In Vitro Anti-Leishmanial Effect of Metallic Meso-Substituted Porphyrin Derivatives against Leishmania braziliensis and Leishmania panamensis Promastigotes Properties.

In this study, a family of porphyrins based on 5,10,15,20-Tetrakis(4-ethylphenyl)porphyrin (1, Ph) and six metallo-derivatives (Zn2+(2, Ph-Zn), Sn4+(3, Ph-Sn), Mn2+ (4, Ph-Mn), Ni2+ (5, Ph-Ni), Al3+ (6, Ph-Al), and V3+ (7, Ph-V)) were tested as photosensitizers for photodynamic therapy against Leishmania braziliensis and panamensis. The singlet oxygen quantum yield value (ΦΔ) for (1-7) was measured using 1,3-diphenylisobenzofuran (DPBF) as a singlet oxygen trapping agent and 5,10,15,20-(tetraphenyl)-porphyrin (H2TPP) as a reference standard; besides, parasite viability was estimated by the MTT assay. After metal insertion into the porphyrin core, the ΦΔ increased from 0.76-0.90 and cell viability changed considerably. The ΦΔ and metal type changed the cytotoxic activity. Finally, (2) showed both the highest ΦΔ (0.90) and the best photodynamic activity against the parasites studied (IC50 of 1.2 µM).

Solution-combustion synthesis of doped TiO2 compounds and its potential antileishmanial activity mediated by photodynamic therapy.

Photodynamic therapy has emerged as an alternative treatment for cutaneous leishmaniasis, and compounds with photocatalytic behavior are promising candidates to develop new therapeutic strategies for the treatment of this parasitic disease. Titanium dioxide TiO2 is a semiconductor ceramic material that shows excellent photocatalytic and antimicrobial activity under Ultraviolet irradiation. Due to the harmful effects of UV radiation, many efforts have been made in order to enhance both photocatalytic and antimicrobial properties of TiO2 in the visible region of the spectrum by doping or through modifications in the route of synthesis. Herein, Fe-, Zn-, or Pt- doped TiO2 nanostructures were synthesized by solution-combustion route. The obtained compounds presented aggregates of 100 nm, formed by particles smaller than 20 nm. Doping compounds shift the absorption spectrum towards the visible region, allowing production of reactive oxygen species in the presence of oxygen and molecular water when the system is irradiated in the visible spectrum. The Pt (EC50 = 18.2 ±â€¯0.8 µg/mL) and Zn (EC50 = 16.4 ±â€¯0.3 µg/mL) -doped TiO2 presented the higher antileishmanial activities under visible irradiation and their application as photosensitizers in photodynamic therapy (PDT) strategies for the treatment of cutaneous leishmaniasis should be considered.

Safety and efficacy of current alternatives in the topical treatment of cutaneous leishmaniasis: a systematic review.

Studies of topical treatments for leishmaniasis were systematically reviewed, to evaluate the therapeutic efficacy, safety and any adverse effects of these treatments. The papers identified in the databases PubMed and Web of Knowledge involved eight studies with a total of 1744 patients. The majority of trials was from Iran (4/8), covered a period of 8 years (2003-2011), and included patients 4-85 years of age. The most frequent Leishmania species in the studies were L. tropica (4/8) and L. major (2/8). The treatments administered were thermotherapy, paromomycin and combinations, CO2 laser, 5-aminolevulinic acid hydrochloride (10%) plus visible red light (633 nm) and cryotherapy. Six articles reported cure rates over 80·0%. Six studies reported on failure rates, three of them reporting rates lower than 10%. Four studies did not report relapses or recurrences, while the other studies reported low rates (1·8-6·3%). The most common adverse effects of the topical treatments were redness/erythema, pain, pruritus burning, oedema, vesicles and hyper- or hypopigmentation. The results provide strong evidence that the treatments topical evaluated showed high cure rates, safety and effectiveness, with low side-effects, relapse and recurrence rates, except for cryotherapy, which showed a moderate cure rate.

Acción del luz UV y riboflavina en inactivación da Leishmania en sangre canino mantenido en bolsas de transfusión / Action of ultraviolet light and riboflavin in the inactivation of Leishmania in canine blood stored in bags for transfusion / Ação da luz ultravioleta e da riboflavina na inativação de Leishmania em sangue canino conservado em bolsas para transfusão

Es extremadamente importante para la medicina de transfusión tener seguridad en procedimiento de transferencia de componentes de la sangre, lo que minimiza la aparición de transmisión de patógenos. Este estudio investigó la eficacia de la luz ultravioleta y riboflavina en la inactivación de Leishmania infantum chagasi en muestras de sangre de perros recogidos en bolsas de plástico para la transfusión. Para detectar bolsas de sangre positivos para ser utilizado en el experimento se realizó PCR convencionales de las bolsas tomadas de animales sintomáticos, la aspiración positiva de los ganglios linfáticos y IFA (título de 1: 640) a partir de CCZ Araçatuba-SP. Después de 21 días de almacenamiento a 4C la sangre canina parasitada se añadió a riboflavina a una concentración final de 50µM. A partir de entonces, la bolsa fue colocada en el iluminador a una longitud de onda de 365 nm de luz UV durante 30 a 45 minutos y se mantuvo sobre uno homogeneizador de bolsa de sangre. Para demostrar la inactivación se usaron 28 hámsteres (Mesocricetus auratus), machos, adultos. Siete animales fueron inoculados con la sangre sin tratamiento (grupo de leishmaniasis: GL); siete de sangre después de la adición de riboflavina (grupo de riboflavina: GRB); siete de sangre después del tratamiento con riboflavina asociada con luz ultravioleta durante 30 minutos (grupo tratado 1: GT30) y siete con la [...]

It is extremely important for the transfusion medicine the safety in blood components transfer procedure, minimizing the occurrence of pathogen transmission. This study investigated the efficiency of ultraviolet light and riboflavin in the inactivation of Leishmania infantum chagasi in canine blood samples collected in plastic bags for transfusion. To detect positive blood bags to be used in the experiment, it was performed conventional PCR of the bags collected from symptomatic animals, with positive aspiration of lymph node and IFA (title 1: 640), from an epidemic region for the disease. After 21 days of storage at 4C, parasitized canine blood riboflavin was added to a final concentration of 50M. Thereafter, the bag was placed in the illuminator at a wavelength of 365 nm UV light for 30 to 45 minutes and maintained over a homogenizer blood bag. To prove the inactivation, they were used 28 hamsters (Mesocricetus auratus), adult, male. Seven animals were inoculated with the blood without treatment (group leishmaniasis: GL); seven, with blood after the addition of riboflavin (riboflavin group: GRB); seven, with blood after treatment with riboflavin associated with ultraviolet light for 30 minutes (treated group 1: GT30) and seven, with blood after treatment with riboflavin associated with ultraviolet light for 45 minutes (treated group 2: GT45). The animals were kept [...]

É de extrema importância para a medicina transfusional que haja segurança no procedimento de transferência de hemocomponentes, minimizando a ocorrência da transmissão de patógenos. O presente trabalho investigou a eficiência da luz ultravioleta e riboflavina na inativação de Leishmania infantum chagasi em amostras de sangue canino, colhidas em bolsas plásticas para transfusão. Para detectar as bolsas de sangue positivas a serem utilizadas no experimento, foi realizada PCR convencional de sangue de bolsas colhidas de animais sintomáticos, positivos na punção aspirativa de linfonodo e na RIFI (título 1:640), procedentes do CCZ de região epidêmica para a enfermidade. Após 21 dias de armazenamento em temperatura de 4ºC, o sangue canino parasitado foi adicionado de riboflavina na concentração final de 50µM. Posteriormente, a bolsa foi colocada no iluminador a um comprimento de onda de 365 nm de luz UV por 30 e 45 minutos, sendo mantida sobre um homogeinizador de bolsa de sangue. Para comprovar a inativação, foram utilizados 28 hamsters (Mesocricetus auratus), machos e adultos. Sete animais foram inoculados com o sangue sem tratamento (grupo leishmaniose: GL); sete, com sangue após a adição de riboflavina (grupo riboflavina: GRB); sete, com sangue após tratamento com riboflavina associado à luz ultravioleta por 30 minutos (grupo tratado 1: GT30) e sete, com sangue após tratamento [...]

Acción del luz UV y riboflavina en inactivación da Leishmania en sangre canino mantenido en bolsas de transfusión / Action of ultraviolet light and riboflavin in the inactivation of Leishmania in canine blood stored in bags for transfusion / Ação da luz ultravioleta e da riboflavina na inativação de Leishmania em sangue canino conservado em bolsas para transfusão

Es extremadamente importante para la medicina de transfusión tener seguridad en procedimiento de transferencia de componentes de la sangre, lo que minimiza la aparición de transmisión de patógenos. Este estudio investigó la eficacia de la luz ultravioleta y riboflavina en la inactivación de Leishmania infantum chagasi en muestras de sangre de perros recogidos en bolsas de plástico para la transfusión. Para detectar bolsas de sangre positivos para ser utilizado en el experimento se realizó PCR convencionales de las bolsas tomadas de animales sintomáticos, la aspiración positiva de los ganglios linfáticos y IFA (título de 1: 640) a partir de CCZ Araçatuba-SP. Después de 21 días de almacenamiento a 4C la sangre canina parasitada se añadió a riboflavina a una concentración final de 50µM. A partir de entonces, la bolsa fue colocada en el iluminador a una longitud de onda de 365 nm de luz UV durante 30 a 45 minutos y se mantuvo sobre uno homogeneizador de bolsa de sangre. Para demostrar la inactivación se usaron 28 hámsteres (Mesocricetus auratus), machos, adultos. Siete animales fueron inoculados con la sangre sin tratamiento (grupo de leishmaniasis: GL); siete de sangre después de la adición de riboflavina (grupo de riboflavina: GRB); siete de sangre después del tratamiento con riboflavina asociada con luz ultravioleta durante 30 minutos (grupo tratado 1: GT30) y siete con la [...](AU)

It is extremely important for the transfusion medicine the safety in blood components transfer procedure, minimizing the occurrence of pathogen transmission. This study investigated the efficiency of ultraviolet light and riboflavin in the inactivation of Leishmania infantum chagasi in canine blood samples collected in plastic bags for transfusion. To detect positive blood bags to be used in the experiment, it was performed conventional PCR of the bags collected from symptomatic animals, with positive aspiration of lymph node and IFA (title 1: 640), from an epidemic region for the disease. After 21 days of storage at 4C, parasitized canine blood riboflavin was added to a final concentration of 50M. Thereafter, the bag was placed in the illuminator at a wavelength of 365 nm UV light for 30 to 45 minutes and maintained over a homogenizer blood bag. To prove the inactivation, they were used 28 hamsters (Mesocricetus auratus), adult, male. Seven animals were inoculated with the blood without treatment (group leishmaniasis: GL); seven, with blood after the addition of riboflavin (riboflavin group: GRB); seven, with blood after treatment with riboflavin associated with ultraviolet light for 30 minutes (treated group 1: GT30) and seven, with blood after treatment with riboflavin associated with ultraviolet light for 45 minutes (treated group 2: GT45). The animals were kept [...](AU)

É de extrema importância para a medicina transfusional que haja segurança no procedimento de transferência de hemocomponentes, minimizando a ocorrência da transmissão de patógenos. O presente trabalho investigou a eficiência da luz ultravioleta e riboflavina na inativação de Leishmania infantum chagasi em amostras de sangue canino, colhidas em bolsas plásticas para transfusão. Para detectar as bolsas de sangue positivas a serem utilizadas no experimento, foi realizada PCR convencional de sangue de bolsas colhidas de animais sintomáticos, positivos na punção aspirativa de linfonodo e na RIFI (título 1:640), procedentes do CCZ de região epidêmica para a enfermidade. Após 21 dias de armazenamento em temperatura de 4ºC, o sangue canino parasitado foi adicionado de riboflavina na concentração final de 50µM. Posteriormente, a bolsa foi colocada no iluminador a um comprimento de onda de 365 nm de luz UV por 30 e 45 minutos, sendo mantida sobre um homogeinizador de bolsa de sangue. Para comprovar a inativação, foram utilizados 28 hamsters (Mesocricetus auratus), machos e adultos. Sete animais foram inoculados com o sangue sem tratamento (grupo leishmaniose: GL); sete, com sangue após a adição de riboflavina (grupo riboflavina: GRB); sete, com sangue após tratamento com riboflavina associado à luz ultravioleta por 30 minutos (grupo tratado 1: GT30) e sete, com sangue após tratamento [...](AU)

Chlorin E6 phototoxicity in L. major and L. braziliensis promastigotes-In vitro study.

BACKGROUND: Cutaneous leishmaniasis is a zoonosis caused by protozoa of the genus Leishmania. Conventional treatments are long and aggressive, and they trigger a diversity of side effects. Photodynamic Therapy was originally proposed as a treatment for cancer, and it now appears to be a promising therapy for local treatment with fewer side effects of infectious diseases. METHODS: This study aimed to evaluate Chlorin e6 internalization by Leishmania major and Leishmania braziliensis promastigotes and its viability and effects on mitochondrial activity. Control groups were kept in the dark, while PDT groups received fluence of 10J/cm(2) (660nm). Chlorin internalization was evaluated using confocal microscopy after one hour of incubation for both species. RESULTS: The mitochondrial activity was evaluated by MTT assay, and viability was measured by the Trypan blue exclusion test. Giemsa staining was used to observe morphological changes. PS was internalized in both species and mitochondrial activity changed in all groups. However, the obtained MTT and Trypan results indicated that despite the change in mitochondrial activity in the dark groups, their viability was not affected, whereas the PDT treated groups had significantly reduced viability. Morphology was drastically altered in PDT treated groups, while groups kept in the dark exhibited the standard morphology. CONCLUSIONS: This study demonstrates that Chlorin has great potential for being used in PDT as a treatment for cutaneous leishmaniasis, although more studies are needed to determine in vivo application protocols.

Enhanced photodynamic leishmanicidal activity of hydrophobic zinc phthalocyanine within archaeolipids containing liposomes.

In this work, the in vitro anti-Leishmania activity of photodynamic liposomes made of soybean phosphatidylcholine, sodium cholate, total polar archaeolipids (TPAs) extracted from the hyperhalophile archaea Halorubrum tebenquichense and the photosensitizer zinc phthalocyanine (ZnPcAL) was compared to that of ultradeformable photodynamic liposomes lacking TPAs (ZnPcUDLs). We found that while ZnPcUDLs and ZnPcALs (130 nm mean diameter and -35 mV zeta potential) were innocuous against promastigotes, a low concentration (0.01 µM ZnPc and 7.6 µM phospholipids) of ZnPcALs irradiated at a very low-energy density (0.2 J/cm(2)) eliminated L. braziliensis amastigotes from J774 macrophages, without reducing the viability of the host cells. In such conditions, ZnPcALs were harmless for J774 macrophages, HaCaT keratinocytes, and bone marrow-derived dendritic cells. Therefore, topical photodynamic treatment would not likely affect skin-associated lymphoid tissue. ZnPcALs were extensively captured by macrophages, but ZnPcUDLs were not, leading to 2.5-fold increased intracellular delivery of ZnPc than with ZnPcUDLs. Despite mediating low levels of reactive oxygen species, the higher delivery of ZnPc and the multiple (caveolin- and clathrin-dependent plus phagocytic) intracellular pathway followed by ZnPc would have been the reason for the higher antiamastigote activity of ZnPcALs. The leishmanicidal activity of photodynamic liposomal ZnPc was improved by TPA-containing liposomes.

In vitro phototoxicity of ultradeformable liposomes containing chloroaluminum phthalocyanine against New World Leishmania species.

The use of photodynamic therapy (PDT) against cutaneous leishmaniasis (CL) based on chloroaluminum phthalocyanine (ClAlPc) is a promissory alternative therapy. The main purpose of this article was to assess the internalization and in vitro phototoxic activities of ClAlPc encapsulated in ultradeformable liposomes (UDL-ClAlPc) in Leishmania parasites and mammalian cells. Cell internalization was determined by fluorescence microscopy, cell and parasite damage by standard MTT or direct microscopic analysis and a phototoxic index (PI) was calculated as the compound activity (IC(50)) at 0 J/cm(2)/IC(50) at 17 J/cm(2). Liposomal and free ClAlPc were internalized by infected and non-infected THP-1 cells and co-localized in the mitochondria. Treatment of UDL-ClAlPc was almost 10 times more photoactive than free ClAlPc on THP-1 cells and promastigotes and intracellular amastigotes of Leishmania chagasi and Leishmania panamensis. Liposomal compounds were active on non-irradiated and irradiated cells however PI higher than 50 were calculated. PI for amphotericin B referential drug were lower than 1.2. Empty liposomes tested at the same lipid concentration of active ClPcAl-liposomes were non-toxic. Upon photodynamic treatment a nonselective-parasite activity against intracellular amastigotes were observed and loss of membrane integrity resulting in a release of parasites was detected. Further studies oriented to evaluate both the state of infection after PDT and the effectiveness of UDL as delivery vehicles of ClAlPc in CL experimental models are required.

A radioattenuated Leishmania major vaccine markedly increases the resistance of CBA mice to subsequent infection with Leishmania mexicana mexicana.

Vaccinating CBA mice with radioattenuated Leishmania major amastigotes but not with radioattenuated L. mexicana mexicana amastigotes rendered them highly resistant to subsequent infection with L. m. mexicana. Unvaccinated CBA mice were highly susceptible to infection with L. m. mexicana producing rapidly growing non-ulcerating cutaneous lesions. Two manifestations of resistance were induced in vaccinated animals depending on the timing of the challenge infection: no lesions appeared at the site of subcutaneous challenge in animals vaccinated four or more weeks previously, while lesions grew rapidly but ulcerated and healed in animals vaccinated less than 3 weeks beforehand. L. major amastigotes were found to be markedly more resistant to gamma irradiation than L. m. mexicana amastigotes both as measured by their ability to infect susceptible strains of mice and to transform and multiply as promastigotes in NNN medium.