Bone as an endocrine organ: the biological role and mechanisms of action of osteocalcin in the vasculature

该小型项目将解决两个目标：（1）骨钙素在人类肠系膜动脉中的直接血管效应，以及（2）骨钙素对内皮细胞的影响。(1)使用钢丝肌造影术（O 'Sullivan等人，二○ ○四年;二○ ○五年;二○ ○六年; 2009）在人肠系膜动脉中，我们将检查骨钙素是否引起预收缩动脉的血管舒张或当应用于基线张力时引起动脉的血管收缩。我们还将在生理学上研究骨钙素的生理相关浓度对随后的血管舒张功能的影响，通过将动脉暴露于骨钙素，预收缩血管，然后对内皮依赖性和非依赖性血管舒张药进行浓度响应曲线。还将检查骨钙素对去甲肾上腺素、血管紧张素II和内皮素-1的血管收缩反应的影响。 (2)迄今为止没有研究检查骨钙素对内皮细胞的作用，尽管最近的研究表明骨钙素通过缺氧诱导因子1信号传导刺激VSMC中骨软骨形成转录因子的表达（Idelevich等人，2011年）。学生将研究骨钙素对人内皮细胞系的影响，以确定骨钙素是否影响内皮细胞功能的一些特征，包括内皮细胞增殖（MTT测定），细胞毒性（LDH测定），血管粘附分子，vCAM（通过ELISA）的表达和钙化标志物（ALP含量或钙染色）。

The mini project will address two aims; (1) what are the direct vascular effects of osteocalcin in human mesenteric arteries, and (2) what are the effects of osteocalcin on endothelial cells. (1) Using wire myography (O'Sullivan et al., 2004; 2005; 2006; 2009) in human mesenteric arteries we will examine whether osteocalcin causes vasorelaxation of pre-constricted arteries or causes vasoconstriction of arteries when applied to baseline tone. We will also examine physiologically the effect of physiologically-relevant concentrations of osteocalcin on subsequent vasodilator function by exposing arteries to osteocalcin, pre-constricting pharmacologically and then performing concentration responses curves to endothelium-dependent and independent vasorelaxants. The effect of osteocalcin on vasoconstrictor responses to noradrenaline, angiotensin II and endothelin-1 will also be examined. (2) No studies to date have examined the effects of osteocalcin on endothelial cells, although a recent study suggested that osteocalcin, via hypoxia-inducible factor 1 signalling, stimulates expression of osteochondrogenic transcription factors in VSMCs (Idelevich et al., 2011). Students will investigate the effects of osteocalcin on a human endothelial cell line to establish whether osteocalcin affects a number of features of endothelial cell function, including endothelial cell proliferation (MTT assay), cytotoxicity (LDH assay), the expression of vascular adhesion molecule, vCAM (by ELISA), and markers of calcification (ALP content or calcium staining).