Anti-inflammatory activity of the leukotriene B4 receptor antagonist,SC-41930, in colitic cotton-top tamarins

Cotton-top tamarins (CTTs) with histologically confirmed persistent and active colitis were given the leukotriene B₄ (LTB₄) receptor antagonist, SC-41930, (10 mg/kg BW, by gavage b.i.d.) for eight weeks. Anti-inflammatory activity was evaluated by colonic biopsy, stool consistency and the level of the lipid mediators LTB₄ and prostaglandin E₂ (PGE₂) in rectal dialysates. Stool consistency did not improve with treatment but did not worsen. Blood chemistry (ALT, AST, LDH) and hematological parameters neither showed any untoward effects of SC-41930 treatment nor was there any effect on body weight. In rectal dialysate LTB₄ levels were significantly reduced from pretreatment level of 4.87±1.46 ng/ml to 1.07±0.67 and 2.45±0.13 ng/ml at 4 and 8 weeks, respectively, and higher prostaglandin E₂ (PGE₂) over time. Histologically, 5/7 improved, 1/7 remained the same and 1/7 worsened.

Oral SC-41930 treatment was safe and associated with an anti-colitic effect. The reduced LTB₄ levels (affecting granulocyte degranulation and recruitment into tissues) and increased PGE₂ (perhaps exerting a mucosal protective effect) may, in part explain the observed efficacy of this compound in active tamarin colitis. Use of the CTT model could provide insight into the inflammatory mediator contribution to idiopathic colitis and serve as a useful bridge between preclinical pharmacology and the assessment of these compounds in the medical management of human inflammatory bowel disease.

     

Effect of the leukotriene B4 receptor antagonist,SC-41930, on experimental allergic encephalomyelitis (EAE) in the guinea pig

The accepted model for the human demyelinating disease, multiple sclerosis (MS), is experimental allergic encephalomyelitis (EAE). We assessed the ability of SC-41930(7-[3(4-acetyl-3-methoxy-2-propylphenoxy)-propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxyl acid), to modulate the symptoms of acute EAE generated in guinea pigs. Animals were pretreated with SC-41930 (20 mg/kg, i.p.) for two days followed by thrice-weekly maintenance. At day 52, a significant number of the SC-41930-treated animals were alive as compared to EAE alone. Control animals had an increase in body weight while EAE animals lost over 20% (p<0.5) of their body weight by day 18. SC-41930-treatment significantly reduced, but did not completely inhibit the cachectic response. The results indirectly implicate LTB₄ in the pathogenesis of EAE. Agents that modify this model be useful in the treatment of human MS.     

The design and synthesis of second generation leukotriene B4 (LTB4) receptor antagonists related to SC-41930

SC-41930, 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid, is a selective, orally active, LTB₄ receptor antagonist currently in clinical trials for psoriasis and ulcerative colitis. Exhaustive SAR studies found a potential backup compound, SC-50605, which was 7–16 times more potent than SC-41930 in LTB₄ receptor binding, chemotaxis and degranulation assays. SC-50605 also inhibited LTB₄-induced intradermal chemotaxis in cavine skin at an oral dose of 0.10 mg/kg and displayed good activity in animal models of colitis and epidermal inflammation both orally and topically.     

The pharmacokinetics and metabolism of SC-53228, a specific leukotriene B4 receptor antagonist

Inflammation Research -     

SC-41930, a leukotriene B4 receptor antagonist,inhibits 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) binding to epidermal cells

SC-41930, 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxyl]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid, a potent leukotriene-B₄ (LTB₄) receptor antagonist, inhibitsin vivo 12-hydroxyei-cosatetraenoic acid (12-HETE)-induced neutrophil infiltration, suggesting a potential 12-HETE receptor antagonist effect, as well. Since 12-HETE is assumed to have a pathophysiological role in inflammatory skin diseases, and epidermal cells possess high affinity binding sites for 12(S)-HETE, we studied the effect of SC-41930 on 12(S)-HETE binding to the human epidermal cell line, SCL-II. SC-41930 antagonized the 12(S)-HETE binding to SCL-II cells with a Ki of 480 nM. This Ki value is similar to that obtained for the inhibition of LTB₄ binding to human neutrophils. Our results show that SC-41930, in addition to its LTB₄ receptor antagonist effect, exhibits 12-HETE receptor antagonist effect as well, and therefore may be of benefit in skin diseases with elevated 12-HETE levels.Dr. Kemény is on leave from the Department of Dermatology, Albert Szent-Györgyi Medical University, Szeged, Hungary, as a recipient of the Humboldt Fellowship, and his work was supported by the Alexander von Humboldt Foundation.     

Dermal inflammation in primates,mice, and guinea pigs: Attenuation by second-generation leukotriene B4 receptor antagonist,SC-53228

Granulocyte infiltration is a prominent feature of human psoriasis. Psoriatic lesional skin contains abnormally high amounts of immunoreactive leukotriene B₄ (LTB₄), a potent granulocyte chemotaxin in vivo and in vitro. SC-53228 [(+)-(S)-7-(3-{2-(cyclopropylmethyl)-3-methoxy-4-[(methylamino)carbonyl]phenoxy}propoxy)-3, 4-dihydro-8-propyl-2H-1-benzopyran-2-propanoic acid], a second-generation LTB₄ receptor antagonist, was tested topically and orally in phorbol ester-induced dermal inflammation in three species. Skin inflammation was induced by topical application of phorbol-12-myristate-13-acetate-(PMA/TPA) and assessed by ear thickness, levels of the neutrophil marker enzyme myeloperoxidase (MPO) and histological examination. In mice, SC-53228 inhibited inflammation with a topical ED₅₀ value of 200 ± 18 g. When applied to guinea pigs, SC-53228 (100 g) inhibited the MPO increase by 86%, while 1000 g abrogated inflammation in rhesus macaques with no plasma accumulation of the drug. A 1 % gel formulation was also efficacious in guinea pig PMA-induced epidermal inflammation. Furthermore, single oral dose administration to mice was efficacious (ED₅₀ < 2.5 mg/kg) as was multidose administration to rhesus macaques. PMA-induced skin inflammation possesses some of the attributes of human psoriasis and an agent such as SC-53228 may have utility in the medical management of this condition.     

Evaluation of an interleukin-1 receptor antagonist in the rat acetic acid-induced colitis model

The anti-inflammatory activity of the IL-1 receptor antagonist, IL-1ra, was evaluated in the acetic acid (HOAc)-induced model of colitis in rats. Animals treated with 10 mg/kg IL-1ra or vehicle were evaluated for general health, acute phase response, and colonic in flammation 24 hours after the initiation of inflammation. A significant decrease in the accumulation of neutrophils in the colonic mucosa as measured by myeloperoxidase activity was seen in animals with HOAc induced colitis that were treated intraperitoneally with IL-1ra when compared to animals with colitis that had been treated with vehicle. IL-1ra also reduced colonic necrosis measured grossly, although there was no effect on the histology IL-1ra had a modest effect on the HOAc-induced acute phase response, as indicated by changes in the serum iron, albumin and transferrin, but the results were not statistically significant. The number of circulating erythrocytes and neutrophils was significantly increased in animals with HOAc-induced colitis and treated with IL-1ra, suggesting that IL-1ra under these experimental conditions inhibited the migration of neutrophils to the injured colon and also the overall intestinal necrosis in the colon as assessed by gross pathology. IL-1ra may be useful as an intestinal anti-inflammatory agent.     

Pharmacological activity of the second generation leukotriene B4 receptor antagonist,SC-53228:

Inflammatory bowel disease is a chronic inflammatory disorder of the gastrointestinal tract that includes ulcerative colitis and Crohn's disease. Leukotriene B₄ is thought to be a prominent proinflammatory mediator in these diseases, in that leukotriene B₄ levels are increased in the colonic mucosa of inflammatory bowel disease patients and there is increased polymorphonuclear leukocyte infiltration of these tissues. SC-53228(+)-(S)-7-[3-[2(-cyclopropylmethyl)-3-methoxy-4-[(methylamino)carbonyl]phenoxy]propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-propanoic acid, a second generation LTB₄ receptor antagonist, was evaluated for therapeutic efficacy in a rodent model of acute colonic inflammation induced by short chain organic acids, as well as for effects on rodent liver. When given intracolonically to mice, SC-53228 inhibited neutrophil infiltration, assessed by myeloperoxidase (MPO) levels, with an ED₅₀ value of 9±1.2 mg/kg. When given by gavage, SC-53228 inhibited neutrophil influx in colitic mice with an ED₅₀ value of 30 mg/kg. These results were also confirmed histologically. Furthermore, high dose oral SC-53228 treatment had no effect on liver cytochrome P-450 content, fatty acyl CoA oxidase or liver weight in rats and mice. Together, these data suggest that SC-53228 may be efficacious orally and locally, as well as safe for use in trials for the medical management of IBD.     

Effects of SC-41930 on leukocyte adherence and emigration in rat mesenteric venules

This study demonstrates that SC-41930, 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid, an orally active LTB₄ receptor antagonist, reduces LTB₄-induced leukocyte adhesion and emigration in rat mesenteric venules. The mesentery of Sprague-Dawley rats was prepared for intravital microscopic examination and venules of 25–35 m were chosen for evaluation. In control animals, LTB₄ (20nM) was superfused over the mesentery for 30 min. In the treatment group SC-41930 (5 M) was superfused for 30 min, followed by a 30 min superfusion with SC-41930 and LTB₄. The LTB₄-induced increase in leukocyte adherence and emigration in postcapillary venules was significantly attenuated by pretreatment with SC-41930. Other experiments demonstrated that platelet-activating-factor-induced leukocyte adherence was not affected by SC-41930. These results indicate that SC-41930 is a potent inhibitor of LTB₄-induced leukocyte-endothelial cell adhesive interactions in postcapillary venules.     

Protective effect of gastrin-releasing peptide receptor antagonist in carrageenan-induced pleural inflammation in rats

Objective  

We report the effects of the gastrin-releasing peptide (GRP) receptor antagonist RC-3095 in an acute inflammation model induced by carrageenan.     

The Toll-interleukin-1 receptor member SIGIRR regulates colonic epithelial homeostasis, inflammation, and tumorigenesis

Despite constant contact with the large population of commensal bacteria, the colonic mucosa is normally hyporesponsive to these potentially proinflammatory signals. Here we report that the single immunoglobulin IL-1 receptor-related molecule (SIGIRR), a negative regulator for Toll-IL-1R signaling, plays a critical role in gut homeostasis, intestinal inflammation, and colitis-associated tumorigenesis by maintaining the microbial tolerance of the colonic epithelium. SIGIRR-deficient (Sigirr(-/-)) colonic epithelial cells displayed commensal bacteria-dependent homeostatic defects, as shown by constitutive upregulation of inflammatory genes, increased inflammatory responses to dextran sulfate sodium (DSS) challenge, and increased Azoxymethane (AOM)+DSS-induced colitis-associated tumorigenesis. Gut epithelium-specific expression of the SIGIRR transgene in the SIGIRR-deficient background reduced the cell survival of the SIGIRR-deficient colon epithelium, abrogated the hypersensitivity of the Sigirr(-/-) mice to DSS-induced colitis, and reduced AOM+DSS-induced tumorigenesis. Taken together, our results indicate that epithelium-derived SIGIRR is critical in controlling the homeostasis and innate immune responses of the colon to enteric microflora.     

The healing effect of licorice extract in acetic acid-induced ulcerative colitis in rat model

Several studies have shown the antioxidant and anti-inflammatory effects of licorice extract. This study aims to evaluate the anti-inflammatory and healing effects of licorice extract in acetic acid-induced ulcerative colitis (UC) in rat as an animal model. In summer 2008, forty-eight male Wistar rats were divided into six equal groups. Group I as normal control group received 0.5?ml/kg normal saline; group II, 0.5?ml/kg saline after induction of UC with 3% acetic acid; group III, 50?mg/kg licorice extract orally; group IV, 100?mg/kg licorice extract orally; group V, 150?mg/kg licorice extract orally; and group VI, 150?mg/kg licorice extract intracolonic. In all animals, the distal 10-cm portion of the colon was removed after 7?days for macroscopic and histological investigation. Inflammation following acetic acid administration was characterized by edema, diffuse inflammatory cell infiltration, and necrosis. Administration of oral 100 and 150?mg/kg and intracolonic 150?mg/kg of licorice extract significantly reduced the colonic inflammatory response and edema. Intracolonic administration of licorice extract showed more anti-inflammatory and healing effects in comparison to other groups. Therefore, licorice extract can be suggested as a therapeutic of choice in UC.     

Influence of the H3/H4 receptor antagonist,thioperamide on regional haemodynamics in rats with trinitrobenzene sulfonic acid-induced colitis

Inflammation Research -     

Antiinflammatory effects of second-generation leukotriene B4 receptor antagonist,SC-53228: Impact upon Leukotriene B4- and 12(R)-HETE- mediated events

Leukotriene B₄ (LTB₄) and 12(R)-hydroxyeicosatetraenoic acid [12(R)-HETE] are proinflammatory products of arachidonic acid metabolism that have been implicated as mediators in a number of inflammatory diseases. When injected intradermally into the guinea pig, LTB₄ and 12(R)-HETE elicit a dose-dependent migration (chemotaxis) of neutrophils (PMNs) into the injection sites as assessed by the presence of a neutrophil marker enzyme myeloperoxidase. SC-41930 {7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxyl]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid}, a first-generation LTB₄ receptor antagonist, inhibited the chemotactic actions of LTB₄ when given orally with an ED₅₀ value of 1.7 mg/kg. The second-generation LTB₄ receptor antagonist, SC-53228 [(+)-(S)-7-(3-{2-(cyclopropylmethyl)-3-methoxy-4-[(methylamino)carbonyl]phenoxy} propoxy)-3,4-dihydro-8-propyl-2H-1-benzopyran-2-propanoic acid], inhibited LTB₄-induced chemotaxis when given intragastrically with an ED₅₀ value of 0.07 mg/kg. Furthermore, SC-53228 inhibited 12(R)-HETE-induced granulocyte chemotaxis with an oral ED₅₀ value of 5.8 mg/kg. When dosed orally over a range of 0.03–100 mg/kg, SC-53228 gaveC _max plasma concentrations of 0.015–41.1g/ml. SC-53228 inhibited LTB₄-primed membrane depolarization of human neutrophils with an IC₅₀ value of 34 nM. As a potent LTB₄ receptor antagonist, SC-53228 may well have application in the medical management of disease states such as asthma, rheumatoid arthritis, inflammatory bowel disease, contact dermatitis, and psoriasis, in which LTB₄ and/or 12(R)-HETE are implicated as inflammatory mediators.     

Effect of a very late antigen-4 receptor antagonist on allergen-induced airway responses and inflammation in asthma

BACKGROUND: Very late antigen-4 (VLA(4)) plays a key role in the recruitment of eosinophils in allergic responses in animal studies. OBJECTIVE: We investigated whether pretreatment with multiple doses of a VLA(4) receptor antagonist, HMR 1031, protects against allergen-induced airway responses and airway inflammation in humans. METHODS: Fourteen asthmatics (7F/7M), 18-49 years, PC(20) forced expiratory volume in 1 s (FEV(1)) methacholine (M) (<8 mg/mL; FEV(1) 82.3-116.1% predicted) with dual responses to inhaled allergen participated in a double-blind, placebo-controlled, cross-over study. Each treatment period consisted of 9 days, separated by >or=2 weeks. Exhaled nitric oxide (eNO), PC(20)FEV(1)(M) and hypertonic saline-induced sputum was obtained on Days 1, 7 and 9. Subjects inhaled HMR 1031 (20 mg b.i.d.) or placebo (P) on Days 1--8. On Day 8, an allergen bronchoprovocation test was performed, the airway response was measured by FEV(1), and expressed as %fall from baseline. Data from 12 evaluable subjects are presented here. RESULTS: Both treatments were well tolerated. There was no significant difference between HMR 1031 and P in the early asthamatic response: mean AUC (0-3 h)+/-SEM (%fall h): 26.01+/-4.26 and 17.41+/-4.26, respectively (P=0.18), nor in the late response: mean AUC (3-9 h)+/-SEM (%fall h): 97.09+/-8.63 and 97.61+/-8.63, respectively, P=0.97. This corresponded to the absence of significant allergen-induced changes in PC(20)FEV(1)(M), eNO, sputum eosinophils and soluble inflammation markers between both treatment periods. CONCLUSIONS: Treatment with multiple inhaled doses of the VLA(4) antagonist, HMR 1031, did not result in detectable protection against allergen-induced airway responses or airway inflammation in asthma.     

Modulation of the chemotactic properties of complement fragments C5a and C3 by the anti-inflammatory agent,SC-41930

Cleavage of the fifth component of complement yields C5a, a potent neutrophil (PMN) and eosinophil chemoattractant, and modulator of microvascular permeability. Similarly, but to a lesser degree, C3 increases vascular permeability and histamine release. SC-41930 (7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid), an orally-active antiinflammatory agent was tested in anin vivo model of dermal PMN chemotaxis induced by r-hu-C5a and hu-C3. Intradermal injection of C5a in the guinea pig resulted in a significant dose-dependent influx of PMNs at 4 hours as assessed by the dermal levels of myeloperoxidase (MPO). SC-41930 (20 mg/kg) given orally to guinea pigs with intradermal injections of 1 μg C5a significantly (p<0.001) reduced dermal MPO content. SC-41930 was less potent against C3, requiring 40 mg/kg to significantly reduce dermal MPO levels. Agents such as SC-41930, which nullify complement's proinflammatory properties, may well have therapeutic potential.     

NPS 2143, a selective calcium-sensing receptor antagonist inhibits lipopolysaccharide-induced pulmonary inflammation

NPS 2143, a novel and selective antagonist of calcium-sensing receptor (CaSR) has been reported to possess anti-inflammatory activity. In the present study, we examined the protective effect of NPS 2143 on lipopolysaccharide (LPS)-induced acute lung injury (ALI). NPS 2143 pretreatment significantly inhibited the influx of inflammatory cells and the expression of monocyte chemoattractant protein-1 (MCP-1) in the lung of mice with LPS-induced ALI. NPS 2143 decreased the levels of neutrophil elastase (NE) and protein concentration in the bronchoalveolar lavage fluid (BALF). NPS 2143 also reduced the production of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the BALF and serum. In addition, NPS 2143 attenuated the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and increased the activation of AMP-activated protein kinase (AMPK) in the lung. NPS 2143 also downregulated the activation of nuclear factor-kappa B (NF-κB) in the lung. In LPS-stimulated H292 airway epithelial cells, NPS 2143 attenuated the releases of IL-6 and MCP-1. Furthermore, NPS 2143 upregulated the activation of AMPK and downregulated the activation of NF-κB. These results suggest that NPS 2143 could be potential agent for the treatment of inflammatory diseases including ALI.     

The effect of a selective 5-lipoxygenase inhibitor,zileuton, on tissue damage in acute colonic inflammation in rats

Though the mechanism of tissue damage induced by colonic inflammation in ulcerative colitis is unknown, it has been established that the inflammatory mediator and potent neutrophil (PMN) chemotaxin, leukotriene B4(LTB₄), is present in elevated amounts in the inflamed mucosa. The unique role of 5-lipoxygenase in the production of leukotrienes has made it a target for inhibition. This study used a rat model of acute colonic inflammation induced by a single IP injection of Mitomycin-C to test the efficacy of a specific and potent 5-lipoxygenase inhibitor zileuton in the treatment of colonic inflammation. We hypothesized that after inducing colitis in rats with mitomycin-C, the administration of oral zileuton would inhibit leukotriene production, thus preventing PMN infiltration and subsequent tissue damage. Zileuton decreased colonic tissue damage as measured by Histological score. However, zileuton did not significantly decrease neutrophil infiltration measured by mucosal PMN or myeloperoxidase (MPO) levels. Although zileuton was successful in significantly decreasing the frequency of severe colitis in our model, the fact that the decrease in PMN count and MPO level was not statistically significant suggests that another mechanism may be involved in its anti-inflammatory effect.     

Effect of oligofucose derivatives on acetic acid-induced gastric ulcer in rats

This study attempted to enhance the anti-ulcer activity of fucoidan from Cladosiphon okamuranus TOKIDA by chemical modification with a hydrophobic group. The suitable number of fucose residues in the effective compound was also clarified to obtain a compound of constant quality. Degraded fucoidans were coupled with several hydrophobic groups via Schiff bases, and their anti-ulcer activities were determined by acetic acid-induced ulcer models in rats. Size-fractionated oligofucose was also modified and assayed for anti-ulcer activity. Among the modified oligofucoses, only the oligofucose-dodecylaniline combination (OFDA) significantly promoted ulcer healing. The effective dose was 0.2 mg/kg/d. The most suitable number of fucose residues in the compound for the anti-ulcer activity was determined to be around 12. We succeeded in enhancing the anti-ulcer activity of Cladosiphon fucoidan by modification with dodecylaniline. The activity of this compound was comparable or greater than that of typical anti-ulcer agents. By determination of the optimal OF chain length for the anti-ulcer activity of OFDA, it became possible to obtain OFDA of constant quality.     

The effect of inhalation of the leukotriene receptor antagonist, SK&F 104353, on leukotriene C4- and leukotriene E4-induced bronchoconstriction in subjects with asthma.

The effect of prior inhalation of the sulfidopeptide leukotriene receptor antagonist, SK&F 104353 (963 +/- 43.7 micrograms; mean +/- SEM), on (LTC4)- and leukotriene E4 (LTE4)-induced bronchoconstriction has been studied in six subjects with asthma (six male subjects, aged 24 to 36 years). Inhalation challenges with either synthetic LTC4 or LTE4 were performed after prior inhalation of aerosolized SK&F 104353 or placebo in a double-blind, randomized fashion. Airway responsiveness to each agonist was determined by the cumulative dose of agonist required to induce a 35% fall in specific airway conductance (PD35) as determined by linear interpolation of the log dose-response curve. There was no change in baseline specific airway conductance after inhalation of either placebo or SK&F 104353. LTC4- and LTE4-induced bronchoconstrictions were significantly inhibited by aerosolized inhalation of SK&F 104353 30 minutes before challenge. The geometric mean (GM) PD35 of LTC4 on the open-therapy and placebo-therapy days was 0.043 nmol (range, 0.01 to 0.1 nmol) and 0.036 nmol (range, 0.01 to 0.1 nmol), respectively. On the treatment day with SK&F 104353, it was not possible to obtain a GM PD35 LTC4 up to a maximum concentration of 0.52 nmol LTC4 (p less than 0.01). The GM PD35 of LTE4 on the open-therapy and placebo-therapy days was 0.30 nmol (range, 0.13 to 0.76 nmol) and 0.39 nmol (range, 0.14 to 0.9 nmol), respectively. On the treatment day with SK&F 104353, it was not possible to obtain a GM PD35 LTE4 up to a maximum concentration of 5 nmol LTE4 (p less than 0.005). Thus, LTC4- and LTE4-induced bronchoconstrictions are both inhibited by SK&F 104353.