RESUMO
Chlamydia trachomatis (Ct) is the most common cause for bacterial sexually transmitted infections (STIs) worldwide with a tremendous impact on public health. With the aim to unravel novel targets of the chlamydia life cycle, we screen a compound library and identify 28 agents to significantly reduce Ct growth. The known anti-infective agent pentamidine-one of the top candidates of the screen-shows anti-chlamydia activity in low concentrations by changing the metabolism of host cells impairing chlamydia growth. Furthermore, it effectively decreases the Ct burden upon local or systemic application in mice. Pentamidine also inhibits the growth of Neisseria gonorrhea (Ng), which is a common co-infection of Ct. The conducted compound screen is powerful in exploring antimicrobial compounds against Ct in a medium-throughput format. Following thorough in vitro and in vivo assessments, pentamidine emerges as a promising agent for topical prophylaxis or treatment against Ct and possibly other bacterial STIs.
Assuntos
Infecções por Chlamydia , Chlamydia trachomatis , Modelos Animais de Doenças , Pentamidina , Animais , Chlamydia trachomatis/efeitos dos fármacos , Infecções por Chlamydia/tratamento farmacológico , Infecções por Chlamydia/microbiologia , Infecções por Chlamydia/prevenção & controle , Pentamidina/farmacologia , Camundongos , Humanos , Antibacterianos/farmacologia , Feminino , Avaliação Pré-Clínica de Medicamentos , Gonorreia/tratamento farmacológico , Gonorreia/microbiologia , Neisseria gonorrhoeae/efeitos dos fármacos , Células HeLaRESUMO
Pneumocystis jirovecii pneumonia (PJP) in hematopoietic cell transplant (HCT) recipients can be prevented by efficient prophylaxis. We surveyed HCT centers in North America to assess their PJP prophylaxis practices. Most institutions used intravenous (IV) pentamidine (29.6%) or inhaled pentamidine (14.8%); 37% institutions changed from trimethoprim/sulfamethoxazole (TMP-SMX) to another medication after conditioning; and 44% administered no PJP prophylaxis during the pre-engraftment period. Most institutions avoided using TMP-SMX during the pre-engraftment period, mainly because of concerns about myelotoxicity, despite this being the preferred PJP prophylaxis agent. There is a need to evaluate the effects of TMP-SMX on engraftment.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Pneumocystis carinii , Pneumonia por Pneumocystis , Humanos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Pneumonia por Pneumocystis/prevenção & controle , Criança , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Combinação Trimetoprima e Sulfametoxazol/administração & dosagem , Pentamidina/uso terapêutico , Pentamidina/administração & dosagem , Masculino , Antibioticoprofilaxia/métodos , Feminino , Condicionamento Pré-Transplante/métodosRESUMO
Biodegradable nanocarriers possess enormous potential for use as drug delivery systems that can accomplish controlled and targeted drug release, and a wide range of nanosystems have been reported for the treatment and/or diagnosis of various diseases and disorders. Of the various nanocarriers currently available, liposomes and polymer nanoparticles have been extensively studied and some formulations have already reached the market. However, a combination of properties to create a single hybrid system can give these carriers significant advantages, such as improvement in encapsulation efficacy, higher stability, and active targeting towards specific cells or tissues, over lipid or polymer-based platforms. To this aim, this work presents the formulation of poly(lactic-co-glycolic) acid (PLGA) nanoparticles in the presence of a hyaluronic acid (HA)-phospholipid conjugate (HA-DPPE), which was used to anchor HA onto the nanoparticle surface and therefore create an actively targeted hybrid nanosystem. Furthermore, ionic interactions have been proposed for drug encapsulation, leading us to select the free base form of pentamidine (PTM-B) as the model drug. We herein report the preparation of hybrid nanocarriers that were loaded via ion-pairing between the negatively charged PLGA and HA and the positively charged PTM-B, demonstrating an improved loading capacity compared to PLGA-based nanoparticles. The nanocarriers displayed a size of below 150 nm, a negative zeta potential of -35 mV, a core-shell internal arrangement and high encapsulation efficiency (90%). Finally, the ability to be taken up and exert preferential and receptor-mediated cytotoxicity on cancer cells that overexpress the HA specific receptor (CD44) has been evaluated. Competition assays supported the hypothesis that PLGA/HA-DPPE nanoparticles deliver their cargo within cells in a CD44-dependent manner.
Assuntos
Receptores de Hialuronatos , Ácido Hialurônico , Nanopartículas , Pentamidina , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Humanos , Ácido Hialurônico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Receptores de Hialuronatos/metabolismo , Nanopartículas/química , Nanopartículas/administração & dosagem , Pentamidina/química , Pentamidina/administração & dosagem , Portadores de Fármacos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Liberação Controlada de Fármacos , Lipídeos/química , Sistemas de Liberação de MedicamentosRESUMO
Pentamidine and melarsoprol are primary drugs used to treat the lethal human sleeping sickness caused by the parasite Trypanosoma brucei. Cross-resistance to these two drugs has recently been linked to aquaglyceroporin 2 of the trypanosome (TbAQP2). TbAQP2 is the first member of the aquaporin family described as capable of drug transport; however, the underlying mechanism remains unclear. Here, we present cryo-electron microscopy structures of TbAQP2 bound to pentamidine or melarsoprol. Our structural studies, together with the molecular dynamic simulations, reveal the mechanisms shaping substrate specificity and drug permeation. Multiple amino acids in TbAQP2, near the extracellular entrance and inside the pore, create an expanded conducting tunnel, sterically and energetically allowing the permeation of pentamidine and melarsoprol. Our study elucidates the mechanism of drug transport by TbAQP2, providing valuable insights to inform the design of drugs against trypanosomiasis.
Assuntos
Aquagliceroporinas , Microscopia Crioeletrônica , Melarsoprol , Simulação de Dinâmica Molecular , Pentamidina , Trypanosoma brucei brucei , Trypanosoma brucei brucei/metabolismo , Aquagliceroporinas/metabolismo , Aquagliceroporinas/química , Melarsoprol/metabolismo , Melarsoprol/química , Pentamidina/química , Pentamidina/metabolismo , Transporte Biológico , Tripanossomicidas/química , Tripanossomicidas/metabolismo , Tripanossomicidas/farmacologia , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/química , HumanosRESUMO
Receipt of nebulised pentamidine in people with HIV was audited to identify if individuals were appropriately receiving nebulised pentamidine, and whether national guidelines were being followed when prophylaxis was commenced and discontinued. Of 76 people with who received nebulised pentamidine, the main indication for starting nebulised pentamidine was a co-trimoxazole adverse drug reaction. Co-trimoxazole desensitization was not attempted before starting nebulised pentamidine. The main indication for stopping nebulised pentamidine prophylaxis was when immune reconstitution occurred. This single centre audit revealed that national guidelines were being followed in most cases. The lack of information regarding the reason for starting or stopping nebulised pentamidine prophylaxis, or detail of the clinician's concerns about potential poor adherence with oral regimens of prophylaxis as a reason for choosing nebulised pentamidine prophylaxis, identifies a need for improved documentation of clinicians' decision-making. Introduction of pharmacist-led interventions/alerts using patients' electronic records, similar to those used in primary care, would enable the specialist pharmacy team to identify when and if co-trimoxazole desensitization has been offered and discussed/declined before a clinician prescribes nebulised pentamidine as well as enabling identification of those in who pentamidine prophylaxis has been continued, despite "immune reconstitution".
Assuntos
Infecções Oportunistas Relacionadas com a AIDS , Infecções por HIV , Nebulizadores e Vaporizadores , Pentamidina , Pneumonia por Pneumocystis , Combinação Trimetoprima e Sulfametoxazol , Humanos , Pentamidina/administração & dosagem , Pentamidina/uso terapêutico , Pneumonia por Pneumocystis/prevenção & controle , Masculino , Adulto , Feminino , Infecções por HIV/tratamento farmacológico , Combinação Trimetoprima e Sulfametoxazol/administração & dosagem , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Pessoa de Meia-Idade , Londres , Infecções Oportunistas Relacionadas com a AIDS/prevenção & controle , Pneumocystis carinii , Administração por Inalação , Antifúngicos/administração & dosagem , Antifúngicos/uso terapêuticoRESUMO
BACKGROUND: Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection among people living with HIV (PWH), particularly among new and untreated cases. Several regimens are available for the prophylaxis of PCP, including trimethoprim-sulfamethoxazole (TMP-SMX), dapsone-based regimens (DBRs), aerosolized pentamidine (AP), and atovaquone. OBJECTIVES: To compare the efficacy and safety of PCP prophylaxis regimens in PWH by network meta-analysis. METHODS: DATA SOURCES: Embase, MEDLINE, and CENTRAL from inception to June 21, 2023. STUDY ELIGIBILITY CRITERIA: Comparative randomized controlled trials (RCTs). PARTICIPANTS: PWH. INTERVENTIONS: Regimens for PCP prophylaxis either compared head-to-head or versus no treatment/placebo. ASSESSMENT OF RISK OF BIAS: Cochrane risk-of-bias tool for RCTs 2. METHODS OF DATA SYNTHESIS: Title or abstract and full-text screening and data extraction were performed in duplicate by two independent reviewers. Data on PCP incidence, all-cause mortality, and discontinuation due to toxicity were pooled and ranked by network meta-analysis. Subgroup analyses of primary versus secondary prophylaxis, by year, and by dosage were performed. RESULTS: A total of 26 RCTs, comprising 55 treatment arms involving 7516 PWH were included. For the prevention of PCP, TMP-SMX was ranked the most favourable agent and was superior to DBRs (risk ratio [RR] = 0.54; 95% CI, 0.36-0.83) and AP (RR = 0.53; 95% CI, 0.36-0.77). TMP-SMX was also the only agent with a mortality benefit compared with no treatment/placebo (RR = 0.79; 95% CI, 0.64-0.98). However, TMP-SMX was also ranked as the most toxic agent with a greater risk of discontinuation than DBRs (RR = 1.25; 95% CI, 1.01-1.54) and AP (7.20; 95% CI, 5.37-9.66). No significant differences in PCP prevention or mortality were detected among the other regimens. The findings remained consistent within subgroups. CONCLUSIONS: TMP-SMX is the most effective agent for PCP prophylaxis in PWH and the only agent to confer a mortality benefit; consequently, it should continue to be recommended as the first-line agent. Further studies are necessary to determine the optimal dosing of TMP-SMX to maximize efficacy and minimize toxicity.
Assuntos
Infecções por HIV , Metanálise em Rede , Pneumocystis carinii , Pneumonia por Pneumocystis , Ensaios Clínicos Controlados Aleatórios como Assunto , Combinação Trimetoprima e Sulfametoxazol , Humanos , Pneumonia por Pneumocystis/prevenção & controle , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Combinação Trimetoprima e Sulfametoxazol/administração & dosagem , Combinação Trimetoprima e Sulfametoxazol/efeitos adversos , Pneumocystis carinii/efeitos dos fármacos , Infecções por HIV/complicações , Infecções Oportunistas Relacionadas com a AIDS/prevenção & controle , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Dapsona/uso terapêutico , Dapsona/efeitos adversos , Dapsona/administração & dosagem , Pentamidina/uso terapêutico , Pentamidina/administração & dosagem , Pentamidina/efeitos adversos , Atovaquona/uso terapêutico , Atovaquona/efeitos adversos , Antifúngicos/uso terapêutico , Antifúngicos/administração & dosagem , Antifúngicos/efeitos adversos , Resultado do TratamentoRESUMO
OBJECTIVES: In hematology, prophylaxis for Pneumocystis jirovecii pneumonia (PCP) is recommended for patients undergoing hematopoietic stem cell transplantation and in selected categories of intensive chemotherapy for hematologic malignancies. Trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended first-line agent; however, its use is not straightforward. Inhaled pentamidine is the recommended second-line agent; however, aerosolized medications were discouraged during respiratory virus outbreaks, especially during the COVID-19 pandemic, in view of potential contamination risks. Intravenous (IV) pentamidine is a potential alternative agent. We evaluated the effectiveness and tolerability of IV pentamidine use for PCP prophylaxis in adult allogeneic hematopoietic stem cell transplantation recipients and patients with hematologic malignancies during COVID-19. RESULTS: A total of 202 unique patients who received 239 courses of IV pentamidine, with a median of three doses received (1-29). The largest group of the patients (49.5%) who received IV pentamidine were undergoing or had received a hematopoietic stem cell transplant. The most common reason for not using TMP-SMX prophylaxis was cytopenia (34.7%). We have no patients who had breakthrough PCP infection while on IV pentamidine. None of the patients developed an infusion reaction or experienced adverse effects from IV pentamidine. CONCLUSIONS: Pentamidine administered IV monthly is safe and effective.
Assuntos
Administração Intravenosa , COVID-19 , Neoplasias Hematológicas , Transplante de Células-Tronco Hematopoéticas , Pentamidina , Pneumocystis carinii , Pneumonia por Pneumocystis , Humanos , Pentamidina/administração & dosagem , Pentamidina/uso terapêutico , Pentamidina/efeitos adversos , Pneumonia por Pneumocystis/prevenção & controle , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/terapia , Masculino , Estudos Retrospectivos , Pessoa de Meia-Idade , Feminino , Adulto , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Idoso , COVID-19/prevenção & controle , Adulto Jovem , SARS-CoV-2 , Antifúngicos/administração & dosagem , Antifúngicos/uso terapêutico , Antifúngicos/efeitos adversos , Combinação Trimetoprima e Sulfametoxazol/administração & dosagem , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Combinação Trimetoprima e Sulfametoxazol/efeitos adversosRESUMO
Drug binding and interactions with plasma proteins play a crucial role in determining the efficacy of drug delivery, thus significantly impacting the overall pharmacological effect. AGP, the second most abundant plasma protein in blood circulation, has the unique capability to bind drugs and transport various compounds. In our present study, for the first time, we investigated whether AGP, a major component of the acute phase lipocalin in human plasma, can bind with pentamidine derivatives known for their high activity against the fungal pathogen Pneumocystis carinii. This investigation was conducted using integrated spectroscopic techniques and computer-based approaches. According to the results, it was concluded that compounds having heteroatoms (-NCH3) in the aliphatic linker and the addition of a Br atom and a methoxy substituent at the C-2 and C-6 positions on the benzene ring, exhibit strong interactions with the AGP binding site. These compounds are identified as potential candidates for recognition by this protein. MD studies indicated that the tested analogues complexed with AGPs reach an equilibrium state after 60 ns, suggesting the stability of the complexes. This observation was further corroborated by experimental results. Therefore, exploring the interaction mechanism of pentamidine derivatives with plasma proteins holds promise for the development of bis-benzamidine-designed pharmaceutically important drugs.
Assuntos
Orosomucoide , Pentamidina , Ligação Proteica , Humanos , Pentamidina/química , Pentamidina/farmacologia , Pentamidina/metabolismo , Orosomucoide/metabolismo , Orosomucoide/química , Sítios de Ligação , Simulação de Dinâmica Molecular , Simulação de Acoplamento MolecularRESUMO
This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical features, diagnosis, medical and surgical therapy, as well as outcomes of Acanthamoeba keratitis (AK). AK is a significant cause of ocular morbidity, and early diagnosis with timely institution of appropriate therapy is the key to obtaining good outcomes. The varied presentations result in frequent misdiagnosis, and co-infections can increase the morbidity of the disease. The first line of therapy continues to be biguanides and diamidines, with surgery as a last resort.
Assuntos
Ceratite por Acanthamoeba , Humanos , Ceratite por Acanthamoeba/diagnóstico , Ceratite por Acanthamoeba/terapia , Pentamidina/uso terapêutico , Biguanidas/uso terapêuticoRESUMO
PURPOSE: Diffuse gliomas are managed with radiation and temozolomide; however, this therapy often results in hematologic toxicities. Patients undergoing chemoradiation also risk contracting Pneumocystis jirovecii pneumonia (PJP), and frequently receive prophylaxis against PJP during treatment. Independent of chemoradiation, some PJP prophylaxis drugs have the potential to cause myelosuppression, which could require cessation of chemotherapy. Here, we evaluate differences in the frequency of hematologic toxicities during chemoradiation when patients receive PJP prophylaxis. METHODS: This retrospective chart review evaluated patients with primary brain tumors treated with radiation and concurrent temozolomide. Analyses were performed to assess the effect of the type of PJP prophylaxis on risk for neutropenia, lymphopenia, or thrombocytopenia and the severity of these adverse effects as defined using the Common Terminology Criteria for Adverse Events. RESULTS: Of the 217 patients included in this analysis, 144 received trimethoprim-sulfamethoxazole (TMP/SMX) and 69 received pentamidine. Of the patients who received TMP/SMX, 15.3% developed an absolute neutrophil count < 1500 cells/µL compared with 7.2% of patients receiving pentamidine (p = 0.10). Platelet count < 100,000/µL occurred in 18.1% of patients who received TMP/SMX and 20.3% of patients who received pentamidine (p = 0.70). No significant differences in lymphocyte counts between therapies were seen. Severity of hematologic toxicities were similar between PJP prophylaxis groups. CONCLUSION: These findings suggest that the type of PJP prophylaxis does not significantly affect the risk for hematologic toxicity in brain tumor patients receiving radiation and temozolomide. Additional studies are merited to evaluate the higher rate of neutropenia in patients on TMP/SMX observed in this study.
Assuntos
Neoplasias Encefálicas , Neutropenia , Pneumocystis carinii , Pneumonia por Pneumocystis , Humanos , Pneumonia por Pneumocystis/etiologia , Pneumonia por Pneumocystis/prevenção & controle , Combinação Trimetoprima e Sulfametoxazol/efeitos adversos , Pentamidina/farmacologia , Pentamidina/uso terapêutico , Estudos Retrospectivos , Temozolomida/efeitos adversos , Neutropenia/induzido quimicamente , Neutropenia/prevenção & controle , Neoplasias Encefálicas/radioterapiaRESUMO
Psychedelic substances induce profound alterations in consciousness. Careful preparation is therefore essential to limit adverse reactions, enhance therapeutic benefits, and maintain user safety. This paper describes the development of a self-directed, digital intervention for psychedelic preparation. Drawing on elements from the UK Medical Research Council (MRC) framework for developing complex interventions, the design was informed by a four-factor model of psychedelic preparedness, using a person-centred approach. Our mixed-methods investigation consisted of two studies. The first involved interviews with 19 participants who had previously attended a 'high-dose' psilocybin retreat, systematically exploring their preparation behaviours and perspectives on the proposed intervention. The second study engaged 28 attendees of an ongoing psilocybin retreat in co-design workshops, refining the intervention protocol using insights from the initial interviews. The outcome is a co-produced 21-day digital course (Digital Intervention for Psychedelic Preparation (DIPP)), that is organised into four modules: Knowledge-Expectation, Psychophysical-Readiness, Safety-Planning, and Intention-Preparation. Fundamental components of the course include daily meditation practice, supplementary exercises tied to the weekly modules, and mood tracking. DIPP provides a comprehensive and scalable solution to enhance psychedelic preparedness, aligning with the broader shift towards digital mental health interventions.
Assuntos
Alucinógenos , Pentamidina/análogos & derivados , Humanos , Alucinógenos/farmacologia , Psilocibina/farmacologia , Saúde Mental , Estado de ConsciênciaRESUMO
OBJECTIVE: To determine whether a combination of a single intramuscular (IM) dose of pentamidine (7 mg/kg) followed by oral tamoxifen 40 mg/day for 20 days is non-inferior to three IM doses of pentamidine 7 mg/kg in the treatment of cutaneous leishmaniasis with a margin of 15%. METHODS: Phase II, randomised, controlled, open-label, non-inferiority clinical trial. Primary outcome was the complete healing of the lesions 6 months after starting treatment. Secondary outcomes were healing 3 months after starting treatment and determining the presence and severity of adverse effects (AE). RESULTS: The research was concluded with 49 patients; Leishmania (Viannia) guyanensis was the most frequent species isolated. In the primary outcome, 18 (72%) (95% CI: 52.4%-85.7%) of the 25 patients allocated to the intervention group and 24 (100%) (95% CI: 86.2%-100%) of the control group (p = 0.015) met the established criteria of cure. There was no AE with tamoxifen. CONCLUSION: Although a 72% cure rate presented by the combination of tamoxifen and pentamidine was lower than in the control group that achieved a 100% cure, it is still a safe and is a clinically relevant result. It indicates that the therapeutic scheme evaluated may be a promising option for populations in remote areas, however it should be further studied, in order to include a larger number of patients.
Assuntos
Antiprotozoários , Leishmania guyanensis , Leishmaniose Cutânea , Humanos , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Cutânea/patologia , Pentamidina/uso terapêutico , Tamoxifeno/uso terapêuticoRESUMO
N-methyl-D-aspartate (NMDA) receptors are inhibited by many amidine and guanidine compounds. In this work, we studied the mechanisms of their inhibition by sepimostat-an amidine-containing serine protease inhibitor with neuroprotective properties. Sepimostat inhibited native NMDA receptors in rat hippocampal CA1 pyramidal neurons with IC50 of 3.5 ± 0.3 µM at -80 mV holding voltage. It demonstrated complex voltage dependence with voltage-independent and voltage-dependent components, suggesting the presence of shallow and deep binding sites. At -80 mV holding voltage, the voltage-dependent component dominates, and we observed pronounced tail currents and overshoots evidencing a "foot-in-the-door" open channel block. At depolarized voltages, the voltage-independent inhibition by sepimostat was significantly attenuated by the increase of agonist concentration. However, the voltage-independent inhibition was non-competitive. We further compared the mechanisms of the action of sepimostat with those of structurally-related amidine and guanidine compounds-nafamostat, gabexate, furamidine, pentamidine, diminazene, and DAPI-investigated previously. The action of all these compounds can be described by the two-component mechanism. All compounds demonstrated similar affinity to the shallow site, which is responsible for the voltage-independent inhibition, with binding constants in the range of 3-30 µM. In contrast, affinities to the deep site differed dramatically, with nafamostat, furamidine, and pentamidine being much more active.
Assuntos
Pentamidina , Receptores de N-Metil-D-Aspartato , Ratos , Animais , Receptores de N-Metil-D-Aspartato/metabolismo , Pentamidina/metabolismo , Guanidinas/farmacologia , Guanidinas/metabolismo , Hipocampo/metabolismo , Células Cultivadas , N-Metilaspartato/metabolismoRESUMO
Intravenous pentamidine is used for prophylaxis against Pneumocystis jirovecii pneumonia, an infection seen in hematopoietic stem cell transplant recipients. Pentamidine is partially metabolized by CYP2C19, which is vulnerable to pharmacogenetic variation. This retrospective study evaluated allogeneic hematopoietic stem cell transplant patients who received intravenous pentamidine as P. jirovecii pneumonia prophylaxis. The primary objective was the association between CYP2C19 phenotype and discontinuation of pentamidine due to drug-related side effects based on univariate logistic regression (N = 81). Ten patients (12.3%) discontinued pentamidine because of side effects. There was no difference in discontinuation between phenotype groups (p = 0.18) or discontinuation due to side effects (p = 0.76). Overall, no association was seen between phenotypes and pentamidine-related side effects (p = 0.475). Drug discontinuation rates and P. jirovecii pneumonia infection rates were low.
Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Pneumocystis carinii , Pneumonia por Pneumocystis , Humanos , Pentamidina/efeitos adversos , Pneumonia por Pneumocystis/tratamento farmacológico , Pneumonia por Pneumocystis/genética , Antifúngicos/uso terapêutico , Estudos Retrospectivos , Citocromo P-450 CYP2C19/genética , Pneumocystis carinii/genética , FenótipoRESUMO
Organic anion transporting polypeptides OATP1A2, OATP1B1, OATP1B3 and OATP2B1 are Na+ - and ATP-independent exchangers of large, organic compounds, encompassing structurally diverse xenobiotics, including various drugs. These OATPs influence intestinal absorption (OATP2B1), hepatic clearance (OATP1B1/3) and blood to brain penetration (OATP1A2, OATP2B1) of their drug substrates. Consequently, OATP-mediated drug or food interactions may lead to altered pharmacokinetics and toxicity. During drug development, investigation of hepatic OATP1B1 and OATP1B3 is recommended by international regulatory agencies. Most frequently, OATP-drug interactions are investigated in an indirect assay, i.e., by examining uptake inhibition of a radioactive or fluorescent probe. However, indirect assays do not distinguish between transported substrates and non-transported OATP inhibitors. To fill this hiatus, a novel assay, termed competitive counterflow (CCF) has been developed and has since been applied for several OATPs to differentiate between substrates and non-transported inhibitors. However, previous OATP CCF assays, with the exception of that for OATP1B1, used radioactive probes. In the current study, we demonstrate that sulforhodamine 101 or pyranine can be used as fluorescent probes in a CCF assay to identify transported substrates of OATP1A2, or OATPs 1B1, 1B3 and 2B1, respectively. With the help of the newly developed fluorescence-based CCF method, we identify the FDA-approved anti-protozoal drug, pentamidine as a unique substrate of OATP1A2. Furthermore, we confirm the selective, OATP1A2-mediated uptake of pentamidine in a cytotoxicity assay. Based on our results, OATP1A2 may be an important determinant of pentamidine transport through the blood-brain barrier.
Assuntos
Transportadores de Ânions Orgânicos , Transportadores de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Pentamidina , Transportador 1 de Ânion Orgânico Específico do Fígado/metabolismo , Fluorescência , Transporte Biológico , PeptídeosRESUMO
Combining pentamidine with Gram-positive-targeting antibiotics has been proven to be a promising strategy for treating infections from Gram-negative bacteria (GNB). However, which antibiotics pentamidine can and cannot synergize with and the reasons for the differences are unclear. This study aimed to identify the possible mechanisms for the differences in the synergy of pentamidine with rifampicin, linezolid, tetracycline, erythromycin, and vancomycin against GNB. Checkerboard assays were used to detect the synergy of pentamidine and the different antibiotics. To determine the mechanism of pentamidine, fluorescent labeling assays were used to measure membrane permeability, membrane potential, efflux pump activity, and reactive oxygen species (ROS); the LPS neutralization assay was used to evaluate the target site; and quantitative PCR was used to measure changes in efflux pump gene expression. Our results revealed that pentamidine strongly synergized with rifampicin, linezolid, and tetracycline and moderately synergized with erythromycin, but did not synergize with vancomycin against E. coli, K. pneumoniae, E. cloacae, and A. baumannii. Pentamidine increased the outer membrane permeability but did not demolish the outer and inner membranes, which exclusively permits the passage of hydrophobic, small-molecule antibiotics while hindering the entry of hydrophilic, large-molecule vancomycin. It dissipated the membrane proton motive force and inactivated the efflux pump, allowing the intracellular accumulation of antimicrobials that function as substrates of the efflux pump, such as linezolid. These processes resulted in metabolic perturbation and ROS production which ultimately was able to destroy the bacteria. These mechanisms of action of pentamidine on GNB indicate that it is prone to potentiating hydrophobic, small-molecule antibiotics, such as rifampicin, linezolid, and tetracycline, but not hydrophilic, large-molecule antibiotics like vancomycin against GNB. Collectively, our results highlight the importance of the physicochemical properties of antibiotics and the specific mechanisms of action of pentamidine for the synergy of pentamidine-antibiotic combinations. Pentamidine engages in various pathways in its interactions with GNB, but these mechanisms determine its specific synergistic effects with certain antibiotics against GNB. Pentamidine is a promising adjuvant, and we can optimize drug compatibility by considering its functional mechanisms.
Assuntos
Rifampina , Vancomicina , Linezolida/farmacologia , Vancomicina/farmacologia , Rifampina/farmacologia , Pentamidina/farmacologia , Escherichia coli , Espécies Reativas de Oxigênio , Antibacterianos/farmacologia , Bactérias Gram-Negativas , Tetraciclina/farmacologia , EritromicinaRESUMO
Acanthamoeba keratitis (AK) is an eye disease often occurring in contact lens wearers. AK treatment is prolonged and requires multiple drugs, which can lead to adverse effects. Our study aimed to compare the in vitro activities and safety of Miltefosine with that of conventional antimicrobial agents used to treat AK. Acanthamoeba castellanii genotype T4 was obtained from a patient with keratitis and subjected to in vitro susceptibility testing with various antimicrobial agents, including Chlorhexidine (CHX), Pentamidine isethionate (PI)Polyhexamethylene biguanide (PHMB), and Miltefosine to assess their efficacy against Acanthamoeba trophozoites and cyst. The cytotoxicity of the agents was evaluated in Vero cells, and their selectivity indexes (SI) were calculated. Chlorhexidine exhibited the highest amoebicidal activity with the highest selectivity index against the trophozoite and cyst, ranging from 1.17 to 8.35. The selectivity index of PHMB is slightly comparable to Chlorhexidine, exhibiting significant anti-Acanthamoeba activity. On the other hand, Pentamidine isethionate and Miltefosine displayed low SI among the compounds. Pentamidine isethionate was effective at high concentrations, which was toxic. Miltefosine exhibited the lowest cytotoxicity; nevertheless, due to the lowest anti-Acanthamoeba activity presented a low selectivity against the parasite. Further studies on more clinical samples and prolonged incubation time should be done to investigate the effectiveness and toxicity of drugs in both in vitro and in vivo conditions.
Assuntos
Ceratite por Acanthamoeba , Acanthamoeba , Anti-Infecciosos , Cistos , Chlorocebus aethiops , Animais , Humanos , Clorexidina/farmacologia , Trofozoítos , Pentamidina , Células Vero , Ceratite por Acanthamoeba/tratamento farmacológicoRESUMO
Interferon-gamma (IFN-γ) is a type II interferon produced primarily by T cells and natural killer cells. IFN-γ induces the expression of inducible nitric oxide synthase (NOS2) to catalyze Nitric Oxide (NO) production in various immune and non-immune cells. Excessive IFN-γ-activated NO production is implicated in several inflammatory diseases, including peritonitis and inflammatory bowel diseases. In this study, we screened the LOPAC®1280 library in vitro on the H6 mouse hepatoma cell line to identify novel non-steroidal small molecule inhibitors of IFN-γ-induced NO production. Compounds with the highest inhibitory activity were validated, which led to identifying the lead compounds: pentamidine, azithromycin, rolipram, and auranofin. Auranofin was the most potent compound determined based on IC50 and goodness of fit analyses. Mechanistic investigations revealed that majority of the lead compounds suppress the IFN-γ-induced transcription of Nos2 without negatively affecting NO-independent processes, such as the IFN-γ-induced transcription of Irf1, Socs1 and MHC class 1 surface expression. However, all four compounds lower IFN-γ-induced reactive oxygen species amounts. In addition, auranofin significantly reduced IFN-γ-mediated NO and IL6 production in resident as well as thioglycolate-elicited peritoneal macrophages (PMs). Finally, in vivo testing of the lead compounds in the pre-clinical DSS-induced ulcerative colitis mice model revealed pentamidine and auranofin to be the most potent and protective lead compounds. Also, pentamidine and auranofin greatly increase the survival of mice in another inflammatory model: Salmonella Typhimurium-induced sepsis. Overall, this study identifies novel anti-inflammatory compounds targeting IFN-γ-induced NO-dependent processes to alleviate two distinct inflammatory models of disease.
Assuntos
Colite , Sepse , Camundongos , Animais , Interferon gama/metabolismo , Óxido Nítrico/metabolismo , Salmonella typhimurium/fisiologia , Auranofina/farmacologia , Auranofina/uso terapêutico , Pentamidina , Ensaios de Triagem em Larga Escala , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Colite/induzido quimicamente , Colite/tratamento farmacológicoRESUMO
The reaction of alumylene [(Dippnacnac)Al] (1) with C60 fashions the first example of a structurally characterised aluminium-fulleride complex, [{(Dippnacnac)Al}3C60] (2), in which the Al centres are covalently bound to significantly elongated 6 : 6 bonds. Hydrolysis of 2 yields C60H6 and the reaction of 2 with [{Mesnacnac)Mg}2] cleaved off the Al fragments by affording the fulleride [{Mesnacnac)Mg}6C60].
Assuntos
Alumínio , Pentamidina , HidróliseRESUMO
Immunotherapy has emerged as an effective therapeutic approach to several cancer types. The reinvigoration of tumor-infiltrating lymphocyte-mediated immune responses via the blockade of immune checkpoint markers, such as program cell death-1 (PD-1) or its cognate ligand PD-L1, has been the basis for developing clinically effective anticancer therapies. We identified pentamidine, an FDA-approved antimicrobial agent, as a small-molecule antagonist of PD-L1. Pentamidine enhanced T-cell-mediated cytotoxicity against various cancer cells in vitro by increasing the secretion of IFN-γ, TNF-α, perforin, and granzyme B in the culture medium. Pentamidine promoted T-cell activation by blocking the PD-1/PD-L1 interaction. In vivo administration of pentamidine attenuated the tumor growth and prolonged the survival of tumor-bearing mice in PD-L1 humanized murine tumor cell allograft models. Histological analysis of tumor tissues showed an increased number of tumor-infiltrating lymphocytes in tissues derived from pentamidine-treated mice. In summary, our study suggests that pentamidine holds the potential to be repurposed as a novel PD-L1 antagonist that may overcome the limitations of monoclonal antibody therapy and can emerge as a small molecule cancer immunotherapy.