The Alpha-Lipoic Acid Improves Survival and Prevents Irinotecan-Induced Inflammation and Intestinal Dysmotility in Mice.

Irinotecan, an anticancer drug, induces diarrhea and intestinal inflammation, resulting in an increase in the cost of care and in treatment delays. In this study, we investigated whether alpha-lipoic acid (α-LA) could improve irinotecan-mediated intestinal inflammation, diarrhea and dysmotility. Intestinal mucositis was induced by irinotecan injection (75 mg/kg, i.p., for 4 days) in Swiss mice. α-LA (50, 100 or 200 mg/kg, gavage) was administered daily 1 h before the injection of irinotecan. Duodenum tissues were obtained for inflammation and proliferation analysis. The outcomes: diarrhea, intestinal dysmotility, weight body loss and survival were evaluated. Compared with the control condition, irinotecan diminished (p < 0.05) intestinal villus height, caused a loss of crypt integrity and intense inflammatory cell infiltration, increased myeloperoxidase (MPO), IL-6 and IL-1ß levels and decreased reduced glutathione (GSH) levels in duodenum segments and increased gastric retention and decreased liquid retention in the medial intestinal segment, resulting in increased intestinal transit, severe diarrhea and reduced survival (approximately 72%). Furthermore, α-LA (200 mg/kg) pretreatment ameliorated (p < 0.05) these irinotecan-induced effects. Our findings show that α-LA reduced irinotecan-induced inflammation, intestinal dysmotility and diarrhea, resulting in improved survival. α-LA may be a useful therapeutic agent for the treatment of gut dysmotility in patients with intestinal mucositis associated with irinotecan treatment.

Carvacryl acetate, a novel semisynthetic monoterpene ester, binds to the TRPA1 receptor and is effective in attenuating irinotecan-induced intestinal mucositis in mice.

OBJECTIVES: We aimed to determine whether carvacryl acetate acts as a TRPA1 receptor agonist and its effects against irinotecan (CPT-11) induced intestinal mucositis in mice. METHODS: TRPA1 structure was obtained from a protein databank, and the 3D structure of carvacryl acetate was determined. Appropriate binding conformations were discovered via automatic docking simulations. To determine the effect of carvacryl acetate in vivo, mice were treated with either DMSO 2%, CPT-11, carvacryl acetate followed by CPT-11, or HC-030031, a TRPA1 antagonist, followed by carvacryl acetate. Jejunum samples were taken and structural, inflammatory and antioxidant parameters were studied. KEY FINDINGS: Eight amino acids residues in TRPA1 established stable interactions with carvacryl acetate, which led to pharmacological efficacy against CPT-11-induced intestinal mucositis via reduction of both neutropenia and bacteremia, increase in villi height and crypt depth, decrease in pro-inflammatory cytokines (interleukin-1ß, keratinocyte chemoattractant and tumour necrosis factor-α) and decrease in malondialdehyde and nitric oxide metabolite levels in the jejunum. CONCLUSIONS: Carvacryl acetate is a promising anti-inflammatory and antioxidant agent, a fact confirmed through observations of its interactions with TRPA1 in CPT-11-induced intestinal mucositis in mice.

Carvacrol reduces irinotecan-induced intestinal mucositis through inhibition of inflammation and oxidative damage via TRPA1 receptor activation.

Intestinal mucositis is an inflammatory process occurring in the intestinal mucosa and is a common side effect of irinotecan hydrochloride (CPT-11) based anticancer regimens. The transient receptor potential cation channel, subfamily A, member 1 (TRPA1) receptor is highly expressed in the intestinal mucosa and has the ability to identify cell damage signaling indicates its possible association with intestinal mucositis. Carvacrol is an agonist of the TRPA1 receptor and has anti-inflammatory properties. Thus, the aim of the present study was to verify the supposed anti-inflammatory and protective action of carvacrol via TRPA1 activation against intestinal mucositis induced by CPT-11 in mice. Briefly, mice were treated with either DMSO 2% or CPT-11 (75 mg/kg, per 4 days, i.p.) or the carvacrol (25, 75 or 150 mg/kg, per 8 days, i.p.) before CPT-11. In other group, the animals were pretreated with HC-030031, a TRPA1 antagonist, 30 min before treatment with carvacrol. On day 7, animal survival and bacteremia were assessed, and following euthanasia, samples of the jejunum were obtained for morphometric analysis and measurement of antioxidant and pro-inflammatory markers. Carvacrol was found to exert an anti-inflammatory action against CPT-11-induced intestinal mucositis through strong interactions with TRPA1 receptors; reduction in the production or release or both of pro-inflammatory cytokines (TNF-α, IL-1ß, and KC); and decrease in other indicators of inflammation (MPO, NF-κB, COX-2) and oxidative stress (GSH, MDA, and NOx levels). It also contributed to the restoration of the tissue architecture of the villi and crypts in the small intestine, and improved clinical parameters such as survival, body mass variation, leukogram, and blood bacterial count. Thus, TRPA1 could be a target for future therapeutic approaches in the treatment of intestinal mucositis.

Regulatory role of Lactobacillus acidophilus on inflammation and gastric dysmotility in intestinal mucositis induced by 5-fluorouracil in mice.

PURPOSE: Lactobacillus acidophilus is widely used for gastrointestinal disorders, but its role in inflammatory conditions like in chemotherapy-induced mucositis is unclear. Here, we report the effect of L. acidophilus on 5-fluorouracil-induced (5-FU) intestinal mucositis in mice. METHODS: Mice weighing 25-30 g (n = 8) were separated into three groups, saline, 5-FU, and 5-FU + L. acidophilus (5-FU-La) (16 × 10(9) CFU/kg). In the 5-FU-La group, L. acidophilus was administered concomitantly with 5-FU on the first day and alone for two additional days. Three days after the last administration of L. acidophilus, the animals were euthanized and the jejunum and ileum were removed for histopathological assessment and for evaluation of levels of myeloperoxidase activity, sulfhydryl groups, nitrite, and cytokines (TNF-α, IL-1ß, CXCL-1, and IL-10). In addition, we investigated gastric emptying using spectrophotometry after feeding a 1.5-ml test meal by gavage and euthanasia. Data were submitted to ANOVA and Bonferroni's test, with the level of significance at p < 0.05. RESULTS: Intestinal mucositis induced by 5-FU significantly (p < 0.05) reduced the villus height-crypt depth ratio and GSH concentration and increased myeloperoxidase activity and the nitrite concentrations compared with the control group. Furthermore, 5-FU significantly (p < 0.05) increased cytokine (TNF-α, IL-1ß, and CXCL-1) concentrations and decreased IL-10 concentrations compared with the control group. 5-FU also significantly (p < 0.05) delayed gastric emptying and gastrointestinal transit compared with the control group. All of these changes were significantly (p < 0.05) reversed by treatment with L. acidophilus. CONCLUSIONS: Lactobacillus acidophilus improves the inflammatory and functional aspects of intestinal mucositis induced by 5-FU.

Anti-inflammatory potential of zootherapeutics derived from animals used in Brazilian traditional medicine.

CONTEXT: Animals are used for the treatment of diseases caused by inflammatory processes, although few studies evaluate their potential for these purposes. OBJECTIVES: To evaluate the anti-inflammatory potential of zootherapeutic products derived from vertebrates used in Brazilian traditional medicine. MATERIAL AND METHODS: The species analyzed were Tupinambis merianae, Iguana iguana, Crotalus durissus, Boa constrictor, and Euphractus sexcinctus. The methods used in anti-inflammatory assays were ear edema (topical) and paw (systemic). RESULTS: With regard to topical anti-inflammatory activity, the fat from T. merianae, C. durissus, I. iguana, B. constrictor, and E. sexcinctus reduced inflammation, while for systemic anti-inflammatory activity, only the fat and the skin of C. durissus, the skin of I. iguana and the fat from B. constrictor reduced inflammation. CONCLUSIONS: Studies should be conducted to evaluate the mechanisms of action for each product that demonstrated anti-inflammatory activity as well as against other inflammatory processes.

Inflammatory intestinal damage induced by 5-fluorouracil requires IL-4.

BACKGROUND: 5-Fluorouracil (5-FU) induces intestinal mucositis, which is characterized by epithelial ulcerations in the mucosa and clinical manifestations, such as pain and dyspeptic symptoms. Cytokines participate in the inflammatory and functional events of intestinal mucositis. IL-4 is an important mediator of intestinal inflammation, with either anti-inflammatory or pro-inflammatory functions, depending on the model of intestinal inflammation. This study aimed to evaluate the role of IL-4 in 5-FU-induced intestinal mucositis. METHODS: IL-4+/+ or IL-4-/- mice (25-30 g) were intraperitoneally injected with 5-FU (450 mg/Kg) or saline (C). After 3 days, the mice were sacrificed and the duodenum was evaluated for epithelial damage, MPO activity and cytokine concentration. RESULTS: 5-FU induced significant damage in the intestinal epithelium of IL-4+/+ mice (reduction in the villus/crypt ratio: control=3.31±0.21 µm, 5-FU=0.99±0.10 µm). However, the same treatment did not induce significant damage in IL-4-/- mice (5-FU=2.87±0.19 µm) compared to wild-type mice. 5-FU-induced epithelial damage increased the MPO activity (neutrophil number) and the level of pro-inflammatory cytokines (IL-4, TNF-α, IL-1ß and CXCL-8) in the duodenum. These results were not observed in IL-4-/- mice treated with 5-FU. CONCLUSION: Our data suggest that IL-4 participates as a pro-inflammatory cytokine in a 5-FU-induced intestinal damage model and suggests that IL-4 antagonists may be novel therapeutics for this condition.

The role of endothelium in the vasorelaxant effects of the essential oil of Ocimum gratissimum in aorta and mesenteric vascular bed of rats.

This study investigated the endothelium-dependent vasorelaxant effects of the essential oil of Ocimum gratissimum (EOOG) in aortas and mesenteric vascular beds isolated from rats. EOOG (3-300 µg/mL) relaxed the tonic contractions induced by phenylephrine (0.1 µmol/L) in isolated aortas in a concentration-dependent manner in both endothelium-containing and endothelium-denuded preparations. This effect was partially reversed by L-NAME (100 µmol/L) but not by indomethacin (10 µmol/L) or TEA (5 mmol/L). In mesenteric vascular beds, bolus injections of EOOG (30, 50, 100, and 300 ng) decreased the perfusion pressure induced by noradrenaline (6 µmol/L) in endothelium-intact preparations but not in those treated with deoxycholate. L-NAME (300 µmol/L) but not TEA (1 mmol/L) or indomethacin (3 µmol/L) significantly reduced the vasodilatory response to EOOG at all of the doses tested. Our data showed that EOOG exerts a dose-dependent vasodilatory response in the resistance blood vessels of rat mesenteric vascular beds and in the capacitance blood vessel, the rat aorta. This action is completely dependent on endothelial nitric oxide (NO) release in the mesenteric vascular beds but only partially dependent on NO in the aorta. These novel effects of EOOG highlight interesting differences between resistance and capacitance blood vessels.

Purification, characterization, and preliminary X-ray diffraction analysis of a lactose-specific lectin from Cymbosema roseum seeds.

The unique carbohydrate-binding property of lectins makes them invaluable tools in biomedical research. Here, we report the purification, partial primary structure, carbohydrate affinity characterization, crystallization, and preliminary X-ray diffraction analysis of a lactose-specific lectin from Cymbosema roseum seeds (CRLII). Isolation and purification of CRLII was performed by a single step using a Sepharose-4B-lactose affinity chromatography column. The carbohydrate affinity characterization was carried using assays for hemagglutination activity and inhibition. CRLII showed hemagglutinating activity toward rabbit erythrocytes. O-glycoproteins from mucine mucopolysaccharides showed the most potent inhibition capacity at a minimum concentration of 1.2 microg mL(-1). Protein sequencing by mass spectrometry was obtained by the digestion of CRLII with trypsin, Glu-C, and AspN. CRLII partial protein sequence exhibits 46% similarity with the ConA-like alpha chain precursor. Suitable protein crystals were obtained with the hanging-drop vapor-diffusion method with 8% ethylene glycol, 0.1 M Tris-HCl pH 8.5, and 11% PEG 8,000. The monoclinic crystals belong to space group P2(1) with unit cell parameters a = 49.4, b = 89.6, and c = 100.8 A.

Effects of anethole and structural analogues on the contractility of rat isolated aorta: Involvement of voltage-dependent Ca2+-channels.

Anethole is a naturally occurring aromatic oxidant, present in a variety of medicinal plant extracts, which is commonly used by the food and beverage industry. Despite its widespread occurrence and commercial use, there is currently little information regarding effects of this compound on the vasculature. Therefore the actions of anethole on the contractility of rat isolated aorta were compared with those of eugenol, and their respective isomeric forms, estragole and isoeugenol. In aortic rings precontracted with phenylephrine (PE; 1 microM), anethole (10(-6) M-10(-4) M) induced contraction in preparations possessing an intact endothelium, but not in endothelium-denuded tissues. At higher concentrations (10(-3) M-10(-2) M), anethole-induced concentration-dependent and complete relaxation of all precontracted preparations, irrespective of whether the endothelium was intact or not, an action shared by eugenol, estragole and isoeugenol. The contractile and relaxant effects of anethole in PE-precontracted preparations were not altered by L-NAME (10 microM) or indomethacin (10 microM), indicating that neither nitric oxide nor prostaglandins were involved in these actions. The mixed profile of effects was not confined to PE-mediated contraction, since similar responses were obtained to anethole when tissues were precontracted with 25 mM KCl. Anethole and estragole (10(-6)-10(-4) M), but not eugenol or isoeugenol, increased the basal tonus of endothelium-denuded aortic rings, an action that was abolished by VDCC blockers nifedipine (1 microM) and diltiazem (1 microM), or by withdrawal of extracellular Ca(2+). Our data suggest complex effects of anethole on isolated blood vessels, inducing contraction at lower doses, mediated via opening of voltage-dependent Ca(2+)-channels, and relaxant effects at higher concentrations that are shared by structural analogues.

Structure of a lectin from Canavalia gladiata seeds: new structural insights for old molecules.

BACKGROUND: Lectins are mainly described as simple carbohydrate-binding proteins. Previous studies have tried to identify other binding sites, which possible recognize plant hormones, secondary metabolites, and isolated amino acid residues. We report the crystal structure of a lectin isolated from Canavalia gladiata seeds (CGL), describing a new binding pocket, which may be related to pathogen resistance activity in ConA-like lectins; a site where a non-protein amino-acid, alpha-aminobutyric acid (Abu), is bound. RESULTS: The overall structure of native CGL and complexed with alpha-methyl-mannoside and Abu have been refined at 2.3 A and 2.31 A resolution, respectively. Analysis of the electron density maps of the CGL structure shows clearly the presence of Abu, which was confirmed by mass spectrometry. CONCLUSION: The presence of Abu in a plant lectin structure strongly indicates the ability of lectins on carrying secondary metabolites. Comparison of the amino acids composing the site with other legume lectins revealed that this site is conserved, providing an evidence of the biological relevance of this site. This new action of lectins strengthens their role in defense mechanisms in plants.

cDNA cloning and 1.75 A crystal structure determination of PPL2, an endochitinase and N-acetylglucosamine-binding hemagglutinin from Parkia platycephala seeds.

Parkia platycephala lectin 2 was purified from Parkia platycephala (Leguminosae, Mimosoideae) seeds by affinity chromatography and RP-HPLC. Equilibrium sedimentation and MS showed that Parkia platycephala lectin 2 is a nonglycosylated monomeric protein of molecular mass 29 407+/-15 Da, which contains six cysteine residues engaged in the formation of three intramolecular disulfide bonds. Parkia platycephala lectin 2 agglutinated rabbit erythrocytes, and this activity was specifically inhibited by N-acetylglucosamine. In addition, Parkia platycephala lectin 2 hydrolyzed beta(1-4) glycosidic bonds linking 2-acetoamido-2-deoxy-beta-D-glucopyranose units in chitin. The full-length amino acid sequence of Parkia platycephala lectin 2, determined by N-terminal sequencing and cDNA cloning, and its three-dimensional structure, established by X-ray crystallography at 1.75 A resolution, showed that Parkia platycephala lectin 2 is homologous to endochitinases of the glycosyl hydrolase family 18, which share the (betaalpha)8 barrel topology harboring the catalytic residues Asp125, Glu127, and Tyr182.

Crystal structure of a lectin from Canavalia maritima (ConM) in complex with trehalose and maltose reveals relevant mutation in ConA-like lectins.

The crystal structure of Canavalia maritima lectin (ConM) complexed with trehalose and maltose revealed relevant point mutations in ConA-like lectins. ConM with the disaccharides and other ConA-like lectins complexed with carbohydrates demonstrated significant differences in the position of H-bonds. The main difference in the ConM structure is the replacement of Pro202 by Ser202, a residue that promotes the approximation of Tyr12 to the carbohydrate-binding site. The O-6' of the second glucose ring in maltose interacts with Tyr12, while in trehalose the interaction is established by the O-2' and Tyr12, explaining the higher affinity of ConM for disaccharides compared to monosaccharides.

Purification, partial characterization and preliminary X-ray diffraction analysis of a mannose-specific lectin from Cymbosema roseum seeds.

A lectin from Cymbosema roseum seeds (CRL) was purified, characterized and crystallized. The best crystals grew in a month and were obtained by the vapour-diffusion method using a precipitant solution consisting of 0.1 M Tris-HCl pH 7.8, 8%(w/v) PEG 3350 and 0.2 M proline at a constant temperature of 293 K. A data set was collected to 1.77 A resolution at a synchrotron-radiation source. CRL crystals are orthorhombic, belonging to space group P2(1)2(1)2(1). Crystallographic refinement and full amino-acid sequence determination are in progress.

Helianthus tuberosus agglutinin directly induces neutrophil migration, which can be modulated/inhibited by resident mast cells.

We investigated the effect of Helianthus tuberosus agglutinin (HTA) on neutrophil migration in vivo and in vitro. The role of resident cells in this effect was analyzed. Peritonitis was induced by injecting stimuli into rat (150-200 g) peritoneal cavities, and in vitro neutrophil chemotaxis was performed using a Boyden microchamber. HTA (80, 200, or 500 microg/mL per cavity) induced significant in vivo neutrophil migration (p < 0.05); in vitro assays showed that this lectin also induced neutrophil chemotaxis, an effect inhibited by the incubation of lectin associated with alpha-D(+)-mannose, its specific binding sugar. Depletion of the resident-cell population by peritoneal lavage did not alter HTA-induced neutrophil migration (200 microg/mL per cavity). The opposite strategy, increasing peritoneal macrophages by intraperitoneally injecting rats with thioglycollate, did not enhance the neutrophil migration produced by HTA (200 microg/mL per cavity). In addition, injection of supernatant from HTA-stimulated macrophage culture (300 microg/mL) into rat peritoneal cavities did not induce neutrophil migration. However, reduction of the peritoneal mast-cell population potentiated the neutrophil migration (p < 0.05) induced by HTA (200 microg/mL per cavity). Lectin from H. tuberosus has a direct neutrophil chemotatic effect that is modulated by mast cells.

Red marine alga Bryothamnion triquetrum lectin induces endothelium-dependent relaxation of the rat aorta via release of nitric oxide.

We have investigated the vascular relaxant effects of the lectin from a red marine alga Bryothamnion triquetrum (BTL), in particular, the endothelial-dependency and the participation of a specific glycoprotein-binding site. BTL (1-100 microg mL(-1)) was applied to rat isolated aortic rings, with or without endothelium, tonically precontracted with phenylephrine (0.1 microM). Endothelium-dependent relaxation was assessed in the presence of indometacin (10 microM), L-nitro arginine methyl ester (L-NAME, 100 microM) and tetraethylammonium (TEA, 500 microM). For the involvement of the glycoprotein-binding site, BTL was assayed in presence of mucin (300 microg mL(-1)) or N-acetyl D-glucosamine (GlcNAc; 300 microg mL(-1)), a specific and non-specific lectin-binding sugar, respectively. BTL fully and concentration dependently relaxed preparations that possessed an intact endothelium (IC50 (concn producing 50% contraction) = 12.1 +/- 1.6 microg mL(-1)), whereas no significant relaxation was observed in endothelial-denuded tissue. L-NAME, but not indometacin or TEA, completely inhibited the lectin relaxation, suggesting the involvement of nitric oxide (NO). The lectin in association with mucin, but not with GlcNAc, inhibited BTL-induced relaxation, implicating the involvement of the lectin binding site. Our data suggest that the relaxant effect of the red marine alga Bryothamnion triquetrumlectin on isolated aorta occurs via interaction with a specific lectin-binding site on the endothelium, resulting in a release of NO.

Crystallization and preliminary X-ray diffraction analysis of the lectin from Canavalia gladiata seeds.

The seed lectin from Canavalia gladiata was purified and crystallized. Orthorhombic crystals belonging to space group C222(1) grew within three weeks at 293 K using the hanging-drop vapour-diffusion method. Using synchrotron X-ray radiation, a complete structural data set was collected at 2.3 A resolution. The preliminary crystal structure of the lectin, determined by molecular replacement, had a correlation coefficient of 0.569 and an R factor of 0.412.

Effects of chloride channel blockers on hypotonicity-induced contractions of the rat trachea.

1. We have investigated the inhibitory effects of blockers of volume-activated (Cl(vol)) and calcium-activated (Cl(Ca)) chloride channels on hypotonic solution (HS)-induced contractions of rat trachea, comparing their effects with those of the voltage-dependent calcium channel (VDCC) blocker nifedpine. 2. HS elicited large, stable contractions that were partially dependent on the cellular chloride gradient; a reduction to 41.45+/-7.71% of the control response was obtained when extracellular chloride was removed. In addition, HS-induced responses were reduced to 26.8+/-5.6% of the control by 1 microm nifedipine, and abolished under calcium-free conditions, indicating a substantial requirement for extracellular calcium entry, principally via VDCCs. 3. The established Cl(vol) blockers tamoxifen (