André Luis Lacerda Bachi

B-1 cells modulate the kinetics of wound-healing process in mice☆

Wound healing is a complex phenomenon whose mechanisms are not fully understood. Although inflammatory cells are recruited to the site of the lesion there are no reports concerning the participation of B lymphocytes in tissue repair. As demonstrated in our laboratory, B-1 cells migrate to a non-specific inflammatory focus and differentiate into a phagocyte. It has been reported that BALB/Xid mice are deficient in B-1 cells. Using this model, here we report that BALB/Xid mice have an increased inflammatory response, a delayed wound-healing process, a prominent neutrophilic infiltration of the lesion, and an increased neovascularization of the lesion as compared with BALB/c and BALB/Xid reconstituted with B-1 cells. The infiltration of B-1 cells into the wound was demonstrated. As B-1 cells secret and use interleukin 10 (IL-10) as an autocrine growth factor, the possible participation of this interleukin in the kinetics of wound healing was investigated. Results show that C57/BL6 IL-10 KO mice had an increased inflammatory response when compared with C57/BL6 and C57/BL6 IL-10 KO mice reconstituted with B-1 cells, thus suggesting that the observed effects of B-1 cells in the healing process is mediated by this interleukin. However, the mechanisms by which IL-10 influence these phenomena remain to be uncovered.

Leukotriene B4 creates a favorable microenvironment for murine melanoma growth.

Chronic inflammation has long been associated with neoplastic progression. Our group had recently shown that the addition of a large number of apoptotic tumor cells to the tumor microenvironment induces a potent acute inflammatory reaction capable of promoting melanoma growth; however, primarily necrotizing cells do not cause such a reaction. Here, we show that potent inflammatory agents, such as lipopolysaccharide (LPS) and carrageenan, also promote growth of subtumorigenic doses of melanoma cells, having no effect on melanoma proliferation in vitro. Inhibition of 5-lipoxygenase (5-LOX) seems to have a pivotal role in this model because caffeic acid and MK886, a FLAP (5-LOX–activating protein) inhibitor, partially hindered tumor growth induced by apoptotic cells or LPS. Other enzymes of the arachidonic acid pathway, cyclooxygenase-1 and cyclooxygenase-2, seem to have no participation in this tumor promoter effect, as the inhibitor of both enzymes (indomethacin) did not alter melanoma growth. Leukotriene B4 (LTB4), the main product of the 5-LOX pathway, was able to induce growth of subtumorigenic inocula of melanoma cells, and a LTB4 receptor antagonist inhibited acute inflammation-associated tumor growth. Addition to the tumor inflammatory microenvironment of eicosapentaenoic acid, an ω3-polyunsaturated fatty acid with anti-inflammatory properties, or leukotriene B5, an eicosapentaenoic acid–derived leukotriene, significantly inhibited tumor development. These results give new insights to the mechanisms through which inflammation may contribute to tumor progression and suggest that LOX has an important role in tumor progression associated with an inflammatory state in the presence of apoptosis, which may be a consideration for apoptosis-inducing treatments, such as chemotherapy and radiotherapy. (Mol Cancer Res 2009;7(9):1417–24)

Increased production of autoantibodies and specific antibodies in response to influenza virus vaccination in physically active older individuals

Immunosenescence is associated to aging and among many changes in immune response is reported a reduced response to vaccination and an increase in the number of cases of autoimmunity, caused by autoantibodies known as natural antibodies whose function, according to reports, would be protection against infection and inflammation. Although immunosenescence is an irreversible process, regular moderate exercise can attenuate some aspects of the decline in the immune system. So, the aim of this study was to investigate the humoral immune response in physically active elderly individuals before and 30 days after vaccination against influenza virus. The results showed that the percentage of individuals positive for antinuclear antibodies and serum immunoglobulin M and G levels after vaccination were higher in the group that exercised regularly than in the sedentary group. We were also able to demonstrate a significant correlation between levels of natural autoantibodies and response to vaccination.

Apoptotic Cells Contribute to Melanoma Progression and This Effect is Partially Mediated by the Platelet-Activating Factor Receptor

There is evidence that the platelet-activating factor receptor (PAFR) is involved in the clearance of apoptotic cells by macrophages, and that this is associated with anti-inflammatory phenotype. Our group has previously shown that coinjection of a large number of apoptotic cells can promote tumor growth from a subtumorigenic dose of melanoma cells. Here, we studied the involvement of the PAFR in the tumor growth promoting effect of apoptotic cells. A sub-tumorigenic dose of melanoma cells (Tm1) was coinjected with apoptotic Tm1 cells, subcutaneously in the flank of C57Bl/6 mice, and the volume was monitored for 30 days. Animals received the PAFR antagonists, WEB2170 or PCA4248 (5 mg/kg body weight) or vehicle, by peritumoral daily injection for 5 days. Results showed that PAFR antagonists significantly inhibited the tumor growth induced by the coinjection of a sub-tumorigenic dose of melanoma cells together with apoptotic cells. This was accompanied by inhibition of early neutrophil and macrophage infiltration. Addition of (platelet-activating factor) to this system has no significant effect. PAFR antagonists did not affect the promoting effect of carrageenan. We suggest that the recognition of apoptotic cells by phagocytes leads to activation of PAFR pathways, resulting in a microenvironment response favorable to melanoma growth.

Synthetic peptides mimic gp75 from Paracoccidioides brasiliensis in the diagnosis of paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is a systemic granulomatous disease, endemic in Latin America, caused by the thermal dimorphic fungus Paracoccidioides brasiliensis. Although some fungal antigens have already been characterized and used for serological diagnosis, cross-reactions have been frequently observed. Thus, the examination of fungal forms in clinical specimens or isolation of P. brasiliensis by culture is still the most frequent method for the diagnosis of this mycosis. In this study, a random peptide phage display library was used to select mimotopes of P. brasiliensis, which were employed as antigens in an indirect enzyme-linked immunosorbent assay. The protective monoclonal antibody against experimental PCM (anti-gp75) was used as molecular target to screen a phage display library. That approach led to a synthetic peptide named P2, which was synthesized and tested against PCM patients’ sera to check whether it was recognized. There was significant recognition of P2 by sera of untreated PCM patients when compared with normal human sera. Sera from treated PCM group, patients with other mycosis or co-infected with HIV had much lower recognition of P2 than untreated patient group. The test showed a sensitivity of 100 and 94.59% of specificity in relation to human sera control. These data indicate a potential use of P2 as diagnostic tool in PCM. Its application for serological diagnosis of PCM may contribute to the development and standardization of simpler, faster and highly reproducible immunodiagnostic tests at low cost.

Neuro-Immuno-Endocrine Modulation in Marathon Runners

Objective: Sports practice alters the homeostasis of athletes. To achieve homeostatic equilibrium, the integrated action of the neuroendocrine and immune systems is necessary. Here we studied the relation between cytokines, hormones and mood states in marathon runners. Methods: A total of 20 male recreational marathon runners (mean age = 35.7 ± 9 years) and 20 male sedentary individuals (mean age = 35.5 ± 7 years) were recruited. We compared the serum levels of growth hormone (GH), cortisol and interleukins 8 and 10 and the amounts of these two cytokines spontaneously produced by peripheral blood mononuclear cells. Blood samples of the sedentary group were collected at rest. Blood from the marathon runners was collected at rest (baseline: 24 h before the race), immediately after a marathon and 72 h after a marathon. Mood state analysis in both groups was performed using the 24-item Brunel Mood Scale (BRUMS). Results: Our results showed that, at rest, levels of interleukins 8 and 10 in the supernatant of culture cells, the serum concentration of GH, and tension and vigour (evaluated using the BRUMS), were significantly higher in athletes compared to sedentary people. Immediately after the race all serum parameters analysed were statistically higher than baseline values. At 72 h after the marathon, serum levels of hormones and interleukins returned to values at rest, but the concentrations of interleukins in the supernatant of culture cells showed a significant reduction compared to values at rest. Conclusion: The higher serum levels of GH in athletes at rest and the higher production of cytokines in culture without previous stimulus suggest that marathon runners present mechanisms that may be associated with preparing the body to perform prolonged strenuous exercise, such as a marathon.

Anticonvulsant activity of bone marrow cells in electroconvulsive seizures in mice.

BackgroundBone marrow is an accessible source of progenitor cells, which have been investigated as treatment for neurological diseases in a number of clinical trials. Here we evaluated the potential benefit of bone marrow cells in protecting against convulsive seizures induced by maximum electroconvulsive shock (MES), a widely used model for screening of anti-epileptic drugs. Behavioral and inflammatory responses were measured after MES induction in order to verify the effects promoted by transplantation of bone marrow cells. To assess the anticonvulsant effects of bone marrow cell transplantation, we measured the frequency and duration of tonic seizure, the mortality rate, the microglial expression and the blood levels of cytokine IL-1, IL-6, IL-10 and TNF-α after MES induction. We hypothesized that these behavioral and inflammatory responses to a strong stimulus such as a convulsive seizure could be modified by the transplantation of bone marrow cells.ResultsBone marrow transplanted cells altered the convulsive threshold and showed anticonvulsant effect by protecting from tonic seizures. Bone marrow cells modified the microglial expression in the analyzed brain areas, increased the IL-10 and attenuate IL-6 levels.ConclusionsBone marrow cells exert protective effects by blocking the course of electroconvulsive seizures. Additionally, electroconvulsive seizures induced acute inflammatory responses by altering the pattern of microglia expression, as well as in IL-6 and IL-10 levels. Our findings also indicated that the anticonvulsant effects of these cells can be tested with the MES model following the same paradigm used for drug testing in pharmacological screening. Studies on the inflammatory reaction in response to acute seizures in the presence of transplanted bone marrow cells might open a wide range of discussions on the mechanisms relevant to the pathophysiology of epilepsies.

Exercise Training Improves Plasma Lipid and Inflammatory Profiles and Increases Cholesterol Transfer to High-Density Lipoprotein in Elderly Women

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Bone: the final frontier for Staphylococcus aureus penetration in chronic rhinosinusitis.

AbstractThe superantigenic properties of Staphylococcus aureus have been implicated in increasing the inflammatory process in airway diseases. Local formation of IgE antibodies against staphylococcal enterotoxins by secondary lymphoid tissue in nasal polyps has been demonstrated. Staphylococcus aureus is known to colonize the nasal mucosa, and has been found invading the nasal submucosa and intracellularly.ObjectiveTo evaluate the limits of Staphylococcus aureus invasion in the upper airway.Material and methodsInferior turbinate samples from 3 patients without sinus disease, 6 ethmoid samples from patients with chronic rhinosinusitis with nasal polyposis, and 6 ethmoid samples from patients with chronic rhinosinusitis without nasal polyposis were studied. A fluorescein-labeled PNA probe against Staphylococcus aureus was used to test for the presence of the bacterium in bone (after decalcification) and mucosa.ResultsWe found Staphylococcus aureus invading the nasal submucosa in patients with nasal polyposis, but no cases of Staphylococcus aureus positivity in bone. In conclusion, we cannot support the hypothesis of nasal bone as a reservoir for Staphylococcus aureus, releasing massive amounts of staphylococcal enterotoxins and eliciting an inflammatory reaction, as occurs with the nasal mucosa.

Relationship between Anxiety and Interleukin 10 in Female Soccer Players with and Without Premenstrual Syndrome (PMS)

Objective To investigate the level of anxiety and its relationship with interleukin (IL)-10 (anti inflammatory cytokine that modulates mood swings) in a group of female soccer players. Methods Fifty-two eumenorrheic soccer players were evaluated (age 19.8 ± 4.7 years). The presence of premenstrual syndrome (PMS) and phases of the menstrual cycle were determined by a daily symptom report (DSR) kept for 3 consecutive months. The concentration of cytokine IL-10 was determined from urine samples collected at four moments: at the follicular and luteal phases of the menstrual cycle, and before (pre) and after (post) the simulated game, and it was quantified by flow cytometry (Luminex xMAP - EMD Millipore, Billerica, MA, USA). The level of anxiety was determined through the BAI anxiety questionnaire answered by all athletes at the same time of the urine collection. The Student t-test, analysis of variance (ANOVA) and Pearson correlation with significance level at 5% were used for data analysis. Results We showed that the prevalence of PMS among female soccer players is similar to that reported in the literature. In addition, we showed that the group with PMS has a higher level of anxiety compared with group without PMS (p = 0.002). Interleukin-10 analysis in players without PMS revealed that there was a significant decrease in the level of this cytokine before the game during the luteal phase when compared with the follicular phase (p < 0.05). The correlation analysis between IL-10 and anxiety showed a negative correlation post-game in the luteal phase in the group without PMS (p = 0.02; r = -0.50) and a positive correlation post-game in the luteal phase in PMS group (p = 0.04; r = 0.36). Conclusion Our results suggest that IL-10 may contribute to reduce anxiety in the group without PMS. This could be attributed to the fact that no IL-10 variation was observed in the group with PMS, which presented higher anxiety symptoms when compared with the group without PMS.