Activity of paromomycin in vitro against brazilian clinical isolates of Leishmania spp. and its efficacy in vivo on treatment of experimental tegumentary

Author(s)

Elizabeth Magiolo Coser

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2020-02-04

Examining board members

Adriano Cappellazzo Coelho; Selma Giorgio; Nilmar Silvio Moretti

• Advisor: Adriano Cappellazzo Coelho

Abstract

Leishmaniasis is a parasitic disease caused by flagellated protozoa of the genus Leishmania that affects millions of people worldwide in tropical and subtropical areas. In Brazil, the number of cases of disease has increased in recent years, especially in urban areas. The treatment of leishmaniasis in Brazil is limited to drugs that are administered parenterally, are expensive and cause several side effects. Recently, two drugs were approved as alternatives to the treatment of visceral leishmaniasis in Asia: miltefosine and paromomycin (PAR). Although these drugs have not yet been approved for the treatment of leishmaniasis in Brazil, it is necessary to evaluate the efficacy of these drugs as alternative for the treatment of leishmaniasis in Brazil. In this study, the susceptibility to PAR in vitro of clinical isolates of patients with tegumentary leishmaniasis and reference strains of endemic Leishmania species in Brazil was evaluated, as well as its in vivo efficacy in a murine experimental model for one of the species that causes cutaneous leishmaniasis in Brazil: L. (Leishmania) amazonensis. Typing of 16 clinical isolates by PCR of hsp70 gene followed by digestion with the restriction enzyme HaeIII and DNA sequencing of ITS (internal transcribed spacer) allowed the identification of the species among these isolates: 8 isolates were L. (Viannia) braziliensis, 5 isolates L. (L.) amazonensis, two isolates L. (V.) guyanensis and one isolate L. (V.) shawi. The EC50 values of PAR in promastigotes of clinical isolates and reference strains ranged from 4.95 to 205.03 µM, while the EC50 values in intracellular amastigotes ranged 0.19 to 111.2 µM. In vivo studies were performed using BALB/c mice infected with L. (L.) amazonensis and treated with doses of 75, 150, 300 and 600 mg/kg/day of PAR for 14 days administered intraperitoneally. Animals treated with dosages of 300 and 600 mg/kg/day presented a significant reduction in lesion size. In addition, animals treated with 600 mg/kg/day had a reduction in parasite burden of 90%. A second in vivo trial of animals infected with the reference strain of L. (L.) amazonensis and a clinical isolate of the same species treated with dosages of 150 and 600 mg/kg/day of PAR showed that the clinical isolate, more sensitive to PAR in amastigote form in vitro, showed significantly greater reduction in parasite load when compared to the reference strain, suggesting a possible correlation between drug activity in vitro and in vivo treatment efficacy. The results of this study will contribute to evaluate the potential use of PAR in chemotherapy of cutaneous leishmaniasis in Brazil (AU)

• FAPESP's process: 18/03299-0 - Evaluation of the efficacy of paromomycin in the treatment of experimental cutaneous leishmaniasis
• Grantee: Elizabeth Magiolo Coser
• Support Opportunities: Scholarships in Brazil - Master