Glioma Pericytes Promote Angiogenesis by Producing Periostin.

Glioma is the prevalent aggressive primary brain tumor, with a very poor prognosis. The absence of advanced understanding of the roles played by the cells within the glioma microenvironment limits the development of effective drugs. A recent study indicates that periostin expressed by pericytes is crucial for glioma angiogenesis. Here, we describe succinctly the results and implications of this discovery in what we know about pericytes within the glioma microenvironment. The emerging knowledge from this work will benefit the development of therapies for gliomas.

Mechanism of metformin action in MCF-7 and MDA-MB-231 human breast cancer cells involves oxidative stress generation, DNA damage, and transforming growth factor ß1 induction.

The participation of oxidative stress in the mechanism of metformin action in breast cancer remains unclear. We investigated the effects of clinical (6 and 30 µM) and experimental concentrations of metformin (1000 and 5000 µM) in MCF-7 and in MDA-MB-231 cells, verifying cytotoxicity, oxidative stress, DNA damage, and intracellular pathways related to cell growth and survival after 24 h of drug exposure. Clinical concentrations of metformin decreased metabolic activity of MCF-7 cells in the MTT assay, which showed increased oxidative stress and DNA damage, although cell death and impairment in the proliferative capacity were observed only at higher concentrations. The reduction in metabolic activity and proliferation in MDA-MB-231 cells was present only at experimental concentrations after 24 h of drug exposition. Oxidative stress and DNA damage were induced in this cell line at experimental concentrations. The drug decreased cytoplasmic extracellular signal-regulated kinases 1 and 2 (ERK1/2) and AKT and increased nuclear p53 and cytoplasmic transforming growth factor ß1 (TGF-ß1) in both cell lines. These findings suggest that metformin reduces cell survival by increasing reactive oxygen species, which induce DNA damage and apoptosis. A relationship between the increase in TGF-ß1 and p53 levels and the decrease in ERK1/2 and AKT was also observed. These findings suggest the mechanism of action of metformin in both breast cancer cell lineages, whereas cell line specific undergoes redox changes in the cells in which proliferation and survival signaling are modified. Taken together, these results highlight the potential clinical utility of metformin as an adjuvant during the treatment of luminal and triple-negative breast cancer.

Reactive oxygen species play a role in muscle wasting during thyrotoxicosis.

The role of reactive oxygen species (ROS) in muscle protein hydrolysis and protein oxidation in thyrotoxicosis has not been explored. This study indicates that ROS play a role in skeletal muscle wasting pathways in thyrotoxicosis. Two experimental groups (rats) were treated for 5 days with either 3,3',5-triiodothyronine (HT) or HT with α-tocopherol (HT + αT). Two controls were used, vehicle (Control) and control treated with αT (Control + αT). Serum T3, peritoneal fat, serum glycerol, muscle and body weight, temperature, mitochondrial metabolism (cytochrome c oxidase activity), oxidative stress parameters and proteolytic activities were examined. High body temperature induced by HT returned to normal when animals were treated with αT, although total body and muscle weight did not. An increase in lipolysis was observed in the HT + αT group, as peritoneal fat decreased significantly together with an increase in serum glycerol. GSH, GSSG and total radical-trapping antioxidant parameter (TRAP) decreased and catalase activity increased in the HT group. The glutathione redox ratio was higher in HT + αT than in both HT and Control + αT groups. Carbonyl proteins, AOPP, mitochondrial and chymotrypsin-like proteolytic activities were higher in the HT group than in the Control. HT treatment with αT restored mitochondrial metabolism, TRAP, carbonyl protein, chymotrypsin-like activity and AOPP to the level as that of the Control + αT. Calpain activity was lower in the HT + αT group than in HT and Control + αT and superoxide dismutase (SOD) activity was higher in the HT + αT group than in the Control + αT. Although αT did not reverse muscle loss, ROS was involved in proteolysis to some degree.

Oxidative status and chymotrypsin-like activity in right and left ventricle hypertrophy in an experimental model of emphysema.

Although cardiac muscle hypertrophy has been studied in association with several diseases, its mechanism in patients with emphysema, in particular in relation to oxidative stress and proteolysis, remains unknown. The role of oxidative stress and proteolysis in right and left ventricle hypertrophy was investigated in hamsters with emphysema induced by 2 different doses of papain (20mg/mL, E20 and 40mg/mL, E40). The thickness of the ventricles, total and cardiac weight, lipid peroxidation, carbonyl proteins, total antioxidant capacity (TAC), and proteasomal proteolytic activity were evaluated in the right ventricle (RV) and the left ventricle (LV) of control and emphysema hamsters. RV thickness was increased by 12% in the E20 group and by 29% in the E40 group. Lipid peroxidation measured by chemiluminescence was increased in the E40 group (from 3350.68±392.44URL/g tissue to 4696.63±1076.70URL/g tissue, p<0.05). TAC also increased only in the E40 group. In the LV, chemiluminescence values increased from 4044.77±503.39 to 5517.10±388.27 in the E20 group and to 8169.14±1748.77URL/g tissue in the E40 group (p<0.05, both). TAC significantly increased in the E20 and E40 groups. No differences were detected in substances reactive to thiobarbituric acid or carbonyl proteins when comparing ventricles or doses. Chymotrypsin-like proteolytic activity significantly decreased in both groups and ventricles. Emphysema can induce right and left ventricle lipid peroxidation and result in antioxidant mobilization. These data together support the idea that cardiac hypertrophy in response to emphysema is mediated in part by proteolytic pathways with involvement of reactive species.

Lung injury-dependent oxidative status and chymotrypsin-like activity of skeletal muscles in hamsters with experimental emphysema.

BACKGROUND: Peripheral skeletal muscle is altered in patients suffering from emphysema and chronic obstructive pulmonary disease (COPD). Oxidative stress have been demonstrated to participate on skeletal muscle loss of several states, including disuse atrophy, mechanical ventilation, and chronic diseases. No evidences have demonstrated the occurance in a severity manner. METHODS: We evaluated body weight, muscle loss, oxidative stress, and chymotrypsin-like proteolytic activity in the gastrocnemius muscle of emphysemic hamsters. The experimental animals had 2 different severities of lung damage from experimental emphysema induced by 20 mg/mL (E20) and 40 mg/mL (E40) papain. RESULTS: The severity of emphysema increased significantly in E20 (60.52 ± 2.8, p < 0.05) and E40 (52.27 ± 4.7; crossed the alveolar intercepts) groups. As compared to the control group, there was a reduction on body (171.6 ± 15.9 g) and muscle weight (251.87 ± 24.87 mg) in the E20 group (157.5 ± 10.3 mg and 230.12 ± 23.52 mg, for body and muscle weight, respectively), which was accentuated in the E40 group (137.4 ± 7.2 g and 197.87 ± 10.49 mg, for body and muscle weight, respectively). Additionally, the thiobarbituric acid reactive substances (TBARS), tert-butyl hydroperoxide-initiated chemiluminescence (CL), carbonylated proteins, and chymotrypsin-like proteolytic activity were elevated in the E40 group as compared to the E20 group (p < 0.05 for all comparisons). The severity of emphysema significantly correlated with the progressive increase in CL (r = -0.95), TBARS (r = -0.98), carbonyl proteins (r = -0.99), and chymotrypsin-like proteolytic activity (r = -0.90). Furthermore, augmentation of proteolytic activity correlated significantly with CL (r = 0.97), TBARS (r = 0.96), and carbonyl proteins (r = 0.91). CONCLUSIONS: Taken together, the results of the present study suggest that muscle atrophy observed in this model of emphysema is mediated by increased muscle chymotrypsin-like activity, with possible involvement of oxidative stress in a severity-dependent manner.

Computational Biology Helps Understand How Polyploid Giant Cancer Cells Drive Tumor Success.

Precision and organization govern the cell cycle, ensuring normal proliferation. However, some cells may undergo abnormal cell divisions (neosis) or variations of mitotic cycles (endopolyploidy). Consequently, the formation of polyploid giant cancer cells (PGCCs), critical for tumor survival, resistance, and immortalization, can occur. Newly formed cells end up accessing numerous multicellular and unicellular programs that enable metastasis, drug resistance, tumor recurrence, and self-renewal or diverse clone formation. An integrative literature review was carried out, searching articles in several sites, including: PUBMED, NCBI-PMC, and Google Academic, published in English, indexed in referenced databases and without a publication time filter, but prioritizing articles from the last 3 years, to answer the following questions: (i) "What is the current knowledge about polyploidy in tumors?"; (ii) "What are the applications of computational studies for the understanding of cancer polyploidy?"; and (iii) "How do PGCCs contribute to tumorigenesis?"

Extracellular vesicle-mediated crosstalk between melanoma and the immune system: Impact on tumor progression and therapy response.

Melanoma is a very lethal tumor type that easily spreads and colonizes regional and distant tissues. Crucial phenotypic changes that favor melanoma metastasis are interposed by the tumor microenvironment (TME), representing a complex network in which malignant cells communicate not only with each other but also with stromal and immune cells. This cell-cell communication can be mediated by extracellular vesicles (EVs), which are lipid bilayer-delimited particles capable of carrying a wide variety of bioactive compounds. Both melanoma-derived or TME-derived EVs deliver important pro- and antitumor signals implicated in various stages of tumor progression, such as proliferation, metastasis, and treatment response. In this review, we highlight the recent advances in EV-mediated crosstalk between melanoma and immune cells and other important cells of the TME, and address different aspects of this bidirectional interaction as well as how this may hinder or trigger the development and progression of melanoma. We also discuss the potential of using EVs as biomarkers and therapeutic strategies for melanoma.

Gestational outcomes in women infected by Zika virus during pregnancy in Mato Grosso do Sul, Brazil: A cross-sectional study.

OBJECTIVES: This study aimed to describe the demographic and clinical parameters of women infected by Zika virus who had infants with stigmata of Congenital Zika Syndrome (CZS) versus those who had normal-appearing infants at birth, thereby providing further details on the clinical caveats of neonatal ZIKV infection. METHODOLOGY: This cross-sectional study was performed in the state of Mato Grosso do Sul, Central-West region of Brazil, and included 117 mother-infant pairs who were interviewed and 120 gestational outcomes. All mothers had laboratory confirmation by qRT-PCR of ZIKV infection during pregnancy. RESULTS: The prevalence of congenital abnormalities related to ZIKV was 2.69 cases per 10,000 live births during this period. Exanthem was the main clinical finding, observed in 92.5% of the mothers in this study. Regarding the timing of ZIKV infection, the first trimester was the most frequent time of infection among mothers of infants with CZS (54.55%) (p=0.0007). The case fatality rate was 5% (n=6). Among the 23 children who were classified as having CZS, 13 (56.52%) of them presented with microcephaly. Only 13 (56.52%) children with CZS were tested by qRT-PCR for ZIKV infection at birth, five (38%) were positive. CONCLUSIONS: This study highlights the congenital alterations of ZIKV infection during pregnancy in an epidemic burst, demonstrating that the alterations found in other studies are similar to the present research.

Looking beyond the skin: Cutaneous and systemic oxidative stress in UVB-induced squamous cell carcinoma in hairless mice.

Cumulative ultraviolet (UV) exposure is associated with squamous skin cell carcinoma. UV radiation induces oxidative modifications in biomolecules of the skin leading to photocarcinogenesis. Indeed, the cyclobutene pyrimidine dimers and other dimers formed by photoaddition between carbon-carbon bonds also have an important role in the initiation process. However, information on the systemic redox status during these processes is scarce. Thus, we investigated the systemic redox profile in UVB-induced squamous cell carcinoma in mice. Female hairless mice were exposed to UVB radiation (cumulative dose = 17.1 J/cm2). The dorsal skin of these mice developed actinic keratosis (AK) and squamous cell carcinoma (SCC) and presented increased levels of oxidative and nitrosative stress biomarkers (4-hydroxy-2-nonenal and 3-nitrotyrosine), and decreased antioxidant defenses. Systemically, we observed the consumption of plasmatic antioxidant defenses and increased levels of advanced oxidized protein products (AOPP), an oxidative stress product derived from systemic inflammatory response. Taken together, our results indicate that UVB chronic irradiation leads not only to adjacent and tumoral oxidative stress in the skin, but it systemically is reflected through the blood. These new findings clarify some aspects of the pathogenesis of SCC and should assist in formulating better chemoprevention strategies, while avoiding additional primary SCC development and metastasis.

In vitro antioxidant potential and in vivo effects of Schinus terebinthifolia Raddi leaf extract in diabetic rats and determination of chemical composition by HPLC-ESI-MS/MS.

The present study investigated the in vitro and in vivo antioxidant potential and phytochemical composition of Schinus terebinthifolia, which is widely used in folk medicine for various therapeutic purposes. The in vitro analyses indicated that the hydroethanolic extract (HE) had 312.50 ± 0.50 mg GAE/g of total phenols. It also presented anti-DPPH• and anti-ABTS•+ activity, reduced phosphomolybden and metal ions and blocked the bleaching of ß-carotene. The HE at concentrations of 3.0 and 2.0 µg/mL had TRAP values of 2.223 ± 0.018 and 1.894 ± 0.026 µM Trolox, respectively. The HE increased the availability of antioxidants in plasma in treated animals in vivo. HPLC-ESI-MS/MS indicated the presence of 11 phenols: cumaric acid, (+)-catechin, myricetin-3-O-glicuronide, kaempferol-3-O-glucoside, myricetin, myricitrin, quercetin, gallic acid, methyl galate, pentagalloyl glucose and ethyl galate. Thus, S. terebinthifolia has potential for the prevention or treatment of diseases that are related to oxidative stress, such as diabetes mellitus.

Increased nitric oxide levels in cerebellum of cachectic rats with Walker 256 solid tumor.

In cancer cachexia, the role of nitric oxide (NO) in the central nervous system remains unclear. Cerebellar degeneration has been reported in cancer patients, but the participation of NO has not been studied. Thus, this study investigated the mechanism of oxidative cerebellar injury in a time-course cancer cachexia experimental model. The cachexia index is progressive and evident during the evolution of the tumor. Nitric oxide and lipid hydroperoxidation quantification was performed using a very sensitive and precise chemiluminescence method, which showed that both analyzed parameters were increased after tumor implantation. In the day 5 group, NO was significantly increased, and this experimental time was chosen to treat the rats with the NO inhibitors N-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine (AG). When treated with NO inhibitors, a significant decrease in both NO and lipid hydroperoxide levels occurred in the cerebellum. 3-nitrotyrosine was also analyzed in cerebellar tissue by immunohistochemistry; it was increased at the three experimental time points studied, and decreased when treated with L-NAME and AG. Besides demonstrating that lipid hydroperoxidation in the cerebellum of rats with cachexia increases in a time-dependent manner, this study is the first to describe the participation of NO and its oxidized product 3-NT in the cerebellum of cachectic rats bearing the Walker 256 solid tumor.

Nimesulide-induced fatal acute liver failure in an elderly woman with metastatic biliary adenocarcinoma. A case report.

CONTEXT: Nimesulide is a selective inhibitor of the enzyme cyclooxygenase 2. Although considered to be a safe drug, cases of acute hepatitis and fulminant liver failure have been reported in Europe, the United States and South America, especially among elderly female patients. Until now, there had not been any reports in the literature relating to Brazilian subjects. CASE REPORT: An 81-year old female who had been using nimesulide therapy for six days presented hematemesis and epistaxis two days before hospitalization. Clinical examination showed an extensive coagulation disorder, diffuse hematomas, hypotension and tachypnea. Laboratory tests revealed abnormalities in coagulation tests; leukocytosis; reduced platelet, hemoglobin and red blood cell counts; and elevated direct bilirubin, serum aspartate transaminase (AST), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase and renal function biomarkers. Hepatitis B and C tests were not reactive. Carcinoembryonic antigen (CEA), CA-19-9 and CA-125 levels were increased by, respectively, 1,000, 10,000 and 13 fold, whereas the alpha-fetoprotein level was normal, thus indicating a malignant tumor in the bile duct that did not originate from the liver. Thirty-six hours after hospitalization, the patient's condition worsened, leading to death. The necropsy findings included acute hepatitis with hepatocellular collapse, as well as metastasis of a carcinoma, probably from the bile duct. CONCLUSION: Despite the carcinoma presented by the patient, nimesulide use may have contributed towards the fatal acute liver failure. Until this issue has been clarified, caution is required in prescribing nimesulide for liver disease patients.

Systemic oxidative profile after tumor removal and the tumor microenvironment in melanoma patients.

This study highlights the systemic oxidative changes in patients submitted to primary cutaneous melanoma removal. Cutaneous melanoma is highly aggressive and its incidence is increasing worldwide. We evaluated systemic oxidative stress (OS) and 3-nitrotyrosine (3-NT) expression in melanoma tissue in relation to the Breslow thickness in patients under surveillance. Forty-three patients with cutaneous melanoma and 50 healthy volunteers were recruited. Patients were divided into two groups according to the tumor's Breslow thickness: T1/T2 (<2 mm) and T3/T4 (≥2 mm). Systemic OS and inflammatory mediators were evaluated in plasma, and the 3-NT expression was analyzed via immunohistochemistry. Compared with the controls, the patients had lower blood levels of reduced glutathione, higher malondialdehyde and thiol levels, and a higher total radical-trapping antioxidant parameter to uric acid ratio. The C-reactive protein and γ-glutamyl transpeptidase were increased only in the T3/T4 group. High levels of 3-NT were present only in T3/T4 patients. Our data suggested that a correlation exists between the Breslow thickness and a systemic pro-oxidant status, and that oxidative changes induced by the melanoma remain in the microenvironment post-surgery, demonstrating a role for oxygen species in melanoma.

[Profile of suicide attempts using intentional overdose with medicines, treated by a poison control center in Paraná State, Brazil]. / Perfil das tentativas de suicídio por sobredose intencional de medicamentos atendidas por um Centro de Controle de Intoxicações do Paraná, Brasil.

This study presents the profile of suicide attempts using intentional overdose with medicines, treated at the Poison Control Center in Londrina, Paraná State, Brazil. A retrospective study of cases treated from 1997 to 2007 was performed. Suicide attempts were significant among unemployed men, housewives, and retired women, and there was an association with other substances in 51.5% of the cases, with a higher frequency among men. 51.1% of the men combined the medicine with an alcoholic beverage, while in women, 84.8% of the associations involved other medicines. The most frequent pharmacological groups were tranquilizers (25.5%), antidepressants (17%), anticonvulsants (15%), and NSAIDs (11.9%). Prescribers must evaluate patients correctly before prescribing psychoactive drugs, since this is the pharmacological group most frequently associated with suicide attempts. Awareness-raising campaigns for rational use of medicines and social programs for suicidal patients should also help decrease the frequency of such cases.

Nimesulide-induced fatal acute liver failure in an elderly woman with metastatic biliary adenocarcinoma. A case report / Insuficiência hepática aguda fatal induzida por nimesulida em uma mulher idosa com adenocarcinoma biliar metastático. Um relato de caso

CONTEXT:Nimesulide is a selective inhibitor of the enzyme cyclooxygenase 2. Although considered to be a safe drug, cases of acute hepatitis and fulminant liver failure have been reported in Europe, the United States and South America, especially among elderly female patients. Until now, there had not been any reports in the literature relating to Brazilian subjects.CASE REPORT:An 81-year old female who had been using nimesulide therapy for six days presented hematemesis and epistaxis two days before hospitalization. Clinical examination showed an extensive coagulation disorder, diffuse hematomas, hypotension and tachypnea. Laboratory tests revealed abnormalities in coagulation tests; leukocytosis; reduced platelet, hemoglobin and red blood cell counts; and elevated direct bilirubin, serum aspartate transaminase (AST), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase and renal function biomarkers. Hepatitis B and C tests were not reactive. Carcinoembryonic antigen (CEA), CA-19-9 and CA-125 levels were increased by, respectively, 1,000, 10,000 and 13 fold, whereas the alpha-fetoprotein level was normal, thus indicating a malignant tumor in the bile duct that did not originate from the liver. Thirty-six hours after hospitalization, the patient's condition worsened, leading to death. The necropsy findings included acute hepatitis with hepatocellular collapse, as well as metastasis of a carcinoma, probably from the bile duct.CONCLUSION:Despite the carcinoma presented by the patient, nimesulide use may have contributed towards the fatal acute liver failure. Until this issue has been clarified, caution is required in prescribing nimesulide for liver disease patients.

CONTEXTO:A nimesulida é um inibidor seletivo da enzima ciclo-oxigenase 2. Apesar de ela ser considerada fármaco seguro, casos de hepatite aguda e falência hepática fulminante foram descritos na Europa, Estados Unidos e América do Sul, principalmente em idosos do sexo feminino. Até o momento não há relatos na literatura em indivíduos brasileiros.RELATO DE CASO:Mulher de 81 anos, em uso terapêutico de nimesulida por seis dias, apresentou hematêmese e epistaxe dois dias antes da hospitalização. O exame clínico mostrou importante distúrbio de coagulação, hematomas difusos, hipotensão e taquipneia. Os exames laboratoriais mostravam alteração das provas de coagulação, leucocitose, redução do número de plaquetas, hemoglobina e hemácias, aumento de bilirrubina direta, elevação dos valores de aspartato aminotransferase (AST), gama glutamil transpeptidase (GGT), fosfatase alcalina e marcadores de função renal. Exames para hepatite B e C apresentaram-se não reagentes. Elevados níveis dos marcadores antígeno carcinoembriônico (CEA), CA-19-9 e CA-125 foram encontrados (1.000, 10.000 e 13 vezes, respectivamente), enquanto a alfa-fetoproteína estava normal, indicando um tumor maligno no ducto biliar, não oriundo do fígado. Trinta e seis horas após a hospitalização, a paciente evoluiu a óbito. Os achados necroscópicos incluíram hepatite aguda com colapso hepatocelular, bem como metástase de carcinoma, provavelmente do ducto biliar.CONCLUSÃO:Apesar do carcinoma apresentado pela paciente, o uso de nimesulida pode ter contribuído para o dano hepático. Até que esta questão seja esclarecida, a prescrição de nimesulida deve ser cuidadosa para pacientes com doenças hepáticas.

Perfil das tentativas de suicidio por sobredose intencional de medicamentos atendidas por um centro de controle de intoxicacoes do Parana, Brasil / Profile of suicide attempts using intentional overdose with medicines, treated by a poison control center in Parana State, Brazil

Este trabalho apresenta o perfil das tentativas de suicidio atendidas pelo Centro de Controle de Intoxicacoes da cidade de Londrina, Parana, Brasil. Foi realizado um estudo retrospectivo dos casos atendidos entre 1997-2007. As tentativas de suicidio foram significativas entre homens desempregados e mulheres donas-de-casa/aposentadas, e houve associacao com outras substancias em 51,5 por cento dos casos, sendo a frequencia maior entre os homens. 51,1 por cento dos homens associaram o medicamento com bebida alcoolica, e entre as mulheres, 84,8 por cento das associacoes se referiram a medicamentos. Os grupos farmacologicos de maior frequencia foram os tranquilizantes (25,5 por cento), antidepressivos (17 por cento), anticonvulsivos (15 por cento) e AINES (11,9 por cento), respectivamente. Os prescritores devem avaliar corretamente o paciente antes de receitar psicofarmacos, uma vez que esse e o grupo farmacologico mais frequente nas tentativas de suicidio. Campanhas de conscientizacao para o uso racional de medicamentos, juntamente com programas sociais de atendimento ao paciente suicida, tambem poderiam contribuir na diminuicao da frequencia desses casos.

This study presents the profile of suicide attempts using intentional overdose with medicines, treated at the Poison Control Center in Londrina, Parana State, Brazil. A retrospective study of cases treated from 1997 to 2007 was performed. Suicide attempts were significant among unemployed men, housewives, and retired women, and there was an association with other substances in 51.5 percent of the cases, with a higher frequency among men. 51.1 percent of the men combined the medicine with an alcoholic beverage, while in women, 84.8 percent of the associations involved other medicines. The most frequent pharmacological groups were tranquilizers (25.5 percent), antidepressants (17 percent), anticonvulsants (15 percent), and NSAIDs (11.9 percent). Prescribers must evaluate patients correctly before prescribing psychoactive drugs, since this is the pharmacological group most frequently associated with suicide attempts. Awareness-raising campaigns for rational use of medicines and social programs for suicidal patients should also help decrease the frequency of such cases.

Participação de células T regulatórias (Tregs) na imunopatogênese da infecção pelo vírus da imunodeficiência humana 1 (HIV-1) / Regulatory T cells participation in the infection immunopathogenesis by the Human Immunodeficiency Vírus

A sobrevivência de pacientes infectados pelo vírus da imunodeficiência humana (HIV-1) é relacionada à prevenção e ao tratamento eficaz de infecções oportunistas. É conhecido que os principais parâmetros para avaliar a progressão da doença causada pelo HIV-1 são contagem de células T CD4+ e carga viral do HIV-1. Células T regulatórias têm sido foco de intensas investigações dentro do sistema imunológico como também na patogênese de diversas doenças. Sabe-se que as células T reguladoras (Tregs) CD4+CD25+FoxP3+ atuam na modulação da ativação imune, funcionando como mediadores críticos da homeostasia imune e da auto-tolerância. Além disso, recentes estudos têm demonstrado que as células Tregs não se limitam à prevenção de auto-imunidade, mas são importantes no controle todas as formas de respostas imunes no contexto de inflamação, infecção, alergia, transplantes e imunidade tumoral. Muitos autores têm identificado as Tregs como células efetoras benéficas no contexto da AIDS, porém há discordância. Tregs podem sustentar importante função na imunopatologia da infecção pelo HIV devido a atividade supressora sobre ativação celular e função efetora. Neste contexto, esta revisão aborda os aspectos moleculares e imunológicos das Tregs no sistema HIV.

The survival of patients infected with human immunodeficiency virus (HIV-1) is related to the prevention and effective treatment of opportunistic infections. It is known that the main parameters to evaluate the progression of disease caused by HIV-1 is the counting of CD4 + T cells and viral load of HIV-1. Regulatory T cells has been considered the focus of intense research within the immune system as well as in the pathogenesis of several diseases. Natural regulatory T cells (Tregs) CD4+CD25+ act in the modulation of immune activation, functioning as critical mediators of immune homeostasis and self-tolerance. Furthermore, recent studies has shown that the function of Tregs cells is not limited to the prevention of autoimmunity, but is also important to control all forms of immune responses in the context of inflammation, infection, allergy, transplantation and tumor immunity. Many authors have identified Tregs as beneficial effector cells in the context of AIDS, but other researchers disagree. Tregs can exert an important role in the immunopathology of HIV infection due to the suppressor activity on cellular activation and effector function. Thus, this review discusses the molecular and immunological aspects of Tregs in the HIV system.