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Association of liposome-encapsulated trivalent antimonial with ascorbic acid: an effective and safe strategy in the treatment of experimental visceral leishmaniasis.

Castro RA, Silva-Barcellos NM, Licio CS, Souza JB, Souza-Testasicca MC, Ferreira FM, Batista MA, Silveira-Lemos D, Moura SL, Frézard F, Rezende SA - PLoS ONE (2014)

Bottom Line: Considering the lack of an effective vaccine the afflicted population must rely on both, an accurate diagnosis and successful treatment to combat the disease.Treatment with liposome-encapsulated SbIII significantly reduced the parasite burden in the liver, spleen and bone marrow.Of particular importance, reduction of parasite burden in the bone marrow attested to the ability of SbIII-carrying liposomes to efficiently reach this body compartment.

View Article: PubMed Central - PubMed

Affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas - Cipharma, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil.

ABSTRACT

Background: Visceral leishmaniasis (VL) is a chronic debilitating disease endemic in tropical and subtropical areas, caused by protozoan parasites of the genus Leishmania. Annually, it is estimated the occurrence of 0.2 to 0.4 million new cases of the disease worldwide. Considering the lack of an effective vaccine the afflicted population must rely on both, an accurate diagnosis and successful treatment to combat the disease. Here we propose to evaluate the efficacy of trivalent antimonial encapsulated in conventional liposomes, in association with ascorbic acid, by monitoring its toxicity and efficacy in BALB/c mice infected with Leishmania infantum.

Methodology/principal findings: Infected mice were subjected to single-dose treatments consisting in the administration of either free or liposome-encapsulated trivalent antimony (SbIII), in association or not with ascorbic acid. Parasite burden was assessed in the liver, spleen and bone marrow using the serial limiting dilution technique. After treatment, tissue alterations were examined by histopathology of liver, heart and kidney and confirmed by serum levels of classic biomarkers. The phenotypic profile of splenocytes was also investigated by flow cytometry. Treatment with liposome-encapsulated SbIII significantly reduced the parasite burden in the liver, spleen and bone marrow. Co-administration of ascorbic acid, with either free SbIII or its liposomal form, did not interfere with its leishmanicidal activity and promoted reduced toxicity particularly to the kidney and liver tissues.

Conclusions/significance: Among the evaluated posological regimens treatment of L. infantum-infected mice with liposomal SbIII, in association with ascorbic acid, represented the best alternative as judged by its high leishmanicidal activity and absence of detectable toxic effects. Of particular importance, reduction of parasite burden in the bone marrow attested to the ability of SbIII-carrying liposomes to efficiently reach this body compartment.

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Histopathological analyses of the liver from L. infantum infected mice submitted to different treatment regimens.(A) Phosphate-buffered saline (PBS). (B) Empty liposomes (Empty Lipo). (C) Trivalent antimony (Sb). (D) Antimony entrapped liposomes (Sb Lipo). (E) Ascorbic acid (AA). (F) Ascorbic acid in association with antimony (AA+Sb). (G) Ascorbic acid in association with antimony entrapped liposomes (AA+Sb Lipo). Bar  = 50 µm. Insert  = 25 µm, representing an immature granuloma. Dashed arrow  =  Inflammatory cell foci. Arrowhead  =  Kupffer cells exhibiting hypertrophy. * Hyperemic vessels.
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pone-0104055-g003: Histopathological analyses of the liver from L. infantum infected mice submitted to different treatment regimens.(A) Phosphate-buffered saline (PBS). (B) Empty liposomes (Empty Lipo). (C) Trivalent antimony (Sb). (D) Antimony entrapped liposomes (Sb Lipo). (E) Ascorbic acid (AA). (F) Ascorbic acid in association with antimony (AA+Sb). (G) Ascorbic acid in association with antimony entrapped liposomes (AA+Sb Lipo). Bar  = 50 µm. Insert  = 25 µm, representing an immature granuloma. Dashed arrow  =  Inflammatory cell foci. Arrowhead  =  Kupffer cells exhibiting hypertrophy. * Hyperemic vessels.

Mentions: Histopathological analyses of the hepatic tissue demonstrated that infected animals treated with PBS, empty liposomes, free SbIII, AA and AA + Sb exhibited a typical granulomatous inflammation (Figures 3A–C). Quantitative analyses of the tissue area occupied by granulomatous inflammation, in animals belonging to the aforementioned groups, statistically confirmed such finding (Figure 4). In particular, the cell exudate was mainly composed of macrophages and epithelioid cells organized in immature granulomas (Figure 3C, insert). Intralobular focal infiltrates of lymphoplasmocytes were also observed (Figures 3A and 3B, dashed arrows). A diffuse increase in the number of Kupffer cells within the sinusoidal spaces was noted, with the cells exhibiting hypertrophy (Figure 3B, arrowhead). Some centrolobular hepatocytes displayed a moderate degree of hydropic degeneration. The centrolobular veins and the hepatic vein branches, at the portal spaces, were highly hyperemic containing a moderate mononuclear infiltrate as a perivasculitis (Figure 3C, 3E, asterisked areas). For animals treated with liposomal SbIII in association or not with ascorbic acid, hepatic granulomas were not observed. More effectively, the combination of liposomal SbIII with ascorbic acid resulted in pronounced reductions in the inflammatory infiltrate and associated hyperemia when compared to treatment with liposomal SbIII only. Actually, animals treated with the liposomal SbIII/ascorbic acid combination exhibited, at the most, a discrete hyperemia with no alterations on the morphology of Kupffer cells at the sinusoidal spaces (Figure 3G).


Association of liposome-encapsulated trivalent antimonial with ascorbic acid: an effective and safe strategy in the treatment of experimental visceral leishmaniasis.

Castro RA, Silva-Barcellos NM, Licio CS, Souza JB, Souza-Testasicca MC, Ferreira FM, Batista MA, Silveira-Lemos D, Moura SL, Frézard F, Rezende SA - PLoS ONE (2014)

Histopathological analyses of the liver from L. infantum infected mice submitted to different treatment regimens.(A) Phosphate-buffered saline (PBS). (B) Empty liposomes (Empty Lipo). (C) Trivalent antimony (Sb). (D) Antimony entrapped liposomes (Sb Lipo). (E) Ascorbic acid (AA). (F) Ascorbic acid in association with antimony (AA+Sb). (G) Ascorbic acid in association with antimony entrapped liposomes (AA+Sb Lipo). Bar  = 50 µm. Insert  = 25 µm, representing an immature granuloma. Dashed arrow  =  Inflammatory cell foci. Arrowhead  =  Kupffer cells exhibiting hypertrophy. * Hyperemic vessels.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126701&req=5

pone-0104055-g003: Histopathological analyses of the liver from L. infantum infected mice submitted to different treatment regimens.(A) Phosphate-buffered saline (PBS). (B) Empty liposomes (Empty Lipo). (C) Trivalent antimony (Sb). (D) Antimony entrapped liposomes (Sb Lipo). (E) Ascorbic acid (AA). (F) Ascorbic acid in association with antimony (AA+Sb). (G) Ascorbic acid in association with antimony entrapped liposomes (AA+Sb Lipo). Bar  = 50 µm. Insert  = 25 µm, representing an immature granuloma. Dashed arrow  =  Inflammatory cell foci. Arrowhead  =  Kupffer cells exhibiting hypertrophy. * Hyperemic vessels.
Mentions: Histopathological analyses of the hepatic tissue demonstrated that infected animals treated with PBS, empty liposomes, free SbIII, AA and AA + Sb exhibited a typical granulomatous inflammation (Figures 3A–C). Quantitative analyses of the tissue area occupied by granulomatous inflammation, in animals belonging to the aforementioned groups, statistically confirmed such finding (Figure 4). In particular, the cell exudate was mainly composed of macrophages and epithelioid cells organized in immature granulomas (Figure 3C, insert). Intralobular focal infiltrates of lymphoplasmocytes were also observed (Figures 3A and 3B, dashed arrows). A diffuse increase in the number of Kupffer cells within the sinusoidal spaces was noted, with the cells exhibiting hypertrophy (Figure 3B, arrowhead). Some centrolobular hepatocytes displayed a moderate degree of hydropic degeneration. The centrolobular veins and the hepatic vein branches, at the portal spaces, were highly hyperemic containing a moderate mononuclear infiltrate as a perivasculitis (Figure 3C, 3E, asterisked areas). For animals treated with liposomal SbIII in association or not with ascorbic acid, hepatic granulomas were not observed. More effectively, the combination of liposomal SbIII with ascorbic acid resulted in pronounced reductions in the inflammatory infiltrate and associated hyperemia when compared to treatment with liposomal SbIII only. Actually, animals treated with the liposomal SbIII/ascorbic acid combination exhibited, at the most, a discrete hyperemia with no alterations on the morphology of Kupffer cells at the sinusoidal spaces (Figure 3G).

Bottom Line: Considering the lack of an effective vaccine the afflicted population must rely on both, an accurate diagnosis and successful treatment to combat the disease.Treatment with liposome-encapsulated SbIII significantly reduced the parasite burden in the liver, spleen and bone marrow.Of particular importance, reduction of parasite burden in the bone marrow attested to the ability of SbIII-carrying liposomes to efficiently reach this body compartment.

View Article: PubMed Central - PubMed

Affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas - Cipharma, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil.

ABSTRACT

Background: Visceral leishmaniasis (VL) is a chronic debilitating disease endemic in tropical and subtropical areas, caused by protozoan parasites of the genus Leishmania. Annually, it is estimated the occurrence of 0.2 to 0.4 million new cases of the disease worldwide. Considering the lack of an effective vaccine the afflicted population must rely on both, an accurate diagnosis and successful treatment to combat the disease. Here we propose to evaluate the efficacy of trivalent antimonial encapsulated in conventional liposomes, in association with ascorbic acid, by monitoring its toxicity and efficacy in BALB/c mice infected with Leishmania infantum.

Methodology/principal findings: Infected mice were subjected to single-dose treatments consisting in the administration of either free or liposome-encapsulated trivalent antimony (SbIII), in association or not with ascorbic acid. Parasite burden was assessed in the liver, spleen and bone marrow using the serial limiting dilution technique. After treatment, tissue alterations were examined by histopathology of liver, heart and kidney and confirmed by serum levels of classic biomarkers. The phenotypic profile of splenocytes was also investigated by flow cytometry. Treatment with liposome-encapsulated SbIII significantly reduced the parasite burden in the liver, spleen and bone marrow. Co-administration of ascorbic acid, with either free SbIII or its liposomal form, did not interfere with its leishmanicidal activity and promoted reduced toxicity particularly to the kidney and liver tissues.

Conclusions/significance: Among the evaluated posological regimens treatment of L. infantum-infected mice with liposomal SbIII, in association with ascorbic acid, represented the best alternative as judged by its high leishmanicidal activity and absence of detectable toxic effects. Of particular importance, reduction of parasite burden in the bone marrow attested to the ability of SbIII-carrying liposomes to efficiently reach this body compartment.

Show MeSH
Related in: MedlinePlus