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Melfi F, Carradori S, Campestre C, Haloci E, Ammazzalorso A, Grande R, D'Agostino I. Emerging compounds and therapeutic strategies to treat infections from Trypanosoma brucei: an overhaul of the last 5-years patents. Expert Opin Ther Pat 2023; 33:247-263. [PMID: 36933190 DOI: 10.1080/13543776.2023.2193328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Abstract
INTRODUCTION Human African Trypanosomiasis is a neglected disease caused by infection from parasites belonging to the Trypanosoma brucei species. Only six drugs are currently available and employed depending on the stage of the infection: pentamidine, suramin, melarsoprol, eflornithine, nifurtimox, and fexinidazole. Joint research projects were launched in an attempt to find new therapeutic options for this severe and often lethal disease. AREAS COVERED After a brief description of the recent literature on the parasite and the disease, we searched for patents dealing with the proposal of new anti-trypanosomiasis agents and, following the PRISMA guidelines, we filtered the results to those published from 2018onwards returning suitable entries, which represent the contemporary landscape of compounds/strategies against Trypanosoma brucei. In addition, some relevant publications from the overall scientific literature were also discussed. EXPERT OPINION This review comprehensively covers and analyzes the most recent advances not only in the discovery of new inhibitors and their structure-activity relationships but also in the assessment of innovative biological targets opening new scenarios in the MedChem field. Lastly, also new vaccines and formulations recently patented were described. However, natural and synthetic compounds were analyzed in terms of inhibitory activity and selective toxicity against human cells.
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Affiliation(s)
- Francesco Melfi
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Simone Carradori
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Cristina Campestre
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Entela Haloci
- Department of Pharmacy, University of Medicine, Tirana, Albania
| | | | - Rossella Grande
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Ilaria D'Agostino
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
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Ehrens A, Hoerauf A, Hübner MP. Eosinophils in filarial infections: Inducers of protection or pathology? Front Immunol 2022; 13:983812. [PMID: 36389745 PMCID: PMC9659639 DOI: 10.3389/fimmu.2022.983812] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/05/2022] [Indexed: 05/29/2024] Open
Abstract
Filariae are parasitic roundworms, which can cause debilitating diseases such as lymphatic filariasis and onchocerciasis. Lymphatic filariasis, also known as elephantiasis, and onchocerciasis, commonly referred to as river blindness, can lead to stigmatizing pathologies and present a socio-economic burden for affected people and their endemic countries. Filariae typically induce a type 2 immune response, which is characterized by cytokines, i.e., IL-4, IL-5 and IL-13 as well as type 2 immune cells including alternatively activated macrophages, innate lymphoid cells and Th2 cells. However, the hallmark characteristic of filarial infections is a profound eosinophilia. Eosinophils are innate immune cells and pivotal in controlling helminth infections in general and filarial infections in particular. By modulating the function of other leukocytes, eosinophils support and drive type 2 immune responses. Moreover, as primary effector cells, eosinophils can directly attack filariae through the release of granules containing toxic cationic proteins with or without extracellular DNA traps. At the same time, eosinophils can be a driving force for filarial pathology as observed during tropical pulmonary eosinophilia in lymphatic filariasis, in dermatitis in onchocerciasis patients as well as adverse events after treatment of onchocerciasis patients with diethylcarbamazine. This review summarizes the latest findings of the importance of eosinophil effector functions including the role of eosinophil-derived proteins in controlling filarial infections and their impact on filarial pathology analyzing both human and experimental animal studies.
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Affiliation(s)
- Alexandra Ehrens
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Marc P. Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
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Tagboto S, Orish V. Drug development for onchocerciasis-the past, the present and the future. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.953061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Onchocerciasis affects predominantly rural communities in Africa, and with small foci in South America and the Yemen. The disease is a major cause of blindness and other significant morbidity and mortality. Control programs have achieved a major impact on the incidence and prevalence of onchocerciasis by interrupting transmission with vector control programs, and treatment with mass drug administration using the microfilaricide ivermectin. Over the last few decades, several microfilaricides have been developed. This initially included diethylcarbamazine, which had significant side effects and is no longer used as such. Ivermectin which is a safe and highly effective microfilaricide and moxidectin which is a longer acting microfilaricide are presently recognized therapies. Suramin was the first effective macrofilaricide but was prohibitively toxic. Certain antibiotics including doxycycline can help eliminate adult worms by targeting its endosymbiont bacteria, Wolbachia pipientis. However, the dosing regimens may make this difficult to use as part of a mass disease control program in endemic areas. It is now widely recognized that treatments that are able to kill or permanently sterilize adult filarial worms should help achieve the elimination of this disease. We summarize in detail the historic drug development in onchocerciasis, including prospective future candidate drugs.
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Krome AK, Becker T, Kehraus S, Schiefer A, Gütschow M, Chaverra-Muñoz L, Hüttel S, Jansen R, Stadler M, Ehrens A, Pogorevc D, Müller R, Hübner MP, Hesterkamp T, Pfarr K, Hoerauf A, Wagner KG, König GM. Corallopyronin A: antimicrobial discovery to preclinical development. Nat Prod Rep 2022; 39:1705-1720. [PMID: 35730490 DOI: 10.1039/d2np00012a] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Covering: August 1984 up to January 2022Worldwide, increasing morbidity and mortality due to antibiotic-resistant microbial infections has been observed. Therefore, better prevention and control of infectious diseases, as well as appropriate use of approved antibacterial drugs are crucial. There is also an urgent need for the continuous development and supply of novel antibiotics. Thus, identifying new antibiotics and their further development is once again a priority of natural product research. The antibiotic corallopyronin A was discovered in the 1980s in the culture broth of the Myxobacterium Corallococcus coralloides and serves, in the context of this review, as a show case for the development of a naturally occurring antibiotic compound. The review demonstrates how a hard to obtain, barely water soluble and unstable compound such as corallopyronin A can be developed making use of sophisticated production and formulation approaches. Corallopyronin A is a bacterial DNA-dependent RNA polymerase inhibitor with a new target site and one of the few representatives of this class currently in preclinical development. Efficacy against Gram-positive and Gram-negative pathogens, e.g., Chlamydia trachomatis, Orientia tsutsugamushi, Staphylococcus aureus, and Wolbachia has been demonstrated. Due to its highly effective in vivo depletion of Wolbachia, which are essential endobacteria of most filarial nematode species, and its robust macrofilaricidal efficacy, corallopyronin A was selected as a preclinical candidate for the treatment of human filarial infections. This review highlights the discovery and production optimization approaches for corallopyronin A, as well as, recent preclinical efficacy results demonstrating a robust macrofilaricidal effect of the anti-Wolbachia candidate, and the solid formulation strategy which enhances the stability as well as the bioavailability of corallopyronin A.
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Affiliation(s)
- Anna K Krome
- Pharmaceutical Technology and Biopharmaceutics, University of Bonn, Germany. .,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Tim Becker
- Pharmaceutical Technology and Biopharmaceutics, University of Bonn, Germany. .,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany
| | - Stefan Kehraus
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Pharmaceutical Biology, University of Bonn, Germany.
| | - Andrea Schiefer
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Michael Gütschow
- Pharmaceutical & Medicinal Chemistry, University of Bonn, Germany
| | | | - Stephan Hüttel
- Department of Microbial Drugs, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Rolf Jansen
- Department of Microbial Drugs, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Marc Stadler
- Department of Microbial Drugs, Helmholtz Centre for Infection Research, Braunschweig, Germany.,German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany
| | - Alexandra Ehrens
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Domen Pogorevc
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany.,Helmholtz Institute for Pharmaceutical Research Saarland, Saarbrucken, Germany
| | - Rolf Müller
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany.,Helmholtz Institute for Pharmaceutical Research Saarland, Saarbrucken, Germany
| | - Marc P Hübner
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Thomas Hesterkamp
- Translational Project Management Office (TPMO), German Center for Infection Research (DZIF), Braunschweig, Germany
| | - Kenneth Pfarr
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Achim Hoerauf
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Karl G Wagner
- Pharmaceutical Technology and Biopharmaceutics, University of Bonn, Germany. .,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany
| | - Gabriele M König
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Germany.,Institute for Pharmaceutical Biology, University of Bonn, Germany.
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Abongwa M, Samje M, Ayimele GA, Babiaka SB, Bulman C, Sakanari J, Koszewski NJ, Verma S, Goff J, Cho-Ngwa F, Martin RJ, Robertson AP. Filaricidal activity of Daniellia oliveri and Psorospermum febrifugum extracts. Parasit Vectors 2021; 14:305. [PMID: 34099047 PMCID: PMC8186089 DOI: 10.1186/s13071-021-04759-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 04/30/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Drugs currently used for controlling onchocerciasis and lymphatic filariasis (LF) are mainly microfilaricidal, with minimal or no effect on the adult worms. For efficient management of these diseases, it is necessary to search for new drugs with macrofilaricidal activities that can be used singly or in combination with existing ones. Daniellia oliveri and Psorospermum febrifugum are two plants commonly used in the local management of these infections in Bambui, a township in the North West Region of Cameroon, but there is currently no documented scientific evidence to support their claimed anthelmintic efficacy and safety. The aim of this study was to provide evidence in support of the search for means to eliminate these diseases by screening extracts and chromatographic fractions isolated from these plants for efficacy against the parasitic roundworms Onchocerca ochengi and Brugia pahangi. METHODS The viability of O. ochengi adult worms was assessed using the MTT/formazan assay. Fully confluent monkey kidney epithelial cells (LLC-MK2) served as the feeder layer for the O. ochengi microfilariae (mfs) assays. Viability of the mfs was assessed by microscopic examination for mean motility scoring (relative to the negative control) every 24 h post addition of an extract. The Worminator system was used to test the effects of the extracts on adult B. pahangi motility, and mean motility units were determined for each worm. Cytotoxicity of the active extracts on N27 cells was assessed using the MTS assay. RESULTS Extracts from D. oliveri and P. febrifugum were effective against the adult roundworms O. ochengi and B. pahangi. Interestingly, extracts showing macrofilaricidal activities against O. ochengi also showed activity against O. ochengi mfs. The hexane stem bark extract of D. oliveri (DOBHEX) was more selective for adult O. ochengi than for mfs, with a half maximal and 100% inhibitory concentration (IC50 and IC100, respectively) against adult O. ochengi of 13.9 and 31.3 μg/ml, respectively. The in vitro cytotoxicity of all active extracts on N27 cells showed selective toxicity for parasites (selectivity index > 1). Bioassay-guided fractionation of the extracts yielded fractions with activity against adult B. pahangi, thus confirming the presence of bioactive principles in the plant extracts. CONCLUSIONS Our study supports the use of D. oliveri and P. febrifugum in the traditional treatment of onchocerciasis and LF. The further purification of active extracts from these plants could yield lead compounds for filarial drug discovery and development.
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Affiliation(s)
- Melanie Abongwa
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Moses Samje
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Faculty of Science, University of Buea, South West Region, Buea, Cameroon.,Department of Biomedical Sciences, Faculty of Health Sciences, University of Bamenda, Bamenda, Cameroon
| | - Godfred A Ayimele
- Department of Chemistry, Faculty of Science, University of Buea, South West Region, Buea, Cameroon
| | - Smith B Babiaka
- Department of Chemistry, Faculty of Science, University of Buea, South West Region, Buea, Cameroon
| | - Christina Bulman
- Center for Discovery and Innovation in Parasitic Diseases, University of California San Francisco, San Francisco, CA, USA
| | - Judy Sakanari
- Center for Discovery and Innovation in Parasitic Diseases, University of California San Francisco, San Francisco, CA, USA
| | - Nick J Koszewski
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Saurabh Verma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Jesse Goff
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Faculty of Science, University of Buea, South West Region, Buea, Cameroon
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
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Kempf DJ, Marsh KC. Assembling Pharma Resources to Tackle Diseases of Underserved Populations. ACS Med Chem Lett 2020; 11:1094-1100. [PMID: 32550987 DOI: 10.1021/acsmedchemlett.0c00051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/27/2020] [Indexed: 01/11/2023] Open
Abstract
Tropical diseases that disproportionally affect the world's poorest people have traditionally been neglected from research efforts toward the discovery and development of new and effective therapies. Over the past two decades, major global health funders have made efforts to bring together various research institutions to work together in these disease areas offering little or no commercial return. This work describes the genesis and growth of an informal program devoted to contributing to new therapies for neglected tropical diseases within the environment of a major biopharmaceutical company (AbbVie).
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Kushnir V, Dmytrenko S, Katilov O, Kushnir N. Itching as the onset of pain (part 2). PAIN MEDICINE 2020. [DOI: 10.31636/pmjua.v5i1.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Itching of the skin is a particularly unpleasant subjective sensation that causes the need to scratch. Physiological itching occurs in response to environmental irritants (friction, insect crawling, temperature changes, etc.) and disappears after elimination of the cause. Pathological itching is caused by changes in the skin or throughout the body and causes a strong need to get rid of itching by combing or any other method. Itching is a common symptom of local (dermatological) or general (systemic) disease. It can be limited (localized) or diffuse (generalized).One of the causes of itching is often noted endocrine diseases and metabolic disorders: hyper- and hypofunction of the thyroid gland, diabetes mellitus and hyperparathyroidism. In thyroid hyperfunction, generalized (inconstant and little-pronounced) itching of the skin is observed in the clinical picture only in 10 % of patients. It is accepted that itching of the skin in thyrotoxicosis syndrome is due to increased activity of kinin in combination with an increase in major metabolism and an increase in body and skin temperature (123).Itching caused by impaired bile secretion is characteristic of many diseases of the liver: primary biliary cirrhosis, sclerosing cholangitis, viral hepatitis caused by cholestasis medications and other causes of obstructive jaundice. It is in these cases that prurigo is usually generalized, but in some typical cases it is more pronounced on the feet and palms. With this pathology, itching is caused by obstruction of the biliary tract, however, and to this day, no close correlation has been found between serum bilirubin and the severity of itching.If it was previously thought that itching in pathology of the peripheral or central nervous system, such as multiple sclerosis, neuropathy, compression or irritation of nerves (e.g., paraesthetic dorsalgia, brachioradial itching) is also a significant symptom, then modern studies prove that in more cases, itching is not characteristic of most pathologies of the nervous system, so after a detailed anamnesis, examination and initial research, the patient should be referred to a related specialist, except in cases of about obvious postherpetic neuropathy, painless paresthesia, or brachioradial itching, which can often be guided in the provision of primary care.Instead, there are some psychological conditions and a number of psychiatric illnesses (obsessive-compulsive disorders, depression, and parasite illusions) that are most commonly diagnosed with the exclusion method. Neurotic squabbles are scattered on the body of the excorii, covered with scales that may occur in any area of the body that the patient may reach, but are often limited by limbs.
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Millington G, Collins A, Lovell C, Leslie T, Yong A, Morgan J, Ajithkumar T, Andrews M, Rushbook S, Coelho R, Catten S, Lee K, Skellett A, Affleck A, Exton L, Mohd Mustapa M, Levell N, McHenry P, Gibbon K, Buckley D, Leslie T, Mallon E, Wakelin S, Ungureanu S, Hunasehally R, Cork M, Johnston G, Chiang N, Natkunarajah J, Worsnop F, Duarte Williamson C, Donnelly J, Towers K, Saunders C, Adbi Salad A, Brain A. British Association of Dermatologists’ guidelines for the investigation and management of generalized pruritus in adults without an underlying dermatosis, 2018. Br J Dermatol 2018; 178:34-60. [DOI: 10.1111/bjd.16117] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2017] [Indexed: 12/20/2022]
Affiliation(s)
- G.W.M. Millington
- Dermatology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - A. Collins
- Haematology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - C.R. Lovell
- Dermatology Department Royal United Hospital Combe Park Bath BA1 3NG U.K
| | - T.A. Leslie
- Dermatology Department Royal Free Hospital Pond Street London NW3 2QGU.K
| | - A.S.W. Yong
- Dermatology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - J.D. Morgan
- General Practitioner Chet Valley Medical Practice 40–48 George Lane London NR14 6QH U.K
| | - T. Ajithkumar
- Oncology Department Addenbrooke's Hospital Hills Road Cambridge CB2 2QQ U.K
| | - M.J. Andrews
- Nephrology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - S.M. Rushbook
- Hepatology Unit Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - R.R. Coelho
- Dermatology Department St George's Hospital Blackshaw Road London SW17 0QT U.K
| | - S.J. Catten
- Dermatology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - K.Y.C. Lee
- Dermatology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - A.M. Skellett
- Dermatology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
| | - A.G. Affleck
- Dermatology Department Ninewells Hospital Dundee DD1 9SY U.K
| | - L.S. Exton
- British Association of Dermatologists Willan House 4 Fitzroy Square London W1T 5HQ U.K
| | - M.F. Mohd Mustapa
- British Association of Dermatologists Willan House 4 Fitzroy Square London W1T 5HQ U.K
| | - N.J. Levell
- Dermatology Department Norfolk and Norwich University Hospital Colney Lane Norwich NR4 7UY U.K
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Mhashilkar AS, Vankayala SL, Liu C, Kearns F, Mehrotra P, Tzertzinis G, Palli SR, Woodcock HL, Unnasch TR. Identification of Ecdysone Hormone Receptor Agonists as a Therapeutic Approach for Treating Filarial Infections. PLoS Negl Trop Dis 2016; 10:e0004772. [PMID: 27300294 PMCID: PMC4907521 DOI: 10.1371/journal.pntd.0004772] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/21/2016] [Indexed: 11/27/2022] Open
Abstract
Background A homologue of the ecdysone receptor has previously been identified in human filarial parasites. As the ecdysone receptor is not found in vertebrates, it and the regulatory pathways it controls represent attractive potential chemotherapeutic targets. Methodology/ Principal Findings Administration of 20-hydroxyecdysone to gerbils infected with B. malayi infective larvae disrupted their development to adult stage parasites. A stable mammalian cell line was created incorporating the B. malayi ecdysone receptor ligand-binding domain, its heterodimer partner and a secreted luciferase reporter in HEK293 cells. This was employed to screen a series of ecdysone agonist, identifying seven agonists active at sub-micromolar concentrations. A B. malayi ecdysone receptor ligand-binding domain was developed and used to study the ligand-receptor interactions of these agonists. An excellent correlation between the virtual screening results and the screening assay was observed. Based on both of these approaches, steroidal ecdysone agonists and the diacylhydrazine family of compounds were identified as a fruitful source of potential receptor agonists. In further confirmation of the modeling and screening results, Ponasterone A and Muristerone A, two compounds predicted to be strong ecdysone agonists stimulated expulsion of microfilaria and immature stages from adult parasites. Conclusions The studies validate the potential of the B. malayi ecdysone receptor as a drug target and provide a means to rapidly evaluate compounds for development of a new class of drugs against the human filarial parasites. The human filarial parasites are the causative agents of two neglected tropical diseases targeted for elimination by the international community. The current elimination programs rely upon the mass distribution of a limited number of drugs, leaving the programs open to failure in the event that resistance develops. Thus, there is a critical need for novel chemotherapeutic agents to supplement the current arsenal. The filarial parasites are ecdysozoans, whose developmental processes are controlled by a master regulator, the ecdysone receptor. Here we validate the potential of the filarial ecdysone receptor as a chemotherapeutic target and report the development of high throughput and virtual screening assays that may be used to compounds that target it.
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Affiliation(s)
- Amruta S. Mhashilkar
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Sai L. Vankayala
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Canhui Liu
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Fiona Kearns
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Priyanka Mehrotra
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - George Tzertzinis
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Subba R. Palli
- Department of Entomology, University of Kentucky, Lexington, Kentucky, United States of America
| | - H. Lee Woodcock
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Thomas R. Unnasch
- Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
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10
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Mhashilkar AS, Adapa SR, Jiang RHY, Williams SA, Zaky W, Slatko BE, Luck AN, Moorhead AR, Unnasch TR. Phenotypic and molecular analysis of the effect of 20-hydroxyecdysone on the human filarial parasite Brugia malayi. Int J Parasitol 2016; 46:333-41. [PMID: 26896576 DOI: 10.1016/j.ijpara.2016.01.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 01/20/2016] [Accepted: 01/22/2016] [Indexed: 11/18/2022]
Abstract
A homologue of the ecdysone receptor has been identified and shown to be responsive to 20-hydroxyecdysone in Brugia malayi. However, the role of this master regulator of insect development has not been delineated in filarial nematodes. Gravid adult female B. malayi cultured in the presence of 20-hydroxyecdysone produced significantly more microfilariae and abortive immature progeny than control worms, implicating the ecdysone receptor in regulation of embryogenesis and microfilarial development. Transcriptome analyses identified 30 genes whose expression was significantly up-regulated in 20-hydroxyecdysone-treated parasites compared with untreated controls. Of these, 18% were identified to be regulating transcription. A comparative proteomic analysis revealed 932 proteins to be present in greater amounts in extracts of 20-hydroxyecdysone-treated adult females than in extracts prepared from worms cultured in the absence of the hormone. Of the proteins exhibiting a greater than two-fold difference in the 20-hydroxyecdysone-treated versus untreated parasite extracts, 16% were involved in transcriptional regulation. RNA interference (RNAi) phenotype analysis of Caenorhabditis elegans orthologs revealed that phenotypes involved in developmental processes associated with embryogenesis were significantly over-represented in the transcripts and proteins that were up-regulated by exposure to 20-hydroxyecdysone. Taken together, the transcriptomic, proteomic and phenotypic data suggest that the filarial ecdysone receptor may play a role analogous to that in insects, where it serves as a regulator of egg development.
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Affiliation(s)
- Amruta S Mhashilkar
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Swamy R Adapa
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Rays H Y Jiang
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Steven A Williams
- Department of Biological Sciences, 100 Green Street, Ford Hall, Smith College, Northampton, MA 01063, USA
| | - Weam Zaky
- Department of Biological Sciences, 100 Green Street, Ford Hall, Smith College, Northampton, MA 01063, USA
| | - Barton E Slatko
- Genome Biology Division, Molecular Parasitology Group, New England Biolabs, 240 County Road, Ipswich, MA 01938, USA
| | - Ashley N Luck
- Genome Biology Division, Molecular Parasitology Group, New England Biolabs, 240 County Road, Ipswich, MA 01938, USA
| | - Andrew R Moorhead
- Department of Infectious Diseases, University of Georgia, College of Veterinary Medicine, 501 D. W. Brooks Drive, Athens, GA 30602, USA
| | - Thomas R Unnasch
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA.
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11
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Ceballos L, Alvarez L, Mackenzie C, Geary T, Lanusse C. Pharmacokinetic comparison of different flubendazole formulations in pigs: A further contribution to its development as a macrofilaricide molecule. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2015; 5:178-84. [PMID: 27120064 PMCID: PMC4846999 DOI: 10.1016/j.ijpddr.2015.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/14/2015] [Accepted: 09/15/2015] [Indexed: 11/30/2022]
Abstract
Despite the well established ivermectin activity against microfilaria, the success of human filariasis control programmes requires the use of a macrofilaricide compound. Different in vivo trials suggest that flubendazole (FLBZ), an anthelmintic benzimidazole compound, is a highly efficacious and potent macrofilaricide. However, since serious injection site reactions were reported in humans after the subcutaneous FLBZ administration, the search for alternative pharmaceutical strategies to improve the systemic availability of FLBZ has acquired special relevance both in human and veterinary medicine. The goal of the current experimental work was to compare the pharmacokinetic plasma behavior of FLBZ, and its metabolites, formulated as either an aqueous hydroxypropyl- β -cyclodextrin-solution (HPBCD), an aqueous carboxymethyl cellulose-suspension (CMC) or a Tween 80-based formulation, in pigs. Animals were allocated into three groups and treated (2 mg/kg) with FLBZ formulated as either a HPBCD-solution (oral), CMC-suspension (oral) or Tween 80-based formulation (subcutaneous). Only trace amounts of FLBZ parent drug and its reduced metabolite were measured after administration of the different FLBZ formulations in pigs. The hydrolyzed FLBZ (H-FLBZ) metabolite was the main analyte recovered in the bloodstream in pigs treated with the three experimental FLBZ formulations. The oral administration of the HPBCD-solution accounted for significantly higher (P < 0.05) Cmax and AUC (23.1 ± 4.4 μg h/mL) values for the main metabolite (H-FLBZ), compared with those observed for the oral CMC-suspension (AUC = 3.5 ± 1.0 μg h/mL) and injectable Tween 80-based formulation (AUC: 7.5 ± 1.7 μg h/mL). The oral administration of the HPBCD-solution significantly improved the poor absorption pattern (indirectly assessed as the H-FLBZ plasma concentrations) observed after the oral administration of the FLBZ-CMC suspension or the subcutaneous injection of the Tween 80 FLBZ formulation to pigs. Overall, the work reported here indicates that FLBZ pharmacokinetic behavior can be markedly changed by the pharmaceutical formulation. The pharmacokinetics of three different FLBZ formulations was assessed in pigs. Hydrolyzed-FLBZ was the main metabolite detected in pigs given the formulations. Traces of FLBZ and reduced-FLBZ were measured after administration of FLBZ. Oral administration of FLBZ-HPBCD solution resulted in a high systemic H-FLBZ exposure. Similar FLBZ plasma exposure was observed after parenteral FLBZ-Tween 80 and HPBCD administration.
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Affiliation(s)
- L Ceballos
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, UNCPBA, Campus Universitario, 7000 Tandil, Argentina.
| | - L Alvarez
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, UNCPBA, Campus Universitario, 7000 Tandil, Argentina
| | - C Mackenzie
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - T Geary
- Institute of Parasitology, McGill University, Ste-Anne-de-Bellevue QC H9X 3V9 Canada
| | - C Lanusse
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, UNCPBA, Campus Universitario, 7000 Tandil, Argentina
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12
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Debrah AY, Specht S, Klarmann-Schulz U, Batsa L, Mand S, Marfo-Debrekyei Y, Fimmers R, Dubben B, Kwarteng A, Osei-Atweneboana M, Boakye D, Ricchiuto A, Büttner M, Adjei O, Mackenzie CD, Hoerauf A. Doxycycline Leads to Sterility and Enhanced Killing of Female Onchocerca volvulus Worms in an Area With Persistent Microfilaridermia After Repeated Ivermectin Treatment: A Randomized, Placebo-Controlled, Double-Blind Trial. Clin Infect Dis 2015; 61:517-26. [PMID: 25948064 PMCID: PMC4518165 DOI: 10.1093/cid/civ363] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 03/23/2015] [Indexed: 11/23/2022] Open
Abstract
Sub-optimal responses to ivermectin (IVM) have emerged. Targeting the Onchocerca volvulus Wolbachia endosymbionts with doxycycline is effective in clearing microfilariae in onchocerciasis patients with persistent microfilaridermia and in enhanced killing of adult worms after repeated standard IVM treatment. Background. Ivermectin (IVM) has been the drug of choice for the treatment of onchocerciasis. However, there have been reports of persistent microfilaridermia in individuals from an endemic area in Ghana after many rounds of IVM, raising concerns of suboptimal response or even the emergence of drug resistance. Because it is considered risky to continue relying only on IVM to combat this phenomenon, we assessed the effect of targeting the Onchocerca volvulus Wolbachia endosymbionts with doxycycline for these individuals with suboptimal response. Methods. One hundred sixty-seven patients, most of them with multiple rounds of IVM, were recruited in areas with IVM suboptimal response and treated with 100 mg/day doxycycline for 6 weeks. Three and 12 months after doxycycline treatment, patients took part in standard IVM treatment. Results. At 20 months after treatment, 80% of living female worms from the placebo group were Wolbachia positive, whereas only 5.1% in the doxycycline-treated group contained bacteria. Consistent with interruption of embryogenesis, none of the nodules removed from doxycycline-treated patients contained microfilariae, and 97% of those patients were without microfilaridermia, in contrast to placebo patients who remained at pretreatment levels (P < .001). Moreover, a significantly enhanced number of dead worms were observed after doxycycline. Conclusions. Targeting the Wolbachia in O. volvulus is effective in clearing microfilariae in the skin of onchocerciasis patients with persistent microfilaridermia and in enhanced killing of adult worms after repeated standard IVM treatment. Strategies can now be developed that include doxycycline to control onchocerciasis in areas where infections persist despite the frequent use of IVM. Clinical Trials Registration. ISRCTN 66649839.
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Affiliation(s)
- Alexander Yaw Debrah
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology Kumasi Centre for Collaborative Research in Tropical Medicine, Ghana
| | - Sabine Specht
- Institutes for Medical Microbiology, Immunology and Parasitology
| | - Ute Klarmann-Schulz
- Institutes for Medical Microbiology, Immunology and Parasitology Medical Biometry, Informatics and Epidemiology, University of Bonn, Germany
| | - Linda Batsa
- Kumasi Centre for Collaborative Research in Tropical Medicine, Ghana
| | - Sabine Mand
- Institutes for Medical Microbiology, Immunology and Parasitology
| | | | - Rolf Fimmers
- Medical Biometry, Informatics and Epidemiology, University of Bonn, Germany
| | - Bettina Dubben
- Institutes for Medical Microbiology, Immunology and Parasitology
| | | | | | - Daniel Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra
| | - Arcangelo Ricchiuto
- Institutes for Medical Microbiology, Immunology and Parasitology Medical Biometry, Informatics and Epidemiology, University of Bonn, Germany
| | | | - Ohene Adjei
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Charles D Mackenzie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, United Kingdom
| | - Achim Hoerauf
- Institutes for Medical Microbiology, Immunology and Parasitology
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13
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Wanji S, Kengne-Ouafo JA, Esum ME, Chounna PWN, Tendongfor N, Adzemye BF, Eyong JEE, Jato I, Datchoua-Poutcheu FR, Kah E, Enyong P, Taylor DW. Situation analysis of parasitological and entomological indices of onchocerciasis transmission in three drainage basins of the rain forest of South West Cameroon after a decade of ivermectin treatment. Parasit Vectors 2015; 8:202. [PMID: 25886166 PMCID: PMC4393872 DOI: 10.1186/s13071-015-0817-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 03/19/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Community-Directed Treatment with Ivermectin (CDTI) is the main strategy adopted by the African Programme for Onchocerciasis control (APOC). Recent reports from onchocerciasis endemic areas of savannah zones have demonstrated the feasibility of disease elimination through CDTI. Such information is lacking in rain forest zones. In this study, we investigated the parasitological and entomological indices of onchocerciasis transmission in three drainage basins in the rain forest area of Cameroon [after over a decade of CDTI]. River basins differed in terms of river number and their flow rates; and were characterized by high pre-control prevalence rates (60-98%). METHODS Nodule palpation and skin snipping were carried out in the study communities to determine the nodule rates, microfilarial prevalences and intensity. Simulium flies were caught at capture points and dissected to determine the biting, parous, infection and infective rates and the transmission potential. RESULTS The highest mean microfilaria (mf) prevalence was recorded in the Meme (52.7%), followed by Mungo (41.0%) and Manyu drainage basin (33.0%). The same trend was seen with nodule prevalence between the drainage basins. Twenty-three (23/39) communities (among which 13 in the Meme) still had mf prevalence above 40%. All the communities surveyed had community microfilarial loads (CMFL) below 10 mf/skin snip (ss). The infection was more intense in the Mungo and Meme. The intensity of infection was still high in younger individuals and children less than 10 years of age. Transmission potentials as high as 1211.7 infective larvae/person/month were found in some of the study communities. Entomological indices followed the same trend as the parasitological indices in the three river basins with the Meme having the highest values. CONCLUSION When compared with pre-control data, results of the present study show that after over a decade of CDTI, the burden of onchocerciasis has reduced. However, transmission is still going on in this study site where loiasis and onchocerciasis are co-endemic and where ecological factors strongly favour the onchocerciasis transmission. The possible reasons for this persistent and differential transmission despite over a decade of control efforts using ivermectin are discussed.
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Affiliation(s)
- Samuel Wanji
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon.
| | - Jonas A Kengne-Ouafo
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon.
| | - Mathias E Esum
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon.
| | - Patrick W N Chounna
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon.
| | - Nicholas Tendongfor
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon.
| | - Bridget F Adzemye
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon.
| | - Joan E E Eyong
- Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon. .,Department of Biological Sciences, Faculty of Science, University of Bamenda, P.O. Box 39, Bambili, North West Region, Bamenda, Cameroon.
| | - Isaac Jato
- Tropical Medicine Research station, P.O. Box 55, Kumba, Cameroon.
| | - Fabrice R Datchoua-Poutcheu
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and Environment, P.O. Box 474, Buea, Cameroon.
| | - Elvis Kah
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Department of Geography, University of Yaounde1, Yaounde, Cameroon.
| | - Peter Enyong
- Parasite and Vectors Research Unit, Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Tropical Medicine Research station, P.O. Box 55, Kumba, Cameroon.
| | - David W Taylor
- Division of Pathway Medicine, School for Biomedical Studies, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
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14
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Halliday A, Guimaraes AF, Tyrer HE, Metuge HM, Patrick CNW, Arnaud KOJ, Kwenti TDB, Forsbrook G, Steven A, Cook D, Enyong P, Wanji S, Taylor MJ, Turner JD. A murine macrofilaricide pre-clinical screening model for onchocerciasis and lymphatic filariasis. Parasit Vectors 2014; 7:472. [PMID: 25338621 PMCID: PMC4212127 DOI: 10.1186/s13071-014-0472-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/02/2014] [Indexed: 03/26/2023] Open
Abstract
Background New drugs effective against adult filariae (macrofilaricides) would accelerate the elimination of lymphatic filariasis and onchocerciasis. Anti-Onchocerca drug development is hampered by the lack of a facile model. We postulated that SCID mice could be developed as a fmacrofilaricide screening model. Methods The filaricides: albendazole (ABZ), diethylcarbamazine (DEC), flubendazole (FBZ), ivermectin (IVM) and the anti-Wolbachia macrofilaricide, minocycline (MIN) were tested in Brugia malayi (Bm)-parasitized BALB/c SCID mice vs vehicle control (VC). Responses were compared to BALB/c wild type (WT). Onchocerca ochengi male worms or onchocercomata were surgically implanted into BALB/c SCID, CB.17 SCID, BALB/c WT mice or Meriones gerbils. Survival was evaluated at 7–15 days. BALB/c SCID were tested to evaluate the responsiveness of pre-clinical macrofilaricides FBZ and rifapentine (RIFAP) against male Onchocerca. Results WT and SCID responded with >95% efficacy following ABZ or DEC treatments against Bm larvae (P < 0.0001). IVM was partially filaricidal against Bm larvae in WT and SCID (WT; 39.8%, P = 0.0356 and SCID; 56.7%, P = 0.026). SCID responded similarly to WT following IVM treatment of microfilaraemias (WT; 79%, P = 0.0194. SCID; 76%, P = 0.0473). FBZ induced a total macrofilaricidal response against adult Bm in WT and SCID (WT; P = 0.0067, SCID; P = 0.0071). MIN induced a >90% reduction in Bm Wolbachia burdens (P < 0.0001) and a blockade of microfilarial release (P = 0.0215) in SCID. Male Onchocerca survival was significantly higher in SCID vs WT mice, but not gerbils, after +15 days (60% vs 22% vs 39% P = 0.0475). Onchocercoma implants had engrafted into host tissues, with evidence of neovascularisation, after +7 days and yielded viable macro/microfilariae ex vivo. FBZ induced a macrofilaricidal effect in Onchocerca male implanted SCID at +5 weeks (FBZ; 1.67% vs VC; 43.81%, P = 0.0089). Wolbachia loads within male Onchocerca were reduced by 99% in implanted SCID receiving RIFAP for +2 weeks. Conclusions We have developed a ‘pan-filarial’ small animal research model that is sufficiently robust, with adequate capacity and throughput, to screen existing and future pre-clinical candidate macrofilaricides. Pilot data suggests a murine onchocercoma xenograft model is achievable.
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Affiliation(s)
- Alice Halliday
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Ana F Guimaraes
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Hayley E Tyrer
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | | | - Chounna Ndongmo Winston Patrick
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon. .,Department of Microbiology and Parasitology, Parasite and Vector Research Unit, University of Buea, Buea, Cameroon.
| | - Kengne-Ouafo Jonas Arnaud
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon. .,Department of Microbiology and Parasitology, Parasite and Vector Research Unit, University of Buea, Buea, Cameroon.
| | - Tayong Dizzle Bita Kwenti
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon. .,Department of Microbiology and Parasitology, Parasite and Vector Research Unit, University of Buea, Buea, Cameroon.
| | - George Forsbrook
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Andrew Steven
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Darren Cook
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Peter Enyong
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon.
| | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment, Buea, Cameroon. .,Department of Microbiology and Parasitology, Parasite and Vector Research Unit, University of Buea, Buea, Cameroon.
| | - Mark J Taylor
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Joseph D Turner
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
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15
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Awadzi K, Opoku NO, Attah SK, Lazdins-Helds J, Kuesel AC. A randomized, single-ascending-dose, ivermectin-controlled, double-blind study of moxidectin in Onchocerca volvulus infection. PLoS Negl Trop Dis 2014; 8:e2953. [PMID: 24968000 PMCID: PMC4072596 DOI: 10.1371/journal.pntd.0002953] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/06/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Control of onchocerciasis as a public health problem in Africa relies on annual mass ivermectin distribution. New tools are needed to achieve elimination of infection. This study determined in a small number of Onchocerca volvulus infected individuals whether moxidectin, a veterinary anthelminthic, is safe enough to administer it in a future large study to further characterize moxidectin's safety and efficacy. Effects on the parasite were also assessed. METHODOLOGY/PRINCIPAL FINDINGS Men and women from a forest area in South-eastern Ghana without ivermectin mass distribution received a single oral dose of 2 mg (N = 44), 4 mg (N = 45) or 8 mg (N = 38) moxidectin or 150 µg/kg ivermectin (N = 45) with 18 months follow up. All ivermectin and 97%-100% of moxidectin treated participants had Mazzotti reactions. Statistically significantly higher percentages of participants treated with 8 mg moxidectin than participants treated with ivermectin experienced pruritus (87% vs. 56%), rash (63% vs. 42%), increased pulse rate (61% vs. 36%) and decreased mean arterial pressure upon 2 minutes standing still after ≥5 minutes supine relative to pre-treatment (61% vs. 27%). These reactions resolved without treatment. In the 8 mg moxidectin and ivermectin arms, the mean±SD number of microfilariae/mg skin were 22.9±21.1 and 21.2±16.4 pre-treatment and 0.0±0.0 and 1.1±4.2 at nadir reached 1 and 3 months after treatment, respectively. At 6 months, values were 0.0±0.0 and 1.6±4.5, at 12 months 0.4±0.9 and 3.4±4.4 and at 18 months 1.8±3.3 and 4.0±4.8, respectively, in the 8 mg moxidectin and ivermectin arm. The reduction from pre-treatment values was significantly higher after 8 mg moxidectin than after ivermectin treatment throughout follow up (p<0.01). CONCLUSIONS/SIGNIFICANCE The 8 mg dose of moxidectin was safe enough to initiate the large study. Provided its results confirm those from this study, availability of moxidectin to control programmes could help them achieve onchocerciasis elimination objectives. TRIAL REGISTRATION ClinicalTrials.gov NCT00300768.
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Affiliation(s)
- Kwablah Awadzi
- Onchocerciasis Chemotherapy Research Centre, Hohoe, Ghana
| | | | - Simon K. Attah
- Onchocerciasis Chemotherapy Research Centre, Hohoe, Ghana
- University of Ghana Medical School, Department of Microbiology, Accra, Ghana
| | - Janis Lazdins-Helds
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Annette C. Kuesel
- UNICEF/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
- * E-mail:
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16
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Abstract
Two of the major filarial infections, lymphatic filariasis (LF) and onchocerciasis, affect 150 million people, while 1 billion living in endemic areas are at risk of infection. Public health programs to control these infections have successfully existed for years and have evolved from activities driven by the WHO into global programs with public-private partnerships. Currently, these programs use yearly mass application of drugs that mainly kill the larval stages (the microfilariae), with the aim of preventing uptake by the transmitting insect vectors and thus, to block transmission and reduce the infections to such levels that in 15-30 years from now, they will no longer pose a public health problem. While the programs have been very successful in general, there are drawbacks such as coverage being too low within the population, reappearance of infection by migration of infected people into controlled areas, targeting of a stage (the microfilaria) that does not induce pathology in LF and thus lowers compliance, and the potential development of drug resistance, first indications of which have been clearly observed in onchocerciasis. In addition, even without drawbacks, program scopes are not the eradication of filarial infections, which is, however, an ultimate goal of control activities. There is therefore an unequivocal call for the development of higher efficient, complementary chemotherapeutical approaches that lead to a long-lasting reduction of the pathology-inducing worm stages; that is, microfilariae in onchocerciasis and adult worms in LF, or to a macrofilaricidal effect. The recent discovery that depletion of Wolbachia endosymbionts by tetracycline antibiotics leads to long-lasting sterility of adult female worms in onchocerciasis and a macrofilaricidal effect in LF fulfils these requirements. Successful regimens have already been published and agreed upon for use by expert panels. While these regimens are still too long for mass application, the antiwolbachial chemotherapy can currently be applied in the form of a suitable doxycycline regimen for 6 weeks for the treatment of individuals, and exploited in the future for the development of new drugs suitable for mass application. In addition, first data suggest that Wolbachia may also be major mediators of lymphangiogenesis and that their depletion is associated with reduction of lymph vessel-specific vascular endothelial growth factors and reduced lymph vessel size.
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Affiliation(s)
- Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Clinic Bonn, 53105 Bonn, Germany.
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17
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Validation of a remote sensing model to identify Simulium damnosum s.l. breeding sites in Sub-Saharan Africa. PLoS Negl Trop Dis 2013; 7:e2342. [PMID: 23936571 PMCID: PMC3723572 DOI: 10.1371/journal.pntd.0002342] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/15/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Recently, most onchocerciasis control programs have begun to focus on elimination. Developing an effective elimination strategy relies upon accurately mapping the extent of endemic foci. In areas of Africa that suffer from a lack of infrastructure and/or political instability, developing such accurate maps has been difficult. Onchocerciasis foci are localized near breeding sites for the black fly vectors of the infection. The goal of this study was to conduct ground validation studies to evaluate the sensitivity and specificity of a remote sensing model developed to predict S. damnosum s.l. breeding sites. METHODOLOGY/PRINCIPAL FINDINGS Remote sensing images from Togo were analyzed to identify areas containing signature characteristics of S. damnosum s.l. breeding habitat. All 30 sites with the spectral signature were found to contain S. damnosum larvae, while 0/52 other sites judged as likely to contain larvae were found to contain larvae. The model was then used to predict breeding sites in Northern Uganda. This area is hyper-endemic for onchocerciasis, but political instability had precluded mass distribution of ivermectin until 2009. Ground validation revealed that 23/25 sites with the signature contained S. damnosum larvae, while 8/10 sites examined lacking the signature were larvae free. Sites predicted to have larvae contained significantly more larvae than those that lacked the signature. CONCLUSIONS/SIGNIFICANCE This study suggests that a signature extracted from remote sensing images may be used to predict the location of S. damnosum s.l. breeding sites with a high degree of accuracy. This method should be of assistance in predicting communities at risk for onchocerciasis in areas of Africa where ground-based epidemiological surveys are difficult to implement.
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18
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Geary TG, Mackenzie CD. Progress and challenges in the discovery of macrofilaricidal drugs. Expert Rev Anti Infect Ther 2013; 9:681-95. [PMID: 21819332 DOI: 10.1586/eri.11.76] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Control of human filarial infections currently depends on chemotherapeutic strategies predominantly directed at microfilariae. Doxycycline therapy in an extended daily dose regimen sterilizes and kills adult stages, but the utility of this drug for routine field use remains an issue of concern. No macrofilaricidal drugs with efficacy after one or two doses are available for use, delaying the achievement of the elimination or eradication of onchocerciasis and lymphatic filariasis. Moxidectin, a macrocyclic lactone, is currently in clinical trials for onchocerciasis. A few other drugs that have already been approved for use in veterinary practice or in human medicine for other indications are available for investigation. Early drug discovery pipelines are poorly populated and the process of macrofilaricide discovery and development remains highly challenging. In particular, the lack of convenient, validated animal models in an antifilarial drug discovery pathway is an unresolved issue.
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Affiliation(s)
- Timothy G Geary
- Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue QC, H9X 3V9, Canada.
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Spencer PS, Vandemaele K, Richer M, Palmer VS, Chungong S, Anker M, Ayana Y, Opoka ML, Klaucke BN, Quarello A, Tumwine JK. Nodding syndrome in Mundri county, South Sudan: environmental, nutritional and infectious factors. Afr Health Sci 2013; 13:183-204. [PMID: 24235915 PMCID: PMC3824482 DOI: 10.4314/ahs.v13i2.2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Nodding Syndrome is a seizure disorder of children in Mundri County, Western Equatoria, South Sudan. The disorder is reported to be spreading in South Sudan and northern Uganda. OBJECTIVE To describe environmental, nutritional, infectious, and other factors that existed before and during the de novo 1991 appearance and subsequent increase in cases through 2001. METHODS Household surveys, informant interviews, and case-control studies conducted in Lui town and Amadi village in 2001-2002 were supplemented in 2012 by informant interviews in Lui and Juba, South Sudan. RESULTS Nodding Syndrome was associated with Onchocerca volvulus and Mansonella perstans infections, with food use of a variety of sorghum (serena) introduced as part of an emergency relief program, and was inversely associated with a history of measles infection. There was no evidence to suggest exposure to a manmade neurotoxic pollutant or chemical agent, other than chemically dressed seed intended for planting but used for food. Food use of cyanogenic plants was documented, and exposure to fungal contaminants could not be excluded. CONCLUSION Nodding Syndrome in South Sudan has an unknown etiology. Further research is recommended on the association of Nodding Syndrome with onchocerciasis/mansonelliasis and neurotoxins in plant materials used for food.
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Affiliation(s)
- P S Spencer
- Department of Neurology, School of Medicine; Senior Scientist, Center for Research on Occupational and Environmental Toxicology, and Director, Global Health Center, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, L356, Portland, Oregon 97239, USA
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Liu C, Enright T, Tzertzinis G, Unnasch TR. Identification of genes containing ecdysone response elements in the genome of Brugia malayi. Mol Biochem Parasitol 2012; 186:38-43. [PMID: 23017214 DOI: 10.1016/j.molbiopara.2012.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 09/11/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
Abstract
Recent studies have demonstrated that filarial parasites contain a functional homologue of the insect ecdysone receptor (EcR). As a first step in deciphering the physiological role that ecdysteroids play in filarial parasites, adult female parasites cultured in the presence and absence of 20-OH ecdysone were metabolically labeled. Gel electrophoretic analysis of proteins extracted from the cultured parasites revealed changes in the level of expression of several proteins, indicating that adult female parasites contained an ecdysone-responsive gene network. A bioinformatic analysis was then conducted to identify putative ecdysone response elements (EcREs) in the Brugia malayi genome. A total of 18 genes were identified that contained putative EcREs located in the 4 kbp upstream from the start of their open reading frames. The most common functional classifications of the encoded proteins were factors involved in transcription and metabolism. These genes revealed a number of different developmental patterns of transcription. The promoter of one EcRE-containing gene was cloned into a luciferase reporter vector and transfected into B. malayi embryos. Reporter gene expression from embryos transfected with this construct was up-regulated by 20-OH ecdysone. Deletion and substitution mutations in the canonical EcRE resulted in a loss of the ecdysone response. These results demonstrate the presence of functional EcREs in the B. malayi genome.
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Affiliation(s)
- Canhui Liu
- Global Health Infectious Disease Research Program, University of South Florida, Tampa, FL 33620, USA
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Hoerauf A, Pfarr K, Mand S, Debrah AY, Specht S. Filariasis in Africa--treatment challenges and prospects. Clin Microbiol Infect 2011; 17:977-85. [PMID: 21722251 DOI: 10.1111/j.1469-0691.2011.03586.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Lymphatic filariasis (LF) and onchocerciasis are parasitic nematode infections that are responsible for a major disease burden in the African continent. Disease symptoms are induced by the immune reactions of the host, with lymphoedema and hydrocoele in LF, and dermatitis and ocular inflammation in onchocerciasis. Wuchereria bancrofti and Onchocerca volvulus, the species causing LF and onchocerciasis in Africa, live in mutual symbiosis with Wolbachia endobacteria, which cause a major part of the inflammation leading to symptoms and are antibiotic targets for treatment. The standard microfilaricidal drugs ivermectin and albendazole are used in mass drug administration programmes, with the aim of interrupting transmission, with a consequent reduction in the burden of infection and, in some situations, leading to regional elimination of LF and onchocerciasis. Co-endemicity of Loa loa with W. bancrofti or O. volvulus is an impediment to mass drug administration with ivermectin and albendazole, owing to the risk of encephalopathy being encountered upon administration of ivermectin. Research into new treatment options is exploring several improved delivery strategies for the classic drugs or new antibiotic treatment regimens for anti-wolbachial chemotherapy.
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Affiliation(s)
- A Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Sigmund Freud Strasse, Bonn, Germany.
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Hoerauf A, Specht S, Büttner M, Pfarr K, Mand S, Fimmers R, Marfo-Debrekyei Y, Konadu P, Debrah AY, Bandi C, Brattig N, Albers A, Larbi J, Batsa L, Taylor MJ, Adjei O, Büttner DW. Wolbachia endobacteria depletion by doxycycline as antifilarial therapy has macrofilaricidal activity in onchocerciasis: a randomized placebo-controlled study. Med Microbiol Immunol 2008; 197:295-311. [PMID: 17999080 PMCID: PMC2668626 DOI: 10.1007/s00430-007-0062-1] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Indexed: 11/03/2022]
Abstract
In a randomized, placebo-controlled trial in Ghana, 67 onchocerciasis patients received 200-mg/day doxycycline for 4-6 weeks, followed by ivermectin (IVM) after 6 months. After 6-27 months, efficacy was evaluated by onchocercoma histology, PCR and microfilariae determination. Administration of doxycycline resulted in endobacteria depletion and female worm sterilization. The 6-week treatment was macrofilaricidal, with >60% of the female worms found dead, despite the presence of new, Wolbachia-containing worms acquired after the administration of doxycycline. Doxycycline may be developed as second-line drug for onchocerciasis, to be administered in areas without transmission, in foci with IVM resistance and in areas with Loa co-infections.
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Affiliation(s)
- Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Clinic, Bonn, Sigmund-Freud-Strasse 25, Bonn, Germany.
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Taylor MJ, Bandi C, Hoerauf A. Wolbachia.Bacterial Endosymbionts of Filarial Nematodes. ADVANCES IN PARASITOLOGY 2005; 60:245-84. [PMID: 16230105 DOI: 10.1016/s0065-308x(05)60004-8] [Citation(s) in RCA: 265] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Filarial nematodes are important helminth parasites of the tropics and a leading cause of global disability. They include species responsible for onchocerciasis, lymphatic filariasis and dirofilariasis. A unique feature of these nematodes is their dependency upon a symbiotic intracellular bacterium, Wolbachia, which is essential for normal development and fertility. Advances in our understanding of the symbiosis of Wolbachia bacteria with filarial nematodes have made rapid progress in recent years. Here we summarise our current understanding of the evolution of the symbiotic association together with insights into the functional basis of the interaction derived from genomic analysis. Also we discuss the contribution of Wolbachia to inflammatory-mediated pathogenesis and adverse reactions to anti-filarial drugs and describe the outcome of recent field trials using antibiotics as a promising new tool for the treatment of filarial infection and disease.
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Affiliation(s)
- Mark J Taylor
- Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
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Molyneux DH, Bradley M, Hoerauf A, Kyelem D, Taylor MJ. Mass drug treatment for lymphatic filariasis and onchocerciasis. Trends Parasitol 2003; 19:516-22. [PMID: 14580963 DOI: 10.1016/j.pt.2003.09.004] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- David H Molyneux
- Lymphatic Filariasis Support Centre, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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