Geriatric cutaneous leishmaniasis: a retrospective analysis of 622 cases.

BACKGROUND: Cutaneous leishmaniasis (CL) is most common in childhood because children are exposed to the parasite early and, unlike adults, do not have immunity to CL. Since CL is less common in geriatric patients, clinical and epidemiological data in this age group are limited. This study aims to compare the clinical and demographic characteristics of geriatric patients diagnosed with CL with young patients. METHODS: In this retrospective study, 622 patients aged 65 and over and 6350 patients aged 19-64, who applied to Sanliurfa Oriental Boil Diagnosis and Treatment Center between January 2013 and February 2024 and were diagnosed with CL by parasitological examination, were included. Clinical and demographic characteristics of patients diagnosed with CL, such as age, gender, location of the lesion, lesion size, duration of the lesion, and treatments applied due to the diagnosis of CL, were recorded. Clinical and demographic characteristics of geriatric and young patients were compared. RESULTS: The mean age of elderly CL cases was 72.95 ± 6.54 years, and 65.2% were female. The most common clinical forms were ulcers (51.9%) and plaques (41%), respectively, in young and elderly patients. The most common locations of the lesions were upper limbs (54.8%) in all patients. The most preferred treatment method was intralesional (IL) meglumine antimoniate (MA) treatment (98.3%) in all patients. There were no difference between young and elderly CL cases in terms of mean number of lesions, average lesion duration, average lesion size, lesion location, clinical forms of lesions, and treatments options (P > 0.05). CONCLUSIONS: Based on the results of our study, it can be said that the clinical and demographic characteristics of CL are similar in young and old patients and systemic MA treatment shows similar clinical benefit in both age groups. In addition, it can be said that systemic MA therapy can be used safely in young patients and elderly patients without contraindications. IL MA therapy can be used in elderly patients where systemic MA therapy is contraindicated.

A Randomized, Controlled, Noninferiority, Multicenter Trial of Systemic vs Intralesional Treatment With Meglumine Antimoniate for Cutaneous Leishmaniasis in Brazil.

BACKGROUND: Meglumine antimoniate (MA) remains the main treatment for cutaneous leishmaniasis (CL). Uncontrolled studies suggest that intralesional MA (IL-MA) may be noninferior and safer than systemic MA (S-MA). METHODS: Multicenter, randomized, controlled, open-label, phase 3 clinical trial to evaluate the efficacy and toxicity of IL-MA in 3 infiltrations at 14-day intervals compared with S-MA (10-20 mg Sb5+/kg/day, 20 days) for CL, with noninferiority margin of 20%. Primary and secondary outcomes were definitive cure at day 180 and epithelialization rate at day 90 of treatment, respectively. A 2-year follow-up was performed to assess relapses and emergence of mucosal lesions. Adverse events (AEs) were monitored according to the Division of AIDS AE grading system. RESULTS: We evaluated 135 patients. The cure rates (95% confidence interval) for IL-MA and S-MA treatment were, respectively, 82.8% (70.5-91.4) and 67.8% (53.3-78.3) per protocol (PP) and 70.6% (58.3-81.0) and 59.7% (47.0-71.5) per intention to treat (ITT). The epithelialization rates of the IL-MA and S-MA treatment were, respectively, 79.3% (66.6-88 + 8) and 71.2% (57.9-82.2) PP and 69.1% (55.2-78.5) and 64.2% (50.0-74.2) ITT. AEs in the IL-MA and S-MA groups were, respectively, clinical, 45.6% and 80.6%; laboratory, 26.5% and 73.1%; and electrocardiogram, 8.8% and 25.4%. Ten participants in the S-MA group and 1 in the IL-MA group were discontinued due to severe or persistent AEs. CONCLUSIONS: IL-MA provides a similar cure rate and results in less toxicity compared with S-MA and may be used as first-line therapy for CL patients. CLINICAL TRIALS REGISTRATION: REBEC: RBR-6mk5n4.

Positivity, diagnosis and treatment follow-up of cutaneous leishmaniasis in war-affected areas of Bajaur, Pakistan.

This study was conducted to explore the frequency of positivity of cutaneous leishmaniasis (CL) in the tribal district Bajaur located near the Pak-Afghan border. The present study was conducted at the Leishmaniasis Center of Headquarter Hospital Khar District Bajaur, Pakistan. In total, 646 patients were recruited and included in the study after ethical approval and consent from the patients. CL was confirmed by taking blood samples from the sides of the lesion and observing them under a microscope using Giemsa staining. Information about demographic factors was collected from the study participants with a questionnaire and analyzed by SPSS. It was found that 73.8% of suspected patients were positive and 26.2% were negative for CL. There were 51.9% male and 48.1% female patients. The most frequently affected site was the face (42.6%), and most of the patients (85.8%) had only one lesion. The positivity of CL was higher among those under age 15 years. The area of most positivity, with 45.2% of the cases, was Tehsil Mamund. Most of the patients (46.6%) lived in stone houses, with 98.6% of patients having domestic animals in their houses. Approximately 198 patients were treated with intramuscular and intralesional injections of meglumine antimoniate, and their weekly follow-up revealed that 48% of patients recovered, while the remaining patients left the course of treatment at different stages of therapy. The positivity of CL is high in this area and is confirmed by the detection of Leishmania amastigotes in the blood collected from their lesions. Socioeconomic factors are the main underlying causes of the rapid spread of this disease and meglumine antimoniate is an effective drug.

Effectiveness of doxycycline for the treatment of zoonotic cutaneous leishmaniasis in vivo.

There are available data on in vivo studies of monotherapy of zoonotic cutaneous leishmaniasis with some antibacterial drugs (doxycycline) and their comparison with meglumine antimoniate (glucantime). We used golden Syrian hamsters as a laboratory model. Experimental groups were formed, each of which was treated with one of the tested drugs. Infection of animals was carried out with Leishmania major promastigotes. We selected highly virulent strains of L. major culture isolated from human ulcers or rodents. Meglumine antimoniate monotherapy and doxycycline monotherapy are quite effective and do not differ by the 30th day of their use in such indicators as the average degree of local damage and the average number of Leishmania in the lesions. The main differences were recorded in terms of average body weight gain and average clinical recovery in favour of doxycycline. Leishmania in the lesion on the 60th day were completely absent in treatment with doxycycline. The experiment proved the effectiveness of doxycycline monotherapy: Leishmania in the lesions were absolutely absent by the end of the treatment.

Antimony resistance associated with persistence of Leishmania (Leishmania) infantum infection in macrophages.

Visceral leishmaniasis is a severe disease caused by protozoan parasites that include Leishmania (L.) infantum. The disease is established when parasites subvert the immune response of the host. Notably, chemotherapy-based use of antimonial compounds can partially alleviate disease burden. Unfortunately, the resistance to drug treatments is increasing in areas endemic to the disease. In this report, we investigated immune responses within macrophages infected with antimony-resistant L. infantum isolates from patients with a relapse in the disease. Results revealed that antimony-resistant parasites persist in the first 24 h of infection. Activation of macrophage or blocking of thiol production during infection shows enhanced clearance of parasites, which is coordinately associated with increased production of pro-inflammatory cytokines. Taken together, these results suggest that the mechanism of antimony resistance in L. infantum isolates may be related to a decrease in macrophage microbicidal functions.

Therapeutic Efficacy of a Mixed Formulation of Conventional and PEGylated Liposomes Containing Meglumine Antimoniate, Combined with Allopurinol, in Dogs Naturally Infected with Leishmania infantum.

The treatment of dogs naturally infected with Leishmania infantum using meglumine antimoniate (MA) encapsulated in conventional liposomes (LC) in association with allopurinol has been previously reported to promote a marked reduction in the parasite burden in the main infection sites. Here, a new assay in naturally infected dogs was performed using a novel liposome formulation of MA consisting of a mixture of conventional and long-circulating (PEGylated) liposomes (LCP), with expected broader distribution among affected tissues of the mononuclear phagocyte system. Experimental groups of naturally infected dogs were as follows: LCP plus Allop, receiving LCP intravenously as 2 cycles of 6 doses (6.5 mg Sb/kg of body weight/dose) at 4-day intervals plus allopurinol at 30 mg/kg/12 h per os (p.o.) during 130 days (LCP+Allop); LC plus Allop, receiving LC intravenously as 2 cycles of 6 doses (6.5 mg Sb/kg/dose) plus allopurinol during 130 days (LC+Allop); Allop, treated with allopurinol only; and a nontreated control. Parasite loads were evaluated by quantitative PCR in liver, spleen, and bone marrow tissue and by immunohistochemistry in the ear skin, before treatment, just after treatment, and 4 months later. The LCP+Allop and LC+Allop groups, but not the Allop group, showed significant suppression of the parasites in the liver, spleen, and bone marrow 4 months after treatment compared to the pretreatment period or the control group. Only LCP+Allop group showed significantly lower parasite burden in the skin in comparison to the control group. On the basis of clinical staging and parasitological evaluations, the LCP formulation exhibited a more favorable therapeutic profile than the LC one, being therefore promising for the treatment of canine visceral leishmaniasis.

Adverse reactions to meglumine antimoniate in Brazilian inpatients with visceral leishmaniases: A case series.

WHAT IS KNOWN AND OBJECTIVES: Adverse drug reactions (ADR) related to the treatment of visceral leishmaniasis (VL) can cause severe clinical complications. We report a case series of ADR in hospitalized VL patients on meglumine antimoniate (MA). CASE DESCRIPTION: Seven cases of patients taking MA had at least one objective evidence for suspected ADR, including electrocardiographic, laboratory or clinical alteration. WHAT IS NEW AND CONCLUSION: Meglumine antimoniate is highly toxic. Adherence to treatment guidelines is important. Pharmacists working in multidisciplinary teams may contribute to early detection and management of MA therapy-related ADR.

Comparative mitochondrial proteomics of Leishmania tropica clinical isolates resistant and sensitive to meglumine antimoniate.

Antimony is an important drug for the treatment of Leishmania parasite infections. In several countries, the emergence of drug-resistant Leishmania species has reduced the effectiveness of this drug. The mechanism of clinical drug resistance is unclear. The aim of this work was to identify mitochondrial proteome alterations associated with resistance against antimonial. A combination of cell fractionation, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and Label-Free Quantification was used to characterize the mitochondrial protein composition of Leishmania tropica field isolates resistant and sensitive to meglumine antimoniate. LC-MS/MS analysis resulted in the identification of about 1200 proteins of the Leishmania tropica mitochondrial proteome. Various criteria were used to allocate about 40% proteins to mitochondrial proteome. Comparative quantitative proteomic analysis of the sensitive and the resistant strains showed proteins with differential abundance in resistance species are involved in TCA and aerobic respiration enzymes, stress proteins, lipid metabolism enzymes, and translation. These results showed that the mechanism of antimony resistance in Leishmania spp. field isolate may be associated with alteration in enzymes involved in mitochondrial pathways.

Study of the in vitro and in vivo antileishmanial activities of nimodipine in susceptible BALB/c mice.

BACKGROUND & OBJECTIVES: Pentavalent antimonials are the standard treatment for cutaneous leishmaniasis (CL), however, treatment failures are frequent. Nimodipine, a calcium channel blocker is known to show promising antiprotozoal effects. Here, we investigated the antileishmanial effect of Nimodipine in both in vitro and in vivo BALB/c mice model of CL. We also compared the in vivo effect with amphotericin B and meglumine antimoniate in the experimental CL mice model. METHODS: Colorimetric alamar blue assay and J774 A.1 mouse macrophage cells were used to determine the effect of nimodipine on promastigotes and amastigotes viability, respectively. Then, the in vivo activity of nimodipine was compared to that of conventional therapies in both the early and established courses of Leishmania major infection in susceptible non-healing BALB/c mice. RESULTS: Nimodipine was highly active against promastigotes and amastigotes of L. major with IC50 values of 49.40 and 15.03 µM, respectively. In the early model, the combination therapy with meglumine antimoniate and nimodipine showed no parasites in the spleen or footpad of animals. The footpad thickness was significantly lower in mice treated with either nimodipine (1 mg/kg or 2.5 mg/kg) or amphotericin B compared to the control group in the established lesions model. However, no complete remission was observed in the footpad lesion of any of the treatment groups (nimodipine, amphotericin B, meglumine antimoniate, and combination therapy). INTERPRETATION & CONCLUSION: The effect of nimodipine was comparable to that of amphotericin B and meglumine antimoniate in early and established CL lesion models. Since nimodipine is more cost-effective than conventional therapies, our results merit further investigation in other animal models and voluntary human subjects.

Dog hepatocytes are key effector cells in the liver innate immune response to Leishmania infantum.

Hepatocytes constitute the majority of hepatic cells, and play a key role in controlling systemic innate immunity, via pattern-recognition receptors (PRRs) and by synthesizing complement and acute phase proteins. Leishmania infantum, a protozoan parasite that causes human and canine leishmaniasis, infects liver by establishing inside the Kupffer cells. The current study proposes the elucidation of the immune response generated by dog hepatocytes when exposed to L. infantum. Additionally, the impact of adding leishmanicidal compound, meglumine antimoniate (MgA), to parasite-exposed hepatocytes was also addressed. L. infantum presents a high tropism to hepatocytes, establishing strong membrane interactions. The possibility of L. infantum internalization by hepatocytes was raised, but not confirmed. Hepatocytes were able to recognize parasite presence, inducing PRRs [nucleotide oligomerization domain (NOD)1, NOD2 and Toll-like receptor (TLR)2] gene expression and generating a mix pro- and anti-inflammatory cytokine response. Reduction of cytochrome P 450s enzyme activity was also observed concomitant with the inflammatory response. Addition of MgA increased NOD2, TLR4 and interleukin 10 gene expression, indicating an immunomodulatory role for MgA. Hepatocytes seem to have a major role in coordinating liver's innate immune response against L. infantum infection, activating inflammatory mechanisms, but always balancing the inflammatory response in order to avoid cell damage.

The activity of encapsulated meglumine antimoniate in stearylamine-bearing liposomes against cutaneous leishmaniasis in BALB/c mice.

Topical treatment of cutaneous leishmaniasis has demonstrated appropriate alternative for reducing toxicity of conventional treatments, improving patients' compliance and reducing treatment costs. Furthermore, outbreak of cutaneous leishmaniasis in war and conflict zones emerges finding an effective, economical and user-friendly treatment. In the context of liposomal topical drug delivery, we developed and characterized meglumine antimoniate (MA) loaded liposomes and investigated their effectiveness in topical treatment of cutaneous leishmaniasis. Previously, we showed the promising use of liposomal formulation of MA in treatment of cutaneous leishmaniasis in BALB/c mice. Here, we included Stearylamine (SA) in liposomes' structure which has antileishmanial activity by itself. . Size and encapsulation efficiency of liposomes were measured and in vitro permeation was performed using mice model. In vitro toxicity of liposomes was measured against leishmania promastigotes and amastigotes. Liposomes were used topically twice a day for 4 weeks to treat leishmania lesions in BALB\c mice model. In vitro permeation study showed liposomal formulations improved the percent of MA permeation compared with MA-cream. Promastigotes and amastigotes assay results showed significant enhanced toxicity in Liposomal-MA containing SA compared to Lip-MA. In BALB\c mice model of cutaneous leishmaniasis, liposomal groups exhibited significantly smaller lesion size compared to control groups (p < 0.01). In addition, the spleen parasite burden was significantly (P < 0.01) lower in mice treated with selected liposomal MA than in mice treated with PBS, control liposomes and MA cream. The results of this study showed that SA-liposomes encapsulated with MA might be useful as a candidate for the topical treatment of CL which merit further investigation.

Safety and efficacy of miltefosine in cutaneous leishmaniasis: An open label, non-comparative study from Balochistan.

BACKGROUND & OBJECTIVE: Cutaneous Leishmaniasis (CL) is endemic in Baluchistan and treated traditionally with Meglumine antimoniate. Miltefosine appears appealing therapy in cutaneous Leishmaniasis. Our objective was to evaluate safety and efficacy of Miltifossine in treatment of cutaneous Leishmaniasis. METHODS: This experimental study was conducted from 10 September 2017 to 10 May 2018 at Combined Military Hospital Quetta. Total of 42 patients were recruited by purposive sampling technique. Lesional skin smears were stained with giemsa for Leishmania amastigotes under magnification (100 x).Complete blood count, serum urea, creatinine, bilirubin, aspartate aminotransferases (AST), alanine aminotransferase (ALT) were done at the beginning of treatment and then weekly, thereafter. Cap Miltefosine 50 mg (2.5mg/kg) were given as directly observed therapy .Daily observation during treatment phase was done for clinical side effects of therapy. Clinical response was documented at two weeks then at eight weeks. Photographs were taken before and after the therapy. Data was analyzed by SPSS 16. RESULTS: Complete clinical response was observed in 39 (92.9%) patients and partial clinical response in 1(2.4%) patient. Two patients were lost to follow up at eight weeks. No significant derangements in laboratory profile were noted before and after treatment. Mean duration of treatment was 23.47+SD 4.44 days. Sixteen patients (38.1%) took Miltefosine for 28 days, 12 (28.6%) for 21 days and 9 (25%) for 25 days. CONCLUSION: Miltefosine is safe and cost effective treatment for cutaneous Leishmaniasis. It is effective in CL cases not susceptible to antimony compounds.

Comparison of Intralesional Meglumine Antimonite along with oral Itraconazole to Intralesional Meglumine Antimonite in the treatment of Cutaneous Leishmaniasis.

BACKGROUND & OBJECTIVE: Cutaneous leishmaniasis (CL) is endemic in developing countries like Pakistan. Pentavalent antimonials are still drug of choice, despite being toxic and intolerable for patients. Second line treatments have been extensively studied but the results of their efficacy are conflicting. This, to our knowledge, will be the first study in this regard. Our objective was to determine if combination of oral itraconazole with intralesional (IL) meglumine antimoniate (MA) reduces the duration of treatment for cutaneous leishmaniasis, as compared to intralesional MA alone. METHODS: A randomized controlled trial (single blinded) was carried out from August 2017 till December 2017 on 69 patients who fulfilled inclusion criteria. They were assigned to Group-A or B by lottery method. Group-A patients received IL MA once a week while Group-B received oral itraconazole 200mg, once daily, for six weeks along with similar regimen of IL MA as Group-A. The patients were assessed every three weeks by the blinded assessor till clinical cure was achieved. A follow up visit, two months after clinical cure was done to look for relapse of the disease. RESULTS: Thirty patients in Group-A and 35 patients in Group-B completed the study. At 3, 6, 9 and 12 weeks the patients were assessed for: no, partial or complete response and results of the two groups were compared for statistical significance. The p-values of 0.20, 0.57 and 0.11 at 3, 6 and 9 weeks, respectively, depict that there was no significant difference at any step of assessment between the two groups in terms of healing. The p values of each t test was>0.05 refuting the hypothesis. CONCLUSION: Combination of oral itraconazole with intralesional MA offered no benefit over intralesional MA alone in the management of cutaneous leishmaniasis in terms of duration of therapy.

The effect of Nd:YAG laser therapy on cutaneous leishmaniasis compared to intralesional meglumine antimoniate.

INTRODUCTION: Nd:YAG laser is one of the commonly used lasers in dermatology. AIM: This study aimed to investigate the effect of Nd:YAG laser therapy (NDY) on cutaneous leishmaniasis in comparison with meglumine antimoniate (MA). Therefore, researchers are seeking to use a more effective, faster and less complicated method. MATERIAL AND METHODS: This study was conducted as a clinical trial on 16 patients with cutaneous leishmaniasis treated simultaneously as follows: one lesion with Glucantime and another with NDY laser in the Ahvaz Jundishapur University of Medical Sciences in 2016-2017. Then, the demographic data, number of treatment sessions, mean duration of illness before the start of treatment, post inflammatory hyperpigmentation (PIH), and scars, and recovery in two methods were recorded and compared using SPSS-21. RESULTS: The mean age was 14.37 ±29.68. The mean duration of disease before the study was 1.84 ±0.50 months. The mean number of Glucantime injections was 7.31 ±4.01 and the mean number of laser therapy sessions was 2.56 ±0.89; this was significantly less than that of injections of the MA group (p < 0.001). Moreover, the MA scars were observed in 10 subjects and laser scars were seen in 3 subjects. Scars in patients treated with laser were significantly smaller than in those treated with Glucantime injections (p = 0.03). 13 subjects had MA therapy-induced PIH and 15 had laser therapy-induced PIH. CONCLUSIONS: The alternative method of laser use in the treatment of patients with cutaneous leishmaniasis can lead to complete recovery of patients in shorter time and with less complications.

Efficacy of Meglumine Antimoniate in a Low Polymerization State Orally Administered in a Murine Model of Visceral Leishmaniasis.

Progress toward the improvement of meglumine antimoniate (MA), commercially known as Glucantime, a highly effective but also toxic antileishmanial drug, has been hindered by the lack of knowledge and control of its chemical composition. Here, MA was manipulated chemically with the aim of achieving an orally effective drug. MA compounds were synthesized from either antimony pentachloride (MA-SbCl5) or potassium hexahydroxyantimonate [MA-KSb(OH)6] and prepared under a low polymerization state. These compounds were compared to Glucantime regarding chemical composition, permeation properties across a cellulose membrane and Caco-2 cell monolayer, and uptake by peritoneal macrophages. MA-SbCl5 and MA-KSb(OH)6 were characterized as less polymerized and more permeative 2:2 Sb-meglumine complexes than Glucantime, which consisted of a mixture of 2:3 and 3:3 Sb-meglumine complexes. The antileishmanial activities and hepatic uptake of all compounds were evaluated after oral administration in BALB/c mice infected with Leishmania infantum chagasi, as a model of visceral leishmaniasis (VL). The synthetic MA compounds given at 300 mg Sb/kg of body weight/12 h for 30 days significantly reduced spleen and liver parasite burdens, in contrast to those for Glucantime at the same dose. The greater activity of synthetic compounds could be attributed to their higher intestinal absorption and accumulation efficiency in the liver. MA-SbCl5 given orally was as efficacious as Glucantime by the parenteral route (80 mg Sb/kg/24 h intraperitoneally). These data taken together suggest that treatment with a less-polymerized form of MA by the oral route may be effective for the treatment of VL.

Vascular apoptosis associated with meglumine antimoniate: In vivo investigation of a chick embryo model.

The vasculo-toxic effect of meglumine antimoniate (MA) was confirmed in our previous investigation. The current study investigates the association of this effect with altered VEGF-A and VEGF-R2 expression. Additional mechanisms by which MA causes vascular toxicity are not clearly understood. We hypothesized that MA may alter normal expression of apoptotic genes and cause vascular toxicity. The current investigation was designed to address this issue using a chick embryo model. Fertile chicken eggs were treated with MA and the extra-embryonic membrane (EEM) vasculature was evaluated by morphometric, molecular and immunohistochemistry assays. The results showed that MA not only altered apoptotic gene expression, but that this alteration may disturb the normal development of the vascular network and cause embryo malformation. The relative expression level of the CASP3, CASP7, CASP9, APAF1, AIF1 and TP53 genes increased in drug-exposed EEMs. In addition, IHC assay confirmed the low expression BCL2 and increased expression of Bax, which are associated with a high rate of apoptosis. We suggest that induction of an apoptotic signaling pathway can lead to vascular defects during embryo development and the consecutive cascade of events can lead to the embryo malformation.

Plasma antimony determination during cutaneous leishmaniasis treatment with intralesional infiltration of meglumine antimoniate.

OBJECTIVES: To evaluate the antimony (Sb) in plasma of patients who underwent a standardised meglumine antimoniate (MA) intralesional infiltration protocol for cutaneous leishmaniasis treatment. METHODS: The level of Sb in plasma was determined by atomic absorption spectroscopy, before and 1, 2, 4 and 6 hours after the first intralesional infiltration of MA to determine the parameters peak concentrations (C1 h ), area under curve of drug concentration in plasma from zero to 6 h (AUC0-6 h ) and elimination half-life (t½) of Sb. Blood samples were also collected weekly during the treatment period, always before infiltration. RESULTS: Fourteen patients underwent MA intralesional infiltration with doses ranging from 0.8 to 9 mg Sb/kg at the first infiltration. The C1 h ranged from 3850 to 47 095 mg × h/L and was the highest concentration obtained for 11 of 14 patients after the first intralesional infiltration of MA. A rapid initial phase of distribution lasting up to 4 h (2.6 ± 0.34 h) was followed by a slower elimination phase. Total skin lesion area, C1 h and AUC(0-6 h) were related to the dose of Sb infiltered (P < 0.05). Plasma Sb in samples collected weekly before the infiltration revealed antimony concentrations below the quantification limit (15.0 µg Sb/l) during the treatment period. CONCLUSIONS: Sb is quickly absorbed and eliminated after intralesional administration of MA, in a pattern similar to that reported with the Sb systemic administration. Using a therapeutic schedule limited to weekly intralesional infiltration of doses <10 mg Sb/kg does not result in plasma Sb accumulation.

Sinergism between alkaloids piperine and capsaicin with meglumine antimoniate against Leishmania infantum.

The primary choice of drugs to treat Leishmaniasis are the pentavalent antimony-based compounds, nevertheless these drugs presented undesirable side effects. However, safe natural compounds could be used in combination with these drugs to enhance their activity. The aim of this study was to evaluate the sinergism of capsaicin and piperine, isolated from Capsicum frutescens and Piper nigrum, respectively, in combination with meglumine antimoniate against Leishmania infantum promastigote and amastigote forms. Each compound was mixed with the standard drug in several percentage mixtures and tested at various concentrations. Capsaicin and piperine in combination with meglumine antimoniate (25% + 75%) showed better anti-leishmanial activity with EC50 = 4.31 ±â€¯0.44 e 7.25 ±â€¯4.84 µg/mL against promastigote and amastigote forms, respectively. The results point that these spice alkaloids are suitable compounds to be administered in combinations with antileishmanial drugs to improve their action.

Antileishmanial Activity of 2-Methoxy-4H-spiro-[naphthalene-1,2'-oxiran]-4-one (Epoxymethoxy-lawsone): A Promising New Drug Candidate for Leishmaniasis Treatment.

Epoxymethoxylawsone is a naphthoquinone derivative promising as drug candidate for the treatment of leishmaniases. In the present work the effectiveness of epoxymethoxylawsone, and meglumine antimoniate on Leishmania (Leishmania) amazonensis parasites and on mice paw lesions of infected BALB/c mice was assessed. In an intracellular amastigotes assay, the half-maximal inhibitory concentration (IC50) value for epoxymethoxylawsone was slightly higher (1.7-fold) than that found for meglumine antimoniate. The efficacy of both drugs became more evident after 48 h of exposure when either the oxirane compound and reference drug reached 18-fold and 7.4-fold lower IC50 values (0.40 ± 0.001 µM and 0.60 ± 0.02 µM), respectively. Promastigotes were also affected by epoxymethoxylawsone after 24 h of incubation (IC50 = 45.45 ± 5.0 µM), but with IC50 6-fold higher than those found for intracellular amastigotes. Cytotoxicity analysis revealed that epoxymethoxylawsone (CC50 = 40.05 ± µM) has 1.7-fold higher effects than meglumine antimoniate (CC50 = 24.14 ± 2.6 µM). Treatment of the paw lesion in infected BALB/c mice with epoxymethoxy-lawsone led to a significant 27% reduction (p < 0.05) of the lesion size, for all administrated doses, compared to the control group. Lesion reduction was also detected after mice treatment with meglumine antimoniate, reaching 31.0% (0.23 mg of Sb(V)/Kg/day and 2.27 mg of Sb(V)/Kg/day) and 64.0% (22.7 mg of Sb(V)/Kg/day). In addition, mice lesion ultrastructural changes were evidenced in amastigotes. The set of data gathered here indicate that epoxymethoxylawsone has pronounced effects on parasites and merits furthering to the preclinical stage.

Mixed Formulation of Conventional and Pegylated Meglumine Antimoniate-Containing Liposomes Reduces Inflammatory Process and Parasite Burden in Leishmania infantum-Infected BALB/c Mice.

Pentavalent antimonial has been the first choice treatment for visceral leishmaniasis; however, it has several side effects that leads to low adherence to treatment. Liposome-encapsulated meglumine antimoniate (MA) arises as an important strategy for chemotherapy enhancement. We evaluated the immunopathological changes using the mixture of conventional and pegylated liposomes with MA. The mice were infected with Leishmania infantum and a single-dose treatment regimen. Comparison was made with groups treated with saline, empty liposomes, free MA, and a liposomal formulation of MA (Lipo MA). Histopathological analyses demonstrated that animals treated with Lipo MA showed a significant decrease in the inflammatory process and the absence of granulomas. The in vitro stimulation of splenocytes showed a significant increase of gamma interferon (IFN-γ) produced by CD8+ T cells and a decrease in interleukin-10 (IL-10) produced by CD4+ and CD8+ T cells in the Lipo MA. Furthermore, the Lipo MA group showed an increase in the IFN-γ/IL-10 ratio in both CD4+ and CD8+ T cell subsets. According to the parasite load evaluation using quantitative PCR, the Lipo MA group showed no L. infantum DNA in the spleen (0.0%) and 41.4% in the liver. In addition, we detected a low positive correlation between parasitism and histopathology findings (inflammatory process and granuloma formation). Thus, our results confirmed that Lipo MA is a promising antileishmanial formulation able to reduce the inflammatory response and induce a type 1 immune response, accompanied by a significant reduction of the parasite burden into hepatic and splenic compartments in treated animals.