Cerebral malaria (CM) is a major complication of infection by Plasmodium falciparum. It affects mainly children under 5 years old in sub-Saharan Africa and shows a high mortality rate even when anti- malarial treatment is administered. Adjunctive therapies for CM capable of improving survival and decreasing incidence of sequelae are urgently needed. In the murine model of CM by Plasmodium berghei ANKA (PbA), CM has been associated to low nitric oxide (NO) bioavailability, and treatment with exogenous NO prevented CM development. On the other hand, plasma free heme has been incriminated in the genesis of CM. We propose that restoring NO and/or counteracting heme toxicity are potentially powerful approaches for adjunctive therapy of CM. The overall goal of this proposal is to define one or more treatment strategies based on NO restoration and/or free heme detoxification that show high efficacy as adjunctive therapy for cerebral malaria, using arthemeter as anti-malarial drug. Such a therapeutic procedure shall significantly improve survival in relation to arthemeter alone, ideally inducing negligible side effects and toxicity, and present good potential to be translated into clinical use. The PbA model of CM will be used. First, infected mice will be treated with three different dosages of each of the following NO donor compounds: DPTA-NO, NO-containing nanoparticles, S-nitroso- pegylated-albumin, GSNO, nitrite and nitroglycerin, as well as with the 5-phosphodiesterase inhibitor sildenafil. Compounds aimed at blocking the deleterious effect of heme (recombinant haptoglobin, hemopexin, protoporphyrin IX and mesoporphyrin IX), inducing hemeoxygenase-1 (HO-1: hyperbaric oxygen, curcumin, furan-2-yl-3-pyridin-2-yl-propenone, -deoxy-delta 12,14-prostaglandin J2) or providing anti-oxidant protection against heme-induced oxidative stress (N-Acethil cystein, desferoxamine) will be tested as well. The compounds able to prevent CM development in mice will be tested in a scheme of combined therapy with arthemeter with the purpose of rescuing mice with established CM at early or late stages. For each treatment, liver, kidney and respiratory physiology will be assessed to determine toxicity of the compounds, and in the case of NO donors blood pressure will also be monitored. In addition, the effect of the successful treatments on the brain microcirculation will be assessed by intravital microscopy and the expression of eNOS, nNOS, iNOS and HO-1will be determined. Finally, the compounds will also be tested in an in vitro system of co-culture of human brain endothelial cells and P. falciparum. We expect that to define one or more compounds that can be forwarded for clinical trials. Cerebral malaria (CM) is a major complication of infection by Plasmodium falciparum, causing hundreds of thousands of deaths every year particularly of children under 5 years old. Even receiving anti-malarial treatment, CM shows a 10-20% mortality rate, and survivors may present sequelae. Adjunctive therapies acting in concert with the anti- malarial treatment are then urgently needed to improve the rate and the quality of patient recovery. In this proposal, we intend to develop, using an animal model, adjunctive therapies based on nitric oxide restoration and/or heme detoxification that can be potentially translated into clinical use.

Public Health Relevance

Cerebral malaria (CM) is a major complication of infection by Plasmodium falciparum, causing hundreds of thousands of deaths every year particularly of children under 5 years old. Even receiving anti-malarial treatment, CM shows a 10-20% mortality rate, and survivors may present sequelae. Adjunctive therapies acting in concert with the anti- malarial treatment are then urgently needed to improve the rate and the quality of patient recovery. In this proposal, we intend to develop, using an animal model, adjunctive therapies based on nitric oxide restoration and/or heme detoxification that can be potentially translated into clinical use.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI082610-04
Application #
8311681
Study Section
Special Emphasis Panel (ZAI1-GSM-M (J1))
Program Officer
Rogers, Martin J
Project Start
2009-09-10
Project End
2014-08-31
Budget Start
2012-09-01
Budget End
2014-08-31
Support Year
4
Fiscal Year
2012
Total Cost
$403,704
Indirect Cost
$183,181
Name
La Jolla Institute
Department
Type
DUNS #
114215473
City
San Diego
State
CA
Country
United States
Zip Code
92121
Orjuela-Sanchez, Pamela; Ong, Peng Kai; Zanini, Graziela M et al. (2013) Transdermal glyceryl trinitrate as an effective adjunctive treatment with artemether for late-stage experimental cerebral malaria. Antimicrob Agents Chemother 57:5462-71
Ong, Peng Kai; Melchior, Benoit; Martins, Yuri C et al. (2013) Nitric oxide synthase dysfunction contributes to impaired cerebroarteriolar reactivity in experimental cerebral malaria. PLoS Pathog 9:e1003444
Martins, Yuri C; Clemmer, Leah; Orjuela-Sanchez, Pamela et al. (2013) Slow and continuous delivery of a low dose of nimodipine improves survival and electrocardiogram parameters in rescue therapy of mice with experimental cerebral malaria. Malar J 12:138
Martins, Yuri C; Zanini, Graziela M; Frangos, John A et al. (2012) Efficacy of different nitric oxide-based strategies in preventing experimental cerebral malaria by Plasmodium berghei ANKA. PLoS One 7:e32048
Zanini, Graziela M; Martins, Yuri C; Cabrales, Pedro et al. (2012) S-nitrosoglutathione prevents experimental cerebral malaria. J Neuroimmune Pharmacol 7:477-87
Cabrales, Pedro; Zanini, Graziela M; Meays, Diana et al. (2011) Nitric oxide protection against murine cerebral malaria is associated with improved cerebral microcirculatory physiology. J Infect Dis 203:1454-63
Clemmer, L; Martins, Y C; Zanini, G M et al. (2011) Artemether and artesunate show the highest efficacies in rescuing mice with late-stage cerebral malaria and rapidly decrease leukocyte accumulation in the brain. Antimicrob Agents Chemother 55:1383-90
Bertinaria, Massimo; Guglielmo, Stefano; Rolando, Barbara et al. (2011) Amodiaquine analogues containing NO-donor substructures: synthesis and their preliminary evaluation as potential tools in the treatment of cerebral malaria. Eur J Med Chem 46:1757-67
Zanini, Graziela M; Cabrales, Pedro; Barkho, Wisam et al. (2011) Exogenous nitric oxide decreases brain vascular inflammation, leakage and venular resistance during Plasmodium berghei ANKA infection in mice. J Neuroinflammation 8:66
Alves, F A; Souza, M T; Goncalves, E C et al. (2010) DNA sequencing of 13 cytokine gene fragments of Aotus infulatus and Saimiri sciureus, two non-human primate models for malaria. Cytokine 52:151-5

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