氨甲酰促红细胞生成素的神经保护作用及机制的研究进展

氨甲酰促红细胞生成素(Carbamylated erythropoietin,CEPO)是促红细胞生成素(Erythropoietin,EPO)的一种衍生物,与EPO一样具有神经保护作用,但是没有其造血功能。已有大量实验研究证实了CEPO的神经保护作用,并有最新研究阐述了EPO和CEPO具有不同的信号转导通路。本文主要介绍了CEPO的减轻神经细胞水肿、促进神经细胞分化、改善神经功能恢复等神经保护作用及CEPO可能通过激活CEPO受体、CD131、神经胶质细胞源性的神经营养因子(Glial cell line derived neurotrophic factor,GDNF)、蛋白激酶B(Protein kinase B,Akt)等机制发挥其神经保护作用。     

促红细胞生成素通过提高Sca-1+干细胞的功能参与小鼠心肌梗死的修复(英文)

心肌梗死(myocardial infarction, MI)是目前全球主要的死亡病因之一。随着临床治疗水平的提高,MI急性期的死亡率已显著下降,但其对心肌重构及心功能的长远影响仍无法有效防治。促红细胞生成素(erythropoietin, EPO)是一种糖蛋白细胞因子,具有促进造血、抗凋亡和促血管生成的作用。研究表明EPO在心脏缺血损伤、心力衰竭等心血管疾病中发挥心肌保护作用,机制与促进心脏祖细胞活化有关。本研究旨在探讨EPO是否可通过增强Sca-1⁺干细胞的活性促进MI的修复。通过直接注射法将达贝泊汀-α (darbepoetin alpha,一种长效EPO类似物,EPO_anlg)注射到成年小鼠MI的交界区,观测MI面积、心脏重构及功能、心肌细胞凋亡及微血管密度变化。用磁性分选技术从新生和成年小鼠心脏中分离Lin^-Sca-1⁺干细胞,分别用于克隆形成能力及EPO效应的测定。结果显示,和单纯的MI组相比,在体应用EPOanlg可显著降低MI面积、心肌细胞凋亡率,减轻左室腔的扩张,同时提高心功能、增...     

促红细胞生成素和受体在前列腺癌组织中共同过表达的研究

目的:探讨促红细胞生成素(EPO)和受体(EPOR)在前列腺癌(PCa)组织中的表达,并进一步阐述EPO和EPOR在前列腺癌发生发展中所起的作用。方法:应用免疫组化SP法检测30例前列腺癌根治术组织标本中癌与增生(BPH)组织的EPO和EPOR表达及30例正常前列腺组织(NP)中的EPO和EPOR表达。前列腺癌分级采用Gleason评分。半定量EPO和EPOR评分分析免疫组化结果。同时根据细胞染色强度区分为过表达和正常表达。统计学分析采用配对样本比较Wilcoxon的秩和检验及线形回归分析。结果:大部分前列腺癌均可见EPO和EPOR同时过表达,但是前列腺增生组织只有EPO过表达;正常前列腺组织没有EPO和EPOR过表达。前列腺癌和良性前列腺增生的EPO免疫组化评分中位数为2.38和0.93(P<0.01);前列腺癌和良性前列腺增生的EPOR免疫组化评分中位数为2.50和0.68(P<0.01)。前列腺增生和前列腺癌的EPO和EPOR表达密切相关,但是前列腺癌的Gleason评分和EPO以及EPOR评分没有相关性(P值均>0.05)。结论:EPO和EPOR同时过表达促进前列腺癌发生发展,但是相对于EPO的过表达,EPOR过表达是前列腺癌发生更为重要的早期事件;前列腺癌组织中EPO和EPOR表达差异,提示除了缺氧外,可能还有其它机制参与EPOR的过表达。     

红细胞生成素受体研究进展

红细胞生成素受体是促红细胞生成素的作用受体 ,属于细胞因子超家族的成员。近年来 ,由于其克隆表达技术的应用使人们在对造血机制、EPO的信号转导机制 ,及利用其受体筛选 EPO类似物方面的研究有了新的进展。本文综合近年来有关文献对 EPO受体的研究作一概括性介绍。     

促红细胞生成素治疗慢性心力衰竭156例临床观察

目的:观察EPO对慢性充血性心力衰竭(CHF)治疗效果。方法:选择CHF患者212例,随机分为非EPO治疗组(56例)和EPO治疗组(156例)。其中非EPO治疗组采用常规抗心衰治疗,EPO治疗组接受常规抗心衰治疗和EPO治疗,直至临床观察结束。治疗后观察心功能指标改变。结果:156例心衰患者经过EPO治疗后,左室射血分数,每搏输出量,每分输出量,心指数均较非EPO治疗对照组患者明显改善(P<0.05),其中尤以左室射血分数改善最为明显(P<0.01)。156例EPO治疗组患者中116例心衰伴贫血患者心功能各项指标的改善较40例心衰不伴贫血患者更为明显,具有显著统计学意义(P<0.01)。结论:EPO对CHF患者心功能的改善主要是因为EPO的促红细胞生成作用。EPO对于慢性心功能不全有独立于促红细胞生成以外的治疗作用。     

促红细胞生成素(EPO)

一、产品概述 促红细胞生成素(Erythropoietin,EPO)主要是在肾脏中产生的一种造血激素,是具有166个氨基酸残基,分子量为35000的糖蛋白。 EPO对原红细胞集落生成细胞CFU-E或其早幼阶段的BFU-E起作用,具有促进向红细胞前体细胞--网状红细胞,原红细胞的分化,并生成红细胞的作用。     

缺氧培养对大鼠神经干细胞体外增殖影响及其机制的研究

目的：研究应用缺氧对体外培养的大鼠神经干细胞增殖的影响。方法：将细胞分为4小时缺氧组、12小时缺氧组、促红细胞生成素（EPO）中和抗体组、IgG组以及对照组．测定大鼠神经干细胞经缺氧培养后的各组细胞克隆形成率以及EPO的表达变化。结果：单细胞培养条件下,与对照组相比,4小时缺氧组和IgG组克隆形成率明显增高;中和抗体组无明显变化;12小时组克隆形成率降低。但无统计学意义。缺氧4小时后,EPO蛋白在预处理后即刻出现表迭,4h达高峰,8h仍有部分表达。结论：短时间缺氧可以促进神经干细胞增殖．长时间缺氧则作用相反。缺氧对NSCs增殖作用的影响可能是由EPO介导产生。     

促红细胞生成素对神经干细胞缺氧性损伤保护作用的实验研究

目的观察外源性EPO对神经干细胞缺氧性损伤的保护作用,为缺氧缺血性脑损伤的治疗提供新思路。方法从孕11.5d（E11.5d）大鼠获得神经干细胞,经无血清培养基悬浮培养并传代,对所获细胞的自我增殖、自我更新及其多分化潜能进行检测。取传3代神经干细胞中添加不同剂量的EPO,在5%O2培养箱中培养120h。通过计数干细胞克隆形成率和MTT法检测神经干细胞的增殖情况。于含血清分化培养基中加入不同剂量的EPO,用NSE和GFAP免疫细胞化学染色观察神经干细胞的分化情况。采用AnnexinⅤ-FITC/PI染色,激光扫描共聚焦显微镜观察、检测细胞凋亡率。结果加入EPO后神经干细胞的克隆形成率和MTT检测的OD值显著增高,细胞凋亡率显著下降,NSE阳性细胞的比例明显升高,其作用随剂量增加而增大,50U/ml时作用最大。结论EPO对神经干细胞缺氧性损伤具有明显的保护作用,并可促进神经干细胞向神经元方向分化。EPO的这种作用随剂量增加而增大,50U/ml时达高峰。     

人红细胞生成素受体胞外区克隆及序列测定

人红细胞生成素受体 (h EPOR)是人红细胞生成素的作用配体 ,其胞外区是 h EPO的作用域 ,它的克隆、表达对两种分子的相互作用机制以及 EPO类似物 (新型造血药物 )的筛选都有十分重要的意义。以人胎肝为材料 ,通过对其总 RNA的提取 ,利用 RT- PCR方法扩增 h EPOR的胞外区基因和跨膜区基因及推导相应的氨基酸残基排列 ,结果与国外文献报道相比较从而检验其正确性。     

促红细胞生成素在脑缺血动物模型治疗中的研究进展

促红细胞生成素是一种促进红系造血前体细胞增殖、分化的细胞因子,主要作用为促进红细胞增殖,应用于临床各种贫血治疗。随着研究进展,学者发现促红细胞生成素为一种多功能营养因子及神经保护因子,具有调节中枢神经系统发育、神经营养及神经保护作用。脑缺血性卒中实验研究显示,促红细胞生成素可有效改善中枢神经系统疾病所致的神经功能缺损,本文主要概述促红细胞生成素在脑缺血性卒中动物模型的研究进展,及其发挥神经保护作用所经由的分子机制。相信随着实验研究进展,其在脑缺血性卒中临床治疗方面将拥有更广阔的前景。     

丁香苷抗炎镇痛作用及部分机制研究

研究丁香苷抗炎镇痛作用及部分机制。以阿司匹林作阳性对照药,观察丁香苷对二甲苯致小鼠耳廓肿胀、醋酸致小鼠毛细血管通透性增加、角叉菜胶致大鼠足趾肿胀、棉球致大鼠肉芽肿的抗炎作用;对小鼠热板试验、醋酸扭体试验的镇痛作用;同时测定角叉菜胶致大鼠炎足炎性渗出物中的PGE2、MDA和血清中的NO、SOD,初步探讨丁香苷抗炎镇痛的部分机制。结果表明,丁香苷对急慢性炎症反应有明显抑制作用,能明显降低角叉菜胶致炎足炎性渗出物中PGE2、MDA和血清中NO含量,明显增加血清中SOD的活性。因此,丁香苷具有较强的抗炎镇痛作用,其机制可能与抑制PGE2、NO等炎症介质生成、增强自由基清除能力有关。     

Erythropoietin augments the cytokine response to acute endotoxin-induced inflammation in humans

Recent studies have shown that erythropoietin (EPO) offers protection against ischemia, hemorrhagic shock and systemic inflammation in many tissues and it has been suggested that EPO has anti-inflammatory effects. With the aim of investigating the potential acute anti-inflammatory effects of EPO in a human in vivo model of acute systemic low-grade inflammation, we measured circulating inflammatory mediators after intravenous administration of Escherichia coli endotoxin (LPS) bolus injection (0.1 ng/kg of body weight) in young healthy male subjects. The subjects were divided into three groups receiving either (1) LPS alone, (2) EPO alone (15,000 IE of rHuEPO) or (3) EPO and LPS. Endotoxin administration alone induced a 3-, 12- and 5-fold increase in plasma concentrations of TNF-α, IL-6 and IL-10, respectively, 3 h after LPS challenge. When EPO was given prior to a bolus injection with endotoxin, the levels of TNF-α and IL-6 were enhanced by 5- and 40-fold, respectively, whereas the endotoxin-induced increase in IL-10 response was not influenced by EPO. In contrast to our hypothesis, we find that EPO augments the acute inflammatory effect.     

Non‐erythropoietic erythropoietin‐derived peptide protects mice from systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease, which results in various organ pathologies. However, current treatment towards SLE is suboptimal. Erythropoietin (EPO) has been shown to promote SLE recovery, but clinical application can be limited by its haematopoiesis‐stimulating effects. EPO‐derived helix‐B peptide (ARA290) is non‐erythrogenic but has been reported to retain the anti‐inflammatory and tissue‐protective functions of EPO. Therefore, here we investigated the effects and potential mechanisms of ARA290 on SLE. The administration of ARA290 to pristane‐induced SLE and MRL/lpr mice significantly suppressed the level of serum antinuclear autoantibodies (ANAs) and anti‐dsDNA autoantibodies, reduced the deposition of IgG and C3, and ameliorated the nephritis symptoms. Moreover, the serum concentrations of inflammatory cytokine IL‐6, MCP‐1 and TNF‐α in SLE mice were reduced by ARA290. Further, ARA290 decreased the number of apoptotic cells in kidney. In vitro experiment revealed that ARA290 inhibited the inflammatory activation of macrophages and promoted the phagocytotic function of macrophages to apoptotic cells. Finally, ARA290 did not induce haematopoiesis during treatment. In conclusion, ARA290 ameliorated SLE, which at least could be partly due to its anti‐inflammatory and apoptotic cell clearance promoting effects, without stimulating haematopoiesis, suggesting that ARA290 could be a hopeful candidate for SLE treatment.     

Post-translational tyrosine nitration of eosinophil granule toxins mediated by eosinophil peroxidase

Nitration of tyrosine residues has been observed during various acute and chronic inflammatory diseases. However, the mechanism of tyrosine nitration and the nature of the proteins that become tyrosine nitrated during inflammation remain unclear. Here we show that eosinophils but not other cell types including neutrophils contain nitrotyrosine-positive proteins in specific granules. Furthermore, we demonstrate that the human eosinophil toxins, eosinophil peroxidase (EPO), major basic protein, eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP), and the respective murine toxins, are post-translationally modified by nitration at tyrosine residues during cell maturation. High resolution affinity-mass spectrometry identified specific single nitration sites at Tyr349 in EPO and Tyr33 in both ECP and EDN. ECP and EDN crystal structures revealed and EPO structure modeling suggested that the nitrated tyrosine residues in the toxins are surface exposed. Studies in EPO(-/-), gp91phox(-/-), and NOS(-/-) mice revealed that tyrosine nitration of these toxins is mediated by EPO in the presence of hydrogen peroxide and minute amounts of NOx. Tyrosine nitration of eosinophil granule toxins occurs during maturation of eosinophils, independent of inflammation. These results provide evidence that post-translational tyrosine nitration is unique to eosinophils.     

Development of a chemiluminescent imaging assay for the detection of anti‐erythropoietin antibody in human sera

Measuring low amounts of anti‐erythropoietin antibodies (anti‐EPO Abs) is important to evaluate the therapeutic safety of recombinant human erythropoietin (rhEPO). In this work, a simple, sensitive and high‐throughput chemiluminescent (CL) imaging assay was developed for the detection of anti‐EPO Abs in human sera. The influence of several physicochemical parameters, such as coating conditions, incubation time, detergent concentration and exposure time, were investigated. A calibration curve was established and the range of quantitative detection was 0.12–13.91 ng/mL. The limit of detection (LOD, 3σ) for the CL‐imaging assay was 0.033 ng/mL. Compared to conventional colorimetric enzyme‐linked immunosorbent assay (ELISA), the LOD of the CL‐imaging assay is 50‐fold lower. The recoveries of anti‐EPO Abs in the fortified serum were in the range 87.1–116.9% using the present method, which highlighted the validity of the CL‐imaging assay system to accurately determine the anti‐EPO Abs in serum samples. CL‐imaging assay was used to evaluate the presence of anti‐EPO Abs in serum samples obtained from chronic renal failure (CRF) patients treated with rhEPO. Contrary to what was expected, the sera from CRF patients did not contain anti‐EPO Abs. Copyright © 2008 John Wiley & Sons, Ltd.     

Erythropoietin prevents sepsis-related acute kidney injury in rats by inhibiting NF-κB and upregulating endothelial nitric oxide synthase

The pathophysiology of sepsis involves complex cytokine and inflammatory mediator networks, a mechanism to which NF-κB activation is central. Downregulation of endothelial nitric oxide synthase (eNOS) contributes to sepsis-induced endothelial dysfunction. Erythropoietin (EPO) has emerged as a major tissue-protective cytokine in the setting of stress. We investigated the role of EPO in sepsis-related acute kidney injury using a cecal ligation and puncture (CLP) model. Wistar rats were divided into three primary groups: control (sham-operated); CLP; and CLP+EPO. EPO (4,000 IU/kg body wt ip) was administered 24 and 1 h before CLP. Another group of rats received N-nitro-l-arginine methyl ester (l-NAME) simultaneously with EPO administration (CLP+EPO+l-NAME). A fifth group (CLP+EPOtreat) received EPO at 1 and 4 h after CLP. At 48 h postprocedure, CLP+EPO rats presented significantly higher inulin clearance than did CLP and CLP+EPO+l-NAME rats; hematocrit levels, mean arterial pressure, and metabolic balance remained unchanged in the CLP+EPO rats; and inulin clearance was significantly higher in CLP+EPOtreat rats than in CLP rats. At 48 h after CLP, creatinine clearance was significantly higher in the CLP+EPO rats than in the CLP rats. In renal tissue, pre-CLP EPO administration prevented the sepsis-induced increase in macrophage infiltration, as well as preserving eNOS expression, EPO receptor (EpoR) expression, IKK-α activation, NF-κB activation, and inflammatory cytokine levels, thereby increasing survival. We conclude that this protection, which appears to be dependent on EpoR activation and on eNOS expression, is attributable, in part, to inhibition of the inflammatory response via NF-κB downregulation.     

Eosinophil peroxidase nitrates protein tyrosyl residues. Implications for oxidative damage by nitrating intermediates in eosinophilic inflammatory disorders.

Eosinophil peroxidase (EPO) has been implicated in promoting oxidative tissue injury in conditions ranging from asthma and other allergic inflammatory disorders to cancer and parasitic/helminthic infections. Studies thus far on this unique peroxidase have primarily focused on its unusual substrate preference for bromide (Br(-)) and the pseudohalide thiocyanate (SCN(-)) forming potent hypohalous acids as cytotoxic oxidants. However, the ability of EPO to generate reactive nitrogen species has not yet been reported. We now demonstrate that EPO readily uses nitrite (NO(2)(-)), a major end-product of nitric oxide ((.)NO) metabolism, as substrate to generate a reactive intermediate that nitrates protein tyrosyl residues in high yield. EPO-catalyzed nitration of tyrosine occurred more readily than bromination at neutral pH, plasma levels of halides, and pathophysiologically relevant concentrations of NO(2)(-). Furthermore, EPO was significantly more effective than MPO at promoting tyrosine nitration in the presence of plasma levels of halides. Whereas recent studies suggest that MPO can also promote protein nitration through indirect oxidation of NO(2)(-) with HOCl, we found no evidence that EPO can indirectly mediate protein nitration by a similar reaction between HOBr and NO(2)(-). EPO-dependent nitration of tyrosine was modulated over a physiologically relevant range of SCN(-) concentrations and was accompanied by formation of tyrosyl radical addition products (e.g. o,o'-dityrosine, pulcherosine, trityrosine). The potential role of specific antioxidants and nucleophilic scavengers on yields of tyrosine nitration and bromination by EPO are examined. Thus, EPO may contribute to nitrotyrosine formation in inflammatory conditions characterized by recruitment and activation of eosinophils.     

Anti‐inflammatory effects of doxepin hydrochloride against LPS‐induced C6‐glioma cell inflammatory reaction by PI3K‐mediated Akt signaling

Recent studies have shown that tricyclic antidepressants (TCAs) may have anti‐inflammatory and anticonvulsant effects in addition to its antidepressant effects. So far, the nonantidepressant effects of TCAs and their molecular pharmacological mechanisms remain completely unclear. Chronic inflammation in the brain parenchyma may be related to the pathogenesis and progression of various neurodegenerative diseases. As a common antidepressant and anti‐insomnia drug, doxepin also may be a potential anti‐inflammatory and anticonvulsant drug, so the study on the anti‐inflammatory protective effect of doxepin and its molecular mechanism has become a very important issue in pharmacology and clinical medicine. Further elucidating the anti‐inflammatory and neuroprotective effects of doxepin and its molecular mechanism may provide the important theoretical and clinical basis for the prevention and treatment of neurodegenerative disease. This study was designed to understand the glio‐protective mechanism of doxepin against the inflammatory damage induced by lipopolysaccharide (LPS) exposure in C6‐glioma cells. We found the treatment of C6‐glioma cells with LPS results in deleterious effects, including the augmentation of inflammatory cytokine levels (tumor necrosis factor‐α, interleukin‐1β), and suppresses the Akt phosphorylation. Furthermore, our outcomes demonstrated that doxepin was able to suppress these effects induced by LPS, through activation of the phosphatidylinositol‐3‐kinase‐mediated protein kinase B (Akt) pathway. To sum up, these results highlight the potential role of doxepin against neuroinflammatory‐related disease in the brain.     

Erythropoietin prevents the increase in blood-brain barrier permeability during pentylentetrazol induced seizures

Recombinant human erythropoietin (r-Hu EPO) has been shown to exert neuroprotection in ischemic, excitotoxicity, trauma, convulsions and neurodegenerative disorders. Blood-brain barrier (BBB) leakage plays a role in the pathogenesis of many pathological states of the brain including neurodegenerative disorders. This study aimed to investigate the effects of r-Hu EPO on BBB integrity in pentylentetrazol (PTZ) induced seizures in rats. Seizures were observed and evaluated regard to latency and intensity for an hour. Macroscopical and spectrophotometrical measurement of Evans Blue (EB) leakage were observed for BBB integrity. r-Hu EPO was given intraperitoneally 24 h prior to seizure induction. Total seizure duration of 720+/-50 s after single PTZ administration (80 mg/kg i.p.) was declined to 190+/-40 s in r-Hu EPO pretreatment. A typical BBB breakdown pattern (i.e. staining in cerebellum, cerebral cortex, midbrain, hippocampus, thalamus and corpus striatum) was observed in rat brains with PTZ induced seizures; whereas, EPO pretreatment confined BBB leakage to cerebellum and cortical areas, and lessened the intensity of tonic-clonic seizures observed in PTZ seizures. The protective effect of r-Hu EPO on BBB permeability in seizures is a new and original finding. The protective action of r-Hu EPO in seizures and some of CNS pathologies warrant further investigations.