The Novel H4R Antagonist 1-[(5-Chloro-2,3-Dihydro-1-Benzofuran-2-Yl)Methyl]-4-Methyl-Piperazine (LINS01007) Attenuates Several Symptoms in Murine Allergic Asthma.

BACKGROUND/AIMS: Histamine is an important chemical transmitter involved in inflammatory processes, including asthma and other chronic inflammatory diseases. Its inflammatory effects involve mainly the histamine H4 receptor (H4R), whose role in several studies has already been demonstrated. Our group have explored the effects of 1-[(2,3-dihydro-1-benzofuran-2-yl)methyl]piperazines as antagonists of H4R, and herein the compounds LINS01005 and LINS01007 were studied with more details, considering the different affinity profile on H4R and the anti-inflammatory potential of both compounds. METHODS: We carried out a more focused evaluation of the modulatory effects of LINS01005 and LINS01007 in a murine asthma model. The compounds were given i.p. (1-7 mg/kg) to ovalbumin sensitized BALB/c male mice (12 weeks old) 30 min before the antigen challenging, and after 24 h the cell analysis from the bronchoalveolar lavage fluid (BALF) was performed. The lung tissue was used for evaluation by western blot (COX-2, 5-LO, NF-κB and STAT3 expressions) and histological analysis. RESULTS: Treatment with the more potent H4R antagonist LINS01007 significantly decreased the total cell count and eosinophils in BALF at lower doses when compared to LINS01005. The expression of COX-2, 5-LO, NF-κB and STAT3 in lung tissue was significantly reduced after treatment with LINS01007. Morphophysiological changes such as mucus and collagen production and airway wall thickening were significantly reduced after treatment with LINS01007. CONCLUSION: These results show important down regulatory effect of novel H4R antagonist (LINS01007) on allergic lung inflammation.

Intrauterine Malnutrition Reduced Long Leptin Receptor Isoform Expression and Proinflammatory Cytokine Production in Male Rat Pulmonary Endothelial Cells Stimulated by Lipopolysaccharide.

BACKGROUND/AIMS: We have previously shown that low birth weight (LBW) rats exposed to intrauterine malnutrition have an impaired lung inflammatory response and reduced levels of inflammatory mediators; however, circulating leptin levels were not increased. We evaluated long leptin receptor isoform (ObRb) expression in lung endothelial cells from low birth weight rats and examined its role in the production of lipid mediators and cytokines. METHODS: Lung endothelial cells were obtained from normal birth weight (NBW) rats or LBW rats subjected to intrauterine malnutrition. These cells were stimulated with leptin (10 ng/mL), LPS (lipopolysaccharide, 1 µg/mL), or leptin plus LPS. Six hours after stimulation, the production of inflammatory mediators (PGE2, LTB4, IL-1ß, and IL-6) was evaluated using commercial ELISA kits, and Western blotting was performed to investigate p38MAPK, NF-κB, and ObRb expression. RESULTS: Leptin increased IL-1ß levels in only cells from the NBW group, whereas LPS increased PGE2 and LTB4 levels in cells from both groups; leptin addition potentiated lipid mediator production induced by LPS in the NBW group. LPS enhanced the production of IL-1ß and IL-6 in only endothelial cells from NBW rats. Leptin receptor expression was decreased (63%) in endothelial cells from LBW rats. None of the stimuli increased NF-κB or p38 signaling pathway expression in cells from LBW rats. CONCLUSION: These results suggest that intrauterine malnutrition compromises leptin receptor expression and cytokine production in pulmonary endothelial cells stimulated by LPS; these effects seem to involve the NF-κB and p38MAPK signaling pathways.

Walker 256 Tumor Growth Suppression by Crotoxin Involves Formyl Peptide Receptors and Lipoxin A4.

We investigated the effects of Crotoxin (CTX), the main toxin of South American rattlesnake (Crotalus durissus terrificus) venom, on Walker 256 tumor growth, the pain symptoms associated (hyperalgesia and allodynia), and participation of endogenous lipoxin A4. Treatment with CTX (s.c.), daily, for 5 days reduced tumor growth at the 5th day after injection of Walker 256 carcinoma cells into the plantar surface of adult rat hind paw. This observation was associated with inhibition of new blood vessel formation and decrease in blood vessel diameter. The treatment with CTX raised plasma concentrations of lipoxin A4 and its natural analogue 15-epi-LXA4, an effect mediated by formyl peptide receptors (FPRs). In fact, the treatment with Boc-2, an inhibitor of FPRs, abolished the increase in plasma levels of these mediators triggered by CTX. The blockage of these receptors also abolished the inhibitory action of CTX on tumor growth and blood vessel formation and the decrease in blood vessel diameter. Together, the results herein presented demonstrate that CTX increases plasma concentrations of lipoxin A4 and 15-epi-LXA4, which might inhibit both tumor growth and formation of new vessels via FPRs.

Leptin downregulates LPS-induced lung injury: role of corticosterone and insulin.

BACKGROUND/AIMS: We investigated the effects of leptin in the development of lipopolysaccharide (LPS)-induced acute lung inflammation (ALI) in lean mice. METHODS: Mice were administered leptin (1.0µg/g) or leptin (1.0µg/g) followed by LPS (1.5µg/g) intranasally. Additionally, some animals were given LPS (1.5µg/g) or saline intranasally alone, as a control. Tissue samples and fluids were collected six hours after instillation. RESULTS: We demonstrated that leptin alone did not induce any injury. Local LPS exposure resulted in significant acute lung inflammation, characterized by a substantial increase in total cells, mainly neutrophils, in bronchoalveolar lavages (BAL). We also observed a significant lymphocyte influx into the lungs associated with enhanced lung expression of chemokines and cytokines (KC, RANTES, TNF-α, IFN-γ, GM-CSF and VEGF). LPS-induced ALI was characterized by the enhanced expression of ICAM-1 and iNOS in the lungs. Mice that received LPS showed an increase in insulin levels. Leptin, when administered prior to LPS instillation, abolished all of these effects. LPS induced an increase in corticosterone levels, and leptin potentiated this event. CONCLUSION: These data suggest that exogenous leptin may promote protection during sepsis, and downregulation of the insulin levels and upregulation of corticosterone may be important mechanisms in the amelioration of LPS-induced ALI.

Generation and characterization of a spontaneously immortalized endothelial cell line from mice microcirculation.

Endothelial cells from microvasculature are directly involved in a large number of vascular diseases; however, culture of these cells is problematic, since most methodologies employ proteolytic enzymes or mechanical techniques, leading to cell damage and contamination of endothelial cultures with other cellular types. Besides, primary cultured cells have a short life span in vitro and undergo replicative senescence after 3-4 passages, limiting long-term studies. In the present work we report the generation of a spontaneously immortalized endothelial culture obtained from mice pulmonary capillaries. Firstly, primary (third passage) and immortalized (100th) cultures were established. Further, monoclonal populations were obtained by serial dilutions from immortalized cultures. Cells were analyzed according to: (1) morphological appearance, (2) expression of specific endothelial markers by fluorescent staining [von Willebrand Factor (vWF), endothelial nitric oxide synthase (eNOS), angiotensin converting enzyme (ACE) and Ulex europaeus (UEA-1)] and by flow cytometry (endoglin, VE-cadherin and VCAM-1), and (3) release of nitric oxide (NO), assessed by the specific fluorescent dye DAF-2 DA, and prostacyclin (PGI2), quantified by enzyme immune assay. In both cultures cells grew in monolayers and presented cobblestone appearance at confluence. Positive staining for vWF, eNOS, ACE and UEA-1 was detected in cloned as well as in early-passage cultured cells. Similarly, cultures presented equal expressions of endoglin, VE-cadherin and VCAM-1. Values of NO and PGI2 levels did not differ between cultures. From these results we confirm that the described spontaneously immortalized endothelial cell line is capable of unlimited growth and retains typical morphological and functional properties exhibited by primary cultured cells. Therefore, the endothelial cell line described in the present study can become a suitable tool in the field of endothelium research and can be useful for the investigation of production of endothelial mediators, angiogenesis and inflammation.

The histamine H4 receptor antagonist 1-[(5-chloro-2,3-dihydro-1-benzofuran-2-yl)methyl]-4-methyl-piperazine(LINS01007) prevents the development of DSS-induced colitis in mice.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with growing incidence worldwide. Our group reported the compound 5-choro-1-[(2,3-dihydro-1-benzofuran-2-yl)methyl]piperazine (LINS01007) as H4R antagonist (pKi 6.2) and therefore the effects and pharmacological efficacy on a DSS-induced mice model of UC were assessed in this work. Experimental acute colitis was induced in male BALB/c mice (n = 5-10) by administering 3 % DSS in the drinking water for six days. The test compound LINS01007 was administered daily i.p. (5 mg/kg) and compared to control group without treatment. Body weight, water and food consumption, and the presence of fecal blood were monitored during 7-day treatment period. The levels of inflammatory markers (PGE2, COX-2, IL-6, NF-κB and STAT3) were also analyzed. Animals subjected to the acute colitis protocol showed a reduction in water and food intake from the fourth day (p < 0.05) and these events were prevented by LINS01007. Histological signs of edema, hyperplasia and disorganized intestinal crypts, as well as neutrophilic infiltrations, were found in control mice while these findings were significantly reduced in animals treated with LINS01007. Significant reductions in the levels of PGE2, COX-2, IL-6, NF-κB and STAT3 were observed in the serum and tissue of treated animals. The results demonstrated the significant effects of LINS01007 against DSS-induced colitis, highlighting the potential of H4R antagonism as promising treatment for this condition.

Acute kidney injury reduces phagocytic and microbicidal capacities of alveolar macrophages.

BACKGROUND/AIMS: Renal ischaemia-reperfusion injury (IRI) is a systemic inflammatory process in which Th1 responses predominate affecting other organs including the lungs. The present study explored the phagocytic and microbicidal capacity of macrophages in rats with lung inflammation that underwent IRI. METHODS: The alveolar macrophages of rats sensitised to OVA were evaluated for phagocytosis and bacterial killing 24h after antigen challenge in animals with or without prior submission to 60 min of renal ischaemia. RESULTS: Bronchoalveolar lavage had a high level of cellular infiltrate in immunised animals (420%) compared with control animals; IRI significantly reduced this infiltration (52%). Macrophages from animals immunised and challenged with OVA presented a 10x increase in phagocytic capacity compared to the control group, whereas immunised animals subjected to IRI showed a reduction in the phagocytic index of 68%. The killing of Klebsiella pneumoniae by macrophages from immunised animals was higher (56%) compared with the control group but reduced in animals submitted to IRI (45%). Immunised and challenged group showed an increase in gene expression levels of IL-10(450%), HO-1 (259%), INF-γ (460%) and MCP-1 (370%) compared to the immunised group subjected to IRI. CONCLUSIONS: Renal ischaemia and reperfusion injury apparently alters the phagocytic and microbicidal capacity of macrophages, reducing lung inflammation to OVA.

Intrauterine undernourishment alters TH1/TH2 cytokine balance and attenuates lung allergic inflammation in wistar rats.

IL-4 produced by Th2 cells can block cytokine production by Th1 cells, and Th1 IFN-γ is known to counterregulate Th2 immune response, inhibiting allergic eosinophilia. As intrauterine undernutrition can attenuate lung inflammation, we investigated the influence of intrauterine undernourishment on the Th1/Th2 cytokine balance and allergic lung inflammation. Intrauterine undernourished offspring were obtained from dams fed 50% of the nourished diet of their counterparts and were immunized at 9 weeks of age. We evaluated the cell counts and cytokine protein expression in the bronchoalveolar lavage, mucus production and collagen deposition, and cytokine gene expression and transcription factors in lung tissue 21 days after ovalbumin immunization. Intrauterine undernourishment significantly reduced inflammatory cell airway infiltration, mucus secretion and collagen deposition, in rats immunized and challenged. Intrauterine undernourished rats also exhibited an altered cytokine expression profile, including higher TNF-α and IL-1ß expression and lower IL-6 expression than well-nourished rats following immunization and challenge. Furthermore, the intrauterine undernourished group showed reduced ratios of the IL-4/IFN-γ and the transcription factors GATA-3/T-Bet after immunization and challenge. We suggest that the attenuated allergic lung inflammation observed in intrauterine undernourished rats is related to an altered Th1/Th2 cytokine balance resulting from a reduced GATA-3/T-bet ratio.

Modulation of lung allergic response by renal ischemia and reperfusion injury.

The Th1/Th2 balance represents an important factor in the pathogenesis of renal ischemia-reperfusion injury (IRI). In addition, IRI causes a systemic inflammation that can affect other tissues, such as the lungs. To investigate the ability of renal IRI to modulate pulmonary function in a specific model of allergic inflammation, C57Bl/6 mice were immunized with ovalbumin/albumen on days 0 and 7 and challenged with an ovalbumin (OA) aerosol on days 14 and 21. After 24 h of the second antigen challenge, the animals were subjected to 45 minutes of ischemia. After 24 h of reperfusion, the bronchoalveolar lavage (BAL) fluid, blood and lung tissue were collected for analysis. Serum creatinine levels increased in both allergic and non-immunized animals subjected to IRI. However, BAL analysis showed a reduction in the total cells (46%) and neutrophils (58%) compared with control allergic animals not submitted to IRI. In addition, OA challenge induced the phosphorylation of ERK and Akt and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lung homogenates. After renal IRI, the phosphorylation of ERK and expression of COX-2 and iNOS were markedly reduced; however, there was no difference in the phosphorylation of Akt between sham and ischemic OA-challenged animals. Mucus production was also reduced in allergic mice after renal IRI. IL-4, IL-5 and IL-13 were markedly down-regulated in immunized/challenged mice subjected to IRI. These results suggest that renal IRI can modulate lung allergic inflammation, probably by altering the Th1/Th2 balance and, at least in part, by changing cellular signal transduction factors.

Intrauterine growth restriction leads to a high-corticosterone producing offspring: An implication for pulmonary infection susceptibility.

AIMS: Although intrauterine growth restriction (IUGR) impairs immune system homeostasis and lung development, its relationship with the susceptibility to pulmonary infections remains unclear. Thus, this study aimed to investigate the impact of IUGR on acute lung inflammatory response induced by bacterial stimulus. MATERIALS AND METHODS: Pregnant female Wistar rats were subjected to 50% caloric-protein food restriction during gestation. To mimic bacterial lung infection, adult male offspring (12 weeks old) were challenged with a single lipopolysaccharide (LPS) intranasal instillation, and 6 h later, we assessed the acute inflammatory response. Normal birth weight (NBW) animals represent the control group. KEY FINDINGS: LPS instillation increased the protein levels in the airways of both the NBW and low birth weight (LBW) groups, indicating vascular leakage. LBW animals exhibited a lower number of neutrophils, reduced production of interleukin-6 and macrophage-inflammatory protein-2 and decreased upregulation of intercellular adhesion molecule-1 gene expression in lung tissues. Further analysis revealed that the LBW group produced lower levels of prostaglandin-E2 and failed to secrete leukotriene-B4 upon LPS stimulation, which correlated with impaired cyclooxygenase-2 and 5-lipoxygenase expression. These results were probably associated with their inability to upregulate the expression of Toll-like receptor-4 and downstream signaling proteins, such as nuclear factor kappa-B, in the lungs. The LBW group also exhibited abnormal airway thickening and high corticosterone levels under basal conditions. SIGNIFICANCE: This study suggests that IUGR-induced foetal programming in LBW offspring threatens HPA axis physiology and corticosterone biodisponibility, and impairs the innate response to bacterial antigens, increasing future susceptibility to pulmonary infection.

Leukotrienes produced in allergic lung inflammation activate alveolar macrophages.

It has been well-documented that leukotrienes (LTs) are released in allergic lung inflammation and that they participate in the physiopathology of asthma. A role for LTs in innate immunity has recently emerged: Cys-LTs were shown to enhance FcgammaR-mediated phagocytosis by alveolar macrophages (AMs). Thus, using a rat model of asthma, we evaluated FcgammaR-mediated phagocytosis and killing of Klebsiella pneumoniae by AMs. The effect of treatment with a cys-LT antagonist (montelukast) on macrophage function was also investigated. Male Wistar rats were immunized twice with OVA/alumen intraperitoneally and challenged with OVA aerosol. After 24 h, the animals were killed, and the AMs were obtained by bronchoalveolar lavage. Macrophages were cultured with IgG-opsonized red blood cells (50:1) or IgG-opsonized K. pneumoniae (30:1), and phagocytosis or killing was evaluated. Leukotriene C(4) and nitric oxide were quantified by the EIA and Griess methods, respectively. The results showed that AMs from sensitized and challenged rats presented a markedly increased phagocytic capacity via FcgammaR (10X compared to controls) and enhanced killing of K. pneumoniae (4X higher than controls). The increased phagocytosis was inhibited 15X and killing 3X by treatment of the rats with montelukast, as compared to the non-treated group. cys-LT addition increased phagocytosis in control AMs but had no effect on macrophages from allergic lungs. Montelukast reduced nitric oxide (39%) and LTC(4) (73%). These results suggest that LTs produced during allergic lung inflammation potentiate the capacity of AMs to phagocytose and kill K. pneumonia via FcgammaR.

Emerging roles for eicosanoids in renal diseases.

PURPOSE OF REVIEW: Eicosanoids are products of arachidonic acid metabolism which have important roles in renal homeostasis and disease. In recent years the development of genetically modified animals and new drugs targeting eicosanoids producing enzymes and receptors has unveiled new roles for eicosanoids in kidney function. This review provides an overview of eicosanoid biosynthesis and receptors and discusses recent findings on their role in acute and chronic renal diseases and in renal transplantation. RECENT FINDINGS: Products of the cyclooxygenases, 5-lipoxygenase, and cytochrome P450 pathways of arachidonic acid metabolism act through distinct receptors presented at different segment of the nephron. Apart from its role in renal physiology and hemodynamic, eicosanoids actively participate in the pathogenesis of acute and chronic renal diseases and have immunoregulatory role in kidney transplantation. SUMMARY: The new discoveries on the role of eicosanoids in kidney functions and the development of drugs targeting eicosanoids synthesis or action should help to envisage novel therapeutic approaches for patients suffering from renal diseases.

Insulin inhibits LPS-induced signaling pathways in alveolar macrophages.

The systemic inflammatory response syndrome (SIRS) is triggered by lipopolysaccharide (LPS) from Gram-negative bacteria. Insulin was shown to have a protective role in SIRS related to sepsis. Lungs are particularly affected in this condition and provide a second wave of mediators/cytokines which amplifies SIRS. The aim of the present study was to investigate the effect of insulin on the signaling pathways elicited by LPS in alveolar macrophages (AMs) and its consequence in cellular response to LPS measured as production of tumor necrosis factor (TNF). To this purpose, resident AMs from male Wistar rats were obtained by lung lavage and stimulated by LPS (100 ng/mL). Insulin (1 mU/mL) was added 10 min before LPS. Activation (phosphorylation) of signaling molecules by LPS was analyzed by western blot, 30 min after LPS stimulation. TNF was measured in the AMs culture supernatants by bioassay using L-929 tumor cells. Relative to controls, LPS induced a significant increase in the activation of ERK (3.6-fold), p38 (4.4-fold), Tyr-326 Akt (4.7-fold), Ser-473 Akt (6.9-fold), PKCalpha (4.7-fold) and PKCdelta (2.3-fold). Treatment of AMs with insulin before LPS stimulation, significantly reduced the activation of ERK (54%), p38 (48%), Tyr-326 Akt (64%), Ser-473 Akt (41%), PKCalpha (62%) and PKCdelta (39%). LPS induced TNF production in AMs which was also inhibited by insulin (60%). These results show that insulin down-regulates MAPK, PI3K and PKCs and inhibits a downstream effect of LPS, TNF production, in rat AMs stimulated with LPS and suggest that the protective effect of insulin in sepsis could be through modulation of signal transduction pathways elicited by LPS in lung macrophages.

Insulin suppresses LPS-induced iNOS and COX-2 expression and NF-kappaB activation in alveolar macrophages.

The development of septic shock is a common and frequently lethal consequence of gram-negative infection. Mediators released by lung macrophages activated by bacterial products such as lipopolysaccharide (LPS) contribute to shock symptoms. We have shown that insulin down-regulates LPS-induced TNF production by alveolar macrophages (AMs). In the present study, we investigated the effect of insulin on the LPS-induced production of nitric oxide (NO) and prostaglandin (PG)-E(2), on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, and on nuclear factor kappa B (NF-kappaB) activation in AMs. Resident AMs from male Wistar rats were stimulated with LPS (100 ng/mL) for 30 minutes. Insulin (1 mU/mL) was added 10 min before LPS. Enzymes expression, NF-kappaB p65 activation and inhibitor of kappa B (I-kappaB)alpha phosphorylation were assessed by immunobloting; NO by Griess reaction and PGE(2) by enzyme immunoassay (EIA). LPS induced in AMs the expression of iNOS and COX-2 proteins and production of NO and PGE(2), and, in parallel, NF-kappaB p65 activation and cytoplasmic I-kappaBalpha phosphorylation. Administration of insulin before LPS suppressed the expression of iNOS and COX-2, of NO and PGE(2) production and Nuclear NF-kappaB p65 activation. Insulin also prevented cytoplasmic I-kappaBalpha phosphorylation. These results show that in AMs stimulated by LPS, insulin prevents nuclear translocation of NF-kappaB, possibly by blocking I-kappaBalpha degradation, and supresses the production of NO and PGE(2), two molecules that contribute to septic shock.

The role of endothelin pathway in modulation of airway reactivity to methacholine in C57Bl/6 and BALB/c mice.

Endothelin peptides have been shown to increase cholinergic neurotransmission in the airway. Genetic differences in airway responsiveness to methacholine where reported in mice. The present study compared the airway reactivity to methacholine in C57Bl/6 and BALB/c mice, the involvement of endothelin on this reactivity and endothelin levels in lung homogenates. Whole airway reactivity was analyzed by means of an isolated lung preparation where lungs were perfused through the trachea with warm gassed Krebs solution at 5 ml/min, and changes in perfusion pressure triggered by methacholine at increasing bolus doses (0.1-100 microg) were recorded. We found that the maximal airway response to methacholine was much greater in C57Bl/6 than in BALB/c (Emax 34+/-2 vs 12+/-1 cmH(2)O, respectively). Bosentan (mixed endothelin A/B receptor antagonist; 10 mg/kg, i.p., 30 min before sacrifice) reduced lung responsiveness to methacholine in C57Bl/6 (58% at EC50 level) but had no effect in BALB/c mouse strain. This effect seems to be mediated by the endothelin ET(A) receptor since it was significantly reduced by the selective endothelin ET(A) receptor antagonist, BQ 123. Immunoreactive endothelin levels were higher in C57Bl/6 than in BALB/c lungs (43+/-5 vs 19+/-5 pg/g of tissue). In conclusion, airway reactivity to methacholine and lung endothelins content varies markedly between C57Bl/6 and BALB/c strains. Endothelins upregulate lung responsiveness to methacholine only in C57Bl/6, an effect achieved through the endothelin ET(A) receptor.

Endothelin A receptor antagonist modulates lymphocyte and eosinophil infiltration, hyperreactivity and mucus in murine asthma.

Levels of endothelins are particularly high in the lung, and there is evidence that these peptides are involved in asthma. Asthma is a chronic inflammatory disease associated with lymphocyte infiltration. In the present study, we used a murine model of asthma to investigate the role of endothelins in lymphocyte and eosinophil infiltration into the airway hyperreactivity and mucus secretion. Sensitized C57Bl/6 mice were treated with endothelin ETA receptor antagonist (BQ123) or endothelin ETB receptor antagonist (BQ788) 30 min before an antigen aerosol challenge. After 24 h, dose response curves to methacholine were performed in isolated lungs, FACS analysis of lymphocytes and eosinophil counts were performed in bronchoalveolar lavage fluid and mucus index was determined by histopathology. In sensitized and antigen-challenged mice there is a marked increase in the T CD4+, T CD8+, B220+, Tgammadelta+ and NK1.1+ lymphocyte subsets. Treatment with BQ123 further increased these cell populations. The number of eosinophils, airway hyperreactivity and mucus were all reduced by BQ123 treatment. The BQ 788 had no significant effect on the parameters analyzed. Treatment with BQ123 reduced the endothelin concentration in lung homogenates, suggesting that endothelins exert a positive feedback on their synthesis. We show here that in murine asthma the ETA receptor antagonist up-regulates lymphocyte infiltration and reduces eosinophils, hyperreactivity and mucus.

Small bowel injury associated to allergy is triggered by platelet-activating factor, mast cells, neutrophils and protected by nitric oxide.

Allergy to components of the diet is followed by gut inflammation which in children, sometimes progress to mucosal lesions and anaphylaxis. In newborns suffering of cow's milk allergy, bloody stools, rectal bleeding and ulcerations are found. The rat systemic anaphylaxis is a suitable model to study the intestinal lesions associated to allergy. In the present study we used this model to investigate some mechanisms involved. We found that 15 min after antigen challenge of sensitized rats, hemorrhagic lesions develop in the small intestine. The lesions were more severe in jejunum and ileum compared to duodenum. Pretreatment of the rats with a platelet-activating factor-receptor antagonist (WEB-2170) reduced the lesions whereas inhibition of endogenous nitric oxide by l-NAME, greatly increased the hemorrhagic lesions and mortality. Both, lesions and mortality were reversed by l-arginine. The hemorrhagic lesions were also significantly reduced by the mast cell stabilizers, disodium cromoglycate and ketotifen as well as by neutrophils depletion (with anti-PMN antibodies) or inhibition of selectin binding (by treatment with fucoidan). Thus, the intestinal hemorrhagic lesions in this model are dependent on platelet-activating factor, mast cell granule-derived mediators and neutrophils. Endogenous nitric oxide and supplementation with l-arginine has a protective role, reducing the lesions and preventing mortality. These results contributed to elucidate mechanisms involved in intestinal lesions which could be of relevance to human small bowel injury associated to allergy.

Modulation of lung allergic inflammation and malnutrition.

Nutritional deficiency is commonly associated with a significantly impaired immune response, particularly in relation to cell-mediated immunity, the complement system, cytokine production and phagocyte function. However, there are few data on the consequences of nutritional deficiency in allergic diseases of the lung. In fact, malnutrition is the most common cause of immunodeficiency worldwide. Several studies have indicated that the incidence of alterations in lung functions can be associated with birth weight, specifically with maternal malnutrition, but data linking intrauterine undernutrition with allergic diseases of the lung are lacking. The purpose of this review is to associate malnutrition, including intrauterine malnutrition, with the establishment of immune responses and the development of lung allergic inflammation.

Influence of age on the development of immunological lung response in intrauterine undernourishment.

OBJECTIVE: We investigated the effect of intrauterine undernourishment on some features of asthma using a model of allergic lung inflammation in rats. The effects of age at which the rats were challenged (5 and 9 wk) were also evaluated. METHODS: Intrauterine undernourished offspring were obtained from dams that were fed 50% of the nourished diet of counterparts and were immunized at 5 and 9 wk of age. They were tested for immunoglobulin E anti-ova titers (by passive cutaneous anaphylaxis), cell count in the bronchoalveolar fluid, leukotriene concentration, airway reactivity, mucus production, and blood corticosterone and leptin concentrations 21 d after immunologic challenge. RESULTS: Intrauterine undernourishment significantly reduced the antigen-specific immunoglobulin E production, inflammatory cell infiltration into airways, mucus secretion, and production of leukotrienes B(4)/C(4) in the lungs in both age groups compared with respective nourished rats. The increased reactivity to methacholine that follows antigen challenge was not affected by intrauterine undernourishment. Corticosterone levels increased with age in the undernourished rats' offspring, but not in the nourished rats' offspring. Undernourished offspring already presented high levels of corticosterone before inflammatory stimulus and were not modified by antigen challenge. Leptin levels increased with challenge in the nourished rats but not in the undernourished rats and could not be related to corticosterone levels in the undernourished rats. CONCLUSION: Intrauterine undernourishment has a striking and age-dependent effect on the offspring, reducing lung allergic inflammation.

A comparative study of pathophysiological alterations in scorpionism induced by Tityus serrulatus and Tityus bahiensis venoms.

Scorpionism is a relevant public health problem in several countries in tropical and subtropical regions. In Brazil, Tityus serrulatus sting can induce acute lung injury in part as a consequence of inflammation. Despite the occurrence of other scorpions of Tityus genus in Brazilian scorpiofauna, the knowledge regarding pulmonary alterations is related to T. serrulatus venom (Tsv). Here we studied, comparatively, the pathophysiological changes in the rat airways envenomed by Tsv or T. bahiensis venom (Tbv), since both scorpions are involved in human accidents but with severe envenomations occurring when victims are stung by T. serrulatus. After intravenous injection of the venoms (200 µg/kg), both were able to induce Evans blue extravasation (in 30 min) into airways and increased protein extravasation into lungs at 4 and 24 h, but the magnitude of such events was higher in Tsv group. Hemorrhage (in 60 min) in the lungs was higher in Tbv group, while IL-1ß (at 1 h) and IL-6 (at 1 and 4 h) in lung homogenates were detected only in Tsv group. Four and 24 h after envenomation, myeloperoxidase activity in lung was equally augmented in the envenomed groups, as well as an increased in polymorphonuclear cell numbers in bronchoalveolar lavage fluid. At 4 h blood leukogram showed increased leukocyte values with the highest neutrophilia in Tsv group. The numbers of leukocytes and neutrophils remained higher than control at 24 h in Tsv and Tbv groups, and it was accompanied by lympho (envenomed groups) and monocytosis (Tsv group). In conclusion, although Tbv was capable of inducing acute lung injury and blood leukocyte mobilization, most of the evaluated parameters were more affected by the Tsv. These results could help to explain the pathophysiology of the scorpionism and the clinical data arguing toward the greatest severity associated with T. serrulatus stings.