晚期糖基化终末产物对骨组织细胞代谢的影响

文题释义： 晚期糖基化终末产物：是还原糖(如葡萄糖)和某些代谢产物(如甲基已二醛)与蛋白质氨基经过非酶促反应生成的多种化合物,可以积聚在骨组织中,影响骨组织的结构和力学性能,导致骨强度显著下降。 骨胶原交联：骨胶原分子交联包括有利的酶催化交联(即未成熟的二价交联、成熟的三价交联)和不利的非酶催化交联。在骨组织发育过程中,胶原分子在酶催化的情况下,形成不成熟的二价交联,其中一部分二价交联进一步成熟形成三价交联;而在无酶催化情况下交联反应可形成晚期糖基化终末产物。 背景：随着骨组织工程学的研究和发展,发现晚期糖基化终末产物可以在骨组织中积累,影响骨骼的结构及生物力学性能。目前许多研究发现晚期糖基化终末产物/晚期糖基化终末产物受体通过特殊的作用机制后能够引起以成骨细胞、破骨细胞及骨细胞为主的骨组织细胞发生病理改变,导致骨重建失衡,骨骼强度下降,骨折发生率增加。 目的：综述晚期糖基化终末产物对骨骼生物力学的影响以及晚期糖基化终末产物/晚期糖基化终末产物受体对骨组织细胞的作用机制。 方法：由第一作者检索2005年1月至 2019年 7 月在PubMed、Web of Science 和 Medline数据库发表的有关晚期糖基化终末产物/晚期糖基化终末产物受体对骨组织细胞代谢的影响的文章,检索结果限于英文文献。 结果与结论：最终选取具有代表性的54篇文献进行归纳总结。晚期糖基化终末产物对骨胶原交联的影响,使得骨强度显著下降;晚期糖基化终末产物/晚期糖基化终末产物受体通过使骨组织细胞发生病理机制改变影响骨代谢,使得骨组织细胞发生本质改变。最终导致骨代谢平衡紊乱,骨骼脆性增加。骨质疏松症的发生与骨代谢相关的细胞活力改变有着直接关系,但具体相关作用机制需进一步研究,而这种特殊机制的改变在今后有可能为骨质疏松症提供独特的病理机制、诊断思维和相关治疗及预防策略。 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

晚期糖基化终末产物对骨组织生物力学影响的研究进展

晚期糖基化终末产物（advanced glycation end-products,AGEs）是大分子物质的游离氨基与还原糖之间发生的非酶促反应产物。AGEs在骨组织中积聚会通过与骨组织细胞表面受体的结合改变骨组织细胞活性及功能,引起骨重建过程异常。AGEs积聚还会改变骨胶原原有结构及矿物质沉积,影响骨组织的微观力学性能,造成骨强度及韧性的降低,增加骨折风险,导致骨疾病的发生,危害人体健康。概述AGEs的产生原因及检测方法,并从微观和宏观层面综述AGEs在生物体骨组织内积聚对骨生物力学影响的研究进展,为临床上对骨疾病的早期诊断与治疗提供参考。     

晚期糖基化终末产物单克隆抗体制备与鉴定

目的：制备抗人晚期糖基化终末产物AGEs单克隆抗体（McAb）。方法：孵育D-葡萄糖和人血清白蛋白（HSA）获得AGE-HSA，取凝胶层析纯化后的第1峰AGE—HSA作为免疫原，免疫BALB／c小鼠，采用杂交瘤技术制备抗AGE．HSA的McAb，用间接ELISA和Western blot鉴定其亚类和特异性。结果：成功筛选出3株稳定分泌抗AGE-HSA的McAb杂交瘤细胞株，其分泌抗体亚类为IgM，经Western blot鉴定该McAb特异性高，亲和力强。结论：获得抗人AGE—HSA的McAb细胞株3株，为深入研究AGEs和应用提供了有力工具。     

下调晚期糖基化终末产物受体对乳腺癌细胞增殖、凋亡、侵袭、迁移能力的影响

目的：研究下调晚期糖基化终末产物受体（RAGE）对乳腺癌细胞增殖、凋亡、侵袭、迁移能力的影响。 方法：培养乳腺癌BT474 细胞,分为对照组（ 不做任何处理的乳腺癌BT474 细胞）、上调组（ 乳腺癌BT474 细 胞+RAGE阴性对照）、下调组（ 乳腺癌BT474 细胞+RAGE siRNA）。用四甲基偶氮唑盐法检测乳腺癌细胞增 殖、凋亡水平;用Transwell 法检测乳腺癌细胞迁移、侵袭水平;用免疫印迹法检测细胞PI3K/Akt 信号通路蛋白 PI3K、p-PI3K、Akt、p-Akt、caspase 3、Bcl-2、Bax 表达量。结果：下调组细胞不同时间点增殖率均显著低于 上调组、对照组。下调组细胞不同时间点凋亡率均显著高于上调组、对照组。下调组细胞迁移、侵袭数均显著 低于上调组、对照组。下调组p-PI3K、PI3K、Akt、p-Akt、Bcl-2 蛋白表达量低于上调组、对照组,caspase 3、 Bax 蛋白表达量高于上调组、对照组。结论：经下调RAGE作用于PI3K/Akt 信号通路,其可抑制p-PI3K、PI3K、 Akt、p-Akt、Bcl-2 表达,促进caspase 3、Bax 表达,致乳腺癌细胞凋亡,抑制乳腺癌细胞增殖、侵袭、迁移。     

可溶性晚期糖基化终末产物受体拮抗缺血/再灌注小鼠心肌纤维化

目的 探讨可溶性晚期糖基化终末产物受体（sRAGE）对缺血/再灌注小鼠心脏炎症的影响及其机制。 方法 利用6～8周龄雄性C57BL/6小鼠构建心肌缺血/再灌注损伤模型（左前降支结扎30 min,再灌注2周）,随机分为4组,每组5只C57BL/6小鼠。通过心脏超声检测心功能,HE染色观察炎症细胞浸润情况,马松和天狼星红染色检测心肌纤维化,免疫组织化学染色检测半乳糖凝集素3（galecti-3）表达。 结果 与假手术组相比,缺血/再灌注组小鼠的心功能减退,心肌组织间有大量炎症细胞浸润,心肌纤维化面积增加,同时,心脏组织中 galectin-3 的表达增多;而给予外源性sRAGE处理后,小鼠的心功能显著改善,炎症细胞浸润减少,纤维化程度减轻,心脏组织中galecti-3的表达也显著减少。 结论 心肌缺血/再灌注损伤时,sRAGE可能通过抑制galectin-3的表达,减少小鼠心脏炎症细胞浸润,从而减轻心肌纤维化。     

膝骨关节炎滑液中可溶性晚期糖基化终末产物受体水平与其病变程度的相关性

背景：研究表明骨关节炎患者关节滑液内可溶性晚期糖基化终末产物受体水平可能与关节炎病变的严重程度存在负相关,但在中国报道较少。 目的：观察膝关节骨关节炎患者关节滑液内可溶性晚期糖基化终末产物受体水平与其病变严重程度的关系。 方法：共纳入46名膝关节骨关节炎患者及14名健康对照者,纳入的骨关节炎患者符合美国风湿病学会骨关节炎的临床诊断标准。采用Kellgren-Lawrence的标准对膝关节骨关节炎病变严重程度进行分级,使用人可溶性晚期糖基化终末产物受体水平酶联免疫吸附试剂盒在酶标仪下检测测关节滑液的可溶性晚期糖基化终末产物受体水平。 结果与结论：膝关节骨关节炎患者关节滑液可溶性晚期糖基化终末产物受体水平较健康对照组显著降低(P < 0.01),且与膝关节骨关节炎病变严重程度呈显著独立负相关(r =-0.587,P < 0.01)。结果表明关节滑液可溶性晚期糖基化终末产物受体水平可能与膝关节骨关节炎病变的严重性和进展程度相关。     

瑞舒伐他汀通过抑制晚期糖基化终末产物受体改善晚期内皮祖细胞再内皮化功能

 目的: 研究C反应蛋白(CRP)对晚期内皮祖细胞的晚期糖基化终产物受体(RAGE)表达的影响,并探讨瑞舒伐他汀是否改善CRP诱导的晚期内皮祖细胞再内皮化功能。方法: Western blot检测RAGE蛋白表达情况,MTT检测细胞活力、Transwell小室检测迁移能力及黏附能力来观察瑞舒伐他汀对于CRP诱导的晚期内皮祖细胞再内皮化功能的影响。结果: 随着CRP刺激浓度增加,RAGE蛋白表达量逐渐增加;而瑞舒伐他汀预孵育后,RAGE表达量逐渐下降。瑞舒伐他汀对于CRP诱导后的晚期内皮祖细胞的细胞活性没有显著改变;而迁移能力和粘附能力均随着瑞舒伐他汀浓度逐渐增加而增加,其中10^-6 mol/L瑞舒伐他汀组与CRP对照组比较均显著增强(P<0.01)。结论: CRP上调晚期内皮祖细胞RAGE的表达,瑞舒伐他汀可通过抑制RAGE表达增强CRP诱导的晚期内皮祖细胞的迁移和粘附能力,从而改善其再内皮化功能。     

晚期糖基化终末产物通过氧化应激诱导大鼠软骨细胞损伤

目的:探讨晚期糖基化终末产物(advanced glycation end products,AGEs)能否通过氧化应激引起大鼠软骨细胞损伤。方法:原代培养SD大鼠软骨细胞,对细胞表型进行鉴定;应用CCK-8法检测软骨细胞生存率;DCFH-DA染色荧光显微镜下检测胞内活性氧簇(reactive oxygen species,ROS)的水平;Hoechst 33342核染色法及Annexin V-FITC/PI流式细胞法测定软骨细胞的凋亡率;RT-PCR法检测软骨细胞中Bax、Bcl-2、caspase-3、MMP3、MMP13和COL2的mRNA水平;Western blotting法检测软骨细胞中cleaved caspase-3、MMP3、MMP13和COL2的蛋白水平。结果:与对照组相比,AGEs可显著上调胞内ROS水平(P0.05),但经抗氧化剂N-乙酰半胱氨酸(NAC)抑制后ROS的生成明显减少(P0.05);另外,NAC可抑制AGEs引起的软骨细胞凋亡相关分子Bax/Bcl-2和caspase-3水平的上调,并减少MMP3和MMP13表达及COL2的丢失(P0.05)。结论:AGEs可通过氧化应激诱导大鼠软骨细胞损伤。     

糖基化终末产物对人牙周膜干细胞生物学特性的影响

目的探讨糖基化终末产物(advanced glycation end products,AGEs)对人牙周膜干细胞(human periodontal ligament stem cells,HPDLSCs)生物学特性的影响研究。方法 HPDLSCs培养、提纯以及鉴定;检测不同质量浓度AGEs(50、100、200μg/ml)下HPDLSCs增殖能力、克隆能力、成骨分化能力。Real-time PCR检测不同质量浓度AGEs对HPDLSCs白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子(TNF-α)m RNA表达的影响。结果 MTT结果显示,与正常组比较,不同质量浓度AGEs均抑制HPDLSCs的增殖,且200μg/ml AGEs抑制最明显。克隆结果显示,与正常组比较,不同质量浓度AGEs均抑制HPDLSCs的自我更新及克隆能力,且200μg/ml AGEs抑制最明显。成骨分化能力结果显示,与正常组比较,不同质量浓度AGEs均抑制HPDLSCs的成骨能力,且200μg/ml AGEs抑制最明显。RT-PCR结果显示,与正常组比较,不同质量浓度AGEs均促进IL-1β、IL-6和TNF-αm RNA的表达,且随着质量浓度的增加,炎性因子的表达增加。结论 AGEs成浓度依赖性抑制HPDLSCs的增殖能力、自我更新能力、克隆能力和成骨分化能力,同时刺激炎性因子的表达。因此,牙周膜干细胞治疗糖尿病伴牙周病导致的牙周组织损伤要考虑糖基化终末产物的影响。     

维生素D3的免疫调节作用

维生素D3及其衍生物是维系体内钙磷平衡最重要的调节因子，近期随着研究的深入，已逐渐发现除上述功能外，它还具有重要的免疫调节作用，在免疫细胞的转化、信号的转导等方面均发现其存在独特的功能，对其免疫学功能方面的探讨已成为研究的热点之一。     

Plasma Levels of Soluble Receptor for Advanced Glycation End Products and Coronary Atherosclerosis: Possible Correlation with Clinical Presentation

Receptor for Advanced Glycation End-products (RAGE) is a multi-ligand receptor ubiquitous present on epithelial, neuronal, vascular and inflammatory cells, usually expressed at low levels in homeostasis and to increased degrees at sites of stress or injury. The aim of the present study was to evaluate sRAGE plasma levels in patients with Acute Coronary Syndrome (ACS) and to assess its diagnostic efficacy in identification of patients with acute events. Plasma levels of sRAGE were determined in 860 patients with Coronary Artery Disease (CAD): 530 patients presented stable angina and 330 were observed during acute ischemic event (147 with unstable angina and 183 with myocardial infarction). sRAGE plasma levels were significantly lower in patients with ACS than in patients with stable angina: [median 584 pg/mL (IQR: 266–851 pg/mL) in MI patients, median 769 pg/mL (IQR: 394–987 pg/mL) in patients with unstable angina, median 834 pg/mL (IQR 630–1005 pg/mL) in patients with stable angina; P < 0.001]. sRAGE levels did not differ among ACS patients stratified by the extent of coronary artery disease. In conclusion, this study confirm the role of sRAGE in activation and progression of inflammatory process and suggests the possibility that sRAGE can be considered an indicator of destabilization of vulnerable plaque.     

Serum 25-Hydroxy Vitamin D Levels and Association of Vitamin D Receptor Gene Polymorphisms in Vitiligo

BackgroundThe role of vitamin D deficiency and vitamin D receptor (VDR) gene polymorphisms has been established in many autoimmune diseases, including vitiligo, but the result is still controversial.ObjectivesThe aim of this study was to investigate the serum vitamin D levels in vitiligo patients and to compare the association of VDR gene polymorphisms in vitiligo patients and healthy controls.MethodsWe collected the data of age, sex, serum 25-hydroxy vitamin D (25[OH]D) level, thyroid autoantibodies, disease duration, types of vitiligo, family history and the affected body surface area of vitiligo from 172 patients. And we analyzed the VDR gene polymorphisms in 130 vitiligo and 453 age-sex-matched control subjects.ResultsThe mean serum level of 25(OH)D in 172 vitiligo patients was 18.75 ± 0.60 ng/mL, which had no significant difference with a mean serum value of 25(OH)D in the Korean population. However, there were significant differences according to the duration of the disease and family history. Also, there were no significant differences in the genotypic and allelic distributions of 37 examined SNPs of VDR gene between vitiligo patients and healthy controls.ConclusionSerum level of 25(OH)D in vitiligo patients was not significantly different from the mean serum value of the Korean population. Also, there were no significant differences in the genotypic distributions of VDR gene between vitiligo patients and healthy controls.     

The Emerging Role of the Receptor for Advanced Glycation End Products on Innate Immunity

Cells from innate immune system are activated by the engagement of germ-line encoded pattern-recognition receptors (PRRs) in response to the microbial insult. These receptors are able to recognize either the presence of highly conserved microbial components called pathogen-associated molecular patterns or endogenous danger-associated molecular patterns. These danger signals are recognized by different types of (PRRs), including the receptor for advanced glycation end products. This new PRR share both ligands and intracellular signaling with Toll-like receptors and thus may cooperate with each other as essential partners to strength inflammatory response. This review summarizes recent advances in understanding the promiscuity of this receptor as well as its role in the context of innate immunity by triggering an inflammatory response when innate immune cells detect infection or tissue injury.     

Vitamin D Repletion in Korean Postmenopausal Women with Osteoporosis

PurposeUp to 71% of South Korean postmenopausal women have vitamin D deficiency {serum 25-hydroxyvitamin D [25(OH) D] level <50 nmol/L}. Data on vitamin D supplementation was collected during the screening phase of an efficacy/safety study of denosumab in Korean postmenopausal women with osteoporosis. This report describes the effect of vitamin D supplementation on repletion to 25(OH)D levels ≥50 nmol/L in Korean postmenopausal women with osteoporosis.ResultsOf 371 subjects screened, 191 (52%) required vitamin D supplementation, and 88% (168 of 191) were successfully repleted. More than half of the subjects (58%) who were successfully repleted received doses of 2000 IU daily. The mean time to successful repletion was 31 days (standard deviation 8.4 days; range 11–48 days).ConclusionSupplementation with daily median doses of 2000 IU vitamin D successfully repleted 88% of Korean postmenopausal women with osteoporosis within 48 days to a serum vitamin D level of 50 nmol/L.     

Survey of the Distribution of a Newly Characterized Receptor for Advanced Glycation End Products in Tissues

Advanced glycation end products (AGEs), the final products of nonenzymatic glycation and oxidation of proteins, are found in the plasma and accumulate in the tissues during aging and at an accelerated rate in diabetes. A novel integral membrane protein, termed receptor for AGE (RAGE), forms a central part of the cell surface binding site for AGEs. Using monospecific, polyclonal antibody raised to human recombinant and bovine RAGE, immunostaining of bovine tissues showed RAGE in the vasculature, endothelium, and smooth muscle cells and in mononuclear cells in the tissues. Consistent with these data, RAGE antigen and mRNA were identified in cultured bovine endothelium, vascular smooth muscle, and monocyte-derived macrophages. RAGE antigen was also visualized in bovine cardiac myocytes as well as in cultures of neonatal rat cardiac myocytes and in neural tissue where motor neurons, peripheral nerves, and a population of cortical neurons were positive. In situ hybridization confirmed the presence of RAGE mRNA in the tissues, and studies with rat PC12 pheochromocytes indicated that they provide a neuronal-related cell culture model for examining RAGE expression. Pathological studies of human atherosclerotic plaques showed infiltration of RAGE-expressing cells in the expanded intima. These results indicate that RAGE is present in multiple tissues and suggest the potential relevance of AGE-RAGE interactions for modulating properties of the vasculature as well as neural and cardiac function, prominent areas of involvement in diabetes and in the normal aging process.     

Glycation Endproducts, Soluble Receptor for Advanced Glycation Endproducts and Cytokines in Diabetic and Non-diabetic Pregnancies

Problem  Cytokines, advanced glycation end products (AGEs), and their receptor RAGE have been recently suggested to play a role in human pregnancy. In this study, we sought to determine the alterations of plasma AGEs, soluble RAGE (sRAGE), and proinflammatory cytokines in normal pregnancies and those complicated with type 1 diabetes mellitus.
Method of study  These parameters were measured in samples from healthy non-pregnant (C), diabetic non-pregnant (D), healthy pregnant (HP), and pregnant diabetic (DP) women.
Results  In the first trimester, DP showed lower sRAGE and higher AGEs compared to HP. In the DP group, significant negative correlations were seen between TNF-α and lipopolysaccharide (LPS)-stimulated ΙL-6 in the first trimester and sRAGE in the third trimester. LPS-stimulated IL-12 was positively correlated with levels of AGEs in the third trimester.
Conclusion  We detected several differences in the levels of AGEs, sRAGE, and proinflammatory cytokines between euglycemic and diabetic pregnancies.     

Nutritional Status of Vitamin D and the Effect of Vitamin D Supplementation in Korean Breast-fed Infants

We investigated the vitamin D status and the effect of vitamin D supplementation in Korean breast-fed infants. The healthy term newborns were divided into 3 groups; A, formula-fed; B, breast-fed only; S, breast-fed with vitamin D supplementation. We measured serum concentrations of vitamin D (25OHD3), calcium (Ca), phosphorus (P), alkaline phosphatase (AP), intact parathyroid hormone (iPTH) and bone mineral density (BMD) at 6 and 12 months of age. Using questionnaires, average duration of sun-light exposure and dietary intake of vitamin D, Ca and P were obtained. At 6 and 12 months of age, 25OHD3 was significantly higher in group S than in group B (P<0.001). iPTH was significantly lower in group S than in group B at 6 months (P=0.001), but did not differ at 12 months. Regardless of vitamin D supplementation, BMD was lower in group B and S than in group A (P<0.05). Total intake of vitamin D differed among 3 groups (P<0.001, A>S>B), but total intake of Ca and P were higher in group A than in group B and S (P<0.001). In conclusion, breast-fed infants show lower vitamin D status and bone mineralization than formula-fed infants. Vitamin D supplementation (200 IU/day) in breast-fed infants increases serum 25-OH vitamin D₃, but not bone mineral density.     

Association of Polymorphisms in the Vitamin D Receptor Promoter with Idiopathic Short Stature

The genetic alterations of vitamin D receptor (VDR) are related with the growth of long bone. There were a lot of reports regarding an association of polymorphisms in the VDR promoter with many disorders, but not with idiopathic short stature (ISS). We investigated the association of them with ISS. A total of 50 subjects, including 29 ISS patients and 21 healthy controls with their heights within the normal range was recruited. We selected two single nucleotide polymorphisms (SNPs) from VDR promoter (rs11568820 at the Cdx-2 binding site upstream of exon 1e and rs4516035 at -1012 upstream of exon 1a) as candidates, respectively. In genotype analysis, the frequency of A/A genotype at the Cdx-2 binding site locus (rs11568820) upstream of exon 1e of VDR was decreased to 6.9% in ISS patients (28.6% in controls) (P = 0.027). The genetic variation at the Cdx-2 binding site of VDR promoter can be a contributing factor of growth of height.