyapatite crystals and is recognized as a marker of bone formation [10]. Serum osteocalcin is known to be a valid biomarker for detecting a low BMD [12].…”