Systematic Review of Treatment Failure and Clinical Relapses in Leishmaniasis from a Multifactorial Perspective: Clinical Aspects, Factors Associated with the Parasite and Host

From classical approaches to new developments in genetic engineering of live attenuated vaccine against cutaneous leishmaniasis: potential and immunization

Despite the development of a vaccine against cutaneous leishmaniasis in preclinical and clinical studies, we still do not have a safe and effective vaccine for human use. Given this situation, the search for a new prophylactic alternative to control leishmaniasis should be a global priority. A first-generation vaccine strategy-leishmanization, in which live Leishmania major parasites are inoculated into the skin to protect against reinfection, is taking advantage of this situation. Live attenuated Leishmania vaccine candidates are promising alternatives due to their robust protective immune responses. Importantly, they do not cause disease and could provide long-term protection following challenges with a virulent strain. In addition to physical and chemical methods, genetic tools, including the Cre-loxP system, have enabled the selection of safer null mutant live attenuated Leishmania parasites obtained by gene disruption. This was followed by the discovery and introduction of CRISPR/Cas-based gene editing tools, which can be easily and precisely used to modify genes. Here, we briefly review the immunopathology of L. major parasites and then present the classical methods and their limitations for the production of live attenuated vaccines. We then discuss the potential of current genetic engineering tools to generate live attenuated vaccine strains by targeting key genes involved in L. major pathogenesis and then discuss their discovery and implications for immune responses to control leishmaniasis.

Overview of Research on Leishmaniasis in Africa: Current Status, Diagnosis, Therapeutics, and Recent Advances Using By-Products of the Sargassaceae Family

Leishmaniasis in Africa, which has been designated as a priority neglected tropical disease by various global organizations, exerts its impact on millions of individuals, primarily concentrated within this particular region of the world. As a result of the progressively grave epidemiological data, numerous governmental sectors and civil organizations have concentrated their endeavors on this widespread outbreak with the objective of devising appropriate remedies. This comprehensive examination delves into multiple facets of this parasitic ailment, scrutinizing the associated perils, diagnostic intricacies, and deficiencies within the existing therapeutic protocols. Despite the established efficacy of current treatments, they are not immune to deleterious incidents, particularly concerning toxicity and the emergence of parasitic resistance, thus accentuating the necessity of exploring alternative avenues. Consequently, this research not only encompasses conventional therapeutic approaches, but also extends its scope to encompass complementary and alternative medicinal techniques, thereby striving to identify innovative solutions. A particularly auspicious dimension of this study lies in the exploration of natural substances and by-products derived from some brown algae of the Sargassaceae family. These resources possess the potential to assume a pivotal role in the management of leishmaniasis.

Investigating the Effect of Satureja khuzestanica Essential oil on MDR1 Gene Expression in Leishmania major

BACKGROUND

Cutaneous leishmaniasis is among the neglected diseases in the world. Pentavalent antimonial compounds are considered the first-line treatment for this disease. However, using alternative natural products has received great attention due to the side effects of chemical drugs and drug resistance of the Leishmania parasite. The present study aims to investigate the effect of Satureja khuzestanica essential oil (SKEO) on MDR1 gene expression.

METHODS

In this study, standard strains of Leishmania major promastigotes were exposed to 5, 10, 15, and 20 µg/ml of SKEO. MDR1 gene expression of parasites exposed to essential oil was evaluated using real-time PCR. GAPDH was employed as the housekeeping gene for internal control.

RESULTS

Despite the increase, no statistically significant difference was observed in the relative expression of the MDR1 gene between the control group and the groups containing 5, 10, and 20 µg/ml of SKEO (P > 0.05). The relative expression of the MDR1 gene significantly increased in the group containing 15 μg/ml of essential oil compared to the control one (P < 0.05).

CONCLUSION

This study showed that the use of essential oil of Satureja khuzestanica plant can have an increasing effect on the expression of MDR1 gene of Leishmania promastigotes, which is the best case if Satureja khuzestanica essential oil reduces the expression of MDR1 gene. So it seems that the use of essential oil of Satoria plant is effective in controlling Leishmania parasite, but its concentrations induce drug resistance. As a result, concentrations of essential oil should be used that have a controlling effect on the growth and proliferation of Leishmania parasite and also have the least effect on the induction of MDR1 gene expression.