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Macrophage Accumulation (macrophage + accumulation)
Selected AbstractsBlockade of Macrophage Colony-Stimulating Factor Reduces Macrophage Proliferation and Accumulation in Renal Allograft RejectionAMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2003Matthew D. Jose Macrophage accumulation within an acutely rejecting allograft occurs by recruitment and local proliferation. To determine the importance of M-CSF in driving macrophage proliferation during acute rejection, we blocked the M-CSF receptor, c-fms, in a mouse model of acute renal allograft rejection. C57BL/6 mouse kidneys (allografts, n = 20) or BALB/c kidneys (isografts, n = 5) were transplanted into BALB/c mice. Anti-c-fms antibody (AFS98) or control Ig (50 mg/kg/day, i.p.) was given daily to allografts from days 0,5. All mice were killed day 6 postoperatively. Expression of the M-CSF receptor, c-fms, was restricted to infiltrating CD68+ macrophages. Blockade of c-fms reduced proliferating (CD68+/BrdU+) macrophages by 82% (1.1 v 6.2%, p < 0.001), interstitial CD68+ macrophage accumulation by 53% (595 v 1270/mm2, p < 0.001), and glomerular CD68+ macrophage accumulation by 71% (0.73 V 2.48 CD68+ cells per glomerulus, p < 0.001). Parameters of T-cell involvement (intragraft CD4+, CD8+ and CD25+ lymphocyte numbers) were not affected. The severity of tubulointerstitial rejection was reduced in the treatment group as shown by decreased tubulitis and tubular cell proliferation. Macrophage proliferation during acute allograft rejection is dependent on the interaction of M-CSF with its receptor c-fms. This pathway plays a significant and specific role in the accumulation of macrophages within a rejecting renal allograft. [source] The role of endothelin-1 and the endothelin B receptor in the pathogenesis of hepatopulmonary syndrome in the ratHEPATOLOGY, Issue 6 2004Yiqun Ling Endothelin-1 (ET-1) stimulation of endothelial nitric oxide synthase (eNOS) via pulmonary endothelial endothelin B (ETB) receptors and pulmonary intravascular macrophage accumulation with expression of inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1) are implicated in experimental hepatopulmonary syndrome (HPS) after common bile duct ligation (CBDL). Our aim was to evaluate the role of ET-1 in the development of experimental HPS. The time course of molecular and physiological changes of HPS and the effects of selective endothelin receptor antagonists in vivo were assessed after CBDL. Effects of ET-1 on intralobar pulmonary vascular segment reactivity and on eNOS expression and activity in rat pulmonary microvascular endothelial cells (RPMVECs) were also evaluated. Hepatic and plasma ET-1 levels increased 1 week after CBDL in association with a subsequent increase in pulmonary microvascular eNOS and ETB receptor levels and the onset of HPS. Selective ETB receptor inhibition in vivo significantly decreased pulmonary eNOS and ETB receptor levels and ameliorated HPS. CBDL pulmonary artery segments had markedly increased ETB receptor mediated, nitric oxide dependent vasodilatory responses to ET-1 compared with controls and ET-1 triggered an ETB receptor dependent stimulation of eNOS in RPMVECs. Pulmonary intravascular macrophages also accumulated after CBDL and expressed HO-1 and iNOS at 3 weeks. Selective ETB receptor blockade also decreased macrophage accumulation and iNOS production. In conclusion, ET-1 plays a central role in modulating pulmonary micovascular tone in experimental HPS. (HEPATOLOGY 2004;39:1593,1602.) [source] Human plasminogen kringle 1,5 reduces atherosclerosis and neointima formation in mice by suppressing the inflammatory signaling pathwayJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2010P. C. CHANG Summary.,Background:,Activation of vascular endothelial cells plays an important role in atherogenesis and plaque instability. Recent research has demonstrated that late-stage inhibition of plaque angiogenesis by angiostatin (kringle 1,4) reduces macrophage accumulation and slows the progression of advanced atherosclerosis. Kringle 1,5 (K1,5) is a variant of angiostatin that contains the first five kringle domains of plasminogen. Objective: To investigate whether K1,5 has an inhibitory effect on early-stage atherosclerosis, using the apolipoprotein E (ApoE)-deficient mouse model and a carotid artery ligation model. Methods: ApoE-deficient mice received K1,5 treatment for 4 weeks, and the severity of aortic atherosclerosis was measured. In the ligation model, the left common carotid arteries of C57BL/6 mice were ligated near the carotid bifurcation, and the mice received K1,5 for 4 weeks. Human umbilical vein endothelial cells were pretreated with K1,5 before tumor necrosis factor-, (TNF-,) treatment to explore the anti-inflammatory effect of K1,5. Results: The areas of the lesion in the aortas of ApoE-deficient mice that received K1,5 treatment were notably decreased, and the formation of carotid neointima in the C57BL/6 mice was decreased by treatment with K1,5. Expression of TNF-,-induced intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 was inhibited by K1,5 treatment, possibly via downregulation of translocation of nuclear factor-,B and expression of reactive oxygen species. Conclusions: K1,5 reduced atherosclerosis and neointima formation in mice, possibly through inhibition of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression in endothelial cells. [source] Extracellular signal-regulated kinase-dependent interstitial macrophage proliferation in the obstructed mouse kidneyNEPHROLOGY, Issue 5 2008YINGJIE HAN SUMMARY: Aim: A number of growth factors have been shown to induce proliferation of renal cell types in animal models of kidney disease. In vitro studies suggest that many such growth factors induce renal cell proliferation through the extracellular signal-regulated kinase (ERK) pathway. The aim of this study was to determine the functional role of ERK signalling in cell proliferation in the obstructed kidney. Methods: Unilateral ureteric obstruction was induced in C57BL/6J mice which then received an ERK inhibitor drug (U0126 100 mg/kg t.i.d.), vehicle (DMSO) or no treatment, starting at day 2 after unilateral ureteric obstruction surgery and continuing until animals were killed on day 5. Cell proliferation was assessed by uptake of bromodeoxyuridine (BrdU). Results: In normal mice, phosphorylation (activation) of ERK (p-ERK) was restricted to collecting ducts. Western blotting identified a marked increase in p-ERK in the obstructed kidney in the no-treatment and vehicle-treated groups. Immunostaining showed strong p-ERK staining in many tubules and in interstitial cells. U0126 treatment inhibited ERK phosphorylation as assessed by western blot and immunostaining. The number of BrdU+ cortical tubular cells was reduced by vehicle treatment but was not further changed by U0126 treatment. In contrast, interstitial cell proliferation in the obstructed kidney was unaltered by vehicle treatment, but this was significantly inhibited by U0126. This was associated with a reduction in interstitial macrophage accumulation, but no effect was seen upon interstitial accumulation of ,-SMA+ myofibroblasts. Renal fibrosis, as assessed by collagen deposition, was unaffected by U0126 or vehicle treatment. Conclusion: These studies show that accumulation of interstitial macrophages in the obstructed kidney is, in part, dependent upon the ERK signalling pathway. [source] Chemokine responses in schistosomal antigen-elicited granuloma formation,PARASITE IMMUNOLOGY, Issue 6 2002Bo-Chin Chiu Summary Host immune systems have evolved specialized responses to multicellular parasites. This is well represented by the type 2 granulomatous response to Schistosoma mansoni egg antigens, which is an eosinophil-rich inflammatory response mediated by Th2-associated cytokines. Using Ag-bead models of pulmonary granuloma formation in mice, we defined characteristic chemokine (CK) profiles in the granulomatous lungs. Our findings point to a role for C-C chemokine receptor-2 (CCR2) and CCR3 agonists such as monocyte chemotactic proteins (MCPs) 1/CCL2, 3/CCL7 and 5/CCL12 as important participants that are subject to regulation by Th2 cytokines interleukin (IL)-4 and IL-13. CCR4 and CCR8 agonists are also likely contributors. Analysis of CK receptor knockout mice revealed that CCR2 ligands (e.g. MCP-1 and 5) promoted early phase granuloma macrophage accumulation, whereas anti-MCP-3 (CCL7) antibody treatment abrogated eosinophil recruitment. CCR8 knockout mice also demonstrated impaired eosinophil recruitment but this appeared to be related to impaired Th2 cell function. Transcript analysis of CD4+ T cells generated during schistosome granuloma formation failed to show biased CCR8 expression but, having a more limited receptor repertoire, these cells were likely more dependent on CCR8 ligands. Together, these studies indicate an intricate involvement of chemokines in various stages and aspects of schistosomal egg Ag-elicited granuloma formation. [source] Development and fate of crescentic and granulomatous lesions in rat Masugi nephritisPATHOLOGY INTERNATIONAL, Issue 2 2001Tetsuro Horio It has been observed that with Masugi nephritis in Wistar rats the initiation of endocapillary proliferative changes with macrophage accumulation is usually followed by glomerular sclerosis without extracapillary extension. In the present study, the provocation of an extracapillary lesion was attempted using accelerated Masugi nephritis in Wistar,Kyoto rats. In order to accelerate the accumulation of monocyte/macrophages, the administration of methylcellulose was added in an additional group. The development and fate of extracapillary lesions were analyzed histopathologically and immunohistochemically. As a result, the formation of extracapillary proliferation of granulomatous lesions could be initiated in this model. Granulomatous lesions were composed of CD4+ T cells and CD8+ T cells and monocyte/macrophages including multinucleated giant cells. These inflammatory cells had seemingly escaped from the capillary lumen through the injured glomerular basement membrane and formed cellular and granulomatous crescents. In addition, tenascin was strongly expressed in cellular crescents and was a unique extracellular matrix at this cellular stage. The cellular crescents then progressed to sclerosis with the formation of increased collagenous extracellular matrix. These results suggest that a delayed-type hypersensitivity plays a role in granulomatous crescent formation, even though the initial glomerular injury was evoked by a humoral antibody. [source] Glomerular and tubular induction of the transcription factor c-Jun in human renal disease,THE JOURNAL OF PATHOLOGY, Issue 2 2007MH De Borst Abstract The transcription factor c-Jun regulates the expression of genes involved in proliferation and inflammation in many cell types but its role in human renal disease is largely unclear. In the current study we investigated whether c-Jun activation is associated with human renal disease and if c-Jun activation regulates pro-inflammatory and pro-fibrotic genes in renal cells. Activation of c-Jun was quantified by scoring renal expression of phosphorylated c-Jun (pc-Jun) in control human renal tissue and in biopsies from patients with various renal diseases (diabetic nephropathy, focal glomerulosclerosis, hypertension, IgA nephropathy, membranous glomerulopathy, minimal change disease, membranoproliferative glomerulonephritis, systemic lupus erythematosus, acute rejection, and Wegener's granulomatosis); this was correlated with parameters of renal damage. Furthermore, we studied the functional role of c-Jun activation in human tubular epithelial cells (HK-2) stimulated with TGF-,. Activated c-Jun was present in nuclei of glomerular and tubular cells in all human renal diseases, but only sporadically in controls. Across the diseases, the extent of pc-Jun expression correlated with the degree of focal glomerulosclerosis, interstitial fibrosis, cell proliferation, kidney injury molecule-1 (Kim-1) expression, macrophage accumulation, and impairment of renal function. In HK-2 cells, TGF-, induced c-Jun activation after 1 h (+40%, p < 0.001) and 24 h (+160%, p < 0.001). The specific c-Jun N-terminal kinase (JNK) inhibitor SP600125 abolished c-Jun phosphorylation at all time points and blunted TGF-,- or BSA-induced procollagen-1, 1 and MCP-1 gene expression in HK-2 cells. We conclude that in human renal disease, the transcription factor c-Jun is activated in glomerular and tubular cells. Activation of c-Jun may be involved in the regulation of inflammation and/or fibrosis in human renal disease. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Blockade of Macrophage Colony-Stimulating Factor Reduces Macrophage Proliferation and Accumulation in Renal Allograft RejectionAMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2003Matthew D. Jose Macrophage accumulation within an acutely rejecting allograft occurs by recruitment and local proliferation. To determine the importance of M-CSF in driving macrophage proliferation during acute rejection, we blocked the M-CSF receptor, c-fms, in a mouse model of acute renal allograft rejection. C57BL/6 mouse kidneys (allografts, n = 20) or BALB/c kidneys (isografts, n = 5) were transplanted into BALB/c mice. Anti-c-fms antibody (AFS98) or control Ig (50 mg/kg/day, i.p.) was given daily to allografts from days 0,5. All mice were killed day 6 postoperatively. Expression of the M-CSF receptor, c-fms, was restricted to infiltrating CD68+ macrophages. Blockade of c-fms reduced proliferating (CD68+/BrdU+) macrophages by 82% (1.1 v 6.2%, p < 0.001), interstitial CD68+ macrophage accumulation by 53% (595 v 1270/mm2, p < 0.001), and glomerular CD68+ macrophage accumulation by 71% (0.73 V 2.48 CD68+ cells per glomerulus, p < 0.001). Parameters of T-cell involvement (intragraft CD4+, CD8+ and CD25+ lymphocyte numbers) were not affected. The severity of tubulointerstitial rejection was reduced in the treatment group as shown by decreased tubulitis and tubular cell proliferation. Macrophage proliferation during acute allograft rejection is dependent on the interaction of M-CSF with its receptor c-fms. This pathway plays a significant and specific role in the accumulation of macrophages within a rejecting renal allograft. [source] Induction of CCR2-dependent macrophage accumulation by oxidized phospholipids in the air-pouch model of inflammationARTHRITIS & RHEUMATISM, Issue 5 2009Alexandra Kadl Objective Macrophages are key players in the pathogenesis of rheumatoid synovitis as well as in atherosclerosis. To determine whether atherogenic oxidized phospholipids potentially contribute to synovial inflammation and subsequent monocyte/macrophage recruitment, we examined the effects of oxidized 1- palmitoyl-2-arachidonoyl- sn -3-glycero-phosphorylcholine (OxPAPC) on chemokine expression and leukocyte recruitment in a facsimile synovium in vivo using the murine air-pouch model. Methods Air pouches were raised by 2 injections of sterile air, and inflammation was induced by injecting either lipopolysaccharide (LPS) or OxPAPC into the pouch lumen. Inflammation was assessed by analysis of inflammatory gene expression using reverse transcription,polymerase chain reaction or immunohistochemical analysis, and leukocytes were quantified in the lavage fluid and in the pouch wall after staining with Giemsa or after enzymatic digestion followed by fluorescence-activated cell sorter analysis. Results Application of OxPAPC resulted in selective recruitment of monocyte/macrophages into the air-pouch wall, but not in the lumen. In contrast, LPS induced both monocyte and neutrophil accumulation in the pouch lumen as well as in the wall. LPS, but not OxPAPC, induced the expression of adhesion molecules E-selectin, P-selectin, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1. OxPAPC increased the expression of the CCR2 ligands monocyte chemotactic protein 1 (MCP-1), MCP-3, and MCP-5, as well as RANTES and growth-related oncogene , (GRO,), while it down-regulated the expression of CCR2 on macrophages. Moreover, oxidized phospholipid,induced macrophage accumulation was abrogated in CCR2,/, mice. Conclusion These data demonstrate that oxidized phospholipids trigger a type of inflammatory response that leads to selective macrophage accumulation in vivo, a process relevant for the pathogenesis of chronic inflammatory rheumatic diseases. [source] Serum interleukin-6 is elevated in symptomatic carotid bifurcation diseaseACTA NEUROLOGICA SCANDINAVICA, Issue 2 2009M. Koutouzis Introduction,,, The levels of circulating proinflammatory cytokines may express the extent of the inflammatory response and their participation in plaque progression and rupture needs to be evaluated. We aimed to investigate differences in circulating levels of proinflammatory cytokines and in plaque infiltration by macrophages between patients undergoing carotid endarterectomy for symptomatic and asymptomatic carotid atherosclerotic disease. Methods,,, One hundred nineteen patients (91 men and 28 women; mean age 66 ± 8 years; range 42,83 years) who underwent carotid endarterectomy for significant (>70%) carotid bifurcation stenosis were enrolled in this study. Patients were characterized as symptomatic (n = 62) or asymptomatic (n = 57) after neurological examination. Serum levels of interleukin-6 (IL-6), tumor necrosis factor-, (TNF-,), IL-1,, serum amyloid A (SAA), and high-sensitivity C-reactive protein (hs-CRP) were evaluated. Macrophage infiltration of the plaque was assessed quantitatively from endarterectomy specimens using the monoclonal antibody CD68. Results,,, Serum IL-6 levels were significantly higher in patients with symptomatic compared with those with asymptomatic carotid disease (3.3 [2.0,6.5] pg/ml vs 2.5 [1.9,4.1] pg/ml, P = 0.02). TNF-,, IL-1,, SAA, and hs-CRP levels did not differ significantly between the two groups. Symptomatic patients had also more intense macrophage accumulation in the carotid plaque compared with asymptomatic patients (0.6 ± 0.1% vs 0.4 ± 0.1%, P < 0.001). Although there were correlations between the levels of the different inflammatory markers, there were no correlation between any of them and the extent of plaque macrophage infiltration. Conclusion,,, Patients with symptomatic carotid atherosclerotic disease have elevated serum IL-6 levels compared with asymptomatic patients. Symptomatic patients have also more intense macrophage infiltration of the atherosclerotic plaque suggesting that inflammatory process may contribute to the destabilization of the carotid plaque. [source] ROLE OF MACROPHAGES IN COMPLICATIONS OF TYPE 2 DIABETESCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 10 2007GH TeschArticle first published online: 15 AUG 200 SUMMARY 1Macrophage accumulation is a feature of Type 2 diabetes and is associated with the development of diabetic complications (nephropathy, atherosclerosis, neuropathy and retinopathy). The present article reviews the current evidence that macrophages contribute to the complications of Type 2 diabetes. 2Macrophage-depletion studies in rodent models have demonstrated a causal role for macrophages in the development of diabetic complications. 3Components of the diabetic milieu (high glucose, advanced glycation end-products and oxidized low-density lipoprotein) promote macrophage accumulation (via induction of chemokines and adhesion molecules) and macrophage activation within diabetic tissues. 4Macrophages mediate diabetic injury through a variety of mechanisms, including production of reactive oxygen species, cytokines and proteases, which result in tissue damage leading to sclerosis. 5A number of existing and experimental therapies can indirectly reduce macrophage-mediated injury in diabetic complications. The present article discusses the use of these therapies, given alone and in combination, in suppressing macrophage accumulation and activity. 6In conclusion, current evidence supports a critical role for macrophages in the evolution of diabetic complications. Present therapies are limited in slowing the progression of macrophage-mediated injury. Novel strategies that are more specific at targeting macrophages may provide better protection against the development of Type 2 diabetic complications. [source] Will the potential of peroxisome proliferator-activated receptor agonists be realized in the clinical setting?CLINICAL CARDIOLOGY, Issue S4 2004Florian Blaschke M.D. Abstract Drugs targeting both peroxisome proliferator-activated receptor-gamma (PPAR-,) agonists (the thiazolidinediones) and PPAR-, (the fibrates) have already been developed for clinical use. However, the thiazolidinediones, currently prescribed to treat hyperglycemia and improve peripheral insulin resistance, may also have cardiovascular benefits that have yet to be fully realized. Animal models of atherosclerosis have shown that the thiazolidinediones reduce the extent of atherosclerotic lesions and inhibit macrophage accumulation. Clinical studies have also shown that these drugs improve the lipid profile of patients at risk of developing atherosclerosis and reduce circulating levels of inflammatory markers. This combination of lower lipid concentrations and reduced inflammation may explain the cardiovascular benefits of this class of drugs. Early trials in patients with coronary stents have reported promising findings, with restenosis rates being greatly reduced with thiazolidinedione therapy. It is hoped that the results of future clinical trials will continue to be encouraging, so that the thiazolidinediones' cardiovascular benefits can be fully realized in the clinic. [source] | ||||||||||