Pentamidine Research Articles

In vitro and in silico antileishmania activity of voriconazole (Vfend)

American Cutaneous Leishmaniasis (ACL) is a public health problem in 88 countries. The treatment of ATL is based on pentavalent antimony, which has several adverse effects. And through new alternatives for the treatment of leishmaniasis, the use of off-label medications appears. The objective of this work was to evaluate, through in vitro and in silico tests, the activity of voriconazole in tablet form as off-label against the promastigote forms of Leishmania amazonensis and Leishmania guyanensis. In the bioassay, species of Leishmania (L.) amazonensis and Leishmania (V.) guyanensis were used, cultivated in RPMI medium with 10% SFBi. The 50% inhibitory concentration (IC50) of voriconazole was evaluated by the inhibition of promastigotes exposed to voriconazole at concentrations of 6.25 to 200 µg.mL-1 diluted in culture medium and fluconazole at 25 to 400 µg.mL-1. In the experiment, parasites plus culture medium and pentamidine isethionate at 3 µg.mL-1 were used as controls for 24, 48 and 72 h in triplicate. The concentrations of voriconazole used in the test showed antileishmanial activity against promastigotes of both Leishmania species, with an IC50 of 5.34 µg.mL-1 for L. amazonensis and 5.66 µg.mL-1 for L. guyanensis. Therefore, the study showed that off-label voriconazole presented better results than fluconazole against Leishmania species, in addition to showing better enzymatic coupling of new targets.

Selection of lansoprazole from an FDA-approved drug library to inhibit the Alzheimer's disease seed-dependent formation of tau aggregates.

The efficacy of current treatments is still insufficient for Alzheimer's disease (AD), the most common cause of Dementia. Out of the two pathological hallmarks of AD amyloid-β plaques and neurofibrillary tangles, comprising of tau protein, tau pathology strongly correlates with the symptoms of AD. Previously, screening for inhibitors of tau aggregation that target recombinant tau aggregates have been attempted. Since a recent cryo-EM analysis revealed distinct differences in the folding patterns of heparin-induced recombinant tau filaments and AD tau filaments, this study focused on AD seed-dependent tau aggregation in drug repositioning for AD. We screened 763 compounds from an FDA-approved drug library using an AD seed-induced tau aggregation in SH-SY5Y cell-based assay. In the first screening, 180 compounds were selected, 72 of which were excluded based on the results of lactate dehydrogenase assay. In the third screening with evaluations of soluble and insoluble tau, 38 compounds were selected. In the fourth screening with 3 different AD seeds, 4 compounds, lansoprazole, calcipotriene, desogestrel, and pentamidine isethionate, were selected. After AD seed-induced real-time quaking-induced conversion, lansoprazole was selected as the most suitable drug for repositioning. The intranasal administration of lansoprazole for 4 months to AD seed-injected mice improved locomotor activity and reduced both the amount of insoluble tau and the extent of phosphorylated tau-positive areas. Alanine replacement of the predicted binding site to an AD filament indicated the involvement of Q351, H362, and K369 in lansoprazole and C-shaped tau filaments. These results suggest the potential of lansoprazole as a candidate for drug repositioning to an inhibitor of tau aggregate formation in AD.

Comparing cytotoxicity and efficacy of miltefosine and standard antimicrobial agents against Acanthamoeba trophozoites and cyst forms: An in vitro study

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.

88-OR: Targeted Drug Delivery to Human ß-Cells Using Novel Nanocapsule Delivery Vehicle for T1D Treatment

In type 1 diabetes (T1D), autoreactive immune cells destroy insulin secreting β-cells in pancreatic islets. Islet transplantation shows promise in restoring glucose homeostasis without exogenous insulin; however, long-term graft survival remains a critical barrier to the success of this treatment. Therapies aimed to protect or proliferate endogenous β-cells have off target affects and require targeted delivery to improve efficacy. We have developed a nanocapsule (NC) delivery system to specifically target and deliver cargo to human β-cells. We hypothesize NCs will selectively be taken up by human β-cells and deliver therapeutic cargo. NCs were synthesized with a water in oil emulsion evaporation technique. NCs were coated via ionic interactions with ectonucleoside triphosphate diphosphohydrolase 3 (ENTPD3) antibody, a human β-cell specific marker or Exendin-4 conjugated to hyaluronic acid (HA-Ex4). NC size, size distribution, charge, stability, and drug release profiles were determined. NCs loaded with pentamidine (PTM) or Cy5 were cultured for 24-168h with human iPSC-derived β-cells (sBC) or injected into the tail vein of NOD-SCID mice. Confocal microscopy confirmed delivery of cargo to β-cells and pancreatic islets, viability, and cytotoxicity. NCs were 271 ± 7nm in size with excellent size homogeneity (polydispersity index 0.06 ± 0.03, n=3). NCs displayed a sustained release of cargo for >45 days (n=5). In vitro, we observed no cytotoxicity of NCs up to 168h (n=3) and a significant increase in β-cell death with PTM loaded ENTPD3 coated NCs compared to controls at 24 (p<0.001, n=4) and 72h (p<0.01, n=4). sBCs treated with PTM loaded ENTPD3 coated NCs had more insulin+ dead cells (88 ± 4%) than controls (p<0.01, n=4). ENTPD3 or HA-Ex4 NCs were internalized into sBCs in vitro and pancreatic islets in vivo respectively. Our data shows long term stability and in vivo targeting of NCs to β-cells and supports use of our NCs for targeted delivery of therapeutics to human β-cells to treat T1D. Disclosure J.Collins: None. K.Holcomb: None. A.Ocampo: None. A.Shilleh: None. H.A.Russ: Advisory Panel; Sigilon Therapeutics, Inc., Consultant; Prellis, Minutia, Eli Lilly and Company. N.L.Farnsworth: None. Funding JDRF (1-INO-2022-1231-S-B); National Institutes of Health (P30-DK116073)

Co-delivery of amphotericin B and pentamidine loaded niosomal gel for the treatment of Cutaneous leishmaniasis

Topical drug delivery is preferable route over systemic delivery in case of Cutaneous leishmaniasis (CL). Among the available agents, amphotericin B (AmB) and pentamidine (PTM) showed promising result against CL. However, monotherapy is associated with incidences of reoccurrence and resistance. Combination therapy is therefore recommended. Thin film hydration method was employed for amphotericin B-pentamidine loaded niosomes (AmB-PTM-NIO) preparation followed by their incorporation into chitosan gel. The optimization of AmB-PTM-NIO was done via Box Behnken Design method and in vitro and ex vivo analysis was performed. The optimized formulation indicated 226 nm particle size (PS) with spherical morphology, 0.173 polydispersity index (PDI), −36 mV zeta potential (ZP) and with entrapment efficiency (EE) of 91% (AmB) and 79% (PTM), respectively. The amphotericin B-pentamidine loaded niosomal gel (AmB-PTM-NIO-Gel) showed desirable characteristics including physicochemical properties, pH (5.1 ± 0.15), viscosity (31870 ± 25 cP), and gel spreadability (280 ± 26.46%). In vitro release of the AmB and PTM from AmB-PTM-NIO and AmB-PTM-NIO-Gel showed more prolonged release behavior as compared to their respective drug solution. Higher skin penetration, greater percentage inhibition and lower IC50 against the promastigotes shows that AmB-PTM-NIO has better antileishmanial activity. The obtained findings suggested that the developed AmB-PTM-NIO-Gel has excellent capability of permeation via skin layers, sustained release profile and augmented anti-leishmanial outcome of the incorporated drugs.

Efficacy of pentamidine-loaded chitosan nanoparticles as a novel drug delivery system for Leishmania tropica.

The present study compares the in vitro effects of nanoparticles loaded pentamidine drug and conventional pentamidine on Leishmania tropica. Herein, pentamidine-loaded chitosan nanoparticles (PTN-CNPs) have been synthesized through an ionic gelation method with sodium tripolyphosphate (TPP). Next, the physical characteristics of PTN-CNPs were determined through the surface texture, zeta potential, in vitro drug release, drug loading content (DLC), and encapsulation efficacy (EE) and compared its efficacy with free pentamidine (PTN) drug against promastigotes and axenic amastigotes forms of L. tropica in vitro. The PTN-CNPs displayed a spherical shape having a size of 88 nm, an almost negative surface charge (-3.09 mV), EE for PTN entrapment of 86%, and in vitro drug release of 92% after 36 h. In vitro antileishmanial activity of PTN-CNPs and free PTN was performed against Leishmania tropica KWH23 promastigote and axenic amastigote using 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyletetrazolium bromide (MTT) assay. It was observed that the effect of PTN-CNPs and free PTN on both forms of the parasite was dose and time dependent. Free PTN presented low efficacy even at higher dose (40 µg/ml) with 25.6 ± 1.3 and 26.5 ±1.4 mean viability rate of the promastigotes and axenic amastigotes, respectively after 72 hrs incubation. While PTN-CNPs showed strong antileishmanial effects on both forms of parasite with 16 ± 0.4 and 19 ± 0.7 mean viability rate at the same higher concentration (40 µg/ml) after 72 hrs incubation. Half maximal inhibitory concentration (IC50) values of PTN-CNPs toward promastigotes and amastigotes were obtained as 0.1375 µg/ml and 0.1910 µg/ml, respectively. In conclusion, PTN-CNPs effectively inhibited both forms of the L. tropica; however, its effect was more salient on promastigotes. This data indicates that the PTN-CNPs act as a target drug delivery system. However, further research is needed to support its efficacy in animal and human CL.

Repurposing pentamidine using hyaluronic acid-based nanocarriers for skeletal muscle treatment in myotonic dystrophy

In a context of drug repurposing, pentamidine (PTM), an FDA-approved antiparasitic drug, has been proposed to reverse the splicing defects associated in myotonic dystrophy type 1 (DM1). However, clinical use of PTM is hinder by substantial toxicity, leading to find alternative delivery strategies. In this work we proposed hyaluronic acid-based nanoparticles as a novel encapsulation strategy to efficiently deliver PTM to skeletal muscles cells. In vitro studies on C2C12 myoblasts and myotubes showed an efficient nanoparticles' internalization with minimal toxicity. More interestingly, our findings evidenced for the first time the endosomal escape of hyaluronic acid-based nanocarriers. Ex vivo studies showed an efficient nanoparticles' internalization within skeletal muscle fibers. Finally, the therapeutic efficacy of PTM-loaded nanosystems to reduce the number of nuclear foci has been demonstrated in a novel DM1 in vitro model. So far, current data demonstrated the potency of hyaluronic acid-based nanosystems as efficient nanocarrier for delivering PTM into skeletal muscle and mitigate DM1 pathology.

Selective delivery of pentamidine toward cancer cells by self-assembled nanoparticles

Pentamidine (PTM) is an aromatic diamidine approved for the treatment of parasitic infections that has been recently proposed for possible repositioning as an anticancer drug. To this aim, efforts have been made to improve its therapeutic efficacy and reduce associated adverse effects through both covalent derivatization and association with nanocarriers. To efficiently encapsulate PTM into biocompatible nanoparticles and to enhance its selectivity toward cancer cells, a squalene (SQ) derivative (1,1′,2-tris-norsqualenoic acid, SQ-COOH) was selected to prepare PTM-loaded nanocarriers. Indeed, SQ and its derivatives self-assemble into nanoparticles in aqueous media. Furthermore, SQ-bioconjugates strongly interact with low-density lipoproteins (LDL), thus favoring preferential accumulation in cells overexpressing the LDL receptor (LDLR). We report here the preparation of nanocarriers by ion-pairing between the negatively charged SQ-COOH and the positively charged PTM free base (PTM-B), which allowed the covalent grafting of SQ to PTM to be avoided. The nanoparticles were characterized (mean size < 200 nm and zeta potential < -20 mV for SQ-COOH/PTM-B 3:1 molar ratio) and molecular modelling studies of the SQ-COOH/PTM-B interaction confirmed the nanocarrier stability. Finally, the ability to indirectly target LDLR-overexpressing cancer cells was evaluated by in vitro cell viability assays and confirmed by LDLR silencing, serum privation and simvastatin treatment.

A reactive oxygen species Ca2+ signalling pathway identified from a chemical screen for modifiers of sugar-activated circadian gene expression.

Sugars are essential metabolites for energy and anabolism that can also act as signals to regulate plant physiology and development. Experimental tools to disrupt major sugar signalling pathways are limited. We performed a chemical screen for modifiers of activation of circadian gene expression by sugars to discover pharmacological tools to investigate and manipulate plant sugar signalling. Using a library of commercially available bioactive compounds, we identified 75 confident hits that modified the response of a circadian luciferase reporter to sucrose in dark-adapted Arabidopsis thaliana seedlings. We validated the transcriptional effect on a subset of the hits and measured their effects on a range of sugar-dependent phenotypes for 13 of these chemicals. Chemicals were identified that appear to influence known and unknown sugar signalling pathways. Pentamidine isethionate was identified as a modifier of a sugar-activated Ca2+ signal that acts as a calmodulin inhibitor downstream of superoxide in a metabolic signalling pathway affecting circadian rhythms, primary metabolism and plant growth. Our data provide a resource of new experimental tools to manipulate plant sugar signalling and identify novel components of these pathways.

Identification of four compounds from the Pharmakon library with antifungal activity against Candida auris and species of Cryptococcus.

Fungal infections can be lethal and the options to fight them are scarce. We tested 1600 molecules for their ability to control the growth of two important fungal pathogens, namely Candida auris and species of Cryptococcus. Four of these compounds showed promising antifungal activities.

Discriminator for Cutaneous Leishmaniasis Using MALDI-MSI in a Murine Model.

Cutaneous leishmaniasis is a skin disease caused by flagellate protozoa of the genus Leishmania and transmitted by sandflies of the genus Lutzomyia. Around 1 million new cases occur in the world annually, with a total of 12 million people affected, mainly in rural areas with low access to health services and adequate treatments. In the area of the Americas, Colombia has one of the highest infection rates after Brazil. Topical treatments with pentamidine isethionate (PMD) present an attractive alternative due to their ease of application and low costs. However, cutaneous leishmaniasis lesions present nodules with seropurulent exudate that, when drying, form hyperkeratotic lesions, hindering the effective penetration of drugs for their treatment. The use of molecular histology techniques, such as MALDI-MSI, allow in situ evaluation of the penetration of the treatment to the sections of the dermis where the disease-causing parasite resides. However, the large volume of information generated makes it impossible to process it manually. Machine learning techniques allow the unsupervised processing of large amounts of information, generating prediction models for the classification of new information. This work proposes a low-cost method to generate cutaneous leishmaniasis detection and classification models using MALDI-MSI images taken from murine models. The proposed models allow a 95% efficiency when separating healthy samples from infected samples and an effectiveness of 67% when separating effectively treated samples from unsuccessfully treated samples.

Nanotechnological approaches for pentamidine delivery

Pentamidine (PTM), which is a diamine that is widely known for its antimicrobial activity, is a very interesting drug whose mechanism of action is not fully understood. In recent years, PTM has been proposed as a novel potential drug candidate for the treatment of mental illnesses, myotonic dystrophy, diabetes, and tumors. Nevertheless, the systemic administration of PTM causes severe side effects, especially nephrotoxicity. In order to efficiently deliver PTM and reduce its side effects, several nanosystems that take advantage of the chemical characteristics of PTM, such as the presence of two positively charged amidine groups at physiological pH, have been proposed as useful delivery tools. Polymeric, lipidic, inorganic, and other types of nanocarriers have been reported in the literature for PTM delivery, and they are all in different development phases. The available approaches for the design of PTM nanoparticulate delivery systems are reported in this review, with a particular emphasis on formulation strategies and in vitro/in vivo applications. Furthermore, a critical view of the future developments of nanomedicine for PTM applications, based on recent repurposing studies, is provided.Graphical abstractCreated with BioRender.com

Impact of Genetic Diversity and Genome Plasticity of Leishmania spp. in Treatment and the Search for Novel Chemotherapeutic Targets.

Leishmaniasis is one of the major public health concerns in Latin America, Africa, Asia, and Europe. The absence of vaccines for human use and the lack of effective vector control programs make chemotherapy the main strategy to control all forms of the disease. However, the high toxicity of available drugs, limited choice of therapeutic agents, and occurrence of drug-resistant parasite strains are the main challenges related to chemotherapy. Currently, only a small number of drugs are available for leishmaniasis treatment, including pentavalent antimonials (SbV), amphotericin B and its formulations, miltefosine, paromomycin sulphate, and pentamidine isethionate. In addition to drug toxicity, therapeutic failure of leishmaniasis is a serious concern. The occurrence of drug-resistant parasites is one of the causes of therapeutic failure and is closely related to the diversity of parasites in this genus. Owing to the enormous plasticity of the genome, resistance can occur by altering different metabolic pathways, demonstrating that resistance mechanisms are multifactorial and extremely complex. Genetic variability and genome plasticity cause not only the available drugs to have limitations, but also make the search for new drugs challenging. Here, we examined the biological characteristics of parasites that hinder drug discovery.

A Review on Cutaneous Leishmaniasis

Leishmaniasis is a vector-borne disease caused by flagellated protozoans belonging to the genus Leishmania. Cutaneous leishmaniasis (CL) is a parasitic disease transmitted by sandflies called phlebotomine that causes a variety of skin lesions. It has a wide range of clinical manifestations that are influenced by a number of unknown parasite and host factors. The disease can take many forms, ranging from self-limited and even self-healing cutaneous manifestations to fatal systemic disease. The standard treatment is pentavalent antimony. Pentavalent antimonials are the cornerstones of cutaneous leishmaniasis treatment, with novel oral and topical options on the horizon. Many lesions heal on their own and does not need to be treated. Antimonials are likely to cause a high number of reversible side effects. Other medications used in treatment include amphotericin B, pentamidine isethionate, paromomycin and antifungals. Although the cutaneous version of the disease is frequently self-limiting, it can leave considerable scarring and lead to more invasive mucocutaneous disease. As a result, treatment to prevent these problems may be considered. In endemic regions, leishmania parasites are frequently diagnosed clinically and, if possible, by microscopic inspection of lesion biopsy samples to visually confirm the aetiology. In non-endemic nations, the use of more advanced medical procedures that allow for species identification is mainly limited to research or therapeutic contexts. The application, use and adverse effects of drugs for systemic and topical treatment are also described.

Evaluation of in vitro activity of five antimicrobial agents on Acanthamoeba isolates and their toxicity on human corneal epithelium.

Acanthamoeba keratitis (AK) is an important cause of ocular morbidity in both contact lens wearers and non wearers. Medical management comprises prolonged empiric treatment with multiple drugs, leading to adverse effects and suboptimal cure. The present study evaluated the efficiency and safety of common antimicrobial agents used in treatment of AK. Six Acanthamoeba isolates (four AK, two water samples) were axenized and subjected to in vitro susceptibility testing against chlorhexidine, pentamidine isethionate, polymyxin B, miltefosine, and fluconazole to check for trophocidal and cysticidal activity. The safety profile was analysed by observing the cytotoxicity of the highest cidal concentration toward human corneal epithelial cell (HCEC) line. Chlorhexidine had the lowest cidal concentration against both cysts and trophozoites (range 4.16-25 μg/ml) followed by pentamidine isethionate (range 25-166.7 μg/ml). Both agents were nontoxic to HCEC. Polymyxin B (range 25-200 μg/ml) and fluconazole (range 64-512 μg/ml) had relatively higher minimum inhibitory concentrations (MIC); fluconazole was nontoxic even at 1024 μg/ml, but cytotoxicity was observed at 400 μg/ml with polymyxin B. Miltefosine was not effective against cysts at tested concentrations. A. castellanii were more susceptible to all agents (except pentamidine isethionate) than A. lenticulata. Clinical isolates were less susceptible to polymyxin B and fluconazole than environmental isolates, reverse was true for miltefosine. Chlorhexidine and pentamidine isethionate were the most effective and safe agents against both trophozoites and cysts forms of our Acanthamoeba isolates. Fluconazole had higher MIC but was nontoxic. Polymyxin B was effective at high MIC but therapeutic dose was found toxic. Miltefosine, at tested concentrations, could not inhibit cysts of Acanthamoeba. Clinical isolates had higher MICs for polymyxin B and fluconazole.

Efficacy and safety of pentamidine isethionate for tegumentary and visceral human leishmaniasis: a systematic review.

We performed a systematic review of the literature to investigate the efficacy and safety of pentamidine isethionate for the treatment of human tegumentary and visceral leishmaniasis. A total of 616 papers were evaluated, and 88 studies reporting data on 3108 cases of leishmaniasis (2082 patients with tegumentary leishmaniasis and 1026 with visceral leishmaniasis) were finally included. The majority of available studies were on New World cutaneous leishmaniasis and visceral leishmaniasis caused by Leishmania donovani. At the same time, few data are available for Old World cutaneous leishmaniasis, mucosal leishmaniasis, and visceral leishmaniasis caused by L. infantum. Pooled cure rate for tegumentary leishmaniasis was 78.8% (CI 95%, 76.9-80.6%) and 92.7% (CI 95%, 88.3-97.1%) according to controlled randomized trial and observational studies and case report and case series respectively. Pooled cure rate for visceral leishmaniasis was 84.8% (CI 95%, 82.6-87.1%) and 90.7% (CI 95%, 84.1-97.3%) according to controlled randomized trial and observational studies and case report and case series, respectively. Comparable cure rate was observed in recurrent and refractory cases of visceral leishmaniasis. Concerning the safety profile, among about 2000 treated subjects with some available information, the most relevant side effects were six cases of arrhythmia (including four cases of fatal ventricular fibrillation), 20 cases of irreversible diabetes, 26 cases of muscular aseptic abscess following intramuscular administration. Pentamidine isethionate is associated with a similar cure rate of the first-line anti-leishmanial drugs. Severe and irreversible adverse effect appear to be rare. The drug may still have a role in the treatment of any form of human leishmaniasis when the first-line option has failed or in patients who cannot tolerate other drugs also in the setting of travel medicine. In difficult cases, the drug can also be considered as a component of a combination treatment regimen.

In Vitro Activity of Pentamidine Isethionate against Trophozoite and Cyst of Acanthamoeba

Background:Acanthamoebae are a causative agent of Acanthamoeba keratitis (AK) in immunocompetent individuals. Since access to propamidine isethionate (Brolene®) as a first-line treatment has been limited in recent years, in the current study, we examined the effects of pentamidine isethionate against trophozoite and cyst forms of Acanthamoeba.Methods:This experimental study was conducted in the Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran, during 2019–2020. Pentamidine isethionate at concentrations of 50, 100, 200, 400, 600, 800, and 1000 μM were tested against trophozoites and cyst stages of T4 genotype, at 24- and 48-hour incubation period, and the viability was determined by trypan blue staining. In addition, the cytotoxic effect of the drug was examined in Vero cells using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.Results:The 50% inhibitory concentration (IC50) of pentamidine isethionate on trophozoite after 24 and 48h were 97.4 μM and 60.99 μM. These results on cyst after 24 and 48h were 470 μM and 175.5 μM, respectively. In MTT assay, the drug showed an inhibitory effect on Vero cell growth with IC50 values of 115.4 μM and 87.42 μM after 24h and 48h, respectively.Conclusion:Pentamidine isethionate exhibited an inhibitory effect on trophozoite and cyst. Given that the trophozoicidal activity of the drug is in the safe dose, it could be suggested as an alternative in patients with AK; however, further investigation is needed in an animal model to confirm the data.

Safety and efficacy of reduced-dose pentamidine as second-line treatment for HIV-related pneumocystis pneumonia

ObjectivesParenteral pentamidine isethionate (PM) 4 mg/kg/day is recommended as an alternative therapeutic regimen after failure of first-line treatment for pneumocystis pneumonia (PCP). However, the dose is often reduced to 3 mg/kg/day in clinical settings because of high rates of adverse events and drug toxicity. Although considered equally efficacious, this lower dose has not been well evaluated. MethodsThis was a single-center, retrospective cohort study that analyzed 75 patients with HIV-PCP who were treated with trimethoprim-sulfamethoxazole, but discontinued treatment because of treatment failure or adverse events; they were then administered 3 mg/kg/day of intravenous PM as a salvage therapy. The primary outcomes were the regimen completion rate with the reduced PM dose. Results and conclusionsIn total, 40 (53.3%) of the eligible patients completed PCP therapy with reduced-dose PM salvage treatment. The overall survival rate of PCP was 73 (97.3%). The median duration of second-line PM treatment was 8.0 days (interquartile range: 6.0–10.0). Although, the adverse events with reduced-dose PM were observed in 41 (54.7%), including 35 treatment-limiting adverse events, grade 3 or 4 adverse events occurred in only three patients (thrombocytopenia, one patient; neutropenia, two patients). Life-threating adverse events, such as hypoglycemia and arrhythmia, were not observed with reduced-dose PM. Salvage therapy with reduced-dose PM for patients with HIV-PCP is relatively safe and effective; moreover, life-threating adverse events did not occur. This therapy could be recommended for patients with HIV-PCP who fail to respond to first-line treatment with trimethoprim-sulfamethoxazole.

Drug screening of food and drug administration-approved compounds against Babesia bovis in vitro

Babesia (B.) bovis is one of the main etiological agents of bovine babesiosis, causes serious economic losses to the cattle industry. Control of bovine babesiosis has been hindered by the limited treatment selection for B. bovis, thus, new options are urgently needed. We explored the drug library and unbiasedly screened 640 food and drug administration (FDA) approved drug compounds for their inhibitory activities against B. bovis in vitro. The initial screening identified 13 potentially effective compounds. Four potent compounds, namely mycophenolic acid (MPA), pentamidine (PTD), doxorubicin hydrochloride (DBH) and vorinostat (SAHA) exhibited the lowest IC50 and then selected for further evaluation of their in vitro efficacies using viability, combination inhibitory and cytotoxicity assays. The half-maximal inhibitory concentration (IC50) values of MPA, PTD, DBH, SAHA were 11.38 ± 1.66, 13.12 ± 4.29, 1.79 ± 0.15 and 45.18 ± 7.37 μM, respectively. Of note, DBH exhibited IC50 lower than that calculated for the commonly used antibabesial drug, diminazene aceturate (DA). The viability result revealed the ability of MPA, PTD, DBH, SAHA to prevent the regrowth of treated parasite at 4 × and 2 × of IC50. Antagonistic interactions against B. bovis were observed after treatment with either MPA, PTD, DBH or SAHA in combination with DA. Our findings indicate the richness of FDA approved compounds by novel potent antibabesial candidates and the identified potent compounds especially DBH might be used for the treatment of animal babesiosis caused by B. bovis.

Pentamidine-Loaded Lipid and Polymer Nanocarriers as Tunable Anticancer Drug Delivery Systems

Initially developed as a synthetic analogue of insulin, pentamidine (PTM) is an antimicrobial drug that has recently shown in vitro and in vivo anticancer activity. Nevertheless, systemic administration of PTM causes severe side effects, especially nephrotoxicity. Here we propose the association of PTM to different biocompatible nanosystems in order to compare the physicochemical characteristics of the loaded nanocarriers and their influence on the drug cytotoxicity toward cancer cells. In particular, PTM (as free base or with different counterions) was encapsulated into liposomes and poly(lactide-co-glycolide) (PLGA) nanoparticles and all the formulations have been deeply characterized concerning mean diameter, polydispersity index, zeta potential, stability, morphology, PTM loading, and drug release profile. The anticancer activity was evaluated on a human ovarian cancer cell line over 72 h. Results showed that PTM is efficiently loaded into liposomes with a transmembrane citrate or sulfate gradient; concerning PLGA nanoparticles, important association occurred, thanks to ionic interactions between the drug and the polymer. The in vitro studies confirmed the anticancer activity of PTM, which was gradually released with different profiles depending on the drug form and the nanocarrier structure.