Reduction Of Inflammatory Infiltration Research Articles

Protection From Arthritis and Myositis in a Mouse Model of Acute Chikungunya Virus Disease by Bindarit, an Inhibitor of Monocyte Chemotactic Protein-1 Synthesis

Chikungunya virus (CHIKV) is associated with outbreaks of infectious rheumatic disease in humans. Using a mouse model of CHIKV arthritis and myositis, we show that tumor necrosis factor-α, interferon-γ, and monocyte chemotactic protein 1 (MCP-1) were dramatically induced in tissues from infected mice. The same factors were detected in the serum of patients with CHIKV-induced polyarthralgia and polyarthritis, with MCP-1 levels being particularly elevated. Bindarit (MCP inhibitor) treatment ameliorated CHIKV disease in mice. Histological analysis of muscle and joint tissues showed a reduction in inflammatory infiltrate in infected mice treated with bindarit. These results suggest that bindarit may be useful in treating CHIKV-induced arthritides in humans.

Critical role for macrophage migration inhibitory factor (MIF) in Ross River virus-induced arthritis and myositis

Arthrogenic alphaviruses, such as Ross River virus (RRV), chikungunya, Sindbis, mayaro and o'nyong-nyong viruses circulate endemically worldwide, frequently causing outbreaks of polyarthritis. The exact mechanisms of how alphaviruses induce polyarthritis remain ill defined, although macrophages are known to play a key role. Macrophage migration inhibitory factor (MIF) is an important cytokine involved in rheumatoid arthritis pathogenesis. Here, we characterize the role of MIF in alphavirus-induced arthritides using a mouse model of RRV-induced arthritis, which has many characteristics of RRV disease in humans. RRV-infected WT mice developed severe disease associated with up-regulated MIF expression in serum and tissues, which corresponded to severe inflammation and tissue damage. MIF-deficient (MIF(-/-)) mice developed mild disease accompanied by a reduction in inflammatory infiltrates and muscle destruction in the tissues, despite having viral titers similar to WT mice. In addition, reconstitution of MIF into MIF(-/-) mice exacerbated RRV disease and treatment of mice with MIF antagonist ameliorated disease in WT mice. Collectively, these findings suggest that MIF plays a critical role in determining the clinical severity of alphavirus-induced musculoskeletal disease and may provide a target for the development of antiviral pharmaceuticals. The prospect being that early treatment with MIF-blocking pharmaceuticals may curtail the debilitating arthritis associated with alphaviral infections.

The CCL3/Macrophage Inflammatory Protein-1α–Binding Protein Evasin-1 Protects from Graft-versus-Host Disease but Does Not Modify Graft-versus-Leukemia in Mice

CCL3 is a protein of the CC chemokine family known to be important for T cell recruitment in inflammatory diseases. The aim of the current study was to evaluate the effects and putative mechanism of action of evasin-1, a novel CCL3-binding protein, in the pathogenesis of acute graft-versus-host disease (GVHD). GVHD was induced by the transplantation of splenocytes from C57BL/6J to B6D2F1 mice. Treatment of recipient mice with evasin-1 prevented mortality associated with GVHD. This was correlated with reduced weight loss and clinical disease severity. Analysis of the small intestine showed that evasin-1 treatment reduced the histopathological score and decreased levels of IFN-gamma and CCL5. Mechanistically, evasin-1 treatment reduced the number of CD4(+) and CD8(+) T cells infiltrating the small intestine, as assessed by immunohistochemistry, and the adhesion of leukocytes to intestinal venules of recipient mice, as assessed by intravital microscopy. Evasin-1 was also able to decrease liver damage, as seen by reduction of inflammatory infiltrate and IFN-gamma levels. Treatment with evasin-1 did not interfere with graft-versus-leukemia. Altogether, our studies demonstrate that CCL3 plays a major role in mediating GVHD, but not graft-versus-leukemia in mice and suggest that blockade of CCL3 with evasin-1 has potential therapeutic application in patients undergoing bone marrow transplantation.

Macrophage‐Derived Proinflammatory Factors Contribute to the Development of Arthritis and Myositis after Infection with an Arthrogenic Alphavirus

Alphaviruses, such as chikungunya virus and Ross River virus (RRV), are associated with outbreaks of infectious rheumatic disease in humans worldwide. Using an established mouse model of disease that mimics RRV disease in humans, we showed that macrophage-derived factors are critical in the development of striated muscle and joint tissue damage. Histologic analyses of muscle and ankle joint tissues demonstrated a substantial reduction in inflammatory infiltrates in infected mice depleted of macrophages (i.e., "macrophage-depleted mice"). Levels of the proinflammatory factors tumor necrosis factor-alpha, interferon-gamma, and macrophage chemoattractant protein-1 were also dramatically reduced in tissue samples obtained from infected macrophage-depleted mice, compared with samples obtained from infected mice without macrophage depletion. These factors were also detected in the synovial fluid of patients with RRV-induced polyarthritis. Neutralization of these factors reduced the severity of disease in mice, whereas blocking nuclear factor kappaB by treatment with sulfasalazine ameliorated RRV inflammatory disease and tissue damage. To our knowledge, these findings are the first to demonstrate that macrophage-derived products play important roles in the development of arthritis and myositis triggered by alphavirus infection.

The Role of Sphingosine Kinase in a Murine Model of Allergic Asthma

Asthma is an allergic disease characterized by chronic airway eosinophilia and pulmonary infiltration of lymphocytes, particularly of the Th2 subtype, macrophages and mast cells. Previous studies have shown a pivotal role for sphingosine kinase (SphK) on various proinflammatory cells, such as lymphocyte and eosinophil migration and mast cell degranulation. We therefore examined the roles of SphK in a murine model of allergic asthma. In mice previously sensitized to OVA, i.p. administration of N,N-dimethylsphingosine (DMS), a potent SphK inhibitor, significantly reduced the total inflammatory cell infiltrate and eosinophilia and the IL-4, IL-5, and eotaxin levels in bronchoalveolar lavage fluid in response to inhaled OVA challenge. In addition, DMS significantly suppressed OVA-induced inflammatory infiltrates and mucus production in the lungs, and airway hyperresponsiveness to methacholine in a dose-dependent manner. OVA-induced lymphocyte proliferation and IL-4 and IL-5 secretion were reduced in thoracic lymph node cultures from DMS-treated mice. Moreover, similar reduction in inflammatory infiltrates, bronchoalveolar lavage, IL-4, IL-5, eotaxin, and serum OVA-specific IgE levels was observed in mice with SphK1 knock-down via small interfering RNA approach. Together, these data demonstrate the therapeutic potential of SphK modulation in allergic airways disease.

Protective Effect of an Inhibitor of Interleukin-8 (Meraxin) From Ischemia and Reperfusion Injury in a Rat Model of Kidney Transplantation

Introduction Since the ischemia and reperfusion injury is one of the main causes of delayed graft function after transplantation, research efforts have focused on studying the molecules involved in this inflammatory process. The chemokine interleukin-8 (IL-8) seems to be the main one responsible through a chemoattractive action toward neutropils. Therefore, one of the strategies adopted to prevent this process is blocking the binding between IL-8 and its receptors. The aim of our study was to test the effect of meraxin, a new derivative from repertaxin, to protect the renal graft from ischemia and reperfusion injury. Materials and methods Eighty male syngenic rats were divided into four groups. The control group underwent only kidney transplantation, while the other groups were treated with meraxin at various dosages 2 hours before graft reperfusion. Blood and histological samples were taken at sacrifice 24 hours after transplantation. Results Creatinine was significantly lower in the group treated with the high dosage of meraxin. Histological observation of the grafted tissue showed instead only a mild and not significant neutrophilic infiltration, equal in each group. Conclusions Graft function was improved by the administration of meraxin at high dosage, but this effect did not seem to be connected to a reduction in inflammatory infiltration in the parechymal tissue. Maybe the cause is in the mechanisms of clotting activation, due to alteration of adhesion molecules and endothelial cells.

Therapeutic Potential of Ovarian Monocyte Progenitor Cells (MPCs) in SLE-Murine Model.

We have previously shown that the progeny of resident ovarian stromal progenitor cells is restricted to the production of cells of the monocyte-macrophage lineage. These ovarian monocyte progenitor cells (MPCs) formed hematopoietic colonies on methyl cellulose, and were CD45+, CD11b+, CD11c+, and Ly6-Gr-1. A distinct CD45low population within these cells reacted with CD117 (C-kit) surface marker, suggestive of a primitive hematopoietic progenitor. To determine the therapeutic potential of MPCs, we transplanted 50,000 cells into normal and autoimmune BXSB autoimmune mouse model for SLE. MPCs did not rescue lethally irradiated mice from the consequences of irradiation, and were not engrafted in MHC-mismatched mouse strains. However, murine SLE-like symptoms were improved, and substantial reduction in inflammatory infiltrate was observed in tissue sections from transplanted mice including kidneys, lungs, and spleen. Restructuring of renal glomerural sclerosis was also observed in the transplant recipients. To determine whether glomerular vascular regeneration was directly mediated by donor MPCs, we tested the hypothesis that MPCs co-express markers for endothelial progenitor cells and monocytes. After culture in conditions permissible to endothelial cell differentiation, large percentage of MPCs (73%) expressed endothelial cell marker CD106. When their culture supernatant was applied to a rat aortic ring in matrigel tube forming assay, robust tube formation was observed in the experimental group. However, similar tube formation was also observed in the control well containing 20% FBS, and cultured MPCs failed to produce tube formation in matrigel assay. Interestingly, phenotypic analysis showed that only 52% of MPCs express MHC class I suggesting that these cells may induce less rejection when transplanted in mismatched hosts. These data suggest that vascular tissue repair initiated by MPCs is mediated by anti-inflammatory factors, and not by direct contribution to the reconstruction of glomeular vasculature.

Effects of Glatiramer Acetate and Interferon-β on Neurodegeneration in a Model of Multiple Sclerosis: A Comparative Study

Axonal destruction and neuronal loss occur early during multiple sclerosis (MS), an autoimmune inflammatory central nervous system disease that frequently manifests with acute optic neuritis. Glatiramer acetate (GA) and interferon-beta-1b (IFN-beta-1b) are two immunomodulatory agents that have been shown to decrease the frequency of MS relapses. However, the question of whether these substances can slow neurodegeneration in MS patients is the subject of controversy. In a rat model of experimental autoimmune encephalomyelitis, we investigated the effects of GA and IFN-beta-1b on the survival of retinal ganglion cells (RGCs), the neurons that form the axons of the optic nerve. For each substance, therapy was started 14 days before immunization, on the day of immunization, or on the day of clinical disease onset. After myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis became clinically manifest, optic neuritis was monitored by recording visual evoked potentials. The function of RGCs was measured by electroretinograms. Although early GA or IFN-beta-1b treatment showed benefit on disease activity, only treatment with GA exerted protective effects on RGCs, as revealed by measuring neurodegeneration and neuronal function. Furthermore, we demonstrate that this GA-induced neuroprotection does not exclusively depend on the reduction of inflammatory infiltrates within the optic nerve.

G Protein-Coupled Receptor Kinase 2 in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis

Many modulators of inflammation, including chemokines, neuropeptides, and neurotransmitters signal via G protein-coupled receptors (GPCR). GPCR kinases (GRK) can phosphorylate agonist-activated GPCR thereby promoting receptor desensitization. Here we describe that in leukocytes from patients with active relapsing-remitting multiple sclerosis (MS) or with secondary progressive MS, GRK2 levels are significantly reduced. Unexpectedly, cells from patients during remission express even lower levels of GRK2. The level of GRK2 in leukocytes of patients after stroke, a neurological disorder with paralysis but without an autoimmune component, was similar to GRK2 levels in cells from healthy individuals. In addition, we demonstrate that the course of recombinant myelin oligodendrocyte glycoprotein (1-125)-induced experimental autoimmune encephalomyelitis (EAE), an animal model for MS, is markedly different in GRK2(+/-) mice that express 50% of the GRK2 protein in comparison with wild-type mice. Onset of EAE was significantly advanced by 5 days in GRK2(+/-) mice. The earlier onset of EAE was associated with increased early infiltration of the CNS by T cells and macrophages. Although disease scores in the first phase of EAE were similar in both groups, GRK2(+/-) animals did not develop relapses, whereas wild-type animals did. The absence of relapses in GRK2(+/-) mice was associated with a marked reduction in inflammatory infiltrates in the CNS. Recombinant myelin oligodendrocyte glycoprotein-induced T cell proliferation and cytokine production were normal in GRK2(+/-) animals. We conclude that down-regulation of GRK2 expression may have important consequences for the onset and progression of MS.

Regenerating More Than Muscle in Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a progressive muscle-wasting disorder of skeletal and cardiac muscle. Mutations in the dystrophin gene produce DMD, but much is still unknown about the pathophysiology of DMD. Dystrophic muscle is defined by replacement of normal myofibers by connective tissue and adipocytes. Normal skeletal muscle is highly regenerative and, in the face of continued degeneration, muscle regeneration in DMD is robust, although insufficient to match the pace of degeneration. The dystrophin protein is a subsarcolemmal, spectrin repeat–containing protein of skeletal muscle myofibers and cardiomyocytes. Dystrophin associates tightly with a constellation of transmembrane proteins forming the dystrophin-glycoprotein complex (DGC). Extracellularly, the DGC binds to laminin 2, and intracellularly, the DGC binds to cytoplasmic γ-actin, a myocyte-specific form of filamin and neuronal nitric oxide synthase (nNOS). Positioned at the plasma membrane, the DGC is a mechanosignaling complex that connects the extracellular matrix with the cytoskeleton, and dystrophin is central to this role.1 When dystrophin is absent, as is the case in DMD, the entire DGC is destabilized. The dissolution of the DGC produces plasma membrane instability associated with increased intracellular calcium and myofiber degeneration. See p 3341 The ongoing and widespread muscle degeneration in DMD produces a number of systemic responses. In the present issue of Circulation , Straino and colleagues2 now show that arteriogenesis is enhanced in mdx mice, a mouse model of DMD. Under ischemic conditions, an increase in hindlimb perfusion was seen in mdx as compared with control mice. As an explanation of increased perfusion, muscle from mdx mice was found to have longer arterioles compared with control muscle. Interestingly, capillary density was not increased, and the observed difference in blood flow was attributed solely to arteriole length differences consistent with enhanced arteriogenesis. Given the prominent regeneration that is a feature of mdx muscle, …

A novel anti-inflammatory role of simvastatin in a murine model of allergic asthma.

Statins, the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, are effective serum cholesterol-lowering agents in clinical practice, and they may also have anti-inflammatory properties. Asthma is characterized by chronic eosinophilic inflammation in the airways, which is thought to be regulated by the activity of T lymphocytes. We therefore examined the anti-inflammatory activity of simvastatin in a murine model of allergic asthma. In mice previously sensitized to OVA, simvastatin treatment, either orally or i.p., reduced the total inflammatory cell infiltrate and eosinophilia in bronchoalveolar lavage fluid in response to inhaled OVA challenge. Simvastatin therapy i.p. was also associated with a reduction in IL-4 and IL-5 levels in bronchoalveolar lavage fluid and, at higher doses, a histological reduction in inflammatory infiltrates in the lungs. OVA-induced IL-4, IL-5, IL-6, and IFN-gamma secretion was reduced in thoracic lymph node cultures from simvastatin-treated mice. Simvastatin treatment did not alter serum total IgE or OVA-specific IgG1 and IgG2a levels. These data demonstrate the therapeutic potential of statin-sensitive pathways in allergic airways disease.

Skin allograft rejection is suppressed in mice lacking the antiviral enzyme, 2',5'-oligoadenylate-dependent RNase L.

The 2-5A/RNase L system is a regulated RNA decay pathway that mediates some of the antiviral and tumor suppressor activities of the interferons. Previously, we demonstrated that RNase L-null mice have increased susceptibility to viral infections and are partially deficient in induced and spontaneous apoptosis. To determine if RNase L functions in cellular, as well as innate, immunity, skin allograft rejection and contact hypersensitivity (CHS) experiments were performed in RNase L+/+ and RNase L-/- mice. Although no consistent alterations in CHS were found, we did observe a delay of 5 days in the acute rejection of class II major histocompatibility complex (MHC) disparate skin allografts in mice lacking RNase L. Accordingly, histologic examinations of the allografts harvested from RNase L-/- mice revealed a dramatic reduction in inflammatory infiltrates, suggesting a delay in T-cell priming or a deficiency in immune cell trafficking. Results consistent with a proinflammatory role for RNase L extend the known functions of the 2-5A/RNase L system beyond innate immunity into some, but not all, types of cellular immunity.

Safety and efficacy of mometasone furoate aqueous nasal spray in children with allergic rhinitis: Results of recent clinical trials

Intranasal mometasone furoate (MF) has been extensively studied in adults and has been found to be safe and effective therapy for the treatment of allergic rhinitis. Several studies have now been conducted on pediatric patients. In all, 990 pediatric patients given mometasone furoate nasal spray (MFNS) have been studied in phase I, II, and III clinical trials. In a dose-ranging study, 5 doses of nasal spray (25, 100, and 200 μg MFNS daily and 168 μg beclomethasone dipropionate daily) were compared with placebo. The 100- and 200-μg daily doses of MFNS were found to be more effective than 168 μg beclomethasone dipropionate or 25 μg MFNS given daily. MFNS (100 μg once daily) was chosen as the appropriate dose. In clinical efficacy and safety trials, MFNS was given to 381 patients 3 to 11 years of age for 4 weeks (357 patients received 100 μg MFNS daily for 6 months) and was found to decrease symptom scores from baseline significantly better than placebo. The long-term safety of MFNS was also studied in 166 patients treated for one year; no significant changes in intraocular pressure were detected. Cosyntropin stimulation showed no decreases in cortisol. In adults, nasal mucosa showed improvement in appearance of epithelium and reduction of inflammatory infiltrates, and there were no signs of nasal atrophy. (J Allergy Clin Immunol 2001;108:S54-8.)

Comparison of cyclosporin A and dexamethasone in the treatment of canine nictitans plasmacytic conjunctivitis

Thirteen dogs with nictitans plasmocytic conjunctivitis were treated with 2.0 per cent cyclosporin drops in the right eye and with 0.1 per cent dexamethasone ointment in the left eye. The...

Morphology of heart valves preserved by liquid nitrogen freezing.

As a preliminary to establishing a frozen valve bank for replacement surgery, the possible effects of the proposed freezing and thawing procedure on tissue structure were assessed in 16 human pulmonary valves removed from cadavers at necropsy and nine dog valves obtained fresh. The valves were frozen and stored in liquid nitrogen for intervals ranging from 23 to 380 days. Blocks of tissue cut from the central area of one leaflet, and including some adjacent arterial wall and ventricular myocardium, were obtained both before freezing and after thawing and examined by a large specimen resin embedding technique for light and electron microscopy, with histochemical staining for matrix material. Control and thawed tissue from all valves appeared similar, indicating good preservation irrespective of storage time. Fine structural alterations in the cellular elements correlated with the total interval of autolysis (from death to freezing) rather than the cause of death or other variables and were not uniform in any of the specimens.