-
PLoS Neglected Tropical Diseases Feb 2019Visceral leishmaniasis is a neglected parasitic disease with no vaccine available and its pharmacological treatment is reduced to a limited number of unsafe drugs. The...
BACKGROUND
Visceral leishmaniasis is a neglected parasitic disease with no vaccine available and its pharmacological treatment is reduced to a limited number of unsafe drugs. The scarce readiness of new antileishmanial drugs is even more alarming when relapses appear or the occurrence of hard-to-treat resistant strains is detected. In addition, there is a gap between the initial and late stages of drug development, which greatly delays the selection of leads for subsequent studies.
METHODOLOGY/PRINCIPAL FINDINGS
In order to address these issues, we have generated a red-shifted luminescent Leishmania infantum strain that enables long-term monitoring of parasite burden in individual animals with an in vivo limit of detection of 106 intracellular amastigotes 48 h postinfection. For this purpose, we have injected intravenously different infective doses (104-5x108) of metacyclic parasites in susceptible mouse models and the disease was monitored from initial times to 21 weeks postinfection. The emission of light from the target organs demonstrated the sequential parasite colonization of liver, spleen and bone marrow. When miltefosine was used as proof-of-concept, spleen weight parasite burden and bioluminescence values decreased significantly.
CONCLUSIONS
In vivo bioimaging using a red-shifted modified Leishmania infantum strain allows the appraisal of acute and chronic stage of infection, being a powerful tool for accelerating drug development against visceral leishmaniasis during both stages and helping to bridge the gap between early discovery process and subsequent drug development.
Topics: Animals; Antiprotozoal Agents; Disease Models, Animal; Drug Discovery; Female; Leishmania infantum; Leishmaniasis, Visceral; Luminescent Measurements; Luminescent Proteins; Mice; Mice, Inbred BALB C; Phosphorylcholine; Spleen
PubMed: 30763330
DOI: 10.1371/journal.pntd.0007133 -
International Journal of Molecular... Jan 2023Visceral leishmaniasis is a neglected vector-borne tropical disease caused by and that is endemic not only in East African countries, but also in Asia, regions of...
Visceral leishmaniasis is a neglected vector-borne tropical disease caused by and that is endemic not only in East African countries, but also in Asia, regions of South America and the Mediterranean Basin. For the pharmacological control of this disease, there is a limited number of old and, in general, poorly adherent drugs, with a multitude of adverse effects and low oral bioavailability, which favor the emergence of resistant pathogens. Pentavalent antimonials are the first-line drugs, but due to their misuse, resistant strains have emerged worldwide. Although these drugs have saved many lives, it is recommended to reduce their use as much as possible and replace them with novel and more friendly drugs. From a commercial collection of anti-infective drugs, we have recently identified nifuratel-a nitrofurantoin used against vaginal infections-as a promising repurposing drug against a mouse model of visceral leishmaniasis. In the present work, we have tested combinations of miltefosine-the only oral drug currently used against leishmaniasis-with nifuratel in different proportions, both in axenic amastigotes from bone marrow and in intracellular amastigotes from infected Balb/c mouse spleen macrophages, finding a potent synergy in both cases. In vivo evaluation of oral miltefosine/nifuratel combinations using a bioimaging platform has revealed the potential of these combinations for the treatment of this disease.
Topics: Animals; Female; Mice; Leishmaniasis, Visceral; Leishmania donovani; Nifuratel; Antiprotozoal Agents; Phosphorylcholine
PubMed: 36675150
DOI: 10.3390/ijms24021635 -
International Journal For Parasitology.... Aug 2018Increasing drug resistance towards first line antimony-derived compounds has forced the introduction of novel therapies in leishmaniasis endemic areas including...
Increasing drug resistance towards first line antimony-derived compounds has forced the introduction of novel therapies in leishmaniasis endemic areas including amphotericin B and miltefosine. However, their use is threatened by the emergence and spread of drug-resistant strains. In order to discover stage-dependent resistance genes, we have adapted the Cos-Seq approach through the introduction of macrophage infections in the pipeline. A L. infantum intracellular amastigote population complemented with a L. infantum cosmid library was submitted to increasing concentrations of miltefosine, amphotericin B and pentavalent antimonials in experimental infections of THP-1 cells. For each step of selection, amastigotes were extracted and cosmids were isolated and submitted to next-generation sequencing, followed by subsequent gene-enrichment analyses. Cos-Seq screen in amastigotes revealed four highly enriched loci for antimony, five for miltefosine and one for amphotericin B. Of these, a total of seven cosmids were recovered and tested for resistance in both promastigotes and amastigotes. Candidate genes within the pinpointed genomic regions were validated using single gene overexpression in wild-type parasites and/or gene disruption by means of a CRISPR-Cas9-based approach. This led to the identification and validation of a stage-independent antimony-resistance gene (LinJ.06.1010) coding for a putative leucine rich repeat protein and a novel amastigote-specific miltefosine-resistance gene (LinJ.32.0050) coding for a member of the SEC13 family of WD-repeat proteins. This study further reinforces the power of Cos-Seq approach to discover novel drug-resistance genes, some of which are life-stages specific.
Topics: Amphotericin B; Animals; Antimony; Antiprotozoal Agents; CRISPR-Cas Systems; Cosmids; Drug Resistance; Gene Library; High-Throughput Nucleotide Sequencing; Leishmania infantum; Leishmaniasis; Life Cycle Stages; Macrophages; Phosphorylcholine
PubMed: 29602064
DOI: 10.1016/j.ijpddr.2018.03.004 -
International Journal of Nanomedicine 2019Previous studies indicate that miltefosine (MFS) may be an alternative as an antifungal agent; however, it presents several adverse effects. Thus, the aim of this study...
INTRODUCTION AND OBJECTIVE
Previous studies indicate that miltefosine (MFS) may be an alternative as an antifungal agent; however, it presents several adverse effects. Thus, the aim of this study was to produce miltefosine-loaded alginate nanoparticles (MFS.Alg) for toxicity reduction to be used as an alternative for the treatment of cryptococcosis and candidiasis.
METHODS
Alginate nanoparticles were produced using the external emulsification/gelation method, and their physicochemical and morphological characteristics were analyzed. MFS encapsulation efficiency, release assay and toxicity on red blood cells and on larvae were assessed. The antifungal activity was evaluated using in vitro and in vivo larval models of infected with (SC5314 and IAL-40), H99 and ATCC 56990. The treatment efficacy was evaluated by survival curve, colony forming unit (CFU) counting and histopathological analysis.
RESULTS
MFS.Alg nanoparticles presented a mean size of 279.1±56.7 nm, a polydispersity index of 0.42±0.15 and a zeta potential of -39.7±5.2 mV. The encapsulation efficiency of MFS was 81.70±6.64%, and its release from the nanoparticles occurred in a sustained manner. MFS in alginate nanoparticles presented no hemolytic effect and no toxicity in larvae. Treatment with MFS.Alg extended the survival time of larvae infected with and . In addition, the fungal burden reduction was confirmed by CFU and histopathological data for all groups treated with 200 mg/Kg of MFS.Alg.
CONCLUSION
These results support the use of alginate-based drug delivery systems as carriers for MFS for drug toxicity reduction and control of the fungal infection in the in vivo model of .
Topics: Alginates; Animals; Antifungal Agents; Candida albicans; Candidiasis; Cryptococcosis; Drug Delivery Systems; Drug Liberation; Larva; Microbial Sensitivity Tests; Nanoparticles; Phosphorylcholine; Sheep
PubMed: 31371955
DOI: 10.2147/IJN.S205350 -
The New England Journal of Medicine Nov 2002There are 500,000 cases per year of visceral leishmaniasis, which occurs primarily in the Indian subcontinent. Almost all untreated patients die, and all the effective... (Clinical Trial)
Clinical Trial Comparative Study Randomized Controlled Trial
BACKGROUND
There are 500,000 cases per year of visceral leishmaniasis, which occurs primarily in the Indian subcontinent. Almost all untreated patients die, and all the effective agents have been parenteral. Miltefosine is an oral agent that has been shown in small numbers of patients to have a favorable therapeutic index for Indian visceral leishmaniasis. We performed a clinical trial in India comparing miltefosine with the most effective standard treatment, amphotericin B.
METHODS
The study was a randomized, open-label comparison, in which 299 patients 12 years of age or older received orally administered miltefosine (50 or 100 mg [approximately 2.5 mg per kilogram of body weight] daily for 28 days) and 99 patients received intravenously administered amphotericin B (1 mg per kilogram every other day for a total of 15 injections).
RESULTS
The groups were well matched in terms of age, weight, proportion with previous failure of treatment for leishmaniasis, parasitologic grade of splenic aspirate, and splenomegaly. At the end of treatment, splenic aspirates were obtained from 293 patients in the miltefosine group and 98 patients in the amphotericin B group. No parasites were identified, for an initial cure rate of 100 percent. By six months after the completion of treatment, 282 of the 299 patients in the miltefosine group (94 percent [95 percent confidence interval, 91 to 97]) and 96 of the 99 patients in the amphotericin B group (97 percent) had not had a relapse; these patients were classified as cured. Vomiting and diarrhea, generally lasting one to two days, occurred in 38 percent and 20 percent of the patients in the miltefosine group, respectively.
CONCLUSIONS
Oral miltefosine is an effective and safe treatment for Indian visceral leishmaniasis. Miltefosine may be particularly advantageous because it can be administered orally. It may also be helpful in regions where parasites are resistant to current agents.
Topics: Administration, Oral; Adolescent; Adult; Amphotericin B; Animals; Antiprotozoal Agents; Female; Humans; India; Infusions, Intravenous; Leishmania donovani; Leishmaniasis, Visceral; Male; Phosphorylcholine; Recurrence; Spleen
PubMed: 12456849
DOI: 10.1056/NEJMoa021556 -
Clinical and Experimental Immunology Aug 2018The role of helminth treatment in autoimmune diseases is growing constantly. Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease with challenging... (Comparative Study)
Comparative Study
The role of helminth treatment in autoimmune diseases is growing constantly. Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease with challenging treatment options. Tuftsin-phosphorylcholine (TPC) is a novel helminth-based compound that modulates the host immune network. This study was conducted to evaluate the potential value of TPC in ameliorating lupus nephritis in a murine model and specifically to compare the efficacy of TPC to the existing first-line therapy for SLE: corticosteroids (methylprednisolone). Lupus-prone NZBxW/F mice were treated with TPC (5 µg/mouse), methylprednisolone (MP; 5 mg/body weight) or phosphate-buffered saline (PBS) (control) three times per week once glomerulonephritis, defined as proteinuria of grade > 100 mg/dl, was established. Levels of anti-dsDNA autoantibodies were evaluated by enzyme-linked immunosorbent assay (ELISA), splenic cytokines were measured in vitro and the kidney microscopy was analysed following staining. TPC and MP treatments improved lupus nephritis significantly and prolonged survival in NZBxW/F mice. TPC-treated mice showed a significantly decreased level of proteinuria (P < 0·001) and anti-dsDNA antibodies (P < 0·001) compared to PBS-treated mice. Moreover, TPC and MP inhibited the production of the proinflammatory cytokines interferon IFN-γ, interleukin IL-1β and IL-6 (P < 0·001) and enhanced expression of the anti-inflammatory cytokine IL-10 (P < 0·001). Finally, microscopy analysis of the kidneys demonstrated that TPC-treated mice maintained normal structure equally to MP-treated mice. These data indicate that the small molecule named TPC hinders lupus development in genetically lupus-prone mice equally to methylprednisolone in most of the cases. Hence, TCP may be employed as a therapeutic potential for lupus nephritis.
Topics: Animals; Anti-Inflammatory Agents; Antibodies, Antinuclear; Cytokines; Disease Models, Animal; Drug Combinations; Female; Helminths; Humans; Inflammation Mediators; Kidney; Lupus Erythematosus, Systemic; Lupus Nephritis; Methylprednisolone; Mice; Mice, Inbred NZB; Phosphorylcholine; Tuftsin
PubMed: 29698559
DOI: 10.1111/cei.13137 -
Scientific Reports Aug 2018The growing drug resistance (DR) raises major concerns for the control of visceral leishmaniasis (VL), a neglected disease lethal in 95 percent of the cases if left...
The growing drug resistance (DR) raises major concerns for the control of visceral leishmaniasis (VL), a neglected disease lethal in 95 percent of the cases if left untreated. Resistance has rendered antimonials (SSG) obsolete in the Indian Sub-Continent (ISC) and the first miltefosine-resistant Leishmania donovani were isolated. New chemotherapeutic options are needed and novel compounds are being identified by high-throughput screening (HTS). HTS is generally performed with old laboratory strains such as LdBOB and we aimed here to validate the activity of selected compounds against recent clinical isolates. In this academic/industrial collaboration, 130 compounds from the GSK "Leishbox" were screened against one SSG-sensitive and one SSG-resistant strain of L. donovani recently isolated from ISC patients, using an intracellular assay of L. donovani-infected THP1-derived macrophages. We showed that only 45% of the compounds were active in both clinical isolates and LdBOB. There were also different compound efficiencies linked to the SSG susceptibility background of the strains. In addition, our results suggested that the differential susceptibility profiles were chemical series-dependent. In conclusion, we demonstrate the potential value of including clinical isolates (as well as resistant strains) in the HTS progression cascade.
Topics: Antiprotozoal Agents; Drug Discovery; Drug Resistance; Humans; Leishmania donovani; Leishmaniasis, Visceral; Macrophages; Phosphorylcholine; THP-1 Cells
PubMed: 30082744
DOI: 10.1038/s41598-018-30040-5 -
International Journal of Oral Science Jun 2018Biofilms at the tooth-restoration bonded interface can produce acids and cause recurrent caries. Recurrent caries is a primary reason for restoration failures. The...
Biofilms at the tooth-restoration bonded interface can produce acids and cause recurrent caries. Recurrent caries is a primary reason for restoration failures. The objectives of this study were to synthesize a novel bioactive dental bonding agent containing dimethylaminohexadecyl methacrylate (DMAHDM) and 2-methacryloyloxyethyl phosphorylcholine (MPC) to inhibit biofilm formation at the tooth-restoration margin and to investigate the effects of water-aging for 6 months on the dentin bond strength and protein-repellent and antibacterial durability. A protein-repellent agent (MPC) and antibacterial agent (DMAHDM) were added to a Scotchbond multi-purpose (SBMP) primer and adhesive. Specimens were stored in water at 37 °C for 1, 30, 90, or 180 days (d). At the end of each time period, the dentin bond strength and protein-repellent and antibacterial properties were evaluated. Protein attachment onto resin specimens was measured by the micro-bicinchoninic acid approach. A dental plaque microcosm biofilm model was used to test the biofilm response. The SBMP + MPC + DMAHDM group showed no decline in dentin bond strength after water-aging for 6 months, which was significantly higher than that of the control (P < 0.05). The SBMP + MPC + DMAHDM group had protein adhesion that was only 1/20 of that of the SBMP control (P < 0.05). Incorporation of MPC and DMAHDM into SBMP provided a synergistic effect on biofilm reduction. The antibacterial effect and resistance to protein adsorption exhibited no decrease from 1 to 180 d (P > 0.1). In conclusion, a bonding agent with MPC and DMAHDM achieved a durable dentin bond strength and long-term resistance to proteins and oral bacteria. The novel dental bonding agent is promising for applications in preventive and restorative dentistry to reduce biofilm formation at the tooth-restoration margin.
Topics: Anti-Infective Agents; Biofilms; Dental Bonding; Dentin-Bonding Agents; Materials Testing; Methacrylates; Phosphorylcholine; Resin Cements; Shear Strength; Surface Properties; Water
PubMed: 29925870
DOI: 10.1038/s41368-018-0019-9 -
Acta Biomaterialia Oct 2015The structural and optical properties of clinically biocompatible, cell-free hydrogels comprised of synthetically cross-linked and moulded recombinant human collagen...
The structural and optical properties of clinically biocompatible, cell-free hydrogels comprised of synthetically cross-linked and moulded recombinant human collagen type III (RHCIII) with and without the incorporation of 2-methacryloyloxyethyl phosphorylcholine (MPC) were assessed using transmission electron microscopy (TEM), X-ray scattering, spectroscopy and refractometry. These findings were examined alongside similarly obtained data from 21 human donor corneas. TEM demonstrated the presence of loosely bundled aggregates of fine collagen filaments within both RHCIII and RHCIII-MPC implants, which X-ray scattering showed to lack D-banding and be preferentially aligned in a uniaxial orientation throughout. This arrangement differs from the predominantly biaxial alignment of collagen fibrils that exists in the human cornea. By virtue of their high water content (90%), very fine collagen filaments (2-9 nm) and lack of cells, the collagen hydrogels were found to transmit almost all incident light in the visible spectrum. They also transmitted a large proportion of UV light compared to the cornea which acts as an effective UV filter. Patients implanted with these hydrogels should be cautious about UV exposure prior to regrowth of the epithelium and in-growth of corneal cells into the implants.
Topics: Collagen Type III; Cornea; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate; Methacrylates; Optical Phenomena; Phosphorylcholine; Prostheses and Implants; Refractometry; Scattering, Small Angle; X-Ray Diffraction
PubMed: 26159106
DOI: 10.1016/j.actbio.2015.07.009 -
FEBS Letters Nov 2014Toll-like receptors (TLRs) take part in both the innate and adaptive immune systems. The role of the transmembrane domain in TLR signaling is still elusive, while its...
Toll-like receptors (TLRs) take part in both the innate and adaptive immune systems. The role of the transmembrane domain in TLR signaling is still elusive, while its importance for the TLR activation was clearly demonstrated. In the present study the ability of the TLR3 transmembrane domain to form dimers and trimers in detergent micelles was shown by solution NMR spectroscopy. Spatial structures and free energy magnitudes were determined for the TLR3 transmembrane domain in dimeric and trimeric states, and two possible surfaces that may be used for the helix-helix interaction by the full-length TLR3 were revealed.
Topics: Amino Acid Sequence; Cell Membrane; Humans; Magnetic Resonance Spectroscopy; Micelles; Models, Molecular; Molecular Sequence Data; Phosphorylcholine; Protein Binding; Protein Multimerization; Protein Stability; Protein Structure, Quaternary; Protein Structure, Tertiary; Thermodynamics; Toll-Like Receptor 3
PubMed: 25217833
DOI: 10.1016/j.febslet.2014.08.031