301
|
Affiliation(s)
- Caryn Bern
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
| |
Collapse
|
302
|
de Castro SL, Batista DGJ, Batista MM, Batista W, Daliry A, de Souza EM, Menna-Barreto RFS, Oliveira GM, Salomão K, Silva CF, Silva PB, Soeiro MDNC. Experimental Chemotherapy for Chagas Disease: A Morphological, Biochemical, and Proteomic Overview of Potential Trypanosoma cruzi Targets of Amidines Derivatives and Naphthoquinones. Mol Biol Int 2011; 2011:306928. [PMID: 22091400 PMCID: PMC3195292 DOI: 10.4061/2011/306928] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 02/25/2011] [Accepted: 03/21/2011] [Indexed: 01/31/2023] Open
Abstract
Chagas disease (CD), caused by Trypanosoma cruzi, affects approximately eight million individuals in Latin America and is emerging in nonendemic areas due to the globalisation of immigration and nonvectorial transmission routes. Although CD represents an important public health problem, resulting in high morbidity and considerable mortality rates, few investments have been allocated towards developing novel anti-T. cruzi agents. The available therapy for CD is based on two nitro derivatives (benznidazole (Bz) and nifurtimox (Nf)) developed more than four decades ago. Both are far from ideal due to substantial secondary side effects, limited efficacy against different parasite isolates, long-term therapy, and their well-known poor activity in the late chronic phase. These drawbacks justify the urgent need to identify better drugs to treat chagasic patients. Although several classes of natural and synthetic compounds have been reported to act in vitro and in vivo on T. cruzi, since the introduction of Bz and Nf, only a few drugs, such as allopurinol and a few sterol inhibitors, have moved to clinical trials. This reflects, at least in part, the absence of well-established universal protocols to screen and compare drug activity. In addition, a large number of in vitro studies have been conducted using only epimastigotes and trypomastigotes instead of evaluating compounds' activities against intracellular amastigotes, which are the reproductive forms in the vertebrate host and are thus an important determinant in the selection and identification of effective compounds for further in vivo analysis. In addition, due to pharmacokinetics and absorption, distribution, metabolism, and excretion characteristics, several compounds that were promising in vitro have not been as effective as Nf or Bz in animal models of T. cruzi infection. In the last two decades, our team has collaborated with different medicinal chemistry groups to develop preclinical studies for CD and investigate the in vitro and in vivo efficacy, toxicity, selectivity, and parasite targets of different classes of natural and synthetic compounds. Some of these results will be briefly presented, focusing primarily on diamidines and related compounds and naphthoquinone derivatives that showed the most promising efficacy against T. cruzi.
Collapse
Affiliation(s)
- Solange L. de Castro
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Denise G. J. Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Marcos M. Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Wanderson Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Anissa Daliry
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Elen M. de Souza
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Rubem F. S. Menna-Barreto
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Gabriel M. Oliveira
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Kelly Salomão
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Cristiane F. Silva
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Patricia B. Silva
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| | - Maria de Nazaré C. Soeiro
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, 21040-900 Rio de Janeiro, RJ, Brazil
| |
Collapse
|
303
|
Cencig S, Coltel N, Truyens C, Carlier Y. Parasitic loads in tissues of mice infected with Trypanosoma cruzi and treated with AmBisome. PLoS Negl Trop Dis 2011; 5:e1216. [PMID: 21738811 PMCID: PMC3125148 DOI: 10.1371/journal.pntd.0001216] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 05/13/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Chagas disease is one of the most important public health problems and a leading cause of cardiac failure in Latin America. The currently available drugs to treat T. cruzi infection (benznidazole and nifurtimox) are effective in humans when administered during months. AmBisome (liposomal amphotericin B), already shown efficient after administration for some days in human and experimental infection with Leishmania, has been scarcely studied in T. cruzi infection. AIMS This work investigates the effect of AmBisome treatment, administered in 6 intraperitoneal injections at various times during acute and/or chronic phases of mouse T. cruzi infection, comparing survival rates and parasitic loads in several tissues. METHODOLOGY Quantitative PCR was used to determine parasitic DNA amounts in tissues. Immunosuppressive treatment with cyclophosphamide was used to investigate residual infection in tissues. FINDINGS Administration of AmBisome during the acute phase of infection prevented mice from fatal issue. Parasitaemias (microscopic examination) were reduced in acute phase and undetectable in chronic infection. Quantitative PCR analyses showed significant parasite load reductions in heart, liver, spleen, skeletal muscle and adipose tissues in acute as well as in chronic infection. An earlier administration of AmBisome (one day after parasite inoculation) had a better effect in reducing parasite loads in spleen and liver, whereas repetition of treatment in chronic phase enhanced the parasite load reduction in heart and liver. However, whatever the treatment schedule, cyclophosphamide injections boosted infection to parasite amounts comparable to those observed in acutely infected and untreated mice. CONCLUSIONS Though AmBisome treatment fails to completely cure mice from T. cruzi infection, it impedes mortality and reduces significantly the parasitic loads in most tissues. Such a beneficial effect, obtained by administrating it over a short time, should stimulate studies on using AmBisome in association with other drugs in order to shorten recovery from T. cruzi infection.
Collapse
Affiliation(s)
- Sabrina Cencig
- Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium
| | - Nicolas Coltel
- Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium
| | - Carine Truyens
- Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium
| | - Yves Carlier
- Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium
- * E-mail:
| |
Collapse
|
304
|
Wiggers HJ, Rocha JR, Cheleski J, Montanari CA. Integration of Ligand- and Target-Based Virtual Screening for the Discovery of Cruzain Inhibitors. Mol Inform 2011; 30:565-78. [DOI: 10.1002/minf.201000146] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 04/24/2011] [Indexed: 11/06/2022]
|
305
|
Abstract
Parasitic diseases affect more than 2 billion people globally and cause substantial morbidity and mortality, particularly among the world's poorest people. This overview focuses on the treatment of the major protozoan and helminth infections in humans. Recent developments in antiparasitic therapy include the expansion of artemisinin-based therapies for malaria, new drugs for soil-transmitted helminths and intestinal protozoa, expansion of the indications for antiparasitic drug treatment in patients with Chagas disease, and the use of combination therapy for leishmaniasis and human African trypanosomiasis.
Collapse
Affiliation(s)
| | | | - Brian G. Blackburn
- Address correspondence to Brian G. Blackburn, MD, Stanford University School of Medicine, Division of Infectious Diseases and Geographic Medicine, 300 Pasteur Dr, Grant Bldg, Room S-101, Stanford, CA 94305-5107 (). Individual reprints of this article and a bound reprint of the entire Symposium on Antimicrobial Therapy will be available for purchase from our Web site www.mayoclinicproceedings.com
| |
Collapse
|
306
|
Oppenheimer M, Valenciano AL, Sobrado P. Biosynthesis of galactofuranose in kinetoplastids: novel therapeutic targets for treating leishmaniasis and chagas' disease. Enzyme Res 2011; 2011:415976. [PMID: 21687654 PMCID: PMC3112513 DOI: 10.4061/2011/415976] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/02/2011] [Accepted: 03/14/2011] [Indexed: 12/14/2022] Open
Abstract
Cell surface proteins of parasites play a role in pathogenesis by modulating mammalian cell recognition and cell adhesion during infection. β-Galactofuranose (Galf) is an important component of glycoproteins and glycolipids found on the cell surface of Leishmania spp. and Trypanosoma cruzi. β-Galf-containing glycans have been shown to be important in parasite-cell interaction and protection against oxidative stress. Here, we discuss the role of β-Galf in pathogenesis and recent studies on the Galf-biosynthetic enzymes: UDP-galactose 4′ epimerase (GalE), UDP-galactopyranose mutase (UGM), and UDP-galactofuranosyl transferase (GalfT). The central role in Galf formation, its unique chemical mechanism, and the absence of a homologous enzyme in humans identify UGM as the most attractive drug target in the β-Galf-biosynthetic pathway in protozoan parasites.
Collapse
|
307
|
Wendling APB, Vitelli-Avelar DM, Sathler-Avelar R, Geiger SM, Teixeira-Carvalho A, Gontijo ED, Elói-Santos SM, Martins-Filho OA. The use of IgG antibodies in conventional and non-conventional immunodiagnostic tests for early prognosis after treatment of Chagas disease. J Immunol Methods 2011; 370:24-34. [PMID: 21620855 DOI: 10.1016/j.jim.2011.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 05/09/2011] [Accepted: 05/11/2011] [Indexed: 12/24/2022]
Abstract
Treatment success of chronically infected Chagas disease patients is laborious and a positive prognosis often is made only after repetitive serological and/or parasitological examinations with continuous negative results. Recently, we have developed a non-conventional flow-cytometric method in order to detect immunoglobulin G antibodies against live trypomastigote forms of Trypanosoma cruzi and showed its usefulness in the prognosis of treatment success. In the present study, we investigated the performance of flow-cytometric anti-live trypomastigote IgG antibodies (FC-ALTA) and flow-cytometric anti-fixed epimastigote IgG antibodies (FC-AFEA), as well as conventional serological methods, for early monitoring of benznidazole treated Chagas disease patients, e.g. 5years after treatment. The analysis of individual FC-ALTA reactivity along the titration curve before and after treatment, we were able to show, that between 4% and 13% of treated patients under evaluation presented with reduced serological reactivity and segregated from the other patient groups. Similar results were obtained with semi-quantitative, conventional indirect hemagglutination or indirect immunofluorescence. Our data therefore suggest that the combined use of conventional and non-conventional serological methods could provide more suitable cure criteria in early post-therapeutic prognosis of Chagas disease.
Collapse
Affiliation(s)
- Ana Paula Barbosa Wendling
- Laboratório de Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
308
|
Broniatowska B, Allmendinger A, Kaiser M, Montamat-Sicotte D, Hingley-Wilson S, Lalvani A, Guiry M, Blunden G, Tasdemir D. Antiprotozoal, Antitubercular and Cytotoxic Potential of Cyanobacterial (Blue-Green Algal) Extracts from Ireland. Nat Prod Commun 2011. [DOI: 10.1177/1934578x1100600523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Cyanobacteria (= blue-green algae) are prolific producers of structurally distinct and biologically active metabolites. In the continuation of our search for new sources of anti-infective natural products, we have assessed the in vitro antiprotozoal ( Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani) and antitubercular ( Mycobacterium tuberculosis) potential of samples of two terrestrial cyanobacteria, Nostoc commune (collected when desiccated and wet) and Rivularia biasolettiana. The cytotoxic potential of the extracts was also evaluated against primary L6 cells. Except for T. cruzi and M. tuberculosis, the crude extracts were active against all the organisms tested and showed no toxicity. The crude extracts were then partitioned between n-hexane, chloroform and aqueous methanol and retested against the same panel of pathogens. The chloroform sub-extracts of both N. commune samples showed significant activity against T. b. rhodesiense (IC50 values 2.0 and 3.5 μg/mL) and P. falciparum (IC50S 7.4 and 5.8 μg/mL), with low toxicity. This trend was also true for R. biasolettiana extracts, and its chloroform sub-extract showed notable activity against all parasitic protozoa. There were differences in the biological activity profiles of extracts derived from desiccated and hydrated forms of N. commune. To our knowledge, this is the first study assessing the anti-infective activity of desiccated and hydrated forms of N. commune, as well as R. biasolettiana. Furthermore, the present work reports such biological activity in terrestrial cyanobacteria from Ireland for the first time. These results warrant the further study of Irish terrestrial cyanobacteria as a valuable source of new natural product leads for the treatment of parasitic protozoal infections.
Collapse
Affiliation(s)
- Barbara Broniatowska
- Department of Pharmaceutical and Biological Chemistry, Centre for Pharmacognosy and Phytotherapy, School of Pharmacy, University of London, London WC1N 1AX, UK
| | - Andrea Allmendinger
- Department of Pharmaceutical and Biological Chemistry, Centre for Pharmacognosy and Phytotherapy, School of Pharmacy, University of London, London WC1N 1AX, UK
| | - Marcel Kaiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, CH-4002 Basel, Switzerland
| | - Damien Montamat-Sicotte
- Tuberculosis Research Unit, Department of Respiratory Medicine, National Heart and Lung Institute, Imperial College London, London W2 1PG, UK
| | - Suzie Hingley-Wilson
- Tuberculosis Research Unit, Department of Respiratory Medicine, National Heart and Lung Institute, Imperial College London, London W2 1PG, UK
| | - Ajit Lalvani
- Tuberculosis Research Unit, Department of Respiratory Medicine, National Heart and Lung Institute, Imperial College London, London W2 1PG, UK
| | - Michael Guiry
- AlgaeBase, Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland
| | - Gerald Blunden
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK
| | - Deniz Tasdemir
- Department of Pharmaceutical and Biological Chemistry, Centre for Pharmacognosy and Phytotherapy, School of Pharmacy, University of London, London WC1N 1AX, UK
| |
Collapse
|
309
|
Abstract
PURPOSE OF REVIEW The need for better drugs to treat patients with Chagas disease remains urgent. This review summarizes the advancements in drug development over the past 2 years. RECENT FINDINGS Drug development efforts are almost exclusively occurring as preclinical research, although phase II studies for the antifungal drug, posaconazole, and a prodrug of ravuconazole are being planned. Several recent laboratory investigations demonstrate anti-Trypanosoma cruzi activity of novel small molecules in animal models. These include nonpeptidic cruzain inhibitors, novel inhibitors of the sterol 14α-demethylase enzyme, new compounds (arylimidamides) related to pentamidine, derivatives of nifurtimox, compounds using ruthenium complexes, and several natural products. The recent implementation of a high-throughput screen of more than 300 000 compounds against intracellular T. cruzi amastigotes done at the Broad Institute is an important development, yielding approximately 300 selective inhibitors, many of which may serve as leads for medicinal chemistry efforts. SUMMARY Progress is slow, but recent advancements in both drug development and advocacy for research on neglected diseases are encouraging. Efforts to define a target product profile and to harmonize methodologies for testing drugs for Chagas disease are described herein.
Collapse
|
310
|
Martí-Carvajal AJ, Hidalgo R, Kwong J. Pharmacological interventions for treating heart failure in patients with Chagas cardiomyopathy. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2011. [DOI: 10.1002/14651858.cd009077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
311
|
Belaunzarán ML, Lammel EM, de Isola ELD. Phospholipases a in trypanosomatids. Enzyme Res 2011; 2011:392082. [PMID: 21603263 PMCID: PMC3092542 DOI: 10.4061/2011/392082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 02/07/2011] [Indexed: 12/17/2022] Open
Abstract
Phospholipases are a complex and important group of enzymes widespread in nature, that play crucial roles in diverse biochemical processes and are classified as A1, A2, C, and D. Phospholipases A1 and A2 activities have been linked to pathogenesis in various microorganisms, and particularly in pathogenic protozoa they have been implicated in cell invasion. Kinetoplastids are a group of flagellated protozoa, including extra- and intracellular parasites that cause severe disease in humans and animals. In the present paper, we will mainly focus on the three most important kinetoplastid human pathogens, Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp., giving a perspective of the research done up to now regarding biochemical, biological, and molecular characteristics of Phospholipases A1 and A2 and their contribution to pathogenesis.
Collapse
Affiliation(s)
- María Laura Belaunzarán
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, piso 13, C1121ABG Buenos Aires, Argentina
| | | | | |
Collapse
|
312
|
Rosso VS, Szajnman SH, Malayil L, Galizzi M, Moreno SNJ, Docampo R, Rodriguez JB. Synthesis and biological evaluation of new 2-alkylaminoethyl-1,1-bisphosphonic acids against Trypanosoma cruzi and Toxoplasma gondii targeting farnesyl diphosphate synthase. Bioorg Med Chem 2011; 19:2211-7. [PMID: 21419634 PMCID: PMC3071284 DOI: 10.1016/j.bmc.2011.02.037] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/16/2011] [Accepted: 02/18/2011] [Indexed: 10/18/2022]
Abstract
The effect of long-chain 2-alkylaminoethyl-1,1-bisphosphonates against proliferation of the clinically more relevant form of Trypanosoma cruzi, the etiologic agent of American trypanosomiasis (Chagas' disease), and against tachyzoites of Toxoplasma gondii was investigated. Particularly, compound 26 proved to be an extremely potent inhibitor against the intracellular form of T. cruzi, exhibiting IC(50) values at the nanomolar range. This cellular activity was associated with a strong inhibition of the enzymatic activity of T. cruzi farnesyl diphosphate synthase (TcFPPS), which constitutes a valid target for Chagas' disease chemotherapy. Compound 26 was an effective agent against T. cruzi (amastigotes) exhibiting an IC(50) value of 0.67 μM, while this compound showed an IC(50) value of 0.81 μM against the target enzyme TcFPPS. This drug was less effective against the enzymatic activity of T. cruzi solanesyl diphosphate synthase TcSPPS showing an IC(50) value of 3.2 μM. Interestingly, compound 26 was also very effective against T. gondii (tachyzoites) exhibiting IC(50) values of 6.23 μM. This cellular activity was also related to the inhibition of the enzymatic activity towards the target enzyme TgFPPS (IC(50)=0.093 μM) As bisphosphonate-containing compounds are FDA-approved drugs for the treatment of bone resorption disorders, their potential low toxicity makes them good candidates to control different tropical diseases.
Collapse
Affiliation(s)
- Valeria S Rosso
- Departamento de Química Orgánica and UMYMFOR (CONICET-FCEyN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | | | | | | | | | | | | |
Collapse
|
313
|
Bustamante JM, Tarleton RL. Methodological advances in drug discovery for Chagas disease. Expert Opin Drug Discov 2011; 6:653-661. [PMID: 21712965 DOI: 10.1517/17460441.2011.573782] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION: Chagas disease is the highest impact human infectious disease in Latin America, and the leading worldwide cause of myocarditis. Despite the availability of several compounds that have demonstrated efficacy in limiting the effects of T. cruzi, these compounds are rarely used due to their variable efficacy, substantial side effects and the lack of methodologies for confirming their effectiveness. Furthermore, the development of more efficacious compounds is challenged by limitations of systems for assessing drug efficacy in vitro and in vivo. AREAS COVERED: Herein, the authors review the development of Chagas disease drug discovery methodology, focusing on recent developments in high throughput screening, in vivo testing methods and assessments of efficacy in humans. Particularly, this review documents the significant progress that has taken place over the last 5 years that have paved the way for both target-focused and high-throughput screens of compound libraries. EXPERT OPINION: The tools for in vitro and in vivo screening of anti-T. cruzi compounds have improved dramatically in the last few years and there are now a number of excellent in vivo testing models available; this somewhat alleviates the bottleneck issue of quickly and definitively demonstrating in vivo efficacy in a relevant host animal system. These advances emphasize the potential for additional progress resulting in new treatments for Chagas disease in the coming years. That being said, national and international agencies must improve the coordination of research and development efforts in addition to cultivating the funding sources for the development of these new treatments.
Collapse
Affiliation(s)
- Juan M Bustamante
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, 500 D.W Brooks Dr. S310 Coverdell Center. GA, 30602, USA
| | | |
Collapse
|
314
|
Adesse D, Meirelles Azzam E, de Nazareth L. Meirelles M, Urbina JA, Garzoni LR. Amiodarone inhibits Trypanosoma cruzi infection and promotes cardiac cell recovery with gap junction and cytoskeleton reassembly in vitro. Antimicrob Agents Chemother 2011; 55:203-10. [PMID: 21078932 PMCID: PMC3019665 DOI: 10.1128/aac.01129-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/18/2010] [Accepted: 10/31/2010] [Indexed: 11/20/2022] Open
Abstract
We present the results of the first detailed study of the antiproliferative and ultrastructural effects of amiodarone on Trypanosoma cruzi, the causative agent of Chagas' disease. Moreover, we report the effects of this compound on the recovery of F-actin fibrils, connexin43, and contractility in T. cruzi-infected cardiac myocytes. Amiodarone is the most prescribed class III antiarrhythmic agent and is frequently used for the symptomatic treatment of Chagas' disease patients with cardiac compromise. In addition, recent studies identified its antifungal and antiprotozoal activities, which take place through Ca(2+) homeostasis disruption and ergosterol biosynthesis blockade. We tested different concentrations of amiodarone (2.5 to 10 μM) on infected primary cultures of heart muscle cells and observed a dose- and time-dependent effect on growth of the clinically relevant intracellular amastigote form of T. cruzi. Ultrastructural analyses revealed that amiodarone had a profound effect on intracellular amastigotes, including mitochondrial swelling and disorganization of reservosomes and the kinetoplast and a blockade of amastigote-trypomastigote differentiation. Amiodarone showed no toxic effects on host cells, which recovered their F-actin fibrillar organization, connexin43 distribution, and spontaneous contractility concomitant with the drug-induced eradication of the intracellular parasites. Amiodarone is, therefore, a promising compound for the development of new drugs against T. cruzi.
Collapse
Affiliation(s)
- Daniel Adesse
- Laboratório de Ultraestrutura Celular, Instituto Oswaldo Cruz, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil, Laboratorio de Química Biológica, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Cientificas, Apartado Postal 21.627, Caracas 1020A, Venezuela
| | - Eduardo Meirelles Azzam
- Laboratório de Ultraestrutura Celular, Instituto Oswaldo Cruz, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil, Laboratorio de Química Biológica, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Cientificas, Apartado Postal 21.627, Caracas 1020A, Venezuela
| | - Maria de Nazareth L. Meirelles
- Laboratório de Ultraestrutura Celular, Instituto Oswaldo Cruz, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil, Laboratorio de Química Biológica, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Cientificas, Apartado Postal 21.627, Caracas 1020A, Venezuela
| | - Julio A. Urbina
- Laboratório de Ultraestrutura Celular, Instituto Oswaldo Cruz, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil, Laboratorio de Química Biológica, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Cientificas, Apartado Postal 21.627, Caracas 1020A, Venezuela
| | - Luciana R. Garzoni
- Laboratório de Ultraestrutura Celular, Instituto Oswaldo Cruz, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil, Laboratorio de Química Biológica, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Cientificas, Apartado Postal 21.627, Caracas 1020A, Venezuela
| |
Collapse
|
315
|
|
316
|
Shakur Y, de Koning HP, Ke H, Kambayashi J, Seebeck T. Therapeutic potential of phosphodiesterase inhibitors in parasitic diseases. Handb Exp Pharmacol 2011:487-510. [PMID: 21695653 DOI: 10.1007/978-3-642-17969-3_20] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Protozoan parasites of the order kinetoplastida are the causative agents of three of the world's most important neglected human diseases: African trypanosomiasis, American trypanosomiasis, and leishmaniasis. Current therapies are limited, with some treatments having serious and sometimes lethal side effects. The growing number of cases that are refractory to treatment is also of concern. With few new drugs in development, there is an unmet medical need for new, more effective, and safer medications. Recent studies employing genetic and pharmacological techniques have begun to shed light on the role of the cyclic nucleotide phosphodiesterases in the life cycle of these pathogens and suggest that these important regulators of cyclic nucleotide signaling may be promising new targets for the treatment of parasitic diseases.
Collapse
Affiliation(s)
- Yasmin Shakur
- Otsuka Maryland Medicinal Laboratories Inc, 9900 Medical Center Drive, Rockville, MD 20850, USA.
| | | | | | | | | |
Collapse
|
317
|
Goldenberg S, Ávila AR. Aspects of Trypanosoma cruzi stage differentiation. ADVANCES IN PARASITOLOGY 2011; 75:285-305. [PMID: 21820561 DOI: 10.1016/b978-0-12-385863-4.00013-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Trypanosoma cruzi alternates between different morphological and functional types during its life cycle. Since the discovery of this parasite at the beginning of the twentieth century, efforts have been made to determine the basis of its pathogenesis in the course of Chagas disease and its biochemical constituents. There has also been work to develop tools and strategies for prophylaxis of the important disease caused by these parasites which affects millions of people in Latin America. The identification of axenic conditions allowing T. cruzi growth and differentiation has led to the identification and characterization of stage-specific antigens as well as a better characterization of the biological properties and biochemical particularities of each individual developmental stage. The recent availability of genomic data should pave the way to new progress in our knowledge of the biology and pathogenesis of T. cruzi. This review addresses the differentiation and major stage-specific antigens of T. cruzi and attempts to describe the complexity of the parasite and of the disease it causes.
Collapse
|
318
|
Trypanocidal activity and selectivity in vitro of aromatic amidine compounds upon bloodstream and intracellular forms of Trypanosoma cruzi. Exp Parasitol 2010; 127:429-35. [PMID: 20971106 DOI: 10.1016/j.exppara.2010.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/05/2010] [Accepted: 10/14/2010] [Indexed: 11/20/2022]
Abstract
Trypanosoma cruzi is the etiological agent of Chagas disease, an important neglected illness affecting about 12-14 million people in endemic areas of Latin America. The chemotherapy of Chagas disease is quite unsatisfactory mainly due to its poor efficacy especially during the later chronic phase and the considerable well-known side effects. These facts emphasize the need to search for find new drugs. Diamidines and related compounds are minor groove binders of DNA at AT-rich sites and present excellent anti-trypanosomal activity. In the present study, six novel aromatic amidine compounds (arylimidamides and diamidines) were tested in vitro to determine activity against the infective and intracellular stages of T. cruzi, which are responsible for sustaining the infection in the mammalian hosts. In addition, their selectivity and toxicity towards primary cultures of cardiomyocyte were evaluated since these cells represent important targets of infection and inflammation in vivo. The aromatic amidines were active against T. cruzi in vitro, the arylimidamide DB1470 was the most effective compound presenting a submicromolar LD(50) values, good selectivity index, and good activity at 4 °C in the presence of blood constituents. Our results further justify trypanocidal screening assays with these classes of compounds both in vitro and in vivo in experimental models of T. cruzi infection.
Collapse
|
319
|
The endless race between Trypanosoma cruzi and host immunity: lessons for and beyond Chagas disease. Expert Rev Mol Med 2010; 12:e29. [PMID: 20840799 DOI: 10.1017/s1462399410001560] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Infection with the protozoan parasite Trypanosoma cruzi, the agent of Chagas disease, is characterised by a variable clinical course - from symptomless cases to severe chronic disease with cardiac and/or gastrointestinal involvement. The variability in disease outcome has been attributed to host responses as well as parasite heterogeneity. In this article, we review studies indicating the importance of immune responses as key determinants of host resistance to T. cruzi infection and the pathogenesis of Chagas disease. Particular attention is given to recent studies defining the role of cognate innate immune receptors and immunodominant CD8+ T cells that recognise parasite components - both crucial for host-parasite interaction and disease outcome. In light of these studies we speculate about parasite strategies that induce a strong and long-lasting T-cell-mediated immunity but at the same time allow persistence of the parasite in the vertebrate host. We also discuss what we have learned from these studies for increasing our understanding of Chagas pathogenesis and for the design of new strategies to prevent the development of Chagas disease. Finally, we highlight recent studies employing a genetically engineered attenuated T. cruzi strain as a vaccine shuttle that elicits potent T cell responses specific to a tumour antigen and protective immunity against a syngeneic melanoma cell line.
Collapse
|
320
|
Antileishmanial and antitrypanosomal activities of the 8-aminoquinoline tafenoquine. Antimicrob Agents Chemother 2010; 54:5356-8. [PMID: 20837750 DOI: 10.1128/aac.00985-10] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 8-aminoquinoline tafenoquine showed significant in vitro activity against Leishmania species, including L. donovani amastigotes in macrophages, with 50% inhibitory concentrations (IC(50)s) between 0.1 and 4.0 μM for both pentavalent antimony (SbV)-sensitive and SbV-resistant strains and by oral administration in BALB/c mice, with 50% effective dose (ED(50)) values of 1.2 to 3.5 mg/kg for 5 days. Tafenoquine was less active against intracellular Trypanosoma cruzi amastigotes, with an IC(50) of 21.9 μM.
Collapse
|
321
|
In vitro and in vivo high-throughput assays for the testing of anti-Trypanosoma cruzi compounds. PLoS Negl Trop Dis 2010; 4:e740. [PMID: 20644616 PMCID: PMC2903469 DOI: 10.1371/journal.pntd.0000740] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 05/27/2010] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The two available drugs for treatment of T. cruzi infection, nifurtimox and benznidazole (BZ), have potential toxic side effects and variable efficacy, contributing to their low rate of use. With scant economic resources available for antiparasitic drug discovery and development, inexpensive, high-throughput and in vivo assays to screen potential new drugs and existing compound libraries are essential. METHODS In this work, we describe the development and validation of improved methods to test anti-T. cruzi compounds in vitro and in vivo using parasite lines expressing the firefly luciferase (luc) or the tandem tomato fluorescent protein (tdTomato). For in vitro assays, the change in fluorescence intensity of tdTomato-expressing lines was measured as an indicator of parasite replication daily for 4 days and this method was used to identify compounds with IC(50) lower than that of BZ. FINDINGS This method was highly reproducible and had the added advantage of requiring relatively low numbers of parasites and no additional indicator reagents, enzymatic post-processes or laborious visual counting. In vivo, mice were infected in the footpads with fluorescent or bioluminescent parasites and the signal intensity was measured as a surrogate of parasite load at the site of infection before and after initiation of drug treatment. Importantly, the efficacy of various drugs as determined in this short-term (<2 weeks) assay mirrored that of a 40 day treatment course. CONCLUSION These methods should make feasible broader and higher-throughput screening programs needed to identify potential new drugs for the treatment of T. cruzi infection and for their rapid validation in vivo.
Collapse
|
322
|
Hotez PJ, Pecoul B. "Manifesto" for advancing the control and elimination of neglected tropical diseases. PLoS Negl Trop Dis 2010; 4:e718. [PMID: 20520793 PMCID: PMC2876053 DOI: 10.1371/journal.pntd.0000718] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Peter J. Hotez
- Department of Microbiology, Immunology, and Tropical Medicine, George Washington University and Sabin Vaccine Institute, Washington, D. C., United States of America
- * E-mail: (PJH); (BP)
| | - Bernard Pecoul
- DNDi (Drugs for Neglected Diseases Initiative), Geneva, Switzerland
- * E-mail: (PJH); (BP)
| |
Collapse
|
323
|
Jacobs RT, Ding C. Recent Advances in Drug Discovery for Neglected Tropical Diseases Caused by Infective Kinetoplastid Parasites. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2010. [DOI: 10.1016/s0065-7743(10)45017-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|