Peptides+antibiotic Combo more effective treatment option for leishmaniasis

The study consisted in the preparation and biological evaluation of new cell-penetrating peptides (CPPs) which, with an antibiotic conjugation, serve as a vehicle or vector for the drug, enabling it to enter the parasite's cell membrane and be released inside, thus causing its death. The result is greater effectiveness, while at the same time a lower number of oral doses of the drug are needed. In addition, the synthesised CPPs are not toxic for mammal cells, but are for the Leishmania. "Although the idea of using CPPs in the treatment of leishmaniasis is not unknown, the importance of this study lies in its high cell-penetrating capacity and the selectivity (mammal vs parasite cells) of the new synthesised and studied peptides", explains Rosa Maria Ortuño.

In particular, the research has served to study peptides made up of non-protein amino acids with a covalent conjugate of doxorubicin (Dox), a drug which is also used in cancer treatments. While Dox in its free form is not active when incubated with Leishmania because it is not capable of penetrating its interior, the Dox-PPC conjugate has demonstrated to be toxic in very low concentrations. Its cell-penetrating capacity has been rationalised through molecular modelling studies. The results are highly promising, and "a great deal of research is still needed before thinking about new drugs, but we are now a little bit closer of our objective", concludes Ortuño.

https://www.mdpi.com/1422-0067/21/20/7502