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Messina M, Tucci D, Mocini S, Marruso V, Crotti S, Said D, Dua HS, Cagini C. Increasing incidence of contact-lens-related Acanthamoeba keratitis in a tertiary ophthalmology department in an Italian population. Eur J Ophthalmol 2024:11206721241242165. [PMID: 38509758 DOI: 10.1177/11206721241242165] [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: 03/22/2024]
Abstract
PURPOSE The purpose of this paper is to report the increasing incidence of contact-lens related Acanthamoeba keratitis (AK) in a tertiary ophthalmology department in Umbria, central Italy. METHODS Observational and retrospective case series were carried out. A total of nine eyes with a diagnosis of AK were examined. All patients underwent a full slit lamp examination, in vivo confocal microscopy (IVCM) and corneal scraping. The IVCM was repeated at one and two-week and at one, three and six-month intervals. Samples of domestic tap water were also examined for PCR analysis. Patients were treated with levofloxacin0,5%, Polyhexamethylene biguanide 0.02%, and Propamidine Isetionate0,1%. RESULTS All patients were contact lens wearers. The average patient age was 27.75 (range 18-45), with three men and five women. The main clinical features were ciliary congestion, diffuse epitheliopathy with punctuated keratitis, multiple, small sub-epithelial, greyish, corneal infiltrates with epithelial defect, pseudodendritic corneal lesions, perineural infiltrates, corneal stromal cellularity, and stromal infiltrates. IVCM was indicative of Acanthamoeba in seven out of the nine eyes. All the positive IVCM images were section images showing double walled, bright-spot cysts with a clear chain-like arrangement of five or more cysts identified in three of the patients. PCR analysis of the water was negative in all cases. CONCLUSION Although PCR is the most common method used, the increased incidence of AK could mainly be related to a proper IVCM interpretation. A broad-spectrum antibiotic, such as levofloxacin might play a role in the early treatment of AK reducing the virulence of the amoeba.
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Affiliation(s)
- Marco Messina
- Department of Medicine and Surgery, Section of Ophthalmology, University of Perugia, S. Maria Della Misericordia Hospital, Perugia, Italy
| | - Davide Tucci
- Department of Medicine and Surgery, Section of Ophthalmology, University of Perugia, S. Maria Della Misericordia Hospital, Perugia, Italy
| | - Stefano Mocini
- Department of Medicine and Surgery, Section of Ophthalmology, University of Perugia, S. Maria Della Misericordia Hospital, Perugia, Italy
| | - Virginia Marruso
- Department of Medicine and Surgery, Section of Ophthalmology, University of Perugia, S. Maria Della Misericordia Hospital, Perugia, Italy
| | - Silvia Crotti
- Diagnostic Laboratory, Sperimental Zooprophylactic Institute of Umbria and Marche "Togo Rosati", Perugia, Italy
| | - Dalia Said
- Department of Ophthalmology, Section of Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Harminder Singh Dua
- Department of Ophthalmology, Section of Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Carlo Cagini
- Department of Medicine and Surgery, Section of Ophthalmology, University of Perugia, S. Maria Della Misericordia Hospital, Perugia, Italy
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Alishba, Ahmed U, Taha M, Khan NA, Salar U, Khan KM, Anwar A, Siddiqui R. Potential anti-amoebic effects of synthetic 1,4-benzothiazine derivatives against Acanthamoeba castellanii. Heliyon 2024; 10:e23258. [PMID: 38205285 PMCID: PMC10776951 DOI: 10.1016/j.heliyon.2023.e23258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 11/29/2023] [Accepted: 11/29/2023] [Indexed: 01/12/2024] Open
Abstract
A rare but lethal central nervous system disease known as granulomatous amoebic encephalitis (GAE) and potentially blinding Acanthamoeba keratitis are diseases caused by free-living Acanthamoeba. Currently, no therapeutic agent can completely eradicate or prevent GAE. Synthetic compounds are a likely source of bioactive compounds for developing new drugs. This study synthesized seventeen 1,4-benzothiazine derivatives (I -XVII) by a base-catalyzed one-pot reaction of 2-amino thiophenol with substituted bromo acetophenones. Different spectroscopic techniques, such as EI-MS, 1H-, and 13C NMR (only for the new compounds), were used for the structural characterization and conformation of compounds. These compounds were assessed for the first time against Acanthamoeba castellanii. All compounds showed anti-amoebic potential in vitro against A. castellanii, reducing its ability to encyst and excyst at 100 μM. Compounds IX, X, and XVI showed the most potent activities among all derivatives and significantly reduced the viability to 5.3 × 104 (p < 0.0003), 2 × 105 (p < 0.006), and 2.4 × 105 (p < 0.002) cells/mL, respectively. The cytotoxicity profile revealed that these molecules showed lower to moderate cytotoxicity, i.e., 36 %, 2 %, and 21 %, respectively, against human keratinocytes in vitro. These results indicate that 1,4-benzothiazines showed potent in vitro activity against trophozoites and cysts of A. castellanii. Hence, these 1,4-benzothiazine derivatives should be considered to develop new potential therapeutic agents against Acanthamoeba infections.
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Affiliation(s)
- Alishba
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Usman Ahmed
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Muhammad Taha
- Department of Clinical Pharmacy, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | | | - Uzma Salar
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Khalid Mohammed Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
- Department of Clinical Pharmacy, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
- Pakistan Academy of Sciences, 3-Constitution Avenue G-5/2, Islamabad, Pakistan
| | - Ayaz Anwar
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, Sharjah, United Arab Emirates
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Ahmed U, Manzoor M, Qureshi S, Mazhar M, Fatima A, Aurangzeb S, Hamid M, Khan KM, Khan NA, Rashid Y, Anwar A. Anti-amoebic effects of synthetic acridine-9(10H)-one against brain-eating amoebae. Acta Trop 2023; 239:106824. [PMID: 36610529 DOI: 10.1016/j.actatropica.2023.106824] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/30/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Abstract
Pathogenic A. castellanii and N. fowleri are opportunistic free-living amoebae. Acanthamoeba spp. are the causative agents of granulomatous amebic encephalitis (GAE) and amebic keratitis (AK), whereas Naegleria fowleri causes a very rare but severe brain infection called primary amebic meningoencephalitis (PAM). Acridinone is an important heterocyclic scaffold and both synthetic and naturally occurring derivatives have shown various valuable biological properties. In the present study, ten synthetic Acridinone derivatives (I-X) were synthesized and assessed against both amoebae for anti-amoebic and cysticidal activities in vitro. In addition, excystation, encystation, cytotoxicity, host cell pathogenicity was also performed in-vitro. Furthermore, molecular docking studies of these compounds with three cathepsin B paralogous enzymes of N. fowleri were performed in order to predict the possible docking mode with pathogen. Compound VII showed potent anti-amoebic activity against A. castellanii with IC50 53.46 µg/mL, while compound IX showed strong activity against N. fowleri in vitro with IC50 72.41 µg/mL. Compounds II and VII showed a significant inhibition of phenotypic alteration of A. castellanii, while compound VIII significantly inhibited N. fowleri cysts. Cytotoxicity assessment showed that these compounds caused minimum damage to human keratinocyte cells (HaCaT cells) at 100 µg/mL, while also effectively reduced the cytopathogenicity of Acanthamoeba to HaCaT cells. Moreover, Cathepsin B protease was investigated in-silico as a new molecular therapeutic target for these compounds. All compounds showed potential interactions with the catalytic residues. These results showed that acridine-9(10H)-one derivatives, in particular compounds II, VII, VIII and IX hold promise in the development of therapeutic agents against these free-living amoebae.
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Affiliation(s)
- Usman Ahmed
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Mehwish Manzoor
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Sehrish Qureshi
- Department of Biochemistry, University of Karachi, Karachi, Pakistan
| | - Muzna Mazhar
- Department of Biochemistry, University of Karachi, Karachi, Pakistan
| | - Arj Fatima
- Department of Biochemistry, University of Karachi, Karachi, Pakistan
| | - Sana Aurangzeb
- Department of Biochemistry, University of Karachi, Karachi, Pakistan
| | - Mehwish Hamid
- Department of Biochemistry, University of Karachi, Karachi, Pakistan
| | - Khalid Mohammed Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan; Department of Clinical Pharmacy, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, University City, United Arab Emirates; Department of Medical Biology, Faculty of Medicine, Istinye University, Istanbul, 34010, Turkey
| | - Yasmeen Rashid
- Department of Biochemistry, University of Karachi, Karachi, Pakistan.
| | - Ayaz Anwar
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia.
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Cabrera‐Aguas M, Khoo P, Watson SL. Infectious keratitis: A review. Clin Exp Ophthalmol 2022; 50:543-562. [PMID: 35610943 PMCID: PMC9542356 DOI: 10.1111/ceo.14113] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 12/29/2022]
Abstract
Globally, infectious keratitis is the fifth leading cause of blindness. The main predisposing factors include contact lens wear, ocular injury and ocular surface disease. Staphylococcus species, Pseudomonas aeruginosa, Fusarium species, Candida species and Acanthamoeba species are the most common causal organisms. Culture of corneal scrapes is the preferred initial test to identify the culprit organism. Polymerase chain reaction (PCR) tests and in vivo confocal microscopy can complement the diagnosis. Empiric therapy is typically commenced with fluoroquinolones, or fortified antibiotics for bacterial keratitis; topical natamycin for fungal keratitis; and polyhexamethylene biguanide or chlorhexidine for acanthamoeba keratitis. Herpes simplex keratitis is mainly diagnosed clinically; however, PCR can also be used to confirm the initial diagnosis and in atypical cases. Antivirals and topical corticosteroids are indicated depending on the corneal layer infected. Vision impairment, blindness and even loss of the eye can occur with a delay in diagnosis and inappropriate antimicrobial therapy.
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Affiliation(s)
- Maria Cabrera‐Aguas
- Save Sight Institute, Discipline of Ophthalmology, Faculty of Medicine and Health The University of Sydney Sydney New South Wales Australia
- Corneal Unit Sydney Eye Hospital Sydney New South Wales Australia
| | - Pauline Khoo
- Save Sight Institute, Discipline of Ophthalmology, Faculty of Medicine and Health The University of Sydney Sydney New South Wales Australia
- Corneal Unit Sydney Eye Hospital Sydney New South Wales Australia
| | - Stephanie L. Watson
- Save Sight Institute, Discipline of Ophthalmology, Faculty of Medicine and Health The University of Sydney Sydney New South Wales Australia
- Corneal Unit Sydney Eye Hospital Sydney New South Wales Australia
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Kennedy SM, Deshpande P, Gallagher AG, Horsburgh MJ, Allison HE, Kaye SB, Wellings DA, Williams RL. Amoebicidal Activity of Poly-Epsilon-Lysine Functionalized Hydrogels. Invest Ophthalmol Vis Sci 2022; 63:11. [PMID: 34994769 PMCID: PMC8742527 DOI: 10.1167/iovs.63.1.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine the amoebicidal activity of functionalized poly-epsilon-lysine hydrogels (pɛK+) against Acanthamoeba castellanii. Methods A. castellanii trophozoites and cysts were grown in the presence of pɛK solution (0–2.17 mM), pɛK or pɛK+ hydrogels, or commercial hydrogel contact lens (CL) for 24 hours or 7 days in PBS or Peptone-Yeast-Glucose (PYG) media (nutrient-deplete or nutrient-replete cultures, respectively). Toxicity was determined using propidium iodide and imaged using fluorescence microscopy. Ex vivo porcine corneas were inoculated with A. castellanii trophozoites ± pɛK, pɛK+ hydrogels or commercial hydrogel CL for 7 days. Corneal infection was assessed by periodic acid–Schiff staining and histologic analysis. Regrowth of A. castellanii from hydrogel lenses and corneal discs at 7 days was assessed using microscopy and enumeration. Results The toxicity of pɛK+ hydrogels resulted in the death of 98.52% or 83.31% of the trophozoites at 24 hours or 7 days, respectively. The toxicity of pɛK+ hydrogels resulted in the death of 70.59% or 82.32% of the cysts in PBS at 24 hours or 7 days, respectively. Cysts exposed to pɛK+ hydrogels in PYG medium resulted in 75.37% and 87.14% death at 24 hours and 7 days. Ex vivo corneas infected with trophozoites and incubated with pɛK+ hydrogels showed the absence of A. castellanii in the stroma, with no regrowth from corneas or pɛK+ hydrogel, compared with infected-only corneas and those incubated in presence of commercial hydrogel CL. Conclusions pɛK+ hydrogels demonstrated pronounced amoebicidal and cysticidal activity against A. castellanii. pɛK+ hydrogels have the potential for use as CLs that could minimize the risk of CL-associated Acanthamoeba keratitis.
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Affiliation(s)
- Stephnie M Kennedy
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Pallavi Deshpande
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Andrew G Gallagher
- SpheriTech Ltd, The Heath Business and Technical Park, Runcorn, Cheshire, United Kingdom
| | - Malcolm J Horsburgh
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Heather E Allison
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Stephen B Kaye
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Donald A Wellings
- SpheriTech Ltd, The Heath Business and Technical Park, Runcorn, Cheshire, United Kingdom
| | - Rachel L Williams
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
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Sharma G, Kalra SK, Tejan N, Ghoshal U. Nanoparticles based therapeutic efficacy against Acanthamoeba: Updates and future prospect. Exp Parasitol 2020; 218:108008. [PMID: 32979343 DOI: 10.1016/j.exppara.2020.108008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/17/2020] [Accepted: 09/23/2020] [Indexed: 12/15/2022]
Abstract
Acanthamoeba sp. is a free living amoeba that causes severe, painful and fatal infections, viz. Acanthamoeba keratitis and granulomatous amoebic encephalitis among humans. Antimicrobial chemotherapy used against Acanthamoeba is toxic to human cells and show side effects as well. Infections due to Acanthamoeba also pose challenges towards currently used antimicrobial treatment including resistance and transformation of trophozoites to resistant cyst forms that can lead to recurrence of infection. Therapeutic agents targeting central nervous system infections caused by Acanthamoeba should be able to cross blood-brain barrier. Nanoparticles based drug delivery put forth an effective therapeutic method to overcome the limitations of currently used antimicrobial chemotherapy. In recent years, various researchers investigated the effectiveness of nanoparticles conjugated drug and/or naturally occurring plant compounds against both trophozoites and cyst form of Acanthamoeba. In the current review, a reasonable effort has been made to provide a comprehensive overview of various nanoparticles tested for their efficacy against Acanthamoeba. This review summarizes the noteworthy details of research performed to elucidate the effect of nanoparticles conjugated drugs against Acanthamoeba.
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Affiliation(s)
- Geetansh Sharma
- Faculty of Applied Sciences & Biotechnology, Shoolini University of Biotechnology & Management Sciences, Bajhol, District Solan, H.P, 173229, India
| | - Sonali K Kalra
- Faculty of Applied Sciences & Biotechnology, Shoolini University of Biotechnology & Management Sciences, Bajhol, District Solan, H.P, 173229, India.
| | - Nidhi Tejan
- Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareili Road, Lucknow, U.P, 226014, India
| | - Ujjala Ghoshal
- Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareili Road, Lucknow, U.P, 226014, India
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Drug Discovery against Acanthamoeba Infections: Present Knowledge and Unmet Needs. Pathogens 2020; 9:pathogens9050405. [PMID: 32456110 PMCID: PMC7281112 DOI: 10.3390/pathogens9050405] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/12/2022] Open
Abstract
Although major strides have been made in developing and testing various anti-acanthamoebic drugs, recurrent infections, inadequate treatment outcomes, health complications, and side effects associated with the use of currently available drugs necessitate the development of more effective and safe therapeutic regimens. For any new anti-acanthamoebic drugs to be more effective, they must have either superior potency and safety or at least comparable potency and an improved safety profile compared to the existing drugs. The development of the so-called 'next-generation' anti-acanthamoebic agents to address this challenge is an active area of research. Here, we review the current status of anti-acanthamoebic drugs and discuss recent progress in identifying novel pharmacological targets and new approaches, such as drug repurposing, development of small interfering RNA (siRNA)-based therapies and testing natural products and their derivatives. Some of the discussed approaches have the potential to change the therapeutic landscape of Acanthamoeba infections.
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Alkyl-carbon chain length of two distinct compounds and derivatives are key determinants of their anti-Acanthamoeba activities. Sci Rep 2020; 10:6420. [PMID: 32286337 PMCID: PMC7156471 DOI: 10.1038/s41598-020-62934-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 03/05/2020] [Indexed: 02/06/2023] Open
Abstract
The opportunistic pathogen, Acanthamoeba castellanii is the causative agent for the sight threatening infection Acanthamoeba keratitis (AK). It is commonly associated with contact lens wearers, and prevalence is increasing at an alarming rate due to an inadequate preventive strategy to protect the lens from this protist. This problem is compounded by the lack of an effective acanthamoebocide, particularly with cysticidal activity in the contact lens solutions. We have used cytotoxicity assays and a variety of biophysical approaches to show that two molecules with tails made of alkyl carbon, alkylphosphocholines (APCs) and quaternary ammonium compounds (QACs) had significant chain-length dependent efficacy against A. castellanii trophozoites, the latter producing death via permeabilization, and DNA complexing. QACs were more effective than APCs and had activity against cysts. Conversely, the QAC with 12 alkyl carbon chain, was non toxic, its presence increased A. castellanii trophozoites biomass and delayed encystation by 96 h. Interestingly, it was unable to induce excystation and increased trophozoite sensitivity to APC16. These results present a mono- and multi-inhibitor management strategy effective against trophozoites and cysts that may be useful for formulating into contact lense cleaning solutions and reducing AK incidence.
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Garajová M, Mrva M, Vaškovicová N, Martinka M, Melicherová J, Valigurová A. Cellulose fibrils formation and organisation of cytoskeleton during encystment are essential for Acanthamoeba cyst wall architecture. Sci Rep 2019; 9:4466. [PMID: 30872791 PMCID: PMC6418277 DOI: 10.1038/s41598-019-41084-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 03/01/2019] [Indexed: 01/26/2023] Open
Abstract
Acanthamoebae success as human pathogens is largely due to the highly resistant cysts which represent a crucial problem in treatment of Acanthamoeba infections. Hence, the study of cyst wall composition and encystment play an important role in finding new therapeutic strategies. For the first time, we detected high activity of cytoskeletal elements - microtubular networks and filamentous actin, in late phases of encystment. Cellulose fibrils - the main components of endocyst were demonstrated in inter-cystic space, and finally in the ectocyst, hereby proving the presence of cellulose in both layers of the cyst wall. We detected clustering of intramembranous particles (IMPs) and their density alterations in cytoplasmic membrane during encystment. We propose a hypothesis that in the phase of endocyst formation, the IMP clusters represent cellulose microfibril terminal complexes involved in cellulose synthesis that after cyst wall completion are reduced. Cyst wall impermeability, due largely to a complex polysaccharide (glycans, mainly cellulose) has been shown to be responsible for Acanthamoeba biocide resistance and cellulose biosynthesis pathway is suggested to be a potential target in treatment of Acanthamoeba infections. Disruption of this pathway would affect the synthesis of cyst wall and reduce considerably the resistance to chemotherapeutic agents.
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Affiliation(s)
- Mária Garajová
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic.
| | - Martin Mrva
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic
| | - Naděžda Vaškovicová
- Institute of Scientific Instruments, Czech Academy of Sciences, 612 64, Brno, Czech Republic
| | - Michal Martinka
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic
| | - Janka Melicherová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, 611 37, Brno, Czech Republic
| | - Andrea Valigurová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, 611 37, Brno, Czech Republic
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Abstract
In recent years, Acanthamoeba keratitis (AK) has became a clinically significant problem because of the broad use of contact lenses that are the major risk factor of the disease. The treatment presents considerable difficulties due to similarity of clinical manifestations of AK to other keratites (bacterial, herpetic, and fungal). This often leads to late diagnosis and formation of drug-resistant cysts. There is currently no specific drug universally suitable for monotherapy of AK. Instead, 2 agents (usually chlorhexidine and poligexametilen biguanide) are used that, if combined, are effective against both trophozoites and cysts. If necessary (severe keratitis, insufficient treatment effect), diamidines (propamidine and its analogs), antifungals (fluconazole, itrakonazol), certain antibiotics (Neomycinum), and iodine-containing medications (povidone-iodine) can be prescribed. The use of corticosteroids is considered unjustified because of the risk of rapid progression (due to disturbance of local immunity and also provocation of excystation of the amoebas). The penetrative keratoplasty may be required, especially if a descemetocele or corneal perforation occurs, however, its results are generally worse than those in other keratites because of a higher risk of complications (iridocyclitis, secondary glaucoma, AK recurrence in the graft). In some cases, good results are achieved with minimally invasive surgeries, such as mechanical epithelial debridement, conjunctivoplasty and cryopreserved amniotic membrane transplantation, excimer laser phototherapeutic keratectomy, and cross-linking. In the future, gene therapy and specific chemotherapy of AK may well be developed.
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Affiliation(s)
- N R Marchenko
- Research Institute of Eye Diseases, 11A, B Rossolimo St., Moscow, Russian Federation, 119021
| | - Evg A Kasparova
- Research Institute of Eye Diseases, 11A, B Rossolimo St., Moscow, Russian Federation, 119021
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Lorenzo-Morales J, Reyes-Batlle M, Sifaoui I, Arnalich-Montiel F, López-Arencibia A, Wagner C, Rocha-Cabrera P, del Castillo-Remiro A, Martínez-Carretero E, Piñero JE, Valladares B. Therapeutic targets and investigated treatment strategies inAcanthamoebakeratitis. Expert Opin Orphan Drugs 2016. [DOI: 10.1080/21678707.2016.1230060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lorenzo-Morales J, Khan NA, Walochnik J. An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment. ACTA ACUST UNITED AC 2015; 22:10. [PMID: 25687209 PMCID: PMC4330640 DOI: 10.1051/parasite/2015010] [Citation(s) in RCA: 427] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/06/2015] [Indexed: 12/21/2022]
Abstract
Free-living amoebae of the genus Acanthamoeba are causal agents of a severe sight-threatening infection of the cornea known as Acanthamoeba keratitis. Moreover, the number of reported cases worldwide is increasing year after year, mostly in contact lens wearers, although cases have also been reported in non-contact lens wearers. Interestingly, Acanthamoeba keratitis has remained significant, despite our advances in antimicrobial chemotherapy and supportive care. In part, this is due to an incomplete understanding of the pathogenesis and pathophysiology of the disease, diagnostic delays and problems associated with chemotherapeutic interventions. In view of the devastating nature of this disease, here we present our current understanding of Acanthamoeba keratitis and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be potential targets for improved diagnosis, therapeutic interventions and/or for the development of preventative measures. Novel molecular approaches such as proteomics, RNAi and a consensus in the diagnostic approaches for a suspected case of Acanthamoeba keratitis are proposed and reviewed based on data which have been compiled after years of working on this amoebic organism using many different techniques and listening to many experts in this field at conferences, workshops and international meetings. Altogether, this review may serve as the milestone for developing an effective solution for the prevention, control and treatment of Acanthamoeba infections.
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Affiliation(s)
- Jacob Lorenzo-Morales
- University Institute of Tropical Diseases and Public Health of the Canary Islands, University of La Laguna, Avda. Astrofísico Fco. Sánchez, S/N, 38203 La Laguna, Tenerife, Canary Islands, Spain
| | - Naveed A Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Julia Walochnik
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
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Lakhundi S, Siddiqui R, Khan NA. Cellulose degradation: a therapeutic strategy in the improved treatment of Acanthamoeba infections. Parasit Vectors 2015; 8:23. [PMID: 25586209 PMCID: PMC4300153 DOI: 10.1186/s13071-015-0642-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/05/2015] [Indexed: 11/10/2022] Open
Abstract
Acanthamoeba is an opportunistic free-living amoeba that can cause blinding keratitis and fatal brain infection. Early diagnosis, followed by aggressive treatment is a pre-requisite in the successful treatment but even then the prognosis remains poor. A major drawback during the course of treatment is the ability of the amoeba to enclose itself within a shell (a process known as encystment), making it resistant to chemotherapeutic agents. As the cyst wall is partly made of cellulose, thus cellulose degradation offers a potential therapeutic strategy in the effective targeting of trophozoite encased within the cyst walls. Here, we present a comprehensive report on the structure of cellulose and cellulases, as well as known cellulose degradation mechanisms with an eye to target the Acanthamoeba cyst wall. The disruption of the cyst wall will make amoeba (concealed within) susceptible to chemotherapeutic agents, and at the very least inhibition of the excystment process will impede infection recurrence, as we bring these promising drug targets into focus so that they can be explored to their fullest.
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Affiliation(s)
- Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
| | - Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
| | - Naveed Ahmed Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
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Cytomorphological changes and susceptibility of clinical isolates of Acanthamoeba spp. to heterocyclic alkylphosphocholines. Exp Parasitol 2014; 145 Suppl:S102-10. [DOI: 10.1016/j.exppara.2014.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 05/14/2014] [Accepted: 05/26/2014] [Indexed: 11/21/2022]
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16
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Maguire F, Henriquez FL, Leonard G, Dacks JB, Brown MW, Richards TA. Complex patterns of gene fission in the eukaryotic folate biosynthesis pathway. Genome Biol Evol 2014; 6:2709-20. [PMID: 25252772 PMCID: PMC4224340 DOI: 10.1093/gbe/evu213] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Shared derived genomic characters can be useful for polarizing phylogenetic relationships, for example, gene fusions have been used to identify deep-branching relationships in the eukaryotes. Here, we report the evolutionary analysis of a three-gene fusion of folB, folK, and folP, which encode enzymes that catalyze consecutive steps in de novo folate biosynthesis. The folK-folP fusion was found across the eukaryotes and a sparse collection of prokaryotes. This suggests an ancient derivation with a number of gene losses in the eukaryotes potentially as a consequence of adaptation to heterotrophic lifestyles. In contrast, the folB-folK-folP gene is specific to a mosaic collection of Amorphea taxa (a group encompassing: Amoebozoa, Apusomonadida, Breviatea, and Opisthokonta). Next, we investigated the stability of this character. We identified numerous gene losses and a total of nine gene fission events, either by break up of an open reading frame (four events identified) or loss of a component domain (five events identified). This indicates that this three gene fusion is highly labile. These data are consistent with a growing body of data indicating gene fission events occur at high relative rates. Accounting for these sources of homoplasy, our data suggest that the folB-folK-folP gene fusion was present in the last common ancestor of Amoebozoa and Opisthokonta but absent in the Metazoa including the human genome. Comparative genomic data of these genes provides an important resource for designing therapeutic strategies targeting the de novo folate biosynthesis pathway of a variety of eukaryotic pathogens such as Acanthamoeba castellanii.
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Affiliation(s)
- Finlay Maguire
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Fiona L Henriquez
- Infection and Microbiology Research Group, Institute of Biomedical and Environmental Health Research, School of Science, University of the West of Scotland, Paisley, Renfrewshire, United Kingdom
| | - Guy Leonard
- Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom
| | - Joel B Dacks
- Department of Life Sciences, Natural History Museum, London, United Kingdom Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew W Brown
- Department of Biological Sciences, Mississippi State University
| | - Thomas A Richards
- Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom Canadian Institute for Advanced Research, CIFAR Program in Integrated Microbial Biodiversity
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PrestoBlue® and AlamarBlue® are equally useful as agents to determine the viability of Acanthamoeba trophozoites. Exp Parasitol 2014; 145 Suppl:S69-72. [PMID: 24703973 DOI: 10.1016/j.exppara.2014.03.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 03/19/2014] [Accepted: 03/23/2014] [Indexed: 11/23/2022]
Abstract
Acanthamoeba is an opportunistic pathogen which is the causal agent of several human infections such as Granulomatous Amoebic Encephalitis, Acanthamoeba keratitis and other disseminated infections. Furthermore, current therapeutic measures against Acanthamoeba infections are arduous, and show limited efficacy against the cyst stage of Acanthamoeba. There is a pressing need to search and evaluate new therapeutic agents against these protozoa. Our approach for evaluating possible new drugs is an initial in vitro screening assay based on general metabolic activity of the cells. In this study we compare two agents, AlamarBlue® and PrestoBlue® for this initial screen. Both reagents can be used to indicate metabolism by changes in their absorbance or fluorescence. The assay is carried out in a 96-well plate format and fluorescence can be measured after an inoculation period of as little as 10 min, but more typically 96 h. This to the best of our knowledge this is the first time that both compounds are directly compared using absorbance and fluorescence measurement. We conclude that for the specific case of Acanthamoeba both agents AlamarBlue® and PrestoBlue® are equally useful to determine cell viability.
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In vitro efficacy of corifungin against Acanthamoeba castellanii trophozoites and cysts. Antimicrob Agents Chemother 2013; 58:1523-8. [PMID: 24366747 DOI: 10.1128/aac.02254-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Painful blinding keratitis and fatal granulomatous amebic encephalitis are caused by the free-living amebae Acanthamoeba spp. Several prescription eye medications are used to treat Acanthamoeba keratitis, but the infection can be difficult to control because of recurrence of infection. For the treatment of encephalitis, no single drug was found useful, and in spite of the use of a combination of multiple drugs, the mortality rate remains high. Therefore, efficient, novel drugs are urgently needed for the treatment of amebic keratitis and granulomatous amebic encephalitis. In this study, we identified corifungin, a water-soluble polyene macrolide, as amebicidal. In vitro, it was effective against both the trophozoites and the cysts. Transmission electron microscopy of Acanthamoeba castellanii incubated with corifungin showed the presence of swollen mitochondria, electron-dense granules, degeneration of cytoplasm architecture, and loss of nuclear chromatin structure. These changes were followed by lysis of amebae. Corifungin also induced the encystment process of A. castellanii. There were alterations in the cyst cell wall followed by lysis of the cysts. Corifungin is a promising therapeutic option for keratitis and granulomatous amebic encephalitis.
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Lorenzo-Morales J, Martín-Navarro CM, López-Arencibia A, Arnalich-Montiel F, Piñero JE, Valladares B. Acanthamoeba keratitis: an emerging disease gathering importance worldwide? Trends Parasitol 2013; 29:181-7. [PMID: 23433689 DOI: 10.1016/j.pt.2013.01.006] [Citation(s) in RCA: 192] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/23/2013] [Accepted: 01/28/2013] [Indexed: 11/15/2022]
Abstract
Acanthamoeba keratitis (AK) is increasingly being recognized as a severe sight-threatening ocular infection worldwide. Although contact lens wear is the leading risk factor for AK, Acanthamoeba parasites are also an important cause of keratitis in non-contact lens wearers. Diagnosis of AK is challenging, and the available treatments are lengthy and not fully effective against all strains. The pathogenesis of Acanthamoeba is still under study, and the identification of the key factors involved in this process should be useful for the development of fully effective therapies. This review focuses on recent developments on AK pathogenesis and diagnosis as well as novel strategies for the evaluation of anti-amoebic agents that could be applied in the near future against these pathogens.
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Affiliation(s)
- Jacob Lorenzo-Morales
- University Institute of Tropical Diseases and Public Health of The Canary Islands, University of La Laguna, Avenida Astrofísico Francisco Sánchez SN, 38203 La Laguna, Tenerife, Canary Islands, Spain.
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Abstract
AIMS The purpose of this study was to estimate the duration of treatment necessary for sequential acanthamoeba laboratory tests from corneal scrapings to become negative, and to assess predictors that affect this duration period. METHODS We included all patients with at least one positive acanthamoeba culture or Giemsa stain at the F.I. Proctor Foundation Microbiology Laboratory from 1996 to 2009. A parametric survival analysis was performed among patients with repeat cultures to assess significant predictors for extended clearance time. Simulations were performed to estimate clearance time in the entire patient population, assuming imperfect sensitivity. RESULTS Thirty-seven patients with laboratory evidence of acanthamoeba had testing at 69 time points. The median clearance time among eyes with repeat cultures was 42.5 days (interquartile range (IQR) 22.0-82.0 days; unadjusted parametric model). Initial visual acuity was the only predictor significantly associated with clearance time in univariate analyses (P<0.0001). Using initial visual acuity as a predictor for clearance time among the entire patient population, the estimated clearance time decreased to 38.7 days (95% confidence interval (CI) 27.9-53.5 days). When the imperfect sensitivity of the culture technique was also taken into account, the estimated clearance time was 44.1 days (95% CI 31.9-61.0 days). CONCLUSION The duration of infection with acanthamoeba keratitis undergoing treatment has not been well characterized. In this report we estimate a median clearance time of approximately 6 weeks, with an IQR of 22-82 days.
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Drug discovery and the use of computational approaches for infectious diseases. Future Med Chem 2011; 3:1011-25. [DOI: 10.4155/fmc.11.60] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
For centuries infectious diseases were the scourge of humanity, overcome only by the discovery of vaccination and penicillin. With an armamentarium of effective antibiotics, vaccines and drugs at hand, infectious diseases for many years were considered to be negligible. With the onset of the AIDS pandemic, the return of tuberculosis and influenza (e.g., swine influenza) this notion has changed in recent years. Drug discovery for infectious diseases, therefore, is again gaining increasing interest. This article discusses the drug-discovery process in this area and introduces major computational approaches used to identify suitable drug targets and to discover and optimize chemical lead compounds towards drug candidates using examples from antiparasitic drug discovery.
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Amebic meningoencephalitides and keratitis: challenges in diagnosis and treatment*. Curr Opin Infect Dis 2010; 23:590-4. [DOI: 10.1097/qco.0b013e32833ed78b] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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