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.

Synthesis and characterisation of liposomal doxorubicin with loaded gold nanoparticles

Developing nanostructures for cancer treatment is growing significantly. Liposomal doxorubicin is a drug that is used in the clinic and represents a lot of benefits over doxorubicin. The development of multifunctional liposomes with different cancer treatment capability enables broader applications of doxorubicin chemotherapy. Many efforts were carried to prepare more effective liposomal formulation through loading gold nanoparticles (GNPs) in the formulation. Here, GNPs with an average size of 6 nm were loaded in liposomal formulation alongside doxorubicin. The hydrodynamic diameter of final formulation was 177.3 ± 33.9 nm that in comparison with liposomes without GNPs (112.5 ± 10.3 nm), GNPs-loaded liposomes showed the bigger hydrodynamic diameter. GNPs-loaded liposomes are slightly positively charged (4.4 ± 1.1 mV), while liposomes without loading the GNPs were negatively charged (-18.5 ± 1.6 mV). Doxorubicin was loaded in this formulation through active loading technique. Doxorubicin loading efficiency in gold-loaded liposomes is slightly lesser than liposomes without GNPs, but still considerably high in comparison to passive loading techniques.

Promising Antibacterial Effects of Silver Nanoparticle-Loaded Tea Tree Oil Nanoemulsion: a Synergistic Combination Against Resistance Threat

Highly resistant pathogens may be developed in patients with immune disorders after prolonged exposure to antibiotics, a growing threat worldwide. In order to overcome these problems, this study introduces a new class of engineered nanosystems comprising of tea tree oil nanoemulsion (TTO NE) loaded with Ag nanoparticles (NPs). Silver shows a strong toxicity towards a wide range of microorganisms. Also, TTO NE could be employed as a promising and safe antimicrobial agent for local therapies of bacterial infections. The nanosystem was prepared by low-energy method. Mean droplet size of the NE was found to be 17.7 nm. Results of the antibacterial assays showed promising ability of the designed nanosystem for eradication of Gram-positive and Gram-negative bacteria (95%). Also, it was shown that introducing colloidal Ag NPs to the TTO NE exerted a synergistic effect against Escherichia coli (FIC 0.48) while only an additive effect was observed against Staphylococcus aureus (FIC 0.75). The antibacterial effects of TTO NE+Ag NPs together with their compatibility with human cells can present them as a suitable candidate to fight against the antibacterial resistance threat.

Molecular and cellular effects of oncogene cooperation in a genetically accurate AML mouse model

Biallelic CEBPA mutations and FMS-like tyrosine kinase receptor 3 (FLT3) length mutations are frequently identified in human acute myeloid leukemia (AML) with normal cytogenetics. However, the molecular and cellular mechanisms of oncogene cooperation remain unclear because of a lack of disease models. We have generated an AML mouse model using knockin mouse strains to study cooperation of an internal tandem duplication (ITD) mutation in the Flt3 gene with commonly observed CCAAT/enhancer binding protein alpha (C/EBPα) mutations. This study provides evidence that FLT3 ITD cooperates in leukemogenesis by enhancing the generation of leukemia-initiating granulocyte-monocyte progenitors (GMPs) otherwise prevented by a block in differentiation and skewed lineage priming induced by biallelic C/EBPα mutations. These cellular changes are accompanied by an upregulation of hematopoietic stem cell and STAT5 target genes. By gene expression analysis in premalignant populations, we further show a role of FLT3 ITD in activating genes involved in survival/transformation and chemoresistance. Both multipotent progenitors and GMP cells contain the potential to induce AML similar to corresponding cells in human AML samples showing that this model resembles human disease.