Use of topical rSm29 in combination with intravenous meglumine antimoniate in the treatment of cutaneous leishmaniasis: A randomized controlled trial.

BACKGROUND: Cutaneous leishmaniasis (CL) caused by Leishmania (Viannia) braziliensis is associated with an inflammatory response. Granzyme (GzmB) and IL-1ß play a key role in the pathology. Meglumine antimoniate (MA) is the first-choice drug for the treatment of CL, but therapy failure is observed in up to 50% of the cases. The protein, rSm29 of Schistosoma mansoni, down-modulates pro-inflammatory cytokine production. We evaluate if the combination of topical rSm29 plus MA increases the cure rate of CL. METHODS: In this randomized clinical trial, 91 CL patients were allocated in 3 groups. All cases received MA (20 mg/kg/weight) for 20 days. Group 1 used topical rSm29 (10 µg), group 2 a placebo topically applied, and group 3 received only MA. RESULTS: The cure rate on day 90 was 71% in subjects treated with rSm29 plus MA, and 43% in patients who received MA plus placebo or MA alone (P < 0.05). There was a decrease in GzmB and an increase in IFN-γ (P < 0.05) in supernatants of skin biopsies of the lesions obtained on D7 of therapy (P < 0.05) in patients who received rSm29. CONCLUSION: rSm29 associated with MA reduces GzmB levels, is more effective than MA alone, and decreases CL healing time. CLINICAL TRIALS REGISTRATION: ClinicalTrial.gov under NCT06000514.

Assessment of nebivolol efficacy in experimental models of toxoplasmosis: insights into parasite burden reduction and neuronal protection.

This study investigates the efficacy of nebivolol (NBV) in experimental models of toxoplasmosis, focusing on parasite burden reduction and neuronal protection. In the acute model of experimental toxoplasmosis, Swiss mice infected with RH strain tachyzoites received oral NBV chlorhydrate doses of 2 mg/kg/day and 4 mg/kg/day for 8 days. Treatment with NBV significantly reduced parasite burden compared to vehicle and standard drug (PYR) groups. In the chronic model of experimental toxoplasmosis, C57/BL6 mice infected with the ME49 strain received NBV chlorhydrate 41 days post-infection and were evaluated after 10 days of treatment. NBV chlorhydrate effectively reduced cyst number and area, as well as bradyzoite burden compared to controls. Histological analysis demonstrated that NBV chlorhydrate preserved neuronal count, with the 4 mg/kg/day dose yielding counts similar to non-infected mice. Statistical analysis confirmed significant differences compared to control groups. Furthermore, immunohistochemical analysis revealed a significant reduction in iNOS labeling in the brains of mice treated with NBV chlorhydrate, indicating a decrease in nitric oxide production compared to control groups. These findings suggest NBV's potential as a promising candidate for toxoplasmosis treatment, highlighting its ability to reduce parasite burden and protect neuronal integrity. Further research is warranted to elucidate NBV's mechanisms of action and its clinical application in managing toxoplasmosis.

Cost-effectiveness study of therapeutic approaches for mucosal leishmaniasis.

This study aimed to estimate the cost-effectiveness of four therapeutic approaches available for mucosal leishmaniasis in Brazil: miltefosine, meglumine antimoniate, combined with and without pentoxifylline, and liposomal amphotericin B. The perspective adopted was that of the Brazilian Unified National Health System (SUS). The outcome of interest was "cured patient", which was analyzed using a decision tree model. Estimates of direct costs and effectiveness were obtained from the scientific literature. Meglumine antimoniate alone was the base comparator strategy; liposomal amphotericin B showed an incremental cost-effectiveness ratio (ICER) of USD 7,409.13 per cured patient, and the combination of meglumine antimoniate with pentoxifylline presented an ICER of USD 85.13. Miltefosine was absolutely dominated, with higher cost and similar effectiveness when compared to meglumine antimoniate. Sensitivity analyses, varying the cost by ±25%, did not change the results. However, when the cost of miltefosine was estimated at less than USD 171.23, this strategy was dominant over meglumine antimoniate alone. The results confirm that treatment with liposomal amphotericin B remains the option with the highest ICER among the approaches analyzed. Miltefosine may be cost-effective based on the variation in the acquisition price, which deserves attention because it is the only available oral option. The non-accounting of other aspects prevent the use of these results immediately to support decision-making, but they point out the need to negotiate the prices of drugs available for mucosal leishmaniasis and indicates the need of encouraging technology transfer or other actions aimed at expanding the performance of the Brazilian national industrial complex.

The Search for Drugs Derived from Natural Products for Toxoplasma gondii Infection Treatment in the Last 20 Years - A Systematic Review.

INTRODUCTION: Toxoplasmosis is a worldwide distributed zoonosis caused by Toxoplasma gondii (T. gondii), an obligate intracellular protozoan. The infection in immunocompetent hosts usually progresses with mild or no symptoms. However, in immunocompromised individuals, this disease can cause severe or fatal symptoms. METHOD: Sulfadiazine and pyrimethamine are two drugs used as standard therapies for human toxoplasmosis. Although they do not cause chronic infection, they may cause hematological toxicity, hypersensitivity, intolerance, teratogenic effects, gastrointestinal disorders, and bone marrow suppression. RESULTS: The limited effect, significant toxicity, and emerging resistance to current drugs available to treat T. gondii infections require investigating other effective, nontoxic, and well-tolerated alternatives. Medicinal plants are, traditionally, the most promising sources used to treat infectious diseases Conclusion: This review provides data on new therapeutic and prophylactic methods for T. gondii infection based on the use of extracts and/or compounds derived from natural products, which have been reported to be useful as alternative treatment options in the last 20 years.

Case Report: Cutaneous Leishmaniasis: A Case Series with Intralesional Treatment in Northeast Brazil.

In 2022, the Pan American Health Organization recommended the intralesional application (IL) of pentavalent antimonials in adult patients with localized cutaneous leishmaniasis (CL) caused by Leishmania (Viannia) braziliensis. Other guidelines differ from that recommendation, considering that infections caused by a Leishmania species that can be associated with increased risk for mucosal leishmaniasis, in particular L. (V.) braziliensis, should not be eligible for intralesional treatment. This was a prospective interventional study carried out with eight patients diagnosed with CL residing in northeast Brazil during the period from 2019 to 2022. To our knowledge, this is the first prospective study on the subject conducted in the northeast region, which has the second-highest number of cases in the country. In our sample, clinical cure was achieved with the use of intralesional treatment in all cases, and there were no serious adverse events or mucosal involvement during the 1-year follow-up period. We emphasize the importance of using the right criteria for choosing this therapeutic modality and highlight the advantages of intralesional treatment due to the lower risk of adverse events and cost reduction to health services.

Innovating Leishmaniasis Treatment: A Critical Chemist's Review of Inorganic Nanomaterials.

Leishmaniasis, a critical Neglected Tropical Disease caused by Leishmania protozoa, represents a significant global health risk, particularly in resource-limited regions. Conventional treatments are effective but suffer from serious limitations, such as toxicity, prolonged treatment courses, and rising drug resistance. Herein, we highlight the potential of inorganic nanomaterials as an innovative approach to enhance Leishmaniasis therapy, aligning with the One Health concept by considering these treatments' environmental, veterinary, and public health impacts. By leveraging the adjustable properties of these nanomaterials─including size, shape, and surface charge, tailored treatments for various diseases can be developed that are less harmful to the environment and nontarget species. We review recent advances in metal-, oxide-, and carbon-based nanomaterials for combating Leishmaniasis, examining their mechanisms of action and their dual use as standalone treatments or drug delivery systems. Our analysis highlights a promising yet underexplored frontier in employing these materials for more holistic and effective disease management.

Photodynamic therapy offers a novel approach to managing miltefosine-resistant cutaneous leishmaniasis.

Cutaneous leishmaniasis (CL) is a neglected disease caused by Leishmania parasites. The oral drug miltefosine is effective, but there is a growing problem of drug resistance, which has led to increasing treatment failure rates and relapse of infections. Photodynamic therapy (PDT) combines a light source and a photoactive drug to promote cell death by oxidative stress. Although PDT is effective against several pathogens, its use against drug-resistant Leishmania parasites remains unexplored. Herein, we investigated the potential of organic light-emitting diodes (OLEDs) as wearable light sources, which would enable at-home use or ambulatory treatment of CL. We also assessed its impact on combating miltefosine resistance in Leishmania amazonensis-induced CL in mice. The in vitro activity of OLEDs combined with 1,9-dimethyl-methylene blue (DMMB) (OLED-PDT) was evaluated against wild-type and miltefosine-resistant L. amazonensis strains in promastigote (EC50 = 0.034 µM for both strains) and amastigote forms (EC50 = 0.052 µM and 0.077 µM, respectively). Cytotoxicity in macrophages and fibroblasts was also evaluated. In vivo, we investigated the potential of OLED-PDT in combination with miltefosine using different protocols. Our results demonstrate that OLED-PDT is effective in killing both strains of L. amazonensis by increasing reactive oxygen species and stimulating nitric oxide production. Moreover, OLED-PDT showed great antileishmanial activity in vivo, allowing the reduction of miltefosine dose by half in infected mice using a light dose of 7.8 J/cm2 and 15 µM DMMB concentration. In conclusion, OLED-PDT emerges as a new avenue for at-home care and allows a combination therapy to overcome drug resistance in cutaneous leishmaniasis.

4-Quinolinylhydrazone analogues kill Leishmania (Leishmania) amazonensis by inducing apoptosis and mitochondria-dependent pathway cell death.

Despite efforts, available alternatives for the treatment of leishmaniasis are still scarce. In this work we tested a class of 15 quinolinylhydrazone analogues and presented data that support the use of the most active compound in cutaneous leishmaniasis caused by Leishmania amazonensis. In general, the compounds showed activity at low concentrations for both parasitic forms (5.33-37.04 µM to promastigotes, and 14.31-61.98 µM to amastigotes). In addition, the best compound (MHZ15) is highly selective for the parasite. Biochemical studies indicate that the treatment of promastigotes with MHZ15 leads the loss of mitochondrial potential and increase in ROS levels as the primary effects, which triggers accumulation of lipid droplets, loss of plasma membrane integrity and apoptosis hallmarks, including DNA fragmentation and phosphatidylserine exposure. These effects were similar in the intracellular form of the parasite. However, in this parasitic form there is no change in plasma membrane integrity in the observed treatment time, which can be attributed to metabolic differences and the resilience of the amastigote. Also, ultrastructural changes such as vacuolization suggesting autophagy were observed. The in vivo effectiveness of MHZ15 in the experimental model of cutaneous leishmaniasis was carried out in mice of the BALB/c strain infected with L. amazonensis. The treatment by intralesional route showed that MHZ15 acted with great efficiency with significantly reduction in the parasite load in the injured paws and draining lymph nodes, without clinical signs of distress or compromise of animal welfare. In vivo toxicity was also evaluated and null alterations in the levels of hepatic enzymes aspartate aminotransferase, and alanine aminotransferase was observed. The data presented herein demonstrates that MHZ15 exhibits a range of favorable characteristics conducive to the development of an antileishmanial agent.

Natural resistance to meglumine antimoniate is associated with treatment failure in cutaneous leishmaniasis caused by Leishmania (Viannia) panamensis.

The multifactorial basis of therapeutic response can obscure the relation between antimicrobial drug susceptibility and clinical outcome. To discern the relationship between parasite susceptibility to meglumine antimoniate (SbV) and therapeutic outcome of cutaneous leishmaniasis, risk factors for treatment failure were considered in evaluating this relationship in ninety-one cutaneous leishmaniasis patients and corresponding clinical strains of Leishmania (Viannia) panamensis. Parasite susceptibility to 32 µg SbV/mL (plasma Cmax) was evaluated in primary human macrophages, PBMCs, and U937 macrophages. Early parasitological response to treatment was determined in lesions of a subgroup of patients, and pathogenicity of Sb-resistant and sensitive clinical strains was compared in BALB/c mice. Parasite survival in cell models and patient lesions was determined by qRT-PCR of Leishmania 7SLRNA transcript. Parasite loads in BALB/c mice were quantified by limiting dilution analysis. The disparate Sb-susceptibility of parasite subpopulations distinguished by isoenzyme profiles (zymodemes) was manifest in all cell models. Notably, Sb-resistance defined by parasite survival, was most effectively discerned in U937 macrophages compared with primary human host cells, significantly higher among strains from patients who failed treatment than cured and, significantly associated with treatment failure. Each unit increase in transformed survival rate corresponded to a 10.6-fold rise in the odds of treatment failure. Furthermore, treatment failure was significantly associated with naturally Sb-resistant zymodeme 2.3 strains, which also produced larger lesions and parasite burdens in BALB/c mice than Sb-sensitive zymodeme 2.2 strains. The confounding effect of host risk factors for treatment failure in discerning this association was evidenced in comparing strains from patients with and without the defined risk factors for treatment failure. These results establish the association of natural resistance to meglumine antimoniate with treatment failure, the importance of host risk factors in evaluating drug susceptibility and treatment outcome, and the clinical and epidemiological relevance of natural Sb-resistance in L. (V.) panamensis subpopulations.

Amphotericin B resistance in Leishmania amazonensis: In vitro and in vivo characterization of a Brazilian clinical isolate.

In Brazil, Leishmania amazonensis is the etiological agent of cutaneous and diffuse cutaneous leishmaniasis. The state of Maranhão in the Northeast of Brazil is prevalent for these clinical forms of the disease and also has high rates of HIV infection. Here, we characterized the drug susceptibility of a L. amazonensis clinical isolate from a 46-year-old man with diffuse cutaneous leishmaniasis coinfected with HIV from this endemic area. This patient underwent several therapeutic regimens with meglumine antimoniate, liposomal amphotericin B, and pentamidine, without success. In vitro susceptibility assays against promastigotes and intracellular amastigotes demonstrated that this isolate had low susceptibility to amphotericin B, when compared with the reference strain of this species that is considered susceptible to antileishmanial drugs. Additionally, we investigated whether the low in vitro susceptibility would affect the in vivo response to amphotericin B treatment. The drug was effective in reducing the lesion size and parasite burden in mice infected with the reference strain, whereas those infected with the clinical isolate and a resistant line (generated experimentally by stepwise selection) were refractory to amphotericin B treatment. To evaluate whether the isolate was intrinsically resistant to amphotericin B in animals, infected mice were treated with other drugs that had not been used in the treatment of the patient (miltefosine, paromomycin, and a combination of both). Our findings demonstrated that all drug schemes were able to reduce lesion size and parasite burden in animals infected with the clinical isolate, confirming the amphotericin B-resistance phenotype. These findings indicate that the treatment failure observed in the patient may be associated with amphotericin B resistance, and demonstrate the potential emergence of amphotericin B-resistant L. amazonensis isolates in an area of Brazil endemic for cutaneous leishmaniasis.

Immunotherapy Combining Mimotopes Selected by Phage Display Plus Amphotericin B Is Effective for Treatment Against Visceral Leishmaniasis.

The treatment for visceral leishmaniasis (VL) causes toxicity in patients, entails high cost and/or leads to the emergence of resistant strains. No human vaccine exists, and diagnosis presents problems related to the sensitivity or specificity of the tests. Here, we tested two phage clones, B1 and D11, which were shown to be protective against Leishmania infantum infection in a murine model as immunotherapeutics to treat mice infected with this parasite species. The phages were used alone or with amphotericin B (AmpB), while other mice received saline, AmpB, a wild-type phage (WTP) or WTP/AmpB. Results showed that the B1/AmpB and D11/AmpB combinations induced polarised Th1-type cellular and humoral responses, which were primed by high levels of parasite-specific IFN-γ, IL-12, TNF-α, nitrite and IgG2a antibodies, which reflected in significant reductions in the parasite load in distinct organs of the animals when analyses were performed 1 and 30 days after the treatments. Reduced organic toxicity was also found in these animals, as compared with the controls. In conclusion, preliminary data suggest the potential of the B1/AmpB and D11/AmpB combinations as immunotherapeutics against L. infantum infection.

Complex cutaneous leishmaniasis in a pediatric patient.

Cutaneous leishmaniasis (CL), a parasitic infection caused by Leishmania protozoa and transmitted by sandfly bites, can be classified into Old World and New World subtypes. We report a case of a 2-year-old female who developed complex CL after travel to Panama. Ultimately, successful treatment required two rounds of liposomal amphotericin B. We report this case for its challenging clinical course and management.

Recurrent acquired ocular toxoplasmosis associated with Kyrieleis plaques and documented allergy to sulfonamide-A treatment proposal for two rare conditions.

The aim of this study was to describe a case of a patient with ocular toxoplasmosis, which has resulted in Kyrieleis plaques formation (segmental periarteritis associated with severe inflammation) and later follow-up and alternative treatment due to documented allergy to sulfonamide. A 33-year-old Brazilian woman diagnosed with acute toxoplasmosis, initially treated with sulfonamide, developed a critical cutaneous rash. Cotrimoxazole was changed to clindamycin and pyrimethamine, and prednisone was started. The medication was maintained for 45 days. Four months later, she developed retinal lesions suggestive of toxoplasmosis with Kyrieleis plaques in the upper temporal vessels. Pyrimethamine, clindamycin, and prednisone were initiated until healing. She presented reactivation months later, and a suppressive treatment with pyrimethamine was instituted for one year. This is the first report to use the combination of clindamycin with pyrimethamine in the treatment and recurrence prophylaxis for OT in a documented allergy to sulfonamide.

Unmasking the Mechanism behind Miltefosine: Revealing the Disruption of Intracellular Ca2+ Homeostasis as a Rational Therapeutic Target in Leishmaniasis and Chagas Disease.

Originally developed as a chemotherapeutic agent, miltefosine (hexadecylphosphocholine) is an inhibitor of phosphatidylcholine synthesis with proven antiparasitic effects. It is the only oral drug approved for the treatment of Leishmaniasis and American Trypanosomiasis (Chagas disease). Although its precise mechanisms are not yet fully understood, miltefosine exhibits broad-spectrum anti-parasitic effects primarily by disrupting the intracellular Ca2+ homeostasis of the parasites while sparing the human hosts. In addition to its inhibitory effects on phosphatidylcholine synthesis and cytochrome c oxidase, miltefosine has been found to affect the unique giant mitochondria and the acidocalcisomes of parasites. Both of these crucial organelles are involved in Ca2+ regulation. Furthermore, miltefosine has the ability to activate a specific parasite Ca2+ channel that responds to sphingosine, which is different to its L-type VGCC human ortholog. Here, we aimed to provide an overview of recent advancements of the anti-parasitic mechanisms of miltefosine. We also explored its multiple molecular targets and investigated how its pleiotropic effects translate into a rational therapeutic approach for patients afflicted by Leishmaniasis and American Trypanosomiasis. Notably, miltefosine's therapeutic effect extends beyond its impact on the parasite to also positively affect the host's immune system. These findings enhance our understanding on its multi-targeted mechanism of action. Overall, this review sheds light on the intricate molecular actions of miltefosine, highlighting its potential as a promising therapeutic option against these debilitating parasitic diseases.

Local amphotericin B therapy for Cutaneous Leishmaniasis: A systematic review.

BACKGROUND: Cutaneous leishmaniasis (CL) is characterized by potentially disfiguring skin ulcers carrying significant social stigma. To mitigate systemic drug exposure and reduce the toxicity from available treatments, studies addressing new local therapeutic strategies using available medications are coming up. This review systematically compiles preclinical and clinical data on the efficacy of amphotericin B (AmB) administered locally for cutaneous leishmaniasis. METHODOLOGY: Structured searches were conducted in major databases. Clinical studies reporting cure rates and preclinical studies presenting any efficacy outcome were included. Exclusion criteria comprised nonoriginal studies, in vitro investigations, studies with fewer than 10 treated patients, and those evaluating AmB in combination with other antileishmanial drug components. PRINCIPAL FINDINGS: A total of 21 studies were identified, encompassing 16 preclinical and five clinical studies. Preclinical assessments generally involved the topical use of commercial AmB formulations, often in conjunction with carriers or controlled release systems. However, the variation in the treatment schedules hindered direct comparisons. In clinical studies, topical AmB achieved a pooled cure rate of 45.6% [CI: 27.5-64.8%; I2 = 79.7; p = 0.002), while intralesional (IL) administration resulted in a 69.8% cure rate [CI: 52.3-82.9%; I2 = 63.9; p = 0.06). In the direct comparison available, no significant difference was noted between AmB-IL and meglumine antimoniate-IL administration (OR:1.7; CI:0.34-9.15, I2 = 79.1; p = 0.00), however a very low certainty of evidence was verified. CONCLUSIONS: Different AmB formulations and administration routes have been explored in preclinical and clinical studies. Developing therapeutic technologies is evident. Current findings might be interpreted as a favorable proof of concept for the local AmB administration which makes this intervention eligible to be explored in future well-designed studies towards less toxic treatments for leishmaniasis.

Compounds with potentialities as novel chemotherapeutic agents in leishmaniasis at preclinical level.

Leishmaniasis are neglected infectious diseases caused by kinetoplastid protozoan parasites from the genus Leishmania. These sicknesses are present mainly in tropical regions and almost 1 million new cases are reported each year. The absence of vaccines, as well as the high cost, toxicity or resistance to the current drugs determines the necessity of new treatments against these pathologies. In this review, several compounds with potentialities as new antileishmanial drugs are presented. The discussion is restricted to the preclinical level and molecules are organized according to their chemical nature, source and molecular targets. In this manner, we present antimicrobial peptides, flavonoids, withanolides, 8-aminoquinolines, compounds from Leish-Box, pyrazolopyrimidines, and inhibitors of tubulin polymerization/depolymerization, topoisomerase IB, proteases, pteridine reductase, N-myristoyltransferase, as well as enzymes involved in polyamine metabolism, response against oxidative stress, signaling pathways, and sterol biosynthesis. This work is a contribution to the general knowledge of these compounds as antileishmanial agents.

Long-Term Low-Dose Pyrimethamine Use for the Prevention of Ocular Toxoplasmosis Recurrences: A Cohort Study.

PURPOSE: To describe the effect of long-term, low-dose pyrimethamine for the prevention of ocular toxoplasmosis (OT) recurrences. METHODS: Sixty-three consecutive patients with inactive ocular toxoplasmosis and positive toxoplasma IgG serology were included. Pyrimethamine (25 mg) + folinic acid (15 mg) were administered every other day (three times weekly) for 12 months. Eighteen patients received the treatment for an additional six months as part of an extension study. RESULTS: Thirty-eight patients (60.3%, n = 63) were female; 38 (60.3%) had a previous history of recurrence and 37 (58.7%) had active OT within the preceding 12 months. Three (4.8%) patients had unilateral recurrences at 8, 12 and 18 months after starting intermittent pyrimethamine treatment. Five patients (7.9%) were discontinued due to hematological, renal and hepatic changes. Treatment was considered successful in 42 patients (84%). CONCLUSION: Long-term, low-dose pyrimethamine can be considered as a treatment option for the prevention of ocular toxoplasmosis recurrence in selected patients, with only a few, mild and reversible systemic adverse events.

Treatment using vanillin-derived synthetic molecules incorporated into polymeric micelles is effective against infection caused by Leishmania amazonensis species.

Treatment against leishmaniasis presents problems, mainly due to the toxicity of the drugs, high cost, and the emergence of resistant strains. A previous study showed that two vanillin-derived synthetic molecules, 3s [4-(2-hydroxy-3-(4-octyl-1H-1,2,3-triazol-1-yl)propoxy)-3-methoxybenzaldehyde] and 3t [4-(3-(4-decyl-1H-1,2,3-triazol-1-yl)-2-hydroxypropoxy)-3-methoxybenzaldehyde], presented antileishmanial activity against Leishmania infantum, L. amazonensis, and L. braziliensis species. In the present work, 3s and 3t were evaluated to treat L. amazonensis-infected mice. Molecules were used pure or incorporated into Poloxamer 407-based micelles. In addition, amphotericin B (AmpB) and its liposomal formulation, Ambisome®, were used as control. Animals received the treatment and, one and 30 days after, they were euthanized to evaluate immunological, parasitological, and biochemical parameters. Results showed that the micellar compositions (3s/Mic and 3t/Mic) induced significant reductions in the lesion mean diameter and parasite load in the infected tissue and distinct organs, as well as a specific and significant antileishmanial Th1-type immune response, which was based on significantly higher levels of IFN-γ, IL-12, nitrite, and IgG2a isotype antibodies. Drug controls showed also antileishmanial action; although 3s/Mic and 3t/Mic have presented better and more significant parasitological and immunological data, which were based on significantly higher IFN-γ production and lower parasite burden in treated animals. In addition, significantly lower levels of urea, creatinine, alanine transaminase, and aspartate transaminase were found in mice treated with 3s/Mic and 3t/Mic, when compared to the others. In conclusion, results suggest that 3s/Mic and 3t/Mic could be considered as therapeutic candidates to treat against L. amazonensis infection.

N6-methyltubercidin gives sterile cure in a cutaneous Leishmania amazonensis mouse model.

Leishmania is a trypanosomatid parasite that causes skin lesions in its cutaneous form. Current therapies rely on old and expensive drugs, against which the parasites have acquired considerable resistance. Trypanosomatids are unable to synthesize purines relying on salvaging from the host, and nucleoside analogues have emerged as attractive antiparasitic drug candidates. 4-Methyl-7-ß-D-ribofuranosyl-7H-pyrrolo[2,3-d]pyrimidine (CL5564), an analogue of tubercidin in which the amine has been replaced by a methyl group, demonstrates activity against Trypanosoma cruzi and Leishmania infantum. Herein, we investigated its in vitro and in vivo activity against L. amazonensis. CL5564 was 6.5-fold (P = 0.0002) more potent than milteforan™ (ML) against intracellular forms in peritoneal mouse macrophages, and highly selective, while combination with ML gave an additive effect. These results stimulated us to study the activity of CL5564 in mouse model of cutaneous Leishmania infection. BALB/c female and male mice infected by L. amazonensis treated with CL5564 (10 mg kg−1, intralesional route for five days) presented a >93% reduction of paw lesion size likely ML given orally at 40 mg kg−1, while the combination (10 + 40 mg kg−1 of CL5564 and ML, respectively) caused >96% reduction. The qPCR confirmed the suppression of parasite load, but only the combination approach reached 66% of parasitological cure. These results support additional studies with nucleoside derivatives.

Casiopeina III-ia: A Copper Compound with Potential Use for Treatment of Infections Caused by Leishmania mexicana.

INTRODUCTION: Casiopeina III-ia (CasIII-ia) is a mixed chelate copper (II) compound capable of interacting with free radicals generated in the respiratory chain through redox reactions, producing toxic reactive oxygen species (ROS) that compromise the viability of cancer cells, bacteria and protozoa. Due to its remarkable effect on protozoa, this study evaluated the effect of CasIII-ia on Leishmania mexicana amastigotes and its potential use as a treatment for cutaneous leishmaniasis in the murine model. METHODS: We analyzed the leishmanicidal effect of CasIII-ia on L. mexicana amastigotes and on their survival in bone marrow-derived macrophages. Furthermore, we evaluated the production of ROS in treated parasites and the efficacy of CasIII-ia in the treatment of mice infected with L. mexicana. RESULTS: Our results show that CasIII-ia reduces parasite viability in a dose-dependent manner that correlates with increased ROS production. A decrease in the size of footpad lesions and in parasite loads was observed in infected mice treated with the intraperitoneal administration of CasIII-ia. CONCLUSIONS: We propose CasIII-ia as a potential drug for the treatment of cutaneous leishmaniasis.