快速衰老小鼠的Klotho表达与β淀粉样肽清除的相关性研究

目的 探讨快速衰老小鼠(SAMP8)中Klotho低表达对β淀粉样肽(Aβ)清除的影响.方法 采用Y迷宫和跳台实验评测12月龄SAMP8小鼠和抗衰老系列小鼠(SAMR1)的学习和空间记忆能力;免疫组化检测小鼠脑中Aβ1-42、同种异体移植炎性因子-1(AIF1)、胶质纤维酸性蛋白(GFAP)和Klotho的变化;蛋白免疫印迹法检测低密度脂蛋白受体相关蛋白(LRP-1)、晚期糖基化末端产物(RAGE)的蛋白表达.结果 与SAMR1小鼠相比,SAMP8小鼠的学习、记忆功能明显下降,脑内Aβ1-42、AIF1、GFAP和RAGE的表达显著增加,Klotho和LRP-1的表达明显降低.结论 SAMP8小鼠中Klotho表达的降低可能导致LRP-1降低和RAGE增加,从而增加Aβ在脑内沉积.     

Wnt10b与骨形态发生蛋白9诱导间充质干细胞成骨分化的关系

目的研究Wnt10b与骨形态发生蛋白9(BMP9)诱导间充质干细胞(MSCs)骨向分化的关系,以及相关的分子机制。方法利用PCR、Western blot、组织化学染色等方法,检测BMP9对Wnt10b表达的影响,以及Wnt10b对BMP9诱导的成骨分化的影响。同时,通过定量PCR、Western blot、油红O染色、流式细胞术等,分析Wnt10b影响BMP9成骨分化诱导作用的可能机制。结果 Wnt10b在C3H10T1/2、C2C12、MEFs和MC3T3-E1细胞中均有表达,BMP9在C3H10T1/2细胞中上调Wnt10b的表达水平。Wnt10b增强BMP9在C3H10T1/2细胞中增加OCN蛋白水平和促进钙盐沉积的能力,沉默Wnt10b减弱BMP9的作用。Wnt10b并不改变BMP9对细胞周期的影响,但能增强BMP9诱导的Smad1/5/8磷酸化,沉默Wnt10b减弱BMP9对Smad1/5/8磷酸化的促进作用。此外,Wnt10b抑制BMP9在C3H10T1/2细胞中诱导的成脂分化,沉默Wnt10b则促进BMP9的成脂分化诱导作用。结论 Wnt10b可以促进BMP9诱导的MSCs骨向分化,这种作用可能与增强BMP/Smad信号转导有关。     

温补肾阳单味中药及其有效成分防治骨质疏松症的可能分子机制研究进展

骨质疏松症(osteoporosis,OP)是一种代谢性骨病,以骨量下降、骨微结构损坏为主要临床特征,发病率呈现逐渐上升的趋势。中医学将OP纳入“骨痿”“骨枯”“骨极”等疾病范畴,中医药被用于治疗OP由来已久,具有简、便、廉、验等优势。随着中西医结合医学学科的深入融合发展,基础研究发现多种温补肾阳类单味中药及其有效成分可能通过调控Wnt/β-连环蛋白(β-catenin)、骨形态生成蛋白(BMP)/Smads、磷脂酰肌醇-3磷酸激酶/AKT/雷帕霉素靶蛋白信号通路(PI3K/Akt/mTOR)等骨代谢相关信号通路以达到防治OP的目的,这有可能从分子机制上肯定了中医药治疗OP的科学性。该文综述杜仲、骨碎补等常见代表性温补肾阳类中药及其有效成分防治OP的可能分子机制,以期为中医药临床治疗OP的进一步研究应用提供参考。     

首个骨硬化蛋白抑制剂——罗莫珠单抗

骨硬化蛋白(sclerostin)是SOST基因表达的一种分泌蛋白,可与低密度脂蛋白受体相关蛋白5/6结合,阻断Wnt/β-catenin信号通路,降低成骨细胞的成骨作用,导致骨密度降低,骨脆性增加。抑制sclerostin活性可拮抗其对骨代谢的负向调节作用,促进骨形成的同时抑制骨吸收。罗莫珠单抗(商品名Evenity)是由安进公司和优时比公司共同研发的全球首个sclerostin抑制剂。临床试验结果表明,罗莫珠单抗能够快速增加骨密度,降低骨折发生率,是目前唯一一个兼具双重作用的骨质疏松治疗药物。本文对其作用机制、药物代谢动力学、临床评价、安全性等信息进行综述,旨在为临床用药提供参考。     

骨形态发生蛋白9诱导间充质干细胞骨向分化与Wnt11的关系

目的探讨骨形态发生蛋白9(BMP9)诱导干细胞骨向分化与Wnt11的关系及可能的分子机制。方法通过q PCR、组织化学染色及Western blot等方法,检测成骨分化相关标志物,以及BMP/Smad和p38 MAPK信号的变化;利用荧光素酶报告质粒,检测BMP/Smad信号的活性改变。结果BMP9增加C3H10T1/2细胞中碱性磷酸酶(ALP)活性、钙盐沉积、骨桥素(OPN)和Wnt11表达。Wnt11在C3H10T1/2、MEFs、MC3T3-E1和C2C12细胞中均有表达。在C3H10T1/2细胞中,Wnt11增强BMP9促进ALP活性、钙盐沉积、Runx-2和OPN表达的作用,以及BMP9对BMP/Smad报告质粒转录活性和Smad1/5/8磷酸化的促进作用;Wnt11还增强BMP9诱导p38 MAPK磷酸化的作用;抑制p38 MAPK则减弱BMP9诱导ALP活性、钙盐沉积及OPN表达的作用,但该效应能被Wnt11部分逆转。结论 BMP9在MSCs中能上调Wnt11表达。Wnt11能促进BMP9的骨向分化诱导作用,该作用可能与其增加BMP/Smad和p38 MAPK信号的活性有关。     

血清甲状旁腺素和降钙素水平对骨代谢影响的临床研究

骨质疏松症(osteoporosis,OP)是一种以骨量降低、骨组织微结构破坏、骨脆性增加及易发生骨折为特征的全身性代谢性疾病。2001年由美国国立卫生研究院(NIH)提出OP的定义为以骨强度下降和骨折风险增加为特征的骨骼系统疾病,骨强度反映骨骼的2个方面,即骨质量及骨矿密度。根据世界卫生组织(WHO)分类,OP有3种类型,包括原发性OP、继发性OP和特发性OP。     

非编码RNA调控骨质疏松症骨重建机制及补肾壮骨类中医药治疗机制研究进展

非编码RNA (non-coding RNAs,ncRNAs)是一种缺乏蛋白编码功能但可以影响染色体结构、基因转录及参与表观遗传调控的特殊RNA,主要包括长链非编码RNA、微小RNA等。近年来研究发现,这些ncRNAs主要通过影响骨质疏松(osteoporosis,OP)的骨吸收与骨形成来维持其骨重建。明确ncRNAs在OP发生发展中的调控机制可能是未来治疗OP药物药效筛选的关键靶点。由于中医将OP归属于“骨痹”范畴,根据中医的“肾主骨生髓”理论,临床主要采用补肾壮骨类方药来治疗OP,且疗效显著。已有研究发现,补肾壮骨类方药可通过上调或下调ncRNA的表达来增强成骨细胞增殖或抑制破骨细胞分化,最终维持了OP骨稳态,从而发挥疗效,但其具体分子机制仍处于探索阶段。故本文通过总结近年来补肾壮骨类方药通过调控ncRNAs治疗OP的分子机制,以期为治疗OP药物药效关键靶点的筛选和中医药防治OP提供新思路。     

骨质疏松性骨折的诊治进展

骨质疏松症（osteoporosis,OP）是一种以骨量低下,骨微结构破坏,导致骨脆性增加,易发生骨折为特征的全身性骨病。骨质疏松性骨折是OP最严重的后果,属脆性骨折,由于骨强度下降,轻微创伤或日常活动中即可发生,一般轻微暴力可造成的骨折。此类骨折属完全性骨折,在老年人中常见,     

rhPTH(1-34)防治糖皮质激素骨质疏松症的机制研究

目的:建立糖皮质激素性骨质疏松症(GIOP)大鼠模型及其提取BMSCs,检测甲状旁腺激素相关肽(1-34)(rhPTH(1-34))干预下对成骨及Wnt/β-catenin相关蛋白的影响。方法:SPF级雄性大鼠随机均分为正常对照组、甲强龙组(模型组)、甲强龙+生理盐水组(空白对照组)和甲强龙+rhPTH(1-34)组(试验组)。提取模型BMSCs,以BMP-2诱导为对照并经rhPTH(1-34)干预后,测定成骨分化相关基因ALP、Runx~2、OCN表达、测定Wnt3a、β-catenin蛋白表达及β-catenin/TCF转录水平。结果:rhPTH(1-34)干预后:(1)成骨指标ALP、Runx~2、OCN显著增加(P0.05);(2)β-catenin/TCF转录活性、Wnt3a、β-catenin蛋白表达显著增加(P0.05)。结论:rhPTH(1-34)能够调控Wnt/β-catenin信号通路促进成骨进而防治GIOP。     

Wnt/Dkk在骨改建中对成骨细胞和破骨细胞的双向调节作用

Wnt信号通路是目前骨骼系统相关疾病发病机制和骨代谢研究的新热点.Wnt信号通路作用于骨,主要表现为对骨组织细胞,特别是对成骨细胞和破骨细胞功能的调节.研究发现,诱导Wnt家族成员表达可使成骨细胞特异性基因表达增加,促进骨形成;Dkk为Wnt通路的抑制因子,它的表达上调可使成骨细胞数量减少,抑制骨形成;Wnt信号通路在作用于成骨细胞的基础上可间接调节破骨细胞的功能变化.     

Role of advanced glycation end products (AGEs) in osteoporosis in diabetes

Recent meta-analyses have revealed that the risk of bone fracture is increased in both type 1 and type 2 diabetic patients. Low bone mineral density (BMD) can not necessarily explain the link, because BMD is increased rather than decreased in type 2 diabetes, while it is consistently low in type 1 diabetes subjects. Although multiple factors could influence the quality of bone and increase the bone fragility in diabetes, there is accumulating evidence for the association between osteoporosis and vascular calcification, which is an independent predictor of cardiovascular disease morbidity and mortality. Advanced glycation end products (AGEs) are formed by a non-enzymatic reaction between aldehydes of reducing sugars and the amino groups of proteins, lipids and nucleic acids that could contribute to the aging of macromolecules. The formation and accumulation of AGEs have been known to progress at an accelerated rate under diabetes. There is a growing body of evidence that AGEs and their receptor (RAGE) system elicit oxidative stress generation and subsequently evoke inflammatory responses in vascular wall cells, osteoblasts and osteoclasts, thereby being involved in both vascular calcification and osteoporosis in diabetes. Further, cross-linking in the organic bone matrix by AGEs could adversely affect the fracture resistance of bone. Therefore, in this paper, I review the pathophysiological role of the AGEs-RAGE-oxidative stress system in decreased BMD and increased bone fragility in diabetes. I also discuss here the potential therapeutic interventions of the AGEs-RAGE axis for preventing osteoporosis in diabetes.     

The effect of alendronate on the expression of osteopontin and osteoprotegerin in calcified aortic tissue of the rat

Vascular calcification is a pathobiological process which leads to high morbidity and mortality in cardiovascular disease. The association between vascular calcification and osteoporosis has been reported widely, and there are close relationships among vascular calcification, related cardiovascular disease and osteoporosis, but the biochemical mechanism of vascular calcification is presently unclear. For exploring the possible mechanism of artery calcification we established aorta calcification in an animal model with vitamin D(3) and warfarin and tested the effect of alendronate on the expression of osteopontin and osteoprotegerin in calcified aorta tissue of the rat through measuring gene and protein expression of osteopontin and osteoprotegerin respectively. The results indicated compared with control group, the aortic calcium content of calcification group was obviously increased, osteopontin mRNA and osteoprotegerin mRNA were significantly reduced, and osteoprotegerin and osteopontin protein expressions were reduced. Compared with calcification group, the aortic calcium content of alendronate group was obviously reduced, osteopontin mRNA and osteoprotegerin mRNA were significantly increased, and osteopontin and osteoprotegerin protein expression were increased. We conclude that artery calcification may reduce the expression of osteopontin and osteoprotegerin. Alendronate may inhibit rat aorta calcification by up-regulating osteopontin and osteoprotegerin expression.     

Vascular Calcification,Vitamin K and Warfarin Therapy – Possible or Plausible Connection?

Atherosclerosis is a pathological process underpinning many cardiovascular diseases; it is the main cause of global mortality. Atherosclerosis is characterized by an invasion of inflammatory cells, accumulation of lipids and the formation of fatty streaks (plaques) which subsequently allow accumulation of calcium and other minerals leading to a disturbance in the vascular endothelium and its regulatory role in arterial function. Vascular calcification is a different process, stringently regulated mainly by local factors, in which osteoblast‐like cells accumulate in the muscular layer of arteries ultimately taking on the physiological appearance of bone. The elevated stiffness of the arteries leads to severe vascular complications in brain, heart and kidneys. Recently, evidence from animal experiments as well as clinical and epidemiological results suggests that long‐term treatment with warfarin, but not with the novel direct anticoagulants, can increase the risk or even induce vascular calcification in some individuals. Gamma‐carboxylation is an enzymatic process not only needed for activation of vitamin K but also other proteins which participate in bone formation and vascular calcification. Thus, reduced expression of the vitamin K‐dependent proteins which physiologically inhibit calcification of cellular matrix could be postulated to lead to vascular calcification. Published clinical data, describing at present a few thousand patients, need to be supplemented with controlled studies to confirm this interesting hypothesis.     

慢性肾脏病患者血管钙化的病理机制研究进展

在慢性肾脏病（chronic kidney disease,CKD）患者中,肾功能的进行性降低导致矿物质代谢紊乱、酸中毒、营养不良、炎症和尿毒症毒素积累等症状,可引起继发性甲状旁腺功能亢进、血清钙升高、磷酸盐水平升高和血清成纤维细胞生长因子-23（fibroblast growth factor-23,FGF-23）升高,由此产生CKD相关的矿物质和骨代谢紊乱,循环中过量的钙和磷酸盐也可以促进蛋白质-矿物质复合物的形成,称为钙蛋白颗粒（calpain particles,CPPs）,在CKD中,这些CPPs含有较少的钙化抑制剂,诱发炎症,并促进血管平滑肌细胞的钙化。由此促进血管钙化的发生。诸多横断面观察研究表明,血清FGF-23水平在CKD早期（1~2期）开始升高,并与肾小球滤过率呈负相关,促进血管钙化,最新的研究表明高水平脂联素对FGF-23在冠状动脉钙化的作用中起调节作用。本文综述了CKD患者血管钙化发展机制的研究进展,为进一步寻找潜在的新治疗目标指出方向。     

Arsenic induces cell apoptosis in cultured osteoblasts through endoplasmic reticulum stress

Osteoporosis is characterized by low bone mass resulting from an imbalance between bone resorption by osteoclasts and bone formation by osteoblasts. Therefore, decreased bone formation by osteoblasts may lead to the development of osteoporosis, and rate of apoptosis is responsible for the regulation of bone formation. Arsenic (As) exists ubiquitously in our environment and increases the risk of neurotoxicity, liver injury, peripheral vascular disease and cancer. However, the effect of As on apoptosis of osteoblasts is mostly unknown. Here, we found that As induced cell apoptosis in osteoblastic cell lines (including hFOB, MC3T3-E1 and MG-63) and mouse bone marrow stromal cells (M2-10B4). As also induced upregulation of Bax and Bak, downregulation of Bcl-2 and dysfunction of mitochondria in osteoblasts. As also triggered endoplasmic reticulum (ER) stress, as indicated by changes in cytosolic-calcium levels. We found that As increased the expression and activities of glucose-regulated protein 78 (GRP78) and calpain. Transfection of cells with GRP78 or calpain siRNA reduced As-mediated cell apoptosis in osteoblasts. Therefore, our results suggest that As increased cell apoptosis in cultured osteoblasts and increased the risk of osteoporosis.     

血清骨钙素水平与老年骨质疏松及冠状动脉病变的相关性

目的探讨血清骨钙素水平与老年骨质疏松及冠状动脉病变的相关性。方法选取183例年龄在60-85岁的患者，根据骨密度测定结果分为2组：非骨质疏松组86例，骨质疏松组97例；根据冠状动脉螺旋CT检查结果分为3组：轻度钙化组（积分〈200）68例；中度钙化组（200≤积分〈300）43例；重度钙化组（积分I〉300）72例。比较各组患者的冠状动脉狭窄病变和钙化程度。应用酶联免疫吸附试验者测定各组患者血清骨钙素水平。结果骨质疏松组患者合并肥胖、高血压、高血脂和糖尿病的比例分别为56．7％（55／97）、80．4％（78／97）、78．4％（76／97）、71．1％（69／97），高于非骨质疏松组的37．2％（32／86）、54．7％（47／86）、44．2％（38／86）、31．4％（27／86）（P〈0．05）；骨质疏松组患者血清骨钙素水平明显低于非骨质疏松组患者[（14．4±3）ng／L比（424±6）ng／L（P〈0．05）]；骨质疏松组患者任意冠状动脉分支的钙化程度均高于非骨质疏松组，2组比较差异有统计学意义（P〈0．05）。骨质疏松组冠状动脉单支病变超过50％狭窄者比例明显高于非骨质疏松组，冠状动脉2支以上病变者占比更高[20．6％（20／97）比3．5％（3／86）]，差异均有统计学意义（均P〈0．05）。冠状动脉血清骨钙素水平分别为（45．6±8．3）、（26．2±4．8）、（15．5±10．2）ng／L，任意两两比较差异均有统计学意义（均P〈0．01）。结论骨钙流失与钙质在冠状动脉的沉积存在共同的发病机制。该机制与血清骨钙素水平有关，血清骨钙素对老年男性骨质疏松与冠状动脉钙化有保护作用。     

Phosphate: an old bone molecule but new cardiovascular risk factor

Phosphate handling in the body is complex and involves hormones produced by the bone, the parathyroid gland and the kidneys. Phosphate is mostly found in hydroxyapatite. however recent evidence suggests that phosphate is also a signalling molecule associated with bone formation. Phosphate balance requires careful regulation of gut and kidney phosphate transporters, SLC34 transporter family, but phosphate signalling in osteoblasts and vascular smooth muscle cells is likely mediated by the SLC20 transporter family (PiT1 and PiT2). If not properly regulated, phosphate imblanace could lead to mineral disorders as well as vascular calcification. In chronic kidney disease-mineral bone disorder, hyperphosphataemia has been consistently associated with extra-osseous calcification and cardiovascular disease. This review focuses on the physiological mechanisms involved in phosphate balance and cell signalling (i.e. osteoblasts and vascular smooth muscle cells) as well as pathological consequences of hyperphosphataemia. Finally, conventional as well as new and experimental therapeutics in the treatment of hyperphosphataemia are explored.     

药物干预类风湿性关节炎骨代谢紊乱的研究进展

类风湿性关节炎（RA）骨代谢紊乱可导致骨密度降低及骨脆性增加,一方面可能是由于疾病本身的炎症环境及免疫异常引起,另一方面糖皮质激素等药物的干预也可能加重骨质疏松的发生。RA骨代谢紊乱随着病程进展及炎症反应呈进行性加重,早期可表现有关节软骨破坏及骨端骨质疏松,晚期可累及四肢、腰椎的骨密度降低脆性增加,甚至全身性骨质疏松的发生。明确RA骨破坏特点对RA骨代谢紊乱的诊断及针对性防治具有重要作用,对改善风湿病患者的生活质量及疾病控制具有重要意义。综述了近年RA骨代谢异常及药物干预相关研究进展,首先从骨代谢紊乱的发病率、累及的不同骨组织以及可能发病机制对RA骨代谢紊乱的表现进行了总结,在此基础上从缓解RA病情药物、生物制剂以及中医药防治RA骨代谢紊乱作用进行了药物干预现状的总结,以期为RA骨破坏的治疗提供一定参考。     

New concept of vascular calcification and metabolism

Vascular calcification is recently considered as one of the major complications and an independent risk factor of cardiovascular diseases. Although vascular calcification was commonly regarded as a passive process of mineral adsorption or precipitation, it tends to be an active process associated with the expression of growth factors, matrix proteins, and other bone-related proteins. There are 2 main types of vascular calcification. Intimal calcification is found in atherosclerotic plaques and is associated with the vascular events such as myocardial infarction. Medial calcification is usually associated with age and chronic kidney disease patients, which leads to increased vascular stiffness and reduced vascular compliance. Interestingly, our vascular calcification model using ApoE deficient mice showed intima calcification at sites of atherosclerotic plaques under high fat diet with ovariectomy. Thus, lipid metabolism is one of the therapeutic targets to prevent intima calcification of aorta. Previously we reported that ezetimibe significantly prevented atherosclerosis through lipid-lowering effects in ApoE-deficient mice. Based on these findings, we speculate that ezetimibe might prevent aortic intima calcification, which may give us the benefits to decrease vascular events.     

Hyperphosphatemia and phosphate binders: effectiveness and safety

In patients with kidney dysfunction hyperphosphatemia is more evident as renal failure progresses. It is related to increased FGF-23 levels, secondary hyperparathyroidism, and accelerated progressive vascular calcification. In CKD patients advanced coronary artery calcification is strongly associated with future cardiovascular events, cardiovascular death, and all-cause mortality. Apart from the above, phosphate per se is suspected as a causal risk factor for CKD progression. Keeping serum phosphorus within the target values are linked to improvement in life expectancy. A low phosphate diet, an efficient dialysis removal of phosphate load, and the administration of phosphate binders are the main recommended steps to control hyperphosphatemia. Calcium-based phosphate binders can lead to a positive calcium balance, hypercalcaemia, parathyroid gland suppression, adynamic bone disease, and coronary artery and aortic calcification. On the other hand Sevelamer hydrochloride and Lanthanum carbonate has been shown to be effective, safe and useful therapeutic tools for hyperphosphatemia. When prescribe pharmacological agents, one must take into account the large increase in health-care expenditure and the choice of phosphate binder should be individualized.