Federica Bruno

In vitro antileishmanial activity of trans-stilbene and terphenyl compounds

Leishmaniasis are globally widespread parasitic diseases which often leads to death if left untreated. Currently available drugs present different drawbacks, so there is an urgent need to develop new, safe and cost-effective drugs against leishmaniasis. In this study we tested a small library of trans-stilbene and terphenyl derivatives against promastigote, amastigotes and intramacrophage amastigote forms of Leishmania infantum. Two compounds of the series, the trans-stilbene 3 and the terphenyl 11, presented the best activity and safety profiles. Terphenyl 11 showed a leshmanicidal activity higher than pentostam and the ability to induce apoptosis selectively in Leishmania infantum while saving macrophages and primary epithelial cells. Our data indicate that terphenyl compounds, as well as stilbenes, are endowed with leishmanicidal activity, showing potential for further studies in the context of leishmanial therapy.

“Click” on PLGA-PEG and hyaluronic acid: Gaining access to anti-leishmanial pentamidine bioconjugates: Click conjugation of Pentamidine to PLGA-PEG and hyaluronic acid

Pentamidine (Pent), an antiparasitic drug used for the treatment of visceral leishmaniasis, has been modified with terminal azide groups and conjugated to two different polymer backbones (PLGA-PEG [PP] copolymer and hyaluronic acid [HA]) armed with alkyne end-groups. The conjugation has been performed by Copper Catalyzed Azido Alkyne Cycloaddition (CuAAC) using CuSO4 /sodium ascorbate as metal source. The novel PP-Pent and HA-Pent bioconjugates are proposed, respectively, as non-targeted and targeted drug delivery systems against Leishmania infections. Moreover, Pent has been encapsulated into PP nanoparticles by the oil-in-water emulsion method, with the aim to compare the biological activity of the bioconjugates with that of the classical drug-loaded delivery system that physically entraps the therapeutic agent. Biological assays against Leishmania infantum amastigote-infected macrophages and primary macrophages revealed that Pent, either covalently conjugated with polymers or loaded into polymeric nanoparticles, turned out to be more potent and less toxic than the free Pent.

Cytotoxic Screening and In Vitro Evaluation of Pentadecane Against Leishmania infantum Promastigotes and Amastigotes

Abstract:  Pentadecane is an organic compound that is made up of primarily carbon and hydrogen atoms. Pentadecane is a floral volatile found in many different plants and essential oils and also in crude extracts of some plants, and it shows antimicrobial activity. This study investigated in vitro effects of pentadecane in Leishmania infantum parasites and found that it decreases growth by 86 ± 2% both in promastigotes (half maximal inhibitory concentration [IC50] = 65.3 μM) and in amastigotes (IC50 = 60.5 μM), resulting in a reduction of macrophage infection; growth inhibition was 77% at 300 μM. Analysis of propidium iodide incorporation in L. infantum, treated with pentadecane at 48 hr, suggested that cells were arresting in the sub-G0/G1 and G1 phases of the cell cycle, whereas cytotoxicity assay of pentadecane in immortalized cells lines DH82 and U937 and in primary epithelial cells of Cercopiteco showed that it caused negligible cytotoxic effect. This study shows that pentadecane has antimicrobial activity against L. infantum parasites in in vitro culture.

Effectiveness of red alga Asparagopsis taxiformis extracts against Leishmania infantum

Abstract Leishmaniasis is a disease with a worldwide distribution affecting both humans and animals. There is a need to identify and develop new drugs for the treatment of leishmaniasis. This study showed that crude ethanolic extracts of the red alga Asparagopsis taxiformis have a powerful effect against L. infantum, the prevalent species of the genus Leishmania in the Mediterranean basin. L. infantum demonstrated decreased vitality with increasing concentration of the algal extracts. At a concentration of 40 μg/mL, the extracts achieved 100% mortality of the parasite and the LD50 value was 25 μg/mL for promastigotes and 9 μg/mL for amastigotes. Algal extracts caused morphological alterations and apoptosis in Leishmania cells. The potential cytotoxic action of crude extracts was investigated by a MTT viability assay on DH82 and Vero cell lines but there was no cytotoxic effect. The potential of red alga A. taxiformis metabolites as anti-leishmanial agents merits further pharmacological investigation.

Suspected cutaneous leishmaniasis in a sample of Westerns Sicily residents: what correlation with occupation?

BACKGROUND Leishmaniasis is a widespread infectious disease, but there is not much information about its prevalence in high risk occupational categories. OBJECTIVES The aim of this study is to assess the prevalence of Leishmania immunological positivity in human skin tissues collected from subjects living in Western Sicily, with suspected cutaneous Leishmania infection, in order to explore the risk possibly related to occupation. METHODS 318 consecutive subjects (M/F ratio=1.0, mean age=40±25.4 years), attending the Dermatology Department of the University of Palermo Hospital from 2013 to 2015, without any previous history of Leishmania infection and performing various occupations, were included. Parasite isolation and PCR-RT test on skin scrapings were performed to evaluate the immunological status; all data were analyzed by the chi square test, comparing all positive results from the different provinces. RESULTS 81 (50.9%) out of 159 females and 79 (49.7%) out of 159 males were found PCR-RT positive to Leishmania infantum, with a higher risk in the Agrigento district (p<0.001) and in subjects living in rural areas (p=0.0038), regardless of the type of work performed. The observed animal leishmaniasis prevalence in the same areas shows the endemic status of the disease in Sicily. CONCLUSIONS Although based on a relatively small sample, our study shows that cutaneous leishmaniasis represents a health care problem with a medical and social impact in Western Sicily. An active surveillance system and the establishment of diagnosis and treatment centres could be useful in controlling this public health problem.

Effects of trans-stilbene and terphenyl compounds on different strains of Leishmania and on cytokines production from infected macrophages

Most of the antileishmanial modern therapies are not satisfactory due to high toxicity or emergence of resistance and high cost of treatment. Previously, we observed that two compounds of a small library of trans-stilbene and terphenyl derivatives, ST18 and TR4, presented the best activity and safety profiles against Leishmania infantum promastigotes and amastigotes. In the present study we evaluated the effects of ST18 and the TR4 in 6 different species of Leishmania and the modifications induced by these two compounds in the production of 8 different cytokines from infected macrophages. We observed that TR4 was potently active in all Leishmania species tested in the study showing a leishmanicidal activity higher than that of ST18 and meglumine antimoniate in the most of the species. Moreover, TR4 was able to decrease the levels of IL-10, a cytokine able to render the host macrophage inactive allowing the persistence of parasites inside its phagolysosome, and increase the levels of IL-1β, a cytokine important for host resistance to Leishmania infection by inducible iNOS-mediated production of NO, and IL-18, a cytokine implicated in the development of Th1-type immune response.