Insulin Prevents Latent Skin Lesions by Inhibiting the Generation of Advanced Glycation End Products in Streptozotocin-Induced Diabetic Rats

The preventive effect of insulin on latent skin lesions in streptozotocin-induced diabetic rats was investigated. Diabetes was induced in 72 male Sprague–Dawley rats, with 36 rats serving as the control group. Half of the diabetic rats were treated with insulin, and the other half were injected with vehicle. Skin tissues were collected 4, 8, and 12 weeks after the initiation of insulin therapy for measurement of glucose, collagen-related fluorescence and advanced glycation end product (AGE) expression, and histological observation. The diabetic rats exhibited changes in skin tissue, including a decrease in thickness, disappearance of the multilayer epithelium structure, degeneration of collagen fibers, and an increase in the infiltration of inflammatory cells, in addition to a significant increase in blood glucose and AGE expression. These effects were greatly ameliorated by insulin therapy. Insulin therapy in early-stage diabetes mellitus prevents potential skin lesions, possibly by inhibiting AGE formation and inflammatory reactions following glycemic control. Xiangfang Chen and Weidong Lin contributed equally to this work.     

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.     

The Role of High Mobility Group Box 1 in Innate Immunity

With growing accounts of inflammatory diseases such as sepsis, greater understanding the immune system and the mechanisms of cellular immunity have become primary objectives in immunology studies. High mobility group box 1 (HMGB1) is a ubiquitous nuclear protein that is implicated in various aspects of the innate immune system as a damage-associated molecular pattern molecule and a late mediator of inflammation, as well as in principal cellular processes, such as autophagy and apoptosis. HMGB1 functions in the nucleus as a DNA chaperone; however, it exhibits cytokine-like activity when secreted by injurious or infectious stimuli. Extracellular HMGB1 acts through specific receptors to promote activation of the NF-κB signaling pathway, leading to production of cytokines and chemokines. These findings further implicate HMGB1 in lethal inflammatory diseases as a crucial regulator of inflammatory, injurious, and infectious responses. In this paper, we summarize the role of HMGB1 in inflammatory and non-inflammatory states and assess potential therapeutic approaches targeting HMGB1 in inflammatory diseases.     

Advanced glycation end-products and receptor for advanced glycation end-products expression in patients with idiopathic pulmonary fibrosis and NSIP

Advanced glycation end products (AGEs) are associated with the pathogenesis of various diseases. AGEs induce excess accumulation of extracellular matrix and expression of profibrotic cytokines. In addition, studies on receptor for advanced glycation end products (RAGE) have shown that the ligand-RAGE interaction activates several intracellular signaling cascades associated with several fibrotic diseases. We investigated the expression of AGEs and RAGE in samples from patients with idiopathic pulmonary fibrosis (IPF) and non-specific interstitial pneumonia (NSIP). Lung tissues and plasma samples from patients with IPF (n=10), NSIP (n=10), and control subjects (n=10) were obtained. Expression of AGEs and RAGE was determined by immunofluorescence assay of lung tissue. Circulating AGEs were measured by Western blot and enzyme-linked immunosorbent assay. Lungs with IPF showed strong expression for both AGEs and RAGE compared to that in NSIP and controls. However, no difference in AGE or RAGE expression was observed in lungs with NSIP compared to that in the controls. Levels of circulating AGEs also increased significantly in lungs of patients with IPF compared to those with NSIP and normal control. Increased AGE-RAGE interaction may play an important role in the pathogenesis of IPF.     

Elevated IgG and IgM Autoantibodies to Advanced Glycation End Products of Vascular Elastin in Hypertensive Patients with Type 2 Diabetes: Relevance to Disease Initiation and Progression

The increased glycation of elastin is an important factor in vascular changes in diabetes. Using the ELISA method, we determined serum levels of IgM and IgG autoantibodies to advanced glycation end products of vascular elastin (anti-AGE EL IgM and anti-AGE EL IgG) in 59 hypertensive patients with type 2 diabetes (T2D) and 20 healthy controls. Serum levels of matrix metalloproteinases-2 and -9 (MMP-2 and MMP-9) and the C-reactive protein (CRP) were also determined. The levels of anti-AGE EL IgM antibodies in the T2D group were similar to those in the control group, while those of anti-AGE EL IgG antibodies were significantly higher (p = 0.017). Significant positive correlations were found between the levels of anti-AGE EL IgM antibodies and MMP-2 (r = 0.322; p = 0.013) and between the levels of anti-AGE EL IgG antibodies and CRP (r = 0.265; p = 0.042). Our study showed that elevated anti-AGE EL IgG antibody levels may be an indicator of the enhanced AGE-modification and inflammatory-mediated destruction of vascular elastin in hypertensive patients with T2D. Anti-AGE EL IgM antibodies may reflect changes in vascular MMP-2 activity, and their elevated levels may be a sign of early vascular damage.     

High mobility group box 1 (HMGB1) levels in the placenta and in serum in preeclampsia

Citation
Wang B, Koga K, Osuga Y, Hirata T, Saito A, Yoshino O, Hirota Y, Harada M, Takemura Y, Fujii T, Taketani Y. High mobility group Box 1 (HMGB1) levels in the placenta and in serum in preeclampsia. Am J Reprod Immunol 2011; 66: 143–148 Problem Preeclampsia is a pregnancy disorder characterized by systemic inflammation. High mobility group box 1 (HMGB1) is a molecule known to act as a ‘danger signal’ by participating in various inflammatory processes, but data in regard to preeclampsia are sparse. The aim of this study was to analyze placental and serum HMGB1 levels in normal pregnancy and preeclampsia. Method of study Sera were collected from women with preeclampsia soon after the manifestation of the disease and before commencing any medication. Placental samples were collected immediately after delivery. Expressed isoforms of HMGB1 (28‐ and 30‐kDa) in the placenta were evaluated by Western blot analysis. Serum HMGB1 concentrations were measured using enzyme‐linked immunosorbent assays (ELISA). Results Two isoforms of HMGB1 are expressed by the human placenta. The 28‐ and 30‐kDa HMGB1 isoforms were expressed highly in preeclamptic placental tissue; however, compared with normotensive control tissue, differences in detected expression levels did not reach statistical significance. No significant difference was observed in serum HMGB1 levels between control and preeclampsia. Conclusion Inflammation provoked by HMGB1 is likely to be involved in the proinflammatory process in preeclamptic placenta. Further studies are needed to elucidate the precise role of HMGB1 in preeclampsia.     

Pitavastatin attenuates AGEs-induced mitophagy via inhibition of ROS generation in the mitochondria of cardiomyocytes

This study aimed to investigate whether pitavastatin protected against injury induced by advanced glycation end products products (AGEs) in neonatal rat cardiomyocytes, and to examine the underlying mechanisms. Cardiomyocytes of neonatal rats were incubated for 48 hours with AGEs (100 mg/mL), receptor for advanced glycation end products (RAGE), antibody (1 mg/mL) and pitavastatin (600 ng/mL). The levels of p62 and beclin1 were determined by Western blotting. Mitochondrial membrane potential (DYm) and the generation of reactive oxygen species (ROS) were measured through the JC-1 and DCFH-DA. In the AGEs group, the expression of beclin1 was remarkably increased compared to the control group, while the expression of p62 was significantly decreased. AGEs also markedly decreased DYm and significantly increased ROS compared with the control group. After treatment with RAGE antibody or pitavastatin, the level of beclin1 was markedly decreased compared with the AGEs group, but the level of p62 was remarkably increased. In the AGEs + RAGE antibody group and AGEs + pitavastatin group, DYm was significantly increased and ROS was remarkably decreased compared with the AGEs group. In conclusion, AGEs-RAGE may induce autophagy of cardiomyocytes by generation of ROS and pitavastatin could protect against AGEs-induced injury against cardiomyocytes.     

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     

内源性分泌型糖基化终末产物受体及糖基化白蛋白与2型糖尿病合并冠心病的关系

目的:探讨血清内源性分泌型糖基化终末产物受体(esRAGE)、糖基化白蛋白(GA)水平与糖尿病合并冠心病及冠脉病变严重程度的关系。方法:入选2型糖尿病患者(冠状动脉正常)302例(2型糖尿病组)及2型糖尿病合并冠心病(CAD)患者357例(2型糖尿病并CAD组)。测定并比较二组血清esRAGE、GA水平并分析其与CAD及冠脉病变严重程度的关系。结果:2型糖尿病并CAD组血清GA水平(21.28±4.31%)及GA/esRAGE比值(1.21±0.68)明显高于2型糖尿病组(19.41±3.62%及0.78±0.46,均P<0.01),esRAGE水平(0.22±0.10ng/ml)明显低于2型糖尿病组(0.31±0.14ng/ml,P<0.01);冠脉3支病变组血清esRAGE水平低于1及2支病变组(均P<0.01);冠脉3支病变组血清GA水平、GA/esRAGE比值高于1及2支病变组(均P<0.01)。血清GA水平及GA/esRAGE比值与冠脉病变严重程度呈正相关,esRAGE水平与冠脉病变严重程度呈负相关。结论:血清高GA水平及低esRAGE水平与2型糖尿病并CAD及冠脉病变严重程度相关。糖基化负荷增加伴保护因素削弱,是2型糖尿病患者合并CAD的易感因素,GA/esRAGE比值是反映糖基化负荷与保护因素之间不平衡的简易而有效的指标。     

糖尿病大鼠血管糖基化终产物含量与其受体的ICAM—1表达的关系

探讨糖尿病大鼠血管组织糖基化终产物（AGEs)含量与其受体（RAGE）和细胞间粘附因子－1（ICAM－1）表达的关系。复制糖尿病大鼠模型,采用荧光法、RT－PCR及原位杂交方法检测主动脉及心肌组织的AGEs含量以及RAGE和ICAM－1基因的表达。发现糖尿病大鼠主动脉和心肌组织AGEs含量升高（P＜0．01）;RAGE和ICAM－1基因表达增强（P＜0．05－0．05）;AGEs含量与RAGE及ICAM－1呈明显正相关（P＜0．01）;氨基胍治疗可缓解上述指标的变化。提示 AGEs可诱导RAGE和ICAM－1的表达。推测AGEs-RAGE相互作用是引起糖尿病血管内皮细胞功能紊乱和损伤的关键环节。     

维生素D_3对缺乏维生素D的多囊卵巢综合征患者晚期糖基化终末产物受体的影响

目的研究维生素D3摄入对缺乏维生素D的多囊卵巢综合征(PCOS)患者血清AMH和sRAGE的影响。方法 54例患者分为25例缺乏维生素D合并PCOS的观察组和29例仅缺乏维生素D的对照组,给予口服8周维生素D3,检测口服前和口服8周后血清25-羟基维生素D(25 OH-D),AMH和sRAGE浓度。结果观察组和对照组摄入维生素D3后血清25 OH-D升高,且观察组血清sRAGE水平上升,AMH水平下降。结论缺乏维生素D合并PCOS患者摄入维生素D3可以通过增加sRAGE抑制AGEs的活性起到保护性作用。此外,维生素D3促进观察组患者血清AMH水平降低,改善卵泡生长发育环境。     

Safety Analysis of the Diaphragm in Combination with Lubricant or Acidifying Microbicide Gels: Effects on Markers of Inflammation and Innate Immunity in Cervicovaginal Fluid

Objective  Diaphragms are being considered for use with vaginal microbicide gels to provide enhanced protection against sexually transmitted pathogens. The purpose of this study was to determine whether use of a diaphragm with microbicide or placebo gel causes cervicovaginal inflammation or perturbations in cervicovaginal immune defense.
Method of study  Eighty-one non-pregnant women were randomized into three groups and instructed to use Milex^® (CooperSurgical, Inc., Trumbull, CT, USA)diaphragms overnight for 14 days in combination with one of the two acid-buffering microbicide gels [ACIDFORM^™ (Instead Inc., La Jolla, CA, USA) or BufferGel^™ (BG; ReProtect Inc., Baltimore, Maryland)] or placebo gel (K-Y Jelly^®; Personal Products Inc., Raritan, NJ, USA). Cervicovaginal lavages (CVLs) were performed prior to study entry and on days 8 and 16. Nine soluble mediators of vaginal inflammation or immune defense were measured in CVLs by Bio-Plex or ELISA.
Results  Use of diaphragms with placebo or microbicide gel was not associated with increased levels of inflammation markers. Concentrations of secretory leukocyte protease inhibitor (SLPI) were markedly reduced in the BG group.   Conclusion 

Daily use of a diaphragm with placebo or acidifying microbicide gel did not cause cervicovaginal inflammation. However, diaphragm/BG use was associated with markedly reduced levels of SLPI, an important mediator of innate immune defense. Further studies are warranted to establish the safety of diaphragm/microbicide gel combinations.     

Effects of bone marrow MSCs transfected with sRAGE on the intervention of HMGB1 induced immuno-inflammatory reaction

Background: High mobility group box chromosomal protein 1 (HMGB1) is an important proinflammatory molecule in many inflammatory disorders, but little is known about its role in acute liver failure (ALF). In this study, we determined the plasma and hepatic tissue levels of HMGB1 in a d-galactosamine-induced rat ALF model and investigated the effect of soluble receptor for advanced glycation end products (sRAGE) on ALF successfully. Methods: Male Sprague-Dawley rats were divided into five groups randomly. Group A (Control group, n=20) received administrated saline via peritoneal cavity. Group B (ALF group, n=20) induced by d-galactosamine (0.6 g/kg) via peritoneal cavity. Group C (HMGB1 group, n=20) were treated with HMGB1 recombination protein (200 μg/kg) via penile vein after ALF model induced. Group D (sRAGE group, n=20) received administrated sRAGE recombination protein (400 μg/kg) via penile vein after ALF model induced. Group E (sRAGE-MSC group, n=20) received 3×10⁶ MSC transplantation which could maintain a stable expression of sRAGE via penile vein after ALF model induced. Liver function, level of cytokines and liver pathological changes were measured. Results: We determined that the plasma levels and hepatic tissue levels of HMGB1 were significant increased in ALF model (P<0.05). SRAGE group and sRAGE-MSC group could significantly prolong ALF rat survival time, as well as improve its liver functions, inflammatory cytokines level and hepatocytes necrosis. Conclusion: SRAGE as a ligand decoy has illustrated largely beneficial effects on reducing immuno-inflammatory response, which holds promise for the identification of potential therapeutic targets and/or biomarkers of RAGE activity in ALF.     

血清PCT、RAGE、sTREM-1表达水平与重症肺炎患者病情严重程度及预后的关系

目的探究血清降钙素原(PCT)、晚期糖化终产物受体(RAGE)、可溶性髓样细胞触发受体-1(sTREM-1)水平与重症肺炎患者病情严重程度及预后的关系。方法选择2016年3月至2019年2月我院呼吸内科收治的98例重症肺炎患者及100例普通肺炎作为研究对象,分别纳入重症肺炎组及普通肺炎组。根据是否合并多器官功能障碍综合征(MODS)将重症肺炎组患者分为单纯重症肺炎组及重症肺炎合并MODS组两个亚组;根据28d疾病转归情况分为存活组及死亡组。比较各组患者血清学指标差异,分析其与急性生理慢性健康评分(APACHEII)的相关性,并绘制ROC曲线分析其预测预后的价值。结果单纯重症肺炎组、重症肺炎合并MODS组患者血清PCT、RAGE、sTREM-1、C反应蛋白(CRP)水平显著高于普通肺炎组(P<0.05);重症肺炎合并MODS组患者各血清学指标及APACHEII评分显著高于单纯重症肺炎组患者(P<0.05);血清PCT、RAGE、sTREM-1水平与APACHEII呈正相关关系(P<0.05);入组重症肺炎组患者均获得治疗并随访,28d内死亡的患者39例,存活患者59例,死亡组患者血清PCT、RAGE、sTREM-1、CRP水平显著高于存活组患者(P<0.05);血清PCT、RAGE、sTREM-1、CRP预测预后的曲线下面积分别为0.713、0.776、0.809、0.701,其中sTREM-1曲线下面积最大,截点值为50.61 ng/L;4种指标联合预测的曲线下面积为0.901。结论血清PCT、RAGE、sTREM-1表达水平与重症肺炎患者病情严重程度相关,其水平高低可作为评估患者病情、预测预后的参考指标。     

可溶性糖基化终末产物受体抑制动物缺血再灌注导致的心功能障碍及心肌细胞凋亡

目的 建立动物心脏缺血再灌注模型,探讨可溶性糖基化终末产物受体（sRAGE）对缺血再灌注诱导的心功能及心肌细胞凋亡的作用。 方法 复制C57BL/6J小鼠心脏缺血再灌注模型,利用超声检测心功能;通过TUNEL染色及Caspase-3活性检测,评价心肌细胞凋亡的程度。 结果 与sham组比较,I/R组左室射血分数降低［sham组为（72.4±2.1）%,I/R组为（30.9±3.2）%,P<0.05］,短轴缩短率降低［sham组为(40.7±1.6)%, I/R组为（15.1±2.0）% , P<0.05］,TUNEL阳性心肌细胞数目增加［sham组为(1.0±0.2)%, I/R组为（20.0±1.6）% , P<0.05］, Caspase-3活性升高［（sham组(1.00±0.2）%比I/R组（2.64±0.4）%,P<0.05）。与I/R组相比较,sRAGE预处理能够明显升高左室射血分数［（46.5±2.0）% P<0.05］,增加短轴缩短率［（23.0±1.1）%,P<0.05］,同时降低TUNEL阳性心肌细胞数目［（9.2%±1.0）% P<0.05］,和Caspase-3活性［（1.94%±0.1）% P<0.05］。 结论 sRAGE能够明显改善缺血再灌注诱导的心功能降低,并抑制心肌细胞的凋亡。     

Effects of air pollutants on innate immunity: the role of Toll-like receptors and nucleotide-binding oligomerization domain-like receptors

Interactions between exposure to ambient air pollutants and respiratory pathogens have been shown to modify respiratory immune responses. Emerging data suggest key roles for Toll-like receptor (TLR) and nucleotide-binding oligomerization domain-like receptor (NLR) signaling in pathogen-induced immune responses. Similarly, immune responses elicited by exposure to air pollutants are mediated by specific TLR- and NLR-dependent mechanisms. This review article will summarize current knowledge about how air pollutants modify TLR- and NLR-dependent signaling and host defense responses in the lung.     

Impact of hyperglycemia and acute pancreatitis on the receptor for advanced glycation endproducts

Since hyperglycemia aggravates acute pancreatitis and also activates the receptor for advanced glycation endproducts (RAGE) in other organs, we explored if RAGE is expressed in the pancreas and if its expression is regulated during acute pancreatitis and hyperglycemia. Acute pancreatitis was induced by cerulein in untreated and streptozotocin treated diabetic mice. Expression of RAGE was analyzed by Western blot and immunohistochemistry. To evaluate signal transduction the phosphorylation of ERK1/ERK2 was assessed by Western blot and the progression of acute pancreatitis was monitored by evaluation of lipase activity and the pancreas wet to dry weight ratio. RAGE is mainly expressed by acinar as well as interstitial cells in the pancreas. During acute pancreatitis infiltrating inflammatory cells also express RAGE. Using two distinct anti-RAGE antibodies six RAGE proteins with diverse molecular weight are detected in the pancreas, whereas just three distinct RAGE proteins are detected in the lung. Hyperglycemia, which aggravates acute pancreatitis, significantly reduces the production of two RAGE proteins in the inflamed pancreas.