Institute of Health and Sport, Victoria University, Melbourne, VIC 8011, Australia.
Department of Physiology, Bosch Institute for Medical Research, University of Sydney, Sydney, NSW 2006, Australia.
Nutrients. 2018 Jun 29;10(7):847. doi: 10.3390/nu10070847.
Recent advances have indicated that osteocalcin, and in particular its undercarboxylated form (ucOC), is not only a nutritional biomarker reflective of vitamin K status and an indicator of bone health but also an active hormone that mediates glucose metabolism in experimental studies. This work has been supported by the putative identification of G protein-coupled receptor, class C, group 6, member A (GPRC6A) as a cell surface receptor for ucOC. Of note, ucOC has been associated with diabetes and with cardiovascular risk in epidemiological studies, consistent with a pathophysiological role for ucOC in vivo. Limitations of existing knowledge include uncertainty regarding the underlying mechanisms by which ucOC interacts with GPRC6A to modulate metabolic and cardiovascular outcomes, technical issues with commonly used assays for ucOC in serum, and a paucity of clinical trials to prove causation and illuminate the scope for novel health interventions. A key emerging area of research is the role of ucOC in relation to expression of GPRC6A in muscle, and whether exercise interventions may modulate metabolic outcomes favorably in part via ucOC. Further research is warranted to clarify potential direct and indirect roles for ucOC in human health and cardiometabolic diseases.
最近的研究进展表明，骨钙素，尤其是其未羧化形式（ucOC），不仅是反映维生素 K 状态和骨骼健康的营养生物标志物，还是一种在实验研究中调节葡萄糖代谢的活性激素。这项工作得到了假定的 G 蛋白偶联受体 C 类家族 6 成员 A（GPRC6A）作为 ucOC 细胞表面受体的鉴定的支持。值得注意的是，在流行病学研究中，ucOC 与糖尿病和心血管风险相关，这与 ucOC 在体内的病理生理作用一致。现有知识的局限性包括：ucOC 与 GPRC6A 相互作用以调节代谢和心血管结局的潜在机制尚不确定、血清中常用的 ucOC 检测方法存在技术问题、以及缺乏临床试验来证明因果关系和阐明新的健康干预措施的范围。一个新兴的研究领域是 ucOC 与肌肉中 GPRC6A 表达的关系，以及运动干预是否可能通过 ucOC 部分有利地调节代谢结局。需要进一步的研究来阐明 ucOC 在人类健康和心血管代谢疾病中的潜在直接和间接作用。
