Adriano L.S. Souza

B vitamins induce an antinociceptive effect in the acetic acid and formaldehyde models of nociception in mice.

The effect of some B vitamins in chemical and thermal models of nociception in mice was investigated. The association thiamine/pyridoxine/cyanocobalamin (TPC, 20-200 mg/kg, i.p. or per os), thiamine, pyridoxine (50-200 mg/kg, i.p.) or riboflavin (3-100 mg/kg, i.p) induced an antinociceptive effect, not changed by naloxone (10 mg/kg, i.p.), in the acetic acid writhing model. Treatment for 7 days with thiamine/pyridoxine/cyanocobalamin (100 or 200 mg/kg, i.p.), thiamine (50 or 100 mg/kg) or pyridoxine (50 or 100 mg/kg) or acute treatment with riboflavin (6 or 12 mg/kg, i.p) inhibited the nociceptive response induced by formaldehyde. The B vitamins did not inhibit the nociceptive response in the hot-plate model. Both 7-day thiamine/pyridoxine/cyanocobalamin (100 mg/kg, i.p.) or acute riboflavin (25 or 50 mg/kg, i.p.) treatment partially reduced formaldehyde-induced hindpaw oedema. The B vitamins antinociceptive effect may involve inhibition of the synthesis and/or action of inflammatory mediators since it was not observed in the hot-plate model, was not reversed by naloxone, only the second phase of the formaldehyde-induced nociceptive response was inhibited, and formaldehyde-induced hindpaw oedema was reduced.

Essential role of platelet-activating factor receptor in the pathogenesis of Dengue virus infection

Severe dengue infection in humans causes a disease characterized by thrombocytopenia, increased levels of cytokines, increased vascular permeability, hemorrhage, and shock. Treatment is supportive. Activation of platelet-activating factor (PAF) receptor (PAFR) on endothelial cells and leukocytes induces increase in vascular permeability, hypotension, and production of cytokines. We hypothesized that activation of PAFR could account for the major systemic manifestations of dengue infection. Inoculation of adult mice with an adapted strain of Dengue virus caused a systemic disease, with several features of the infection in humans. In PAFR−/− mice, there was decreased thrombocytopenia, hemoconcentration, decreased systemic levels of cytokines, and delay of lethality, when compared with WT infected mice. Treatment with UK-74,505, an orally active PAFR antagonist, prevented the above-mentioned manifestations, as well as hypotension and increased vascular permeability, and decreased lethality, even when started 5 days after virus inoculation. Similar results were obtained with a distinct PAFR antagonist, PCA-4246. Despite decreased disease manifestation, viral loads were similar (PAFR−/−) or lower (PAFR antagonist) than in WT mice. Thus, activation of PAFR plays a major role in the pathogenesis of experimental dengue infection, and its blockade prevents more severe disease manifestation after infection with no increase in systemic viral titers, suggesting that there is no interference in the ability of the murine host to deal with the infection. PAFR antagonists are disease-modifying agents in experimental dengue infection.

Role of the Chemokine Receptor CXCR2 in Bleomycin-Induced Pulmonary Inflammation and Fibrosis

Pulmonary fibrosis is characterized by chronic inflammation and excessive collagen deposition. Neutrophils are thought to be involved in the pathogenesis of lung fibrosis. We hypothesized that CXCR2-mediated neutrophil recruitment is essential for the cascade of events leading to bleomycin-induced pulmonary fibrosis. CXCL1/KC was detected as early as 6 hours after bleomycin instillation and returned to basal levels after Day 8. Neutrophils were detected in bronchoalveolar lavage and interstitium from 12 hours and peaked at Day 8 after instillation. Treatment with the CXCR2 receptor antagonist, DF2162, reduced airway neutrophil transmigration but led to an increase of neutrophils in lung parenchyma. There was a significant reduction in IL-13, IL-10, CCL5/RANTES, and active transforming growth factor (TGF)-beta(1) levels, but not on IFN-gamma and total TGF-beta(1,) and enhanced granulocyte macrophage-colony-stimulating factor production in DF2162-treated animals. Notably, treatment with the CXCR2 antagonist led to an improvement of the lung pathology and reduced collagen deposition. Using a therapeutic schedule, DF2162 administered from Days 8 to 16 after bleomycin reduced pulmonary fibrosis and levels of active TGF-beta(1) and IL-13. DF2162 treatment reduced bleomycin-induced expression of von Willebrand Factor, a marker of angiogenesis, in the lung. In vitro, DF2162 reduced the angiogenic activity of IL-8 on human umbilical vein endothelial cells. In conclusion, we show that CXCR2 plays an important role in mediating fibrosis after bleomycin instillation. The compound blocks angiogenesis and the production of pro-angiogenic cytokines, and decreases IL-8-induced endothelial cell activation. An effect on neutrophils does not appear to account for the major effects of the blockade of CXCR2 in the system.

Norepinephrine, dopamine and dexamethasone modulate discrete leukocyte subpopulations and cytokine profiles from human PBMC

The interplay between the immune and neuroendocrine systems is intense, with the cross-talk between these two systems increasing during stress circumstances. Stress events culminate with hormonal pathway activation elevating the plasma levels of glucocorticoids and catecholamines. The majority of the works evaluating the effects of stress hormones on immune cells have utilized in vivo animal models or clinical studies. This work evaluates the effects of norepinephrine, dopamine, dexamethasone, and the combination of norepinephrine and dexamethasone on cellular activation and expression of immunoregulatory cytokines and chemokines by human PBMC in vitro. Norepinephrine and dopamine increased lymphocyte activation accompanied by augmented Th1 and Th2 type cytokine production. Dexamethasone reduced cell activation and decreased frequencies of cytokine producing cells and chemokine production. The action of norepinephrine together with dexamethasone resulted in immunosupression. The observed effects of hormones and neurotransmitters on leukocyte subsets likely underlie their immunomodulatory action in vivo.

In vivo evidence for a role of protein kinase C in peripheral nociceptive processing

The present study was designed to characterize the nociceptive response induced by protein kinase C (PKC) peripheral activation and to investigate if this biochemical event is important for the nociceptive response induced by formaldehyde, and bradykinin (BK). Intraplantar injection of phorbol‐12,13‐didecanoate (PDD; 0.01, 0.1 or 1 μg), a PKC activator, but not of 4α‐PDD (inactive analogue), dose‐dependently induced thermal hyperalgesia in rats. This response was not observed at the contralateral hindpaw. Intraplantar injection of PDD (0.01, 0.1 or 1 μg) also induced mechanical allodynia. In mice, injection of PDD (0.1 or 1 μg) into the dorsum of the hindpaw induced a spontaneous licking behaviour. Intraplantar co‐injection of chelerythrine (10 or 50 μg), a PKC inhibitor, attenuated the thermal hyperalgesia induced by PDD (0.1 μg) in rats. The second phase of the nociceptive response induced by the injection of formaldehyde (0.92%, 20 μl) into the dorsum of mice hindpaws was inhibited by ipsi‐, but not contralateral, pre‐treatment with chelerythrine (1 μg). Intraplantar injection of BK (10 μg) induced mechanical allodynia in rats. Ipsi‐ but not contralateral injection of bisindolylmaleimide I (10 μg), a PKC inhibitor, inhibited BK‐induced mechanical allodynia. In conclusion, this study demonstrates that PKC activation at peripheral tissues leads to the development of spontaneous nociceptive response, thermal hyperalgesia and mechanical allodynia. Most importantly, it also gives in vivo evidence that peripheral PKC activation is essential for the full establishment of the nociceptive response induced by two different inflammatory stimuli.

ST2, an IL‐1R family member, attenuates inflammation and lethality after intestinal ischemia and reperfusion

Ischemia reperfusion injury is characterized by local and systemic inflammation leading to considerable mortality. Previously, we have reported that soluble T1/ST2 (sST2), a member of the IL‐1 receptor gene family, inhibits LPS‐induced macrophage proinflammatory cytokine production. Here, we report the therapeutic effect of sST2‐Fc in a murine model of intestinal ischemia reperfusion‐induced injury. Administration of sST2‐Fc fusion protein i.v., 10 min before reperfusion, reduced the production of TNF‐α dose‐dependently in the intestine and in the lungs. The sST2‐Fc treatment with the highest dose (100 μg) resulted in inhibited vascular permeability, neutrophilia, and hemorrhage in the intestine and the lungs compared with controls treated with normal IgG. This was associated with down‐regulated tissue levels of proinflammatory cytokines, markedly reduced serum TNF‐α levels, and increased survival of mice from the sST2‐Fc‐treated group after ischemia and reperfusion injury. The beneficial effect of sST2‐Fc treatment was associated with elevated IL‐10 production in intestine and lung. sST2‐Fc was not able to prevent the inflammatory response associated with intestinal ischemia and reperfusion in IL‐10‐deficient mice, suggesting that sST2 exerts its anti‐inflammatory effect in a IL‐10‐dependent manner. These results also demonstrate that sST2‐Fc may provide a novel, complementary approach in treating ischemic reperfusion injury.

Increased serum concentrations of monokine induced by interferon-γ/CXCL9 and interferon-γ-inducible protein 10/CXCL-10 in Sydenham's chorea patients

Sydenhams chorea (SC) is thought to result from the action of streptococcus-induced antibodies that cross react with basal ganglia antigens. Much less is known, however, about the involvement of cellular mechanisms in its pathogenesis. Since chemokines seem to play a role in several CNS inflammatory disorders, we sought to investigate the chemokine profile of patients with SC. Increased serum levels of CXCL9, formerly monokine induced by interferon-gamma (Mig), and CXCL10, formerly interferon-gamma-inducible protein of 10 kDa (IP-10) were demonstrated in acute SC patients, suggesting that a particular group of chemokines may be involved in SC pathogenesis.

Role of the chemokines CCL3/MIP-1α and CCL5/RANTES in sponge-induced inflammatory angiogenesis in mice

OBJECTIVE We examined the potential contribution of CCL3 and CCL5 to inflammatory angiogenesis in mice. METHODS Polyester-polyurethane sponges were implanted in mice and blood vessel counting and hemoglobin, myeloperoxidase and N-acetylglucosaminidase measurements used as indexes for vascularization, neutrophil and macrophage accumulation, respectively. RESULTS CCL3 and CCL5 were expressed throughout the observation period. Exogenous CCL3 enhanced angiogenesis in WT, but angiogenesis proceeded normally in CCL3(-/-) mice, suggesting that endogenous CCL3 is not critical for sponge-induced angiogenesis in mice. CCL5 expression was detected at day 1, but levels significantly increased thereafter. Exogenous CCL5 reduced angiogenesis in WT mice possible via CCR5 as CCL5 was without an effect in CCR5(-/-) mice. Treatment of WT with the CCR1/CCR5 antagonist, Met-RANTES, prevented neutrophil and macrophage accumulation, but enhanced sponge vascularization. CONCLUSION Thus, endogenous CCL3 appears not to play a role in driving sponge-induced inflammatory angiogenesis in mice. The effects of CCL5 were anti-angiogenic and appeared to be mediated via activation of CCR5.

A QSERR study on enantioselective separation of enantiomeric sulphoxides

A set of chiral sulphoxides was chromatographed on four chiral stationary phases (CSPs), using cellulose and amylose tris-phenylcarbamates coated onto 3-aminopropyl mesoporous silica. The relative retention and enantioselectives of the solutes were compared to molecular connectivity indices, similarity and holistic descriptors calculated by 3D-WHIM. Many quantitative structure-enantioselective retention relationships were developed to describe the enantioselective chromatographic performance. The same dataset was used for all CSPs, and it was possible to reveal a clear distinction between them, i.e. there was a molecular recognition pattern established according to CSPs. Results also showed that log k could be predicted for both sulphoxide enantiomers, but α was not discriminated.

Serum and cerebral spinal fluid levels of chemokines and Th2 cytokines in Schistosoma mansoni myeloradiculopathy

Schistosomal myeloradiculopathy (SMR) is the most common neurological form of Schistosoma mansoni infection. In this study we investigated the expression of chemokines and Th2 cytokines in serum and cerebral spinal fluid (CSF) of SMR patients. SMR patients presented increased serum levels of CCL11/eotaxin and CCL24/eotaxin‐2 when compared to controls. SMR patients also had higher levels of IL‐13 in CSF. Thus, SMR patients present enhancement of both IL‐13 and CCR3 acting chemokines, both of which may facilitate the expression of a Th2 response and Th2‐dependent damage to the spinal cord. As this cytokine is responsible for promoting Th2 responses, this finding is in accordance to the view that Th2 cells are important in the immunological process against the S. mansoni.