Cannabidiol protects oligodendrocyte progenitor cells from inflammation-induced apoptosis by attenuating endoplasmic reticulum stress

Cannabidiol (CBD) is the most abundant cannabinoid in Cannabis sativa that has no psychoactive properties. CBD has been approved to treat inflammation, pain and spasticity associated with multiple sclerosis (MS), of which demyelination and oligodendrocyte loss are hallmarks. Thus, we investigated the protective effects of CBD against the damage to oligodendrocyte progenitor cells (OPCs) mediated by the immune system. Doses of 1 mu M CBD protect OPCs from oxidative stress by decreasing the production of reactive oxygen species. CBD also protects OPCs from apoptosis induced by LPS/IFN gamma through the decrease of caspase 3 induction via mechanisms that do not involve CB1, CB2, TRPV1 or PPAR gamma receptors. Tunicamycin-induced OPC death was attenuated by CBD, suggesting a role of endoplasmic reticulum (ER) stress in the mode of action of CBD. This protection against ER stress-induced apoptosis was associated with reduced phosphorylation of eiF2 alpha, one of the initiators of the ER stress pathway. Indeed, CBD diminished the phosphorylation of PKR and eiF2 alpha induced by LPS/IFN gamma. The pro-survival effects of CBD in OPCs were accompanied by decreases in the expression of ER apoptotic effectors (CHOP, Bax and caspase 12), and increased expression of the anti-apoptotic Bcl-2. These findings suggest that attenuation of the ER stress pathway is involved in the 'oligoprotective' effects of CBD during inflammation. Cell Death and Disease (2012) 3, e331; doi:10.1038/cddis.2012.71; published online 28 June 2012

Titanium dioxide induced inflammation in the small intestine

AIM: To investigate the effects of titanium dioxide (TiO2) nanoparticles (NPTiO2) and microparticles (MPTiO2) on the inflammatory response in the small intestine of mice. METHODS: BI 57/6 male mice received distilled water suspensions containing TiO2 (100 mg/kg body weight) as NPTiO2 (66 nm), or MPTiO2 (260 nm) by gavage for 10 d, once a day; the control group received only distilled water. At the end of the treatment the duodenum, jejunum and ileum were extracted for assessment of cytokines, inflammatory cells and titanium content. The cytokines interleukin (IL)-1b, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, IL-17, IL-23, tumor necrosis factor-alpha (TNF-alpha), intracellular interferon-gamma (IFN-gamma) and transforming growth factor-beta (TGF-beta) were evaluated by enzyme-linked immunosorbent assay in segments of jejunum and ileum (mucosa and underlying muscular tissue). CD4(+) and CD8(+) T cells, natural killer cells, and dendritic cells were evaluated in duodenum, jejunum and ileum samples fixed in 10% formalin by immunohistochemistry. The titanium content was determined by inductively coupled plasma atomic emission spectrometry. RESULTS: We found increased levels of T CD4(+) cells (cells/mm(2)) in duodenum: NP 1240 +/- 139.4, MP 1070 +/- 154.7 vs 458 +/- 50.39 (P < 0.01); jejunum: NP 908.4 +/- 130.3, MP 813.8 +/- 103.8 vs 526.6 +/- 61.43 (P < 0.05); and ileum: NP 818.60 +/- 123.0, MP 640.1 +/- 32.75 vs 466.9 +/- 22.4 (P < 0.05). In comparison to the control group, the groups receiving TiO2 showed a statistically significant increase in the levels of the inflammatory cytokines IL-12, IL-4, IL-23, TNF-alpha, IFN-gamma and TGF-beta. The cytokine production was more pronounced in the ileum (mean SE): IL-12: NP 33.98 +/- 11.76, MP 74.11 +/- 25.65 vs 19.06 +/- 3.92 (P < 0.05); IL-4: NP 17.36 +/- 9.96, MP 22.94 +/- 7.47 vs 2.19 +/- 0.65 (P < 0.05); IL-23: NP 157.20 +/- 75.80, MP 134.50 +/- 38.31 vs 22.34 +/- 5.81 (P < 0.05); TNF alpha: NP 3.71 +/- 1.33, MP 5.44 +/- 1.67 vs 0.99 +/- 019 (P < 0.05); IFN gamma: NP 15.85 +/- 9.99, MP 34.08 +/- 11.44 vs 2.81 +/- 0.69 (P < 0.05); and TGF-alpha: NP 780.70 +/- 318.50, MP 1409.00 +/- 502.20 vs 205.50 +/- 63.93 (P < 0.05). CONCLUSION: Our findings indicate that TiO2 particles induce a Th1-mediated inflammatory response in the small bowel in mice. (C) 2012 Baishideng. All rights reserved.

Altered Oxygen Metabolism Associated to Neurogenesis of Induced Pluripotent Stem Cells Derived From a Schizophrenic Patient

Schizophrenia has been defined as a neurodevelopmental disease that causes changes in the process of thoughts, perceptions. and emotions, usually leading to a mental deterioration and affective blunting. Studies have shown altered cell respiration and oxidative stress response in schizophrenia; however, most of the knowledge has been acquired from postmortem brain analyses or from nonneural cells. Here we describe that neural cells, derived from induced pluripotent stem cells generated from skin fibroblasts of a schizophrenic patient, presented a twofold increase in extramitochondrial oxygen consumption as well as elevated levels of reactive oxygen species (ROS), when compared to controls. This difference in ROS levels was reverted by the mood stabilizer valproic acid. Our model shows evidence that metabolic changes occurring during neurogenesis are associated with schizophrenia, contributing to a better understanding of the development of the disease and highlighting potential targets for treatment and drug screening.

Bosentan, an endothelin receptor antagonist, ameliorates collagen-induced arthritis: the role of TNF-alpha in the induction of endothelin system genes

Endothelins (ETs) are involved in several inflammatory events. The present study investigated the efficacy of bosentan, a dual ETA/ETB receptor antagonist, in collagen-induced arthritis (CIA) in mice. CIA was induced in DBA/1J mice. Arthritic mice were treated with bosentan (100 mg/kg) once a day, starting from the day when arthritis was clinically detectable. CIA progression was assessed by measurements of visual clinical score, paw swelling and hypernociception. Histological changes, neutrophil infiltration and pro-inflammatory cytokines were evaluated in the joints. Gene expression in the lymph nodes of arthritic mice was evaluated by microarray technology. PreproET-1 mRNA expression in the lymph nodes of mice and in peripheral blood mononuclear cells (PBMCs) was evaluated by real-time PCR. The differences were evaluated by one-way ANOVA or Student's t test. Oral treatment with bosentan markedly ameliorated the clinical aspects of CIA (visual clinical score, paw swelling and hyperalgesia). Bosentan treatment also reduced joint damage, leukocyte infiltration and pro-inflammatory cytokine levels (IL-1 beta, TNF alpha and IL-17) in the joint tissues. Changes in gene expression in the lymph nodes of arthritic mice returned to the levels of the control mice after bosentan treatment. PreproET mRNA expression increased in PBMCs from rheumatoid arthritis (RA) patients but returned to basal level in PBMCs from patients under anti-TNF therapy. In-vitro treatment of PBMCs with TNF alpha upregulated ET system genes. These findings indicate that ET receptor antagonists, such as bosentan, might be useful in controlling RA. Moreover, it seems that ET mediation of arthritis is triggered by TNF alpha.

The Natural Cell-Penetrating Peptide Crotamine Targets Tumor Tissue in Vivo and Triggers a Lethal Calcium-Dependent Pathway in Cultured Cells

Our goal was to demonstrate the in vivo tumor specific accumulation of crotamine, a natural peptide from the venom of the South American rattlesnake Crotalus durissus terrificus, which has been characterized by our group as a cell penetrating peptide with a high specificity for actively proliferating cells and with a concentration-dependent cytotoxic effect. Crotamine cytotoxicity has been shown to be dependent on the disruption of lysosomes and subsequent activation of intracellular proteases. In this work, we show that the cytotoxic effect of crotamine also involves rapid intracellular calcium release and loss of mitochondrial membrane potential as observed in real time by confocal microscopy. The intracellular calcium overload induced by crotamine was almost completely blocked by thapsigargin. Microfluorimetry assays confirmed the importance of internal organelles, such as lysosomes and the endoplasmic reticulum, as contributors for the intracellular calcium increase, as well as the extracellular medium. Finally, we demonstrate here that crotamine injected intraperitoneally can efficiently target remote subcutaneous tumors engrafted in nude mice, as demonstrated by a noninvasive optical imaging procedure that permits in vivo real-time monitoring of crotamine uptake into tumor tissue. Taken together, our data indicate that the cytotoxic peptide crotamine can be used potentially for a dual purpose: to target and detect growing tumor tissues and to selectively trigger tumor cell death.

Impaired beta-adrenoceptor-induced relaxation in small mesenteric arteries from DOCA-salt hypertensive rats is due to reduced K-Ca channel activity

beta-Adrenoceptor (beta-AR)-mediated relaxation plays an important role in the regulation of vascular tone. beta-AR-mediated vascular relaxation is reduced in various disease states and aging. We hypothesized that beta-AR-mediated vasodilatation is impaired in DOCA-salt hypertension due to alterations in the cAMP pathway. beta-AR-mediated relaxation was determined in small mesenteric arteries from DOCA-salt hypertensive and control uninephrectomized (Uni) rats. To exclude nitric oxide (NO) and cyclooxygenase (COX) pathways, relaxation responses were determined in the presence of L-NNA and indomethacin, NO synthase inhibitor and COX inhibitors, respectively. Isoprenaline (ISO)-induced relaxation was reduced in arteries from DOCA-salt compared to Uni rats. Protein kinase A (PKA) inhibitors (H89 or Rp-cAMPS) or adenylyl cyclase inhibitor (SQ22536) did not abolish the difference in ISO-induced relaxation between the groups. Forskolin (adenylyl cyclase activator)-induced relaxation was similar between the groups. The inhibition of IKCa/SKCa channels (TRAM-34 plus UCL1684) or BKCa channels (iberiotoxin) reduced ISO-induced relaxation only in Uni rats and abolished the relaxation differences between the groups. The expression of SKCa channel was decreased in DOCA-salt arteries. The expression of BKCa channel a subunit was increased whereas the expression of BKCa channel p subunit was decreased in DOCA-salt arteries. The expression of receptor for activated C kinase 1 (RACK1), which is a binding protein for BKG, channel and negatively modulates its activity, was increased in DOCA-salt arteries. These results suggest that the impairment of beta-AR-mediated relaxation in DOCA-salt mesenteric arteries may be attributable to altered IKCa/SKCa and/or BKCa channels activities rather than cAMP/PKA pathway. Impaired beta-AR-stimulated BKCa channel activity may be due to the imbalance between its subunit expressions and RACK1 upregulation. (C) 2012 Elsevier Ltd. All rights reserved.

Subthalamic deep brain stimulation modulates small fiber-dependent sensory thresholds in Parkinson's disease

The effects of deep brain stimulation of the subthalamic nucleus on nonmotor symptoms of Parkinson's disease (PD) rarely have been investigated. Among these, sensory disturbances, including chronic pain (CP), are frequent in these patients. The aim of this study was to evaluate the changes induced by deep brain stimulation in the perception of sensory stimuli, either noxious or innocuous, mediated by small or large nerve fibers. Sensory detection and pain thresholds were assessed in 25 PD patients all in the off-medication condition with the stimulator turned on or off (on- and off-stimulation conditions, respectively). The relationship between the changes induced by surgery on quantitative sensory testing, spontaneous CP, and motor abilities were studied. Quantitative sensory test results obtained in PD patients were compared with those of age-matched healthy subjects. Chronic pain was present in 72% of patients before vs 36% after surgery (P = .019). Compared with healthy subjects, PD patients had an increased sensitivity to innocuous thermal stimuli and mechanical pain, but a reduced sensitivity to innocuous mechanical stimuli. In addition, they had an increased pain rating when painful thermal stimuli were applied, particularly in the off-stimulation condition. In the on-stimulation condition, there was an increased sensitivity to innocuous thermal stimuli but a reduced sensitivity to mechanical or thermal pain. Pain provoked by thermal stimuli was reduced when the stimulator was turned on. Motor improvement positively correlated with changes in warm detection and heat pain thresholds. Subthalamic nucleus deep brain stimulation contributes to relieve pain associated with PD and specifically modulates small fiber-mediated sensations. (C) 2012 International Association for the Study of Pain. Published by Elsevier B. V. All rights reserved.

Schistosoma mansoni: In vitro schistosomicidal activity and tegumental alterations induced by piplartine on schistosomula

Schistosomiasis is one of the most important parasitic infections in humans that occur in many tropical and subtropical countries. Currently, the control of schistosomiasis rests with a single drug, praziquantel, which is effective against adult worms but not the larval stages. Recent studies have shown that piplartine, an amide isolated from plants of the genus Piper (Piperaceae), reveals interesting antischistosomal properties against Schistosoma mansoni adult worms. Here, we report the in vitro antischistosomal activity of piplartine on S. mansoni schistosomula of different ages (3 h old and 1, 3, 5, and 7 days old), and examine alterations on the tegumental surface of worms by means of confocal laser scanning microscopy. Piplartine at a concentration of 7.5 mu M caused the death of all schistosomula within 120 h. The lethal effect occurred in a dose-dependent manner and was also dependent on the age of the parasite. Microscopy observation revealed extensive tegumental destruction, including blebbing, granularity, and a shorter body length. This report provides the first evidence that piplartine is able to kill schistosomula of different ages and reinforce that piplartine is a promising compound that could be used for the development of new schistosomicidal agent. (c) 2012 Elsevier Inc. All rights reserved.

Application of magnetically induced hyperthermia in the model protozoan Crithidia fasciculata as a potential therapy against parasitic infections

Background: Magnetic hyperthermia is currently a clinical therapy approved in the European Union for treatment of tumor cells, and uses magnetic nanoparticles (MNPs) under time-varying magnetic fields (TVMFs). The same basic principle seems promising against trypanosomatids causing Chagas disease and sleeping sickness, given that the therapeutic drugs available have severe side effects and that there are drug-resistant strains. However, no applications of this strategy against protozoan-induced diseases have been reported so far. In the present study, Crithidia fasciculata, a widely used model for therapeutic strategies against pathogenic trypanosomatids, was targeted with Fe3O4 MNPs in order to provoke cell death remotely using TVMFs. Methods: Iron oxide MNPs with average diameters of approximately 30 nm were synthesized by precipitation of FeSO4 in basic medium. The MNPs were added to C. fasciculata choanomastigotes in the exponential phase and incubated overnight, removing excess MNPs using a DEAE-cellulose resin column. The amount of MNPs uploaded per cell was determined by magnetic measurement. The cells bearing MNPs were submitted to TVMFs using a homemade AC field applicator (f = 249 kHz, H = 13 kA/m), and the temperature variation during the experiments was measured. Scanning electron microscopy was used to assess morphological changes after the TVMF experiments. Cell viability was analyzed using an MTT colorimetric assay and flow cytometry. Results: MNPs were incorporated into the cells, with no noticeable cytotoxicity. When a TVMF was applied to cells bearing MNPs, massive cell death was induced via a nonapoptotic mechanism. No effects were observed by applying TVMF to control cells not loaded with MNPs. No macroscopic rise in temperature was observed in the extracellular medium during the experiments. Conclusion: As a proof of principle, these data indicate that intracellular hyperthermia is a suitable technology to induce death of protozoan parasites bearing MNPs. These findings expand the possibilities for new therapeutic strategies combating parasitic infection.

Characterization of Heparin-induced Glyceraldehyde-3-phosphate Dehydrogenase Early Amyloid-like Oligomers and Their Implication in alpha-Synuclein Aggregation

Lewy bodies and Lewy neurites, neuropathological hallmarks of several neurological diseases, are mainly made of filamentous assemblies of alpha-synuclein. However, other macromolecules including Tau, ubiquitin, glyceraldehyde-3-phosphate dehydrogenase, and glycosaminoglycans are routinely found associated with these amyloid deposits. Glyceraldehyde-3-phosphate dehydrogenase is a glycolytic enzyme that can form fibrillar aggregates in the presence of acidic membranes, but its role in Parkinson disease is still unknown. In this work, the ability of heparin to trigger the amyloid aggregation of this protein at physiological conditions of pH and temperature is demonstrated by infrared and fluorescence spectroscopy, dynamic light scattering, small angle x-ray scattering, circular dichroism, and fluorescence microscopy. Aggregation proceeds through the formation of short rod-like oligomers, which elongates in one dimension. Heparan sulfate was also capable of inducing glyceraldehyde-3-phosphate dehydrogenase aggregation, but chondroitin sulfates A, B, and C together with dextran sulfate had a negligible effect. Aided with molecular docking simulations, a putative binding site on the protein is proposed providing a rational explanation for the structural specificity of heparin and heparan sulfate. Finally, it is demonstrated that in vitro the early oligomers present in the glyceraldehyde-3-phosphate dehydrogenase fibrillation pathway promote alpha-synuclein aggregation. Taking into account the toxicity of alpha-synuclein prefibrillar species, the heparin-induced glyceraldehyde-3-phosphate dehydrogenase early oligomers might come in useful as a novel therapeutic strategy in Parkinson disease and other synucleinopathies.

Aerobic exercise attenuates pulmonary injury induced by exposure to cigarette smoke

It has recently been suggested that regular exercise reduces lung function decline and risk of chronic obstructive pulmonary disease (COPD) among active smokers; however, the mechanisms involved in this effect remain poorly understood. The present study evaluated the effects of regular exercise training in an experimental mouse model of chronic cigarette smoke exposure. Male C57BL/6 mice were divided into four groups (control, exercise, smoke and smoke+exercise). For 24 weeks, we measured respiratory mechanics, mean linear intercept, inflammatory cells and reactive oxygen species (ROS) in bronchoalveolar lavage (BAL) fluid, collagen deposition in alveolar walls, and the expression of antioxidant enzymes, matrix metalloproteinase 9, tissue inhibitor of metalloproteinase (TIMP) 1, interleukin (IL)-10 and 8-isoprostane in alveolar walls. Exercise attenuated the decrease in pulmonary elastance (p<0.01) and the increase in mean linear intercept (p=0.003) induced by cigarette smoke exposure. Exercise substantially inhibited the increase in ROS in BAL fluid and 8-isoprostane expression in lung tissue induced by cigarette smoke. In addition, exercise significantly inhibited the decreases in IL-10, TIMP1 and CuZn superoxide dismutase induced by exposure to cigarette smoke. Exercise also increased the number of cells expressing glutathione peroxidase. Our results suggest that regular aerobic physical training of moderate intensity attenuates the development of pulmonary disease induced by cigarette smoke exposure.

Diaphragmatic Breathing Training Program Improves Abdominal Motion During Natural Breathing in Patients With Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

Yamaguti WP, Claudino RC, Neto AP, Chammas MC, Gomes AC, Salge TM, Moriya HT, Cukier A, Carvalho CR. Diaphragmatic breathing training program improves abdominal motion during natural breathing in patients with chronic obstructive pulmonary disease: a randomized controlled trial. Arch Phys Med Rehabil 2012;93:571-7. Objective: To investigate the effects of a diaphragmatic breathing training program (DBTP) on thoracoabdominal motion and functional capacity in patients with chronic obstructive pulmonary disease. Design: A prospective, randomized controlled trial. Setting: Academic medical center. Participants: Subjects (N=30; forced expiratory volume in Is, 4270 +/- 13% predicted) were randomly allocated to either a training group (TG) or a control group (CG). Interventions: Subjects in the TG completed a 4-week supervised DBTP (3 individualized weekly sessions), while those in the CG received their usual care. Main Outcome Measures: Effectiveness was assessed by amplitude of the rib cage to abdominal motion ratio (RC/ABD ratio) (primary outcome) and diaphragmatic mobility (secondary outcome). The RC/ABD ratio was measured using respiratory inductive plethysmography during voluntary diaphragmatic breathing and natural breathing. Diaphragmatic mobility was measured by ultrasonography. A 6-minute walk test and health-related quality of life were also evaluated. Results: Immediately after the 4-week DBTP, the TG showed a greater abdominal motion during natural breathing quantified by a reduction in the RC/ABD ratio when compared with the CG (F=8.66; P<.001). Abdominal motion during voluntary diaphragmatic breathing after the intervention was also greater in the TG than in the CG (F=4.11; P<.05). The TG showed greater diaphragmatic mobility after the 4-week DBTP than did the CG (F=15.08; P<.001). An improvement in the 6-minute walk test and in health-related quality of life was also observed in the TG. Conclusions: DBTP for patients with chronic obstructive pulmonary disease induced increased diaphragm participation during natural breathing, resulting in an improvement in functional capacity.

Antidepressants prevent hierarchy destabilization induced by lipopolysaccharide administration in mice: a neurobiological approach to depression

In spite of the high prevalence and negative impact of depression, little is known about its pathophysiology. Basic research on depression needs new animal models in order to increase knowledge of the disease and search for new therapies. The work presented here aims to provide a neurobiologically validated model for investigating the relationships among sickness behavior, antidepressants treatment, and social dominance behavior. For this purpose, dominant individuals from dyads of male Swiss mice were treated with the bacterial endotoxin lipopolysaccharide (LPS) to induce social hierarchy destabilization. Two groups were treated with the antidepressants imipramine and fluoxetine prior to LPS administration. In these groups, antidepressant treatment prevented the occurrence of social destabilization. These results indicate that this model could be useful in providing new insights into the understanding of the brain systems involved in depression.

Coffee and Caffeine Protect against Liver Injury Induced by Thioacetamide in Male Wistar Rats

Coffee intake has been inversely related to the incidence of liver diseases, although there are controversies on whether these beneficial effects on human health are because of caffeine or other specific components in this popular beverage. Thus, this study evaluated the protective effects of coffee or caffeine intake on liver injury induced by repeated thioacetamide (TAA) administration in male Wistar rats. Rats were randomized into five groups: one untreated group (G1) and four groups (G2G5) treated with the hepatotoxicant TAA (200 similar to mg/kg b.w., i.p.) twice a week for 8 similar to weeks. Concomitantly, rats received tap water (G1 and G2), conventional coffee (G3), decaffeinated coffee (G4) or 0.1% caffeine (G5). After 8 similar to weeks of treatment, rats were killed and blood and liver samples were collected. Conventional and decaffeinated coffee and caffeine intake significantly reduced serum levels of alanine aminotransferase (ALT) (p similar to<similar to 0.001) and oxidized glutathione (p similar to<similar to 0.05), fibrosis/inflammation scores (p similar to<similar to 0.001), collagen volume fraction (p similar to<similar to 0.01) and transforming growth factor beta-1 (TGF-beta 1) protein expression (p similar to=similar to 0.001) in the liver from TAA-treated groups. In addition, conventional coffee and caffeine intake significantly reduced proliferating cellular nuclear antigen (PCNA) S-phase indexes (p similar to<similar to 0.001), but only conventional coffee reduced cleaved caspase-3 indexes (p similar to<similar to 0.001), active metalloproteinase 2 (p similar to=similar to 0.004) and the number of glutathione S-transferase placental form (GST-P)-positive preneoplastic lesions (p similar to<similar to 0.05) in the liver from TAA-treated groups. In conclusion, conventional coffee and 0.1% caffeine intake presented better beneficial effects than decaffeinated coffee against liver injury induced by TAA in male Wistar rats.

Deficient Regulatory T Cell Activity and Low Frequency of IL-17-Producing T Cells Correlate with the Extent of Cardiomyopathy in Human Chagas' Disease

Background: Myocardium damage during Chagas' disease results from the immunological imbalance between pro-and production of anti-inflammatory cytokines and has been explained based on the Th1-Th2 dichotomy and regulatory T cell activity. Recently, we demonstrated that IL-17 produced during experimental T. cruzi infection regulates Th1 cells differentiation and parasite induced myocarditis. Here, we investigated the role of IL-17 and regulatory T cell during human Chagas' disease. Methodology/Principal Findings: First, we observed CD4(+)IL-17(+) T cells in culture of peripheral blood mononuclear cells (PBMC) from Chagas' disease patients and we evaluated Th1, Th2, Th17 cytokine profile production in the PBMC cells from Chagas' disease patients (cardiomyopathy-free, and with mild, moderate or severe cardiomyopathy) cultured with T. cruzi antigen. Cultures of PBMC from patients with moderate and severe cardiomyopathy produced high levels of TNF-alpha, IFN-gamma and low levels of IL-10, when compared to mild cardiomyopathy or cardiomyopathy-free patients. Flow cytometry analysis showed higher CD4(+)IL-17(+) cells in PBMC cultured from patients without or with mild cardiomyopathy, in comparison to patients with moderate or severe cardiomyopathy. We then analyzed the presence and function of regulatory T cells in all patients. All groups of Chagas' disease patients presented the same frequency of CD4(+)CD25(+) regulatory T cells. However, CD4(+)CD25(+) T cells from patients with mild cardiomyopathy or cardiomyopathy-free showed higher suppressive activity than those with moderate and severe cardiomyopathy. IFN-gamma levels during chronic Chagas' disease are inversely correlated to the LVEF (P = 0.007, r = -0.614), while regulatory T cell activity is directly correlated with LVEF (P = 0.022, r = 0.500). Conclusion/Significance: These results indicate that reduced production of the cytokines IL-10 and IL-17 in association with high levels of IFN-gamma and TNF-alpha is correlated with the severity of the Chagas' disease cardiomyopathy, and the immunological imbalance observed may be causally related with deficient suppressor activity of regulatory T cells that controls myocardial inflammation.