In Vitro Amoebicidal Activity of Titanium Dioxide/UV-A Combination Against<i>Acanthamoeba</i>

Gomart, Gabrielle; Denis, Julie; Bourcier, Tristan; Dory, Anne; Abou-Bacar, Ahmed; Candolfi, Ermanno; Sauer, Arnaud

doi:10.1167/iovs.18-25003

Cited by 13 publications

(5 citation statements)

References 36 publications

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“…However, the effects of unconjugated metal nanoparticles against A. castellanii have not been studied extensively. In recent reports, titanium oxide nanoparticles have shown in vitro antiacanthamoebic potential triggered by ultraviolet radiation [17], while doping with zinc oxide nanoparticles has shown improved photochemotherapy [18]. In another report, gold and silver nanoparticles have been shown to improve the antiacanthamoebic effects of commercially available contact lens disinfection solutions [19].…”

Section: Introductionmentioning

confidence: 99%

Cobalt nanoparticles as novel nanotherapeutics against Acanthamoeba castellanii

et al. 2019

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Background Species of Acanthamoeba are facultative pathogens which can cause sight threatening Acanthamoeba keratitis and a rare but deadly brain infection, granulomatous amoebic encephalitis. Due to conversion of Acanthamoeba trophozoites to resistant cyst stage, most drugs are found to be ineffective at preventing recurrence of infection. This study was designed to test the antiacanthamoebic effects of different cobalt nanoparticles (CoNPs) against trophozoites and cysts, as well as parasite-mediated host cell cytotoxicity. Methods Three different varieties of CoNPs were synthesized by utilizing hydrothermal and ultrasonication methods and were thoroughly characterized by X-ray diffraction and field emission scanning electron microscopy. Amoebicidal, encystation, excystation, and host cell cytopathogenicity assays were conducted to study the antiacanthamoebic effects of CoNPs. Results The results of the antimicrobial evaluation revealed that cobalt phosphate Co 3 (PO 4 ) 2 hexagonal microflakes, and 100 nm large cobalt hydroxide (Co(OH) 2 ) nanoflakes showed potent amoebicidal activity at 100 and 10 µg/ml against Acanthamoeba castellanii as compared to granular cobalt oxide (Co 3 O 4 ) of size 35–40 nm. Furthermore, encystation and excystation assays also showed consistent inhibition at 100 µg/ml. CoNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release without causing significant damage to human cells when treated alone. Conclusions To our knowledge, these findings determined, for the first time, the effects of composition, size and morphology of CoNPs against A. castellanii . Co 3 (PO 4 ) 2 hexagonal microflakes showed the most promising antiamoebic effects as compared to Co(OH) 2 nanoflakes and granular Co 3 O 4 . The results reported in the present study hold potential for the development of antiamoebic nanomedicine.

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Section: Introductionmentioning

confidence: 99%

Cobalt nanoparticles as novel nanotherapeutics against Acanthamoeba castellanii

et al. 2019

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“…The trophozoites were incubated at 30 °C for 24 h. The number of viable trophozoites was determined by adding 0.1% trypan blue to each well. Dead trophozoites that stained blue and live trophozoites that remained unstained were counted using a Neubauer haemocytometer (Hirschmann, Germany) [ 36 ].…”

Section: Methodsmentioning

confidence: 99%

The Activity of Polyhomoarginine against Acanthamoeba castellanii

Peguda

Lakshminarayanan

Carnt

et al. 2022

Biology

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Arginine-rich peptides can have broad-spectrum anti-bacterial and anti-fungal activities. Polyhomoarginine consists of highly cationic residues which can act on the negatively charged microbial cell membranes. Acanthamoeba is a free-living protozoan known to cause a rare corneal infection which is difficult to diagnose and treat. This study evaluated the activity of the polyhomoarginines against Acanthamoeba castellanii. Acanthamoeba amoebicidal, amoebistatic, encystation and excystment assays were performed using protocols described in the literature. The activity of polyhomoarginines (PHAs) of different lengths (10 to 400 residues) was measured against the trophozoites and cysts of Acanthamoeba castellanii ATCC30868 in concentrations ranging from 0.93 µM to 15 µM. Data were represented as mean ± SE and analysed using one-way ANOVA. Overall, PHAs demonstrated good anti-acanthamoeba activity against both trophozoites and cysts. PHA 30 reduced the number of viable trophozoites by 99%, inhibited the formation of cysts by 96% and the emergence of trophozoites from cysts by 67% at 3.75 μM. PHA 10 was similarly active, but at a slightly higher concentration of 15 µM, reducing the numbers of viable trophozoites by 98%, inhibiting cyst formation by 84% and preventing the emergence of trophozoites from cysts by 99%. At their greatest anti-amoeba concentrations, PHA 10 gave only 8% haemolysis at 15 μM while PHA 30 gave <40 % haemolysis at 3.75 μM. Polyhomoarginine 10 showed excellent anti-amoebic activity against both forms of Acanthamoeba castellanii and was non-toxic at its most active concentrations. This implies that polyhomoarginines can be developed into a potential therapeutic agent for Acanthamoeba keratitis. However, there is a need to carry out further pre-clinical and then in vivo experiments in the AK animal model.

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“…Hence AgTANPs were more significant than pure AgNPs and AuNPs (Padzik et al, 2018). In recent reports, titanium oxide nanoparticles have shown in vitro antiacanthamoebic effects triggered by ultraviolet radiations (Gomart et al, 2018), while doping with zinc oxide nanoparticles have shown improved photochemotherapy (Imran et al, 2016).…”

Section: A Castellaniimentioning

confidence: 99%

Anti-amoebic potential of azole scaffolds and nanoparticles against pathogenic Acanthamoeba

et al. 2020

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Acanthamoeba spp. are free living amoeba (FLA) which are widely distributed in nature. They are opportunistic parasites and can cause severe infections to the eye, skin and central nervous system. The advances in drug discovery and modifications in the chemotherapeutic agents have shown little improvement in morbidity and mortality rates associated with Acanthamoeba infections. The mechanism-based process of drug discovery depends on the molecular drug targets present in the signaling pathways in the genome. Synthetic libraries provide a platform for broad spectrum of activities due to their desired structural modifications. Azoles, originally a class of synthetic anti-fungal drugs, disrupt the fungal cell membrane by inhibiting the biosynthesis of ergosterol through the inhibition of cytochrome P450 dependent 14α-lanosterol, a key step of the sterol pathway. Acanthamoeba and fungi share the presence of similar sterol intermediate, as ergosterol is also the major endproduct in the sterol biosynthesis in Acanthamoeba. Sterols present in the eukaryotic cell membrane are one of the most essential lipids and exhibit important structural and signaling functions. Therefore, in this review we highlight the importance of specific targeting of ergosterol present in Acanthamoebic membrane by azole compounds for amoebicidal activity. Previously, azoles have also been repurposed to report antimicrobial, antiparasitic and antibacterial properties. Moreover, by loading the azoles into nanoparticles through advanced techniques in nanotechnology, such as physical encapsulation, adsorption, or chemical conjugation, the pharmacokinetics and therapeutic index of the drugs can be significantly improved. The current review proposes an important strategy to target Acanthamoeba using synthetic libraries of azoles and their conjugated nanoparticles for the first time.

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In Vitro Amoebicidal Activity of Titanium Dioxide/UV-A Combination AgainstAcanthamoeba

Abstract: Given the in vitro synergistic effectiveness of the association of chlorhexidine with TiO2 and UV-A against cysts, the treatment of Acanthamoeba keratitis could be improved by this new therapeutic approach.

Cited by 13 publications

References 36 publications

Cobalt nanoparticles as novel nanotherapeutics against Acanthamoeba castellanii

Cobalt nanoparticles as novel nanotherapeutics against Acanthamoeba castellanii

The Activity of Polyhomoarginine against Acanthamoeba castellanii

Anti-amoebic potential of azole scaffolds and nanoparticles against pathogenic Acanthamoeba

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