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Coleman B, Smith BR, Kapoor R, Proschan MA, Sereti I, Hammoud DA, Kovacs JA. Persistence of Human Immunodeficiency Virus-Associated Cerebral Toxoplasmosis Lesions in Successfully Treated Patients Receiving Combination Antiretroviral Therapy. Open Forum Infect Dis 2023; 10:ofad208. [PMID: 37213420 PMCID: PMC10199119 DOI: 10.1093/ofid/ofad208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/14/2023] [Indexed: 05/23/2023] Open
Abstract
Background Toxoplasmic encephalitis (TE) is a life-threatening complication of people with human immunodeficiency virus (PWH) with severe immunodeficiency, especially those with a CD4+ T-cell count <100 cells/µL. Following a clinical response to anti-Toxoplasma therapy, and immune reconstitution after initiation of combination antiretroviral therapy (ART), anti-Toxoplasma therapy can be discontinued with a low risk of relapse. Methods To better understand the evolution of magnetic resonance imaging (MRI)-defined TE lesions in PWH receiving ART, we undertook a retrospective study of PWH initially seen at the National Institutes of Health between 2001 and 2012, who had at least 2 serial MRI scans. Lesion size and change over time were calculated and correlated with clinical parameters. Results Among 24 PWH with TE and serial MRI scans, only 4 had complete clearance of lesions at the last MRI (follow-up, 0.09-5.8 years). Of 10 PWH off all anti-Toxoplasma therapy (median, 3.2 years after TE diagnosis), 6 had persistent MRI enhancement. In contrast, all 5 PWH seen in a pre-ART era study who were followed for >6 months had complete clearance of lesions. TE lesion area at diagnosis was associated with the absolute change in area (P < .0001). Conclusions Contrast enhancement can persist even when TE has been successfully treated and anti-Toxoplasma therapy has been stopped, highlighting the need to consider diagnostic alternatives in successfully treated patients with immune reconstitution presenting with new neurologic symptoms.
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Affiliation(s)
- Benjamin Coleman
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Bryan R Smith
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Rama Kapoor
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael A Proschan
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Irini Sereti
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Dima A Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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Alday PH, Nilsen A, Doggett JS. Structure-activity relationships of Toxoplasma gondii cytochrome bc1 inhibitors. Expert Opin Drug Discov 2022; 17:997-1011. [PMID: 35772172 PMCID: PMC9561756 DOI: 10.1080/17460441.2022.2096588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/28/2022] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Toxoplasma gondii is a prolific apicomplexan parasite that infects human and nonhuman animals worldwide and can cause severe brain and eye disease. Safer, more effective therapies for toxoplasmosis are needed. Cytochrome bc1 inhibitors are remarkably effective against toxoplasmosis and other apicomplexan-caused diseases. AREAS COVERED This work reviews T. gondii cytochrome bc1 inhibitors. Emphasis is placed on the structure-activity relationships of these inhibitors with regard to efficacy, pharmacokinetics, selectivity of T. gondii cytochrome bc1 over host, safety, and potential therapeutic strategies. EXPERT OPINION Cytochrome bc1 inhibitors are highly promising compounds for toxoplasmosis that have been effective in clinical and preclinical studies. Clinical experience with atovaquone previously validated cytochrome bc1 as a tractable drug target and, over the past decade, optimization of cytochrome bc1 inhibitors has resulted in improved bioavailability, metabolic stability, potency, blood-brain barrier penetration, and selectivity for the T. gondii cytochrome bc1 over the mammalian bc1. Recent studies have demonstrated preclinical safety, identified novel therapeutic strategies for toxoplasmosis using synergistic combinations or long-acting administration and provided insight into their role in chronic infection. This research has identified drug candidates that are more effective than clinically used drugs in preclinical measures of efficacy.
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Affiliation(s)
- Phil Holland Alday
- Portland VA Medical Center, Portland, Oregon, USA
- Oregon Health & Science University, Portland, Oregon, USA
| | - Aaron Nilsen
- Portland VA Medical Center, Portland, Oregon, USA
- Oregon Health & Science University, Portland, Oregon, USA
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3
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Tan S, Tong WH, Vyas A. Impact of Plant-Based Foods and Nutraceuticals on Toxoplasma gondii Cysts: Nutritional Therapy as a Viable Approach for Managing Chronic Brain Toxoplasmosis. Front Nutr 2022; 9:827286. [PMID: 35284438 PMCID: PMC8914227 DOI: 10.3389/fnut.2022.827286] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/31/2022] [Indexed: 12/13/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite that mainly infects warm-blooded animals including humans. T. gondii can encyst and persist chronically in the brain, leading to a broad spectrum of neurological sequelae. Despite the associated health threats, no clinical drug is currently available to eliminate T. gondii cysts. In a continuous effort to uncover novel therapeutic agents for these cysts, the potential of nutritional products has been explored. Herein, we describe findings from in vitro and in vivo studies that support the efficacy of plant-based foods and nutraceuticals against brain cyst burden and cerebral pathologies associated with chronic toxoplasmosis. Finally, we discuss strategies to increase the translatability of preclinical studies and nutritional products to address whether nutritional therapy can be beneficial for coping with chronic T. gondii infections in humans.
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Rodriguez-Rodriguez BA, Noval MG, Kaczmarek ME, Jang KK, Thannickal SA, Cifuentes Kottkamp A, Brown RS, Kielian M, Cadwell K, Stapleford KA. Atovaquone and Berberine Chloride Reduce SARS-CoV-2 Replication In Vitro. Viruses 2021; 13:v13122437. [PMID: 34960706 PMCID: PMC8706021 DOI: 10.3390/v13122437] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/24/2021] [Accepted: 12/01/2021] [Indexed: 01/05/2023] Open
Abstract
Epidemic RNA viruses seem to arise year after year leading to countless infections and devastating disease. SARS-CoV-2 is the most recent of these viruses, but there will undoubtedly be more to come. While effective SARS-CoV-2 vaccines are being deployed, one approach that is still missing is effective antivirals that can be used at the onset of infections and therefore prevent pandemics. Here, we screened FDA-approved compounds against SARS-CoV-2. We found that atovaquone, a pyrimidine biosynthesis inhibitor, is able to reduce SARS-CoV-2 infection in human lung cells. In addition, we found that berberine chloride, a plant-based compound used in holistic medicine, was able to inhibit SARS-CoV-2 infection in cells through direct interaction with the virion. Taken together, these studies highlight potential avenues of antiviral development to block emerging viruses. Such proactive approaches, conducted well before the next pandemic, will be essential to have drugs ready for when the next emerging virus hits.
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Affiliation(s)
- Bruno A. Rodriguez-Rodriguez
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; (B.A.R.-R.); (M.G.N.); (M.E.K.); (K.K.J.); (S.A.T.); (K.C.)
| | - Maria G. Noval
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; (B.A.R.-R.); (M.G.N.); (M.E.K.); (K.K.J.); (S.A.T.); (K.C.)
| | - Maria E. Kaczmarek
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; (B.A.R.-R.); (M.G.N.); (M.E.K.); (K.K.J.); (S.A.T.); (K.C.)
| | - Kyung Ku Jang
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; (B.A.R.-R.); (M.G.N.); (M.E.K.); (K.K.J.); (S.A.T.); (K.C.)
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Sara A. Thannickal
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; (B.A.R.-R.); (M.G.N.); (M.E.K.); (K.K.J.); (S.A.T.); (K.C.)
| | | | - Rebecca S. Brown
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (R.S.B.); (M.K.)
| | - Margaret Kielian
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (R.S.B.); (M.K.)
| | - Ken Cadwell
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; (B.A.R.-R.); (M.G.N.); (M.E.K.); (K.K.J.); (S.A.T.); (K.C.)
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
- Department of Medicine, New York University Grossman School of Medicine, New York, NY 10016, USA;
| | - Kenneth A. Stapleford
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA; (B.A.R.-R.); (M.G.N.); (M.E.K.); (K.K.J.); (S.A.T.); (K.C.)
- Correspondence:
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5
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Carter-Timofte ME, Arulanandam R, Kurmasheva N, Fu K, Laroche G, Taha Z, van der Horst D, Cassin L, van der Sluis RM, Palermo E, Di Carlo D, Jacobs D, Maznyi G, Azad T, Singaravelu R, Ren F, Hansen AL, Idorn M, Holm CK, Jakobsen MR, van Grevenynghe J, Hiscott J, Paludan SR, Bell JC, Seguin J, Sabourin LA, Côté M, Diallo JS, Alain T, Olagnier D. Antiviral Potential of the Antimicrobial Drug Atovaquone against SARS-CoV-2 and Emerging Variants of Concern. ACS Infect Dis 2021; 7:3034-3051. [PMID: 34658235 PMCID: PMC8547501 DOI: 10.1021/acsinfecdis.1c00278] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Indexed: 12/22/2022]
Abstract
The antimicrobial medication malarone (atovaquone/proguanil) is used as a fixed-dose combination for treating children and adults with uncomplicated malaria or as chemoprophylaxis for preventing malaria in travelers. It is an inexpensive, efficacious, and safe drug frequently prescribed around the world. Following anecdotal evidence from 17 patients in the provinces of Quebec and Ontario, Canada, suggesting that malarone/atovaquone may present some benefits in protecting against COVID-19, we sought to examine its antiviral potential in limiting the replication of SARS-CoV-2 in cellular models of infection. In VeroE6 expressing human TMPRSS2 and human lung Calu-3 epithelial cells, we show that the active compound atovaquone at micromolar concentrations potently inhibits the replication of SARS-CoV-2 and other variants of concern including the alpha, beta, and delta variants. Importantly, atovaquone retained its full antiviral activity in a primary human airway epithelium cell culture model. Mechanistically, we demonstrate that the atovaquone antiviral activity against SARS-CoV-2 is partially dependent on the expression of TMPRSS2 and that the drug can disrupt the interaction of the spike protein with the viral receptor, ACE2. Additionally, spike-mediated membrane fusion was also reduced in the presence of atovaquone. In the United States, two clinical trials of atovaquone administered alone or in combination with azithromycin were initiated in 2020. While we await the results of these trials, our findings in cellular infection models demonstrate that atovaquone is a potent antiviral FDA-approved drug against SARS-CoV-2 and other variants of concern in vitro.
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Affiliation(s)
| | - Rozanne Arulanandam
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
| | - Naziia Kurmasheva
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
| | - Kathy Fu
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Center for Infection, Immunity, and Inflammation,
University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Ottawa Institute of Systems
Biology, Ottawa, Ontario K1H 8L1, Canada
| | - Geneviève Laroche
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Center for Infection, Immunity, and Inflammation,
University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Ottawa Institute of Systems
Biology, Ottawa, Ontario K1H 8L1, Canada
| | - Zaid Taha
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
| | | | - Lena Cassin
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
| | - Renée M. van der Sluis
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
- Aarhus Institute of Advanced Studies, Aarhus
University, Aarhus 8000, Denmark
| | - Enrico Palermo
- Istituto Pasteur Italia-Cenci Bolognetti
Foundation, Viale Regina Elena 291, Rome 00161,
Italy
| | - Daniele Di Carlo
- Istituto Pasteur Italia-Cenci Bolognetti
Foundation, Viale Regina Elena 291, Rome 00161,
Italy
| | - David Jacobs
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Center for Infection, Immunity, and Inflammation,
University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Ottawa Institute of Systems
Biology, Ottawa, Ontario K1H 8L1, Canada
| | - Glib Maznyi
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
| | - Taha Azad
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
| | - Ragunath Singaravelu
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
| | - Fanghui Ren
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
| | | | - Manja Idorn
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
| | - Christian K. Holm
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
| | | | - Julien van Grevenynghe
- Institut National de la Recherche
Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie,
Laval, Québec H7V 1B7, Canada
| | - John Hiscott
- Istituto Pasteur Italia-Cenci Bolognetti
Foundation, Viale Regina Elena 291, Rome 00161,
Italy
| | - Søren R. Paludan
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
| | - John C. Bell
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
| | - Jean Seguin
- CCFP, Dipl. Sport Med., CareMedics
McArthur, 311 McArthur Avenue suite 103, Ottawa, Ontario K1L 8M3,
Canada
| | - Luc A. Sabourin
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
- Department of Cellular and Molecular Medicine,
University of Ottawa, Ottawa, Ontario K1H 8M5,
Canada
| | - Marceline Côté
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Center for Infection, Immunity, and Inflammation,
University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Ottawa Institute of Systems
Biology, Ottawa, Ontario K1H 8L1, Canada
| | - Jean-Simon Diallo
- Center for Innovative Cancer Research,
Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6,
Canada
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
| | - Tommy Alain
- Department of Biochemistry, Microbiology, and
Immunology, University of Ottawa, Ottawa, Ontario K1H 8L1,
Canada
- Children’s Hospital of Eastern
Ontario Research Institute, Ottawa, Ontario K1H 8L1,
Canada
| | - David Olagnier
- Department of Biomedicine, Aarhus
University, Aarhus C 8000, Denmark
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6
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Jacobs K, Charvat R, Arrizabalaga G. Identification of Fis1 Interactors in Toxoplasma gondii Reveals a Novel Protein Required for Peripheral Distribution of the Mitochondrion. mBio 2020; 11:e02732-19. [PMID: 32047127 PMCID: PMC7018656 DOI: 10.1128/mbio.02732-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 12/23/2019] [Indexed: 12/26/2022] Open
Abstract
Toxoplasma gondii's single mitochondrion is very dynamic and undergoes morphological changes throughout the parasite's life cycle. During parasite division, the mitochondrion elongates, enters the daughter cells just prior to cytokinesis, and undergoes fission. Extensive morphological changes also occur as the parasite transitions from the intracellular environment to the extracellular environment. We show that treatment with the ionophore monensin causes reversible constriction of the mitochondrial outer membrane and that this effect depends on the function of the fission-related protein Fis1. We also observed that mislocalization of the endogenous Fis1 causes a dominant-negative effect that affects the morphology of the mitochondrion. As this suggests that Fis1 interacts with proteins critical for maintenance of mitochondrial structure, we performed various protein interaction trap screens. In this manner, we identified a novel outer mitochondrial membrane protein, LMF1, which is essential for positioning of the mitochondrion in intracellular parasites. Normally, while inside a host cell, the parasite mitochondrion is maintained in a lasso shape that stretches around the parasite periphery where it has regions of coupling with the parasite pellicle, suggesting the presence of membrane contact sites. In intracellular parasites lacking LMF1, the mitochondrion is retracted away from the pellicle and instead is collapsed, as normally seen only in extracellular parasites. We show that this phenotype is associated with defects in parasite fitness and mitochondrial segregation. Thus, LMF1 is necessary for mitochondrial association with the parasite pellicle during intracellular growth, and proper mitochondrial morphology is a prerequisite for mitochondrial division.IMPORTANCEToxoplasma gondii is an opportunistic pathogen that can cause devastating tissue damage in the immunocompromised and congenitally infected. Current therapies are not effective against all life stages of the parasite, and many cause toxic effects. The single mitochondrion of this parasite is a validated drug target, and it changes its shape throughout its life cycle. When the parasite is inside a cell, the mitochondrion adopts a lasso shape that lies in close proximity to the pellicle. The functional significance of this morphology is not understood and the proteins involved are currently not known. We have identified a protein that is required for proper mitochondrial positioning at the periphery and that likely plays a role in tethering this organelle. Loss of this protein results in dramatic changes to the mitochondrial morphology and significant parasite division and propagation defects. Our results give important insight into the molecular mechanisms regulating mitochondrial morphology.
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Affiliation(s)
- Kylie Jacobs
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Robert Charvat
- Department of Biology, University of Findlay, Findlay, Ohio, USA
| | - Gustavo Arrizabalaga
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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7
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Chorlton SD. Adjunctive bradyzoite-directed therapy for reducing complications of congenital toxoplasmosis. Med Hypotheses 2019; 133:109376. [PMID: 31472369 DOI: 10.1016/j.mehy.2019.109376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/18/2019] [Indexed: 11/25/2022]
Abstract
Congenital toxoplasmosis is caused by in utero infection of the fetus with the intracellular parasite Toxoplasma gondii. Upon infection, the parasite forms life-long cysts in fetal brain and eyes which are resistant to the currently accepted therapy of pyrimethamine and sulfadiazine. These cysts commonly reactivate later in life causing chorioretinitis and visual impairment, and rarely cause neurological complications. I hypothesize that adjunctive, bradyzoite-directed therapies have the potential to alleviate a significant burden of disease by reducing cyst burden in neonatal brain and eyes. Atovaquone is perhaps the most promising drug for further evaluation given its low side-effect profile, established safety, and efficacy in animal models reducing cyst burden. Very limited observational data in humans suggests atovaquone may prevent Toxoplasma-associated chorioretinitis recurrence. Clinical trials are needed to evaluate it and other potential drugs as adjunctive treatment in congenital toxoplasmosis.
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Affiliation(s)
- Samuel D Chorlton
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada.
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8
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Lewis PO, Cluck DB, Huffman JD, Ogle AP, Brown SD. Stability of a pyrimethamine suspension compounded from bulk powder. Am J Health Syst Pharm 2019; 74:2060-2064. [PMID: 29222363 DOI: 10.2146/ajhp160551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Development of a stability-indicating high-performance liquid chromatography (HPLC) method for pyrimethamine analysis, with subsequent application of that method to assess the 90-day stability of a pyrimethamine suspension compounded from bulk USP-grade pyrimethamine powder, is described. METHODS A stability-indicating method of HPLC with ultraviolet detection specific to pyrimethamine was developed according to pharmacopeial recommendations and validated. The method was applied to investigate the stability of a 2-mg/mL pyrimethamine suspension in a vehicle consisting of Ora-Plus and Ora-Sweet (Perrigo) over a period of 90 days. Three replicate test preparations were stored at room temperature or refrigerated at 4.3-5.2 °C, and samples were analyzed in duplicate immediately after preparation and on study days 1, 2, 4, 7, 10, 14, 21, 30, 48, 60, 75, and 90. RESULTS The 2-mg/mL suspension of pyrimethamine in Ora-Plus and Ora-Sweet retained 90-110% of the labeled potency to 90 days at both temperature ranges. However, color changes in the samples stored at room temperature observed at day 60 indicated that a beyond-use date less than 90 days from the preparation date should be specified when the suspension is to be stored at room temperature. CONCLUSION The study demonstrated that USP-grade pyrimethamine powder can be formulated as a 2-mg/mL suspension in a vehicle of Ora-Plus and Ora-Sweet and is stable when stored at room temperature and when refrigerated, in amber plastic bottles, for 48 and 90 days, respectively.
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Affiliation(s)
- Paul O Lewis
- Department of Pharmacy, Johnson City Medical Center, Johnson City, TN
| | - David B Cluck
- Department of Pharmacy Practice, Bill Gatton College of Pharmacy at East Tennessee State University, Johnson City, TN
| | - Jessica D Huffman
- Bill Gatton College of Pharmacy at East Tennessee State University, Johnson City, TN
| | - Amanda P Ogle
- Bill Gatton College of Pharmacy at East Tennessee State University, Johnson City, TN
| | - Stacy D Brown
- Department of Pharmaceutical Sciences, Bill Gatton College of Pharmacy at East Tennessee State University, Johnson City, TN
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9
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Atovaquone Inhibits Arbovirus Replication through the Depletion of Intracellular Nucleotides. J Virol 2019; 93:JVI.00389-19. [PMID: 30894466 DOI: 10.1128/jvi.00389-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 03/13/2019] [Indexed: 12/11/2022] Open
Abstract
Arthropod-borne viruses represent a significant public health threat worldwide, yet there are few antiviral therapies or prophylaxes targeting these pathogens. In particular, the development of novel antivirals for high-risk populations such as pregnant women is essential to prevent devastating disease such as that which was experienced with the recent outbreak of Zika virus (ZIKV) in the Americas. One potential avenue to identify new and pregnancy-acceptable antiviral compounds is to repurpose well-known and widely used FDA-approved drugs. In this study, we addressed the antiviral role of atovaquone, an FDA Pregnancy Category C drug and pyrimidine biosynthesis inhibitor used for the prevention and treatment of parasitic infections. We found that atovaquone was able to inhibit ZIKV and chikungunya virus virion production in human cells and that this antiviral effect occurred early during infection at the initial steps of viral RNA replication. Moreover, we were able to complement viral replication and virion production with the addition of exogenous pyrimidine nucleosides, indicating that atovaquone functions through the inhibition of the pyrimidine biosynthesis pathway to inhibit viral replication. Finally, using an ex vivo human placental tissue model, we found that atovaquone could limit ZIKV infection in a dose-dependent manner, providing evidence that atovaquone may function as an antiviral in humans. Taken together, these studies suggest that atovaquone could be a broad-spectrum antiviral drug and a potential attractive candidate for the prophylaxis or treatment of arbovirus infection in vulnerable populations, such as pregnant women and children.IMPORTANCE The ability to protect vulnerable populations such as pregnant women and children from Zika virus and other arbovirus infections is essential to preventing the devastating complications induced by these viruses. One class of antiviral therapies may lie in known pregnancy-acceptable drugs that have the potential to mitigate arbovirus infections and disease, yet this has not been explored in detail. In this study, we show that the common antiparasitic drug atovaquone inhibits arbovirus replication through intracellular nucleotide depletion and can impair ZIKV infection in an ex vivo human placental explant model. Our study provides a novel function for atovaquone and highlights that the rediscovery of pregnancy-acceptable drugs with potential antiviral effects can be the key to better addressing the immediate need for treating viral infections and preventing potential birth complications and future disease.
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10
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Vetrivel U, Nagarajan H. Deciphering ophthalmic adaptive inhibitors targeting RON4 of Toxoplasma gondii: An integrative in silico approach. Life Sci 2018; 213:82-93. [DOI: 10.1016/j.lfs.2018.10.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/09/2018] [Accepted: 10/11/2018] [Indexed: 02/06/2023]
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11
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Montazeri M, Mehrzadi S, Sharif M, Sarvi S, Tanzifi A, Aghayan SA, Daryani A. Drug Resistance in Toxoplasma gondii. Front Microbiol 2018; 9:2587. [PMID: 30420849 PMCID: PMC6215853 DOI: 10.3389/fmicb.2018.02587] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 10/10/2018] [Indexed: 12/12/2022] Open
Abstract
Toxoplasma gondii (T. gondii) is a global protozoan parasite infecting up to one-third of the world population. Pyrimethamine (PYR) and sulfadiazine (SDZ) are the most widely used drugs for treatment of toxoplasmosis; however, several failure cases have been recorded as well; suggesting the existence of drug resistant strains. This review aims to give a systematic and comprehensive understanding of drug resistance in T. gondii including mechanisms of resistance and sites of drug action in parasite. Analogous amino acid substitutions in the Toxoplasma enzyme were identified to confer PYR resistance. Moreover, resistance to clindamycin, spiramycin, and azithromycin is encoded in the rRNA genes of T. gondii. However, T. gondii SDZ resistance mechanism has not been proved yet. Recently there has been a slight increase in SDZ resistance. That is why the majority of studies were carried out using SDZ. Six strains resistant to SDZ were found in clinical cases between 2013 and 2017 which among Brazilian T. gondii isolates, TgCTBr11, Ck3, and Pg1 were identified in human toxoplasmosis, as well as in livestock intended for human consumption. In conclusion, recent experimental studies in clinical cases have clearly shown that drug resistance in Toxoplasma is ongoing. Thus, establishing a more effective therapeutic scheme in the treatment of toxoplasmosis is critically needed. The emergence of T. gondii strains resistant to current drugs, reviewed here, represents a concern not only for treatment failure but also for increased clinical severity in immunocompromised patients. To improve the therapeutic outcome in patients, a greater understanding of the exact mechanisms of drug resistance in T. gondii should be developed. Thus, monitoring the presence of resistant parasites, in food products, would seem a prudent public health program.
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Affiliation(s)
- Mahbobeh Montazeri
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Saeed Mehrzadi
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mehdi Sharif
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Parasitology, School of Medicine, Sari Branch, Islamic Azad University, Sari, Iran
| | - Shahabeddin Sarvi
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Parasitology, Sari Medical School, Mazandaran University of Medical Sciences, Sari, Iran
| | - Asal Tanzifi
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Sargis A Aghayan
- Laboratory of Zoology, Research Institute of Biology, Yerevan State University, Yerevan, Armenia
| | - Ahmad Daryani
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Parasitology, Sari Medical School, Mazandaran University of Medical Sciences, Sari, Iran
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12
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Clark HL, Minns MS, Sun Y, de Jesus T, Ghannoum MG, Pearlman E. Atovaquone Impairs Growth of Aspergillus and Fusarium Keratitis Isolates by Modulating Mitochondrial Function and Zinc Homeostasis. Invest Ophthalmol Vis Sci 2018; 59:1589-1598. [PMID: 29625485 PMCID: PMC5863689 DOI: 10.1167/iovs.17-22585] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose Aspergillus and Fusarium molds cause blinding corneal infections as a consequence of ocular trauma and in association with contact lens wear. As these fungi require zinc for fungal growth, we examined the effect of atovaquone, a ubiquinone analog that disrupts zinc homeostasis, on fungal growth in vitro and in vivo. Methods In vitro: Aspergillus and Fusarium germinating conidia were incubated overnight with atovaquone, and hyphal growth was measured by fluorimetry. In vivo: C57BL/6 mouse corneas were infected with Aspergillus or Fusarium conidia. Atovaquone was added topically and corneal opacification and fungal growth were quantified. Results Atovaquone has antifungal activity against Aspergillus and Fusarium clinical isolates, with Fusarium species being more sensitive to atovaquone than Aspergillus species. Atovaquone also reduced labile intracellular zinc levels and increased the sensitivity of Aspergillus to metal shock. Atovaquone reduced vacuolar acidification, which regulates storage of intracellular free zinc, and also acted synergistically with voriconazole and itraconazole to kill hyphae. Furthermore, mitochondrial potential and ATP production were reduced in both Aspergillus and Fusarium following atovaquone treatment. Finally, topical application of atovaquone to the ocular surface significantly inhibited fungal growth and corneal opacification in murine models of fungal keratitis. Conclusions These studies demonstrate that atovaquone has pronounced in vitro and in vivo antifungal activity against filamentous fungi by disrupting both metal homeostasis and mitochondrial function, and therefore has potential as a novel antifungal agent.
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Affiliation(s)
- Heather L Clark
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States.,Department of Ophthalmology, University of California Irvine, Irvine, California, United States.,Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States
| | - Martin S Minns
- Department of Ophthalmology, University of California Irvine, Irvine, California, United States.,Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States
| | - Yan Sun
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States
| | - Tristan de Jesus
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States
| | - Mahmoud G Ghannoum
- Department of Dermatology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Eric Pearlman
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States.,Department of Ophthalmology, University of California Irvine, Irvine, California, United States.,Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States
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13
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Radke JB, Burrows JN, Goldberg DE, Sibley LD. Evaluation of Current and Emerging Antimalarial Medicines for Inhibition of Toxoplasma gondii Growth in Vitro. ACS Infect Dis 2018; 4:1264-1274. [PMID: 29998728 PMCID: PMC6093624 DOI: 10.1021/acsinfecdis.8b00113] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Toxoplasma gondii is a common zoonotic infection of humans, and estimates indicate that 1-2 billion people are chronically infected. Although largely asymptomatic, chronic infection poses risk of serious disease due to reactivation should immunity decline. Current therapies for toxoplasmosis only control acute infection caused by actively proliferating tachyzoites but do not eradicate the chronic tissue cyst stages. As well, there are considerable adverse side effects of the most commonly used therapy of combined sulfadiazine and pyrimethamine. Targeting the folate pathway is also an effective treatment for malaria, caused by the related parasites Plasmodium spp., suggesting common agents might be used to treat both infections. Here, we evaluated currently approved and newly emerging medicines for malaria to determine if such compounds might also prove useful for treating toxoplasmosis. Surprisingly, the majority of antimalarial compounds being used currently or in development for treatment of malaria were only modestly effective at inhibiting in vitro growth of T. gondii tachyzoites. These findings suggest that many essential processes in P. falciparum that are targeted by antimalarial compounds are either divergent or nonessential in T. gondii, thus limiting options for repurposing of current antimalarial medicines for toxoplasmosis.
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Affiliation(s)
- Joshua B. Radke
- Department of Molecular Microbiology, Washington University Sch. Med., 600 S. Euclid Ave., St Louis, MO 63110
| | - Jeremy N. Burrows
- Medicines for Malaria Venture, ICC, Route de Pré3Bois 20, 1215 Geneva, Switzerland
| | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University Sch. Med., 660 S. Euclid Ave., St Louis, MO 63110
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University Sch. Med., 600 S. Euclid Ave., St Louis, MO 63110
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14
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Si H, Xu C, Zhang J, Zhang X, Li B, Zhou X, Zhang J. Licochalcone A: An effective and low-toxicity compound against Toxoplasma gondii in vitro and in vivo. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:238-245. [PMID: 29684680 PMCID: PMC6039310 DOI: 10.1016/j.ijpddr.2018.02.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 02/23/2018] [Accepted: 02/27/2018] [Indexed: 11/25/2022]
Abstract
Toxoplasma gondii, an obligate intracellular protozoan, is the causative agent of toxoplasmosis, which can cause serious public health problems. The current drugs used to treat toxoplasmosis have many limitations. This study evaluated the anti-T. gondii activity and potential mechanism of Licochalcone A (Lico A) in vitro and in vivo. The safe concentration of Lico A in HFF cells was determined by MTT cell viability assays. The presence of T. gondii was assessed by qPCR and Giemsa staining. Azithromycin and sulfadiazine, commonly used effective treatments, served as drug controls. T. gondii ultrastructural alterations were observed by electron microscopy. The anti-T. gondii activity of Lico A was evaluated using an in vivo mouse infection model. In vitro, Lico A had no negative effect on host cell viability at concentrations below 9 μg/mL; however, it did inhibit T. gondii proliferation in a dose-dependent manner, with a 50% inhibitory concentration (IC50) of 0.848 μg/mL. Electron microscopy analyses indicated substantial structural and ultrastructural changes in tachyzoites after Lico A treatment. Nile Red staining assays demonstrated that Lico A caused lipid accumulation. Lico A treatment significantly increased the survival rate of BALB/c mice infected with T. gondii. Lico A achieved the same therapeutic effect as a commonly used clinical drugs (combination of sulfadiazine, pyrimethamine and folinic acid). In conclusion, Lico A has strong anti-T. gondii activity in vitro and in vivo and might be developed into a new anti-T. gondii drug. Moreover, Lico A may exert these effects by interfering with lipid metabolism in the parasite.
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Affiliation(s)
- Hongfei Si
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang, China; Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, Gansu, China
| | - Chunyan Xu
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Jili Zhang
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, Gansu, China
| | - Xukun Zhang
- College of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110000, China
| | - Bing Li
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, Gansu, China
| | - Xuzheng Zhou
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, Gansu, China
| | - Jiyu Zhang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang, China; Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, Gansu, China.
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15
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da Silva LLR, Portes JDA, de Araújo MH, Silva JLS, Rennó MN, Netto CD, da Silva AJM, Costa PRR, De Souza W, Seabra SH, DaMatta RA. Further evidence that naphthoquinone inhibits Toxoplasma gondii growth in vitro. Parasitol Int 2015; 64:622-31. [PMID: 26335616 DOI: 10.1016/j.parint.2015.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 08/25/2015] [Accepted: 08/28/2015] [Indexed: 11/30/2022]
Abstract
Toxoplasmosis is a widely disseminated disease caused by Toxoplasma gondii, an intracellular protozoan parasite. Standard treatment causes many side effects, such as depletion of bone marrow cells, skin rashes and gastrointestinal implications. Therefore, it is necessary to find chemotherapeutic alternatives for the treatment of this disease. It was shown that a naphthoquinone derivative compound is active against T. gondii, RH strain, with an IC50 around 2.5 μM. Here, three different naphthoquinone derivative compounds with activity against leukemia cells and breast carcinoma cell were tested against T. gondii (RH strain) infected LLC-MK2 cell line. All the compounds were able to inhibit parasite growth in vitro, but one of them showed an IC50 activity below 1 μM after 48 h of treatment. The compounds showed low toxicity to the host cell. In addition, these compounds were able to induce tachyzoite-bradyzoite conversion confirmed by morphological changes, Dolichus biflorus lectin cyst wall labeling and characterization of amylopectin granules in the parasites by electron microscopy analysis using the Thierry technique. Furthermore, the compounds induced alterations on the ultrastructure of the parasite. Taken together, our results point to the naphthoquinone derivative (LQB 151) as a potential compound for the development of new drugs for the treatment of toxoplasmosis.
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Affiliation(s)
- Luciana Lemos Rangel da Silva
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Juliana de Araujo Portes
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste, Campo Grande, Rio de Janeiro, RJ, 23070-200, Brazil
| | - Marlon Heggdorne de Araújo
- Laboratório de Produtos Bioativos, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27930-560, Brazil
| | - Jéssica Lays Sant'ana Silva
- Laboratório de Química, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27930-560, Brazil
| | - Magdalena Nascimento Rennó
- Laboratório de Modelagem Molecular e Pesquisa em Ciências Farmacêuticas, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27910-970, Brazil
| | - Chaquip Daher Netto
- Laboratório de Química, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27930-560, Brazil
| | - Alcides José Monteiro da Silva
- Laboratório de Química Bioorgânica, Instituto de Pesquisas de Produtos Naturais, Centro de Ciências da Saúde, Bloco H, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Paulo Roberto Ribeiro Costa
- Laboratório de Química Bioorgânica, Instituto de Pesquisas de Produtos Naturais, Centro de Ciências da Saúde, Bloco H, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Wanderley De Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21491-590, Brazil; Instituto Nacional de Metrologia, Qualidade Industrial e Tecnologia-Inmetro, Duque de Caxias, RJ, 20261-232, Brazil
| | - Sergio Henrique Seabra
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste, Campo Grande, Rio de Janeiro, RJ, 23070-200, Brazil
| | - Renato Augusto DaMatta
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil.
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16
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Cohen A, Suzanne P, Lancelot JC, Verhaeghe P, Lesnard A, Basmaciyan L, Hutter S, Laget M, Dumètre A, Paloque L, Deharo E, Crozet MD, Rathelot P, Dallemagne P, Lorthiois A, Sibley CH, Vanelle P, Valentin A, Mazier D, Rault S, Azas N. Discovery of new thienopyrimidinone derivatives displaying antimalarial properties toward both erythrocytic and hepatic stages of Plasmodium. Eur J Med Chem 2015; 95:16-28. [DOI: 10.1016/j.ejmech.2015.03.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 11/24/2022]
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17
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Pantothenic acid biosynthesis in the parasite Toxoplasma gondii: a target for chemotherapy. Antimicrob Agents Chemother 2014; 58:6345-53. [PMID: 25049241 DOI: 10.1128/aac.02640-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is a major food pathogen and neglected parasitic infection that causes eye disease, birth defects, and fetal abortion and plays a role as an opportunistic infection in AIDS. In this study, we investigated pantothenic acid (vitamin B5) biosynthesis in T. gondii. Genes encoding the full repertoire of enzymes for pantothenate synthesis and subsequent metabolism to coenzyme A were identified and are expressed in T. gondii. A panel of inhibitors developed to target Mycobacterium tuberculosis pantothenate synthetase were tested and found to exhibit a range of values for inhibition of T. gondii growth. Two inhibitors exhibited lower effective concentrations than the currently used toxoplasmosis drug pyrimethamine. The inhibition was specific for the pantothenate pathway, as the effect of the pantothenate synthetase inhibitors was abrogated by supplementation with pantothenate. Hence, T. gondii encodes and expresses the enzymes for pantothenate synthesis, and this pathway is essential for parasite growth. These promising findings increase our understanding of growth and metabolism in this important parasite and highlight pantothenate synthetase as a new drug target.
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18
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Structural analysis of atovaquone-inhibited cytochrome bc1 complex reveals the molecular basis of antimalarial drug action. Nat Commun 2014; 5:4029. [DOI: 10.1038/ncomms5029] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 05/02/2014] [Indexed: 11/08/2022] Open
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19
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Suttorp-Schulten MS, Jager MJ, Kijlstra A. Recent developments in the treatment of posterior uveitis. Ocul Immunol Inflamm 2012; 4:207-17. [PMID: 22827460 DOI: 10.3109/09273949609079654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Uveitis is an intraocular inflammation that can be caused by infection, autoimmune disease, trauma or malignancy. It is a serious cause of visual handicap and therapy is targeted at: removal of possible infectious agents, the immunological processes that lead to or sustain the inflammation and finally to prevent or treat the destructive effects of the inflammation on the delicate ocular structures. In this review the latest developments concerning the treatment of posterior uveitis are illuminated, e. g., new approaches concerning the treatment of infectious uveitis including the therapy of herpes virus (VZV, HSV and CMV), bacterial and toxoplasma infections of the eye. Several new ways to influence the immune response and inflammation are described including the use of interferons, modulation of cytokines, soft steroids, other new immunosuppressive drugs and treatment of autoimmune uveitis by oral tolerization. An overview is given to illustrate new ways to administer drugs into eyes, such as intravitreal devices. Finally new developments in the field of the treatment of the various complications of uveitis (cystoid macular edema) are described.
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20
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Ferreira RA, de Oliveira AB, Gualberto SA, Miguel Del Corral JM, Fujiwara RT, Gazzinelli Guimarães PH, de Almeida Vitor RW. New naphthoquinones and an alkaloid with in vitro activity against Toxoplasma gondii RH and EGS strains. Exp Parasitol 2012; 132:450-7. [PMID: 23000485 DOI: 10.1016/j.exppara.2012.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 08/28/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
Abstract
The efficacy of three amino-terpenyl naphthoquinones and the alkaloid liriodenine were examined against tachyzoites and tissues cysts of the RH and EGS strains, respectively. Monolayers of 2C4 fibroblasts infected with tachyzoites of the RH strain were incubated with different concentrations of the compounds for 48 h. Specifically, 7-(4-methyl-3-pentenyl)-2-pyrrolidine-[1,4]-naphthoquinone (QUI-5), 6-(4-methyl-3-pentenyl)-2-pyrrolidine-[1,4]-naphthoquinone (QUI-6), 6-(4-methylpentyl)-2-pyrrolidine-[1,4]-naphthoquinone (QUI-11), and 8 h-benzo[g]-1,3-benzodioxolo[6,5,4-de]quinolin-8-one,9Cl-1,2-methylene dioxiaporfina (liriodenine) inhibited intracellular replication of T. gondii. The IC(50) values obtained for compounds QUI-5 and QUI-6 were 69.35 and 172.81 μM (i.e., 21.4 and 53.4 μg/mL), respectively. The naphthoquinone QUI-11 and liriodenine significantly inhibited intracellular replication of T. gondii. The IC(50) values obtained with these experiments were 0.32 and 0.07 μM (i.e., 0.1 and 0.02 μg/mL), respectively. Compounds QUI-5, QUI-6, QUI-11 and liriodenine demonstrated lower toxicity for 2C4 fibroblasts compared to atovaquone. In addition, cysts isolated from the brains of mice chronically infected with the EGS strain were exposed to the compounds. Infectivity of the cysts after incubation with the compounds was assessed by infection of mice. The data obtained showed that in vitro incubation with QUI-6, QUI-11 and liriodenine inhibited the infectivity of the bradyzoites. This activity was time- and concentration-dependent.
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Affiliation(s)
- Ronize Andréia Ferreira
- Laboratório de Microscopia, Instituto de Ciências Agrárias, Faculdade de Estudos Administrativos, FEAD, Brazil
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Jin C, Jung SY, Kim SY, Song HO, Park H. Simple and efficient model systems of screening anti-Toxoplasmadrugsin vitro. Expert Opin Drug Discov 2012; 7:195-205. [DOI: 10.1517/17460441.2012.660479] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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22
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Alvarado-Esquivel C, Niewiadomski A, Schweickert B, Liesenfeld O. Antiparasitic treatment suppresses production and avidity of Toxoplasma gondii-specific antibodies in a murine model of acute infection*. Eur J Microbiol Immunol (Bp) 2011; 1:249-55. [PMID: 24516731 DOI: 10.1556/eujmi.1.2011.3.9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 07/14/2011] [Indexed: 01/04/2023] Open
Abstract
Infection with Toxoplasma gondii during pregnancy may result in congenital transmission of the parasite. Infection is commonly diagnosed using serological tests for IgG, IgM and IgA antibodies. Avidity of IgG antibodies is used to exclude acute infection. Few studies have investigated the impact of antiparasitic treatment on the production of anti-T. gondii antibody and the avidity of IgG antibodies. We therefore investigated the production of IgG, IgM, and IgA antibodies and IgG avidity in a murine model of acute infection with 10 cysts of T. gondii. All antibody classes increased following infection. Treatment of mice with pyrimethamine/sulfadiazine but not with spiramycin or azithromycin at dosages equivalent to those used in patients resulted in a significant decrease in the concentration of T. gondii-specific IgG and IgM antibodies postinfection. IgG and IgM antibody decreases were paralleled by a significant reduction in cyst numbers in brains of mice treated with pyrimethamine/sulfadiazine but not with other drugs. In contrast, treatment with atovaquone did significantly reduce the concentrations of IgM antibodies and resulted in reduced IgG avidity indices. T. gondii-specific DNA was not detected in blood between days 1 and 3. In conclusion, antiparasitic treatment with pyrimethamine/sulfadiazine and atovaquone appears to impact the generation of antibody responses against T. gondii. Future studies will have to determine the specific impact of antiparasitic treatment on antibody responses and the consequences for the management of patients infected with T. gondii.
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Affiliation(s)
- C Alvarado-Esquivel
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
| | - A Niewiadomski
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
| | - B Schweickert
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
| | - O Liesenfeld
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
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Cyclodextrin/poly(anhydride) nanoparticles as drug carriers for the oral delivery of atovaquone. Biomed Microdevices 2011; 13:1015-25. [DOI: 10.1007/s10544-011-9571-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Abstract
This article is an attempt to identify the most significant highlights of Toxoplasma research over the last 25 years. It has been a period of enormous progress and the top 25 most significant advances, in the view of this author, are described. These range from the bench to the bedside and represent a tremendous body of work from countless investigators. And, having laid out so much that has been discovered, it is impossible not to also reflect on the challenges that lie ahead. These, too, are briefly discussed. Finally, while every effort has been made to view the field as a whole, the molecular biology background of the author almost certainly will have skewed the relative importance attached to past and future advances. Despite this, it is hoped that the reader will agree with, or at least not disagree too strongly with, most of the choices presented here.
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Affiliation(s)
- John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, CA 94305-5124, USA.
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25
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Gurule S, Goswami D, Khuroo AH, Monif T. LC-APCI mass spectrometric method development and validation for the determination of atovaquone in human plasma. Biomed Chromatogr 2010; 24:497-505. [PMID: 19711297 DOI: 10.1002/bmc.1317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A newly developed LC-APCI mass spectrometric method is described for human plasma determination of atovaquone using lapachol internal standard. A single-step protein precipitation technique for plasma extraction of atovaquone achieving mean recovery of 94.17% (CV 8%) without compromising sensitivity (limit of quantitation 50.3 ng/mL) or linearity (50.3 ng/mL-23924.6 ng/mL) is delineated in this paper. Heated nebulizer in negative multiple reaction monitoring mode was employed with transitions m/z 365.2 --> m/z 337.1 and m/z 240.9 --> m/z 185.7 for atovaquone and lapachol respectively in this liquid chromatographic-tandem mass spectrometric method. Excellent chromatographic separation on a Synergi 4 micro Polar-RP 80A (150 x 2.0 mm) column, using 100 microL of plasma extraction volume along with 10 microL of injection load, completing analysis run-time within 2.5 min, highlights this simple yet unique bioanalytical method. The developed method can be successfully applied to pharmacokinetic studies on atovaquone suspension administered in healthy volunteers or HIV-infected patients. Moreover full method validation results not published before are presented and discussed in detail for the first time in this article.
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Affiliation(s)
- Sanjay Gurule
- Department of Clinical Pharmacology and Pharmacokinetics, Ranbaxy Laboratories Ltd, Gurgaon, Haryana, India
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Shubar HM, Lachenmaier S, Heimesaat MM, Lohman U, Mauludin R, Mueller RH, Fitzner R, Borner K, Liesenfeld O. SDS-coated atovaquone nanosuspensions show improved therapeutic efficacy against experimental acquired and reactivated toxoplasmosis by improving passage of gastrointestinal and blood-brain barriers. J Drug Target 2010; 19:114-24. [PMID: 20367080 DOI: 10.3109/10611861003733995] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Toxoplasmic encephalitis (TE) is the most common clinical manifestation of reactivated infection with Toxoplasma gondii in immunocompromised patients that is lethal if untreated. The combination of pyrimethamine plus sulfadiazine or clindamycin is the standard therapy for the treatment of TE, but these combinations are associated with hematologic toxicity and/or life-threatening allergic reactions. Therefore, alternative treatment options are needed. Atovaquone is safe and highly effective against T. gondii in vitro, but the oral micronized solution shows poor bioavailability. We synthesized atovaquone nanosuspensions (ANSs) coated with poloxamer 188 (P188) and sodium dodecyl sulfate (SDS) to improve oral bioavailability and passage through the blood-brain barrier (BBB). Coating of ANSs with SDS resulted in enhanced oral bioavailability and enhanced brain uptake of atovaquone compared to Wellvone(®) in murine models of acute and reactivated toxoplasmosis as measured by high performance liquid chromatography (HPLC). Parasite loads and inflammatory changes in brains of mice treated with SDS-coated ANS were significantly reduced compared to untreated controls and to Wellvone(®)-treated mice. In conclusion, nanosuspensions coated with SDS may ultimately lead to improvements in the treatment of TE and other cerebral diseases.
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Affiliation(s)
- Hend M Shubar
- Institute of Microbiology and Hygiene, Campus Benjamin Franklin, Charité-University Medicine Berlin, Berlin, Germany
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Kabri Y, Azas N, Dumètre A, Hutter S, Laget M, Verhaeghe P, Gellis A, Vanelle P. Original quinazoline derivatives displaying antiplasmodial properties. Eur J Med Chem 2010; 45:616-22. [PMID: 19926173 DOI: 10.1016/j.ejmech.2009.11.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/23/2009] [Accepted: 11/02/2009] [Indexed: 11/30/2022]
Affiliation(s)
- Youssef Kabri
- Laboratoire de Pharmacochimie Radicalaire, Faculté de Pharmacie, Universités d'Aix-Marseille I, II et III - UMR CNRS 6264, Laboratoire Chimie Provence, 27 Boulevard Jean Moulin, 13385 Marseille cedex 05, France
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28
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Verhaeghe P, Azas N, Hutter S, Castera-Ducros C, Laget M, Dumètre A, Gasquet M, Reboul JP, Rault S, Rathelot P, Vanelle P. Synthesis and in vitro antiplasmodial evaluation of 4-anilino-2-trichloromethylquinazolines. Bioorg Med Chem 2009; 17:4313-22. [DOI: 10.1016/j.bmc.2009.05.022] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/05/2009] [Accepted: 05/11/2009] [Indexed: 11/24/2022]
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29
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Shubar HM, Dunay IR, Lachenmaier S, Dathe M, Bushrab FN, Mauludin R, Müller RH, Fitzner R, Borner K, Liesenfeld O. The role of apolipoprotein E in uptake of atovaquone into the brain in murine acute and reactivated toxoplasmosis. J Drug Target 2009; 17:257-67. [DOI: 10.1080/10611860902718680] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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30
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Dubey JP, Crutchley C. Toxoplasmosis in wallabies (Macropus rufogriseus and Macropus eugenii): blindness, treatment with atovaquone, and isolation of Toxoplasma gondii. J Parasitol 2008; 94:929-33. [PMID: 18576797 DOI: 10.1645/ge-1448.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Accepted: 11/28/2007] [Indexed: 11/10/2022] Open
Abstract
Australasian marsupials, especially wallabies, are highly susceptible to clinical toxoplasmosis. This paper describes the use of atovaquone for effective treatment of toxoplasmosis in 4 Bennett's wallabies (Macropus rufogriseus), along with the serology, isolation of Toxoplasma gondii, and genotyping of 3 T. gondii isolates from 5 captive wallabies. This is the first report of success in treating acute toxoplasmosis in wallabies, the first report of serology followed over a significant period of time, and the first report of isolation and genetic typing of T. gondii from wallabies in the United States.
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Affiliation(s)
- J P Dubey
- United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Beltsville, Maryland 20705-2350, USA.
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31
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Miró JM. Prevención de las infecciones oportunistas en pacientes adultos y adolescentes infectados por el VIH en el año 2008. Enferm Infecc Microbiol Clin 2008; 26:437-64. [DOI: 10.1157/13125642] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Temporal and spatial distribution of Toxoplasma gondii differentiation into Bradyzoites and tissue cyst formation in vivo. Infect Immun 2008; 76:3491-501. [PMID: 18505811 DOI: 10.1128/iai.00254-08] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During Toxoplasma gondii infection, a fraction of the multiplying parasites, the tachyzoites, converts into bradyzoites, a dormant stage, which form tissue cysts localized mainly in brain, heart, and skeletal muscles that persist for several years after infection. At this stage the parasite is protected from the immune system, and it is believed to be inaccessible to drugs. While the long persistence of tissue cysts does not represent a medical problem for healthy individuals, this condition represents a major risk for patients with a compromised immune system, who can develop recrudescent life-threatening T. gondii infections. We have investigated for the first time the dynamics and the kinetics of tachyzoite-to-bradyzoite interconversion and cyst formation in vivo by using stage-specific bioluminescent parasites in a mouse model. Our findings provide a new framework for understanding the process of bradyzoite differentiation in vivo. We have also demonstrated that complex molecules such as d-luciferin have access to tissue cysts and are metabolically processed, thus providing a rationale for developing drugs that attack the parasite at this developmental stage.
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33
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Kessl JJ, Meshnick SR, Trumpower BL. Modeling the molecular basis of atovaquone resistance in parasites and pathogenic fungi. Trends Parasitol 2007; 23:494-501. [PMID: 17826334 DOI: 10.1016/j.pt.2007.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 06/27/2007] [Accepted: 08/23/2007] [Indexed: 10/22/2022]
Abstract
Atovaquone is a substituted hydroxynaphthoquinone that is used therapeutically for treating Plasmodium falciparum malaria, Pneumocystis jirovecii pneumonia and Toxoplasma gondii toxoplasmosis. It is thought to act on these organisms by inhibiting parasite and fungal respiration by binding to the cytochrome bc1 complex. The recent, growing failure of atovaquone treatment and increased mortality of patients with malaria or Pneumocystis pneumonia has been linked to the appearance of mutations in the cytochrome b gene. To better understand the molecular basis of drug resistance, we have developed the yeast and bovine bc1 complexes as surrogates to model the molecular interaction of atovaquone with human and resistant pathogen enzymes.
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Affiliation(s)
- Jacques J Kessl
- Center for Retrovirus Research, College of Pharmacy, Ohio State University, Columbus, OH 43210, USA
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34
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Molecular surveillance of mutations in the cytochrome b gene of Plasmodium falciparum in Gabon and Ethiopia. Malar J 2006; 5:112. [PMID: 17118179 PMCID: PMC1679811 DOI: 10.1186/1475-2875-5-112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Accepted: 11/21/2006] [Indexed: 11/10/2022] Open
Abstract
Background Atovaquone is part of the antimalarial drug combination atovaquone-proguanil (Malarone®) and inhibits the cytochrome bc1 complex of the electron transport chain in Plasmodium spp. Molecular modelling showed that amino acid mutations are clustered around a putative atovaquone-binding site resulting in a reduced binding affinity of atovaquone for plasmodial cytochrome b, thus resulting in drug resistance. Methods The prevalence of cytochrome b point mutations possibly conferring atovaquone resistance in Plasmodium falciparum isolates in atovaquone treatment-naïve patient cohorts from Lambaréné, Gabon and from South Western Ethiopia was assessed. Results Four/40 (10%) mutant types (four different single polymorphisms, one leading to an amino acid change from M to I in a single case) in Gabonese isolates, but all 141/141 isolates were wild type in Ethiopia were found. Conclusion In the absence of drug pressure, spontaneous and possibly resistance-conferring mutations are rare.
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35
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Kosobucki BR, Freeman WR. Retinal Disease in HIV-infected Patients. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50098-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Benson CA, Kaplan JE, Masur H, Pau A, Holmes KK. Treating Opportunistic Infections among HIV-Infected Adults and Adolescents: Recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association/Infectious Diseases Society of America. Clin Infect Dis 2005. [DOI: 10.1086/427906] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Dunay IR, Heimesaat MM, Bushrab FN, Müller RH, Stocker H, Arasteh K, Kurowski M, Fitzner R, Borner K, Liesenfeld O. Atovaquone maintenance therapy prevents reactivation of toxoplasmic encephalitis in a murine model of reactivated toxoplasmosis. Antimicrob Agents Chemother 2005; 48:4848-54. [PMID: 15561866 PMCID: PMC529229 DOI: 10.1128/aac.48.12.4848-4854.2004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acute therapy with pyrimethamine plus sulfadiazine is the treatment of choice for reactivated toxoplasmic encephalitis (TE). Acute therapy is followed by lifelong maintenance therapy (secondary prophylaxis) with the same drugs at lower dosages. The use of pyrimethamine plus sulfadiazine is hampered by severe side effects including allergic reactions and hematotoxicity. Alternative treatment regimens with pyrimethamine plus clindamycin or other antiparasitic drugs are less efficacious. Atovaquone nanosuspensions show excellent therapeutic effects for "acute" intravenous (i.v.) treatment of reactivated TE in a murine model. In the present study, the therapeutic efficacy of atovaquone for oral "maintenance" therapy was investigated. Mice with a targeted mutation in the interferon regulatory factor 8 gene were latently infected with Toxoplasma gondii, developed reactivated TE, and received acute i.v. therapy with atovaquone nanosuspensions. Mice were then treated orally with atovaquone suspension or other antiparasitic drugs to prevent relapse of TE. Maintenance therapy with atovaquone at daily doses of 50 or 100 mg/kg (body weight) protected mice against reactivated TE and death. This maintenance treatment was superior to standard therapy with pyrimethamine plus sulfadiazine. The latter combination was superior to the combination of pyrimethamine plus clindamycin. Inflammatory changes in the brain parenchyma and meninges, as well as parasite numbers, in the brains of mice confirmed the therapeutic efficacy of atovaquone for maintenance therapy. Atovaquone was detectable in sera, brains, livers, and lungs of infected mice by high-performance liquid chromatography and/or mass spectrometry. In conclusion, atovaquone appears to be superior to the standard maintenance therapy regimens in a murine model of reactivated TE. The therapeutic efficacy of atovaquone for maintenance therapy against TE should be further investigated in clinical trials.
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Affiliation(s)
- Ildiko R Dunay
- Department of Medical Microbiology and Immunology of Infection, Institute for Infection Medicine, Campus Benjamin Franklin, Charité Medical School, Berlin, Germany
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38
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Berenguer J, Laguna F, López-Aldeguer J, Moreno S, Arribas JR, Arrizabalaga J, Baraia J, Casado JL, Cosín J, Polo R, González-García J, Iribarren JA, Kindelán JM, López-Bernaldo de Quirós JC, López-Vélez R, Lorenzo JF, Lozano F, Mallolas J, Miró JM, Pulido F, Ribera E. Prevention of opportunistic infections in adult and adolescent patients with HIV infection. GESIDA/National AIDS Plan guidelines, 2004 [correction]. Enferm Infecc Microbiol Clin 2004; 22:160-76. [PMID: 14987537 DOI: 10.1016/s0213-005x(04)73057-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To provide an update of guidelines from the Spanish AIDS Study Group (GESIDA) and the National AIDS Plan (PNS) committee on the prevention of opportunistic infections in adult and adolescent HIV-infected patients. METHODS These consensus recommendations have been produced by a group of experts from GESIDA and/or the PNS after reviewing the earlier document and the scientific advances in this field in the last years. The system used by the Infectious Diseases Society of America and the United States Public Health Service has been used to classify the strength and quality of the data. RESULTS This document provides a detailed review of the measures for the prevention of infections caused by viruses, bacteria, fungi and parasites in the context of HIV infection. Recommendations are given for preventing exposure and for primary and secondary prophylaxis for each group of pathogens. In addition, criteria are established for the withdrawal of prophylaxis in patients who respond well to highly active antiretroviral therapy (HAART). CONCLUSIONS HAART is the best strategy for the prevention of opportunistic infections in HIV-positive patients. Nevertheless, prophylaxis is still necessary in countries with limited economic resources, in highly immunodepressed patients until HAART achieves beneficial effects, in patients who refuse to take or who cannot take HAART, in those in whom HAART is not effective, and in the small group of infected patients with inadequate recovery of CD4+ T lymphocyte counts despite good inhibition of HIV replication.
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Affiliation(s)
- Juan Berenguer
- Unidad de Enfermedades Infecciosas, Hospital General Gregorio Marañón, Madrid, Spain.
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39
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Ferreira MS, Borges AS. Some aspects of protozoan infections in immunocompromised patients- a review. Mem Inst Oswaldo Cruz 2002; 97:443-57. [PMID: 12118272 DOI: 10.1590/s0074-02762002000400001] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Protozoa are among the most important pathogens that can cause infections in immunocompromised hosts. These microorganisms particularly infect individuals with impaired cellular immunity, such as those with hematological neoplasias, renal or heart transplant patients, patients using high doses of corticosteroids, and patients with acquired immunodeficiency syndrome. The protozoa that most frequently cause disease in immunocompromised patients are Toxoplasma gondii, Trypanosoma cruzi, different Leishmania species, and Cryptosporidium parvum; the first two species cause severe acute meningoencephalitis and acute myocarditis, Leishmania sp. causes mucocutaneous or visceral disease, and Cryptosporidium can lead to chronic diarrhea with hepatobiliary involvement. Various serological, parasitological, histological and molecular methods for the diagnosis of these infections are currently available and early institution of specific therapy for each of these organisms is a basic measure to reduce the morbidity and mortality associated with these infections.
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Affiliation(s)
- Marcelo Simão Ferreira
- Faculdade de Medicina, Universidade Federal de Uberlândia, Uberlândia, MG, 38400-027, Brasil.
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40
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Chirgwin K, Hafner R, Leport C, Remington J, Andersen J, Bosler EM, Roque C, Rajicic N, McAuliffe V, Morlat P, Jayaweera DT, Vilde JL, Luft BJ. Randomized phase II trial of atovaquone with pyrimethamine or sulfadiazine for treatment of toxoplasmic encephalitis in patients with acquired immunodeficiency syndrome: ACTG 237/ANRS 039 Study. AIDS Clinical Trials Group 237/Agence Nationale de Recherche sur le SIDA, Essai 039. Clin Infect Dis 2002; 34:1243-50. [PMID: 11941551 DOI: 10.1086/339551] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
In this international, noncomparative, randomized phase II trial, we evaluated the effectiveness and tolerance of atovaquone suspension (1500 mg orally twice daily) plus either pyrimethamine (75 mg per day after a 200-mg loading dose) or sulfadiazine (1500 mg 4 times daily) as treatment for acute disease (for 6 weeks) and as maintenance therapy (for 42 weeks) for toxoplasmic encephalitis (TE) in patients infected with human immunodeficiency virus. Twenty-one (75%) of 28 patients receiving pyrimethamine (95% lower confidence interval [CI], 58%) and 9 (82%) of 11 patients receiving sulfadiazine (95% lower CI, 53%) responded to treatment for acute disease. Of 20 patients in the maintenance phase, only 1 experienced relapse. Eleven (28%) of 40 eligible patients discontinued treatment as a result of adverse events, 9 because of nausea and vomiting or intolerance of the taste of the atovaquone suspension. Although gastrointestinal side effects were frequent, atovaquone-containing regimens are otherwise well tolerated and safe and may be useful for patients intolerant of standard regimens for toxoplasmic encephalitis.
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Affiliation(s)
- Keith Chirgwin
- Department of Medicine, State University of New York at Brooklyn, NY, USA.
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41
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Affiliation(s)
- Aaron L Baggish
- University of Connecticut School of Medicine, Farmington, Connecticut, USA
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42
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Nare B, Allocco JJ, Liberator PA, Donald RGK. Evaluation of a cyclic GMP-dependent protein kinase inhibitor in treatment of murine toxoplasmosis: gamma interferon is required for efficacy. Antimicrob Agents Chemother 2002; 46:300-7. [PMID: 11796334 PMCID: PMC127074 DOI: 10.1128/aac.46.2.300-307.2002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The trisubstituted pyrrole 4-[2-(4-fluorophenyl)-5-(1-methylpiperidine-4-yl)-1H-pyrrol-3-yl]pyridine (compound 1) is a potent inhibitor of cyclic GMP-dependent protein kinases from Apicomplexan protozoa and displays cytostatic activity against Toxoplasma gondii in vitro. Compound 1 has now been evaluated against T. gondii infections in the mouse and appeared to protect the animals when given intraperitoneally at 50 mg/kg twice daily for 10 days. However, samples from brain, spleen, and lung taken from infected treated mice revealed the presence of parasites after cessation of administration of compound 1, indicating that a transient asymptomatic parasite recrudescence occurs in all survivors. The ability of mice to control Toxoplasma infection after compound 1 treatment has been terminated suggested that the mouse immune system plays a synergistic role with chemotherapy in controlling the infection. To explore this possibility, gamma interferon (IFN-gamma)-knockout mice were infected with parasites and treated with compound 1, and survival was compared to that of normal mice. IFN-gamma-knockout mice were protected against T. gondii throughout the treatment phase but died during the posttreatment phase in which peak recrudescence was observed in treated immunocompetent mice. These data suggest that an IFN-gamma-dependent immune response was essential for controlling and resolving parasite recrudescence in mice treated with compound 1. In addition, when compound 1-cured immunocompetent mice were rechallenged with a lethal dose of T. gondii, all survived (n = 32). It appears that the cytostatic nature of compound 1 provides an "immunization" phase during chemotherapy which allows the mice to survive the recrudescence and any subsequent challenge with a lethal dose of T. gondii.
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Affiliation(s)
- Bakela Nare
- Department of Human and Animal Infectious Disease Research, Merck Research Laboratories, Merck and Co., Inc., Rahway, New Jersey 07076, USA.
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43
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Podzamczer D, Ramón Arribas J, Mallolas J, María Peña J, Pulido F. [Treatment of opportunistic infections among adult and adolescent patients infected with the human immunodeficiency virus in the era of highly active anti-retroviral therapy]. Enferm Infecc Microbiol Clin 2001; 19:376-92. [PMID: 11602139 DOI: 10.1016/s0213-005x(01)72670-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D Podzamczer
- Ciutat Sanitària i Universitària de Bellvitge, Barcelona, Spain.
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44
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Purdy BD. Management and Prevention of Opportunistic Infections in the HIV-Infected Patient. J Pharm Pract 2000. [DOI: 10.1106/jdyc-jyvc-xjaa-lj1f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
With the introduction of potent antiretroviral therapy, the incidence of opportunistic infections (OIs) as well as death has dramatically decreased since 1996. Opportunistic infections are seen mainly in three groups: (1) newly diagnosed patients not receiving antiretroviral therapy and presenting with an OI, (2) patients nonadherent to antiretroviral and OI treatment regimens or (3) patients whose antiretroviral therapy has failed. This article will review the most common opportunistic infections (OIs) seen in the HIV-infected individual and their treatment. The current guidelines for the prophylaxis against these OIs will also be discussed.
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Affiliation(s)
- Bonnie D. Purdy
- Albany Medical Center, Mail-code 85, 43 New Scotland Avenue, Albany, New York 12208,
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45
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Abstract
Atovaquone is a broad-spectrum antiparasitic agent active against malaria, Pneumocystis carinii pneumonia, toxoplasmosis and babesiosis. When used as a single agent, resistance to atovaquone arose rapidly in falciparum malaria, requiring the development of a new antimalarial drug combination of atovaquone and proguanil. Recent laboratory investigations have provided insights into the mode of atovaquone action, and identified the molecular basis for the resistance development. Mutations within a catalytic domain of the cytochrome bc(1)complex present within the parasite mitochondrial inner membrane were shown to be responsible for atovaquone resistance. Here, we review these studies and propose a mechanism by which atovaquone resistance may arise quickly in malaria parasites. Copyright 2000 Harcourt Publishers Ltd.
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Affiliation(s)
- Akhil B. Vaidya
- Department of Microbiology and Immunology, MCP Hahnemann University, Philadelphia, USA
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46
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Djurković-Djaković O, Nikolić T, Robert-Gangneux F, Bobić B, Nikolić A. Synergistic effect of clindamycin and atovaquone in acute murine toxoplasmosis. Antimicrob Agents Chemother 1999; 43:2240-4. [PMID: 10471572 PMCID: PMC89454 DOI: 10.1128/aac.43.9.2240] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of clindamycin (CLI) combined with autovaquone (ATO) was examined in a murine model of acute toxoplasmosis. Swiss Webster mice intraperitoneally infected with 10(2) or 10(4) tachyzoites of the RH strain of Toxoplasma gondii were perorally treated with either drug alone (for ATO, 5, 25, 50, or 100 mg/kg of body weight/day; for CLI, 25, 50, or 400 mg/kg/day) or both combined (for ATO plus CLI, respectively, 5 plus 25, 25 plus 25, 25 plus 50, 50 plus 50, or 100 plus 400 mg/kg/day) starting with day 1 for 14 days. Survival was monitored during 7 weeks. Residual infection was assessed by a bioassay of representative 4-week survivors and by parasite DNA detection by PCR for representative 7-week survivors. An effect of treatment was shown in all treatment groups compared to untreated control mice (P = 0.0000). Among mice infected with 10(2) parasites, ATO and CLI at any dose combination protected significantly more animals than ATO alone (P = 0.0000), but compared to CLI alone, given its good effect, the combined drugs were no more effective (P > 0.05). For mice infected with 10(4) parasites, the drugs combined at the lowest and highest doses (5 plus 25 and 100 plus 400 mg/kg/day) were, similarly, more effective than ATO alone (P = 0.035 and 0.000, respectively) but not than CLI alone (P > 0. 05). However, treatment with ATO plus CLI at 25 plus 25, 25 plus 50, and 50 plus 50 mg/kg/day protected 20, 33, and 78% of mice, respectively, compared to virtually no survivals among those treated with either drug alone (P < 0.0005), thus demonstrating a significant synergistic effect of ATO and CLI against T. gondii. Furthermore, the dose of ATO at a given dose of CLI was shown to be critical to the effect. Moreover, the absence of residual infection in some survivors shows the potential of this drug combination to eliminate the parasite.
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Affiliation(s)
- O Djurković-Djaković
- Toxoplasmosis Research Laboratory, Institute for Medical Research, Belgrade, Yugoslavia.
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47
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Srivastava IK, Morrisey JM, Darrouzet E, Daldal F, Vaidya AB. Resistance mutations reveal the atovaquone-binding domain of cytochrome b in malaria parasites. Mol Microbiol 1999; 33:704-11. [PMID: 10447880 DOI: 10.1046/j.1365-2958.1999.01515.x] [Citation(s) in RCA: 207] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Atovaquone represents a class of antimicrobial agents with a broad-spectrum activity against various parasitic infections, including malaria, toxoplasmosis and Pneumocystis pneumonia. In malaria parasites, atovaquone inhibits mitochondrial electron transport at the level of the cytochrome bc1 complex and collapses mitochondrial membrane potential. In addition, this drug is unique in being selectively toxic to parasite mitochondria without affecting the host mitochondrial functions. A better understanding of the structural basis for the selective toxicity of atovaquone could help in designing drugs against infections caused by mitochondria-containing parasites. To that end, we derived nine independent atovaquone-resistant malaria parasite lines by suboptimal treatment of mice infected with Plasmodium yoelii; these mutants exhibited resistance to atovaquone-mediated collapse of mitochondrial membrane potential as well as inhibition of electron transport. The mutants were also resistant to the synergistic effects of atovaquone/ proguanil combination. Sequencing of the mitochondrially encoded cytochrome b gene placed these mutants into four categories, three with single amino acid changes and one with two adjacent amino acid changes. Of the 12 nucleotide changes seen in the nine independently derived mutants 11 replaced A:T basepairs with G:C basepairs, possibly because of reactive oxygen species resulting from atovaquone treatment. Visualization of the resistance-conferring amino acid positions on the recently solved crystal structure of the vertebrate cytochrome bc1 complex revealed a discrete cavity in which subtle variations in hydrophobicity and volume of the amino acid side-chains may determine atovaquone-binding affinity, and thereby selective toxicity. These structural insights may prove useful in designing agents that selectively affect cytochrome bc1 functions in a wide range of eukaryotic pathogens.
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Affiliation(s)
- I K Srivastava
- Department of Microbiology and Immunology, 2900 Queen Lane, MCP Hahnemann School of Medicine, Philadelphia, PA 19129, USA
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Srivastava IK, Vaidya AB. A mechanism for the synergistic antimalarial action of atovaquone and proguanil. Antimicrob Agents Chemother 1999; 43:1334-9. [PMID: 10348748 PMCID: PMC89274 DOI: 10.1128/aac.43.6.1334] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A combination of atovaquone and proguanil has been found to be quite effective in treating malaria, with little evidence of the emergence of resistance when atovaquone was used as a single agent. We have examined possible mechanisms for the synergy between these two drugs. While proguanil by itself had no effect on electron transport or mitochondrial membrane potential (DeltaPsim), it significantly enhanced the ability of atovaquone to collapse DeltaPsim when used in combination. This enhancement was observed at pharmacologically achievable doses. Proguanil acted as a biguanide rather than as its metabolite cycloguanil (a parasite dihydrofolate reductase [DHFR] inhibitor) to enhance the atovaquone effect; another DHFR inhibitor, pyrimethamine, also had no enhancing effect. Proguanil-mediated enhancement was specific for atovaquone, since the effects of other mitochondrial electron transport inhibitors, such as myxothiazole and antimycin, were not altered by inclusion of proguanil. Surprisingly, proguanil did not enhance the ability of atovaquone to inhibit mitochondrial electron transport in malaria parasites. These results suggest that proguanil in its prodrug form acts in synergy with atovaquone by lowering the effective concentration at which atovaquone collapses DeltaPsim in malaria parasites. This could explain the paradoxical success of the atovaquone-proguanil combination even in regions where proguanil alone is ineffective due to resistance. The results also suggest that the atovaquone-proguanil combination may act as a site-specific uncoupler of parasite mitochondria in a selective manner.
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Affiliation(s)
- I K Srivastava
- Department of Microbiology and Immunology, MCP Hahnemann School of Medicine, Philadelphia, Pennsylvania 19129, USA
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Pearson PA, Piracha AR, Sen HA, Jaffe GJ. Atovaquone for the treatment of toxoplasma retinochoroiditis in immunocompetent patients. Ophthalmology 1999; 106:148-53. [PMID: 9917796 DOI: 10.1016/s0161-6420(99)90021-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
OBJECTIVE To report the results of a phase I trial to evaluate the safety and efficacy of atovaquone for the treatment of ocular toxoplasmosis in immunocompetent patients. DESIGN Open label, nonrandomized, prospective, clinical trial. PARTICIPANTS Seventeen immunocompetent patients between the ages of 18 and 75 years with clinical and serologic evidence of ocular toxoplasmosis participated. INTERVENTION Treatment of ocular toxoplasmosis with atovaquone tablets (750 mg four times a day) for 3 months. Prednisone (40 mg) tablets were added on day 3 of treatment and tapered as inflammation resolved. MAIN OUTCOME MEASURES Clinical response and patient tolerance to atovaquone therapy for ocular toxoplasmosis. RESULTS Average follow-up was 10 months. Most patients experienced no adverse treatment effects. When present, side effects were usually mild and included rash, pruritus, headache, and nausea. With the exception of one patient, who discontinued treatment at 6 weeks secondary to persistent epigastric discomfort, all patients completed the 12 weeks of therapy. All patients had a favorable response to treatment that began within 1 to 3 weeks. Visual acuity was stabilized or improved in all patients. Median initial visual acuity was 20/200 and median final visual acuity was 20/25. In general, atovaquone was well tolerated. CONCLUSIONS Atovaquone is better tolerated than conventional antitoxoplasmosis therapy and appears to be at least as effective. Atovaquone is a promising alternative for the treatment of ocular toxoplasmosis in immunocompetent patients.
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Affiliation(s)
- P A Pearson
- Department of Ophthalmology, University of Kentucky, Lexington 40536, USA
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Khan AA, Nasr M, Araujo FG. Two 2-hydroxy-3-alkyl-1,4-naphthoquinones with in vitro and in vivo activities against Toxoplasma gondii. Antimicrob Agents Chemother 1998; 42:2284-9. [PMID: 9736550 PMCID: PMC105819 DOI: 10.1128/aac.42.9.2284] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two 3-alkyl-substituted 2-hydroxy-1,4-naphthoquinones, NSC 113452 (NSC52) and NSC 113455 (NSC55), were evaluated for activity against Toxoplasma gondii in vitro and in murine models of acute toxoplasmosis. In vitro, both NSC52 and NSC55 significantly inhibited intracellular replication of T. gondii. In vivo, each compound was examined alone and in combination with other drugs currently used for treatment of human toxoplasmosis. Although none of the compounds protected mice against death when administered orally, both were significantly protective when administered intraperitoneally. In addition, a significant increase in survival was observed when suboptimal doses of each compound were used in combination with suboptimal doses of pyrimethamine or sulfadiazine. These results indicate that combinations of NSC52 or NSC55 with pyrimethamine or sulfadiazine have promising activity against T. gondii.
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Affiliation(s)
- A A Khan
- Department of Immunology and Infectious Diseases, Research Institute, Palo Alto Medical Foundation, Palo Alto, California 94301, USA
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