Stromal interleukin-1 expression in the cornea after haze-associated injury

The purpose of this study was to determine whether myofibroblasts or other cells in the stroma in the cornea produce interleukin (IL)-1 alpha or IL-1 beta that could modulate myofibroblast viability in corneas with haze after photorefractive keratectomy (PRK). Twenty-four female rabbits had haze-generating PRK for 9 diopters of myopia and were sacrificed at 1 week, 2 weeks, 3 weeks or 4 weeks after surgery. Corneal rims were removed, frozen in OCT at -80 degrees C, and analyzed by immunocytochemistry using primary antibodies to IL-1 alpha, IL-1 beta and alpha smooth muscle actin (SMA). Double immunostaining was performed for the co-localization of SMA with IL-1 alpha or IL-1 beta. Central dense haze and peripheral slight haze regions of each cornea were analyzed. SMA+ cells that expressed IL-1 alpha protein were detected in both regions of the corneas at most time points following PRK. However, in the haze region at the 1,3 and 4 week time points, significantly more (p < 0.01) SMA cells did not express IL-1 alpha. Also, in the haze region at all three time points, significantly more (p < 0.01) SMA- cells than SMA+ cells expressed interleukin-1 alpha protein. IL-1 beta expression patterns in SMA+ and SMA- stromal cells was similar to that of IL-1 alpha after PRK. Previous studies have demonstrated that IL-1 alpha or IL-1 beta triggers myofibroblast apoptosis in vitro, depending on the available concentration of apoptosis-suppressive TGFO. This study demonstrates that SMA- cells such as corneal fibroblasts, keratocytes, or inflammatory cells may produce IL-1 alpha and/or IL-1 beta that could act in paracrine fashion to regulate myofibroblast apoptosis-especially in the region where there is haze in the cornea after PRK was performed and SMA+ myofibroblasts are present at higher density. However, some SMA+ myofibroblasts themselves produce IL-1 alpha and/or IL-1 beta, suggesting that myofibroblast viability could also be regulated via autocrine mechanisms. (C) 2010 Elsevier Ltd. All rights reserved.

COMBINATION OFGENERAL AND SPECIFICWARM-UPS IMPROVES LEG-PRESS ONE REPETITION MAXIMUM COMPARED WITH SPECIFIC WARM-UP IN TRAINED INDIVIDUALS

Abad, CCC, Prado, ML, Ugrinowitsch, C, Tricoli, V, and Barroso, R. Combination of general and specific warm-ups improves leg-press one repetition maximum compared with specific warm-up in trained individuals. J Strength Cond Res 25(8): 2242-2245, 2011-Accurate assessment of muscular strength is critical for exercise prescription and functional evaluation. The warm-up protocol may affect the precision of the 1 repetition maximum (1RM) test. Testing guidelines recommend performing both general and specific warm-ups before strength tests. The general warm-up intends to raise muscle temperature, whereas the specific warm-up aims to increase neuromuscular activation. Although there is scientific evidence for performing the specific warm-up, the effects of general warm-up on strength tests are still unclear. The purpose of this study was to investigate whether the combination of a general with a specific warm-up (G + SWU) protocol would improve leg press 1RM values compared with a specific warm-up (SWU) protocol. Thirteen participants were tested for leg-press 1RM under 2 warm-up conditions. In the first condition, participants performed the SWU only, which was composed of 1 set of 8 repetitions at approximately 50% of the estimated 1RM followed by another set of 3 repetitions at 70% of the estimated 1RM. In the second condition (G + SWU), participants performed the 1RM test after a 20-minute general warm-up on a stationary bicycle at 60% of HRmax and the same specific warm-up as in the SWU. Values of 1RM in SWU and in G + SWU were compared by a paired t-test, and significance level was set at p <= 0.05. Strength values were on average 8.4% (p = 0.002) higher in the G + SWU compared with the SWU. These results suggest that the G + SWU induced temperature-dependent neuromuscular adjustments that increased muscle force production capacity. Therefore, these results support the recommendations of the testing guidelines to perform a moderate intensity general warm-up in addition to the specific warm-up before maximum strength assessments.

ELECTROMYOGRAPHIC AMPLITUDE RATIO OF SERRATUS ANTERIOR AND UPPER TRAPEZIUS MUSCLES DURING MODIFIED PUSH-UPS AND BENCH PRESS EXERCISES

Imbalance and weakness of the serratus anterior and upper trapezius force couple have been described in patients with shoulder dysfunction. There is interest in identifying exercises that selectively activate these muscles and including it in rehabilitation protocols. This study aims to verify the UT/SA electromyographic (EMG) amplitude ratio, performed in different upper limb exercises and on two bases of support. Twelve healthy men were tested (average age = 22.8 +/- 3.1 years), and surface EMG was recorded from the upper trapezius and serratus anterior using single differential surface electrodes. Volunteers performed isometric contractions over a stable base of support and on a Swiss ball during the wall push-up (WP), bench press (BP), and push-up (PU) exercises. All SEMG data are reported as a percentage of root mean square or integral of linear envelope from the maximal value obtained in one of three maximal voluntary contractions for each muscle studied. A linear mixed-effect model was performed to compare UT/SA ratio values. The WP, BP, and PU exercises showed UT/SA ratio mean +/- SD values of 0.69 +/- 0.72, 0.14 +/- 0.12, and 0.39 +/- 0.37 for stable surfaces, respectively, whereas for unstable surfaces, the values were 0.73 +/- 0.67, 0.43 +/- 0.39, and 0.32 +/- 0.30. The results demonstrate that UT/SA ratio was influenced by the exercises and by the upper limb base of support. The practical application is to show that BP on a stable surface is the exercise preferred over WP and PU on either surfaces for serratus anterior muscle training in patients with imbalance between the UT/SA force couple or serratus anterior weakness.

Activation of Selected Shoulder Muscles During Unilateral Wall and Bench Press Tasks Under Submaximal Isometric Effort

STUDY DESIGN: Controlled laboratory study. OBJECTIVE: To assess the activation of 7 shoulder muscles under 2 closed kinetic chain (CKC) tasks for the upper extremity using submaximal isometric effort, thus providing relative quantification of muscular isometric effort for these muscles across the CKC exercises, which may be applied to rehabilitation protocols for individuals with shoulder weakness. BACKGROUND: CKC exercises favor joint congruence, reduce shear load, and promote joint dynamic stability. Additionally, knowledge about glenohumeral and periscapular muscle activity elicited during CKC exercises may help clinicians to design protocols for shoulder rehabilitation. METHODS: Using surface electromyography, activation level was measured across 7 shoulder muscles in 20 healthy males, during the performance of a submaximal isometric wall press and bench press. Signals were normalized to the maximal voluntary isometric contraction, and, using paired t tests, data were analyzed between the exercises for each muscle. RESULTS: Compared to the wall press, the bench press elicited higher activity for most muscles, except for the upper trapezius. Levels of activity were usually low but were above 20% maximal voluntary isometric contraction for the serratus anterior on both tasks, and for the long head triceps brachii on the bench press. CONCLUSIONS: Both the bench press and wall press, as performed in this study, led to relatively low EMG activation levels for the muscles measured and may be considered for use in the early phases of rehabilitation. J Ort hop Sports Phys Ther 2011;41(7):520-525, Epub 2 February 2011. doi:10.2519/jospt.2011.3418

Fatty acid synthesis and generation of glycerol-3-phosphate in brown adipose tissue from rats fed a cafeteria diet

In vivo fatty acid synthesis and the pathways of glycerol-3-phosphate (G3P) production were investigated in brown adipose tissue (BAT) from rats fed a cafeteria diet for 3 weeks. In spite of BAT activation, the diet promoted an increase in the carcass fatty acid content. Plasma insulin levels were markedly increased in cafeteria diet-fed rats. Two insulin-sensitive processes, in vivo fatty acid synthesis and in vivo glucose uptake (which was used to evaluate G3P generation via glycolysis) were increased in BAT from rats fed the cafeteria diet. Direct glycerol phosphorylation, evaluated by glycerokinase (GyK) activity and incorporation of [U-(14)C]glycerol into triacylglycerol (TAG)-glycerol, was also markedly increased in BAT from these rats. In contrast, the cafeteria diet induced a marked reduction of BAT glyceroneogenesis, evaluated by phosphoenolpyruvate carboxykinase-C activity and incorporation of [1-(14)C]pyruvate into TAG-glycerol. BAT denervation resulted in an approximately 50% reduction of GyK activity, but did not significantly affect BAT in vivo fatty acid synthesis, in vivo glucose uptake, or glyceroneogenesis. The data suggest that the supply of G3P for BAT TAG synthesis can be adjusted independently from the sympathetic nervous system and solely by reciprocal changes in the generation of G3P via glycolysis and via glyceroneogenesis, with no participation of direct phosphorylation of glycerol by GyK.

Sildenafil inhibits duodenal contractility via activation of the NO-K+ channel pathway

Phosphodiesterase type-5 (PDE5) specifically cleaves cyclic guanosine monophosphate (cGMP), a key intracellular secondary messenger. The PDE5 inhibitor sildenafil is a well-known vasodilator that also has gastrointestinal myorelaxant properties. In the present study, we further investigated sildenafil-induced myorelaxation in rat isolated duodenum, assessing its interaction with nitric oxide (NO) synthase and K+ channel opening. The spontaneous contractions of duodenal strips were reversibly inhibited by sildenafil (0.1-300 mu M) in a concentration-dependent manner [mean (95% confidence interval); EC50 = 6.8 (2.7-17.3) mu M]. The sildenafil-induced myorelaxation was significantly decreased by the NO synthase inhibitor N-nitro-L-arginine methyl ester [increasing the EC50 value to 41.9 (26.1-67.3) mu M]. Sodium nitroprusside or forskolin pretreatments enhanced the sildenafil-induced myorelaxation. In isolated strips pretreated with BaCl2 (0.2 mM), 4-aminopyridine (4-AP, 3 mM), or glybenclamide (1 mu M), the sildenafil-induced EC50 value was significantly increased to 32.8 (19.1-56.4), 27.1 (15.2-48.3) and 20.1 (16.4-24.7) mu M, respectively. Minoxidil (50 mu M) or diazoxide (100 mu M) also significantly attenuated the sildenafil-induced potency. In conclusion, the NO synthase/cyclic nucleotide pathway activation is involved in sildenafil-induced inhibition of spontaneous duodenal contractions. Its pharmacological action seems to be influenced by K+ channel opening, especially the voltage-sensitive ones, being inhibited by 4-AP and K-ATP channels, sensitive to glybenclamide.

P2X(7) receptor activation amplifies lipopolysaccharide-induced vascular hyporeactivity via interleukin-1 beta release

Lipopolysaccharide (LPS) stimulates cytoplasmic accumulation of pro-interleukin (IL)-1 beta. Activation of P2X(7) receptors stimulates conversion of pro-IL-1 beta into mature IL-1 beta, which is then secreted. Because both LPS (in vivo) and IL-1 beta (in vitro) decrease vascular reactivity to contractile agents, we hypothesized the following: 1) P2X(7) receptor activation contributes to LPS-induced vascular hyporeactivity, and 2) IL-1 beta mediates this change. Thoracic aortas were obtained from 12-week-old male C57BL/6 mice. The aortic rings were incubated for 24 h in Dulbecco`s modified Eagle`s medium, LPS, benzoylbenzoyl-ATP (BzATP; P2X(7) receptor agonist), LPS plus BzATP, oxidized ATP (oATP; P2X(7) receptor antagonist), or oATP plus LPS plus BzATP. After the treatment, the rings were either mounted in a myograph for evaluation of contractile activity or homogenized for IL-1 beta and inducible nitric-oxide synthase (iNOS) protein measurement. In endothelium-intact aortic rings, phenylephrine (PE)-induced contractions were not altered by incubation with LPS or BzATP, but they significantly decreased in aortic rings incubated with LPS plus BzATP. Treatment with oATP or IL-1ra (IL-1 beta receptor antagonist) reversed LPS plus BzATP-induced hyporeactivity to PE. In the presence of N(G)-nitro-L-arginine methyl ester or N-([3-(aminomethyl) phenyl] methyl) ethanimidamide (selective iNOS inhibitor), the vascular hyporeactivity induced by LPS plus BzATP on PE responses was not observed. BzATP augmented LPS-induced IL-1 beta release and iNOS protein expression, and these effects were also inhibited by oATP. Moreover, incubation of endothelium-intact aortic rings with IL-1 beta induced iNOS protein expression. Thus, activation of P2X 7 receptor amplifies LPS-induced hyporeactivity in mouse endothelium-intact aorta, which is associated with IL-1 beta-mediated release of nitric oxide by iNOS.

Phlebotomine salivas inhibit immune inflammation-induced neutrophil migration via an autocrine DC-derived PGE(2)/IL-10 sequential pathway

In the present study, we investigated whether saliva from Phlebotomus papatasi and Phlebotomus duboscqi inhibited antigen-induced neutrophil migration and the mechanisms involved in these effects. The pretreatment of immunized mice with salivary gland extracts (SGE) of both phlebotomines inhibited OVA challenge-induced neutrophil migration and release of the neutrophil chemotactic mediators, MIP-1 alpha, TNF-alpha, and leukotriene B-4 (LTB4). Furthermore, SGE treatment enhanced the production of anti-inflammatory mediators, IL-10 and PGE(2). SGE treatments failed to inhibit neutrophil migration and MIP-1 alpha and LTB4 production in IL-10(-/-) mice, also failing in mice treated with nonselective (indomethacin) or selective (rofecoxibe) cyclooxygenase (COX) inhibitors. COX inhibition resulted in diminished SGE-induced IL-10 production, and PGE(2) release triggered by SGE remained increased in IL-10(-/-) mice, suggesting that prostanoids are acting through an IL-10-dependent mechanism. SGE treatments in vivo reduced the OVA-induced lymphoproliferation of spleen-derived cells. Further, the in vitro incubation of bone marrow-derived dendritic cells (DC) with SGE inhibited the proliferation of CD4(+) T cells from OVA-immunized mice, which was reversed by indomethacin and anti-IL-10 antibody treatments. Supporting these results, SGE induced the production of PGE(2) and IL-10 by DC, which were blocked by COX inhibition. These effects were associated with the reduction of DC-membrane expression of MHC-II and CD86 by SGE treatment. Altogether, the results showed that Phlebotomine saliva inhibits immune inflammation-induced neutrophil migration by an autocrine DC sequential production of PGE(2)/IL-10, suggesting that the saliva constituents might be promising therapeutic molecules to target immune inflammatory diseases.

DOCA-salt treatment enhances responses to endothelin-1 in murine corpus cavernosurn

The penis is kept in the flaccid state mainly via a tonic activity of norepinephrine and endothelins (ETs). ET-1 is important in salt-sensitive forms of hypertension. We hypothesized that cavernosal responses to ET-1 are enhanced in deoxycorticosterone acetate (DOCA)-salt mice and that blockade of ETA receptors prevents abnormal responses of the corpus cavernosum in DOCA-salt hypertension. Male C57BL/6 mice were unilaterally nephrectomized and treated for 5 weeks with both DOCA and water containing 1% NaCl and 0.2% KCl. Control mice were uninephrectomized and received tap water with no added salt. Animals received either the ETA antagonist atrasentan (5 mg.day(-1).kg(-1) body weight) or vehicle. DOCA-salt mice displayed increased systolic blood pressure (SBP), and treatment with atrasentan decreased SBP in DOCA-salt mice. Contractile responses in cavernosal strips from DOCA-salt mice were enhanced by ET-1, phenylephrine, and electrical field stimulation (EFS) of adrenergic nerves, whereas relaxations were not altered by IRL-1620 (an ETB agonist), acetylcholine, sodium nitroprusside, and EFS of nonadrenergic noncholinergic nerves. PD59089 (an ERK1/2 inhibitor), but not Y-27632 (a Rho-kinase inhibitor), abolished enhanced contractions to ET-1 in cavernosum from DOCA-salt mice. Treatment of DOCA-salt mice with atrasentan did not normalize cavernosal responses. In summary, DOCA-salt treatment in mice enhances cavernosal reactivity to contractile, but not to relaxant, stimuli, via ET-1/ETA receptor-independent mechanisms.

Granulocyte-Colony Stimulating Factor (G-CSF) induces mechanical hyperalgesia via spinal activation of MAP kinases and PI(3)K in mice

Granulocyte-colony stimulating factor (G-CSF) is a current pharmacological approach to increase peripheral neutrophil counts after anti-tumor therapies. Pain is most relevant side effect of G-CSF in healthy volunteers and cancer patients. Therefore, the mechanisms of G-CSF-induced hyperalgesia were investigated focusing on the role of spinal mitogen-activated protein (MAP) kinases ERK (extracellular signal-regulated kinase). JNK (Jun N-terminal Kinase) and p38, and PI(3)K (phosphatidylinositol 3-kinase). G-CSF induced dose (30-300 ng/paw)-dependent mechanical hyperalgesia, which was inhibited by local post-treatment with morphine. This effect of morphine was reversed by naloxone (opioid receptor antagonist). Furthermore, G-CSF-induced hyperalgesia was inhibited in a dose-dependent manner by intrathecal pre-treatment with ERK (PD98059), JNK (SB600125), p38 (SB202190) or PI(3)K (wortmanin) inhibitors. The co-treatment with MAP kinase and PI(3)K inhibitors, at doses that were ineffective as single treatment, significantly inhibited G-CSF-induced hyperalgesia. Concluding, in addition to systemic opioids, peripheral opioids as well as spinal treatment with MAP kinases and PI(3)K inhibitors also reduce G-CSF-induced pain. (C) 2011 Elsevier Inc. All rights reserved.

Peroxisome proliferator-activated receptor-gamma ligand, 15-deoxy-Delta A(12,14)-prostaglandin J(2), reduces neutrophil migration via a nitric oxide pathway

Ligands for peroxisome proliferator-activated receptor gamma (PPAR-gamma), such as 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) have been implicated as a new class of anti-inflammatory compounds with possible clinical applications. Based on this concept, this investigation was designed to determine the effect of 15d-PGJ(2)-mediated activation of PPAR-gamma ligand on neutrophil migration after an inflammatory stimulus and clarify the underlying molecular mechanisms using a mouse model of peritonitis. Our results demonstrated that 15d-PGJ(2) administration decreases leukocyte rolling and adhesion to the inflammated mesenteric tissues by a mechanism dependent on NO. Specifically, pharmacological inhibitors of NO synthase remarkably abrogated the 15d-PGJ(2)-mediated suppression of neutrophil migration to the inflammatory site. Moreover, inducible NOS(-/-) mice were not susceptible to 15d-PGJ(2)-mediated suppression of neutrophil migration to the inflammatory sites when compared with their wild type. In addition, 15d-PGJ(2)-mediated suppression of neutrophil migration appeared to be independent of the production of cytokines and chemokines, since their production were not significantly affected in the carrageenan-injected peritoneal cavities. Finally, up-regulation of carrageenan-triggered ICAM-I expression in the mesenteric microcirculation vessels was abrogated by pretreatment of wild-type mice with 15d-PGJ(2), whereas 15d-PGJ(2) inhibited F-actin rearrangement process in neutrophils. Taken together these findings demonstrated that 15d-PGJ(2) suppresses inflammation-initiated neutrophil migration in a mechanism dependent on NO production in mesenteric tissues.

Hydrogen Sulfide Improves Neutrophil Migration and Survival in Sepsis via K(ATP)(+) Channel Activation

Rationale Recovering the neutrophil migration to the infectious focus improves survival in severe sepsis. Recently, we demonstrated that the cystathionine gamma-lyase (CSE)/hydrogen sulfide (H(2)S) pathway increased neutrophil recruitment to inflammatory focus during sterile inflammation. Objectives: To evaluate if H(2)S administration increases neutrophil migration to infectious focus and survival of mice. Methods. Sepsis was induced by cecal ligation and puncture (CLP) Measurements and Main Results. The pretreatments of mice with H2S donors (NaHS or Lawesson`s reagent) improved leukocyte rolling/adhesion in the mesenteric microcirculation as well as neutrophil migration. Consequently, bacteremia levels were reduced, hypotension and lung lesions were prevented, and the survival rate increased from approximately 13% to approximately 80% Even when treatment was delayed (6 h after CLP), a highly significant reduction in mortality compared with untreated mice was observed Moreover, H(2)S pretreatment prevented the down-regulation of CXCR2 and L-selectin and the up-regulation of CD11b and G protein-coupled receptor kinase 2 in neutrophils during sepsis. H(2)S also prevented the reduction of intercellular adhesion molecule-1 expression in the endothelium of the mesenteric microcirculation in severe sepsis Confirming the critical role of H(2)S on sepsis outcome, pretreatment with dl-propargylglycine (a CSE inhibitor) inhibited neutrophil migration to the infectious focus, enhanced lung lesions, and induced high mortality in mice subjected to nonsevere sepsis (from 0 to similar to 80%). The beneficial effects of H(2)S were blocked by glibenclamide (a ATP-dependent K(+) channel blocker). Conclusions: These results showed that H(2)S restores neutrophil migration to the infectious focus and improves survival outcome in severe sepsis by an ATP-dependent K(+) channel-dependent mechanism.

Inhibition of spontaneous neurotransmission in the nucleus of solitary tract of the rat by the cannabinoid agonist WIN 55212-2 is not via CB1 or CB2 receptors

Cannabinoids have been shown to modulate central autonomic regulation and baroreflex control of blood pressure. Both CB1 and CB2 cannabinoid receptors have been described in the nucleus tractus solitarius (NTS), which receives direct afferent projections of cardiovascular reflexes. in the present study we evaluated the effects of WIN 55212-2 (WIN), a cannabinoid agonist, on fast neurotransmission in the NTS. We recorded spontaneous post-synaptic currents using the whole-cell configuration in NTS cells in brainstem slices from young rats (25-30 days old). Application of 5 mu M WIN inhibited the frequency of both glutamatergic and GABAergic sPSCs, without affecting their amplitudes. Effects of WIN were not blocked by application of the CB1 antagonist AM251, the CB2 antagonist AM630 or the varmiloid receptor TRPV1 antagonist AMG9810, suggesting that the effect of WIN is via a non-CB1 non-CB2 receptor. Neither the CB1/CB2 agonist HU210 nor the CB1 agonist ACPA affected the frequency of sPSCs. We conclude WIN inhibits the neurotransmission in the NTS of young rats via a receptor distinct from CB1 or CB2. (c) 2008 Elsevier B.V. All rights reserved.

Modulation of effective connectivity during emotional processing by Delta(9)-tetrahydrocannabinol and cannabidiol

Cannabis sativa, the most widely used illicit drug, has profound effects on levels of anxiety in animals and humans. Although recent studies have helped provide a better understanding of the neurofunctional correlates of these effects, indicating the involvement of the amygdala and cingulate cortex, their reciprocal influence is still mostly unknown. In this study dynamic causal modelling (DCM) and Bayesian model selection (BMS) were used to explore the effects of pure compounds of C. sativa [600 mg of cannabidiol (CBD) and 10 mg Delta(9)-tetrahydrocannabinol (Delta(9)-THC)] on prefrontal-subcortical effective connectivity in 15 healthy subjects who underwent a double-blind randomized, placebo-controlled fMRI paradigm while viewing faces which elicited different levels of anxiety. In the placebo condition, BMS identified a model with driving inputs entering via the anterior cingulate and forward intrinsic connectivity between the amygdala and the anterior cingulate as the best fit. CBD but not Delta(9)-THC disrupted forward connectivity between these regions during the neural response to fearful faces. This is the first study to show that the disruption of prefrontal-subocrtical connectivity by CBD may represent neurophysiological correlates of its anxiolytic properties.

Reduction of ICAM-1 expression by carbon monoxide via soluble guanylate cyclase activation accounts for modulation of neutrophil migration

Previously, it was demonstrated that the heme/heme oxygenase (HO)/carbon monoxide (CO) pathway inhibits neutrophil recruitment during the inflammatory response. Herein, we addressed whether the inhibitory effect of the HO pathway on neutrophil adhesion and migration involves the reduction of intracellular adhesion molecule type (ICAM)-1 and beta(2)-integrin expression. Mice pretreated with a specific inhibitor of inducible HO (HO-1), zinc protoporphyrin (ZnPP) IX, exhibit enhanced neutrophil adhesion and migration induced by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS). These findings are associated with an increase in ICAM-1 expression on mesentery venular endothelium. In accordance, HO-1 inhibition did not enhance LPS-induced neutrophil migration and adhesion in ICAM-1-deficient mice. Furthermore, the treatment with a CO donor (dimanganese decacarbonyl, DMDC) that inhibits adhesion and migration of the neutrophils, reduced LPS-induced ICAM-1 expression. Moreover, neither DMDC nor ZnPP IX treatments changed LPS-induced beta(2)-integrin expression on neutrophils. The effect of CO on ICAM-1 expression seems to be dependent on soluble guanylate cyclase (sGC) activation, since 1H-(1,2,4)oxadiazolo (4,3-a)quinoxalin-1-one (sGC inhibitor) prevented the observed CO effects. Finally, it was observed that the nitric oxide (NO) anti-inflammatory effects on ICAM-1 expression appear to be indirectly mediated by HO-1 activation, since the inhibition of HO-1 prevented the inhibitory effect of the NO donor (S-nitroso-N-acetylpenicillamine) on LPS-induced ICAM-1 expression. Taken together, these results suggest that CO inhibits ICAM-1 expression on endothelium by a mechanism dependent on sGC activation. Thus, our findings identify the HO-1/CO/guanosine 3`5`-cyclic monophosphate pathway as a potential target for the development of novel pharmacotherapy to control neutrophil migration in inflammatory diseases.