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ArtigoDireito Autoral
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- INI - Artigos de Periódicos [3498]
- IOC - Artigos de Periódicos [12791]
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EFFICACY OF DIFFERENT NITRIC OXIDE-BASED STRATEGIES IN PREVENTING EXPERIMENTAL CEREBRAL MALARIA BY PLASMODIUM BERGHEI ANKA
Afiliação
La Jolla Bioengineering Institute. Center for Malaria Research. San Diego, CA, USA / Universidade Federal do Rio de Janeiro. Laboratório de Inflamação e Imunidade. Rio de Janeiro, RJ, Brasil.
La Jolla Bioengineering Institute. Center for Malaria Research. San Diego, CA, USA / Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Serviço de Parasitologia. Rio de Janeiro, RJ, Brasil.
La Jolla Bioengineering Institute. Center for Malaria Research. San Diego, CA, USA.
La Jolla Bioengineering Institute. Center for Malaria Research. San Diego, CA, USA / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil.
La Jolla Bioengineering Institute. Center for Malaria Research. San Diego, CA, USA / Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Serviço de Parasitologia. Rio de Janeiro, RJ, Brasil.
La Jolla Bioengineering Institute. Center for Malaria Research. San Diego, CA, USA.
La Jolla Bioengineering Institute. Center for Malaria Research. San Diego, CA, USA / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil.
Resumo em Inglês
Background: Low nitric oxide (NO) bioavailability plays a role in the pathogenesis of human as well as of experimental cerebral malaria (ECM) caused by Plasmodium berghei ANKA (PbA). ECM is partially prevented by administration of the NOdonor dipropylenetriamine NONOate (DPTA-NO) at high concentration (1 mg/mouse), which also induces major side effects
such as a sharp drop in blood pressure. We asked whether alternative strategies to improve NO bioavailability with minor side effects would also be effective in preventing ECM. Methodology/Principal Findings: Mice were infected with PbA and prophylactically treated twice a day with bolus injections of L-arginine, Nv-hydroxy-nor-Arginine (nor-NOHA), tetrahydrobiopterin (BH4), separately or combined, sodium nitrite, sildenafil or sildenafil plus DPTA-NO starting on day 0 of infection. L-arginine and BH4 supplementation, with or without arginase inhibition by nor-NOHA, increased plasma nitrite levels but failed to protect against ECM development. Accordingly, prophylactic treatment with continuous delivery of L-arginine using osmotic pumps also did not improve survival. Similar outcomes were observed with sodium nitrite sildenafil (aimed at inhibiting hosphodiesterase-5) or with DPTA-NO. However, sildenafil (0.1 mg/mouse) in combination with a lower dose (0.1 mg/mouse) of DPTA-NO decreased ECM incidence (8267.4% mortality in the saline group and 38610.6% in the treated group; p,0.05). The combined prophylactic therapy did not aggravate anemia, had delayed effects in systolic, diastolic and mean arterial blood pressure and induced lower effects in pulse pressure when compared to DPTA-NO 1 mg/mouse. Conclusions/Significance: These data show that sildenafil lowers the amount of NO-donor needed to prevent ECM, resulting also in lesser side effects. Prophylactic L-arginine when given in bolus or continuous delivery and bolus BH4 supplementation, with or without arginase inhibition, were able to increase NO bioavailability in PbA-infected mice but failed to decrease ECM incidence in the doses and protocol used.
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