Visceral Leishmaniasis Infection Research Articles

Targeted Immunology for Prevention and Cure of VL

Leishmaniasis is a neglected tropical disease caused by a group of protozoan parasites of the genus Leishmania. Clinical presentation of leishmaniasis can range from cutaneous, mucocutaneous, or visceral forms depending on the parasite species. Visceral leishmaniasis (VL) caused by L. donovani and L. infantum is the severest and one of the deadliest parasitic diseases of the tropics second only to malaria (1). Nearly, 20,000‐40,000 annual deaths are estimated due to this disease (2). Except for the Indian subcontinent and West Africa, VL is frequent in dogs, which serve as the major reservoir for zoonosis (3). Transmitted by the bite of an infected sandfly, Leishmania endure in the phagolysomal compartment of macrophages by evasion and attenuation of the microbicidal functions of the host (4, 5). Leishmania has evolved as a successful parasite chiefly by its ability to modulate the immunological and cyto-chemical responses of the host following infection. The key strategy for successful pathogenesis is to subvert the nitric oxide burst in the host macrophage. This opportunistic parasite thus establishes a safe niche in the inactivated phagocyte and uncontrolled parasitization in liver, spleen, and bone marrow leads to symptomatic VL characterized by fever, weight loss, hepatosplenomegaly, and anemia (3). Since the pathogenesis of the disease is based on subversion and modulation of both innate and adaptive arms of immunity, the disease is opportunistic to immuno-suppression (6). Hence, commencement of an appropriate immune response is a challenge for the control of VL infection. Indeed, therapeutic drugs like SSG and miltefosine are immuno-modulators that trigger Th1 responses essential for activation of oxidative burst in the macrophages (7, 8). However, major limitations of narrow therapeutic index and increasing incidence of resistance with currently used drugs for VL are encumbrances in effective disease management. Recent approaches like combination therapy, targeted delivery, and use of immune-adjunct are efforts to bring down the effective doses of these toxicity-associated drugs. Most promising are the prospects of various immune-targeted therapeutic approaches for treatment of VL (9). Various leishmanial antigens, cytokines, and antibodies that initiate protective Th1-biased cell-mediated immune responses used singly or as an adjunct to conventional chemotherapy are potent immuno-chemotherapeutic agents for the cure of VL (10, 11). Additionally, medicinal plants and their products have opened new dimensions in search of safer and cheaper anti-leishmanial immuno-modulators. These phytochemicals are not only promising as immuno-chemotherapeutic agents against VL but also have potential as immuno-adjuvants and adjuncts to chemotherapy for a number of other immuno-regulatory diseases (12). Since both cure and resilience to Leishmania infection depend on the immunological status of the host, the antigens that can trigger healing responses can also induce prophylactic immunity. Therefore, identification of immunogens that can induce Th1 responses is the critical aspect of vaccine search against VL (13). Although a number of defined antigens have been reported to impart protective immunity against experimental VL, recent trend of reverse vaccinology is a promising aspect for identification of key immunogens for a successful vaccine (13, 14). This requires rational inputs and algorithm for identification of a promising antigen from the whole proteome data analysis in silico (15). One of the key inputs is to identify the epitopes for activation of both CD4 C Th1 and CD8 C T cells.

Factors Associated with Visceral Leishmaniasis Infection in North Gondar Zone, Amhara Region, North West Ethiopia, Case Control Study

Background: Leishmaniasis is becoming a major public health problem both in terms of geographical spread and incidence. Visceral leishmaniasis, the worst form among its clinical forms, is the second largest cause of parasite related death responsible for 500,000 new cases each year. No or few risk factor data is available in North Gondar zone on this deadly disease. Objective: To assess determinants of visceral leishmaniasis in North Gondar Zone, North West Ethiopia. Methods: Facility based unmatched case-control study was employed from September 1-30, 2013. Samples of 545 case control pairs were included using consecutive sampling technique. Data was collected using pretested structured questionnaire; entered into EpiData version 3.1 and exported to SPSS version 16.0 for analysis. Crude and adjusted odds ratio with 95% CI was calculated to determine the strength of association between response and predictor variables. P-value less than 0.05 were considered as a level of significance. Result: Male sex (OR=4.64; 95%CI=2.29, 9.39) and age below 15 years (OR=3.26; 95%CI=1.54, 6.92) were positively associated with visceral leishmaniasis infection. Mud wall (OR= 2.49; 95%CI=1.12, 5.58), presences of dog (OR=4.41; 95%CI= 2.25, 8.62), termite hills (OR=3.04; 95%CI=1.59, 5.81) and acacia trees (OR=3.19; 95%CI=1.70, 5.99) increased the risk of infection. Outdoor sleeping (OR=6.28; 95%CI= 3.41, 11.55) was also associated with higher risk of infection. HIV infection (OR=3.28; 95%CI=1.45, 7.39) and malnutrition (OR=2.92; 95%CI=1.55, 5.51) were associated with higher risk of infection. Conclusion: Male gender and being below 15 years of age were positive socio-demographic determinants of visceral leishmaniasis. House made with mud wall was among the associated factors. Presence of dog, termite hills and acacia trees were also important risk factors. Outdoor sleeping was positively associated with visceral leishmaniasis. HIV and malnutrition were also important predictors of the disease. Therefore, the risk of infection can be reduced by improving housing condition, sleeping indoor above ground, making residential area free and far from termite hills and acacia tree. The role of peridomestic animals should also be investigated.

Comparative proteomics and glycoproteomics of plasma proteins in Indian visceral leishmaniasis

BackgroundVisceral leishmaniasis (VL) is a deadly parasitic diseases caused by Leishmania donovani; it is a major health problem in many countries. A lack of proper understanding of the disease biology, poor diagnostic methods and increasing drug resistance are the main reasons for the growing burden of VL infection. Comparative plasma proteomics are a relatively useful technique that can be used to investigate disease-associated alterations that can help in understanding host responses against pathogens, and might be useful in disease management and diagnosis.ResultIn this study, a comparative proteomics and glycoproteomics approach using 2DE and 2D-DIGE was employed between early diagnosed VL patients of all age groups and healthy endemic and non-endemic controls in order to aid the recognition of disease-associated alterations in host plasma. Comparative proteomics was performed by the depletion of seven highly abundant plasma proteins. Comparative glycoproteomics was performed by the depletion of albumin and IgG, followed by purification of plasma glycoproteins using a multi lectin affinity column. From these two approaches, 39 differentially expressed protein spots were identified and sequenced using MALDI-TOF/TOF mass spectrometry. This revealed ten distinct proteins that appeared in multiple spots, suggesting micro-heterogeneity. Among these proteins, alpha-1-antitrypsin, alpha-1-B glycoprotein and amyloid-A1 precursor were up-regulated, whereas vitamin-D binding protein, apolipoprotein-A-I and transthyretin were down-regulated in VL. Alterations in the levels of these proteins in VL-infected plasma were further confirmed by western blot and ELISA.ConclusionsThese proteins may be involved in the survival of parasites, resisting neutrophil elastase, and in their multiplication in macrophages, potentially maintaining endogenous anti-inflammatory and immunosuppressive conditions. Consequently, the results of this study may help in understanding the host response against L.donovani, which could help in the discovery of new drugs and disease management. Finally, these alterations on protein levels might be beneficial in improving early diagnosis considering those as biomarkers in Indian VL.Electronic supplementary materialThe online version of this article (doi:10.1186/s12953-014-0048-z) contains supplementary material, which is available to authorized users.

Visceral leishmaniasis: a One Health approach

LEISHMANIASIS is a vectorborne, protozoan disease caused by infection with Leishmania species transmitted by infected phlebotomine sandflies. This article focuses on visceral leishmaniasis, which results in the most severe clinical...

Higher parasite burden In asymptomatic individuals In endemic areas of visceral leishmaniasis

Background: In an area endemic for Visceral Leishmaniasis (VL), subclinical or asymptomatic infections play a crucial role in progression of disease. We determined the parasite load by quantitative PCR (qPCR) in healthy infected population living in an area endemic for Visceral Leishmaniasis. We enrolled 13366 persons from 11 villages of highly endemic region of Bihar, India. Methods & Materials: We conducted two sero-surveys by rK-39 ELISA and DAT with 1 year time interval for identification of incident infected healthy (Asymptomatic) individuals. Parasite load by using TaqMan based qPCR were done on peripheral blood using kDNA specific primers and probe on these sero-converted individuals and its matched control populations. Individuals having parasite load greater than 1 genome/ml of blood was considered as positive by qPCR. Follow-up visit to the homes of each individual were made to monitor the disease conversion in this cohort. Results: Between seroconversion and qPCR were accessed by kappa value. Total 235 persons were converted their serology within 12 month intervals. Of these 235 sero-converters 105 (44.6%) individuals were also positive by qPCR. However, similar number of controls groups (87/237, 37%) also showed positivity by qPCR. The agreement between sero-converter and qPCR was poor (k = 0.12). And among all individuals only one was progress to disease. Conclusion: So there is no major difference in qPCR result between sero-negatives and sero-converters and among all individuals only one were converted into disease that has parasite load 146 parasite genome/ml of blood. These findings suggest the usefulness of parasite load in healthy individuals living in an endemic area of Bihar and contribute as a good tool for VL elimination programme.

Crucial CD8+ T-lymphocyte cytotoxic role in amphotericin B nanospheres efficacy against experimental visceral leishmaniasis

This work aims to develop poly(d,l-lactide-co-glycolide) (PLGA)-nanospheres containing amphotericin B (AmB) with suitable physicochemical properties and anti-parasitic activity for visceral leishmaniasis (VL) therapy. When compared with unloaded-PLGA-nanospheres, the AmB-loaded PLGA-nanospheres displayed an increased particle size without affecting the polydispersity and its negative surface charge. AmB stability in the PLGA-nanospheres was >90% over 60-days at 30°C. The AmB-PLGA-nanospheres demonstrated significant in vitro and in vivo efficacy and preferential accumulation in the visceral organs. In addition, an immune-modulatory effect was observed in mice treated with AmB-PLGA-nanospheres, correlating with improved treatment efficacy. The in vitro cytotoxic response of the T-lymphocytes revealed that AmB-PLGA-nanospheres efficacy against VL infection was strictly due to the action of CD8+- but not CD4+-T lymphocytes. Overall, we demonstrate a crucial role for CD8+ cytotoxic T lymphocytes in the efficacy of AmB-PLGA nanospheres, which could represent a potent and affordable alternative for VL therapy. From the Clinical EditorThis study demonstrates a crucial role for CD8+ T lymphocytes in eliminating visceral leishmaniasis in a murine model by enhancing the cytotoxic efficacy of CD8+ T-cells via amphotericin-B-PLGA nanospheres, paving a way to a unique, potentially more potent and cost-effective therapeutic strategy.

CASE STUDY OF A PATIENT WITH HIV-AIDS AND VISCERAL LEISHMANIASIS CO-INFECTION IN MULTIPLE EPISODES

SUMMARYReport of a 45-year-old male farmer, a resident in the forest zone of Pernambuco, who was diagnosed with human immunodeficiency virus (HIV) in 1999 and treated using antiretroviral (ARV) drugs. In 2005, the first episode of visceral leishmaniasis (VL), as assessed by parasitological diagnosis of bone marrow aspirate, was recorded. When admitted to the hospital, the patient presented fever, hepatosplenomegaly, weight loss, and diarrhea. Since then, six additional episodes of VL occurred, with a frequency rate of one per year (2005-2012, except in 2008). In 2011, the patient presented a disseminated skin lesion caused by the amastigotes of Leishmania, as identified by histopathological assessment of skin biopsy samples. In 2005, he was treated with N-methyl-glucamine-antimony and amphotericin B deoxycholate. However, since 2006 because of a reported toxicity, the drug of choice was liposomal amphotericin B. As recommended by the Ministry of Health, this report emphasizes the need for HIV patients living in VL endemic areas to include this parasitosis in their follow-up protocol, particularly after the first infection of VL.

NTDs V.2.0: “Blue Marble Health”—Neglected Tropical Disease Control and Elimination in a Shifting Health Policy Landscape

The concept of the neglected tropical diseases (NTDs) was established in the aftermath of the Millennium Development Goals. Here, we summarize the emergence of several new post-2010 global health documents and policies, and how they may alter the way we frame the world's major NTDs since they were first highlighted. These documents include a new Global Burden of Disease 2010 Study that identifies visceral leishmaniasis and food-borne trematode infections as priority diseases beyond the seven NTDs originally targeted by preventive chemotherapy, a London Declaration for access to essential medicines, and a 2013 World Health Assembly resolution on NTDs. Additional information highlights an emerging dengue fever pandemic. New United Nations resolutions on women and the non-communicable diseases (NCDs) have not yet embraced NTDs, which may actually be the most common afflictions of girls and women and represent a stealth cause of NCDs. NTDs also have important direct and collateral effects on HIV/AIDS and malaria, and there is now a robust evidence base and rationale for incorporating NTDs into the Global Fund to Fight AIDS, Tuberculosis, and Malaria. “Blue marble health” is an added concept that recognizes a paradoxical NTD disease burden among the poor living in G20 (Group of Twenty) and other wealthy countries, requiring these nations to take greater ownership for both disease control and research and development. As we advance past the year 2015, it will be essential to incorporate global NTD elimination into newly proposed Sustainable Development Goals.

Co–infection of visceral leishmaniasis and pulmonary tuberculosis: a case study

Co–infection of visceral leishmaniasis and pulmonary tuberculosis are increasing public health problem in eastern region of country. A large number of clinical cases of leishmaniasis and tuberculosis have been reported in Sudan. Such type of co-infections lead to decreased host's immune system. This is a case report of 48 years old male with visceral leishmaniasis and pulmonary tuberculosis. He arrived at hospital with complaints of fever with rigor, abdominal pain, weakness, loss of appetite, yellowish discoloration of urine and sclerosis at lower back. Bone marrow aspiration cytology revealed the presence of Leishmania donovani bodies (2+). His treatment was initiated with amphotericin B deoxycholate (inj. Fungizone) 15 infusions on alternate days with 5% dextrose. He had 20 years past history of pulmonary tuberculosis. His chest X-ray showed increased bronchovascular marking encysted pleural effusion on lower segment of right lung. Ultrasonography guided fine needle aspiration cytology of pleural fluid for protein, sugar, lactate dehydrogenase, adenosine deaminase, cell type and cell count. Cytological reports confirmed pulmonary tuberculosis. Antitubercular therapy (four drug regimen: rifampicin, isoniazid, ethambutal, and pyrazinamide) was started. Co-infection of visceral leishmaniasis and pulmonary tuberculosis is a real threat in developing countries. There is a need of cost effective diagnostic and therapeutic facilities for these co-infections.

Emergence of co-infection of visceral leishmaniasis in HIV-positive patients in northeast Iran: A preliminary study

Visceral leishmaniasis (VL) serosurvey was carried out on 49 HIV/AIDS patients among 500 asymptomatic HIV/infected patients who registered in the Khorasan Razavi Province during the last 14 years. HIV infections were detected by ELISA and confirmed using western blot assay at the AIDS centre of the Khorasan Razavi Province. All collected sera were screened using the direct agglutination test (DAT). The sera with anti-Leishmania infantum antibodies at a titre of 1:100 were considered positive for VL infection and serum titration was performed from 1:100 to 1:102,400. Nine (18.4%) patients were sero-positive according to DAT. The distribution of sera titrations were as follows: 1:100 (n = 6) 1:1600 (n = 1); 1:25,600 (n = 1) and 1:102,400 (n = 1). All sero-positive cases showed clinical signs and symptoms. The most predominant signs and symptoms of co-infection of visceral leishmaniasis in HIV-positive patients were pneumonia (n = 2), hepatosplenomegaly (n = 2), lymphadenopathy (n = 2), anaemia (n = 1), prolonged fever (n = 1) and cachexia (n = 1). Our finding shows that VL (or kala-azar) is an opportunistic disease in HIV-positive patients that may be occurred in VL endemic areas of Iran.

Epidemiology of human immunodeficiency virus-visceral leishmaniasis-co-infection

In Brazil, the rates of mother-to-child-transmission (MTCT) of human immunodeficiency virus (HIV) decreased from 20% to 1-2% in some regions. However, the country contains 90% of individuals infected with visceral leishmaniasis (VL) in Latin America, and the west region of São Paulo state faces an alarming expansion of the disease. We describe the epidemiological aspects of the expanding infection of VL and a case report of an HIV-VL-co-infected child from the west region of São Paulo state. The patient was an AIDS-C3 with low levels of CD4, high viral load, severe diarrhea, oral and perineal candidiasis, severe thrombocytopenia, and protein-caloric malnourishment. She evolved with sepsis, renal and cardiac failure. An rK rapid diagnosis test, indirect fluorescent antibody test (IFAT), and bone marrow aspirate were performed for VL. Her symptoms improved significantly after liposomal amphotericin B administration. From the 45 municipalities that compose the Regional Health Department of Presidente Prudente, Lutzomyia longipalpis vectors were found in 58% of them. VL infected dogs were found in 33% of those municipalities, infected dogs and humans were found in 29%, 20% are starting and 33% of the municipalities are preparing VL investigation. It is likely, in this patient, that VL advanced the clinical progression of the HIV disease and the development of AIDS severity. Supported by favorable conditions, the region becomes a new frontier of VL in Brazil.

Measurement of protein and albumin/globulin ratio in patients infected with visceral leishmaniasis

The study included 30 serum samples from people (age: 1-12 years) suffering from visceral leishmaniasis (Leishmania donovani) infection, which were collected from the Central Health Laboratories, and a similar number of healthy controls.The serum level of total protein, albumin and globulin was measured, and fractions of globulin (alpha 1 globulin, alpha 2 globulin, beta globulin, gamma globulin) were also analyzed.The results showed a significant increase (P ≤ 0.05) in total protein of patients (82.27 vs. 57.75 g/L), as compared with controls, while there was a non-significant decrease in the level of albumin (30.63 vs. 31.66 g/L). A similar significant increased level of globulin was also observed in patients (51.63 vs. 24.83 g/L), and the fractions of globulin (alpha 1 globulin, alpha 2 globulin, beta globulin, gamma globulin) were similarly increased (6.01, 13.20, 10.37,21.64 vs. 3.74, 6.63, 7.06, 7.50 g/L, respectively). Accordingly, the albumin:globulin ratio was decreased in patients as compared with controls (0.62 vs. 1.20).

Correction: Arginase Activity in the Blood of Patients with Visceral Leishmaniasis and HIV Infection

The affiliation for Dr. Tamrat Abebe was incomplete and should include an additional institution. The correct affiliation is as follows: 1. Department of Microbiology, Immunology and Parasitology , School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia 2. Department of Biochemistry, WHO Immunology Research and Training Center, University of Lausanne, Lausanne, Switzerland

Arginase Activity in the Blood of Patients with Visceral Leishmaniasis and HIV Infection

BackgroundVisceral leishmaniasis is a parasitic disease associated with high mortality. The most important foci of visceral leishmaniasis in Ethiopia are in the Northwest and are predominantly associated with high rates of HIV co-infection. Co-infection of visceral leishmaniasis patients with HIV results in higher mortality, treatment failure and relapse. We have previously shown that arginase, an enzyme associated with immunosuppression, was increased in patients with visceral leishmaniasis and in HIV seropositive patients; further our results showed that high arginase activity is a marker of disease severity. Here, we tested the hypothesis that increased arginase activities associated with visceral leishmaniasis and HIV infections synergize in patients co-infected with both pathogens.Methodology/Principal FindingsWe recruited a cohort of patients with visceral leishmaniasis and a cohort of patients with visceral leishmaniasis and HIV infection from Gondar, Northwest Ethiopia, and recorded and compared their clinical data. Further, we measured the levels of arginase activity in the blood of these patients and identified the phenotype of arginase-expressing cells. Our results show that CD4+ T cell counts were significantly lower and the parasite load in the spleen was significantly higher in co-infected patients. Moreover, our results demonstrate that arginase activity was significantly higher in peripheral blood mononuclear cells and plasma of co-infected patients. Finally, we identified the cells-expressing arginase in the PBMCs as low-density granulocytes.ConclusionOur results suggest that increased arginase might contribute to the poor disease outcome characteristic of patients with visceral leishmaniasis and HIV co-infection.

Prevalence of kala-azar infection in Pokot county, Amudat district, Northeastern Uganda

Introduction: Visceral leishmaniasis (kala-azar) caused by Leishmania donovani and transmitted by the sand-fly Phlebotomus martini is endemic in certain foci in north-eastern Uganda where it is thought to be confined to Pokot county, Amudat district. Amudat hospital records (April 1998-March 1999) indicated that kala-azar accounted for about 17% of hospital in-patients. However the actual prevalence of kala-azar infection in the community in Pokot county is unknown. This lack of information limits efforts geared towards its control. Objective: To determine the prevalence of kala-azar infection in Pokot county. Methods: A cross-sectional study was conducted in Pokot county in March 2010. The study participants were ≥ 5 years and were randomly selected from the age and sex strata in the chosen clusters. A questionnaire that elicited demographic profiles of participants was used for data collection. Standard procedure for direct agglutination test using blood samples collected from participants on blotting papers was performed. Data was entered in EPIINFO 3.3 and exported to STATA 10, where descriptive statistics were generated. Results: The overall prevalence of kala-azar infection in Pokot county was 17.2% but the prevalence of symptomatic infection in the community was 2.5%. The ratio of symptomatic to asymptomatic kala-azar was 1:6. Loroo sub-county had the highest prevalence of kala-azar infection followed by Karita and Amudat sub-counties at 31.9%, 14.6% and 5.3%, respectively. Conclusion: With kala-azar infection prevalence at 17.2% in the community, there is an urgent need to institute control program spearheaded by ministry of health, in the region. Furthermore, recent reports of cases from other districts within the region, the heterogeneous distribution of infection within the county and the current risk factors, including the role of animals in kala-azar transmission in this area need to be evaluated.

Prevalence of Asymptomatic Visceral Leishmaniasis among under 5 Years Contacts of Confirmed Cases in Thiqar Governorate, 2012

Introduction: Visceral leishmaniasis (VL) or Kala-Azar is a life-threatening parasitic infection. There is evidence that in endemic areas of VL only about 20% of the subjects infected by Leishmania will develop symptomatic VL. The majority of the infected individuals have a sub-clinical infection that may remain completely asymptomatic. In Iraq, no data about asymptomatic VL are available although they are valuable to complete the epidemiological picture of the disease and help evaluating current control measures. Methods: Screening of children of close family contacts and neighborhood contacts of 50 confirmed VL cases was done to determine the prevalence of asymptomatic infection among the contacts. Five children aged less than five years were selected from the same house or the immediately close neighborhood, making a total of 250 children. rk39 was used as a screening test; those with positive result were confirmed by Indirect Immunoflurecent Test (IFAT). All confirmed cases were followed for the maximum incubation period (six months); if symptoms developed during this period, the case was considered as “latent VL”, otherwise it was considered as “asymptomatic VL”. Results: The prevalence of asymptomatic infection was 34.4%. All those tested positive for rk39 were tested positive for IFAT. The prevalence was significantly higher in household than neighborhood contacts, and in those living in mud-made houses than those living in block-made or mixed houses (p<0.05). None of seropositive contacts progressed into latent symptomatic case. Conclusion: It was concluded that asymptomatic VL infections are frequent in Thiqar province and those living in the same case house and mud-made houses are at higher risk to contract infection.

Unresponsiveness ofMycobacterium wvaccine in managing acute and chronicLeishmania donovaniinfections in mouse and hamster

The role of Mycobacterium w (Mw) vaccine as an immunomodulator and immunoprophylactant in the treatment of mycobacterial diseases (leprosy and pulmonary tuberculosis) is well established. The fact that it shares common antigens with leishmanial parasites prompted its assessment as an immunostimulant and as an adjunct to known anti-leishmanials that may help in stimulating the suppressed immune status of Leishmania donovani-infected individuals. The efficacy of Mw vaccine was assessed as an immunomodulator, prophylactically either alone or in combination with anti-leishmanial vaccine, as well as therapeutically as an adjunct to anti-leishmanial treatment in L. donovani-infected hamsters, representing a chronic human Visceral Leishmaniasis (VL) model. Similarly, its efficacy was also evaluated in L. donovani-infected BALB/c mice, representing an acute VL model. The preliminary studies revealed that Mw was ineffective as an immunostimulant and/or immunoprophylactant in hamsters infected with L. donovani, as estimated by T-cell immunological responses. However, in the BALB/c mice-VL model it appeared as an effective immunostimulant but a futile prophylactic agent. It is therefore inferred that, contrary to its role in managing tuberculosis and leprosy infections, Mw vaccine has not been successful in controlling VL infection, emphasizing the need to find detailed explanations for the failure of this vaccine against the disease.

Development and Characterization of Amphotericin B Loaded Solid Lipid Nanoparticles Against Experimental Visceral Leishmaniasis

In the present work amphotericin B (AmB) was formulated in tristearin-based solid lipid nanoparticles (SLNs) stabilized by soya phosphatidylcholine (PC), for macrophage targeting against visceral leishmaniasis (VL). SLNs were modified by coating them with macrophage-specific ligand, O-palmitoyl mannan (OPM). The surface modified and unmodified SLNs were characterised for size, shape, zeta potential and entrapment efficiency. The antileishmanial activity of free and SLNs entrapped AmB was tested in vitro in Leishmania donovani infected macrophage-amastigote system (J774A.1 cells), which showed higher efficacy of OPM grafted AmB-SLNs (SLNs-OPM) over plain AmB-SLNs and free AmB (AmB-Doc). The in vivo organ distribution studies in albino rats confirmed that degree of accretion of SLNs entrapped AmB in macrophage rich organs, particularly liver, spleen and lungs was considerably high when compared against AmB-Doc. The rate and degree of accretion were found to increase further on ligand anchoring. The in vivo antileishmanial activity of the AmB encapsulated SLNs-OPM was found to be better as compared to SLNs and AmB-Doc against VL in L. donovani infected hamsters. The proposed formulations, SLNs and SLNs-OPM demonstrated tremendous potential for passive and active intramacrophage targeting respectively and the strategy could be a booming alternative to the presently existing drug regimens of VL and systemic fungal infections.

Development and Characterization of Amphotericin B Loaded Solid Lipid Nanoparticles Against Experimental Visceral Leishmaniasis

In the present work amphotericin B (AmB) was formulated in tristearin-based solid lipid nanoparticles (SLNs) stabilized by soya phosphatidylcholine (PC), for macrophage targeting against visceral leishmaniasis (VL). SLNs were modified by coating them with macrophage-specific ligand, O-palmitoyl mannan (OPM). The surface modified and unmodified SLNs were characterised for size, shape, zeta potential and entrapment efficiency. The antileishmanial activity of free and SLNs entrapped AmB was tested in vitro in Leishmania donovani infected macrophage-amastigote system (J774A.1 cells), which showed higher efficacy of OPM grafted AmB-SLNs (SLNs-OPM) over plain AmB-SLNs and free AmB (AmB-Doc). The in-vivo organ distribution studies in albino rats confirmed that degree of accretion of SLNs en-trapped AmB in macrophage rich organs, particularly liver, spleen and lungs was considerably high when compared against AmB-Doc. The rate and degree of accretion were found to increase further on ligand anchoring. The in vivo an-tileishmanial activity of the AmB encapsulated SLNs-OPM was found to be better as compared to SLNs and AmB-Doc against VL in L. donovani infected hamsters. The proposed formulations, SLNs and SLNs-OPM demonstrated tremendous potential for passive and active intramacrophage targeting respectively and the strategy could be a booming alternative to the presently existing drug regimens of VL and systemic fungal infections.

Characterization and Evaluation of BNIpdaoct-Loaded PLGA Nanoparticles for Visceral Leishmaniasis: In Vitro and In Vivo Studies

To overcome the limitation of bisnaphthalimidopropyldiaaminooctane (BNIPDaoct) low physiological solubility and potentially increase its efficiency against visceral leishmaniasis (VL), a delivery system based on poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles was developed. BNIPDaoct-PLGA nanoparticles were prepared by nanoprecipitation and characterized. Anti-Leishmania activity was evaluated using in vitro and in vivo VL infection models. BNIPDaoct-PLGA nanoparticles were successfully produced and were sized at 156.0 ± 2.8 nm with an encapsulation efficiency of approximately 85%. The PLGA nanoparticles reduced BNIPDaoct cellular toxicity, retained its in vitro anti-leishmanial activity and led to a significant reduction (∼80%) in the parasite burden in the infected mice spleen when compared with the free drug or amphotericin B. In the liver the effect was less pronounced, with a 30-50% reduction observed between the nanoformulation and the BNIPDaoct per se or the amphotericin B, respectively. PLGA nanoparticles provide controlled and effective delivery of BNIPDaoct for treatment of VL.