MIP-1alpha, MCP-1, GM-CSF, and TNF-alpha control the immune cell response that mediates rapid phagocytosis of myelin from the adult mouse spinal cord

The slow immune response in the adult mammalian CNS results in slow myelin phagocytosis along degenerating white matter after injury. This has important consequences for axon regeneration because of the presence of axon growth inhibitors in myelin. In addition, abnormal immune cell responses in the CNS lead to demyelinating disease. Lysophosphatidylcholine (LPC) can induce an inflammatory response in the CNS, producing rapid demyelination without much damage to adjacent cells. In this study, we searched for the molecular switches that turn on this immune cell response. Using reverse transcription PCR analysis, we show that mRNA expression of macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage chemotactic protein-1 (MCP-1), granulocyte macrophage-colony stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha) in the spinal cord is rapidly and transiently upregulated after intraspinal injection of LPC. Neutralizing these signaling molecules with function-blocking antibodies suppresses recruitment of T-cells, neutrophils, and monocytes into the spinal cord, as well as significantly reduces the number of phagocytic macrophages and the demyelination induced by LPC. These findings will have important implications for CNS regeneration and demyelinating disease.

Intratracheal instillation of lipopolysaccharide in mice induces apoptosis in bronchial epithelial cells: no role for tumor necrosis factor-alpha and infiltrating neutrophils

This study investigated apoptosis in lungs after local exposure to lipopolysaccharide (LPS). Mice were instilled intratracheally with 5 microg LPS, which corresponds to the amount acquired by smoking approximately 25 cigarettes, and killed at different time points after exposure. Our data demonstrate that local LPS exposure resulted in apoptosis in lungs from 2 h and peaked at 24 h, as detected by ligation-mediated polymerase chain reaction. Morphologic examination and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end label staining demonstrated apoptosis in bronchial epithelial cells early after intratracheal (IT) LPS challenge, whereas infiltrating neutrophils displayed positive staining at 24 and 72 h after exposure. Apoptosis in lungs clearly preceded pulmonary neutrophil infiltration, confirming that neutrophils did not contribute to pulmonary apoptosis at early time points. Further, using three experimental approaches--namely, anti-tumor necrosis factor (TNF)-alpha treatment, IT TNF-alpha instillation, and TNF/lymphotoxin-alpha knockout mice--we demonstrate that TNF-alpha, which was elevated in lungs at both messenger RNA and protein levels after IT LPS challenge, was no primary mediator in LPS-induced apoptosis at early time points. Thus, local LPS exposure in mice resulted in early apoptosis of bronchial epithelial cells independent of infiltrating neutrophils and TNF-alpha, which suggests that apoptosis of bronchial epithelium may be involved in airway injury during exposure to LPS.

Caveolin-1 peptide exerts cardioprotective effects in myocardial ischemia-reperfusion via nitric oxide mechanism

Caveolin-1 is a protein constituent of cell membranes. The caveolin-1 scaffolding region (residues 82-101) is a known inhibitor of protein kinase C. Inhibition of protein kinase C results in maintained nitric oxide (NO) release from the endothelium, which attenuates cardiac dysfunction after ischemia-reperfusion (I/R). Therefore, we hypothesized that the caveolin-1 scaffolding region of the molecule, termed caveolin-1 peptide, might attenuate postischemia polymorphonuclear neutrophil (PMN)-induced cardiac dysfunction. We examined the effects of caveolin-1 peptide in isolated ischemic (20 min) and reperfused (45 min) rat hearts reperfused with PMNs. Caveolin-1 peptide (165 or 330 microg) given intravenously 1 h before I/R significantly attenuated postischemic PMN-induced cardiac dysfunction, as exemplified by left ventricular developed pressure (LVDP) (P < 0.01) and the maximal rate of developed pressure (+dP/dt(max)) (P < 0.01), compared with I/R hearts obtained from rats given 0.9% NaCl. In addition, caveolin-1 peptide significantly reduced cardiac PMN infiltration from 195 +/- 5 PMNs/mm2 in untreated hearts to 103 +/- 5 and 60 +/- 5 PMNs/mm2 in hearts from 165 and 330 microg caveolin-1 peptide-treated rats, respectively (P < 0.01). PMN adherence to the rat coronary vasculature was also significantly reduced in rats given either 165 or 330 microg caveolin-1 peptide compared with rats given 0.9% NaCl (P < 0.01). Moreover, caveolin-1 peptide-treated rat aortas exhibited a 2.2-fold greater basal release of NO than vehicle-treated aortas (P < 0.01), and this was inhibited by NG-nitro-L-arginine methyl ester. These results provide evidence that caveolin-1 peptide significantly attenuated PMN-induced post-I/R cardiac contractile dysfunction in the isolated perfused rat heart, probably via enhanced release of endothelium-derived NO.

Anti-inflammatory activity of abietic acid, a diterpene isolated from Pimenta racemosa var. grissea

The anti-inflammatory activity of abietic acid, a diterpene isolated from Pimenta racemosa var. grissea (Myrtaceae), was evaluated in-vivo and in-vitro. This compound significantly inhibited rat paw oedema induced by carrageenan in a time- and dose-dependent manner, and mouse ear oedema induced by 12-O-tetradecanoylphorbol acetate, after oral or topical administration. The inhibition of myeloperoxidase enzyme showed that its topical activity was influenced by neutrophil infiltration into the inflamed tissues (ears). In addition, the effect of abietic acid on some macrophage functions was analysed in-vitro. Non-toxic concentrations of abietic acid inhibited prostaglandin E2 (PGE2) production in lipopolysaccharide-treated macrophages, whereas nitrite, tumour necrosis factor alpha and interleukin-1beta production were only weakly affected by this diterpene. PGE2 production from A23187-stimulated macrophages was only inhibited at high doses (100 microM) and it failed to modify leukotriene C4 production. These results indicate that abietic acid exerts in-vivo anti-inflammatory activity after oral or topical administration and has partial ability to prevent the production of some inflammatory mediators.

Protective effect of L-arginine against stress-induced gastric mucosal lesions in rats and its relation to nitric oxide-mediated inhibition of neutrophil infiltration

Pretreatment with l -arginine (150-600 mg kg(-1), i.p.), but not d -arginine (600 mg kg(-1), i.p.), protected against gastric mucosal lesions in rats with water immersion restraint stress over a 6-h period. This protective effect occurred in a dose-dependent manner. Increases in the activities of inducible nitric oxide synthase (iNOS) and myeloperoxidase (MPO), an index of tissue neutrophil infiltration, and the concentration of nitrite/nitrate, breakdown products of nitric oxide, and a decrease in the activity of constitutive nitric oxide synthase (cNOS) occurred in the gastric mucosal tissue with the development of gastric mucosal lesions. The l -arginine pretreatment attenuated the increases in iNOS and MPO activities and nitrite/nitrate concentration and the decrease in cNOS activity in the gastric mucosal tissue in a dose-dependent manner, while the d -arginine pretreatment did not. Both the protective effect of l -arginine (300 mg kg(-1)) against stress-induced gastric mucosal lesions and the attenuating effect of the amino acid on the increases in gastric mucosal iNOS and MPO activities and the decrease in gastric mucosal cNOS activity with the lesion development were counteracted by pretreatment with N(G)-monomethyl- l -arginine (100 mg kg(-1), s.c.), a nitric oxide synthase inhibitor, but not its d -isomer (100 mg kg(-1), s.c.). These results suggest that the protective effect of exogenously administered l -arginine against stress-induced gastric mucosal lesions in rats is, at least in part, due to nitric oxide-mediated inhibition of neutrophil infiltration into the gastric mucosal tissue.

Identification of a selective nonpeptide antagonist of the anaphylatoxin C3a receptor that demonstrates antiinflammatory activity in animal models

The anaphylatoxin C3a is a potent chemotactic peptide and inflammatory mediator released during complement activation which binds to and activates a G-protein-coupled receptor. Molecular cloning of the C3aR has facilitated studies to identify nonpeptide antagonists of the C3aR. A chemical lead that selectively inhibited the C3aR in a high throughput screen was identified and chemically optimized. The resulting antagonist, N(2)-[(2,2-diphenylethoxy)acetyl]-L-arginine (SB 290157), functioned as a competitive antagonist of (125)I-C3a radioligand binding to rat basophilic leukemia (RBL)-2H3 cells expressing the human C3aR (RBL-C3aR), with an IC(50) of 200 nM. SB 290157 was a functional antagonist, blocking C3a-induced C3aR internalization in a concentration-dependent manner and C3a-induced Ca(2+) mobilization in RBL-C3aR cells and human neutrophils with IC(50)s of 27.7 and 28 nM, respectively. SB 290157 was selective for the C3aR in that it did not antagonize the C5aR or six other chemotactic G protein-coupled receptors. Functional antagonism was not solely limited to the human C3aR; SB 290157 also inhibited C3a-induced Ca(2+) mobilization of RBL-2H3 cells expressing the mouse and guinea pig C3aRS: It potently inhibited C3a-mediated ATP release from guinea pig platelets and inhibited C3a-induced potentiation of the contractile response to field stimulation of perfused rat caudal artery. Furthermore, in animal models, SB 290157, inhibited neutrophil recruitment in a guinea pig LPS-induced airway neutrophilia model and decreased paw edema in a rat adjuvant-induced arthritis model. This selective antagonist may be useful to define the physiological and pathophysiological roles of the C3aR.

Immunobiology of CD28 expression on human neutrophils. I. CD28 regulates neutrophil migration by modulating CXCR-1 expression

CD28, described as a T cell costimulatory molecule so far, is expressed on human peripheral blood neutrophils, as shown by cell surface staining and immunoprecipitation with anti-CD28 monoclonal antibody, and by reverse transcription PCR. The phorbol 12-myristate 13-acetate-augmented expression of CD28 on these cells can be blocked by actinomycin D, an RNA transcription inhibitor, and staurosporin, a protein kinase inhibitor. Cross-linking of CD28 results in an early increase in IL-8 receptor A (IL-8RA or CXCR-1) expression and a concurrent increase in IL-8-induced chemotaxis. The expression of CXCR-1 is down-regulated by receptor internalization 3 h after CD28 cross-linking with concurrent decrease in IL-8-induced chemotactic migration. Thus, our results demonstrate for the first time that CD28 is expressed on human peripheral blood neutrophils and that CD28 may play an important role in the regulation of IL-8RA expression and migration of neutrophils in response to IL-8.

Neutrophil defensins mediate acute inflammatory response and lung dysfunction in dose-related fashion

High concentrations of neutrophil defensins from airway and blood have been reported in patients with inflammatory lung diseases, but their exact role is unclear. We investigated the direct effect of defensins on the lungs of mice. Intratracheal instillation of purified defensins (5-30 mg/kg) induced a progressive reduction in peripheral arterial O(2) saturation, increased lung permeability, and enhanced the lung cytochrome c content. These indexes of acute lung dysfunction were associated with an increased total cell number and a significant neutrophil influx into the lung [5.1 +/- 0.04% in control vs. 48.6 +/- 12.7% in the defensin (30 mg/kg) group, P < 0.05]. Elastase concentrations in the bronchoalveolar lavage (BAL) fluids increased from 38 +/- 11 ng/ml (control) to 80 +/- 4 ng/ml (defensins, P < 0.05). Five hours after defensin instillation, concentrations of tumor necrosis factor-alpha and macrophage inflammatory protein-2 in BAL fluid were significantly increased. High levels of monocyte chemoattractant protein-1 in BAL fluid and plasma were also found after defensin stimulation. We conclude that intratracheal instillation of defensins causes acute lung inflammation and dysfunction, suggesting that high concentrations of defensins in the airways may play an important role in the pathogenesis of inflammatory lung diseases.

Estrogen effect on post-exercise skeletal muscle neutrophil infiltration and calpain activity

We hypothesized that estrogen administration would attenuate skeletal muscle neutrophil infiltration, indices of muscle membrane disruption, and muscle calpain activity shortly after the termination of exercise. Ovariectomized female rats were implanted with either an estogen pellet (25 mg beta-estradiol) or a placebo pellet. Two weeks postimplant, animals were killed either at rest or 1 h after running exercise (60 min at 21 m x min(-1), 12% grade). The 4 experimental groups (n = 12) used were: unexercised placebo (UP), unexercised estrogen (UE), exercised placebo (EP), and exercised estrogen (EE). Blood samples were analyzed for creatine kinase (CK) activity and estradiol content. Plantaris and gastrocnemius muscles were removed and histochemical determination of neutrophil content or biochemical determination of myeloperoxidase (MPO), glucose-6-phosphate dehydrogenase (G6PD), and calpain-like activity determined. Estrogen supplemented animals had 10-20-fold higher circulating estradiol levels than placebo animals. EP animals had significantly higher (P < 0.05) circulating CK activities than EE or unexercised animals. Muscle neutrophil concentrations were significantly (P < 0.01) elevated in EP and EE groups compared with unexercised controls, with EP muscle neutrophil levels also being over 60% greater (P < 0.05) than in EE animals. EP animals also had higher (P < 0.05) muscle MPO activities than unexercised or EE animals. Muscle G6PD activities were not significantly different between any groups. Muscle caplain-like activities were 80% higher (P < 0.01) in EP animals than EE animals with calpain-like activities in EE animals similar to unexercised groups. These results indicate that estrogen supplementation in ovariectomized rats attenuated 1-h post-exercise serum CK activities, muscle neutrophil infiltration, MPO activities, and calpain-like activities when compared with exercised, unsupplemented animals. This supports the possibility of a relationship between estrogen, calpain dependent production of neutrophil chemo-attractant peptides, and 1-h post-exercise skeletal muscle neutrophil infiltration.

The effect of the glucocorticoid Oradexon on endotoxin-induced peritoneal cell response

Glucocorticoids are important modulators of immune reactions. They are capable of antagonising several effects of the bacterial endotoxin by inhibiting endotoxin-induced leukocyte activation, and the production of cytokines and inflammatory mediators. We earlier demonstrated that the antiglucocorticoid RU 38486 enhances the cytokine production induced by endotoxin and aggravates the course of experimental endotoxic and septic shock. In the present study we investigated the effect of the glucocorticoid Oradexon on the endotoxin-induced peritoneal cell response. For measurement of the peritoneal cell response, male CFLP mice (20-25 g) were injected i.p. with 10 microg/10 g body weight endotoxin (E. coli 026:B6 LPS, Difco Lab, Detroit, lot 110273JB). Dexamethasone (Oradexon, N.V, Organon Oss, The Netherlands) was administered i.p., i.v. or s.c. in a dose of 0.1 mg/10 g body weight, alone or concomitantly with endotoxin. We found that bacterial endotoxin increased the total cell count due to neutrophilia at 24 hours and, due to increases in the number of macrophages and lymphocytes 48 and 72 hours after treatment, respectively. The i.p., i.v., and s.c. injection of Oradexon, increased the total cell count and the macrophage count at 24, 48 and 72 hours. The i.p., s.c. and i.v. injection of Oradexon, concomitantly with endotoxin, reduced the total cell count at 48 and 72 hours, due to decreases in the macrophage count. The i.p., i.v. or s.c. administration of Oradexon concomitantly with LPS decreased the lymphocyte count and the neutrophil count at 24 and 72 hours. These results prove that glucocorticoids are capable of modifying the immune cell reactions induced by endotoxin.

Endotoxin enhancement of ozone-induced mucous cell metaplasia is neutrophil-dependent in rat nasal epithelium

Ozone, the primary oxidant gas in photochemical smog, causes neutrophilic inflammation and mucous cell metaplasia (MCM) in the nasal transitional epithelium (NTE) of rats and monkeys. Bacterial endotoxin is another common airborne agent that induces acute neutrophilic inflammation, but not MCM, in NTE. It does, however, enhance ozone-induced MCM in rat nasal airways (Fanucchi et al., 1998, Toxicol. Appl. Pharmacol. 152, 1-9). In the present study, F344 rats exposed to filtered air or 0.5 ppm ozone (8 h/day for 3 days) were intranasally instilled with sterile saline or 100 microg endotoxin 24 h and 48 h after the third ozone exposure. To determine the role of neutrophilic inflammation in endotoxin-induced potentiation of the MCM caused by ozone, half of the rats were depleted of circulating neutrophils prior to saline or endotoxin instillations. Rats were killed 6 h or 3 days after the last intranasal instillation, and nasal tissues were processed for (1) light microscopy and morphometric analysis to determine the number of infiltrating neutrophils and the volume amount (density) of stored mucosubstances in the NTE, and (2) quantitative RT-PCR analysis of steady-state mucin gene (rMuc-5AC) mRNA levels in the NTE. Endotoxin induced a transient influx of neutrophils in both air- and ozone-exposed rats that was completely blocked by neutrophil depletion. Endotoxin increased rMuc-5AC mRNA levels in the NTE of ozone-exposed rats. Neutrophil depletion, however, had no effect on endotoxin-induced upregulation of mucin gene mRNA levels. Endotoxin enhanced the ozone-induced increase in stored mucosubstances (4-fold increase), but only in neutrophil-sufficient rats. These data indicate that endotoxin enhancement of ozone-induced upregulation of rMuc-5AC mRNA levels is neutrophil-independent, while its effects on intraepithelial production and storage of mucus glycoproteins is dependent on the presence of neutrophils.

Attenuation of interleukin 8-induced nasal inflammation by an inhibitor peptide

Polymorphonuclear neutrophils (PMNs) infiltrate tissue in response to chemoattractants, including interleukin 8 (IL-8). Infiltrating PMNs clear microorganisms but also cause tissue damage. We previously reported the presence in human bronchial lavage of a peptide that inhibits PMN functions. The current project assessed (1) effects of a synthetic analog of this peptide (synthetic neutrophil inhibitor peptide, SNIP) on IL-8-induced nasal inflammation in humans, (2) effects of SNIP on PMN apoptosis and chemotaxis, (3) specific binding of SNIP to PMNs, and (4) evidence of larger molecules with the SNIP sequence. Results show that SNIP attenuates IL-8-induced nasal inflammation, inhibits in vitro PMN chemotaxis to IL-8, and accentuates PMNs apoptosis. PMNs contain specific SNIP-binding sites and the integrin CR3 (CD11b/CD18), or a CR3-associated molecule, is one SNIP-binding molecule. Chemotaxis to IL-8 is most potently inhibited by SNIP in the presence of fibrinogen, a CR3 ligand. Antiserum against the SNIP sequence recognizes a 70-kDa protein in bronchoalveolar lavage and an anti-SNIP immunoaffinity column binds a 70-kDa protein in U937 cell culture supernatant. U937 cell mRNA contains a 1.8-kb transcript detected with degenerate oligonucleotides designed from the SNIP sequence. These studies demonstrate that a synthetic inhibitor peptide can attenuate in vivo nasal inflammation through downregulatory effects on PMNs.

The IL-8 release from cultured human keratinocytes, mediated by antibodies to bullous pemphigoid autoantigen 180, is inhibited by dapsone

Bullous pemphigoid (BP) is a subepidermal blistering disease associated with autoantibodies to the hemidesmosomal 180 kD BP autoantigen (BP180). However, the binding of autoantibodies to BP180 alone is not sufficient for blister formation in this disease and the infiltration of neutrophils into the skin is required. Dapsone and nicotinamide inhibit neutrophil chemotaxis and are used effectively in treating BP. IL-8 is a known chemoattractant for neutrophils and has been implicated in the inflammatory process of both human and experimental murine BP. We have recently shown that antibodies to BP180 mediate a dose and time-dependent release of IL-6 and IL-8 from cultured normal human epidermal keratinocytes (NHEK). In the present study, we addressed the question whether dapsone or nicotinamide influence this cytokine release. We demonstrate that dapsone, but not nicotinamide, in its pharmacological range, inhibits the IL-8, but not the IL-6 release from NHEK, induced by anti-BP180 IgG, in a dose-dependent fashion as detected by ELISA. IL-8 mRNA levels, as determined by RT-PCR, were the same in cells treated with BP IgG alone compared to cells treated with BP IgG plus dapsone. This observation suggests that dapsone inhibits the BP IgG-induced IL-8 release from cultured NHEK by mechanisms at the post-transcriptional level. Our findings contribute to the understanding how dapsone leads to a reduced influx of neutrophils into BP lesions and, finally, to the cessation of blister formation in this disease.

Cutting edge: nociceptin stimulates neutrophil chemotaxis and recruitment: inhibition by aspirin-triggered-15-epi-lipoxin A4

The nociceptin receptor (Noci-R) is a G protein-coupled receptor present in neural tissues and its activation by nociceptin is involved in the processing of pain signals. Here, we report that Noci-R is present and functional on peripheral blood polymorphonuclear leukocytes (PMN). Human PMN express mRNA for Noci-R, its nucleotide sequence determined, and specific binding with [(125)I]-labeled nociceptin gave an apparent K(d) approximately 1.5 nM for this PMN opioid receptor. Nociceptin evoked PMN chemotaxis with maximal activity at 100 pM, without intracellular Ca(2+) mobilization. When injected in murine air pouches, nociceptin elicited leukocyte infiltration in a concentration-dependent fashion. Nociceptin-stimulated PMN infiltration was inhibited by treating mice with a synthetic analog of the aspirin-triggered lipid mediator 15-epi-lipoxin A(4). The present results identify nociceptin as a potent chemoattractant and provide a novel link between the neural and immune systems that are blocked by aspirin-triggered lipid mediators and may be relevant in neurogenic inflammation.

Factors modulating the epithelial response to toxicants in tracheobronchial airways

As one of the principal interfaces between the organism and the environment, the respiratory system is a target for a wide variety of toxicants and carcinogens. The cellular and architectural complexity of the respiratory system appears to play a major role in defining the focal nature of the pulmonary response to environmental stressors. This review will address the biological factors that modulate the response of one of the major target compartments within the respiratory system, the tracheobronchial airway tree. Individual airway segments respond uniquely to toxic stress and this response involves not only the target cell population, e.g. epithelium, but also other components of the airway wall suggesting a trophic interaction within all components of the airway wall in maintaining steady state and responding to injury. A number of biological factors modulate the nature of the response, including: (1) metabolic potential at specific sites for activation and detoxification; (2) the nature of the local inflammatory response; (3) age of the organism at the time of exposure; (4) gender of the exposed organism; (5) history of previous exposure; and (6) species and strain of the organism exposed.

Inhibition of nitric oxide synthesis by aminoguanidine increases intestinal damage in the acute phase of rat TNB-colitis

The role of nitric oxide (NO) in the pathophysiology of inflammatory bowel diseases (IBD) is controversially discussed. The aim of the present study was to investigate the role of NO inhibition in the acute phase of rat 2,4,6-trinitrobenzenesulphonic acid (TNB)-colitis. To inhibit NO synthesis we used aminoguanidine (AG) as a selective inhibitor of inducible nitric oxide synthase (iNOS). TNB-colitis was induced in rats with and without pretreatment with AG (200 mg kg-1 body weight in the drinking water). The severity of colitis was observed over a period of 7 days. On days 1 and 2, AG reduced concentrations of plasma nitrate and nitrite as well as of portal 6-keto-prostaglandin 1alpha. AG pretreatment increased colonic damage and inflammatory response, assessed by colonic myeloperoxidase and serum lactate dehydrogenase activity, macroscopic damage score, tumour necrosis factor-alpha concentration in stool and colonic glutathione content. The AG-treated group showed a higher and prolonged nuclear factor kappaB (NF-kappaB)/Rel binding activity in the colon. We conclude that NOS inhibition by AG is not beneficial in acute intestinal inflammation. With regard to appropriate therapeutic strategies, NF-kappaB/Rel activation might be a more suitable target.

Efficacy of disodium 4-[(tert-butylimino)methyl]benzene-1,3-disulfonate N-oxide (NXY-059), a free radical trapping agent, in a rat model of hemorrhagic stroke

Because free radical mechanisms may contribute to brain injury in hemorrhagic stroke, the effect of the free radical trapping agent disodium 4-[(tert-butylimino)methyl]benzene-1,3-disulfonate N-oxide (NXY-059) was investigated on outcome following intracerebral hemorrhage (ICH) in rat. ICH was induced in 20 adult rats by infusion of collagenase into the caudate-putamen. Thirty minutes later rats were treated with NXY-059 (50 mg/kg subcutaneous plus 8.8 mg/kg/h for 3 days subcutaneous delivered via implanted osmotic pumps) or saline (equivalent volumes). Magnetic resonance imaging 24 h after ICH confirmed that the hemorrhage was uniform in the two groups, and subsequent imaging at 7 and 42 days post-ICH showed that the hematoma resolved similarly in the two groups. Behavioral testing on days 1, 3, 7, 14, and 21 after ICH showed that rats treated with NXY-059 had significantly decreased neurological impairment at all times. Deficits in skilled forelimb use 4-5 weeks post-ICH, and in striatal function 6 weeks post-ICH, were not reduced by treatment with NXY-059. Treatment with NXY-059 significantly reduced the neutrophil infiltrate observed 48 h post-hemorrhage in the vicinity of the hematoma, and the number of TUNEL-positive cells 48 h post-hemorrhage at the hematoma margin. However, by 6 weeks there were no differences in neuronal densities in treated and control rats.

Interleukin 9 promotes influx and local maturation of eosinophils

The interleukin 9 (IL-9) pathway has recently been associated with the asthmatic phenotype including an eosinophilic tissue inflammation. The mechanism by which IL-9 affects eosinophils (eos) is not known. To investigate whether this cytokine has a direct activity on the development of eos and eosinophilic inflammation, a model of thioglycolate-induced peritoneal inflammation was used in IL-9 transgenic (TG5) and background strain (FVB) mice. In this model, a transient eosinophilic infiltration in the peritoneal cavity was observed in FVB mice 12 to 24 hours after thioglycolate injection that coincided with peak IL-5 and IL-9 release. In contrast, TG5 mice developed a massive eosinophilia that persisted at high levels (81% of total cells) even 72 hours after thioglycolate injection. Release of eosinophilic major basic protein (MBP), IL-4, and IL-5 to the peritoneal cavity of these mice was significantly increased when compared with the control FVB strain. To study the mechanism by which IL-9 exerts its effect on eos, bone marrow or peritoneal cells were cultured in the presence of IL-5, IL-9, or their combination in vitro. IL-5 alone was able to generate significant numbers of eos in TG5 but not FVB mice, whereas a combination of IL-5 and IL-9 induced marked eosinophilia in both strains indicating a synergism between these 2 cytokines. These data suggest that IL-9 may promote and sustain eosinophilic inflammation via IL-5-driven eos maturation of precursors.

Effect of FK-506 on inflammation and behavioral outcome following intracerebral hemorrhage in rat

Beginning 15 min after induction of intracerebral hemorrhage (ICH) by intrastriatal administration of collagenase, rats were treated intramuscularly with FK-506 (3 mg/kg) or with vehicle. Treatment was repeated daily for 7 days. MR imaging 1, 7, and 28 days post-ICH showed that treatment did not affect hematoma size or its subsequent resolution. Two days post-ICH, neutrophil infiltration around the hematoma was decreased in the FK-506-treated rats, as was the number of TUNEL-positive cells at the edge of the hematoma and in the peripheral region. The decreased inflammatory response was accompanied by functional improvement in the treated rats. The neurological deficit induced by the ICH (beam walking ability, postural reflex, spontaneous circling) was significantly decreased from 3 to 21 days post-ICH by treatment with FK-506. Skilled use of the forelimb ipsilateral to the ICH was improved and sensory neglect of the same limb was decreased 8-9 weeks post-ICH in rats treated with FK-506. However, neuronal loss assessed 9 weeks post-ICH was not different in the treated and untreated rats.

Inosine monophosphate and aspirin-triggered 15-epi-lipoxin A4 act in concert to regulate neutrophil trafficking: additive actions of two new endogenous anti-inflammatory mediators

Regulation of neutrophil (PMN) trafficking by soluble mediators is a critical component in the outcome of host defense, inflammation resolution, and neutrophil-mediated tissue injury. Elucidation of the endogenous mediators that protect tissues from excess leukocyte traffic and aberrant PMN activation that can lead to tissue damage and chronic inflammation is of considerable interest, especially the endogenous mechanisms of anti-inflammation. To this end, we recently uncovered two new classes of mediators: inosine monophosphate (IMP) and aspirin-triggered 15(R)-epimers of native lipoxin A(4). Here, we examined the combined actions of both classes of compounds in regulating key events in neutrophil trafficking. Neutrophil rolling in mouse microvessels was inhibited by both IMP or 5S,6R,15R-trihydroxy-7,9,13-trans-11-cis-eicosatetraenoic acid (15-epi-LXA(4)) in a concentration-dependent fashion. When combined, IMP (300 nM) and 15-epi-LX (10 nM) demonstrated additive inhibition of neutrophil rolling in microvessels. IMP and 15-epi-LX also significantly inhibited tumor necrosis factor-alpha (TNF-alpha)-induced neutrophil accumulation into the mouse air pouch in a dose-dependent manner. Again, the combination of low dose IMP (10 microg) and LX analog (5 microg) gave additive inhibition of neutrophil accumulation in this model. These results demonstrate the inhibition of neutrophil trafficking in two separate models by two different classes of small endogenous molecules. The additive inhibition by IMP and aspirin-triggered LX may represent key pathways that protect and resolve inflammatory responses that could be harnessed for treatment.

Inhibition of neutrophil elastase prevents cathelicidin activation and impairs clearance of bacteria from wounds

The host defense roles of neutrophil elastase in a porcine skin wound chamber model were explored. Analysis of wound fluid by acid-urea polyacrylamide gel electrophoresis, Western blot, and bacterial overlay confirmed that the neutrophil-derived protegrins constituted the major stable antimicrobial polypeptide in the wound fluid. The application to the wound of 0.10 and 0.25 mM N-methoxysuccinyl-alanine-alanine-proline-valine (AAPV) chloromethyl ketone, a specific neutrophil elastase inhibitor (NEI), blocked the proteolytic activation of protegrins and diminished the associated antimicrobial activity as detected by radial diffusion assay against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans or by bacterial gel overlay against S epidermidis and E coli. The application of the related cathepsin G inhibitor (CGI), benzyloxycarbonyl-glycine-leucine-phenylalanine (ZGLF) chloromethyl ketone, had no effect. In wound chambers that received 10(6) colony-forming unit (CFU)/mL of S epidermidis, the presence of NEI significantly decreased the 24-hour clearance of bacteria from the wound compared to wounds treated with CGI or solvent only. Neither inhibitor, at 0.10 or 0.25 mM concentration, affected leukocyte accumulation or degranulation in the wound chambers. The in vitro microbicidal decrement due to NEI was restored by an amount of the specific protegrin (PG-1), which was equivalent to the measured difference of protegrin between control and inhibited chambers. Administration of 1 microg/mL exogenous PG-1 4 hours after chamber preparation was sufficient to normalize in vivo antimicrobial activity. Although pharmacologic NEIs are promising candidates as anti-inflammatory drugs, they may impair host defense in part by inhibiting the activation of cathelicidins by neutrophil elastase.

Teprenone promotes the healing of acetic acid-induced chronic gastric ulcers in rats by inhibiting neutrophil infiltration and lipid peroxidation in ulcerated gastric tissues

Teprenone, an anti-ulcer drug, has been reported to promote the healing of acetic acid-induced chronic gastric ulcers in rats by stimulating gastric mucus synthesis and secretion. Recently, it has been implicated that neutrophil infiltration and lipid peroxidation in ulcerated gastric tissues have an inhibitory effect on the healing of acetic acid-induced chronic gastric ulcers in rats. Therefore, we attempted to clarify whether teprenone exerts a healing-promoting effect on acetic acid-induced chronic gastric ulcers through its inhibitory effect on neutrophil infiltration and lipid peroxidation in ulcerated gastric tissues. In rats with chronic gastric ulcers made by applying acetic acid to the stomach, gastric ulcer healing started later than 3 days after the acetic acid application. Gastric mucosal myeloperoxidase (MPO) activity, an index of tissue neutrophil infiltration, and lipid peroxide content were higher in the ulcerated region than in the intact region on the 8th, 15th, and 22nd day after the acetic acid application. Gastric mucosal non-protein SH content was lower in the ulcerated region than in the intact region on the 8th, 15th, and 22nd day after the acetic acid application, and gastric mucosal adherent mucus content was lower in the ulcerated region than in the intact region on the 8th and 15th day. Daily oral administration of teprenone (100 mg kg(-1)x 2) for 7 or 14 days, starting on the 8th day after the application of acetic acid to the stomach, enhanced the reduction of the ulcer area with attenuation of all these biochemical changes found in the ulcerated region. The teprenone administration caused a decrease in MPO activity and an increase in adherent mucus content in the gastric mucosa of the intact region. These results suggest that the healing-promoting effect of teprenone on acetic acid-induced chronic gastric ulcers in rats could be due not only to stimulation of gastric mucus secretion but also to inhibition of neutrophil infiltration and enhanced lipid peroxidation in the ulcerated gastric tissue.

Effects of dexamethasone and FK506 on Helicobacter pylori-induced gastritis and bacterial viability in Mongolian gerbils

FK506 and dexamethasone were used to investigate whether or not immunosuppression affects H. pylori colonization and gastric mucosal damage induced by Helicobacter pylori in Mongolian gerbils. Two weeks after H. pylori infection, FK506 and dexamethasone or vehicle alone were subcutaneously administered once daily for the following 2 weeks. FK506 or vehicle alone was administered subcutaneously once daily for 5 weeks (1 week before and 4 weeks after infection). In H. pylori-infected animals for 4 weeks, hemorrhagic erosions and inflammatory responses (neutrophil infiltration and lymphoid follicle formation) were induced in gastric mucosa at an incidence of 100%. Both FK506 and dexamethasone administered for 2 weeks markedly reduced such mucosal changes. In these animals, H. pylori viability in the stomach was significantly elevated. FK506 administered for 5 weeks also significantly inhibited the hemorrhagic erosions, edema and neutrophil infiltration in the stomach. H. pylori viability was slightly elevated as compared with the control. It was concluded that the host immune responses might play dual roles both by deteriorating gastritis induced by H. pylori and by protecting against H. pylori infection in its early stage.

Modulation of macrophage recruitment into wounds by monocyte chemoattractant protein-1

Previous studies suggest that normal wound repair requires the regulated production of monocyte and macrophage chemoattractants. The current study examines the role of monocyte chemoattractant protein-1 (MCP-1) in coordinating monocyte recruitment into sites of injury. MCP-1 protein was detected in both incisional and excisional murine wounds, with a peak concentration occurring slightly before maximum macrophage infiltration. Compared to wounds treated with control antibody, wounds treated with a neutralizing monoclonal anti-MCP-1 antibody contained significantly fewer macrophages (8.2 +/- 0.9 vs. 14 +/- 1.7 macrophages per high power field, p < 0.05). Conversely, the addition of recombinant MCP-1 to wounds resulted in a substantial increase in the number of macrophages (107% to 124% increase over untreated wounds, p < 0.01). Because macrophages promote wound healing, the effect of recombinant MCP-1 on the wound healing process was examined. Incisional wounds (n = 12) were either left untreated or treated with vehicle alone, 5 ng recombinant MCP-1 in vehicle, or 50 ng recombinant MCP-1 in vehicle. Wound disruption strength was determined on days 7, 14, 21, and 28 for each group. Wounds treated with MCP-1 exhibited a slight increase in wound disruption strength at nearly all time points but this increase did not reach statistical significance. Addition of 100 ng of MCP-1 to excisional wounds did not have any significant effect on wound reepithelialization. Taken together, the results show that MCP-1 is produced within wounds at physiologic concentrations, and is an important positive regulator of macrophage recruitment into sites of injury. Addition of exogenous MCP-1 to wounds of normal mice yields only modest enhancement of the repair process.

Antisense oligodeoxynucleotide inhibition of tumor necrosis factor-alpha expression is neuroprotective after intracerebral hemorrhage

BACKGROUND AND PURPOSE

Tumor necrosis factor-alpha (TNF-alpha) expression is increased in brain after cerebral ischemia, although little is known about its abundance and role in intracerebral hemorrhage (ICH). A TNF-alpha-specific antisense oligodeoxynucleotide (ORF4-PE) was used to study the extent to which TNF-alpha expression influenced neurobehavioral outcomes and brain damage in a collagenase-induced ICH model in rat.

METHODS

Male Sprague-Dawley rats were anesthetized, and ICH was induced by intrastriatal administration of heparin and collagenase. Immediately before or 3 hours after ICH induction, ORF4-PE was administered directly into the site of ICH. TNF-alpha mRNA and protein levels were measured by reverse transcriptase-polymerase chain reaction and immunoblot analyses. Cell death was measured by terminal deoxynucleotidyl transferase-mediated uridine 5'triphosphate-biotin nick end labeling (TUNEL). Neurobehavioral deficits were measured for 4 weeks after ICH.

RESULTS

ICH induction (n=6) elevated TNF-alpha mRNA and protein levels (P:<0.01) at 24 hours after the onset of injury compared with sham controls (n=6). Immunohistochemical labeling indicated that ICH was accompanied by elevated expression of TNF-alpha in neutrophils, macrophages, and microglia. Administration of ORF4-PE (2.0 nmol) directly into striatal parenchyma, 15 minutes before (n=4) or 3 hours after (n=6) ICH, decreased levels of TNF-alpha mRNA (P:<0.001) and protein (P:<0. 01) in the brain tissue surrounding the hematoma compared with animals treated with saline alone (n=6). Mean+/-SEM striatal cell death (cells per high-powered field) was also reduced in animals receiving ORF4-PE (34.1+/-5.0) compared with the saline-treated ICH group (80.3+/-7.50) (P:<0.001). ORF4-PE treatment improved neurobehavioral deficits observed at 24 hours (P:<0.001) after induction of ICH (n=6) compared with the untreated ICH group (n=6). This improvement was maintained at 28 days after hemorrhage induction (P:<0.001).

CONCLUSIONS

These results indicate a pathogenic role for TNF-alpha during ICH and demonstrate that reducing TNF-alpha expression using antisense oligodeoxynucleotides is neuroprotective.

Neutrophil accumulation induced by bacterial lipopolysaccharide: effects of dexamethasone and annexin 1

Annexin 1 (ANX-1) can reduce leucocyte migration in response to cytokines and chemokines in some rodent models of inflammation. However, its effectiveness against an inflammatory stimulus as strong as bacterial lipopolysaccharide (LPS) is unknown. Thus, we have examined whether ANX-1 can modulate LPS-induced neutrophil accumulation in the rat, as assessed by intravital microscopy and by myeloperoxidase (MPO) assay. The anti-inflammatory glucocorticoid, dexamethasone (DEX) was also studied for comparison. LPS superfusion induced adhesion of leucocytes to the endothelium and a subsequent increase in emigration from rat post-capillary venules over 2 h as assessed by intravital microscopy. Either ANX-1 or DEX was able to attenuate this adhesion and emigration of leucocytes. MPO activity in the lung, kidney and ileum was elevated after a 6-h exposure to LPS (intraperitoneal), indicating accumulation of neutrophils in these tissues. DEX attenuated the LPS-induced increase in MPO in the ileum but had no effect on MPO in the lungs or kidneys. This would suggest that the underlying mechanism by which neutrophils accumulate in the ileum, and more generally in the gastrointestinal compartment, is different from other vascular beds. ANX-1 had no effect on the LPS-induced increase in MPO activity in any of the tissues studied. Thus, from these data, ANX-1 appears to reduce leucocyte adhesion and emigration induced by a short-term (2 h), but not a longer (6 h) exposure to LPS.

Neutrophil, not macrophage, infiltration precedes neointimal thickening in balloon-injured arteries

Macrophages are abundant after stent-induced arterial injury. Inhibition of macrophage recruitment blocks neointimal growth in this model. In contrast, after superficial injury from balloon endothelial denudation, macrophages are sparse. However, many anti-inflammatory therapies remain effective against neointimal growth after balloon injury. To investigate further the role of leukocytes after injury, 41 New Zealand White rabbits underwent iliac artery balloon denudation. In 18, subcutaneous pumps were placed to deliver intravenous heparin (0.3 mg/kg per hour). Arteries were harvested at 6 hours and at 3, 7, and 14 days. In 8 animals, either M1/70 (a monoclonal antibody [mAb] against adhesion molecule Mac-1) or a nonspecific IgG was given (5 mg/kg IV bolus and then 1 mg/kg SC QOD), and arteries were harvested at 6 hours and 3 days. Computer-aided morphometry was performed as was immunohistochemistry to assess smooth muscle cell (SMC) proliferation (bromodeoxyuridine-positive cells), neutrophil content (RPN357, mAb against rabbit neutrophil/thymocyte), and macrophage content (RAM-11, mAb against rabbit macrophage). Heparin inhibited neointimal growth at 7 and 14 days (64% and 32.5% reduction, respectively; P:<0.05). Neutrophils were observed in the media early after balloon injury, and heparin and M1/70 inhibited this infiltration (82% and 83% reduction, respectively; P:<0.05 each) with a coincident inhibition of medial SMC proliferation at 3 days (49% and 84% reduction, respectively; P:<0.05 each). Macrophages were absent at all time points. Neutrophil, but not macrophage, infiltration occurs early after endothelial denudation. Inhibition of this process is associated with a reduction in medial SMC proliferation. These data suggest a central role for neutrophils in restenosis and help to explain prior reports of an inhibitory effect of anti-inflammatory therapies on neointimal growth after balloon injury.

Neutrophil migration stimulates rat intestinal epithelial cell cytokine expression during helminth infection

We are interested in understanding the role of epithelial cells during inflammation, and we previously reported that rat small intestinal epithelial cells express interleukin-1beta (IL-1beta) during infection by Trichinella spiralis. We now report that the epithelium also produces the potent neutrophil chemotactic factor, macrophage inflammatory protein-2 (MIP-2), and an IL-1 antagonist: the type II IL-1 receptor. Consequently we investigated the pattern of neutrophil infiltration into the infected intestine, which closely paralleled the epithelial cytokine expression. Speculating that neutrophil infiltration may provoke epithelial cytokine expression, neutrophil migration into the infected gut was reduced by depleting circulating cells through the use of a specific antibody, or by preventing migration through the use of a function-blocking anti-CD18 monoclonal antibody. Either treatment reduced the number of neutrophils recoverable from the small intestinal epithelium and was paralleled by reduced mRNA levels for epithelial cytokines. These results demonstrate that neutrophil infiltration of the small intestinal epithelium contributes to the stimulation of epithelial cell cytokines.

Interleukin-1beta -induced changes in blood-brain barrier permeability, apparent diffusion coefficient, and cerebral blood volume in the rat brain: a magnetic resonance study

The cytokine interleukin-1beta (IL-1beta) is implicated in a broad spectrum of CNS pathologies, in which it is thought to exacerbate neuronal loss. Here, the effects of injecting recombinant rat IL-1beta into the striatum of 3-week-old rats were followed noninvasively from 2 to 123 hr using magnetic resonance imaging and spectroscopy. Four hours after injection of IL-1beta (1 ng in 1 microliter), cerebral blood volume was significantly increased, the blood-brain barrier (BBB) became permeable to intravenously administered contrast agent between 4.5 and 5 hr, and the apparent diffusion coefficient (ADC) of brain water fell by 6 hr (5.42 +/- 0. 35 x 10(-4) mm(2)/sec treated, 7.35 +/- 0.77 x 10(-)(4) mm(2)/sec control; p < 0.001). At 24 hr the BBB was again intact, but the ADC, although partially recovered, remained depressed at both 24 and 123 hr (p < 0.03). Depleting the animals of neutrophils before IL-1beta injection prevented the BBB permeability at all time points, but the ADC was still depressed at 6 hr (6.64 +/- 0.34 x 10(-4) mm(2)/sec treated, 7.49 +/- 0.38 x 10(-4) mm(2)/sec control; p < 0.005). No changes were seen in brain metabolites using proton spectroscopy at 6 hr after IL-1beta. Intraparenchymal injection of IL-1beta caused a neutrophil-dependent transient increase in BBB permeability. The presence of neutrophils within the brain parenchyma significantly contributed to the IL-1beta-induced changes in cerebral blood volume and the ADC of brain water. However, IL-1beta apparently had a direct effect on the resident cell populations, which persisted well after all recruited leukocytes had disappeared. Thus the action of IL-1beta alone can give rise to magnetic resonance imaging-visible changes that are normally attributed to alterations to cellular homeostasis.

Intestinal toxicity of ketoprofen-trometamol vs its enantiomers in rat. Role of oxidative stress

OBJECTIVE

Gastrointestinal damage and bleeding are the major side effects of non-steroidal anti-inflammatory drugs (NSAID), however the mechanisms of this ulcerogenic action are not fully understood. It has recently been proposed that neutrophil-and oxygen radical-dependent microvascular injuries may be important prime events that lead to mucosal injury. In addition, other factors like bile flow, intact bacterial flora or feeding conditions may contribute to the formation of lesions. Ketoprofen is a NSAID that exists as a pair of R(-) and S (+) enantiomers; like other 2-arylpropionic acids, its anti-inflammatory effects resides almost exclusively in the S (+) isomer. The present study was undertaken to explore the role of oxidative stress in the pathogenesis of intestinal injury induced by oral administration of racemic ketoprofen and its enantiomers given as their water soluble tromethamine salts.

MATERIAL AND METHODS

Evaluation of intestinal damage and activities of oxidative stress related enzymes such as myeloperoxidase (MPO), xanthine-oxidase (XO) and superoxide dismutase (SOD) were studied in an experimental animal model using refed rats.

RESULTS

After the oral treatment followed by a refeeding period of 24 h, ketoprofen (100, 50, 25 mg/Kg b.w.) dose-dependently caused longitudinal ulcers on the mesenteric side of the middle and lower intestine lumen. The intestinal toxicity caused by S(+)-ketoprofen was significantly lower than the effect observed after racemate and R(-) enantiomer treatments (P <0.001), though the bioinversion of R(-)-ketoprofen to S(+)-enantiomer that occurs in the rat has to be considered. XO activity was unaffected by the studied drugs. Enhanced enteropathy by the racemate and its R (-)-enantiomer was correlated with a significant increase of MPO activity as an index of neutrophil infiltration, and a decrease in SOD activity (p<0.05 Vs control). S(+)-ketoprofen did not significantly change these parameters.

CONCLUSIONS

These results suggest that reactive oxygen metabolites can contribute significantly to the development of intestinal lesions, and that R(-)-ketoprofen present in racemic preparations can enhance the toxic intestinal effects of S (+)-enantiomer via modification of neutrophil migration and oxidative stress.

[Lesion caused by ischemia-reperfusion in lung transplantation]

OBJECTIVES

To assess the existence or not of a relation between the characteristics of lung donor and/or recipient and the development of ischemia-reperfusion injury (IRI). We also review the latest experimental findings on the biophysical conditions pf graft preservation.

PATIENTS AND METHOD

A retrospective study of 74 lung transplants performed in our hospital from 1993 to 1998. Donor and recipient screening and anesthetic and surgical techniques were performed following established protocols. Various degrees of IRI were determined according to hemodynamic and gasometric criteria. We analyzed the statistical relation between donor and recipient variables and IRI. Statistical significance was set at p < 0.05.

RESULTS

The incidence of IRI was 70.2% (52 cases), with 12 cases categorized as mild, 22 as moderate and 18 as severe. IRI was significantly related only to the start of extracorporeal circulation.

CONCLUSIONS

The development of IRI in lung transplantation is linked to such donor and/or recipient characteristics as the biophysical conditions of graft preservation. At present, greater prevention of this type of early dysfunction of the lung graft requires not only use of adequate screening criteria for donors and receivers but also adequate measures for graft preservation with the use of drugs and handling that have been shown to be effective.

A(2A) adenosine receptor-mediated inhibition of renal injury and neutrophil adhesion

We sought to determine the mechanisms responsible for the reduced renal tissue injury by agonists of A(2A) adenosine receptors (A(2A)-ARs) in models of ischemia-reperfusion (I/R) injury. DWH-146e, a selective A(2A)-AR agonist, was administered subcutaneously to Sprague-Dawley rats and C57BL/6 mice via osmotic minipumps, and animals were subjected to I/R. I/R led to an increase in plasma creatinine and kidney neutrophil infiltration. Infusion of DWH-146e at 10 ng. kg(-1). min(-1) produced a 70% reduction in plasma creatinine as well as a decrease in neutrophil density in outer medulla and cortex and myeloperoxidase activity in the reperfused kidney. Myeloperoxidase activity in kidney correlated with the degree of renal injury. P-selectin and intercellular adhesion molecule 1 (ICAM-1) immunoreactivity were most prominent in endothelial cells of peritubular capillaries and interlobular arteries of cortex and outer and inner medulla of vehicle-treated mice whose kidneys were subjected to I/R. DWH-146e treatment led to a pronounced decrease in P-selectin- and ICAM-1-like immunoreactivity. These data are consistent with our hypothesis that A(2A)-AR agonists limit I/R injury due to an inhibitory effect on neutrophil adhesion.

Inhibitory effects of MLDG-containing heterodimeric disintegrins reveal distinct structural requirements for interaction of the integrin alpha 9beta 1 with VCAM-1, tenascin-C, and osteopontin

The integrin alpha9beta1 is expressed on epithelial cells, smooth muscle cells, skeletal muscle, and neutrophils and recognizes at least three distinct ligands: vascular cell adhesion molecule 1 (VCAM-1), tenascin-C, and osteopontin. The alpha9 subunit is structurally similar to the integrin alpha4 subunit, and alpha9beta1 and alpha4beta1 both recognize VCAM-1 as a ligand. We therefore examined whether the disintegrin EC3, which we have recently shown specifically inhibits the binding of alpha4 integrins to ligands, would also be a functional inhibitor of alpha9beta1. EC3 and a novel heterodimeric disintegrin that we identified, EC6, both were potent inhibitors of alpha9beta1-mediated adhesion to VCAM-1 and of neutrophil migration across tumor necrosis factor-activated endothelial cells. A peptide containing a novel MLDG motif shared by both of these disintegrins also inhibited alpha9beta1- and alpha4beta1-mediated adhesion to VCAM-1. Surprisingly though, concentrations of EC3 that completely inhibited adhesion of alpha9-transfected cells to VCAM-1 had little or no effect on adhesion to either of the other alpha9beta1 ligands, osteopontin and tenascin-C. Furthermore, peptides AEIDGIEL and SVVYGLR, which we have previously shown inhibit binding of alpha9beta1-expressing cells to tenascin-C and osteopontin, respectively, had no effect on adhesion to VCAM-1. These data suggest that there are structurally distinct requirements for interactions of the alpha9beta1 integrin with VCAM-1 and the extracellular matrix ligands osteopontin and tenascin-C.

Tempol, a membrane-permeable radical scavenger, reduces dinitrobenzene sulfonic acid-induced colitis

Inflammatory bowel disease is characterized by oxidative and nitrosative stress, leukocyte infiltration, and up-regulation of intercellular adhesion molecule 1 (ICAM-1) expression in the colon. The aim of the present study was to examine the effects of tempol, a membrane-permeable radical scavenger, in rats subjected to experimental colitis. Colitis was induced in rats by intracolonic instillation of dinitrobenzene sulfonic acid. Rats experienced bloody diarrhea and significant loss of body weight. At 4 days after the administration of dinitrobenzene sulfonic acid, the colon injury comprised of large areas of mucosal necrosis. Neutrophil infiltration (measured as increase in myeloperoxidase activity in the mucosa) was associated with up-regulation of ICAM-1 and expression of P-selectin and high levels of malondialdehyde (an indicator of lipid peroxidation). Immunohistochemistry for nitrotyrosine and poly (ADP-ribose) synthetase showed an intense staining in the inflamed colon. Treatment of rats with tempol (15 mg/kg daily i.p.) significantly reduced the appearance of diarrhea and the loss in body weight. This was associated with a remarkable amelioration of the disruption of the colonic architecture as well as a significant reduction in the degree of both neutrophil infiltration and lipid peroxidation in the inflamed colon. Tempol also reduced the appearance of nitrotyrosine and poly (ADP-ribose) synthetase immunoreactivity in the colon as well as the up-regulation of ICAM-1 and P-selectin. The results of this study suggest that membrane-permeable radical scavengers, such as tempol, exert beneficial effects in experimental colitis and may, hence, be useful in the treatment of inflammatory bowel disease.

Anti-inflammatory effect of pirfenidone in the bleomycin-hamster model of lung inflammation

We have previously reported the antifibrotic effects of pirfenidone (PD) in the bleomycin (BL)-hamster model of lung fibrosis. Since the development of fibrosis is generally preceded by acute lung inflammation, the present study was conducted to find out if dietary intake of PD (0.5%) has any effects on BL-induced lung inflammation. In this regard, we evaluated the effects of PD on BL-induced increased pulmonary vascular permeability, increased influx of inflammatory cells and increased levels of TGF-beta in the bronchoalveolar lavage fluid (BALF). Hamsters were intratracheally (IT) instilled with saline (SA) or BL (5.5 units/kg/5 ml). The animals were fed the control diet (CD) or the same diet containing 0.5% PD 2 days prior to IT instillation and throughout the study. The bronchoalveolar lavage was carried out at different times after IT instillation. Lavage fluid was used for total and differential cell counts and BALF-supernatant for measurement of total protein and TGF-beta. IT instillation of BL caused significant increases in total cells, neutrophils, macrophages and lymphocytes and in the levels of total protein and TGF-beta in BALF from hamsters in the BL + CD groups as compared to the corresponding SA + CD control groups. In contrast, treatment with pirfenidone in general, suppressed the BL-induced increases in the levels of proteins and TGF-beta and in the influx of neutrophils, macrophages and lymphocytes in BALF at the early time points in BL + PD groups. Based on the data reported in this study, we conclude that the anti-inflammatory effects of pirfenidone as evident by suppressions of BL-induced increased pulmonary vascular permeability and increased influx of inflammatory cells in the lung contribute additionally to its inherent anti-fibrotic effect.

Garlic extract (allium sativum) reduces migration of neutrophils through endothelial cell monolayers

Leukocytes play an important role during inflammation. They migrate from intravascular spaces into tissues and attack micro-organisms. In a recent study, the inhibitory effects of the non-steroidal anti-inflammatory drug, ibuprofen, on leukocyte transmigration were demonstrated using an in vitro assay. Little is know about the cellular effects of garlic extracts (allium sativum). The aim of the current study was to investigate the influence of garlic extract on leukocyte migration through endothelial cell monolayers and thereby evaluate a possible role in inflammatory processes. Human umbilical endothelial cells were cultured on microporous membranes to make an endothelial cell monolayer (ECM). Freshly isolated neutrophils were used in a recently described migration assay. The amount of untreated neutrophils migrating through the untreated ECM was used as control and set at 100%. Neutrophils and/or ECM were pre-treated with garlic extract using moderate, as well as higher and lower concentrations. Moderate plasma concentrations garlic extract inhibited neutrophil migration through ECM significantly (64 +/- 5.8% SD; P < 0.05), when both cell types were treated, (a situation that may have clinical relevance). Treating either neutrophils or ECM alone showed significant reductions in migratory rate (neutrophils treated alone: 81 +/- 7.7% SD, p < 0.05; ECM alone: 70 +/- 6.7%, p < 0.05). Thus, garlic extract is identified as a potent inhibitor of leukocyte migration through endothelial cell monolayers. Treatment of both cell types has an additive effect. Endothelial cells seem to be more affected than neutrophils. Further investigations are necessary to understand the potential clinical consequences. During inflammation, neutrophils play an important role. They migrate rapidly from the vascular space into tissues to destroy invading micro-organisms. During migration through endothelial cell monolayers (ECM), neutrophils undergo morphologic changes from rounded, relatively smooth cells to elongated, ruffled cells with pseudopodia. Recently, the influence of the non-steroidal anti-inflammatory drug, ibuprofen, on leukocyte function was investigated using an in vitro double chamber migration assay that includes ECM. Garlic extract (allium sativum) is a widely used "over the counter" herbal preparation. The effect of garlic on lipid metabolism is well documented. Previous studies have examined the influence of the extract on leukocyte function, e.g. respiratory burst. The effect of garlic on thrombocyte aggregation has also been recently described as has an anti-fungal effect. To our knowledge, nothing is known about the effect of garlic leukocyte transmigration. Therefore, we aimed to examine the effects of garlic extract on leukocyte transmigration through ECM in an in-vitro cell co-culture system.

The local effect of PAF on leukocyte adherence to small bowel mesenteric venules following intra-abdominal contamination

We have previously demonstrated that intra-abdominal contamination increases neutrophil infiltration into the gastrointestinal tract. The purpose of our current study was twofold: 1) to determine if leukocyte adherence to the mesenteric microvasculature occurred by local peritoneal contamination or by systemic mechanisms; and 2) to assess the role of platelet activation factor (PAF) in this process. Rats underwent cecal ligation and puncture (CLP), and 4 h after the procedure we used intravital microscopy to visualize the mesenteric microcirculation. Cecal ligation and puncture increased leukocyte adherence (22.3+/-5.5 leukocytes/100 microm) vs. sham (2.3+/-0.9, P < 0.05). WEB-2086, a PAF receptor antagonist, prevented this increase (6.47+/-4.8, P < 0.05). To assess if leukocyte adherence was due to topical effects, we performed similar experiments with the small bowel exteriorized. In such cases, CLP did not increase leukocyte adherence (1.2+/-0.8 vs. 1.4+/-0.9). In addition, topical application of highly diluted fecal matter (1:1000) increased leukocyte adherence (4.8+/-1.2) vs. control (0.6+/-0.3, P < 0.05). Our study demonstrates that leukocyte adherence in the mesenteric microcirculation following intra-abdominal contamination is due to direct topical exposure to fecal matter, and it is mediated by PAF.

Changes in Helicobacter pylori-induced gastritis in the antrum and corpus during long-term acid-suppressive treatment in Japan

BACKGROUND

Several studies have shown that acid-suppressive therapy aggravates corpus gastritis in patients with Helicobacter pylori infection, promoting the development of atrophic gastritis.

AIM

To study the effects of long-term use of antisecretory agents on the H. pylori-positive gastric mucosa in Japan, a country with a high incidence of gastric cancer.

METHODS

A total of 141 H. pylori-positive patients who had peptic ulcers or reflux oesophagitis were treated for 3 years with either omeprazole (20 mg/day) alone (n=7) or with omeprazole for primary therapy (8 weeks), followed by famotidine (40 mg/day) for maintenance therapy (n=134). Endoscopy was performed before, during, and after treatment. Biopsy specimens were taken from the greater curvature of the antrum and corpus and were examined histologically.

RESULTS

The long-term use of famotidine after 8 weeks of treatment with omeprazole distinctly decreased H. pylori density and neutrophil infiltration in the antrum, but did not change H. pylori density in the corpus. The gastritis score increased in patients who had no, or only mild corpus gastritis before treatment (n=74), and significantly decreased in those who had moderate or severe gastritis before treatment (n=60). In four of the seven patients who received long-term treatment with omeprazole alone, neutrophil infiltration and H. pylori density decreased not only in the antrum but also in the corpus. There was no increase in intestinal metaplasia or mucosal atrophy as assessed endoscopically during follow-up.

CONCLUSION

Changes in corpus gastritis in response to acid-suppressive therapy depend on the severity of gastritis before treatment. Long-term use of acid-suppressive therapy apparently does not accelerate the development of atrophy or intestinal metaplasia in Japanese patients.

L-arginine attenuates trauma-hemorrhage-induced liver injury

OBJECTIVES

Liver injury is common after trauma-hemorrhage for which the underlying mechanism is not clear. Although administration of the essential amino acid L-arginine has been reported to restore the depressed cardiovascular functions and cell-mediated immune responses after trauma-hemorrhage, it remains unknown whether L-arginine protects against liver injury under those conditions.

DESIGN

A prospective, controlled animal study.

SETTING

A university research laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

Rats underwent sham operation or laparotomy and were bled to and maintained at a mean arterial blood pressure of 40 mm Hg until 40% of the maximum shed blood volume was returned in the form of lactated Ringer's solution. Hemorrhaged rats were then resuscitated with lactated Ringer's solution, four times the maximum shed blood volume over 1 hr. During resuscitation, animals received either 300 mg/kg of L-arginine or saline (vehicle) intravenously. At 3 and 5 hrs after resuscitation, rats were killed, blood was obtained, and the liver was fixed for histology (hematoxylin & eosin staining). Plasma glutathione S-transferase (a marker of liver damage), L-arginine, citrulline, and ornithine concentrations were assessed.

MEASUREMENTS AND MAIN RESULTS

The increased concentrations of plasma glutathione S-transferase observed in vehicle-treated hemorrhage animals were normalized with L-arginine treatment at 5 hrs after resuscitation. Moreover, the histology indicated that L-arginine prevented liver edema and neutrophil infiltration after trauma-hemorrhage. Plasma L-arginine and citrulline were increased in L-arginine-treated rats.

CONCLUSIONS

Because citrulline is a by-product of nitric oxide generation by nitric oxide synthase from L-arginine, this amino acid may be a useful adjunct for preventing hepatic injury after trauma-hemorrhage via endothelial derived nitric oxide production.

Thrombin and leukocyte recruitment in endotoxemia

Because thrombin has been implicated in sepsis, it has been proposed that antithrombin III (AT III) is beneficial due to its anticoagulatory and antiadhesive effects. Using intravital microscopy, we visualized leukocyte-endothelium interactions in postcapillary venules of the feline mesentery exposed to lipopolysaccharide (LPS). At a concentration of AT III that blocks leukocyte adhesion in postischemic mesentery, we found no role for thrombin in LPS-induced rolling, adhesion and emigration, or microvascular dysfunction. Furthermore, AT III did not attenuate leukocyte-endothelial interactions after tumor necrosis factor-alpha superfusion of the mesentery. In contrast, fucoidan, a selectin inhibitor, prevented almost all LPS-induced rolling and reduced adhesion, emigration, and microvascular dysfunction. In a model of endotoxemia, leukocyte recruitment into mesentery or lungs was unaffected by AT III. Finally, in a human cell system that mimics the flow conditions in vivo, human neutrophils rolled, adhered, and emigrated similar to the feline postcapillary microvessels, and AT III had no effect on leukocyte recruitment induced by LPS. If AT III has beneficial effects in endotoxemia, it is not due to a direct effect upon leukocyte rolling, adhesion, or emigration in postcapillary venules in vivo.

The flavonoid baicalin exhibits anti-inflammatory activity by binding to chemokines

Baicalin (BA) is a flavonoid compound purified from the medicinal plant Scutellaria baicalensis Georgi and has been reported to possess anti-inflammatory and anti-viral activities. In order to elucidate the mechanism(s) of action of BA, we tested whether BA could interfere with chemokines or chemokine receptors, which are critical mediators of inflammation and infection. We observed that BA inhibited the binding of a number of chemokines to human leukocytes or cells transfected to express specific chemokine receptors. This was associated with a reduced capacity of the chemokines to induce cell migration. Co-injection of BA with CXC chemokine interleukin-8 (IL-8) into rat skin significantly inhibited IL-8 elicited neutrophil infiltration. BA did not directly compete with chemokines for binding to receptors, but rather acted through its selective binding to chemokine ligands. This conclusion was supported by the fact that BA cross-linked to oxime resin bound chemokines of the CXC (stromal cell-derived factor (SDF)-1alpha, IL-8), CC (macrophage inflammatory protein (MIP)-1beta, monocyte chemotactic protein (MCP)-2), and C (lymphotactin (Ltn)) subfamilies. BA did not interact with CX3C chemokine fractalkine/neurotactin or other cytokines, such as TNF-alpha and IFN-gamma, indicating that its action is selective. These results suggest that one possible anti-inflammatory mechanism of BA is to bind a variety of chemokines and limit their biological function.

Effects of tempol, a membrane-permeable radical scavenger, in a gerbil model of brain injury

There is evidence that the excessive generation of reactive-oxygen radicals contributes to the brain injury associated with transient, cerebral ischemia. This study investigates the effects of tempol, a small, water-soluble molecule, that crosses biological membranes, on the brain injury caused by bilateral occlusion and reperfusion of both common carotid arteries in the gerbil (BCO). Treatment of gerbils with tempol (30 mg/kg i.p. at 30 min prior to reperfusion and at 1 and 6 h after the onset of reperfusion) reduced the formation of post-ischemic brain oedema. Tempol also attenuated the increase in the cerebral levels of malondialdehyde (MDA) and the hippocampal levels of myeloperoxidase (MPO) caused by cerebral ischemia and reperfusion. The immunohistochemical analysis of the hippocampal region of brains subjected to ischemia-reperfusion exhibited positive staining for nitrotyrosine (an indicator of the generation of peroxynitrite) and poly(ADP-ribose) synthetase (PARS) (an indicator of the activation of this nuclear enzyme secondary to single strand breaks in DNA). In gerbils subjected to BCO, which were treated with tempol, the degree of staining for nitrotyrosine and PARS was markedly reduced. Tempol increased survival and reduced the hyperactivity (secondary to the ischemia-induced neurodegeneration) caused by cerebral ischemia and reperfusion. The loss of neurons from the pyramidal layer of the CA1 region caused by ischemia and reperfusion was also attenuated by treatment of gerbils with tempol. This is the first evidence that the membrane-permeable, radical scavenger tempol reduces the cerebral injury caused by transient, cerebral ischemia in vivo.

Exaggerated response to endotoxin in mice lacking the Duffy antigen/receptor for chemokines (DARC)

Duffy antigen/receptor for chemokines (DARC) is a promiscuous receptor for chemokines that is required for Plasmodium vivax infection of erythroid cells. This receptor is expressed by subsets of endothelial, as well as erythroid cells. Selection for protection from malaria infection resulted in an erythroid-specific defect, suggesting that DARC may play a critical role in endothelial biology. Mice with targeted disruption of this gene were generated, and the function of DARC in inflammation was explored. RNA from spleens of homozygous mutant mice lacked DARC transcripts, which were abundant in wild-type (+/+) and heterozygote (+/-) mice. DARC(-/-) mice lacked developmental abnormalities and were healthy at 1 year. Whereas hematologic parameters were within normal ranges, erythrocytes from nullizygous mice lacked CXC and CC chemokine-binding activity. Challenge with lipopolysaccharide resulted in significantly increased inflammatory infiltrates in lung and liver of nullizygous mice. These results suggest that DARC modulates the intensity of inflammatory reactions as a sink for chemokines. (Blood. 2000;96:1681-1684)

Effects of the second-generation leukotriene B(4) receptor antagonist, LY293111Na, on leukocyte infiltration and collagen-induced arthritis in mice

The effects of the second-generation leukotriene B(4) receptor (LTB(4) receptor) antagonist, 2-[2-propyl-3-¿3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxy-phenoxy]-propo xy¿phenoxy]benzoic acid sodium salt (LY293111Na), on leukotriene B(4)-induced leukocyte infiltration and interleukin-1-accelerated collagen-induced arthritis in mice were studied. Neutrophil infiltration induced into an air pouch by leukotriene B(4) was dose-dependently inhibited by LY293111Na and strongly so by another LTB(4) receptor antagonist, 4-[5-¿4-(aminoiminomethyl)phenoxy¿pentoxy]-3-methoxy-N, N-bis(1-methylethyl) (Z)-2butenedioate (1:1) (CGS25019C). Both compounds significantly inhibited the increase of the arthritis index and the ankle bone destruction in interleukin-1-accelerated collagen-induced arthritis. Phenidone, a 5-lipoxygenase inhibitor, also inhibited interleukin-1-accelerated collagen-induced arthritis, while indomethacin and tenidap, cyclooxygenase inhibitors, had slight inhibitory effects. Injection of interleukin-1 elicited a marked increase of the leukotriene B(4) level in arthritic paws, while the prostaglandin E(2) level was slightly increased. These findings indicate clearly that leukotriene B(4) is an important mediator of interleukin-1-accelerated collagen-induced arthritis in mice. If this can be extrapolated to man, LTB(4) receptor antagonists might be useful for treatment of the acute progressive phase of human arthritis.

Type 4 phosphodiesterase inhibitors attenuate respiratory syncytial virus-induced airway hyper-responsiveness and lung eosinophilia

Viral respiratory infections are considered one of the triggers of exacerbations of asthma. In a model of virus-induced airway hyper-responsiveness (AHR), mice infected with human respiratory syncytial virus (RSV) were shown to develop AHR accompanied by lung eosinophilia. Inhibitors of cyclic nucleotide phosphodiesterase (PDE) have been shown to affect airway responsiveness and pulmonary allergic inflammation. In this study, we assessed the effects of type 4 PDE (PDE4) inhibitors on AHR following RSV infection and compared them with a PDE3 inhibitor. In mice infected by intranasal inoculation of RSV, treatment with the PDE4 inhibitor rolipram or Ro-20-1724 reduced both AHR and the eosinophil infiltration of the airways. In contrast, the PDE3 inhibitor, milrinone, did not influence airway responsiveness or eosinophilic inflammation. These results demonstrate that PDE4 inhibitors can modulate RSV-induced AHR and lung eosinophilia and indicate that they have a potential role in treating exacerbations of asthma triggered by viral infection.

Chemoprevention of biliary carcinogenesis in syrian hamsters by the novel carboxamide derivative IS-741 after initiation with N-nitrosobis(2-oxopropyl)amine (BOP)

To elucidate the possible inhibitory effect of a novel carboxamide derivative (IS-741) on biliary carcinogenesis, Syrian hamsters were subjected to cholecystoduodenostomy and ligation of the distal end of the common duct, and then given a regular diet (group I) or a diet containing 200 p.p.m. of IS-741 (group II). All hamsters were subcutaneously injected with N-nitrosobis(2-oxopropyl)amine until 10 weeks after surgery, and continued to feed on their respective dietary regimen until termination of the experiment at 16 weeks after surgery. Biliary adenocarcinomas were evaluated histologically. Non-cancerous and cancerous hepatobiliary tract tissues were analyzed for phospholipase A(2) (PLA(2)) activity, myeloperoxidase (MPO) activity, and the concentrations of prostaglandin (PG), i.e., prostaglandin E(2), 6-ketoprostaglandin F(1)alpha and thromboxane B(2). IS-741 significantly inhibited the development and multiplicity of hepatobiliary adenocarcinomas and reduced the proliferating cell nuclear antigen labeling indices in non-cancerous hepatobiliary tissues, compared with group I. The anti-cancerous effect of IS-741 was associated with a significant inhibition of PLA(2) and MPO levels in non-cancerous tissues of the extrahepatic biliary tract and the liver, and in cancerous tissue of the liver. Furthermore, IS-741 reduced the production of PGs in non-cancerous hepatobiliary tissues, compared with group I. Although the precise mechanism of action of IS-741 in preventing biliary tumorigenesis remains to be elucidated, it is likely to be related to modulation of arachidonic acid metabolism and/or suppression of neutrophil accumulation.