Independent pathways of P-selectin and complement-mediated renal ischemia/reperfusion injury

Evidence from in vitro studies indicates that complement activation regulates the expression of P-selectin on endothelial cells. This suggests that in disorders such as ischemia/reperfusion injury, in which both complement and P-selectin have been shown to play a role, complement activation is a primary event and the effects of P-selectin are secondary. To test this hypothesis in vivo, we examined a mouse kidney model of ischemia/reperfusion injury. Surprisingly, the time course and extent of expression of P-selectin was unaltered in C3-deficient mice compared with wild-type mice, in which there was rapid but transient up-regulation of P-selectin on capillary walls and slower accumulation of complement split product on the tubular epithelium. In addition, treatment with anti-P-selectin antibody to reduce the neutrophil-mediated reperfusion damage was equally effective in the absence of C3. These data imply that complement and P-selectin-mediated pathways of renal reperfusion injury are mutually independent, a conclusion that is possibly explained by the differences in the location and time kinetics of complement activation and P-selectin expression. We conclude that in vivo interaction between complement and P-selectin is limited because of time and spatial considerations. Consequently, complement and P-selectin pose distinct targets for therapy.     

Potential role for IL-23 in hepatic ischemia/reperfusion injury

Summary. IL-12 and IL-23 are related cytokines that share a p40 subunit. Our previous studies identified IL-12 as a primary initiator of the cytokine cascade induced after hepatic ischemia/reperfusion. Because those studies were conducted prior to the discovery of IL-23, it is not clear whether IL-12 or IL-23 is the relevant cytokine in this response. The current studies show that the antibodies used in our original study cross-react with IL-23. We also found that both IL-12 p35 and IL-23 p19 mRNA are expressed rapidly in the liver after ischemia/reperfusion. Finally, isolated Kupffer cells produced TNFα in response to IL-23, but not IL-12, suggesting that IL-23 may be the relevant initiator of the hepatic inflammatory response to ischemia/reperfusion. Received 19 August 2005; returned for revision 5 December 2005; accepted by K. Visvanathan 27 January 2006     

Morphological aspects of LFA-1/ICAM-1 and VLA4/VCAM-1 adhesion pathways in human lymph nodes

Monoclonal antibodies specific for the adhesion molecules participating in lymphocyte homing, lymphocyte function associated antigen-1 (LFA-1) and very late antigen 4 (VLA4), and their respective ligands, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), were used to characterize their expression pattern in human lymph nodes by immunohistochemical and immunoelectron microscopic techniques. The location of LFA-1-positive lymphocytes and selective expression of ICAM-1 on the luminal plasma membrane of high endothelial venule endothelium suggested that the LFA-1/ICAM-1 adhesion pathway participates only in the initial step of the lymphocyte migration process. Lymphocytes passing through endothelium appear not to be influenced by this pathway. VCAM-1 was detected occasionally on the endothelium of high endothelial venules in the hyperplastic lymph nodes in the mesentery, but not in peripheral lymph nodes. VLA4-positive lymphocytes tended to be more frequently observed within high endothelial venules in mesenteric lymph nodes than in peripheral ones. Strong expression of both ligands, ICAM-1 and VCAM-1, was noted on the plasma membrane of follicular dendritic cells, and was especially prominent on their labyrinthine folding, and on the interdigitating cells in the paracortex. Furthermore, both LFA-1-and VLA4-positive lymphocytes localized around these cells. This suggests that LFA-1/ICAM-1 and VLA4/VCAM-1 adhesion pathways play an important role in the lymphocyte recognition of antigen-presenting cells.     

IL-13对大鼠急性肾缺血再灌注时IL-1β表达的影响

目的:观察IL-13对急性肾缺血再灌注时IL-1β表达的影响。方法:Wistar雄性大鼠57只,随机分为8组:正常组(normal);假手术组(sham);缺血组:(I)缺血再灌注组(I/R);治疗对照组-1(C-1);治疗对照组-2(C-2);治疗组-1(T-1)和治疗组-2(T-2)。阻断大鼠双侧肾脏血流45min再灌注24h建立急性肾缺血再灌注模型;治疗组分别于阻断血流前、后分别从双侧肾动脉开口注射入1.5μg/50gbw鼠重组白细胞介素13(rmIL-13);检测各组大鼠IL-1β血清水平和肾脏表达,以及肾功能和肾脏病理。结果:(1)治疗组肾脏IL-1β基因(TtoC:P＜0.01)和蛋白表达(T-1toC-1:P＜0.01;T-2toC-2:P＜0.05)明显减少,血清IL-1β水平明显下降;(2)肾功能障碍和肾组织病理变化明显减轻,肾小管损害评分减少(C-1toT-1:45.20±8.64to21.05±8.82,P＜0.01;C-2toT-2:42.25±11.15to23.25±7.31,P＜0.01);(3)血清IL-1β水平与BUN、Cr成正相关(r=0.708,P＜0.01;r=0.770,P＜0.01)。结论:IL-13能有效地抑制大鼠急性肾缺血再灌注损伤IL-1β的表达。     

Anti-ribonucleoprotein antibodies mediate enhanced lung injury following mesenteric ischemia/reperfusion in Rag-1(-/-) mice

Natural Abs and autoantibodies bind antigens displayed by ischemia-conditioned tissues, followed by complement activation and enhanced tissue injury during reperfusion. Anti-ribonucleoprotein (RNP) Ab is associated with lung disease in patients with autoimmune disease but it is not known whether these abs contribute to lung injury. Mesenteric I/R in mice leads to local and remote lung injury. Accordingly, we used this model to investigate whether anti-RNP Abs would reconstitute I/R damage with prominent lung damage in injury-resistant Rag1(-/-) animals. Rag1(-/-) mice injected with anti-RNP Ab containing serum and subjected to mesenteric I/R suffered greater intestinal injury than control-treated and sham-operated animals. The magnitude of the reconstituted damage was anti-RNP Ab titer-dependent. Anti-RNP Ab-treated animals demonstrated a dose-dependent increase in lung histologic injury scores compared to control and sham animals. Anti-RNP mediated injury was shown to be complement dependent. These experiments reveal a novel mechanism whereby anti-RNP Abs contributes to the development of pulmonary pathology in patients with autoimmune diseases following exposure of remote organs to I/R injury.     

电针预处理通过上调Peroxiredoxin 6减轻大鼠脑缺血再灌注损伤

目的:探讨Peroxiredoxin 6(Prx 6)在电针预处理诱导的SD大鼠脑缺血耐受中的作用。方法:健康雄性SD大鼠80只,随机分为4组:假手术组(Sham组,n=16)、单纯电针组(Electro acupuncture组,EA组,n=16)、局灶性脑缺血再灌注组[通过大脑中动脉栓塞制作脑缺血再灌注(middle cerebral artery occlusion,MCAO)模型,MCAO组,n=32],其中2、6、12、24、48 h各4只和电针预处理组(EA+MCAO组,n=16)。通过梗死容积及神经功能评分(Garcia评分)评价脑损伤程度;通过Western Blot检测Prx 6在脑缺血再灌注后的表达水平;通过Western Blot和免疫组织化学染色法检测电针预处理对Prx 6表达的影响。结果:与MCAO组相比,EA+MCAO组梗死容积减少,神经功能评分显著改善(P0.05);与Sham组相比,Prx 6在MCAO模型后再灌注24 h时表达最高(P0.05);与Sham组相比,再灌注后24 h时MCAO组Prx 6表达水平升高(P0.05);与MCAO组相比,再灌注后24 h时EA+MCAO组Prx 6的表达水平进一步升高(P0.05)。结论:电针预处理通过促进缺血再灌注后Prx 6的表达升高而发挥脑保护作用。     

自噬与心肌缺血/再灌注损伤

Autophagy is a lysosome-dependent degradative pathway which is characterized by cytoplasmic vacuolization. However, it is not just a simple degradative pathway. Research shows that autophagy is related to many diseases, such as neurodegenerative disease, malignant tumor, ageing, pathogenic microorganism infection, myocardial ischemia/reperfusion injury and so on. Autophagy exactly exists in myocardial ischemia/reperfusion injury, and it becomes a new research hotspot. This review will focus on the occurrence and development of autophagy and its role, signal transduction and research status in myocardial ischemia/reperfusion injury.     

缺血-再灌注肝脏组织中ICAM-1基因的表达

目的：探讨肝脏缺血-再灌注过程中肝窦内皮细胞ICAM-1 mRNA的表达规律及其意义。方法：应用分子杂交技术,观察缺血时间分别15、30及45 min的3组兔肝脏于再灌注60 min时ICAM-1 mRNA的表达情况,并对肝窦腔内的白细胞数量进行计数。结果：3组肝脏缺血前及缺血末组织内仅有少量ICAM-1 mRNA表达于肝窦内皮细胞浆内,且肝窦腔内的白细胞数量也无明显改变;但于再灌注60 min时,ICAM-1 mRNA表达程度则显著增强,且缺血时间越长的肝脏,其表达强度越大。此外,组织内ICAM-1 mRNA含量越高的肝脏,肝窦腔内白细胞数量越多,两者呈显著的正相关关系。结论：肝脏的缺血能明显诱导再灌注期间肝窦内皮细胞表达ICAM-1,增强肝窦内皮细胞的粘附力,促进再灌注血流中的白细胞在肝窦内滞留,进而引发一系列病理生理改变。     

Engeletin protects against cerebral ischemia/reperfusion injury by modulating the VEGF/vasohibin and Ang-1/Tie-2 pathways

Engeletin is a natural derivative of Smilax glabra rhizomilax that exhibits anti-inflammatory activity and suppresses lipid peroxidation. In the present study, we sought to elucidate the mechanistic basis for the neuroprotective and pro-angiogenic activity of engeltin in a human umbilical vein endothelial cells (HUVECs) oxygen-glucose deprivation and reoxygenation (OGD/R) model system and a middle cerebral artery occlusion (MCAO) rat model of cerebral ischemia and reperfusion injury. These analyses revealed that engeletin (10, 20, or 40 mg/kg) was able to reduce the infarct volume, increase cerebral blood flow, improve neurological function, and bolster the expression of vascular endothelial growth factor (VEGF), vasohibin-2 (Vash-2), angiopoietin-1 (Ang-1), phosphorylated human angiopoietin receptor tyrosine kinase 2 (p-Tie2), and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) in MCAO rats. Similarly, engeletin (100, 200, or 400 nM) markedly enhanced the migration, tube formation, and VEGF expression of HUVECs in an OGD/R model system, while the VEGF receptor (R) inhibitor axitinib reversed the observed changes in HUVEC tube formation activity and Vash-2, VEGF, and CD31 expression. These data suggested that engeletin exhibited significant neuroprotective effects against cerebral ischemia and reperfusion injury in rats, and improved cerebrovascular angiogenesis by modulating the VEGF/vasohibin and Ang-1/Tie-2 pathways.     

丙泊酚对大鼠肾缺血/再灌注损伤细胞凋亡信号通路的影响

目的探讨丙泊酚对大鼠肾缺血/再灌注损伤细胞凋亡通路的影响及可能的作用机制。方法建立大鼠肾缺血/再灌注损伤模型,将动物分为对照(Con)组、缺血再灌注(IR)组、缺血再灌注 丙泊酚(IR P)组。观察损伤肾的形态学改变,用免疫组织化学观察细胞凋亡相关蛋白BCL-2、BAX、caspase3和细胞色素C(cytochrome C)的表达情况。结果光镜可观察到肾缺血/再灌注引起的肾损害,损害程度依次为近曲小管、远曲小管、集合管、肾小球;免疫组化图像分析观察到IR组与Con组相比,BAX、caspase3,细胞色素C表达增加,BCL-2表达未见明显变化;IR P组与IR组比较,前者BAX、caspase3和细胞色素C表达下降,BCL-2表达增高(P<0·05)。结论丙泊酚对肾缺血/再灌注损伤引起的细胞凋亡可能具有保护作用,可能机制是抑制促凋亡蛋白BAX、caspase3和细胞色素C的表达,对BCL-2的表达无影响,与细胞凋亡的线粒体通路途径有关。     

IL-17 producing CD4 T cells mediate accelerated ischemia/reperfusion-induced injury in autoimmunity-prone mice

Elements of the innate and adaptive immune response have been implicated in the development of tissue damage after ischemic reperfusion (I/R). Here we demonstrate that T cells infiltrate the intestine of C57BL/6 mice subjected to intestinal I/R during the first hour of reperfusion. The intensity of the T cell infiltration was higher in B6.MRL/lpr mice subjected to intestinal I/R and reflected more severe tissue damage than that observed in control mice. Depletion of T cells limited I/R damage in B6.MRL/lpr mice, whereas repletion of B6.MRL/lpr lymph node-derived T cells into the I/R-resistant Rag-1^−/− mouse reconstituted tissue injury. The tissue-infiltrating T cells were found to produce IL-17. Finally, IL-23 deficient mice, which are known not to produce IL-17, displayed significantly less intestinal damage when subjected to I/R. Our data assign T cells a major role in intestinal I/R damage by virtue of producing the pro-inflammatory cytokine IL-17.     

NADPH氧化酶与脑缺血/再灌注损伤

氧化应激是发生脑缺血/再灌注(ischemia/reperfusion,I/R)损伤的重要机制.近来研究发现,还原型烟酰胺腺嘌呤二核苷酸磷酸(nicotinamide adenine dinucleotide phosphate,NADPH)氧化酶产生的活性氧对脑I/R后的氧化应激起到重要的作用.一些方法(如常压高氧、缺血后处理)和一些药物(如罗布麻宁、替米沙坦、桦木酸、加兰他敏、雷公藤红素等)可以NADPH氧化酶为靶点治疗脑I/R损伤.     

Microplate ELISAs for soluble VCAM-1 and ICAM-1

Soluble vascular cell adhesion molecule (sVCAM-1) and soluble intercellular adhesion molecule (sICAM-1) are adhesion molecules that are detectable in the serum of patients with cancer, cardiovascular diseases (CVD), and type 2 diabetes. This report describes enzyme-linked immunosorbent assays (ELISAs) on microplates for sVCAM-1 and sICAM-1. The ELISAs have the sandwich test format; polyclonal antibodies are coated on microwells and a one-step procedure is used in which the serum specimen and detecting antibody are added simultaneously to an antibody-coated well. These assays both use HRP-conjugated sheep anti-mouse-IgG to generate the color for quantification. Sensitivities for detecting sVCAM-1 and sICAM-1 are 49 and 40 ng/ml, respectively. Coefficients of variation for within-day and day-to-day replicate analyses are <10%. Results by these in-house ELISAs for serum sVCAM-1 and sICAM-1 compared well with those obtained with commercial kits from R&D Systems, Inc. (correlation coefficients = 0.98 and 0.99 for sVCAM-1 and sICAM-1, respectively). Reference values for serum sVCAM-1 and sICAM-1 levels were measured in 369 apparently healthy Chinese adults, age 30 to 79 yr. There was no significant effect of gender on the reference values for sVCAM-1 or sICAM-1. Serum sVCAM-1 levels (mean +/- SD) were higher in subjects 60 yr old (625 +/- 126 ng/ml), compared to those <60 yr old (525 +/- 110 ng/ml) (p <0.001). Age did not significantly affect the reference values for serum sICAM-1 levels (mean +/- SD, 249 +/- 86 ng/ml). The authors believe that these simple, inexpensive ELISAs will be useful for assessing the risks for development of cancer, CVD, and type 2 diabetes.     

红花对兔肠缺血再灌注损伤后血IL-8和肠组织ICAM-1表达的影响

目的：观察红花注射液对兔肠缺血再灌注损伤后血白介素8和肠组织细胞间黏附因子1表达变化的影响及其意义。方法：复制在体兔肠缺血再灌注损伤模型。30只日本大耳兔,随机均分为3组：假手术组（S组）、缺血再灌注组（IR组）和缺血再灌注+红花注射液组（SI组）。分别于缺血前、再灌注0、1、2、3 h检测兔血清白介素8的浓度;并采用免疫组织化学法检测各组肠组织标本细胞间黏附因子1(ICAM)表达的改变,作对比分析。结果：IR组血清白细胞介素8水平随缺血和再灌注时间的延长而逐渐升高,缺血和再灌注各时点均明显高于S组（均P<0.01）;SI组稍有上升变化,且明显低于IR组上升程度;细胞间黏附因子1 蛋白在肠组织血管内皮细胞中有表达,尤其在黏膜下层中表达显著,S组兔肠表达较弱,IR组肠血管上皮细胞上 ICAM-1 蛋白表达增强,SI组 ICAM-1蛋白表达明显低于IR组。结论：红花在兔肠缺血再灌注损伤中能抑制白细胞介素8和血管内皮细胞细胞间黏附因子1的表达,有效减少中性粒细胞的黏附、浸润,减轻炎性渗出,抑制微循环通透性的增加,减轻小肠的组织损伤。     

APE/Ref-1蛋白与脑缺血/再灌注神经元损伤

Cerebral ischemia and the aftermath of reperfusion form a hypoxic/hyperoxic sequence of events that can trigger DNA damage in neurons of central nervous system.Neuronal apoptosis will happen without immediate DNA repair.APE/Ref-1 is a multifunctional protein involoved in DNA base excision repair pathway and in redox reguiation of DNA-binding activity of AP-1 family members.which may play an important role in protection of postischemic neuronal damage.     

苦参素降低大鼠肾脏缺血-再灌注损伤

目的观察苦参素的抗大鼠肾缺血再灌注损伤的作用并从抗氧化方面探讨其机制。方法用双肾肾蒂夹闭45 min建立IRI模型,将SD大鼠随机分为假手术组(sham);缺血再灌注组(I/R);苦参素治疗组(oxymatrine+I/R)。苦参素治疗组又分为高、中和低3个剂量组,在缺血再灌注前,连续7 d经腹腔注射。用自动生化仪测定血清肌酐(Scr)和尿素氮(BUN)水平,观察苦参素对肾缺血再灌注的保护作用及确定最优剂量;以最优剂量干预用分光分析法测定肾组织丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)水平。结果不同剂量组均能明显减轻肾脏IRI的病理形态学改变,改善肾功能。与I/R组相比,再灌注72 h后,MDA水平,血清肌酐(Scr)和尿素氮(BUN)水平明显降低(P<0.05);苦参素治疗组的CAT、T-SOD、GSH-Px活性改善明显(P<0.05)。苦参素无体外抗氧化作用。结论苦参素对大鼠肾缺血再灌注损伤具有保护作用,作用机制可能与调控机体的抗氧化系统有关。     

CHIP与心肌缺血/再灌注损伤

Carboxyl terminus of the HSP70-interacting protein (CHIP) is a co-chaperone of HSPs as well as an E3 ubiquitin ligase, and it is the connexin between heat shock proteins and ubiquitin-proteasome system. Recent research discovered that CHIP also possesses an intrinsic chaperone activity that enables it to recognize and bind nonnative proteins independently. CHIP regulates the HSPs expression and activity, and facilitates the client proteins ubiquitination and subsequent proteasome-dependent degradation. CHIP also inhibits apoptosis through MAPKs signaling pathways, and affects eNOS specific activity by means of the effects on Akt. Moreover, CHIP plays an important role in mitochondrial oxidative stress protection. With these above points, this paper reviews the function of CHIP in myocardial ischemia/reperfusion injury.     

Lymphocyte function during hepatic ischemia/reperfusion injury

The liver is the primary organ affected by ischemia/reperfusion (I/R) injury after shock, surgical resection, or transplantation. The actions of myeloid leukocytes have been well studied and are thought to be the primary cells responsible for propagating the injury response. However, there is an emerging view that T lymphocytes can also regulate liver I/R-induced inflammation. Resident lymphocytes found within the liver include conventional alphabeta TCR cells as well as unconventional NK and gammadelta T cells. These lymphocytes can alter inflammation through the secretion of soluble mediators such as cytokines and chemokines or through cognate interactions in an antigen-dependent manner. Expression of these mediators will then result in the recruitment of more lymphocytes and neutrophils. There is evidence to suggest that T cell activation in the liver during I/R can be driven by antigenic or nonantigenic mechanisms. Finally, immune cells are exposed to different oxygen tensions, including hypoxia, as they migrate and function within tissues. The hypoxic environment during liver ischemia likely modulates T cell function, at least in part through the actions of hypoxia-inducible factor-1alpha. Further, this hypoxic environment leads to the increased concentration of extracellular adenosine, which is generally known to suppress T cell proinflammatory function. Altogether, the elucidation of T lymphocyte actions during liver I/R will likely allow for novel targets for therapeutic intervention.     

Annexin 1 mimetic peptide protects against renal ischemia/reperfusion injury in rats

Inflammation is currently recognized as a key mechanism in the pathogenesis of renal ischemia–reperfusion (I/R) injury. The importance of infiltrating neutrophil, lymphocytes, and macrophage in this kind of injury has been assessed with conflicting results. Annexin 1 is a protein with potent neutrophil anti-migratory activity. In order to evaluate the effects of annexin A1 on renal I/R injury, uninephrectomized rats received annexin A1 mimetic peptide Ac2-26 (100 μg) or vehicle before 30 min of renal artery clamping and were compared to sham surgery animals. Annexin A1 mimetic peptide granted a remarkable protection against I/R injury, preventing glomerular filtration rate and urinary osmolality decreases and acute tubular necrosis development. Annexin A1 infusion aborted neutrophil extravasation and attenuated macrophage infiltration but did not prevent tissue lymphocyte traffic. I/R increased annexin A1 expression (assessed by transmission electron microscopy) in renal epithelial cells, which was attenuated by exogenous annexin A1 infusion. Additionally, annexin A1 reduced I/R injury in isolated proximal tubules suspension. Annexin A1 protein afforded striking functional and structural protection against renal I/R. These results point to an important role of annexin A1 in the epithelial cells defense against I/R injury and indicate that neutrophils are key mediators for the development of tissue injury after renal I/R. If these results were confirmed in clinical studies, annexin A1 might emerge as an important tool to protect against I/R injury in renal transplantation and in vascular surgery.