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Haapanen S, Barker H, Carta F, Supuran CT, Parkkila S. Novel Drug Screening Assay for Acanthamoeba castellanii and the Anti-Amoebic Effect of Carbonic Anhydrase Inhibitors. J Med Chem 2024; 67:152-164. [PMID: 38150360 PMCID: PMC10788897 DOI: 10.1021/acs.jmedchem.3c01020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/29/2023]
Abstract
Acanthamoeba castellanii is an amoeba that inhabits soil and water in every part of the world. Acanthamoeba infection of the eye causes keratitis and can lead to a loss of vision. Current treatment options are only moderately effective, have multiple harmful side effects, and are tedious. In our study, we developed a novel drug screening method to define the inhibitory properties of potential new drugs against A. castellanii in vitro. We found that the clinically used carbonic anhydrase inhibitors, acetazolamide, ethoxzolamide, and dorzolamide, have promising antiamoebic properties.
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Affiliation(s)
- Susanna Haapanen
- Faculty
of Medicine and Health Technology, Tampere
University, FI-33520 Tampere, Finland
| | - Harlan Barker
- Faculty
of Medicine and Health Technology, Tampere
University, FI-33520 Tampere, Finland
- Fimlab
Ltd, Tampere University Hospital, FI-33520 Tampere, Finland
| | - Fabrizio Carta
- Neurofarba
Department, Sezione di Chimica Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via U. Schiff 6, Sesto Fiorentino, I-50019 Firenze, Italy
| | - Claudiu T. Supuran
- Neurofarba
Department, Sezione di Chimica Farmaceutica e Nutraceutica, Università degli Studi di Firenze, Via U. Schiff 6, Sesto Fiorentino, I-50019 Firenze, Italy
| | - Seppo Parkkila
- Faculty
of Medicine and Health Technology, Tampere
University, FI-33520 Tampere, Finland
- Fimlab
Ltd, Tampere University Hospital, FI-33520 Tampere, Finland
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2
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Latifi A, Mohebali M, Yasami S, Soleimani M, Rezaian M, Kazemirad E. Comparing cytotoxicity and efficacy of miltefosine and standard antimicrobial agents against Acanthamoeba trophozoites and cyst forms: An in vitro study. Acta Trop 2023; 247:107009. [PMID: 37643658 DOI: 10.1016/j.actatropica.2023.107009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/22/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
Acanthamoeba keratitis (AK) is an eye disease often occurring in contact lens wearers. AK treatment is prolonged and requires multiple drugs, which can lead to adverse effects. Our study aimed to compare the in vitro activities and safety of Miltefosine with that of conventional antimicrobial agents used to treat AK. Acanthamoeba castellanii genotype T4 was obtained from a patient with keratitis and subjected to in vitro susceptibility testing with various antimicrobial agents, including Chlorhexidine (CHX), Pentamidine isethionate (PI)Polyhexamethylene biguanide (PHMB), and Miltefosine to assess their efficacy against Acanthamoeba trophozoites and cyst. The cytotoxicity of the agents was evaluated in Vero cells, and their selectivity indexes (SI) were calculated. Chlorhexidine exhibited the highest amoebicidal activity with the highest selectivity index against the trophozoite and cyst, ranging from 1.17 to 8.35. The selectivity index of PHMB is slightly comparable to Chlorhexidine, exhibiting significant anti-Acanthamoeba activity. On the other hand, Pentamidine isethionate and Miltefosine displayed low SI among the compounds. Pentamidine isethionate was effective at high concentrations, which was toxic. Miltefosine exhibited the lowest cytotoxicity; nevertheless, due to the lowest anti-Acanthamoeba activity presented a low selectivity against the parasite. Further studies on more clinical samples and prolonged incubation time should be done to investigate the effectiveness and toxicity of drugs in both in vitro and in vivo conditions.
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Affiliation(s)
- Alireza Latifi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Mohebali
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Center for Research of Endemic Parasites of Iran, Tehran University of Medical Sciences, Tehran, Iran
| | - Setayesh Yasami
- Department of Parasitology, Pasteur Institute of Iran, Tehran, Iran
| | - Mohammad Soleimani
- Department of Ocular Trauma and Emergency, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mostafa Rezaian
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Elham Kazemirad
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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Randag AC, de Kroon L, Otten H, Arias Claro-Handgraaf C, Schimmer B, Kortbeek T, van Rooij J, Stelma FF. In Vitro Effectiveness of Soft Contact Lens Solutions Available on the Dutch Market against Acanthamoeba Species. Pathogens 2023; 12:pathogens12020214. [PMID: 36839486 PMCID: PMC9959425 DOI: 10.3390/pathogens12020214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/21/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Acanthamoeba keratitis is almost universally associated with contact lens (CL) use. Until today, however, CL solution manufacturing protocols lack testing of anti-amoebic activity. This study investigates the effectiveness of CL solutions available on the Dutch market against trophozoites and cysts of Acanthamoeba castellanii and Acanthamoeba polyphaga. Sixteen CL solutions were tested: 13 multiple purpose solutions (MPS), 2 hydrogen peroxidase solutions (HPS) and 1 povidone-iodine-based solution (PIS). The Spearman-Karber (SK) log reduction method and an XTT colorimetric assay were used to evaluate the effectiveness at the manufacturer's minimum recommended disinfection time (MMRDT) and after eight hours. At the MMRDT, one MPS showed an SK mean log reduction (MLR) of >3.0 against A. castellanii trophozoites. Two additional MPS and both HPS reached this threshold after eight hours. The SK MLR values for A. polyphaga trophozoites were between 1 and 3 at all time points. Using the XTT colorimetric assay, only HPS 1 showed >99.9% reduction (equivalent to 3 log reduction) in metabolic activity of A. castellanii trophozoites after eight hours. For A. polyphaga, both HPS and PIS showed a metabolic reduction of >99.9% after eight hours. Cysts were resistant against all solutions. We conclude that following the manufacturer's guidelines, few solutions provide sufficient effectiveness against Acanthamoeba trophozoites and none against cysts. The results underline the importance of adequate hygiene when handling CLs.
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Affiliation(s)
- Anna C. Randag
- Rotterdam Eye Hospital, Schiedamse Vest 180, 3011 BH Rotterdam, The Netherlands
- Rotterdam Ophthalmic Institute, Schiedamse Vest 160, 3011 BH Rotterdam, The Netherlands
- Correspondence:
| | - Lieke de Kroon
- Radboud University Medical Center, Postbus 9101, 6500 HB Nijmegen, The Netherlands
| | - Henny Otten
- Visser Contactlenzen, St. Annastraat 93, 6524 EJ Nijmegen, The Netherlands
| | | | - Barbara Schimmer
- National Institute for Public Health and the Environment (RIVM), Postbus 1, 3720 BA Bilthoven, The Netherlands
| | - Titia Kortbeek
- National Institute for Public Health and the Environment (RIVM), Postbus 1, 3720 BA Bilthoven, The Netherlands
| | - Jeroen van Rooij
- Rotterdam Eye Hospital, Schiedamse Vest 180, 3011 BH Rotterdam, The Netherlands
- Rotterdam Ophthalmic Institute, Schiedamse Vest 160, 3011 BH Rotterdam, The Netherlands
| | - Foekje F. Stelma
- Radboud University Medical Center, Postbus 9101, 6500 HB Nijmegen, The Netherlands
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Fakae LB, Harun MS, Ting DSJ, Dua HS, Cave GW, Zhu XQ, Stevenson CW, Elsheikha HM. Camellia sinensis solvent extract, epigallocatechin gallate and caffeine confer trophocidal and cysticidal effects against Acanthamoeba castellanii. Acta Trop 2023; 237:106729. [DOI: 10.1016/j.actatropica.2022.106729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 11/19/2022]
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Megha K, Sharma M, Sharma C, Gupta A, Sehgal R, Khurana S. Evaluation of in vitro activity of five antimicrobial agents on Acanthamoeba isolates and their toxicity on human corneal epithelium. Eye (Lond) 2022; 36:1911-1917. [PMID: 34548636 PMCID: PMC9500015 DOI: 10.1038/s41433-021-01768-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 08/12/2021] [Accepted: 09/10/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Acanthamoeba keratitis (AK) is an important cause of ocular morbidity in both contact lens wearers and non wearers. Medical management comprises prolonged empiric treatment with multiple drugs, leading to adverse effects and suboptimal cure. The present study evaluated the efficiency and safety of common antimicrobial agents used in treatment of AK. METHODS Six Acanthamoeba isolates (four AK, two water samples) were axenized and subjected to in vitro susceptibility testing against chlorhexidine, pentamidine isethionate, polymyxin B, miltefosine, and fluconazole to check for trophocidal and cysticidal activity. The safety profile was analysed by observing the cytotoxicity of the highest cidal concentration toward human corneal epithelial cell (HCEC) line. RESULTS Chlorhexidine had the lowest cidal concentration against both cysts and trophozoites (range 4.16-25 μg/ml) followed by pentamidine isethionate (range 25-166.7 μg/ml). Both agents were nontoxic to HCEC. Polymyxin B (range 25-200 μg/ml) and fluconazole (range 64-512 μg/ml) had relatively higher minimum inhibitory concentrations (MIC); fluconazole was nontoxic even at 1024 μg/ml, but cytotoxicity was observed at 400 μg/ml with polymyxin B. Miltefosine was not effective against cysts at tested concentrations. A. castellanii were more susceptible to all agents (except pentamidine isethionate) than A. lenticulata. Clinical isolates were less susceptible to polymyxin B and fluconazole than environmental isolates, reverse was true for miltefosine. CONCLUSION Chlorhexidine and pentamidine isethionate were the most effective and safe agents against both trophozoites and cysts forms of our Acanthamoeba isolates. Fluconazole had higher MIC but was nontoxic. Polymyxin B was effective at high MIC but therapeutic dose was found toxic. Miltefosine, at tested concentrations, could not inhibit cysts of Acanthamoeba. Clinical isolates had higher MICs for polymyxin B and fluconazole.
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Affiliation(s)
- Kirti Megha
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Megha Sharma
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Chayan Sharma
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Amit Gupta
- Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rakesh Sehgal
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Sumeeta Khurana
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
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Gu YF, Kong LT. Inhibiting p21-activated kinase (PAK7) enhances radiosensitivity in hepatocellular carcinoma. Hum Exp Toxicol 2021; 40:2202-2214. [PMID: 34165002 DOI: 10.1177/09603271211027948] [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: 11/16/2022]
Abstract
OBJECTIVE In light of the upregulation of p21-activated kinase (PAK7) in a variety of cancers, including hepatocellular carcinoma (HCC), we aimed to investigate the effect of PAK7 on the sensitivity of HCC cells to radiotherapy. METHODS PAK7 expression was determined in normal adult liver epithelial THLE-2 and human HCC cell lines. The effect of ionizing radiation (IR) on the HCC cell viability was evaluated by Sulforhodamine B (SRB) assay. HCC cell lines Mahlavu and Huh7 were chosen to assess the effect of PAK7 shRNAs on the viability, clone formation, apoptosis, cycle distribution and γ-H2AX expression after exposure to IR. RESULTS As compared to THLE-2 cells, PAK7 was upregulated in poorly differentiated Mahlavu and SK-Hep-1 cells, but moderately or lowly expressed in well-differentiated Huh7 and HepG2 cells. HCC cells with moderate or low expression of PAK7 presented a decreased viability at 2 Gy IR, which had no significant effect on PAK7high HCC cells. Mahlavu and Huh7 cells transfected with PAK7 shRNAs showed increased inhibitory effect of IR on viability. In addition, PAK7 shRNAs reduced clone formation, facilitated the cell apoptosis, arrested cells at G2/M phase, and increased γ-H2AX expression. Moreover, changes above were more evident in the HCC cells co-treated with IR and PAK7 shRNAs. CONCLUSION PAK7 downregulation could inhibit the viability, promote the apoptosis, arrest cells in G2/M phase, and induce the DNA damage in HCC cells, thereby enhancing the radiosensitivity in HCC.
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Affiliation(s)
- Y-F Gu
- Department of Radiotherapy Second Ward, YanTaiShan hospital, YanTai, Shandong, People's Republic of China
| | - L-T Kong
- Department of Emergency, YanTaiShan Hospital, YanTai, Shandong, People's Republic of China
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Dickson A, Cooper E, Fakae LB, Wang B, Chan KLA, Elsheikha HM. In Vitro Growth- and Encystation-Inhibitory Efficacies of Matcha Green Tea and Epigallocatechin Gallate Against Acanthameoba Castellanii. Pathogens 2020; 9:pathogens9090763. [PMID: 32957663 PMCID: PMC7558711 DOI: 10.3390/pathogens9090763] [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: 08/17/2020] [Revised: 08/31/2020] [Accepted: 09/09/2020] [Indexed: 11/25/2022] Open
Abstract
We examined the inhibitory effect of matcha green tea (Camellia sinensis) and epigallocatechin gallate (EGCg; the most abundant catechin in tea) on the vegetative growth and encystation of Acanthamoeba castellanii T4 genotype. The sulforhodamine B (SRB) stain-based colorimetric assay and hemocytometer counting were used to determine the reduction in A. castellanii trophozoite proliferation and encystation, in response to treatment with C. sinensis or EGCg. Fourier transform infrared (FTIR) microscopy was used to analyze chemical changes in the trophozoites and cysts due to C. sinensis treatment. Hot brewed and cold brewed matcha inhibited the growth of trophozoites by >40% at a 100 % concentration. EGCg at concentrations of 50 to 500 µM significantly inhibited the trophozoite growth compared to control. Hot brewed matcha (100% concentration) also showed an 87% reduction in the rate of encystation compared to untreated control. Although 500 µM of EGCg increased the rate of encystation by 36.3%, 1000 µM reduced it by 27.7%. Both percentages were not significant compared to control. C. sinensis induced more cytotoxicity to Madin Darby canine kidney cells compared to EGCg. FTIR chemical fingerprinting analysis showed that treatment with brewed matcha significantly increased the levels of glycogen and carbohydrate in trophozoites and cysts.
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Affiliation(s)
- Ameliya Dickson
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Elise Cooper
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Lenu B. Fakae
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Bo Wang
- School of Mathematics and Actuarial Science, University of Leicester, Leicester LE1 7RH, UK;
| | - Ka Lung Andrew Chan
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, UK;
| | - Hany M. Elsheikha
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
- Correspondence: ; Tel.: +44-0115-951-6445
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Helal MA, Abdel-Gawad AM, Kandil OM, Khalifa MME, Cave GWV, Morrison AA, Bartley DJ, Elsheikha HM. Nematocidal Effects of a Coriander Essential Oil and Five Pure Principles on the Infective Larvae of Major Ovine Gastrointestinal Nematodes In Vitro. Pathogens 2020; 9:E740. [PMID: 32916863 PMCID: PMC7558654 DOI: 10.3390/pathogens9090740] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/05/2020] [Accepted: 09/07/2020] [Indexed: 12/22/2022] Open
Abstract
The anthelmintic effects of extracted coriander oil and five pure essential oil constituents (geraniol, geranyl acetate, eugenol, methyl iso-eugenol, and linalool) were tested, using larval motility assay, on the third-stage larvae (L3s) of Haemonchus contortus, Trichostrongylus axei, Teladorsagia circumcincta, Trichostrongylus colubriformis, Trichostrongylus vitrinus and Cooperia oncophora. Coriander oil and linalool, a major component of tested coriander oil, showed a strong inhibitory efficacy against all species, except C. oncophora with a half maximal inhibitory concentration (IC50) that ranged from 0.56 to 1.41% for the coriander oil and 0.51 to 1.76% for linalool. The coriander oil and linalool combinations conferred a synergistic anthelmintic effect (combination index [CI] <1) on larval motility comparable to positive control (20 mg/mL levamisole) within 24 h (p < 0.05), reduced IC50 values to 0.11-0.49% and induced a considerable structural damage to L3s. Results of the combined treatment were validated by quantitative fluorometric microplate-based assays using Sytox green, propidium iodide and C12-resazurin, which successfully discriminated live/dead larvae. Only Sytox green staining achieved IC50 values comparable to that of the larval motility assay. The cytotoxicity of the combined coriander oil and linalool on Madin-Darby Canine Kidney cells was evaluated using sulforhodamine-B (SRB) assay and showed no significant cytotoxic effect at concentrations < 1%. These results indicate that testing essential oils and their main components may help to find new potential anthelmintic compounds, while at the same time reducing the reliance on synthetic anthelmintics.
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Affiliation(s)
- Mohamed A. Helal
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Leicestershire LE12 5RD, UK;
- Department of Parasitology and Animal Diseases, Veterinary Research Division, National Research Centre, Giza 12622, Egypt;
| | - Ahmed M. Abdel-Gawad
- Parasitology Department, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt; (A.M.A.-G.); (M.M.E.K.)
| | - Omnia M. Kandil
- Department of Parasitology and Animal Diseases, Veterinary Research Division, National Research Centre, Giza 12622, Egypt;
| | - Marwa M. E. Khalifa
- Parasitology Department, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt; (A.M.A.-G.); (M.M.E.K.)
| | - Gareth W. V. Cave
- School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK;
| | - Alison A. Morrison
- Disease Control, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, Edinburgh, UK; (A.A.M.); (D.J.B.)
| | - David J. Bartley
- Disease Control, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, Edinburgh, UK; (A.A.M.); (D.J.B.)
| | - Hany M. Elsheikha
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Leicestershire LE12 5RD, UK;
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Fakae LB, Stevenson CW, Zhu XQ, Elsheikha HM. In vitro activity of Camellia sinensis (green tea) against trophozoites and cysts of Acanthamoeba castellanii. Int J Parasitol Drugs Drug Resist 2020; 13:59-72. [PMID: 32512260 PMCID: PMC7281304 DOI: 10.1016/j.ijpddr.2020.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 01/06/2023]
Abstract
The effect of Camellia sinensis (green tea) on the growth of Acanthamoeba castellanii trophozoites was examined using a microplate based-Sulforhodamine B (SRB) assay. C. sinensis hot and cold brews at 75% and 100% concentrations significantly inhibited the growth of trophozoites. We also examined the structural alterations in C. sinensis-treated trophozoites using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). This analysis showed that C. sinensis compromised the cell membrane integrity and caused progressive destruction of trophozoites. C. sinensis also significantly inhibited the parasite's ability to form cysts in a dose-dependent manner and reduced the rate of excystation from cysts to trophozoites. C. sinensis exhibited low cytotoxic effects on primary corneal stromal cells. However, cytotoxicity was more pronounced in SV40-immortalized corneal epithelial cells. Chromatographic analysis showed that both hot and cold C. sinensis brews contained the same number and type of chemical compounds. This work demonstrated that C. sinensis has anti-acanthamoebic activity against trophozoite and cystic forms of A. castellanii. Further studies are warranted to identify the exact substances in C. sinensis that have the most potent anti-acanthamoebic effect.
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Affiliation(s)
- Lenu B Fakae
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK; School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK; Rivers State University, Nkpolu - Oroworukwo P.M.B 5080, Port Harcourt, Rivers State, Nigeria
| | - Carl W Stevenson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Hany M Elsheikha
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
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Anwar A, Soomaroo A, Anwar A, Siddiqui R, Khan NA. Metformin-coated silver nanoparticles exhibit anti-acanthamoebic activities against both trophozoite and cyst stages. Exp Parasitol 2020; 215:107915. [PMID: 32461112 DOI: 10.1016/j.exppara.2020.107915] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 05/07/2020] [Accepted: 05/11/2020] [Indexed: 12/20/2022]
Abstract
Acanthamoeba castellanii is an opportunistic protozoan responsible for serious human infections including Acanthamoeba keratitis and granulomatous amoebic encephalitis. Despite advances in antimicrobial therapy and supportive care, infections due to Acanthamoeba are a major public concern. Current methods of treatment are not fully effective against both the trophozoite and cyst forms of A. castellanii and are often associated with severe adverse effects, host cell cytotoxicity and recurrence of infection. Therefore, there is an urgent need to develop new therapeutic approaches for the treatment and management of Acanthamoebic infections. Repurposing of clinically approved drugs is a viable avenue for exploration and is particularly useful for neglected and rare diseases where there is limited interest by pharmaceutical companies. Nanotechnology-based drug delivery systems offer promising approaches in the biomedical field, particularly in diagnosis and drug delivery. Herein, we conjugated an antihyperglycemic drug, metformin with silver nanoparticles and assessed its anti-acanthamoebic properties. Characterization by ultraviolet-visible spectrophotometry and atomic force microscopy showed successful formation of metformin-coated silver nanoparticles. Amoebicidal and amoebistatic assays revealed that metformin-coated silver nanoparticles reduced the viability and inhibited the growth of A. castellanii significantly more than metformin and silver nanoparticles alone at both 5 and 10 μM after 24 h incubation. Metformin-coated silver nanoparticles also blocked encystation and inhibited the excystation in Acanthamoeba after 72 h incubation. Overall, the conjugation of metformin with silver nanoparticles was found to enhance its antiamoebic effects against A. castellanii. Furthermore, the pretreatment of A. castellanii with metformin and metformin-coated silver nanoparticles for 2 h also reduced the amoebae-mediated host cell cytotoxicity after 24 h incubation from 73% to 10% at 10 μM, indicating that the drug-conjugated silver nanoparticles confer protection to human cells. These findings suggest that metformin-coated silver nanoparticles hold promise in the improved treatment and management of Acanthamoeba infections.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia.
| | - Akshinee Soomaroo
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Areeba Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, Sharjah, 26666, United Arab Emirates
| | - Naveed Ahmed Khan
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, Sharjah, 26666, United Arab Emirates
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The Antifungal Drug Isavuconazole Is both Amebicidal and Cysticidal against Acanthamoeba castellanii. Antimicrob Agents Chemother 2020; 64:AAC.02223-19. [PMID: 32094126 DOI: 10.1128/aac.02223-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/17/2020] [Indexed: 11/20/2022] Open
Abstract
Current treatments for Acanthamoeba keratitis rely on a combination of chlorhexidine gluconate, propamidine isethionate, and polyhexamethylene biguanide. These disinfectants are nonspecific and inherently toxic, which limits their effectiveness. Furthermore, in 10% of cases, recurrent infection ensues due to the difficulty in killing both trophozoites and double-walled cysts. Therefore, development of efficient, safe, and target-specific drugs which are capable of preventing recurrent Acanthamoeba infection is a critical unmet need for averting blindness. Since both trophozoites and cysts contain specific sets of membrane sterols, we hypothesized that antifungal drugs targeting sterol 14-demethylase (CYP51), known as conazoles, would have deleterious effects on A. castellanii trophozoites and cysts. To test this hypothesis, we first performed a systematic screen of the FDA-approved conazoles against A. castellanii trophozoites using a bioluminescence-based viability assay adapted and optimized for Acanthamoeba The most potent drugs were then evaluated against cysts. Isavuconazole and posaconazole demonstrated low nanomolar potency against trophozoites of three clinical strains of A. castellanii Furthermore, isavuconazole killed trophozoites within 24 h and suppressed excystment of preformed Acanthamoeba cysts into trophozoites. The rapid action of isavuconazole was also evident from the morphological changes at nanomolar drug concentrations causing rounding of trophozoites within 24 h of exposure. Given that isavuconazole has an excellent safety profile, is well tolerated in humans, and blocks A. castellanii excystation, this opens an opportunity for the cost-effective repurposing of isavuconazole for the treatment of primary and recurring Acanthamoeba keratitis.
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Anaerobic Metabolism in T4 Acanthamoeba Genotype. Curr Microbiol 2017; 74:685-690. [PMID: 28326448 DOI: 10.1007/s00284-017-1223-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/23/2017] [Indexed: 12/31/2022]
Abstract
Members of the genus Acanthamoeba are of the most common protozoa that has been isolated from a variety of environment and affect immunocompromised individuals, causing granulomatous amoebic encephalitis and skin lesions. Acanthamoeba, in immunocompetent patients, may cause a keratitis related to corneal microtrauma. These free-living amoebas easily adapt to the host environment and wield metabolic pathways such as the energetic and respiratory ones in order to maintain viability for long periods. The energetic metabolism of cysts and trophozoites remains mostly unknown. There are a few reports on the energetic metabolism of these organisms as they are mitochondriate eukaryotes and some studies under aerobic conditions showing that Acanthamoeba hydrolyzes glucose into pyruvate via glycolysis. The aim of this study was to detect the energetic metabolic pathways with emphasis on anaerobic metabolism in trophozoites of three isolates of Acanthamoeba sp belonging to the T4 genotype. Two samples were collected in the environment and one was a clinical sample. The evaluation of these microorganisms proceeded as follows: rupture of trophozoites (7.5 × 103 parasites/ml) and biochemical analysis with high performance liquid chromatography and spectrophotometry. The anaerobic glycolysis was identified through the detection of glucose, pyruvate, and lactate. The protein catabolism was identified through the detection of fumarate, urea, and creatinine. The fatty acid oxidation was identified through the detection of acetate, beta-hydroxybutyrate, and propionate. The detected substances are the result of the consumption of energy reserves such as glycogen and lipids. The anaerobic glycolysis and protein catabolism pathways were observed in all three isolates: one clinical and two environmental. This study represents the first report of energetic pathways used by trophozoites from different isolates of the T4 genotype Acanthamoeba.
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