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On the value of therapeutic interventions targeting the complement system in acute myocardial infarction. Transl Res 2017; 182:103-122. [PMID: 27810412 DOI: 10.1016/j.trsl.2016.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 10/05/2016] [Accepted: 10/06/2016] [Indexed: 01/12/2023]
Abstract
The complement system plays an important role in the inflammatory response subsequent to acute myocardial infarction (AMI). The aim of this study is to create a systematic overview of studies that have investigated therapeutic administration of complement inhibitors in both AMI animal models and human clinical trials. To enable extrapolation of observations from included animal studies toward post-AMI clinical trials, ex vivo studies on isolated hearts and proof-of-principle studies on inhibitor administration before experimental AMI induction were excluded. Positive therapeutic effects in AMI animal models have been described for cobra venom factor, soluble complement receptor 1, C1-esterase inhibitor (C1-inh), FUT-175, C1s-inhibitor, anti-C5, ADC-1004, clusterin, and glycosaminoglycans. Two types of complement inhibitors have been tested in clinical trials, being C1-inh and anti-C5. Pexelizumab (anti-C5) did not result in reproducible beneficial effects for AMI patients. Beneficial effects were reported in AMI patients for C1-inhibitor, albeit in small patient groups. In general, despite the absence of consistent positive effects in clinical trials thus far, the complement system remains a potentially interesting target for therapy in AMI patients. Based on the study designs of previous animal studies and clinical trials, we discuss several issues which require attention in the design of future studies: adjustment of clinical trial design to precise mechanism of action of administered inhibitor, optimizing the duration of therapy, and optimization of time point(s) on which therapeutic effects will be evaluated.
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Rienks M, Papageorgiou AP, Frangogiannis NG, Heymans S. Myocardial extracellular matrix: an ever-changing and diverse entity. Circ Res 2014; 114:872-88. [PMID: 24577967 DOI: 10.1161/circresaha.114.302533] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The cardiac extracellular matrix (ECM) is a complex architectural network consisting of structural and nonstructural proteins, creating strength and plasticity. The nonstructural compartment of the ECM houses a variety of proteins, which are vital for ECM plasticity, and can be divided into 3 major groups: glycoproteins, proteoglycans, and glycosaminoglycans. The common denominator for these groups is glycosylation, which refers to the decoration of proteins or lipids with sugars. This review will discuss the fundamental role of the matrix in cardiac development, homeostasis, and remodeling, from a glycobiology point of view. Glycoproteins (eg, thrombospondins, secreted protein acidic and rich in cysteine, tenascins), proteoglycans (eg, versican, syndecans, biglycan), and glycosaminoglycans (eg, hyaluronan, heparan sulfate) are upregulated on cardiac injury and regulate key processes in the remodeling myocardium such as inflammation, fibrosis, and angiogenesis. Albeit some parallels can be made regarding the processes these proteins are involved in, their specific functions are extremely diverse. In fact, under varying conditions, individual proteins can even have opposing functions, making spatiotemporal contribution of these proteins in the rearrangement of multifaceted ECM very hard to grasp. Alterations of protein characteristics by the addition of sugars may explain the immense, yet tightly regulated, variability of the remodeling cardiac matrix. Understanding the role of glycosylation in altering the ultimate function of glycoproteins, proteoglycans, and glycosaminoglycans in the myocardium may lead to the development of new biochemical structures or compounds with great therapeutic potential for patients with heart disease.
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Affiliation(s)
- Marieke Rienks
- From Maastricht University Medical Centre, Maastricht, The Netherlands
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3
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Vistnes M, Aronsen JM, Lunde IG, Sjaastad I, Carlson CR, Christensen G. Pentosan polysulfate decreases myocardial expression of the extracellular matrix enzyme ADAMTS4 and improves cardiac function in vivo in rats subjected to pressure overload by aortic banding. PLoS One 2014; 9:e89621. [PMID: 24595230 PMCID: PMC3940660 DOI: 10.1371/journal.pone.0089621] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 01/21/2014] [Indexed: 01/05/2023] Open
Abstract
Background We hypothesized that cleavage of the extracellular matrix (ECM) proteoglycans versican and aggrecan by ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) proteases, which contributes to stress-induced ECM-reorganization in atherogenesis and osteoarthritis, also play a role in heart failure development. Objectives The primary objective was to identify alterations in expression of ADAMTS versicanases and aggrecanases during development of heart failure, while evaluation of the effects of in vivo modulation of relevant changes in ADAMTS activity constituted the secondary objective. Methods Myocardial levels of versican, aggrecan, and their ADAMTS cleaving proteases were examined in Wistar rats six weeks after aortic banding (AB), and versican and selected ADAMTS versicanases were further analyzed in neonatal cardiomyocytes (NCM) and cardiac fibroblasts (NFB) after stimulation by inflammatory mediators. Based on the initial findings, ADAMTS4 was selected the most promising therapeutic target. Thus, rats with AB were treated with pentosan polysulfate (PPS), a polysaccharide with known ADAMTS4-inhibitory properties, and effects on versican fragmentation, left ventricular function and geometry were evaluated. Results We discovered that myocardial mRNA and protein levels of ADAMTS1 and -4, and mRNA levels of versican, aggrecan, and ADAMTS8 increased after AB, and TNF-α and IL-1β synergistically increased mRNA of versican and ADAMTS4 in NCM and NFB and secretion of ADAMTS4 from NCM. Furthermore, PPS-treatment improved systolic function, demonstrated by an improved fractional shortening (vehicle 48±3% versus PPS 60±1%, p<0.01) after AB. Following PPS-treatment, we observed an ∼80% reduction in myocardial ADAMTS4 mRNA (p = 0.03), and ∼50% reduction in the extracellular amount of the p150 versican fragments (p = 0.05), suggesting reduced versicanase activity. Conclusions Our findings suggest that AB induces an increase in myocardial ADAMTS4 versicanase activity, and that PPS-treatment improved systolic function in the pressure-overloaded heart, holding promise as a novel therapeutic agent in heart failure.
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Affiliation(s)
- Maria Vistnes
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
- * E-mail:
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
- Bjørknes College, Oslo, Norway
| | - Ida G. Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Cathrine R. Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
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Abdel-Haq H, Bossù E. Capillary electrophoresis as a tool for the characterization of pentosan nanoparticles. J Chromatogr A 2012; 1257:125-30. [DOI: 10.1016/j.chroma.2012.07.096] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/03/2012] [Accepted: 07/27/2012] [Indexed: 01/09/2023]
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Abstract
Reperfusion of an organ following prolonged ischemia instigates the pro-inflammatory and pro-coagulant response of ischemia / reperfusion (IR) injury. IR injury is a wide-spread pathology, observed in many clinically relevant situations, including myocardial infarction, stroke, organ transplantation, sepsis and shock, and cardiovascular surgery on cardiopulmonary bypass. Activation of the classical, alternative, and lectin complement pathways and the generation of the anaphylatoxins C3a and C5a lead to recruitment of polymorphonuclear leukocytes, generation of radical oxygen species, up-regulation of adhesion molecules on the endothelium and platelets, and induction of cytokine release. Generalized or pathway-specific complement inhibition using protein-based drugs or low-molecular-weight inhibitors has been shown to significantly reduce tissue injury and improve outcome in numerous in-vitro, ex-vivo, and in-vivo models. Despite the obvious benefits in experimental research, only few complement inhibitors, including C1-esterase inhibitor, anti-C5 antibody, and soluble complement receptor 1, have made it into clinical trials of IR injury. The results are mixed, and the next objectives should be to combine knowledge and experience obtained in the past from animal models and channel future work to translate this into clinical trials in surgical and interventional reperfusion therapy as well as organ transplantation.
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Affiliation(s)
- Yara Banz
- Institute of Pathology, University of Bern, Switzerland
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6
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Pentosan polysulfate inhibits atherosclerosis in Watanabe heritable hyperlipidemic rabbits: differential modulation of metalloproteinase-2 and -9. J Transl Med 2012; 92:236-45. [PMID: 22042083 PMCID: PMC3707145 DOI: 10.1038/labinvest.2011.154] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Pentosan polysulfate (PPS), a heparinoid compound essentially devoid of anticoagulant activity, modulates cell growth and decreases inflammation. We investigated the effect of PPS on the progression of established atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits. After severe atherosclerosis developed on an atherogenic diet, WHHL rabbits were treated with oral PPS or tap water for 1 month. The aortic intima-to-media ratio and macrophage infiltration were reduced, plaque collagen content was increased, and plaque fibrous caps were preserved by PPS treatment. Plasma lipid levels and post-heparin hepatic lipase activity remained unchanged. However, net collagenolytic activity in aortic extracts was decreased, and the levels of matrix metalloproteinase (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP) activity were increased by PPS. Moreover, PPS treatment decreased tumor necrosis factor α (TNFα)-stimulated proinflammatory responses, in particular activation of nuclear factor-κB and p38, and activation of MMPs in macrophages. In conclusion, oral PPS treatment prevents progression of established atherosclerosis in WHHL rabbits. This effect may be partially mediated by increased MMP-2 and TIMP activities in the aortic wall and reduced TNFα-stimulated inflammation and MMP activation in macrophages. Thus, PPS may be a useful agent in inhibiting the progression of atherosclerosis.
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Abstract
Glycosaminoglycans (GAGs) are the most abundant group of heteropolysaccharides found in the body. These long unbranched molecules contain a repeating disaccharide unit. GAGs are located primarily in the extracellular matrix or on the surface of cells. These molecules serve as lubricants in the joints while at the same time providing structural rigidity to cells. Sulodexide is a highly purified glycosaminoglycan composed of a fast mobility heparin fraction as well as dermatan sulfate. Sulodexide differs from other glycosaminoglycans, like heparin, by having a longer half-life and a reduced effect on systemic clotting and bleeding. In addition, sulodexide demonstrates a lipolytic activity that is increased in comparison to heparin. Oral administration of sulodexide results in the release of tissue plasminogen activator and an increase in fibrinolytic activities. An increasing body of research has demonstrated the safety and efficacy of sulodexide in a wide range of vascular pathologies.
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Affiliation(s)
- D Adam Lauver
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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8
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Sakurai-Yamashita Y, Kinugawa H, Niwa M. Neuroprotective effect of pentosan polysulphate on ischemia-related neuronal death of the hippocampus. Neurosci Lett 2006; 409:30-4. [PMID: 17011126 DOI: 10.1016/j.neulet.2006.09.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 09/04/2006] [Accepted: 09/06/2006] [Indexed: 11/24/2022]
Abstract
Pentosan polysulphate (PPS) negatively charged sulphated glycosaminoglycan was studied in ischemia-related hippocampal neuronal death and compared with a low molecular weight of heparin, named dalteparin in rats. Transient global ischemia was produced by four vessel-occlusion, the occlusion of the bilateral common carotid arteries following the electrocautherization of the vertebral arteries. 3mg/kg of PPS or 300IU/kg of dalteparin was administered i.v. immediately after 7min-occlusion/reperfusion. Seven days after the operation, the animals were perfused with 4% paraformaldehyde, and paraffinized coronal brain sections measuring 6microm in thickness were stained with hematoxylin and eosin. Neuronal damage was then estimated as a ratio of the number of degenerated neurons to that of both the surviving and degenerated neurons in three distinct area of the CA1 subfield. The ratio of neuronal death increased with the length of the occlusion-time, at 5, 7 and 10min. Both PPS and dalteparin significantly inhibited the neuronal damage induced by 7min-occlusion. These results demonstrated that both PPS and dalteparin could thus protect brain neurons against ischemia/reperfusion-induced damage thus suggesting that they may be potentially useful therapeutic agents for acute ischemic stroke.
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Affiliation(s)
- Yasuko Sakurai-Yamashita
- Department of Pharmacology 1, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
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Tsujihata M, Tsujikawa K, Tei N, Yoshimura K, Okuyama A. Urinary macromolecules and renal tubular cell protection from oxalate injury: Comparison of normal subjects and recurrent stone formers. Int J Urol 2006; 13:197-201. [PMID: 16643608 DOI: 10.1111/j.1442-2042.2006.01271.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To determine whether urinary macromolecules (UMM), which are the high molecular weight substances in urine, can provide protection against the oxalate-associated injury to the renal tubular cells. METHODS UMM were extracted from 24-h urine of 12 healthy adult male volunteers and 13 recurrent-stone-former male patients. Urine parameters in relation to urolithiasis were measured, including the level of glycosaminoglycans (GAG) in the UMM. Madin-Darby canine kidney (MDCK) cells were used to evaluate the protective activity of UMM from oxalate-induced cytotoxicity by LDH release measurement and methyl-thiazolyl tertrazolium (MTT) assay. RESULTS Considering urinary parameters, citrate was significantly higher in urine from normal subjects than stone-former subjects; the other parameters show no differences between the groups. Total UMM and the level of GAG in the UMM were also significantly higher in the normal subject group. Compared with normal subject and stone-former subject UMM, after cells were treated with the UMM and then exposed to oxalate solution, LDH release was significantly higher in stone-former group. In the MTT assay, we found that more viable cells were observed after treatment with UMM compared to control in both groups. Moreover, UMM from the normal subjects showed higher protective activity against oxalate-related cytotoxicity than UMM from the stone-former subjects. CONCLUSION UMM protected renal epithelial cells from oxalate-related injury. This protective activity was found to be higher in normal subject UMM than stone-former UMM. Among other factors, a higher concentration of GAG and citrate in normal subject UMM might affect some parts in this finding.
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Affiliation(s)
- Masao Tsujihata
- Department of Urology, Osaka University Graduate School of Medicine, Osaka, Japan.
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Xu Y, Huo Y, Toufektsian MC, Ramos SI, Ma Y, Tejani AD, French BA, Yang Z. Activated platelets contribute importantly to myocardial reperfusion injury. Am J Physiol Heart Circ Physiol 2005; 290:H692-9. [PMID: 16199480 DOI: 10.1152/ajpheart.00634.2005] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Platelets become activated during myocardial infarction (MI), but the direct contribution of activated platelets to myocardial reperfusion injury in vivo has yet to be reported. We tested the hypothesis that activated platelets contribute importantly to reperfusion injury during MI in mice. After 30 min of ischemia and 60 min of reperfusion, P-selectin knockout mice had a significantly smaller infarct size than that of wild-type mice (P < 0.05). Platelets were detected by P-selectin antibody in the previously ischemic region of wild-type mice as early as 2 min postreperfusion after 45 min, but not 20 min, of ischemia. The appearance of neutrophils in the heart was delayed when compared with platelets. Flow cytometry showed that the number of activated platelets more than doubled after 45 min of ischemia when compared with 20 min of ischemia or sham treatment (P < 0.05). Platelet-rich or platelet-poor plasma was then transfused from either sham-operated or infarcted mice after 45 and 10 min of ischemia-reperfusion to mice undergoing 20 and 60 min of ischemia-reperfusion. Infarct size was increased by threefold and platelet accumulation was remarkably enhanced in mice treated with wild-type, MI-activated platelet-rich plasma but not in mice receiving either platelet-poor plasma from wild types or MI-activated platelet-rich plasma from P-selectin knockout mice. In conclusion, circulating platelets become activated early during reperfusion and their activation depends on the duration of the preceding coronary occlusion and is proportional to the extent of myocardial injury. Activated platelets play an important role in the process of myocardial ischemia-reperfusion injury, and platelet-derived P-selectin is a critical mediator.
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Affiliation(s)
- Yaqin Xu
- Dept. of Biomedical Engineering, Univ. of Virginia Health System, Charlottesville, VA 22903, USA
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11
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Lauver DA, Booth EA, White AJ, Poradosu E, Lucchesi BR. Sulodexide attenuates myocardial ischemia/reperfusion injury and the deposition of C-reactive protein in areas of infarction without affecting hemostasis. J Pharmacol Exp Ther 2004; 312:794-800. [PMID: 15365091 DOI: 10.1124/jpet.104.075283] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Several glycosaminoglycans (GAGs) have been demonstrated to protect the ischemic heart against reperfusion injury, in part, by modulating activation of the complement cascade. The present study assessed the cardioprotective effects of sulodexide (KRX-101), a mixture of GAGs composed of 80% low-molecular mass heparin and 20% dermatan sulfate. KRX-101 differs from other GAGs (e.g., heparin) in that it has limited anticoagulant efficacy and can be administered orally. The experimental protocol was designed to determine whether KRX-101 could protect the ischemic myocardium. Anesthetized New Zealand white rabbits underwent 30 min of coronary artery occlusion. Intravenous doses of KRX-101 (0.5 mg/kg, n = 10) or drug diluent (n = 10) were administered at the end of regional ischemia and at each hour of reperfusion. Infarct size, as a percentage of the area at risk, was calculated for both groups. Myocardial infarct size was 31.3 +/- 4.1% in the vehicle- and 17.3 +/- 3.2% in the KRX-101-treated animals (p < 0.05 versus vehicle). Activated partial thromboplastin times determined at baseline (preischemia) and at each hour of reperfusion (n = 4) were not significantly different between vehicle- and KRX-101-treated groups (p = N.S.). Myocardial injury was further assessed by measuring serum levels of cardiac-specific troponin I. KRX-101 administration significantly reduced (p < 0.05) the serum concentration of troponin I during reperfusion. The results suggest that KRX-101 may be an effective adjunctive agent in myocardial revascularization procedures, without the risk of increased bleeding.
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Affiliation(s)
- D Adam Lauver
- Department of Pharmacology, University of Michigan Medical School, 1301 MSRB III, Ann Arbor, MI 48109, USA
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12
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Abstract
Neuroinflammation is a characteristic of pathologically affected tissue in several neurodegenerative disorders. These changes are particularly observed in affected brain areas of Alzheimer's disease (AD) cases. They include an accumulation of large numbers of activated microglia and astrocytes as well as small numbers of T-cells, mostly adhering to postcapillary venules. Accompanying biochemical alterations include the appearance or up-regulation of numerous molecules characteristic of inflammation and free radical attack. Particularly important may be the complement proteins, acute phase reactants and inflammatory cytokines. These brain phenomena combined with epidemiological evidence of a protective effect of antiinflammatory agents suggest that such agents may have a role to play in treating the disease.
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Affiliation(s)
- Edith G McGeer
- Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3.
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Prochazka S, Mulholland M, Lloyd-Jones A. Optimisation for the separation of the oligosaccharide, sodium Pentosan Polysulfate by reverse polarity capillary zone electrophoresis using a central composite design. J Pharm Biomed Anal 2003; 31:133-41. [PMID: 12560057 DOI: 10.1016/s0731-7085(02)00569-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The separation by reverse polarity capillary zone electrophoresis of the therapeutically developed sodium salt of Pentosan Polysulfate was optimised through the analysis of response surface methodologies, modeled using a central composite design. The optimisation investigated injection pressure, injection time and voltage and the effect of the conditions on retention times, peak areas, separation efficiency and the method sensitivity. The overall goal was to develop the most sensitive results with no decrease in separation efficiency. The following results were obtained: (1) retention times generally decreased as injection pressure, injection time and voltage increased, injection time having the least effect; (2) as expected peak areas increased as injection pressure and injection time increased but decreased as voltage increased; (3) separation efficiencies generally increased as injection pressure and injection time decreased, with voltage having almost no effect. For the optimum condition, the sample was introduced at the inlet vial at the cathode hydrodynamically, at optimal setting of 44 s at 35 mbar. The optimal voltage was -20 kV. In comparison with other methods, the optimum showed increased sensitivity, resolution and separation efficiency. Repeatability studies were performed on the optimum parameter conditions. Relative standard deviation values obtained were between 0.9 and 5.4%.
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Affiliation(s)
- S Prochazka
- Department of Chemistry, Materials and Forensic Science, University of Technology, Sydney, P.O. Box 123, Broadway, NSW 2001, Australia
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14
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Abstract
Postmortem immunohistochemical studies have revealed a state of chronic inflammation limited to lesioned areas of brain in Alzheimer's disease. Some key actors in this inflammation are activated microglia (brain macrophages), proteins of the classical complement cascade, the pentraxins, cytokines, and chemokines. The inflammation does not involve the adaptive immune system or peripheral organs, but is rather due to the phylogenetically much older innate immune system, which appears to operate in most tissues of the body. Chronic inflammation can damage host tissue and the brain may be particularly vulnerable because of the postmitotic nature of neurons. Many of the inflammatory mediators have been shown to be locally produced and selectively elevated in affected regions of Alzheimer's brain. Moreover, studies of tissue in such degenerative processes as atherosclerosis and infarcted heart suggest a similar local innate immune reaction may be important in such conditions. Much epidemiological and limited clinical evidence suggests that nonsteroidal anti-inflammatory drugs may impede the onset and slow the progression of Alzheimer's disease. But these drugs strike at the periphery of the inflammatory reaction. Much better results might be obtained if drugs were found that could inhibit the activation of microglia or the complement system in brain, and combinations of drugs aimed at different inflammatory targets might be much more effective than single agents.
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Affiliation(s)
- Patrick L McGeer
- Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada.
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15
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Barrett TD, Hennan JK, Marks RM, Lucchesi BR. C-reactive-protein-associated increase in myocardial infarct size after ischemia/reperfusion. J Pharmacol Exp Ther 2002; 303:1007-13. [PMID: 12438521 DOI: 10.1124/jpet.102.040600] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
C-Reactive protein (CRP), a marker for acute inflammation, is associated with increased risk of cardiovascular events. The mechanism underlying this association is uncertain. An acute inflammatory response was induced in rabbits by subcutaneous injection of croton oil (CO) 1 to 3 days before 30 min of regional myocardial ischemia/180 min of reperfusion. CO treatment increased plasma CRP from below the limit of detection to 2.5 +/- 0.5 mg/dl and was associated with an increase in infarct size expressed as percentage of risk region [32 +/- 6% vehicle controls (n = 7) to 47 +/- 9% CO-treated rabbits (n = 7; P < 0.05]. After 10 min of ischemia and 180 min reperfusion, no infarct was found in controls; however, an infarct of 7 +/- 1% was found in CO-treated rabbits (P < 0.05; CRP, 2.3 +/- 0.4 mg/dl). The CRP-related increase in infarct size was not observed in croton oil-treated, C6-deficient rabbits (n = 5/group), indicating the involvement of complement. In these rabbits, infarct size was 22 +/- 2% (P < 0.05) despite having plasma CRP of 4.3 +/- 0.4 mg/dl. The CRP-associated increase in infarct size was ameliorated by pretreatment with heparin (n = 7; infarct size 33 +/- 3%; CRP, 2.3 +/- 0.3 mg/dl; P < 0.05) or N-acetylheparin (n = 7; infarct size 23 +/- 4%; CRP, 3.1 +/- 0.5 mg/dl; P < 0.05). These observations may explain why increased serum CRP is associated with an augmented risk for cardiovascular events.
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Affiliation(s)
- Terrance D Barrett
- University of Michigan Medical School, Department of Pharmacology, Ann Arbor, Michigan, USA
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16
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Abstract
Molecular pathological studies of Alzheimer disease (AD) brain have revealed the presence of a spectrum of inflammatory mediators. Epidemiological studies have indicated that the use of anti-inflammatory agents, especially non-steroidal anti-inflammatory drugs (NSAIDs), results in a substantially reduced risk of contracting the disease. It is possible that well targeted anti-inflammatory agents will also be useful in treating established AD. Inhibitors of cyclooxygenase-2 have been unsuccessful in this regard, and traditional NSAIDs have produced mixed results. The complement system, which is strongly activated in AD brain, is an attractive target for therapeutic intervention, particularly through inhibition of the autodestructive action of the membrane attack complex. The complement system works in conjunction with activated microglia, which express high levels of complement receptors. Overactive microglia secrete many toxic materials. Inhibition of microglial activation is another potential therapeutic target.
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Affiliation(s)
- Patrick L McGeer
- Kinsmen Laboratory of Neurological Research, Dept of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, BC, V6T 1Z3, Vancouver, Canada.
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17
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McGeer PL, McGeer EG. Innate immunity, local inflammation, and degenerative disease. SCIENCE OF AGING KNOWLEDGE ENVIRONMENT : SAGE KE 2002; 2002:re3. [PMID: 14602998 DOI: 10.1126/sageke.2002.29.re3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The brain lesions associated with Alzheimer's disease (AD), which are referred to as neurofibrillary tangles and senile plaques, are characterized by the presence of a broad spectrum of inflammatory mediators. Surprisingly, these mediators, which include complement proteins, inflammatory cytokines, prostaglandins, and acute phase reactants such as C-reactive protein and amyloid P, are produced by resident brain cells, including neurons. Although secondary to the fundamental pathology caused by the presence of tangles and plaques, there is strong evidence that inflammation exacerbates the neuronal loss. In particular, AD lesions show evidence of self-attack by the complement system--a part of the immune system that normally functions to rid the body of invading pathogens. However, the lesions are devoid of significant T cell infiltration, a hallmark of an inflammatory immune response, and antibodies. We define this phenomenon as autotoxicity to distinguish it from classical autoimmunity, in which the body raises antibodies to normal endogenous macromolecules. Locally produced inflammatory mediators have also been identified in atherosclerotic plaques, along with evidence of complement self-attack. As was previously shown for heart attacks, epidemiological evidence indicates that extended use of nonsteroidal anti-inflammatory drugs (NSAIDs) results in a reduced risk of AD. NSAIDs inhibit the production of prostaglandin inflammatory mediators, but powerful new therapeutic agents might be developed by targeting more critical inflammatory mechanisms, especially the complement system.
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Affiliation(s)
- Patrick L McGeer
- Kinsmen Laboratory of Neurological Research at the University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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18
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Sadhukhan PC, Tchetgen MB, Rackley RR, Vasavada SP, Liou L, Bandyopadhyay SK. Sodium Pentosan Polysulfate Reduces Urothelial Responses to Inflammatory Stimuli Via an Indirect Mechanism. J Urol 2002. [DOI: 10.1016/s0022-5347(05)64909-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Provash C. Sadhukhan
- From the Department of Cancer Biology, Lerner Research Institute and Section of Voiding Dysfunction and Female Urology, Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Marie-Blanche Tchetgen
- From the Department of Cancer Biology, Lerner Research Institute and Section of Voiding Dysfunction and Female Urology, Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Raymond R. Rackley
- From the Department of Cancer Biology, Lerner Research Institute and Section of Voiding Dysfunction and Female Urology, Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Sandip P. Vasavada
- From the Department of Cancer Biology, Lerner Research Institute and Section of Voiding Dysfunction and Female Urology, Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Louis Liou
- From the Department of Cancer Biology, Lerner Research Institute and Section of Voiding Dysfunction and Female Urology, Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Sudip K. Bandyopadhyay
- From the Department of Cancer Biology, Lerner Research Institute and Section of Voiding Dysfunction and Female Urology, Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio
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19
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Sodium Pentosan Polysulfate Reduces Urothelial Responses to Inflammatory Stimuli Via an Indirect Mechanism. J Urol 2002. [DOI: 10.1097/00005392-200207000-00093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Klegeris A, Singh EA, McGeer PL. Effects of C-reactive protein and pentosan polysulphate on human complement activation. Immunology 2002; 106:381-8. [PMID: 12100726 PMCID: PMC1782735 DOI: 10.1046/j.1365-2567.2002.01425.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Complement (C) activation is believed to play an adverse role in several chronic degenerative disease processes, including atherosclerosis, myocardial infarction and Alzheimer's disease. We developed several in vitro quantitative assays to evaluate processes which activate C in human serum, and to assess candidates which might block that activation. Binding of C-reactive protein (CRP) to immobilized cell surfaces was used as a tissue-based method of activation, while immunoglobulin G in solution was used as a surrogate antibody method. Activation was assessed by deposition of C fragments on fixed cell surfaces, or by capture of C5b-9 from solution. We observed that several cell lines, including SH-SY5Y, U-937, THP-1 and ECV304, bound CRP and activated C following attachment of cells to a plastic surface by means of air drying. Treatment of human neuroblastoma SH-SY5Y cells with the reactive oxygen intermediates generated by xanthine (Xa) - xanthine oxidase (XaOx) prior to air drying or by hydrogen peroxide solutions after air drying, enhanced C activation, possibly through oxidation of the cell lipid membrane. Several C inhibitors were tested for their effectiveness in blocking these systems. Pentosan polysulphate (PPS), an orally active agent, blocked C activation in the same concentration range of 1-1000 microg/ml as heparin, dextran sulphate, compstatin and fucoidan. PPS may have practical application as a C inhibitor.
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Affiliation(s)
- Andis Klegeris
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, Canada
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21
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Shernan SK, Collard CD. Role of the complement system in ischaemic heart disease: potential for pharmacological intervention. BioDrugs 2002; 15:595-607. [PMID: 11580303 DOI: 10.2165/00063030-200115090-00004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The complement system is an innate, cytotoxic host defence system that normally functions to eliminate foreign pathogens. However, considerable evidence suggests that complement plays a key role in the pathophysiology of ischaemic heart disease (IHD). Experimental models of acute myocardial infarction (MI) and autopsy specimens taken from acute MI patients demonstrate that complement is selectively deposited in areas of infarction. Furthermore, inhibition of complement activation or depletion of complement components prior to myocardial reperfusion has been shown to reduce complement-mediated tissue injury in numerous animal models. IHD remains a leading cause of patient morbidity and mortality. Considerable effort in recent years has therefore been directed by biotechnology and pharmaceutical industries towards the development of novel, human complement inhibitors. Proposed anticomplement therapeutic strategies include the administration of naturally occurring or recombinant complement regulators, anticomplement monoclonal antibodies, and anticomplement receptor antagonists. Although data regarding the effectiveness of anticomplement therapy in humans is limited at present, a number of novel anticomplement therapeutic strategies are currently in clinical trials. The role of complement in IHD and potential for pharmacological intervention is reviewed.
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Affiliation(s)
- S K Shernan
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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22
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Monsinjon T, Richard V, Fontaine M. Complement and its implications in cardiac ischemia/reperfusion: strategies to inhibit complement. Fundam Clin Pharmacol 2001; 15:293-306. [PMID: 11903498 DOI: 10.1046/j.1472-8206.2001.00040.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although reperfusion of the ischemic myocardium is an absolute necessity to salvage tissue from eventual death, it is also associated with pathologic changes that represent either an acceleration of processes initiated during ischemia or new pathophysiological changes that were initiated after reperfusion. This so-called "reperfusion injury" is accompanied by a marked inflammatory reaction, which contributes to tissue injury. In addition to the well known role of oxygen free radicals and white blood cells, activation of the complement system probably represents one of the major contributors of the inflammatory reaction upon reperfusion. The complement may be activated through three different pathways: the classical, the alternative, and the lectin pathway. During reperfusion, complement may be activated by exposure to intracellular components such as mitochondrial membranes or intermediate filaments. Two elements of the activated complement contribute directly or indirectly to damages: anaphylatoxins (C3a and C5a) and the membrane attack complex (MAC). C5a, the most potent chemotactic anaphylatoxin, may attract neutrophils to the site of inflammation, leading to superoxide production, while MAC is deposited over endothelial cells and smooth vessel cells, leading to cell injury. Experimental evidence suggests that tissue salvage may be achieved by inhibition of the complement pathway. As the complement is composed of a cascade of proteins, it provides numerous sites for pharmacological interventions during acute myocardial infarction. Although various strategies aimed at modulating the complement system have been tested, the ideal approach probably consists of maintaining the activity of C3 (a central protein of the complement cascade) and inhibiting the later events implicated in ischemia/reperfusion and also in targeting inhibition in a tissue-specific manner.
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23
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Bos IG, van Mierlo GJ, Bleeker WK, Rigter GM, te Velthuis H, Dickneite G, Hack CE. The potentiation of human C1-inhibitor by dextran sulphate is transient in vivo: studies in a rat model. Int Immunopharmacol 2001; 1:1583-95. [PMID: 11515821 DOI: 10.1016/s1567-5769(01)00073-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
C1-inhibitor (C1-Inh) is an important regulator of inflammatory reactions because it is a potent inhibitor of the contact and complement system. C1-Inh application in inflammatory disease is, however, restricted because of the high doses required. The glycosaminoglycan-like molecule dextran sulphate (DXS) enhances C1-Inh function in vitro. Hence, we investigated whether co-administration with dextran sulphate reduces the amount of C1-Inh required, through enhancement in vivo. C1-Inh potentiation was measured in a newly developed C1s-inactivation assay that is based on activation of C4 by purified C1s. Activated C4 in rat plasma was quantified with a newly developed ELISA. Human C1-Inh (2.5 microM) inhibited C1s in rat plasma 55-fold faster in the presence of dextran sulphate (15 kDa, 5 microM). To study the stability of the complex in vivo, rats were given a mixture of C1-Inh (10 mg/kg) and dextran sulphate (3 mg/kg). C1-Inh activity during 5 h was analyzed ex vivo with the C1s inactivation assay. The noncovalent C1-Inh-dextran sulphate complex resulted in a transient enhancement of the inhibitory capacity of C1-Inh, lasting for 60-90 min. Dextran sulphate did not affect plasma clearance of C1-Inh. We conclude that the enhanced inhibitory capacity of C1-Inh complexed to dextran sulphate is transient in vivo. Hence, co-administration of these compounds seems a feasible approach to achieve short-term inhibition of complement in vivo.
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Affiliation(s)
- I G Bos
- Department of Immunopathology, CLB and Laboratory for Experimental and Clinical Immunology, University of Amsterdam, The Netherlands.
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24
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Braun C, Schultz M, Fang L, Schaub M, Back WE, Herr D, Laux V, Rohmeiss P, Schnuelle P, van der Woude FJ. Treatment of chronic renal allograft rejection in rats with a low-molecular-weight heparin (reviparin). Transplantation 2001; 72:209-15. [PMID: 11477340 DOI: 10.1097/00007890-200107270-00007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Low-molecular-weight heparin (LMWH) has been shown to prolong survival of rat cardiac allografts independently from immunosuppressive treatment. Furthermore, long-term treatment reduces the development of chronic graft vascular disease after experimental heart transplantation. The aim of the present study was to determine whether treatment with the LMWH reviparin has a beneficial effect on chronic rejection in a rat renal allograft model. METHODS Kidneys of Fisher (F344) rats were transplanted into unilaterally nephrectomized Lewis (LEW) recipients. LEW-->LEW isografts served as controls. Animals were treated with cyclosporine (5 mg/kg/d) for the first 10 days. Nephrectomy of the remaining kidney was performed after 10 days. Allografted animals were treated either with reviparin (2 mg/kg/d subcutaneously) for 24 weeks (Allo-24), from week 12 to 24 (Allo-12), or with vehicle for 24 weeks. Proteinuria was determined at regular intervals. Kidneys were harvested after 24 weeks for histomorphological and immunohistochemical evaluation. RESULTS No major bleeding complications were observed in reviparin-treated animals. Proteinuria was significantly reduced in allografted animals both by early as well as by late-onset treatment with reviparin. Transplant glomerulopathy was diminished in Allo-24 and in Allo-12 groups compared to vehicle-treated animals, whereas tubulointerstitial inflammation was influenced only in animals immediately treated with reviparin. Immunohistochemical studies demonstrated a marked reduction of renal monocyte and T-cell infiltration as well as expression of MHC II by treatment with reviparin. CONCLUSIONS Treatment with the LMWH reviparin significantly improved chronic renal allograft rejection in the F344-to-LEW rat model, both after early and late start of therapy. Although the exact mechanisms of this beneficial effect remain unclear, our data offer a potential new therapeutical approach for prevention of chronic allograft nephropathy.
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Affiliation(s)
- C Braun
- V. Department of Medicine (Nephrology/Endocrinology), University Hospital Mannheim, University of Heidelberg, Germany
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25
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Atsuumi T, Yaoita H, Shichishima T, Maehara K, Fujita T, Maruyama Y. Complement and polymorphonuclear leukocyte activation each play a role in determining myocardial ischemia-reperfusion injury. JAPANESE CIRCULATION JOURNAL 2001; 65:659-66. [PMID: 11446502 DOI: 10.1253/jcj.65.659] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cobra venom factor (CVF) transiently activates polymorphonuclear leukocytes (PMN) by complement activation, followed by rapid complement depletion and gradual reversal of PMN activation. Utilizing these sequential changes caused by CVF, the individual and combined effects of complement and PMNs on myocardial infarct size (IS) were investigated. Rats were treated with CVF, and/or anti-PMNs. Complement was depleted, but circulating PMNs were being activated at 4h after CVF administration, and at 36h after, complement was depleted, but PMNs were in a near basal condition. Under anesthesia, the rats had a 30-min coronary occlusion followed by 6h of reperfusion. The IS was assessed by tetrazolium staining. CVF, as well as anti-PMNs, reduced myeloperoxidase (MPO) activity in the risk area and the reduced MPO resulted in a reduced IS, which was also the effect of anti-PMNs, but complement depletion by CVF, during which circulating PMNs were activated, failed to reduce the IS despite low MPO activity. These results suggest that complement and the condition of PMNs each play a role in determining the IS, and ischemic reperfusion injury might be produced even by relatively low myocardial MPO activity.
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Affiliation(s)
- T Atsuumi
- First Department of Internal Medicine, Fukushima Medical University, Japan
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26
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Braun C, Schultz M, Schaub M, Fang L, Back WE, Herr D, Laux V, Schnuelle P, Rohmeiss P, van der Woude FJ. Effect of treatment with low-molecular-weight heparin on chronic renal allograft rejection in rats. Transplant Proc 2001; 33:363-5. [PMID: 11266863 DOI: 10.1016/s0041-1345(00)02049-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C Braun
- Vth Department of Medicine (Nephrology/Endocrinology, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany.
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27
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Deli MA, Abrahám CS, Takahata H, Katamine S, Niwa M. Pentosan polysulfate regulates scavenger receptor-mediated, but not fluid-phase, endocytosis in immortalized cerebral endothelial cells. Cell Mol Neurobiol 2000; 20:731-45. [PMID: 11100980 DOI: 10.1023/a:1007007026500] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
1. Effects of pentosan polysulfate (PPS) and the structurally related sulfated polyanions dextran sulfate, fucoidan, and heparin on the scavenger receptor-mediated and fluidphase endocytosis in GP8 immortalized rat brain endothelial cells were investigated. 2. Using 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarboxyamine perchlorate-labeled acetylated low-density lipoprotein (DiI-AcLDL), we found a binding site with high affinity and low binding capacity, and another one with low affinity and high binding capacity. Increasing ligand concentrations could not saturate DiI-AcLDL uptake. DiI-AcLDL uptake, but not binding, was sensitive to pretreatment with filipin, an inhibitor of caveola formation. 3. PPS (20-200 microg/ml) significantly reduced the binding of DiI-AcLDL after coincubation for 3 hr, though this effect was less expressed after 18 hr. Among other polyanions, only fucoidan decreased the DiI-AcLDL binding after 3 hr, whereas dextran sulfate significantly increased it after 18 hr. PPS treatment induced an increase in DiI-AcLDL uptake, whereas other polysulfated compounds caused a significant reduction. 4. Fluid-phase endocytosis determined by the accumulation of Lucifer yellow was concentration and time dependent in GP8 cells. Coincubation with PPS or other sulfated polyanions could not significantly alter the rate of Lucifer yellow uptake. 5. In conclusion. PPS decreased the binding and increased the uptake of DiI-AcLDL in cerebral endothelial cells, an effect not mimicked by the other polyanions investigated.
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Affiliation(s)
- M A Deli
- Department of Pharmacology 1, Nagasaki University School of Medicine, Japan.
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28
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Tanhehco EJ, Yasojima K, McGeer PL, McGeer EG, Lucchesi BR. Preconditioning reduces myocardial complement gene expression in vivo. Am J Physiol Heart Circ Physiol 2000; 279:H1157-65. [PMID: 10993779 DOI: 10.1152/ajpheart.2000.279.3.h1157] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This investigation examined the effect of preconditioning in an in vivo model of ischemia-reperfusion injury. Anesthetized New Zealand White rabbits underwent 30 min of regional myocardial ischemia followed by 2 h of reperfusion. Hearts preconditioned with two cycles of 5 min ischemia-10 min reperfusion (IPC) or with the ATP-sensitive K (K(ATP)) channel opener, diazoxide (10 mg/kg), exhibited significantly (P < 0.05) smaller infarcts compared with control. These treatments also significantly (P < 0.001 to P < 0.05) reduced C1q, C1r, C3, C8, and C9 mRNA in the areas at risk (AAR). The K(ATP) channel blocker 5-hydroxydecanoate (5-HD; 10 mg/kg) attenuated infarct size reduction elicited by IPC and diazoxide treatment. 5-HD partially reversed the decrease in complement expression caused by IPC but not diazoxide. There were no significant differences in complement gene expression in the nonrisk regions and livers of all groups. Western blot analysis revealed that IPC also reduced membrane attack complex expression in the AAR. The data demonstrate that preconditioning significantly decreases reperfusion-induced myocardial complement expression in vivo.
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Affiliation(s)
- E J Tanhehco
- Department of Pharmacology, University of Michigan Medical School Ann Arbor, Michigan 48109-0632, USA
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29
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Tanhehco EJ, Yasojima K, McGeer PL, Washington RA, Lucchesi BR. Free radicals upregulate complement expression in rabbit isolated heart. Am J Physiol Heart Circ Physiol 2000; 279:H195-201. [PMID: 10899056 DOI: 10.1152/ajpheart.2000.279.1.h195] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both free radicals and complement activation can injure tissue. Our study determined whether free radicals alter complement production by the myocardium. Isolated hearts from New Zealand White rabbits were perfused on a Langendorff apparatus and exposed to xanthine (X; 100 microM) plus xanthine oxidase (XO; 8 mU/ml) (X/XO). The free radical-generating system significantly (P < 0.05) increased C1q and also increased C1r, C3, C8, and C9 transcription compared with controls. Immunohistological examination revealed augmented membrane attack complex deposition on X/XO-treated tissue. X/XO-treated hearts also exhibited significant (P < 0.05) increases in coronary perfusion pressure and left ventricular end-diastolic pressure and a decrease in left-ventricular developed pressure. N-(2-mercaptopropionyl)-glycine (3 mM), in conjunction with the superoxide dismutase mimetic SC-52608 (100 microM), significantly (P < 0.05) reduced the upregulation of C1q, C1r, C3, C8, and C9 mRNA expression elicited by X/XO. The antioxidants also ameliorated the deterioration in function caused by X/XO. Local complement activation may represent a mechanism by which free radicals mediate tissue injury.
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Affiliation(s)
- E J Tanhehco
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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30
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Lucchesi BR, Tanhehco EJ. Therapeutic potential of complement inhibitors in myocardial ischaemia. Expert Opin Investig Drugs 2000; 9:975-91. [PMID: 11060721 DOI: 10.1517/13543784.9.5.975] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Under normal conditions, the complement system functions to eradicate microbes and other membrane bound pathogens. In other situations, complement activation comprises a pivotal mechanism for mediating tissue demolition in inflammatory disorders, including ischaemia/reperfusion injury. Complement-mediated tissue damage has long been recognised as a significant contributor to myocardial reperfusion injury. However, clinical use of complement inhibitors to reduce the extent of irreversible tissue injury related to reperfusion, remains in the early stages of development. Activation of the complement system generates anaphylatoxins, opsonins and the lytic moiety known as the membrane attack complex (MAC). In addition, fragments of the complement cascade proteins (e.g., C3a and C5a) secondarily initiate processes deleterious to myocytes by recruiting and stimulating inflammatory cells, such as neutrophils and macrophages, within the area of reperfusion. Damaged tissue itself, is capable of upregulating the genes that encode the formation of complement proteins leading to assembly of the MAC, which in turn further advances tissue injury. All of these factors contribute to the development of myocardial infarction subsequent to ischaemia and reperfusion. This paper provides an overview of how the complement system operates and examines the various inhibitors, both endogenous and exogenous, that regulate the complement cascade. Activation and inhibition of the complement system will be discussed primarily in the context of myocardial ischaemia and reperfusion injury.
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Affiliation(s)
- B R Lucchesi
- Department of Pharmacology, University of Michigan, A220C, 1301 MSRB III, 1150 West Medical Center Drive, Ann Arbor, MI 48019-0632, USA
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