Malaria is an infectious disease and a serious public health problem in the world, with 3.3 billion people in endemic areas in 100 countries and about 200 million new cases each year, resulting in almost 1 million deaths in 2018. Although studies look for strategies to eradicate malaria, it is necessary to know more about its pathophysiology to understand the underlying mechanisms involved, particularly the redox balance, to guarantee success in combating this disease. In this review, we addressed the involvement of oxidative stress in malaria and the potential benefits of antioxidant supplementation as an adjuvant antimalarial therapy.
BackgroundMalaria infection can cause high oxidative stress, which could lead to the development of severe forms of malaria, such as pulmonary malaria. In recent years, the role of reactive oxygen species in the pathogenesis of the disease has been discussed, as well as the potential benefit of antioxidants supplementation. The aim of this study was to investigate the effects of N-acetyl cysteine (NAC) or mushroom Agaricus sylvaticus supplementation on the pulmonary oxidative changes in an experimental model of malaria caused by Plasmodium berghei strain ANKA.MethodsSwiss male mice were infected with P. berghei and treated with NAC or AS. Samples of lung tissue and whole blood were collected after one, three, five, seven or ten days of infection for the assessment of thiobarbituric acid reactive substances (TBARS), trolox equivalent antioxidant capacity (TEAC), nitrites and nitrates (NN) and to assess the degree of parasitaemia.ResultsAlthough parasitaemia increased progressively with the evolution of the disease in all infected groups, there was a significant decrease from the seventh to the tenth day of infection in both antioxidant-supplemented groups. Results showed significant higher levels of TEAC in both supplemented groups, the highest occurring in the group supplemented with A. sylvaticus. In parallel, TBARS showed similar levels among all groups, while levels of NN were higher in animals supplemented with NAC in relation to the positive control groups and A. sylvaticus, whose levels were similar to the negative control group.ConclusionOxidative stress arising from plasmodial infection was attenuated by supplementation of both antioxidants, but A. sylvaticus proved to be more effective and has the potential to become an important tool in the adjuvant therapy of malaria.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0717-0) contains supplementary material, which is available to authorized users.
Nitric oxide (NO) is an important mediator molecule in inflammatory processes, but its role in the pathophysiology of malaria is still uncertain. To investigate the NO synthesis inhibition on the oxidative changes induced by Plasmodium berghei infection in mice, malaria was induced in 150 animals, of which 75 animals were treated with the NO inhibitor L-NAME; the remaining animals were sham controls. All animals underwent euthanasia 1, 5, 10, 15, or 20 days after infection for the collection of lungs, brain, and blood. Parasitemia was determined, and the survival of the animals was evaluated. Tissue samples were assayed for nitrites and nitrates (NN), thiobarbituric acid reactive substances (TBARS), and total Trolox equivalent antioxidant capacity (TEAC). A histopathological study was performed. Mortality rates in the L-NAME group were always higher than those in the controls. In the brain, NN was lower in the L-NAME group. Parasitemia and its progression rate were greater in the control group. By the 5th day of infection, mice treated with L-NAME showed cerebral edema and interstitial pneumonia of greater intensity than controls. In conclusion, the anti-inflammatory and hemodynamic effects of NO surpass its pro-oxidant role in murine malaria.
Malaria is a disease that affects thousands of people around the world every year. Its pathogenesis is associated with the production of reactive oxygen and nitrogen species (RONS) and lower levels of micronutrients and antioxidants. Patients under drug treatment have high levels of oxidative stress biomarkers in the body tissues, which limits the use of these drugs. Therefore, several studies have suggested that RONS inhibition may represent an adjuvant therapeutic strategy in the treatment of these patients by increasing the antioxidant capacity of the host. In this sense, supplementation with antioxidant compounds such as zinc, selenium, and vitamins A, C, and E has been suggested as part of the treatment. Among dietary antioxidants, lycopene is the most powerful antioxidant among the main carotenoids. This review aimed to describe the main mechanisms inducing oxidative stress during malaria, highlighting the production of RONS as a defense mechanism against the infection induced by the ischemia-reperfusion syndrome, the metabolism of the parasite, and the metabolism of antimalarial drugs. Furthermore, the effects of lycopene on several diseases in which oxidative stress is implicated as a cause are outlined, providing information about its mechanism of action, and providing an evidence-based justification for its supplementation in malaria.
Os incômodos sonoros têm crescido nas últimas décadas, principalmente nas maiores aglomerações urbanas. Em 2004, Belém foi apontada, em pesquisa realizada pelo IBGE como a capital mais ruidosa do Brasil. Assim com o objetivo de verificar o panorama da poluição sonora no âmbito da Região Metropolitana de Belém-Pará, no período de 01 de janeiro a 31 de dezembro de 2006, realizou-se pesquisa nos arquivos da Gerência de Perícias Tecnológicas, do Centro de Perícias Científicas "Renato Chaves", onde foram selecionadas. Foram apuradas 80 solicitações de perícias no período estudado, as fontes de poluição sonora contempladas na categoria entretenimento foram as de maior freqüência de solicitação de perícia que juntamente com a categoria oficina, ocupam o primeiro lugar, ambas com 22% das solicitações feitas durante o período estudado.
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