kutkin and Leishmaniasis--Visceral

Combination therapy for the treatment of visceral leishmaniasis has increasingly been advocated as a way to increase treatment efficacy and tolerance, to reduce treatment duration and cost, and to limit the emergence of drug resistance. In the present work, we have adopted a rational approach, which can modulate the immune response to overcome the negative control systems and to boost the positive killing responses. This study was designed to investigate the immunomodulatory effect of picroliv (standardized fraction from the alcoholic extract of root and rhizome of Picrorhiza kurroa) on a combination of paromomycin and miltefosine using Leishmania donovani/hamster model. Picroliv has significantly enhanced antileishmanial efficacy and lymphocyte proliferation when given in combination with paromomycin and miltefosine. Increased toxic oxygen metabolite generation and phagocytosis were also witnessed. Present study thus establishes the possible use of picroliv as adjunct to antileishmanial chemotherapy.

Topics: Animals; Antiprotozoal Agents; Cell Proliferation; Cinnamates; Cricetinae; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Therapy, Combination; Female; Glycosides; Leishmania donovani; Leishmaniasis, Visceral; Lymphocytes; Male; Mesocricetus; Paromomycin; Phagocytosis; Phosphorylcholine; Random Allocation; Reactive Nitrogen Species; Reactive Oxygen Species; Vanillic Acid

The chemotherapy of visceral leishmaniasis (VL) has several limitations including resistance and toxicity of the existing drugs. Downregulation of immune system further aggravates the problems. To combat this situation, leishmanicidal efficacy of already marketed standard antifungal drug, fluconazole under the approach of "therapeutic switching" in combination with standard antileishmanial drug, miltefosine, and a potent immunomodulator agent, picroliv, were evaluated in hamsters infected with Leishmania donovani. Animals treated with fluconazole (50 mg/kg × 5 days, oral (p.o.)) + miltefosine (5 mg/kg × 5 days, p.o.) showed enhancement in antileishmanial efficacy (77%), reactive nitrogen species, reactive oxygen species, hydrogen peroxide, and phagocytosis index as compared to those treated with individual drugs. Addition of picroliv to this combination further increased the antileishmanial efficacy from 77% to 88%. Upregulation of cell-mediated immunity was also observed in animals of this group which strengthens the immunomodulatory role of picroliv. These findings suggest a new option for antileishmanial chemotherapy at lower cost and toxicity.

Topics: Animals; Antiprotozoal Agents; Cinnamates; Cricetinae; Drug Therapy, Combination; Fluconazole; Glycosides; Hydrogen Peroxide; Immunity, Cellular; Leishmania donovani; Leishmaniasis, Visceral; Phagocytosis; Phosphorylcholine; Reactive Oxygen Species; Treatment Outcome; Vanillic Acid

Visceral leishmaniasis (VL) caused by the parasite Leishmania donovani, is a potentially fatal disease. It is characterized by prolonged fever, enlarged spleen and liver, substantial weight loss and progressive anemia. Available drugs are toxic, costly and require prolonged treatment duration viz; 28 days of oral treatment with miltefosine, 30 days infusion with Amphotericin B and 21 days intramascular with paromomycin sulfate. Drug combination for VL clinically proved to shorten the duration of treatment. The efficacy of drugs is also compromised due to suppression of immune function during the course of infection. To combat this situation leishmanicidal efficacy of already marketed standard antifungal drug, ketoconazole under the approach of 'therapeutic switching' in combination with standard antileishmanial drug, miltefosine and a potent immunomodulator agent, picroliv were evaluated in L. donovani/hamsters model. Animals treated with combination of ketoconazole (50 mg/kg, 5 days, po)+miltefosine (5 mg/kg, 5 days, po) showed augmentation in efficacy against leishmania parasite (72%) in comparison to those treated with ketoconazole (54.67%) and miltefosine (54.77%) separately. Co-administration of picroliv (10 mg/kg, 12 days, po) has further enhanced antileishmanial efficacy from 72% to 82%. Significant generation of ROS, RNS and H(2)O(2) and increased phagocytosis was observed in animals treated with ketoconazole+miltefosine; however, addition of picroliv to this combination did not alter the level of metabolites and phagocytosis due to its antioxidative and nonleishmanicidal characteristics, respectively. Significant rise in cell mediated immunity witnessed in this group reveals the role played by the immunomodulator, picroliv and justifies the significance of enhanced cell mediated immunity in the therapy. These findings suggest a new strategy for leishmanial chemotherapy at reduced cost and toxicity.

Topics: Animals; Antiprotozoal Agents; Cinnamates; Cricetinae; Disease Models, Animal; Drug Therapy, Combination; Female; Glycosides; Hydrogen Peroxide; Immunologic Factors; Ketoconazole; Leishmania donovani; Leishmaniasis, Visceral; Male; Phagocytosis; Phosphorylcholine; Reactive Nitrogen Species; Reactive Oxygen Species; Rodent Diseases; Treatment Outcome; Vanillic Acid

Visceral leishmaniasis (VL) or kala-azar continues to persist as one of the major public health problems in many tropical countries. However, no effective treatment for radical cure of the disease is yet available. Miltefosine, an alkyl phospholipid compound, is the first orally effective drug, which has shown 98% cure rate of VL patients during phase III clinical trial in India. Since this drug requires long course of treatment and has long half-life, there are fairly good chances of emergence of resistance. Furthermore, this drug has produced severe side-effects in some of the cases. We therefore examined the possibility of minimizing these effects by applying miltefosine in lower doses in combination with picrloviv, an immunomodulator against Leishmania donovani in hamsters (Mesocricetus auratus). The picroliv per se showed no antileishmanaial potential. However, when given with suboptimal dose of miltefosine, it enhanced efficacy of the latter from 45 to 86% on day 7 post treatment and from 32 to 64% on day 28 post treatment. Interestingly, the efficacy of this combination was as good as the curative dose of miltefosine alone. Thus, this combination appears to offer a fruitful strategy for treatment of VL.

Topics: Adjuvants, Immunologic; Animals; Antiprotozoal Agents; Biopsy; Cinnamates; Cricetinae; Drug Interactions; Drug Therapy, Combination; Female; Glycosides; Leishmania donovani; Leishmaniasis, Visceral; Male; Mesocricetus; Parasitemia; Phosphorylcholine; Picrorhiza; Vanillic Acid

The prevalent drugs for treatment of kala azar viz. sodium stibogluconate (SSG) and pentamidine cause severe toxic side effects and acute immunosuppression in the treated individuals. Picroliv, a standardized mixture of iridoid glycosides, prepared from the alcoholic extract of the root and rhizome of Picrorhiza kurroa has shown strong hepatoprotective activity against several models of hepatotoxicity. Therefore, the present study was undertaken with an objective to study the effects of Picroliv (12.5 mg/kg x 7 days oral) alone and in combination with SSG on parasitemia, lipid peroxidation and hepatic marker enzymes of golden hamsters during Leishmania donovani infection. The results indicated a marked hepatoprotective effect of Picroliv in terms of biochemical markers, and a significant antileishmanial activity implying that it can be utilized as an adjunct to chemotherapy or in combination therapy of kala azar along with sodium stibogluconate, thus enhancing the efficacy of antileishmanials.

Topics: Administration, Oral; Animals; Antimony Sodium Gluconate; Antiprotozoal Agents; Bilirubin; Cinnamates; Cricetinae; Drug Therapy, Combination; Glucose-6-Phosphatase; Glutamate Synthase; Glycosides; Leishmania donovani; Leishmaniasis, Visceral; Lipid Peroxidation; Liver; Mesocricetus; Plant Extracts; Succinate Dehydrogenase; Vanillic Acid

Picroliv, a standardised fraction from root and rhizome of Picrorhiza kurroa, consisting of iridoid glycosides and shown to be responsible for its hepatoprotective activity, was studied for immunostimulant activity. Oral administration of Picroliv (10 mg/kg x 7 days) in mice prior to immunization with sheep red blood cells (SRBC) resulted in a significant increase in haemagglutinating antibody (HA) titre, plaque forming cells (PFC), and delayed hypersensitivity (DTH) response to SRBC. Picroliv enhanced the non-specific immune response characterized by an increase in macrophage migration index (MMI), [14C]-glucosamine uptake, phagocytosis of [14C]-leucine labelled Escherichia coli, chemiluminescence of peritoneal macrophages, and higher uptake of [3H]-thymidine in the lymphocytes of treated mice. It also induced a high degree of protection in golden hamsters against challenge infection with Leishmania donovani promastigotes.

Topics: Adjuvants, Immunologic; Animals; Antigens, Protozoan; Cinnamates; Cricetinae; Female; Glycosides; Leishmania donovani; Leishmaniasis, Visceral; Male; Mesocricetus; Mice; Mice, Inbred BALB C; Plants, Medicinal; Vanillic Acid