Correlation between clinical efficacy on pruritus and serum interleukin-31 levels in dogs with atopic dermatitis treated with lokivetmab.

Studies on serum interleukin (IL)-31 levels in dogs with atopic dermatitis (AD) and their correlation with disease severity are limited. To the author's knowledge, there are no studies that measured serum IL-31 in dogs treated with lokivetmab injections, a selective inhibitor of this key cytokine in pruritus. The aim of the study was to evaluate serum IL-31 levels in dogs treated with lokivetmab and correlate it with the severity of canine atopic dermatitis using the pruritus visual analog scale (pVAS) and canine atopic dermatitis extent and severity index (CADESI-04). Ten client-owned dogs diagnosed with AD received two injections of lokivetmab four weeks apart. Disease severity was assessed using the pVAS and CADESI-04 scores before and after both injections. In addition, canine serum IL-31 levels were measured at the same moments. Serum IL-31 was detected in all dogs in the study. There was a significant reduction in pVAS scores and serum IL-31 after administrations. However, there was no difference in CADESI-04 scores, and there was no significant correlation between CADESI-04 scores and serum IL-31 in dogs diagnosed with AD. Nonetheless, a significant positive correlation was observed between the pVAS scores and serum IL-31 levels with lokivetmab therapy, which reinforces the role of IL-31 in the pathogenesis of pruritus in dogs with AD. The data presented here provide further evidence that IL-31 is directly involved in pruritus pathogenesis in dogs with AD. In addition, blocking IL-31 has a significant antipruritic effect, but has no influence on skin lesion severity and extension.

Humoral immunological profile and parasitological statuses of Leishmune vaccinated and visceral leishmaniasis infected dogs from an endemic area.

Dogs represent the major reservoir of Leishmaniao chagasi and vaccination against the canine disease is a potential control strategy. However, seroconversion occurs post-vaccine and hence, there is need to discriminate between the former group and naturally infected dogs. The present study represents a comparison of the humoral immunological profiles of both groups using Leishmania soluble antigen (LSA) and fucose-mannose ligand (FML). For both categories, ear skin samples were evaluated immunohistochemically and through PCR, that was also performed in blood specimens, as well as their ability to infect Lutzomyia (Lutzomyia) longipalpis. All these tests showed negative results for the vaccinated dogs. Differences between groups were observed regarding IgG, IgG2 and IgE absorbances as determined by FML-ELISA, and for IgG1 and IgE absorbances as measured by LSA-ELISA, showing that Leishmune-immunised animals and VL naturally infected dogs present different immunological profiles, even though these differences cannot be used to distinguish between these two groups of dogs.

Pharmacokinetic and parasitological evaluation of the bone marrow of dogs with visceral leishmaniasis submitted to multiple dose treatment with liposome-encapsulated meglumine antimoniate

The aim of the present study was to evaluate the impact of a multiple dose regimen of a liposomal formulation of meglumine antimoniate (LMA) on the pharmacokinetics of antimony in the bone marrow of dogs with visceral leishmaniasis and on the ability of LMA to eliminate parasites from this tissue. Dogs naturally infected with Leishmania chagasi received 4 intravenous doses of either LMA (6.5 mg antimony/kg body weight, N = 9), or empty liposomes (at the same lipid dose as LMA, N = 9) at 4-day intervals. A third group of animals was untreated (N = 8). Before each administration and at different times after treatment, bone marrow was obtained and analyzed for antimony level (LMA group) by electrothermal atomic absorption spectrometry, and for the presence of Leishmania parasites (all groups). There was a significant increase of antimony concentration from 0.76 æg/kg wet organ (4 days after the first dose) to 2.07 æg/kg (4 days after the fourth dose) and a half-life of 4 days for antimony elimination from the bone marrow. Treatment with LMA significantly reduced the number of dogs positive for parasites (with at least one amastigote per 1000 host cells) compared to controls (positive dogs 30 days after treatment: 0 of 9 in the LMA group, 3 of 9 in the group treated with empty liposomes and 3 of 8 in the untreated group). However, complete elimination of parasites was not achieved. In conclusion, the present study showed that multiple dose treatment with LMA was effective in improving antimony levels in the bone marrow of dogs with visceral leishmaniasis and in reducing the number of positive animals, even though it was not sufficient to achieve complete elimination of parasites.

Pharmacokinetic and parasitological evaluation of the bone marrow of dogs with visceral leishmaniasis submitted to multiple dose treatment with liposome-encapsulated meglumine antimoniate.

The aim of the present study was to evaluate the impact of a multiple dose regimen of a liposomal formulation of meglumine antimoniate (LMA) on the pharmacokinetics of antimony in the bone marrow of dogs with visceral leishmaniasis and on the ability of LMA to eliminate parasites from this tissue. Dogs naturally infected with Leishmania chagasi received 4 intravenous doses of either LMA (6.5 mg antimony/kg body weight, N = 9), or empty liposomes (at the same lipid dose as LMA, N = 9) at 4-day intervals. A third group of animals was untreated (N = 8). Before each administration and at different times after treatment, bone marrow was obtained and analyzed for antimony level (LMA group) by electrothermal atomic absorption spectrometry, and for the presence of Leishmania parasites (all groups). There was a significant increase of antimony concentration from 0.76 microg/kg wet organ (4 days after the first dose) to 2.07 microg/kg (4 days after the fourth dose) and a half-life of 4 days for antimony elimination from the bone marrow. Treatment with LMA significantly reduced the number of dogs positive for parasites (with at least one amastigote per 1000 host cells) compared to controls (positive dogs 30 days after treatment: 0 of 9 in the LMA group, 3 of 9 in the group treated with empty liposomes and 3 of 8 in the untreated group). However, complete elimination of parasites was not achieved. In conclusion, the present study showed that multiple dose treatment with LMA was effective in improving antimony levels in the bone marrow of dogs with visceral leishmaniasis and in reducing the number of positive animals, even though it was not sufficient to achieve complete elimination of parasites.

Distribution of liposome-encapsulated antimony in dogs.

The achievement of complete cure in dogs with visceral leishmaniasis is currently a great challenge, since dogs are the main reservoir for the transmission of visceral leishmaniasis to humans and they respond poorly to conventional treatment with pentavalent antimonials. In order to improve the efficacy of treatment, we developed a novel formulation for meglumine antimoniate based on the encapsulation of this drug in freeze-dried liposomes (LMA). The aim of the present study was to evaluate the biodistribution of antimony (Sb) in dogs following a single intravenous bolus injection of LMA. Four healthy male mongrel dogs received LMA at 3.8 mg Sb/kg body weight and were sacrificed 3, 48 and 96 h and 7 days later. Antimony was determined in the blood, liver, spleen and bone marrow. In the bone marrow, the highest Sb concentration was observed at 3 h (2.8 microg/g wet weight) whereas in the liver and spleen it was demonstrated at 48 h (43.6 and 102.4 microg/g, respectively). In these organs, Sb concentrations decreased gradually and reached levels of 19.1 microg/g (liver), 28.1 microg/g (spleen) and 0.2 microg/g (bone marrow) after 7 days. Our data suggest that the critical organ for the treatment with LMA could be the bone marrow, since it has low Sb levels and, presumably, high rates of Sb elimination. A multiple dose treatment with LMA seems to be necessary for complete elimination of parasites from bone marrow in dogs with visceral leishmaniasis.

Distribution of liposome-encapsulated antimony in dogs

The achievement of complete cure in dogs with visceral leishmaniasis is currently a great challenge, since dogs are the main reservoir for the transmission of visceral leishmaniasis to humans and they respond poorly to conventional treatment with pentavalent antimonials. In order to improve the efficacy of treatment, we developed a novel formulation for meglumine antimoniate based on the encapsulation of this drug in freeze-dried liposomes (LMA). The aim of the present study was to evaluate the biodistribution of antimony (Sb) in dogs following a single intravenous bolus injection of LMA. Four healthy male mongrel dogs received LMA at 3.8 mg Sb/kg body weight and were sacrificed 3, 48 and 96 h and 7 days later. Antimony was determined in the blood, liver, spleen and bone marrow. In the bone marrow, the highest Sb concentration was observed at 3 h (2.8 æg/g wet weight) whereas in the liver and spleen it was demonstrated at 48 h (43.6 and 102.4 æg/g, respectively). In these organs, Sb concentrations decreased gradually and reached levels of 19.1 æg/g (liver), 28.1 æg/g (spleen) and 0.2 æg/g (bone marrow) after 7 days. Our data suggest that the critical organ for the treatment with LMA could be the bone marrow, since it has low Sb levels and, presumably, high rates of Sb elimination. A multiple dose treatment with LMA seems to be necessary for complete elimination of parasites from bone marrow in dogs with visceral leishmaniasis

Comparaçäo entre o teste imunoenzimático e a reaçäo de imunofluorescência indireta no diagnóstico sorológico da leishmaniose tegumentar americana canina experimental / Comparison between the enzyme-linked immunossorbent assay and the indirect fluorescent antibody test in the diagnosis of canine experimental tegumentar leishmaniasis

Trinta e um cäes foram inoculados experimentalmente com Leishmania (Viania) braziliensis e acompanhados clínica e laboratorialmente por 539 dias. O teste imunoenzimático (ELISA) e a reaçäo de imunofluorescência indireita (IFI) foram utilizados no acompanhamento da resposta imune humoral e avaliados como métodos de diagnóstico durante a evoluçäo da doença. Os resultados apontam maior sensibilidade do ELISA, indicando ser este método mais adequado que IFI como auxiliar para o diagnóstico sorológico da leishmaniose tegumentar americana canina

Thyroxin plasmal levels and sulfamethoxazol-Timetrhoprim total clearance in dogs

Os níveis plasmáticos de tiroxina (T4) foram determinados por radioimunoensaio em 9 cäes, antes da administraçäo, em dose única, via intramuscular ou intravenosa, de uma associaçäo (5:1) sulfametoxazol (SMT) - trimetropina (TMP), tendo a dose (30 mg/kg) sido calculada em relaçäo ao SMT. O clearance total (Clt) foi calculado para ambos os componentes da associaçäo após dosagem das concentraçöes sanguíneas, a intervalos regulares. Os níveis médios de T4 foram 1,01 mais ou menos 0,25 ug/dl, o Clt para o SMT e o TMP foram 1,38 mais ou menos 0,41 e 0,20 mais ou menos 0,04 l/kg/h respectivamente. Näo houve correlaçäo significativa entre os níveis de T4 e os valores de Clt para SMT ou para TMP