Milk proteins and their derived peptides on bone health: Biological functions,mechanisms, and prospects

Bone is a dynamic organ under constant metabolism (or remodeling), where a delicate balance between bone resorption and bone formation is maintained. Disruption of this coordinated bone remodeling results in bone diseases, such as osteoporosis, the most common bone disorder characterized by decreased bone mineral density and microarchitectural deterioration. Epidemiological and clinical evidence support that consumption of dairy products is beneficial for bone health; this benefit is often attributed to the presence of calcium, the physiological contributions of milk proteins on bone metabolism, however, are underestimated. Emerging evidence highlighted that not only milk proteins (including individual milk proteins) but also their derived peptides positively regulate bone remodeling and attenuate bone loss, via the regulation of cellular markers and signaling of osteoblasts and osteoclasts. This article aims to review current knowledge about the roles of milk proteins, with an emphasis on individual milk proteins, bioactive peptides derived from milk proteins, and effect of milk processing in particular fermentation, on bone metabolism, to highlight the potential uses of milk proteins in the prevention and treatment of osteoporosis, and, to discuss the knowledge gap and to recommend future research directions.     

大豆异黄酮对去卵巢大鼠骨质疏松症的实验研究

用切除大鼠卵巢方法建立骨质疏松症模型，研究大豆异黄酮对去卵巢大鼠骨质疏松症的防治作用。结果表明：大豆异黄酮明显增加去卵巢大鼠骨密度，改进子宫指数和血清雌二醇水平及明显降低碱性磷酸酶活性，从而降低骨的转换率和增加骨密度。     

南极磷虾油、鱼油与花生四烯酸油对骨质疏松症小鼠脂质代谢的影响

目的：比较南极磷虾油、鱼油和花生四烯酸油对去卵巢骨质疏松小鼠脂质代谢的影响。方法：对8 周龄健康雌性C57BL/6J小鼠部分进行双侧去卵巢手术,建立绝经后骨质疏松症模型;部分不进行去卵巢手术,仅进行开腹腔与缝合的假手术,作为假手术组（生理盐水）。将造模成功的小鼠分为模型对照组（生理盐水）、南极磷虾油组（150 mg/kg mb）、鱼油组（80 mg/kg mb）和花生四烯酸油组（140 mg/kg mb）。连续灌胃12 周后取材,测定骨密度,血清和肝脏中的总胆固醇、甘油三酯水平,肝脏中脂质合成相关基因表达水平等相关指标。结果：两种n-3多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）油脂南极磷虾油和鱼油能极显著降低骨质疏松小鼠体脂比（P＜0.01）,改善血脂及肝脏脂质水平,显著或极显著下调肝脏中脂质合成关键基因SREBP-1c、FAS、ACC、SCD1的mRNA表达（P＜0.05、P＜0.01）;而n-6 PUFA油脂花生四烯酸油会升高血脂水平并上调肝脏中脂质合成关键基因的表达。结论：两种n-3 PUFA均能够显著改善骨质疏松小鼠脂代谢紊乱,且南极磷虾油效果更好;而n-6 PUFA花生四烯酸油则加剧脂代谢紊乱。     

镉暴露对人体骨骼影响的研究进展

镉是一种环境重金属污染物,在环境中不能进行生物降解,在人体内半衰期长达10-30年。骨骼是镉的重要靶器官,已有研究证实镉是诱发骨密度降低和骨质疏松症发生的危险因素之一。本文综述了镉暴露对人体骨骼影响的国内外相关文献。结果表明,镉暴露对人体骨骼的影响因目标人群的不同而存在差异,且主要受影响人群为中老年人,因此研究时应对目标人群进行合理分组,将镉污染区内尿镉浓度较高的人群划分为高暴露组较为合适。此外,高钙摄入量是人体骨密度的保护因素,但是目前罕有研究将目标人群的钙摄入量的状况和镉暴露状况相结合考虑,这可能造成了对镉暴露所致骨质疏松症和骨折的风险的高估,研究中应一同考虑目标人群的钙摄入量状况,才能对镉暴露所致骨质疏松症和骨折的风险作出正确评估。     

从内分泌激素探讨多囊卵巢综合征诱发骨代谢异常的研究进展

多囊卵巢综合征（polycystic ovary syndrome, PCOS）是女性常见的一种内分泌代谢性疾病。临床研究发现PCOS患者多伴有骨代谢异常、甚至有较高的发生骨质疏松与骨折的风险。本文梳理了PCOS与骨质疏松症发生的共性病因,并着重从内分泌激素（胰岛素、雄激素、生长激素、维生素D、甲状旁腺激素与降钙素）调控的角度,阐述PCOS诱发骨代谢异常的研究进展,以期为PCOS患者骨骼健康的监测与干预提供新的思考。     

The V-ATPase a3 Subunit: Structure,Function and Therapeutic Potential of an Essential Biomolecule in Osteoclastic Bone Resorption

This review focuses on one of the 16 proteins composing the V-ATPase complex responsible for resorbing bone: the a3 subunit. The rationale for focusing on this biomolecule is that mutations in this one protein account for over 50% of osteopetrosis cases, highlighting its critical role in bone physiology. Despite its essential role in bone remodeling and its involvement in bone diseases, little is known about the way in which this subunit is targeted and regulated within osteoclasts. To this end, this review is broadened to include the three other mammalian paralogues (a1, a2 and a4) and the two yeast orthologs (Vph1p and Stv1p). By examining the literature on all of the paralogues/orthologs of the V-ATPase a subunit, we hope to provide insight into the molecular mechanisms and future research directions specific to a3. This review starts with an overview on bone, highlighting the role of V-ATPases in osteoclastic bone resorption. We then cover V-ATPases in other location/functions, highlighting the roles which the four mammalian a subunit paralogues might play in differential targeting and/or regulation. We review the ways in which the energy of ATP hydrolysis is converted into proton translocation, and go in depth into the diverse role of the a subunit, not only in proton translocation but also in lipid binding, cell signaling and human diseases. Finally, the therapeutic implication of targeting a3 specifically for bone diseases and cancer is discussed, with concluding remarks on future directions.     

氟的测定方法及其在内蒙古地氟病防治中的应用

讨论了氟离子的测定方法，并对其在内蒙古地氟病防治中心的应用作了简单介绍。     

基于超声导波反演参数定征皮质骨骨质状况研究

骨质疏松发生时，人体皮质骨层的孔隙度将增大。为研究皮质骨参数（厚度、横波速度、纵波速度）与骨质疏松症的关系，文章利用有限元方法对不同孔隙度（0∶3%∶27%）的单层皮质骨进行仿真，以3个周期的高斯包络正弦波作为激励，将采集到的超声导波信号先后经过二维傅里叶变换和Burg算法处理后得到频散数据，与基于FloquetBloch理论建立的理论频散曲线数据库进行匹配反演，得到皮质骨厚度、横波速度、纵波速度参数。结果显示皮质骨厚度反演准确，皮质骨孔隙度与横波速度和纵波速度呈负相关，横波速度敏感度为19.0%，纵波速度敏感度为5.5%。横波速度敏感度更高，临床诊断潜力更大。并对6组牛胫骨进行了离体实验，结果显示，反演得到的皮质骨厚度与其实际测量值的平均相对误差为4.0%，且实验频散曲线与理论频散曲线相吻合，验证了文中算法在真实皮质骨参数反演上的可行性和准确性。文中的研究在骨质疏松超声检测中具有应用潜力。