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PloS One 2024Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum multi-drug resistance protein 1 (Pfmrp1) gene have previously been reported to confer resistance to...
Increased sensitivity of malaria parasites to common antimalaria drugs after the introduction of artemether-lumefantrine: Implication of policy change and implementation of more effective drugs in fight against malaria.
Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum multi-drug resistance protein 1 (Pfmrp1) gene have previously been reported to confer resistance to Artemisinin-based Combination Therapies (ACTs) in Southeast Asia. A total of 300 samples collected from six sites between 2008 and 2019 under an ongoing malaria drug sensitivity patterns in Kenya study were evaluated for the presence of SNPs at Pfmrp1 gene codons: H191Y, S437A, I876V, and F1390I using the Agena MassARRAY® platform. Each isolate was further tested against artemisinin (ART), lumefantrine (LU), amodiaquine (AQ), mefloquine (MQ), quinine (QN), and chloroquine (CQ) using malaria the SYBR Green I-based method to determine their in vitro drug sensitivity. Of the samples genotyped, polymorphism at Pfmrp1 codon I876V was the most frequent, with 59.3% (163/275) mutants, followed by F1390I, 7.2% (20/278), H191Y, 4.0% (6/151), and S437A, 3.3% (9/274). A significant decrease in median 50% inhibition concentrations (IC50s) and interquartile range (IQR) was noted; AQ from 2.996 ng/ml [IQR = 2.604-4.747, n = 51] in 2008 to 1.495 ng/ml [IQR = 0.7134-3.318, n = 40] (P<0.001) in 2019, QN from 59.64 ng/ml [IQR = 29.88-80.89, n = 51] in 2008 to 18.10 ng/ml [IQR = 11.81-26.92, n = 42] (P<0.001) in 2019, CQ from 35.19 ng/ml [IQR = 16.99-71.20, n = 30] in 2008 to 6.699 ng/ml [IQR = 4.976-9.875, n = 37] (P<0.001) in 2019, and ART from 2.680 ng/ml [IQR = 1.608-4.857, n = 57] in 2008 to 2.105 ng/ml [IQR = 1.266-3.267, n = 47] (P = 0.0012) in 2019, implying increasing parasite sensitivity to the drugs over time. However, no significant variations were observed in LU (P = 0.2692) and MQ (P = 0.0939) respectively, suggesting stable parasite responses over time. There was no statistical significance between the mutation at 876 and parasite sensitivity to selected antimalarials tested, suggesting stable sensitivity for the parasites with 876V mutations. These findings show that Kenyan parasite strains are still sensitive to AQ, QN, CQ, ART, LU, and MQ. Despite the presence of Pfmrp1 mutations in parasites among the population.
Topics: Antimalarials; Humans; Plasmodium falciparum; Artemether, Lumefantrine Drug Combination; Malaria, Falciparum; Polymorphism, Single Nucleotide; Multidrug Resistance-Associated Proteins; Kenya; Mefloquine; Amodiaquine; Drug Resistance; Artemisinins; Chloroquine; Quinine; Male; Female
PubMed: 38900782
DOI: 10.1371/journal.pone.0298585 -
Angewandte Chemie (International Ed. in... Jun 2024The 2,2-difluoroethyl group is an important lipophilic hydrogen bond donor in medicinal chemistry, but its incorporation into small molecules is often challenging....
The 2,2-difluoroethyl group is an important lipophilic hydrogen bond donor in medicinal chemistry, but its incorporation into small molecules is often challenging. Herein, we demonstrate electrophilic 2,2-difluoroethylation of thiol, amine and alcohol nucleophiles with a hypervalent iodine reagent, (2,2-difluoro-ethyl)(aryl)iodonium triflate, via a proposed ligand coupling mechanism. This transformation offers a complementary strategy to existing 2,2-difluoroethylation methods and allows access to a wide range of 2,2-difluoroethylated nucleophiles, including the drugs Captopril, Normorphine and Mefloquine.
PubMed: 38900650
DOI: 10.1002/anie.202410954 -
Physiological Reports Jun 2024We sought to determine the physiological relevance of pannexin/purinergic-dependent signaling in mediating conducted vasodilation elicited by capillary stimulation...
We sought to determine the physiological relevance of pannexin/purinergic-dependent signaling in mediating conducted vasodilation elicited by capillary stimulation through skeletal muscle contraction. Using hamster cremaster muscle and intravital microscopy we stimulated capillaries through local muscle contraction while observing the associated upstream arteriole. Capillaries were stimulated with muscle contraction at low and high contraction (6 and 60CPM) and stimulus frequencies (4 and 40 Hz) in the absence and presence of pannexin blocker mefloquine (MEF; 10 M), purinergic receptor antagonist suramin (SUR 10 M) and gap-junction uncoupler halothane (HALO, 0.07%) applied between the capillary stimulation site and the upstream arteriolar observation site. Conducted vasodilations elicited at 6CPM were inhibited by HALO while vasodilations at 60CPM were inhibited by MEF and SUR. The conducted response elicited at 4 Hz was inhibited by MEF while the vasodilation at 40 Hz was unaffected by any blocker. Therefore, upstream vasodilations resulting from capillary stimulation via muscle contraction are dependent upon a pannexin/purinergic-dependent pathway that appears to be stimulation parameter-dependent. Our data highlight a physiological importance of the pannexin/purinergic pathway in facilitating communication between capillaries and upstream arteriolar microvasculature and, consequently, indicating that this pathway may play a crucial role in regulating blood flow in response to skeletal muscle contraction.
Topics: Animals; Male; Mesocricetus; Connexins; Muscle, Skeletal; Muscle Contraction; Capillaries; Vasodilation; Signal Transduction; Cricetinae; Receptors, Purinergic; Arterioles
PubMed: 38898485
DOI: 10.14814/phy2.16113 -
ACS Medicinal Chemistry Letters Jun 2024and are among the most prevalent causes of life-threatening fungal infections globally. The high mortality associated with these infections despite current antifungal...
and are among the most prevalent causes of life-threatening fungal infections globally. The high mortality associated with these infections despite current antifungal therapy highlights the need for new drugs. In our previous work, we demonstrated that an analogue of the clinically used antimalarial mefloquine, (8-chloro-2-(4-chlorophenyl)quinolin-4-yl)(piperidin-2-yl)methanol (), has both antifungal activity and the ability to penetrate the central nervous system. Herein we describe the synthesis and antifungal assay of all four stereoisomers of . All four stereoisomers retain potent antifungal activity with the enantiomers having MIC values of 1 and 4 μg/mL against and respectively, and enantiomers, MIC values of 2 and 8 μg/mL, respectively. These results indicate that the stereochemistry of the piperidine methanol group is not critical for the antifungal properties of and gives guidance to future medicinal chemistry optimization efforts.
PubMed: 38894917
DOI: 10.1021/acsmedchemlett.4c00031 -
Current Microbiology Jun 2024The antimalarial drug Mefloquine has demonstrated antifungal activity against growth and virulence factors of Candida albicans. The current study focused on the...
The antimalarial drug Mefloquine has demonstrated antifungal activity against growth and virulence factors of Candida albicans. The current study focused on the identification of Mefloquine's mode of action in C. albicans by performing cell susceptibility assay, biofilm assay, live and dead assay, propidium iodide uptake assay, ergosterol quantification assay, cell cycle study, and gene expression studies by RT-PCR. Mefloquine inhibited the virulence factors in C. albicans, such as germ tube formation and biofilm formation at 0.125 and 1 mg/ml, respectively. Mefloquine-treated cells showed a decrease in the quantity of ergosterol content of cell membrane in a concentration-dependent manner. Mefloquine (0.25 mg/ml) arrested C. albicans cells at the G2/M phase and S phase of the cell cycle thereby preventing the progression of the normal yeast cell cycle. ROS level was measured to find out oxidative stress in C. albicans in the presence of mefloquine. The study revealed that, mefloquine was found to enhance the ROS level and subsequently oxidative stress. Gene expression studies revealed that mefloquine treatment upregulates the expressions of SOD1, SOD2, and CAT1 genes in C. albicans. In vivo, the antifungal efficacy of mefloquine was confirmed in mice for systemic candidiasis and it was found that there was a decrease in the pathogenesis of C. albicans after the treatment of mefloquine in mice. In conclusion, mefloquine can be used as a repurposed drug as an alternative drug against Candidiasis.
Topics: Antifungal Agents; Candida albicans; Animals; Mefloquine; Mice; Virulence Factors; Candidiasis; Biofilms; Reactive Oxygen Species; Microbial Sensitivity Tests; Oxidative Stress; Cell Cycle; Superoxide Dismutase-1; Ergosterol; Fungal Proteins
PubMed: 38847863
DOI: 10.1007/s00284-024-03739-0 -
The Lancet Regional Health. Western... Jun 2024Cambodia targets malaria elimination by 2023 and all human malaria species by 2025, aligning with WHO's Mekong Malaria Elimination program. The Intermittent Preventive...
BACKGROUND
Cambodia targets malaria elimination by 2023 and all human malaria species by 2025, aligning with WHO's Mekong Malaria Elimination program. The Intermittent Preventive Treatment for Forest Goers (IPTf) project aimed at forest-specific malaria elimination. The study aims to pinpoint the main factors driving malaria transmission in Cambodian forests and evaluate the initial implementation and effectiveness of IPTf in accelerating the elimination of malaria by treating and preventing infections among at-risk populations in these areas.
METHODS
From March 11, 2019, to January 30, 2021, a malaria intervention program took place in isolated forests in Northeast Cambodia. The first phase focused on observing forest goers (FGs) within the forests, documenting their malaria risk. In the second phase, a monthly artesunate-mefloquine IPTf was implemented by trained forest malaria workers who were former FGs conducting interviews, blood collection, and IPTf administration.
FINDINGS
Throughout the two-year period, 2198 FGs were involved in 3579 interviews, with 284 in both the observation and intervention phases. Following IPTf implementation, PCR-confirmed malaria prevalence significantly decreased from 2.9% to 0.5% for and from 21.0% to 4.7% for . Among the 284 participants tracked through both phases, malaria prevalence fell from 2.5% to 0.3% for and from 22.5% to 3.7% for . The intervention phase demonstrated a rapid decline in prevalence among mobile and previously inaccessible populations, while also revealing a higher infection risk associated with activities inaccurately labelled as farming, underscoring the need for customized interventions.
INTERPRETATION
The successful implementation of IPTf in Cambodia's remote forests has markedly decreased malaria prevalence among high-risk groups. Cambodia's National Malaria Program has acknowledged this strategy as essential for malaria elimination intervention, endorsing forest-specific approaches to meet the 2025 goal of eradicating all human malaria species in Cambodia.
FUNDING
The study received funding from the French 5% Initiative (Initiative Canal 2-17SANIN205).
PubMed: 38799614
DOI: 10.1016/j.lanwpc.2024.101093 -
Nutrition and Cancer May 2024Considering the established pharmacokinetics and toxicity profiles, drug repurposing has emerged as an alternative therapeutic approach for treating cancer. Mefloquine...
Considering the established pharmacokinetics and toxicity profiles, drug repurposing has emerged as an alternative therapeutic approach for treating cancer. Mefloquine has previously demonstrated inhibitory effects on multiple cancer types. This study aims to explore the impact of mefloquine on nasopharyngeal carcinoma (NPC). We found that mefloquine, at pharmacologically achievable concentrations, displayed anti-NPC activity while sparing normal counterparts. Mefloquine inhibits proliferation and induces death by reducing the levels of Cyclin A2, Bcl-2, and Bcl-xL. Intriguingly, we observed an increase in the levels of the anti-apoptotic protein Mcl-1. Mefloquine exerts its effects on NPC cells by inducing lysosomal-mediated ROS production, and the heightened expression of Mcl-1 is a consequence of ROS generation in mefloquine-treated NPC cells. The combination of an Mcl-1 inhibitor with mefloquine synergistically inhibits NPC growth in mice without causing substantial toxicity. These findings demonstrate the effectiveness and limited toxicity of mefloquine as a monotherapy and in combination with an Mcl-1 inhibitor. Our research underscores the promise of the mefloquine and Mcl-1 inhibitor combination as a potential treatment for NPC. Additionally, the elevation of Mcl-1 is a compensatory response in cells exposed to oxidative stress, offering a potential target to overcome resistance induced by pro-oxidant therapies.
PubMed: 38795070
DOI: 10.1080/01635581.2024.2358561 -
Current Research in Pharmacology and... 2024infection is a health challenge. Although, antiplasmodial drugs kill the parasites, information on the effects of infection and drugs on the expression of some genes is...
infection is a health challenge. Although, antiplasmodial drugs kill the parasites, information on the effects of infection and drugs on the expression of some genes is limited. Malaria was induced in two different studies using NK65 (chloroquine-susceptible, study 1), and ANKA (chloroquine-resistant, study 2) strains of in 30 male Swiss mice (n = 5) in each study. Mice orally received 10 mL/kg distilled water, (infected control), Mefloquine (MF) (10 mg/kg), MF and Curcumin (CM) (25 mg/kg), MF and CM (50 mg/kg), CM (25 mg/kg) and CM (50 mg/kg). Five mice (un-infected) were used as the control. After treatment, total Ribonucleic acid (RNA) was isolated from liver and erythrocytes while Deoxyribonucleic acid (DNA)-free RNA were converted to cDNA. Polymerase Chain Reaction (PCR) amplification was performed and relative expressions of oxidoreductase, and cytochrome oxidase expressions were determined. Markers of glycolysis, toxicity and antioxidants were determined using ELISA assays. While the expression of was blunted by MF in the susceptible study, co-treatment with curcumin (25 mg/kg) yielded the same results in the chloroquine-resistant study. Similar results were obtained on in both studies. Curcumin decreased in both studies. infection decreased oxidoreductase and cytochrome oxidase but mefloquine-curcumin restored the expression of these genes. While glycolysis and toxicity were inhibited, antioxidant systems improved in the treated groups. Curcumin is needed for effective therapeutic efficacy and prevention of toxicity. infection and treatment modulate the expressions of some genes in the host. Curcumin combination with mefloquine modulates the expression of some genes in the host.
PubMed: 38725654
DOI: 10.1016/j.crphar.2024.100180 -
Malaria Journal May 2024Drug repurposing offers a strategic alternative to the development of novel compounds, leveraging the known safety and pharmacokinetic profiles of medications, such as... (Review)
Review
BACKGROUND
Drug repurposing offers a strategic alternative to the development of novel compounds, leveraging the known safety and pharmacokinetic profiles of medications, such as linezolid and levofloxacin for tuberculosis (TB). Anti-malarial drugs, including quinolones and artemisinins, are already applied to other diseases and infections and could be promising for TB treatment.
METHODS
This review included studies on the activity of anti-malarial drugs, specifically quinolones and artemisinins, against Mycobacterium tuberculosis complex (MTC), summarizing results from in vitro, in vivo (animal models) studies, and clinical trials. Studies on drugs not primarily developed for TB (doxycycline, sulfonamides) and any novel developed compounds were excluded. Analysis focused on in vitro activity (minimal inhibitory concentrations), synergistic effects, pre-clinical activity, and clinical trials.
RESULTS
Nineteen studies, including one ongoing Phase 1 clinical trial, were analysed: primarily investigating quinolones like mefloquine and chloroquine, and, to a lesser extent, artemisinins. In vitro findings revealed high MIC values for anti-malarials versus standard TB drugs, suggesting a limited activity. Synergistic effects with anti-TB drugs were modest, with some synergy observed in combinations with isoniazid or pyrazinamide. In vivo animal studies showed limited activity of anti-malarials against MTC, except for one study of the combination of chloroquine with isoniazid.
CONCLUSIONS
The repurposing of anti-malarials for TB treatment is limited by high MIC values, poor synergy, and minimal in vivo effects. Concerns about potential toxicity at effective dosages and the risk of antimicrobial resistance, especially where TB and malaria overlap, further question their repurposing. These findings suggest that focusing on novel compounds might be both more beneficial and rewarding.
Topics: Drug Repositioning; Tuberculosis; Antimalarials; Antitubercular Agents; Mycobacterium tuberculosis; Humans; Animals
PubMed: 38702649
DOI: 10.1186/s12936-024-04967-2 -
BMJ Case Reports Apr 2024A middle-aged man with progressive multifocal leukoencephalopathy (PML) in a human T-cell lymphotropic virus type-1 (HTLV-1) carrier on haemodialysis presented with mild...
A middle-aged man with progressive multifocal leukoencephalopathy (PML) in a human T-cell lymphotropic virus type-1 (HTLV-1) carrier on haemodialysis presented with mild dysarthria and ataxia. Brain MRI revealed asymmetric T-hyperintense lesions in the cerebral white matter, cerebellum and brainstem. A small amount of JC virus (JCV) genome in cerebrospinal fluid was detected by PCR and cerebellar biopsy demonstrated JCV-DNA presence. Pathological findings showed demyelinating lesions and glial cells with mildly enlarged nuclei, accompanied by T-lymphocytes, neutrophils and plasma cell infiltration. The CD4+/CD8+ratio was 0.83. High-dose corticosteroid therapy was effective for inflammatory PML lesions, and the administration of mefloquine combined with mirtazapine led to favourable outcome. The encephalitis in this case is considered to have occurred secondarily to JCV infection in the presence of HTLV-1 infection. Therefore, it is crucial to investigate the presence of HTLV-1 in order to understand the aetiology of this brain inflammation.
Topics: Humans; Leukoencephalopathy, Progressive Multifocal; Male; HTLV-I Infections; Middle Aged; Human T-lymphotropic virus 1; JC Virus; Coinfection; Mirtazapine; Magnetic Resonance Imaging; Mefloquine
PubMed: 38688573
DOI: 10.1136/bcr-2023-257805