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1.
Parasitol Res ; 123(4): 180, 2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38592544

RESUMEN

Because of recent reports of praziquantel resistance in schistosome infections, there have been suggestions to employ ivermectin as a possible alternative, especially as its chemical composition is different from that of praziquantel, so cross-resistance is not expected. In order to ascertain possible damage and elimination of worms, we used ivermectin by oral gavage in infected mice, at a high dose (30.1 mg/kg, bordering toxicity). We also tested the efficacy of the drug at various times postinfection (PI), to check on possible effect on young and mature stages of the parasites. Thus, we treated mice on days 21 and 22 or on days 41 and 42 and even on days 21, 22, 41, and 42 PI. None of the treatment regimens resulted in cure rates or signs of lessened pathology in the mice. We also compared the effect of ivermectin to that of artemisone, an artemisinin derivative which had served us in the past as an effective anti-schistosome drug, and there was a stark difference in the artemisone's efficacy compared to that of ivermectin; while ivermectin was not effective, artemisone eliminated most of the worms, prevented egg production and granulomatous inflammatory response. We assume that the reported lack of activity of ivermectin, in comparison with praziquantel and artemisinins, originates from the difference in their mode of action. In wake of our results, we suggest that ivermectin is not a suitable drug for treatment of schistosomiasis.


Asunto(s)
Artemisininas , Schistosomatidae , Esquistosomiasis , Animales , Ratones , Praziquantel/uso terapéutico , Ivermectina/uso terapéutico , Esquistosomiasis/tratamiento farmacológico
2.
Glob Chall ; 7(12): 2300030, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38094863

RESUMEN

Employing new therapeutic indications for drugs that are already approved for human use has obvious advantages, including reduced costs and timelines, because some routine steps of drug development and regulation are not required. This work concentrates on the redirection of artemisinins (ARTS) that already are approved for clinical use, or investigated, for malaria treatment. Several mechanisms of action are suggested for ARTS, among which only a few have been successfully examined in vivo, mainly the induction of oxidant stress and anti-inflammatory effects. Despite these seemingly contradictory effects, ARTS are proposed for repurposing in treatment of inflammatory disorders and diverse types of diseases caused by viral, bacterial, fungal, and parasitic infections. When pathogens are treated the expected outcome is diminution of the causative agents and/or their inflammatory damage. In general, repurposing ARTS is successful in only a very few cases, specifically when a valid mechanism can be targeted using an additional therapeutic agent and appropriate drug delivery. Investigation of repurposing should include optimization of drug combinations followed by examination in relevant cell lines, organoids, and animal models, before moving to clinical trials.

3.
Int J Parasitol Drugs Drug Resist ; 16: 148-154, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34116478

RESUMEN

Transdermal drug delivery avoids complications related to oral or parenteral delivery - the need for sterility, contamination, gastrointestinal side effects, patient unconsciousness or nausea and compliance. For malaria treatment, we demonstrate successful novel transdermal delivery of artemisone (ART) and artesunate. The incorporation of ART into a microemulsion (ME) overcomes the limitations of the lipophilic drug and provides high transcutaneous bioavailability. ART delivery to the blood (above 500 ng/ml) was proved by examining the sera from treated mice, using a bioassay in cultured Plasmodium falciparum. Skin spraying of ART-ME eliminated P. berghei ANKA in an infected mouse model of cerebral malaria (CM) and prevented CM, even after a late treatment with a relatively small amount of ART (13.3 mg/kg). For comparison, the artesunate (the most used commercial artemisinin) formulation was prepared as ART. However, ART-ME was about three times more efficient than artesunate-ME. The solubility and stability of ART in the ME, taken together with the successful transdermal delivery leading to animal recovery, suggest this formulation as a potential candidate for transdermal treatment of malaria.


Asunto(s)
Antimaláricos , Artemisininas , Malaria Cerebral , Animales , Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , Artesunato , Humanos , Malaria Cerebral/tratamiento farmacológico , Ratones , Plasmodium berghei
4.
Artículo en Inglés | MEDLINE | ID: mdl-33558284

RESUMEN

Artemisone (ART) has been successfully tested in vitro and in animal models against several diseases. However, its poor aqueous solubility and limited chemical stability are serious challenges. We developed a self-microemulsifying drug delivery system (SMEDDS) that overcomes these limitations. Here, we demonstrate the efficacy of this formulation against experimental cerebral malaria in mice and the impact of its administration using different routes (gavage, intranasal delivery, and parenteral injections) and frequency on the efficacy of the treatment. The minimal effective daily oral dose was 20 mg/kg. We found that splitting a dose of 20 mg/kg ART given every 24 h, by administering two doses of 10 mg/kg each every 12 h, was highly effective and gave far superior results compared to 20 mg/kg once daily. We obtained the best results with nasal treatment; oral treatment was ranked second, and the least effective route of administration was intraperitoneal injection. A complete cure of experimental cerebral malaria could be achieved through choosing the optimal route of application, dose, and dosing interval. Altogether, the developed formulation combines easy manufacturing with high stability and could be a successful and very versatile carrier for the delivery of ART in the treatment of human severe malaria.


Asunto(s)
Sistemas de Liberación de Medicamentos , Malaria Cerebral , Administración Oral , Animales , Artemisininas , Disponibilidad Biológica , Emulsiones , Malaria Cerebral/tratamiento farmacológico , Ratones , Tamaño de la Partícula , Solubilidad
5.
Bioorg Chem ; 102: 104069, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32683179

RESUMEN

Cationic molecules are found in abundance as antimicrobial agents with a well-defined mechanism of action and significant therapeutic benefits. Quaternary ammonium-containing compounds are frequently employed due to their facile synthesis and tunable properties. Over time, however, bacterial resistance to these compounds has become a significant obstacle. We report here a series of asymmetric trisalkylamine cyclopropenium cationic derivatives as chemical isosteres of quaternary ammonium compounds, capable of strong antimicrobial activity and overcoming microbial resistance. These small molecules were prepared by one-pot reaction of tetrachlorocyclopropene (TCC) with unhindered secondary amines in the presence of Hünig's base. In this work we describe the synthesis, purification, and characterization of five trisamino-cyclopropenium derivatives and confirm their structures by spectral analysis and mass-spectrometry. Three of the compounds displayed considerable antimalarial activity (IC50 < 0.1 µM) without demonstrating significant toxic effects in vitro (TC50 > 1 µM). This class of cyclopropenium-based compounds provides an opening for the discovery of potent and non-toxic antimicrobial agents.


Asunto(s)
Aminas/farmacología , Antiinfecciosos/farmacología , Ciclopropanos/farmacología , Plasmodium falciparum/efectos de los fármacos , Aminas/síntesis química , Aminas/química , Antiinfecciosos/síntesis química , Antiinfecciosos/química , Cationes/síntesis química , Cationes/química , Cationes/farmacología , Línea Celular , Ciclopropanos/síntesis química , Ciclopropanos/química , Humanos , Concentración 50 Inhibidora , Malaria/tratamiento farmacológico , Malaria/parasitología , Staphylococcus epidermidis/efectos de los fármacos
6.
Pharmaceutics ; 12(6)2020 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-32503130

RESUMEN

Artemisone is an innovative artemisinin derivative with applications in the treatment of malaria, schistosomiasis and other diseases. However, its low aqueous solubility and tendency to degrade after solubilisation limits the translation of this drug into clinical practice. We developed a self-microemulsifying drug delivery system (SMEDDS), which is easy to produce (simple mixing) with a high drug load. In addition to known pharmaceutical excipients (Capmul MCM, Kolliphor HS15, propylene glycol), we identified Polysorb ID 46 as a beneficial new additional excipient. The physicochemical properties were characterized by dynamic light scattering, conductivity measurements, rheology and electron microscopy. High storage stability, even at 30 °C, was achieved. The orally administrated artemisone SMEDDS formulation was highly active in vivo in S. mansoni infected mice. Thorough elimination of the adult worms, their eggs and prevention of the deleterious granuloma formation in the livers of infected mice was observed even at a relatively low dose of the drug. The new formulation has a high potential to accelerate the clinical use of artemisone in schistosomiasis and malaria.

7.
Front Pharmacol ; 11: 846, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32595499

RESUMEN

Malaria caused by Plasmodium falciparum causes numerous cases of morbidity with about 400,000 deaths yearly owing, mainly, to inflammation leading to cerebral malaria (CM). CM conventionally is treated by repetitive administration of anti-plasmodial drugs and supportive non-specific drugs, for about a week. A mouse model of CM caused by Plasmodium berghei ANKA, in which brain and systemic clinical pathologies occur followed by sudden death within about a week, was used to study the effect of artemisone, a relatively new artemisinin, within an injectable pasty polymer formulated for its controlled release. The parasites were exposed to the drug over several days at a non-toxic concentrations for the mice but high enough to affect the parasites. Artemisone was also tested in cultures of bacteria, cancer cells and P. falciparum to evaluate the specificity and suitability of these cells for examining the release of artemisone from its carrier. Cultures of P. falciparum were the most suitable. Artemisone released from subcutaneous injected poly(sebacic acid-ricinoleic acid) (PSARA) pasty polymer, reduced parasitemias in infected mice, prolonged survival and prevented death in most of the infected mice. Successful prophylactic treatment before infection proved that there was a slow release of the drug for about a week, which contrasts with the three hour half-life that occurs after injection of just the drug. Treatment with artemisone within the polymer, even at a late stage of the disease, helped to prevent or, at least, delay accompanying severe symptoms. In some cases, treatment prevented death of CM and the mice died later of anemia. Postponing the severe clinical symptoms is also beneficial in cases of human malaria, giving more time for an appropriate diagnosis and treatment before severe symptoms appear. The method presented here may also be useful for combination therapy of anti-plasmodial and immunomodulatory drugs.

8.
Biomacromolecules ; 18(10): 3215-3221, 2017 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-28820944

RESUMEN

Achieving high drug loading capacity and controlling drug delivery are two main challenges related to drug carriers. In this study, polymeric macroporous sponges with very high pore volume and large porosity are introduced as a new-type of drug carrier. Due to the high pore volume (285 and 166 cm3/g for the sponges with densities of 3.5 and 6.0 mg/cm3, respectively), the sponges exhibit very high drug loading capacities with average values of 1870 ± 114 and 2697 ± 73 mg/g in the present study, which is much higher than the meso and microporous drug carriers (<1500 mg/g). In order to control the release profiles, an additional poly(p-xylylene) (PPX) coating was deposited by chemical vapor deposition on the drug loaded sponge. Consequently, Artemisone (ART) release in the aqueous medium could be retarded, depending on the density of the sponge and the thickness of the coating. In future, the new 3D polymeric sponges would be highly beneficial as drug carriers for the programmed release of drugs for treatment of chronic diseases.


Asunto(s)
Artemisininas/química , Portadores de Fármacos/química , Liberación de Fármacos , Polímeros/química , Porosidad , Volatilización , Xilenos/química
9.
Int J Parasitol Drugs Drug Resist ; 7(2): 241-247, 2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-28511056

RESUMEN

The current treatment of schistosomiasis is based on the anti-helminthic drug praziquantel (PZQ). PZQ affects only the adult stages of schistosomes. In addition, resistance to PZQ is emerging. We suggest a drug, which could serve as a potential alternative or complement to PZQ, and as a means of treating infections at earlier, pre-granuloma stage. Derivatives of the peroxidic antimalarial drug artemisinin have been indicated as alternatives, because both plasmodia and schistosomes are blood-feeding parasites. The mechanism of action of artemisinins is related to oxidative effects of the artemisinins on intracellular reductants leading to formation of cytotoxic reactive oxygen species. We used artemisone, which has improved pharmacokinetics and anti-plasmodial activity, and reduced toxicity compared to other artemisinins in clinical use against malaria. We infected adult mice by subcutaneous injection of S. mansoni cercariae (about 200) and treated them at various times post infection by the following methods: i. artemisone suspension administered by gavage (400-450 mg/kg); ii. subcutaneous injection of a gel containing a known concentration of artemisone (115-120 mg/kg); iii. subcutaneous insertion of the drug incorporated in a solid polymer (56-60 mg/kg); iv. intraperitoneal injection of the drug solubilized in DMSO (115-120 mg/kg). Drug administration in polymers was performed to enable slow release of the artemisone that was verified in vivo and in vitro bioassays using drug-sensitive malaria parasites. We found superior strong anti-schistosome effects up to a total reduction of worm number, mainly following repetitive treatments with the drug absorbed in the polymers (73.1% and 95.9% reduction in mice treated with artemisone in gel 7 and 14, and 21, 28 and 35 days post infection, respectively). The results indicate that artemisone has a potent anti-schistosome activity. Its main importance in this context is its effectiveness in treating hosts harboring juvenile schistosomes, before egg-deposition and induction of deleterious immune responses.


Asunto(s)
Antihelmínticos/administración & dosificación , Artemisininas/administración & dosificación , Preparaciones de Acción Retardada/administración & dosificación , Schistosoma mansoni/efectos de los fármacos , Esquistosomiasis mansoni/tratamiento farmacológico , Administración Oral , Animales , Modelos Animales de Enfermedad , Inyecciones Intraperitoneales , Inyecciones Subcutáneas , Ratones , Resultado del Tratamiento
10.
Parasit Vectors ; 10(1): 117, 2017 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-28249591

RESUMEN

BACKGROUND: Cerebral malaria (CM) is a leading cause of malarial mortality resulting from infection by Plasmodium falciparum. Treatment commonly involves adjunctive care and injections or transfusion of artemisinins. All artemisinins that are in current use are metabolized to dihydroxyartemisinin (DHA), to which there is already some parasite resistance. We used artemisone, a derivative that does not convert to DHA, has improved pharmacokinetics and anti-plasmodial activity and is also anti-inflammatory (an advantage given the immunopathological nature of CM). METHODS: We examined controlled artemisone release from biodegradable polymers in a mouse CM model. This would improve treatment by exposing the parasites for a longer period to a non-toxic drug concentration, high enough to eliminate the pathogen and prevent CM. The preparations were inserted into mice as prophylaxis, early or late treatment in the disease course. RESULTS: The most efficient formulation was a rigid polymer, containing 80 mg/kg artemisone, which cured all of the mice when used as early treatment and 60% of the mice when used as a very late treatment (at which stage all control mice would die of CM within 24 h). In those mice that were not completely cured, relapse followed a latent period of more than seven days. Prophylactic treatment four days prior to the infection prevented CM. We also measured the amount of artemisone released from the rigid polymers using a bioassay with cultured P. falciparum. Significant amounts of artemisone were released throughout at least ten days, in line with the in vivo prophylactic results. CONCLUSIONS: Overall, we demonstrate, as a proof-of-concept, a controlled-sustained release system of artemisone for treatment of CM. Mice were cured or if treated at a very late stage of the disease, depicted a delay of a week before death. This delay would enable a considerable time window for exact diagnosis and appropriate additional treatment. Identical methods could be used for other parasites that are sensitive to artemisinins (e.g. Toxoplasma gondii and Neospora caninum).


Asunto(s)
Antimaláricos/administración & dosificación , Artemisininas/administración & dosificación , Preparaciones de Acción Retardada/administración & dosificación , Malaria Cerebral/tratamiento farmacológico , Animales , Antimaláricos/química , Artemisininas/farmacocinética , Preparaciones de Acción Retardada/farmacocinética , Modelos Animales de Enfermedad , Humanos , Malaria Cerebral/parasitología , Masculino , Ratones , Ratones Endogámicos C57BL
11.
Glob Chall ; 1(2): 1600011, 2017 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-31565264

RESUMEN

A programmable release system with wide range of release profiles of the antimalarial artemisone (ART) from fibrous nanocarriers (NFN) is presented. This is achieved following a new paradigm of using ART-loaded NFN in infusion system of hydrophobic drug eluting nanocarriers, adapted to clinical applications. Very importantly, under these conditions ART did not degrade as it was observed in solution.

12.
Vet Parasitol ; 219: 66-70, 2016 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-26921042

RESUMEN

Neospora caninum, the causative agent of bovine neosporosis is the major cause of abortion in cattle worldwide. The principal route of transmission is via in utero infection of the offspring. Congenitally-infected dams remain persistently infected for life and might undergo abortions in consecutive pregnancies. In the present study, the effect of N. caninum in chronic and congenital infection was examined. CD1 mice were infected intra-peritoneally with live tachyzoites of the NcIs491 isolate, while non-infected mice served as a control. There were no clinical signs of infection observed following inoculation, but high titers of specific anti- N. caninum antibodies were detected. A month after infection, when chronic-infection was established, mice were mated. Fertility, litter size and mortality rate were monitored within two generations of four consecutive pregnancies. During a nine months period of the study all females maintained high level of antibodies, while the non- infected control mice remained seronegative. There was no difference in the fertility rate of the dams, or in the litter size of infected and control mice. Mortality of offspring of the first and second generations of the infected dams was observed within the two first weeks of life. The vertical transmission was analyzed by PCR assay of offspring brains. PCR positive results were found in all 13 litters of the first generation tested during four consecutive pregnancies. The rate of vertical transmission slightly decreased in successive pregnancies being 74.2%, 59.5%, 48.1% and 40% for the first to fourth pregnancies respectively. In the second generation 21 out of 28 litters were found positive and the overall rate of vertical transmission was 28.5%. In chronically and congenitally infected dams N. caninum infection was maintained during all successive pregnancies for about 9 months. The results show that CD-1 outbred mice are a suitable model for studying chronic and congenital neosporosis.


Asunto(s)
Coccidiosis/congénito , Coccidiosis/transmisión , Transmisión Vertical de Enfermedad Infecciosa , Animales , Anticuerpos Antiprotozoarios/sangre , Enfermedad Crónica , Coccidiosis/sangre , Modelos Animales de Enfermedad , Femenino , Ratones , Neospora/fisiología , Reacción en Cadena de la Polimerasa , Embarazo
13.
Theranostics ; 6(2): 167-76, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26877776

RESUMEN

Cerebral malaria (CM) is a major cause of death of Plasmodium falciparum infection. Misdiagnosis of CM often leads to treatment delay and mortality. Conventional brain imaging technologies are rarely applicable in endemic areas. Here we address the unmet need for a simple, non-invasive imaging methodology for early diagnosis of CM. This study presents the diagnostic and therapeutic monitoring using liposomes containing the FDA-approved fluorescent dye indocyanine green (ICG) in a CM murine model. Increased emission intensity of liposomal ICG was demonstrated in comparison with free ICG. The Liposomal ICG's emission was greater in the brains of the infected mice compared to naïve mice and drug treated mice (where CM was prevented). Histological analyses suggest that the accumulation of liposomal ICG in the cerebral vasculature is due to extensive uptake mediated by activated phagocytes. Overall, liposomal ICG offers a valuable diagnostic tool and a biomarker for effectiveness of CM treatment, as well as other diseases that involve inflammation and blood vessel occlusion.


Asunto(s)
Colorantes Fluorescentes/farmacocinética , Verde de Indocianina/farmacocinética , Liposomas/farmacocinética , Malaria Cerebral/diagnóstico , Animales , Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , Línea Celular , Colorantes Fluorescentes/química , Verde de Indocianina/química , Liposomas/química , Malaria Cerebral/tratamiento farmacológico , Masculino , Ratones , Ratones Endogámicos C57BL , Neuroimagen/métodos
14.
Macromol Rapid Commun ; 37(3): 251-6, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26572088

RESUMEN

PEG400 (polyethylene glycol, MW 400) biscyanoacrylate is synthesized and copolymerized with 2-octyl cyanoacrylate for potential use as bioadhesive. PEG400 biscyanoacrylate is synthesized from the esterification of anthracenyl cyanoacrylic acid where the anthracene unit serves as vinyl-protecting group. Copolymerization increases the plasticity, mechanical strength, and resilience of the resulted polymer as determined by dynamic mechanical analysis. Peeling test confirms its superior bioadhesive properties. Surface morphology is characterized by SEM imaging. The formulations are cytocompatible and safe. This cyanoacrylate composition may provide improved bioadhesive cyanoacrylates.


Asunto(s)
Reactivos de Enlaces Cruzados/química , Cianoacrilatos/química , Polietilenglicoles/química , Adhesivos Tisulares/farmacología , Muerte Celular/efectos de los fármacos , Línea Celular , Cianoacrilatos/síntesis química , Elasticidad , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Peso Molecular , Reología , Viscosidad
15.
Nanomedicine ; 11(5): 1057-64, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25791809

RESUMEN

Intraoperative ureter identification can assist in the prevention of ureteral injury and consequently improve surgery outcomes. Our aim was to take advantage of the altered pharmacokinetics of liposomal indocyanine green (ICG), the only FDA-approved near-infrared (NIR) dye, for imaging of ureters during surgeries. ICG was passively adsorbed to liposomes. NIR whole mice body and isolated tissue imaging were used to study liposomal ICG properties vs. free ICG. In vivo, the urinary bladder could be clearly observed in most of the liposome-treated mice. Liposomal encapsulation of ICG enhanced ureteral emission up to 1.9 fold compared to free ICG (P<0.01). Increase in liposomal micropolarity and microviscosity and differential scanning calorimetry supported ICG localization within the liposomal bilayer. Our findings suggest that liposomal ICG could be utilized for ureteral imaging intra-operatively, thus potentially improving surgical outcomes. FROM THE CLINICAL EDITOR: Iatrogenic ureteral injury is a serious complication of abdominal surgery and intra-operative recognition of the ureters is usually the best method of injury prevention. In this article, the authors developed liposomal indocyanine green, which could be excreted via the urinary system and investigated its in-vivo use in mice.


Asunto(s)
Colorantes/administración & dosificación , Verde de Indocianina/administración & dosificación , Imagen Óptica/métodos , Uréter/patología , Vejiga Urinaria/patología , Animales , Colorantes/farmacocinética , Femenino , Verde de Indocianina/farmacocinética , Rayos Infrarrojos , Liposomas , Ratones , Uréter/lesiones , Vejiga Urinaria/lesiones
16.
Biomed Res Int ; 2014: 292471, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25126550

RESUMEN

Cerebral malaria (CM) is a severe complication of and a leading cause of death due to Plasmodium falciparum infection. CM is likely the result of interrelated events, including mechanical obstruction due to parasite sequestration in the microvasculature, and upregulation of Th1 immune responses. In parallel, blood-brain-barrier (BBB) breakdown and damage or death of microglia, astrocytes, and neurons occurs. We found that a novel formulation of a liposome-encapsulated glucocorticosteroid, ß-methasone hemisuccinate (nSSL-BMS), prevents experimental cerebral malaria (ECM) in a murine model and creates a survival time-window, enabling administration of an antiplasmodial drug before severe anemia develops. nSSL-BMS treatment leads to lower levels of cerebral inflammation, expressed by altered levels of corresponding cytokines and chemokines. The results indicate the role of integrated immune responses in ECM induction and show that the new steroidal nanodrug nSSL-BMS reverses the balance between the Th1 and Th2 responses in malaria-infected mice so that the proinflammatory processes leading to ECM are prevented. Overall, because of the immunopathological nature of CM, combined immunomodulator/antiplasmodial treatment should be considered for prevention/treatment of human CM and long-term cognitive damage.


Asunto(s)
Betametasona/administración & dosificación , Sistemas de Liberación de Medicamentos , Inflamación/tratamiento farmacológico , Malaria Cerebral/tratamiento farmacológico , Nanopartículas/administración & dosificación , Animales , Betametasona/química , Barrera Hematoencefálica/efectos de los fármacos , Quimiocinas/biosíntesis , Modelos Animales de Enfermedad , Humanos , Inflamación/metabolismo , Inflamación/patología , Liposomas/administración & dosificación , Liposomas/química , Malaria Cerebral/inducido químicamente , Malaria Cerebral/patología , Ratones , Nanopartículas/química , Plasmodium berghei/patogenicidad , Plasmodium falciparum/patogenicidad , Balance Th1 - Th2/efectos de los fármacos
17.
Vet Parasitol ; 205(1-2): 85-91, 2014 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-24986462

RESUMEN

Neosporosis caused by caused by the apicomplexan parasite Neospora caninum is one of the major causes of infectious abortion in bovines worldwide. A long-term prospective study was performed in a dairy herd endemic for N. caninum in order to analyze the impact of neosporosis on the proportion of aborting cows. A total of 1078 pregnant cows were tested for presence of antibodies and the proportion of abortions was calculated. The overall seroprevalence of N. caninum found in the herd was 35.5%. The percentage of abortions in seropositive cows was 3 times higher than in their seronegative counterparts (21.6 and 7.3%, respectively). No statistically significant association was found between the antibody level of positive during pregnancy and the proportion of aborting cows. However, 41.2% of the dams with antibody titers of 1:12,800 aborted. The risk of abortion for such dams was 2.7 times higher than for other seropositive cows which had lower titers of antibodies (p=0.0072). In the follow-up examinations of the seropositive cows during several pregnancies, the overall percent of abortions observed was significantly higher than in seronegative individuals (49.3 and 16.9%, respectively; p<0.0001). Moreover, the proportion of repetitive abortion observed was 5 to 1 (17.4 and 3.5%) in seropositive and seronegative dams, respectively (p<0.001). The rate of vertical transmission in positive dams was 61.0% and it appeared to be directly associated with antibody levels: the higher the titer in the dams during pregnancy, the higher the percentage of sero-positivity in their calves. Increased proportion of abortions was observed in seropositive cows both in summer and winter in comparison with spring and autumn. It was found that in seropositive cows, an increased number of pregnancies, which was directly related to the age of the dam, has been associated with an increased number of abortions.


Asunto(s)
Enfermedades de los Bovinos/parasitología , Coccidiosis/veterinaria , Complicaciones Parasitarias del Embarazo/veterinaria , Aborto Veterinario/parasitología , Animales , Bovinos , Enfermedades de los Bovinos/patología , Coccidiosis/parasitología , Coccidiosis/patología , Femenino , Embarazo , Complicaciones Parasitarias del Embarazo/patología
18.
Antimicrob Agents Chemother ; 58(8): 4745-54, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24913162

RESUMEN

The decreasing effectiveness of antimalarial therapy due to drug resistance necessitates constant efforts to develop new drugs. Artemisinin derivatives are the most recent drugs that have been introduced and are considered the first line of treatment, but there are already indications of Plasmodium falciparum resistance to artemisinins. Consequently, drug combinations are recommended for prevention of the induction of resistance. The research here demonstrates the effects of novel combinations of the new artemisinin derivative, artemisone, a recently described 10-alkylamino artemisinin derivative with improved antimalarial activity and reduced neurotoxicity. We here investigate its ability to kill P. falciparum in a high-throughput in vitro assay and to protect mice against lethal cerebral malaria caused by Plasmodium berghei ANKA when used alone or in combination with established antimalarial drugs. Artemisone effects against P. falciparum in vitro were synergistic with halofantrine and mefloquine, and additive with 25 other drugs, including chloroquine and doxycycline. The concentrations of artemisone combinations that were toxic against THP-1 cells in vitro were much higher than their effective antimalarial concentration. Artemisone, mefloquine, chloroquine, or piperaquine given individually mostly protected mice against cerebral malaria caused by P. berghei ANKA but did not prevent parasite recrudescence. Combinations of artemisone with any of the other three drugs did completely cure most mice of malaria. The combination of artemisone and chloroquine decreased the ratio of proinflammatory (gamma interferon, tumor necrosis factor) to anti-inflammatory (interleukin 10 [IL-10], IL-4) cytokines in the plasma of P. berghei-infected mice. Thus, artemisone in combinations with other antimalarial drugs might have a dual action, both killing parasites and limiting the potentially deleterious host inflammatory response.


Asunto(s)
Antimaláricos/farmacología , Artemisininas/farmacología , Malaria Cerebral/tratamiento farmacológico , Plasmodium berghei/efectos de los fármacos , Plasmodium falciparum/efectos de los fármacos , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Cloroquina/farmacología , Doxiciclina/farmacología , Sinergismo Farmacológico , Quimioterapia Combinada , Eritrocitos/efectos de los fármacos , Eritrocitos/parasitología , Humanos , Interleucina-10/antagonistas & inhibidores , Interleucina-10/biosíntesis , Interleucina-4/antagonistas & inhibidores , Interleucina-4/biosíntesis , Malaria Cerebral/inmunología , Malaria Cerebral/parasitología , Mefloquina/farmacología , Ratones , Ratones Endogámicos C57BL , Monocitos/citología , Monocitos/efectos de los fármacos , Pruebas de Sensibilidad Parasitaria , Fenantrenos/farmacología , Plasmodium berghei/fisiología , Plasmodium falciparum/fisiología
19.
Exp Parasitol ; 135(4): 690-4, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24184077

RESUMEN

Artemisone was evaluated, in in vitro and in vivo, for control of bovine babesiosis caused by Babesia bigemina and Babesia bovis parasites. In vitro, artemisone reduced parasitemia in a dose-dependent manner: the inhibitory effects increased gradually, reaching a maximum inhibition of 99.6% and 86.4% for B. bigemina and B. bovis, respectively 72 h after initiation of treatment with initial parasitemia of 0.5%. In calves infected with either B. bigemina or B. bovis artemisone treatment was well tolerated and prevented development of acute babesiosis in all animals except for one B. bovis-infected calf. The treatment did not eliminate all blood parasites, and recovered animals carried a persistent low-level infection. Treatment with artemisone may be useful as an alternative drug for preventing the pathology that results from babesiosis, without interfering with acquired immune protection following recovery from an acute babesiosis infection or vaccination.


Asunto(s)
Antiprotozoarios/farmacología , Artemisininas/farmacología , Babesia/efectos de los fármacos , Babesiosis/veterinaria , Enfermedades de los Bovinos/prevención & control , Animales , Antiprotozoarios/uso terapéutico , Artemisininas/uso terapéutico , Babesia/crecimiento & desarrollo , Babesia/inmunología , Babesia bovis/efectos de los fármacos , Babesia bovis/crecimiento & desarrollo , Babesia bovis/inmunología , Babesiosis/inmunología , Babesiosis/prevención & control , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Relación Dosis-Respuesta a Droga , Concentración 50 Inhibidora , Parasitemia/inmunología , Parasitemia/prevención & control , Parasitemia/veterinaria , Distribución Aleatoria
20.
PLoS One ; 8(8): e72722, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23991146

RESUMEN

Cerebral malaria is the most severe complication of Plasmodium falciparum infection, and a leading cause of death in children under the age of five in malaria-endemic areas. We report high therapeutic efficacy of a novel formulation of liposome-encapsulated water-soluble glucocorticoid prodrugs, and in particular ß-methasone hemisuccinate (BMS), for treatment of experimental cerebral malaria (ECM), using the murine P. berghei ANKA model. BMS is a novel derivative of the potent steroid ß-methasone, and was specially synthesized to enable remote loading into nano-sterically stabilized liposomes (nSSL), to form nSSL-BMS. The novel nano-drug, composed of nSSL remote loaded with BMS, dramatically improves drug efficacy and abolishes the high toxicity seen upon administration of free BMS. nSSL-BMS reduces ECM rates in a dose-dependent manner and creates a survival time-window, enabling administration of an antiplasmodial drug, such as artemisone. Administration of artemisone after treatment with the nSSL-BMS results in complete cure. Treatment with BMS leads to lower levels of cerebral inflammation, demonstrated by changes in cytokines, chemokines, and cell markers, as well as diminished hemorrhage and edema, correlating with reduced clinical score. Administration of the liposomal formulation results in accumulation of BMS in the brains of sick mice but not of healthy mice. This steroidal nano-drug effectively eliminates the adverse effects of the cerebral syndrome even when the treatment is started at late stages of disease, in which disruption of the blood-brain barrier has occurred and mice show clear signs of neurological impairment. Overall, sequential treatment with nSSL-BMS and artemisone may be an efficacious and well-tolerated therapy for prevention of CM, elimination of parasites, and prevention of long-term cognitive damage.


Asunto(s)
Betametasona/uso terapéutico , Modelos Animales de Enfermedad , Liposomas , Malaria Cerebral/tratamiento farmacológico , Nanopartículas , Enfermedad Aguda , Animales , Secuencia de Bases , Betametasona/administración & dosificación , Cartilla de ADN , Malaria Cerebral/parasitología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos ICR , Plasmodium berghei/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa
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