RESUMO
Representatives of the genus Acanthamoeba are among the most widespread protists in the environment. They have a ubiquitous distribution and can sometimes cause quite serious pathologies in humans. The treatment ofp rotozoal infections caused by free-living amoebae is currently limited and often unsuccessful. In the presented investigation, amebicidal activity was determined against both the trophozoites and cysts of Acanthamoeba spp., which were isolated during the microbiological examination of environmental objects. The inhibitory activity of drugs in vitro was determined using the authors' proposed method, which is based on the plaque formation phenomenon: this is initiated by free-living amoebae when cultured in agar containing the bacteria Cellulosimicrobium sp. strain bent-1. Based on a series of experimental studies, the paper proposes a reliable and inexpensive method for determining the anti-protozoal activity of medicinal agents, which will significantly complement the current screening method system when studying existing drugs, or new drugs during their development stage.
Assuntos
Acanthamoeba , Acanthamoeba/efeitos dos fármacos , Antiprotozoários/farmacologia , Trofozoítos/efeitos dos fármacos , Amebicidas/farmacologiaRESUMO
Introduction: Acanthamoeba infection is a serious public health concern, necessitating the development of effective and safe anti-Acanthamoeba chemotherapies. Poly (ADP-ribose) polymerases (PARPs) govern a colossal amount of biological processes, such as DNA damage repair, protein degradation and apoptosis. Multiple PARP-targeted compounds have been approved for cancer treatment. However, repurposing of PARP inhibitors to treat Acanthamoeba is poorly understood. Methods: In the present study, we attempted to fill these knowledge gaps by performing anti-Acanthamoeba efficacy assays, cell biology experiments, bioinformatics, and transcriptomic analyses. Results: Using a homology model of Acanthamoeba poly (ADP-ribose) polymerases (PARPs), molecular docking of approved drugs revealed three potential inhibitory compounds: olaparib, venadaparib and AZ9482. In particular, venadaparib exhibited superior docking scores (-13.71) and favorable predicted binding free energy (-89.28 kcal/mol), followed by AZ9482, which showed a docking score of -13.20 and a binding free energy of -92.13 kcal/mol. Notably, the positively charged cyclopropylamine in venadaparib established a salt bridge (through E535) and a hydrogen bond (via N531) within the binding pocket. For comparison, AZ9482 was well stacked by the surrounding aromatic residues including H625, Y652, Y659 and Y670. In an assessment of trophozoites viability, AZ9482 exhibited a dose-and time-dependent anti-trophozoite effect by suppressing Acanthamoeba PARP activity, unlike olaparib and venadaparib. An Annexin V-fluorescein isothiocyanate/propidium iodide apoptosis assay revealed AZ9482 induced trophozoite necrotic cell death rather than apoptosis. Transcriptomics analyses conducted on Acanthamoeba trophozoites treated with AZ9482 demonstrated an atlas of differentially regulated proteins and genes, and found that AZ9482 rapidly upregulates a multitude of DNA damage repair pathways in trophozoites, and intriguingly downregulates several virulent genes. Analyzing gene expression related to DNA damage repair pathway and the rate of apurinic/apyrimidinic (AP) sites indicated DNA damage efficacy and repair modulation in Acanthamoeba trophozoites following AZ9482 treatment. Discussion: Collectively, these findings highlight AZ9482, as a structurally unique PARP inhibitor, provides a promising prototype for advancing anti-Acanthamoeba drug research.
Assuntos
Simulação de Acoplamento Molecular , Inibidores de Poli(ADP-Ribose) Polimerases , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Humanos , Piperazinas/farmacologia , Ftalazinas/farmacologia , Ftalazinas/química , Reposicionamento de Medicamentos , Poli(ADP-Ribose) Polimerases/metabolismo , Acanthamoeba/efeitos dos fármacos , Biologia Computacional , Apoptose/efeitos dos fármacos , Perfilação da Expressão Gênica , Antiprotozoários/farmacologia , Trofozoítos/efeitos dos fármacosRESUMO
Although rare, amoebic keratitis (AK) is a disease caused by Acanthamoeba spp. that can lead to blindness. The drugs currently available for its treatment are very toxic, which has motivated the investigation for more effective and safe therapeutic options. In this study, the in vitro activity of ß-caryophyllene (BCP) was exploited taking into account its action against other protozoans as well as its well-known healing and anti-inflammatory properties (aspects relevant for the AK pathogenesis). On the other hand, high volatilization and oxidation phenomena are found for this compound, which led to its incorporation into nanoemulsions (NEs). Two emulsifying agents were tested, resulting in monodisperse systems with reduced droplet size (<265 nm) and high surface charge (positive and negative for NEs prepared with cetrimonium bromide -CTAB and Phosal® 50+, respectively). NEs prepared with CTAB were shown to be more stable after long-term storage at 4 and 25 °C than those prepared with Phosal®. Pure BCP, at the highest concentration (500 µM), resulted in a level of inhibition of Acanthamoeba trophozoites equivalent to that of reference drug (chlorhexidine). This activity was even greater after oil nanoencapsulation. The reduced droplet size could improve the interaction of the oil with the microorganism, justifying this finding. Changes in surface charge did not impact the activity. Positively charged NEs improved the interaction and retention of BCP in the cornea and thus should be prioritized for further studies.
Assuntos
Ceratite por Acanthamoeba , Emulsões , Sesquiterpenos Policíclicos , Ceratite por Acanthamoeba/tratamento farmacológico , Ceratite por Acanthamoeba/parasitologia , Sesquiterpenos Policíclicos/química , Nanopartículas , Administração Oftálmica , Cetrimônio/química , Animais , Acanthamoeba/efeitos dos fármacos , Estabilidade de Medicamentos , Tamanho da Partícula , Soluções Oftálmicas , HumanosRESUMO
The pathogenic free-living amoebae, Naegleria fowleri and Acanthamoeba polyphaga, are found in freshwater, soil, and unchlorinated or minimally chlorinated swimming pools. N. fowleri and A. polyphaga are becoming problematic as water leisure activities and drinking water are sources of infection. Chlorine dioxide (ClO2) gas is a potent disinfectant that is relatively harmless to humans at the concentration used for disinfection. In this study, we examined the amoebicidal effects of ClO2 gas on N. fowleri and A. polyphaga. These amoebae were exposed to ClO2 gas from a ready-to-use product (0.36 ppmv/h) for 12, 24, 36, and 48 h. Microscopic examination showed that the viability of N. fowleri and A. polyphaga was effectively inhibited by treatment with ClO2 gas in a time-dependent manner. The growth of N. fowleri and A. polyphaga exposed to ClO2 gas for 36 h was completely inhibited. In both cases, the mRNA levels of their respective actin genes were significantly reduced following treatment with ClO2 gas. ClO2 gas has an amoebicidal effect on N. fowleri and A. polyphaga. Therefore, ClO2 gas has been proposed as an effective agent for the prevention and control of pathogenic free-living amoeba contamination.
Assuntos
Acanthamoeba , Compostos Clorados , Desinfetantes , Naegleria fowleri , Óxidos , Compostos Clorados/farmacologia , Naegleria fowleri/efeitos dos fármacos , Acanthamoeba/efeitos dos fármacos , Óxidos/farmacologia , Desinfetantes/farmacologia , Fatores de Tempo , Análise de Sobrevida , Amebicidas/farmacologiaRESUMO
Acanthamoeba are free-living pathogenic protozoa that cause blinding keratitis, disseminated infection, and granulomatous amebic encephalitis, which is generally fatal. The development of efficient and safe drugs is a critical unmet need. Acanthamoeba sterol 14α-demethylase (CYP51) is an essential enzyme of the sterol biosynthetic pathway. Repurposing antifungal azoles for amoebic infections has been reported, but their inhibitory effects on Acanthamoeba CYP51 enzymatic activity have not been studied. Here, we report catalytic properties, inhibition, and structural characterization of CYP51 from Acanthamoeba castellanii. The enzyme displays a 100-fold substrate preference for obtusifoliol over lanosterol, supporting the plant-like cycloartenol-based pathway in the pathogen. The strongest inhibition was observed with voriconazole (1 h IC50 0.45 µM), VT1598 (0.25 µM), and VT1161 (0.20 µM). The crystal structures of A. castellanii CYP51 with bound VT1161 (2.24 Å) and without an inhibitor (1.95 Å), presented here, can be used in the development of azole-based scaffolds to achieve optimal amoebicidal effectiveness.
Assuntos
Inibidores de 14-alfa Desmetilase , Esterol 14-Desmetilase , Esterol 14-Desmetilase/metabolismo , Esterol 14-Desmetilase/química , Inibidores de 14-alfa Desmetilase/farmacologia , Inibidores de 14-alfa Desmetilase/química , Inibidores de 14-alfa Desmetilase/síntese química , Relação Estrutura-Atividade , Acanthamoeba/enzimologia , Acanthamoeba/efeitos dos fármacos , Acanthamoeba castellanii/enzimologia , Acanthamoeba castellanii/efeitos dos fármacos , Cristalografia por Raios X , Antiprotozoários/farmacologia , Antiprotozoários/química , Antiprotozoários/síntese química , Modelos Moleculares , Estrutura MolecularRESUMO
OBJECTIVE: Microbial keratitis (MK) is a significant cause of blindness in sub-Saharan Africa. We investigated the feasibility of using a novel corneal impression membrane (CIM) for obtaining and processing samples by culture, PCR and whole-genome sequencing (WGS) in patients presenting with suspected MK in Malawi. METHODS AND ANALYSIS: Samples were collected from patients presenting with suspected MK using a 12 mm diameter polytetrafluoroethylene CIM disc. Samples were processed using culture and PCR for Acanthamoeba, herpes simplex virus type 1 (HSV-1) and the bacterial 16S rRNA gene. Minimum inhibitory concentrations of isolates to eight antimicrobials were measured using susceptibility strips. WGS was used to characterise Staphylococcus aureus isolates. RESULTS: 71 eyes of 71 patients were included. The overall CIM isolation rate was 81.7% (58 positive samples from 71 participants). 69 (81.2%) of isolates were Gram-positive cocci. Coagulase-negative Staphylococcus 31.8% and Streptococcus species 14.1% were the most isolated bacteria. Seven (9.9%) participants were positive for HSV-1. Fungi and Acanthamoeba were not detected. Moxifloxacin and chloramphenicol offered the best coverage for both Gram-positive and Gram-negative isolates when susceptibility was determined using known antimicrobial first quartile concentrations and European Committee on Antimicrobial Susceptibility Testing breakpoints, respectively. WGS identified known virulence genes associated with S. aureus keratitis. CONCLUSIONS: In a resource-poor setting, a CIM can be used to safely sample the cornea in patients presenting with suspected MK, enabling identification of causative microorganisms by culture and PCR. Although the microbiological spectrum found was limited to the dry season, these preliminary results could be used to guide empirical treatment.
Assuntos
Infecções Oculares Bacterianas , Humanos , Projetos Piloto , Malaui/epidemiologia , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Infecções Oculares Bacterianas/microbiologia , Infecções Oculares Bacterianas/epidemiologia , Infecções Oculares Bacterianas/tratamento farmacológico , Adulto Jovem , Bactérias/isolamento & purificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Testes de Sensibilidade Microbiana , Córnea/microbiologia , Ceratite/microbiologia , Ceratite/tratamento farmacológico , Ceratite/epidemiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Idoso , Reação em Cadeia da Polimerase , Adolescente , Acanthamoeba/isolamento & purificação , Acanthamoeba/genética , Acanthamoeba/efeitos dos fármacos , RNA Ribossômico 16S/genéticaRESUMO
To date, no studies have addressed the role of neurotrophins (NTs) in Acanthamoeba spp. infections in the brain. Thus, to clarify the role of NTs in the cerebral cortex and hippocampus during experimental acanthamoebiasis in relation to the host immune status, the purpose of this study was to determine whether Acanthamoeba spp. may affect the concentration of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4) in brain structures. Our results suggest that at the beginning of infection in immunocompetent hosts, BDNF and NT-3 may reflect an endogenous attempt at neuroprotection against Acanthamoeba spp. infection. We also observed a pro-inflammatory effect of NGF during acanthamoebiasis in immunosuppressed hosts. This may provide important information for understanding the development of cerebral acanthamoebiasis related to the immunological status of the host. However, the pathogenesis of brain acanthamoebiasis is still poorly understood and documented and, therefore, requires further research.
Assuntos
Acanthamoeba , Amebíase , Fatores de Crescimento Neural , Acanthamoeba/efeitos dos fármacos , Amebíase/tratamento farmacológico , Encéfalo/metabolismo , Encéfalo/microbiologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Humanos , Fator de Crescimento Neural/metabolismo , Fatores de Crescimento Neural/metabolismo , Neurotrofina 3/metabolismoRESUMO
Microbial keratitis is a devastating disease that can cause eye damage and blindness and can be the result of infections by several common ocular pathogens. Importantly, some of these pathogens, such as Acanthamoeba, are particularly unsusceptible to biocides in common contact lens care solutions. Therefore, the disinfection efficacy of preservative-free (PF) disinfection systems against bacteria, fungi, and Acanthamoeba trophozoites and cysts should be assessed as products with the most potential to be efficacious against resistant organisms. PF disinfection systems were analyzed for antimicrobial efficacy. These were the one-step (hydrogen peroxide-based) Clear Care and Clear Care Plus systems and the two-step (povidone-iodine-based) Cleadew system. Stand-alone challenges using bacteria, fungi, and Acanthamoeba were prepared according to the International Standards Organization method 14729. These same challenges were also conducted in the presence of the following contact lenses: Boston RGP, Acuvue Oasys, Biofinity, Ultra, and 2-week PremiO. All challenges were performed at the manufacturer's recommended disinfection time. All preservative-free disinfection systems demonstrated similarly high rates of antimicrobial efficacy when challenged with bacteria or fungi, with or without lenses. However, both Clear Care and Clear Care Plus demonstrated significantly greater disinfection efficacy against Acanthamoeba trophozoites and cysts, with and without lenses (P < 0.05). Cleadew efficacy was impacted by the addition of contact lenses, whereas Clear Care/Clear Care Plus maintained similar efficacies in the absence or presence of lenses. While both hydrogen peroxide and povidone-iodine are highly effective against bacteria and fungi, hydrogen peroxide maintains significantly greater disinfection capabilities than povidone-iodine against all forms of Acanthamoeba. IMPORTANCE Understanding the most efficacious products will allow clinicians to best communicate to patients and consumers the safest products on the market to reduce adverse events, including microbial keratitis, during contact lens use.
Assuntos
Anti-Infecciosos/farmacologia , Soluções para Lentes de Contato/farmacologia , Desinfecção/métodos , Oftalmopatias/prevenção & controle , Acanthamoeba/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Lentes de Contato/microbiologia , Lentes de Contato/parasitologia , Desinfecção/instrumentação , Oftalmopatias/microbiologia , Oftalmopatias/parasitologia , Fungos/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/farmacologia , Povidona-Iodo/farmacologiaRESUMO
Acanthamoeba keratitis infection extends due to the growing number of contact lens users. Indigenous plants including Garcinia mangostana play a vital role in human health and well being. Many species of this plant have been reported with myriads of potent medicinal properties. However, the aims of this study were, for the first time, to isolate compounds from the flower of G. mangostana and to test their anti-Acanthamoeba and anti-adhesion activity against Acanthamoeba triangularis. Powdered flowers of G. mangostana were extracted and chromatographed on a silica gel column. The structures of the compounds were established with the aid of 1H NMR. More so, the anti-Acanthamoeba and anti-adhesion properties were tested on a 96-well polystyrene microtiter plate and soft contact lenses. Scanning electron microscope (SEM) was used to determine the features of A. triangularis on contact lenses. Eight pure compounds were obtained, namely 9-hydroxycalabaxanthone, tovophillin A, garcinone E, garcinone B, α-mangostin, gartinin, 8-deoxygartinin and γ-mangostin. The extract and pure compounds exhibited anti-Acanthamoeba activity with MIC values in the range of 0.25-1 mg/mL. In addition, the extract and α-mangostin displayed significant activity against the adhesion of A. triangularis trophozoites both in polystyrene plate and in contact lenses at 0.5 × MIC (0.25 mg/mL). Furthermore, α-mangostin has the potential to remove A. triangularis adhesion in contact lenses similar to a commercial multipurpose solution (MPS). SEM study confirmed that crude extract and α-mangostin are effective as solutions for contact lenses, which removed A. triangularis trophozoites within 24 h. Alpha-mangostin was non-toxic to Vero cells at a concentration below 39 µM in 24 h. Crude extract of G. mangostana flower and its α-mangostin serve as candidate compounds in the treatment of Acanthamoeba infection or as lens care solution, since they can be used as a source of natural products against Acanthamoeba and virulence factor associated with the adhesion of A. triangularis.
Assuntos
Acanthamoeba , Soluções para Lentes de Contato , Garcinia mangostana , Extratos Vegetais/farmacologia , Acanthamoeba/efeitos dos fármacos , Animais , Chlorocebus aethiops , Flores/química , Garcinia mangostana/química , Humanos , Compostos Fitoquímicos/farmacologia , Células VeroRESUMO
Acanthamoeba keratitis is predominantly caused by genotype T4. We report a case of severe keratitis caused by Acanthamoeba in a 39-year-old man who had prior accidental exposure to a corrosive chemical. The patient developed central full thickness ring infiltration and epithelial defect with hypopyon that required keratoplasty. The acanthamoebae isolated from the patient exhibited thermotolerance phenotype with the capability to grow well at ambient temperature and at 42°C. Analysis of a near complete 18S rRNA gene of this isolate revealed a distinct sequence that can be unequivocally assigned to genotype T12, a rare genotype incriminated in corneal infections.
Assuntos
Ceratite por Acanthamoeba/diagnóstico , Acanthamoeba/genética , Genótipo , Acanthamoeba/classificação , Acanthamoeba/efeitos dos fármacos , Acanthamoeba/patogenicidade , Ceratite por Acanthamoeba/tratamento farmacológico , Adulto , Antiprotozoários/uso terapêutico , Infecções Oculares Parasitárias/diagnóstico , Infecções Oculares Parasitárias/tratamento farmacológico , Humanos , Masculino , Filogenia , RNA Ribossômico 18S/genética , Análise de Sequência de DNA , Índice de Gravidade de Doença , TailândiaRESUMO
Acanthamoebae are opportunistic pathogens that cause serious infections, including Acanthamoeba keratitis, a sight-threatening disease affecting mainly contact lens wearers, and granulomatous amoebic encephalitis, an infection of the central nervous system that occurs mostly in immunocompromised individuals. Although these infections are rare, they are a challenge for healthcare providers. In the last decade, the search for and implementation of novel treatment approaches against these parasites and the infections they cause have intensified, but current options are still unsatisfactory. The aim of this study was to investigate the in vitro activity of the gold-based compound auranofin against Acanthamoeba spp. The study showed that auranofin has potent antimicrobial activity against Acanthamoeba spp., with an IC50 ranging from 2.9 to 3.48 µM, and thus may be useful in the prevention and control of Acanthamoeba infections.
Assuntos
Acanthamoeba/efeitos dos fármacos , Amebíase/tratamento farmacológico , Antiparasitários/farmacologia , Auranofina/farmacologia , Acanthamoeba/crescimento & desenvolvimento , Ceratite por Acanthamoeba/tratamento farmacológico , Ceratite por Acanthamoeba/parasitologia , Amebíase/parasitologia , Encefalite/tratamento farmacológico , Encefalite/parasitologia , Humanos , Testes de Sensibilidade ParasitáriaRESUMO
Nanomedicine has the potential in enhancing the efficacy and bioavailability of anti-infective agents. Here we determined whether conjugation of the Malaysian cultivated seaweed Kappaphycus alvarezii with silver-conjugated nanoparticles enhanced anti-acanthamoebic properties. Silver-conjugated K. alvarezii were successfully synthesized, followed by characterization with Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, and transmission electron microscopy. Amoebicidal effects were evaluated against Acanthamoeba castellanii, and cytotoxicity assays were performed using HaCaT cells. Viability assays revealed that silver nanoparticles conjugated with K. alvarezii extract exhibited significant antiamoebic properties (P < 0.05). Nano-conjugates induced the production of reactive oxygen species. Importantly, silver-conjugated extract inhibited amoeba-mediated host cell damage as established by lactate dehydrogenase release. Neither the nano-conjugates nor the extract showed cytotoxicity against human cells in vitro. Liquid chromatography and mass spectroscopy revealed several molecules, including 2,6-nonadien-1-ol, N-desmethyl trifluoperazine, dulciol B, lucidumol A, acetoxolone, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, C16 sphinganine, 22-tricosenoic acid, and ß-dihydrorotenone, of which dulciol B and C16 sphinganine are known to possess antimicrobial activities. In summary, marine organisms are an important source of bioactive molecules with anti-acanthamoebic properties that can be enhanced by conjugating with silver nanoparticles. Natural products combined with nanotechnology using multifunctional nanoparticle complexes can deliver therapeutic agents effectively and hold promise in the development of new formulations of anti-acanthamoebic agents.
Assuntos
Acanthamoeba/efeitos dos fármacos , Nanopartículas Metálicas/uso terapêutico , Rodófitas/química , Prata/metabolismo , Humanos , Malásia , Espécies Reativas de Oxigênio/metabolismo , Prata/uso terapêuticoRESUMO
Acanthamoeba spp. are widely distributed in the environment and cause serious infections in humans. Treatment of Acanthamoeba infections is very challenging and not always effective which requires the development of more efficient drugs against Acanthamoeba spp. The purpose of the present study was to test medicinal plants that may be useful in the treatment of Acanthamoeba spp. Here we evaluated the trophozoital and cysticidal activity of 13 flavonoid glycosides isolated from Delphinium gracile, D. staphisagria, Consolida oliveriana and from Aconitum napellus subsp. Lusitanicum against the amoeba Acanthamoeba castellanii. AlamarBlue Assay Reagent® was used to determine the activity against trophozoites of A. castellanii, and cytotoxic using Vero cells. Cysticidal activity was assessed on treated cysts by light microscopy using a Neubauer chamber to quantify cysts and trophozoites. Flavonoids 1, 2, 3 and 4 showed higher trophozoital activity and selectivity indexes than the reference drug chlorhexidine digluconate. In addition, flavonoid 2 showed 100% cysticidal activity at a concentration of 50 µm, lower than those of the reference drug and flavonoid 3 (100 µm). These results suggest that flavonoids 2 and 3 might be used for the development of novel therapeutic approaches against Acanthamoeba infections after satisfactory in vivo evaluations.
Assuntos
Acanthamoeba/efeitos dos fármacos , Aconitum/química , Delphinium/química , Glicosídeos/farmacologia , Extratos Vegetais/farmacologia , Ranunculaceae/química , Acanthamoeba/crescimento & desenvolvimento , Animais , Chlorocebus aethiops , Flavonoides/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Flavonoides/toxicidade , Glicosídeos/química , Glicosídeos/isolamento & purificação , Glicosídeos/toxicidade , Concentração Inibidora 50 , Estrutura Molecular , Extratos Vegetais/isolamento & purificação , Trofozoítos/efeitos dos fármacos , Trofozoítos/crescimento & desenvolvimento , Células Vero/efeitos dos fármacosRESUMO
The validation of anti-Acanthamoeba activity of commercial eye drops has gained a great interest recently and a growing number of commercials eye drop were evaluated for their aptitude to inhibit Acanthamoeba as a second pharmacological effect. In the present study, three different eye drops, commercializing in Spain, including TobraDex, Cusimolol and Colircusi antiedema have been tested in vitro against trophozoites and cysts stage of the facultative pathogen Acanthamoeba. The alamarBlue™ method was used to evaluate both trophocidal and cysticidal properties. The most active eye drops were tested for their impact on some programmed cell death features. We found out that the cells inhibition was strain and eye drop dependent, and 5% eye drop was able to eliminate both trophozoite and cyst stage of Acanthamoeba spp. A treatment of 24 h with 5% of TobraDex or Cusimolol was able to show DNA condensation, collapse in the mitochondrial membrane potential and reduction of the ATP level production in Acanthamoeba. We could assume that the present eye drops could induce programed cell death like process in Acanthamoeba via mitochondrial pathway.
Assuntos
Acanthamoeba , Amebicidas , Soluções Oftálmicas , Acanthamoeba/efeitos dos fármacos , Amebicidas/farmacologia , Amebicidas/uso terapêutico , Soluções Oftálmicas/farmacologia , Soluções Oftálmicas/uso terapêutico , TrofozoítosRESUMO
Opportunistic parasitic protozoa of genus Acanthamoeba are responsible to cause severe infections in humans such as Acanthamoeba Keratitis or Amoebic Granulomatous Encephalitis. Current treatments are usually toxic and inefficient and there is a need to access new therapeutic agents. The antiamoebic effects of nephthediol (1) and fourteen germacranolide and eudesmanolide sesquiterpene lactones (2-5, 7-12) isolated from the indigenous zoanthid Palythoa aff. clavata collected at the coast of Lanzarote, Canary Islands were studied against Acanthamoeba castellanii Neff, and the clinical strains A. polyphaga and A. griffini. 4-epi-arbusculin A (11) presented the lowest IC50 value (26,47 ± 1,69 µM) against A. castellanii Neff and low cytotoxicity against murine macrophages, followed by isobadgerin (2), which also showed to be active against A. castellanii Neff cysts. The studies on the mode of action of compounds 2 and 11 revealed these sesquiterpene lactones induce mechanisms of PDC on A. castellanii Neff.
Assuntos
Acanthamoeba/efeitos dos fármacos , Antozoários/química , Antiprotozoários/farmacologia , Lactonas/farmacologia , Sesquiterpenos/farmacologia , Animais , Antiprotozoários/química , Antiprotozoários/isolamento & purificação , Relação Dose-Resposta a Droga , Lactonas/química , Lactonas/isolamento & purificação , Estrutura Molecular , Testes de Sensibilidade Parasitária , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Relação Estrutura-AtividadeRESUMO
To report on Acanthamoeba keratitis cases in a tertiary university eye-hospital in Graz, Austria, over a 21-year period. Retrospective study. Parameters included demographics, diagnostics, clinical courses, medical therapies, surgical interventions, secondary complications, and best spectacle-corrected visual acuity (BSCVA). Patient records for 44 eyes of 42 patients were analysed; 2 bilateral infections. Mean age at presentation was 31 ± 13 (16-65) years; contact lenses were used in 41 of 44 eyes (93.2%). Symptoms at initial presentation were mainly pain (41/43, 95.3%) and photophobia (16/43, 37.2%). Most frequent morphological findings were stromal infiltrates (30/44, 68.2%). Diagnosis was mainly confirmed by smears (40/42, 95.2%) and polymerase chain reaction (8/42, 19%). Antiamoebic treatment comprised biguanides and diamidines. Penetrating keratoplasty was performed in 10/44 (22.7%) eyes. Median time from symptom onset to initial visit was 2 (0-26) weeks; median follow-up was 30 (2-1008) weeks. BSCVA improved in 23/36 (63.9%) eyes, remained unchanged in 6/36 (16.7%) eyes and deteriorated in 7/36 (19.4%) eyes. Acanthamoeba keratitis predominantly occurs in young contact lens wearers. Diagnosis should be considered in patients with pain and stromal infiltrates. In the majority of cases, BSCVA can be improved. Early diagnosis and adequate treatment should be implemented to prevent complications.
Assuntos
Ceratite por Acanthamoeba/epidemiologia , Centros de Atenção Terciária/estatística & dados numéricos , Acanthamoeba/efeitos dos fármacos , Ceratite por Acanthamoeba/diagnóstico , Ceratite por Acanthamoeba/tratamento farmacológico , Ceratite por Acanthamoeba/patologia , Adolescente , Adulto , Idoso , Antiprotozoários/uso terapêutico , Áustria/epidemiologia , Feminino , Humanos , Pressão Intraocular , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Acuidade Visual , Adulto JovemRESUMO
Amoebae of the genus Acanthamoeba are worldwide distributed causative agents of serious human infections such as granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). To date, treatment of these infections is non-uniform and frequently unsuccessful. Recently, the phosphonium salts were studied for their high levels of antimicrobial activity. This work was aimed to investigate the cytotoxic effect of metronidazole and two phosphonium salts (PS1, PS2) on two clinical Acanthamoeba isolates. The isolates showed distinctly higher susceptibility to both phosphonium salts than to metronidazole. The highest susceptibility was noted to PS1 after 48 h of incubation. Metronidazole derivate PS2 showed higher susceptibility than metronidazole. The values of EC50 of PS2 were approximately twenty times lower than EC50 of metronidazole for Acanthamoeba lugdunensis strain and sixteen times lower for Acanthamoeba quina strain after 48 h. Although the therapeutic effect of metronidazole in Acanthamoeba infections is usually insufficient, its derivatisation can result in a significantly higher amoebicidal effect. Cytomorphological changes of trophozoites after exposure to tested compounds included rounding up of the cells, damage of membrane integrity, presence of pathological protrusions, elongation of the cells or pseudocyst-like stages. Obtained results indicate possible therapeutic potential of studied phosphonium salts.
Assuntos
Acanthamoeba/efeitos dos fármacos , Amebicidas/farmacologia , Metronidazol/análogos & derivados , Metronidazol/farmacologia , Trofozoítos/efeitos dos fármacos , Acanthamoeba/genética , Animais , Genótipo , HumanosRESUMO
Curcuma longa and Curcumin have been documented to have a wide spectrum of pharmacological effects, including anti-Acanthamoeba activity. Hence, this study sought to explore the anti-adhesion activity of C. longa extract and Curcumin against Acanthamoeba triangularis trophozoites and cysts in plastic and contact lenses. Our results showed that C. longa extract and Curcumin significantly inhibited the adhesion of A. triangularis trophozoites and cysts to the plastic surface, as investigated by the crystal violet assay (P < 0.05). Also, an 80-90% decrease in adhesion of trophozoites and cysts to the plastic surface was detected following the treatment with C. longa extract and Curcumin at 1/2 × MIC, compared to the control. In the contact lens model, approximately 1 log cells/mL of the trophozoites and cysts was reduced when the cells were treated with Curcumin, when compared to the control. Pre-treatment of the plastic surface with Curcumin at 1/2-MIC reduced 60% and 90% of the adhesion of trophozoites and cysts, respectively. The reduction in 1 Log cells/mL of the adhesion of A. triangularis trophozoites was observed when lenses were pre-treated with both the extract and Curcumin. Base on the results obtained from this study, A. triangularis trophozoites treated with C. longa extract and Curcumin have lost strong acanthopodia, thorn-like projection pseudopodia observed by scanning electron microscope. This study also revealed the therapeutic potentials of C. longa extract and Curcumin, as such, have promising anti-adhesive potential that can be used in the management/prevention of A. triangularis adhesion to contact lenses.
Assuntos
Acanthamoeba , Lentes de Contato , Curcumina , Extratos Vegetais , Acanthamoeba/efeitos dos fármacos , Animais , Lentes de Contato/parasitologia , Curcuma/química , Curcumina/farmacologia , Extratos Vegetais/farmacologia , Plásticos , Poliestirenos , Rizoma/química , TrofozoítosRESUMO
Diseases caused by pathogenic free-living amoebae include primary amoebic meningoencephalitis (Naegleria fowleri), granulomatous amoebic encephalitis (Acanthamoeba spp.), Acanthamoeba keratitis, and Balamuthia amoebic encephalitis (Balamuthia mandrillaris). Each of these are difficult to treat and have high morbidity and mortality rates due to lack of effective therapeutics. Since repurposing drugs is an ideal strategy for orphan diseases, we conducted a high throughput phenotypic screen of 12,000 compounds from the Calibr ReFRAME library. We discovered a total of 58 potent inhibitors (IC50 <1 µM) against N. fowleri (n = 19), A. castellanii (n = 12), and B. mandrillaris (n = 27) plus an additional 90 micromolar inhibitors. Of these, 113 inhibitors have never been reported to have activity against Naegleria, Acanthamoeba or Balamuthia. Rapid onset of action is important for new anti-amoeba drugs and we identified 19 compounds that inhibit N. fowleri in vitro within 24 hours (halofuginone, NVP-HSP990, fumagillin, bardoxolone, belaronib, and BPH-942, solithromycin, nitracrine, quisinostat, pabinostat, pracinostat, dacinostat, fimepinostat, sanguinarium, radicicol, acriflavine, REP3132, BC-3205 and PF-4287881). These compounds inhibit N. fowleri in vitro faster than any of the drugs currently used for chemotherapy. The results of these studies demonstrate the utility of phenotypic screens for discovery of new drugs for pathogenic free-living amoebae, including Acanthamoeba for the first time. Given that many of the repurposed drugs have known mechanisms of action, these compounds can be used to validate new targets for structure-based drug design.
Assuntos
Amebíase/tratamento farmacológico , Amebicidas/farmacologia , Reposicionamento de Medicamentos/métodos , Ensaios de Triagem em Larga Escala/métodos , Acanthamoeba/efeitos dos fármacos , Balamuthia mandrillaris/efeitos dos fármacos , Bases de Dados de Produtos Farmacêuticos , Naegleria fowleri/efeitos dos fármacos , Doenças Negligenciadas/tratamento farmacológico , Bibliotecas de Moléculas PequenasRESUMO
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.