The aim of the present study was to investigate TLR2 expression in peripheral blood monocytes from dogs naturally infected with Leishmania (Leishmania) infantum to determine whether it correlates with CD11b/CD18 (CR3) expression, and to evaluate the potential of dogs as sources of infection using phlebotomine xenodiagnosis. Forty eight dogs were serologically diagnosed with L. infantum infection by indirect immunofluorescence antibody test (IFAT) and enzyme linked immunosorbent assay (ELISA). Parasitological exams from bone-marrow aspirates were positive by PCR analysis. All dogs were clinical defined as symptomatic. Ear skin tissue samples were obtained for immunohistochemistry (IHQ) analysis. The potential of these dogs as a source of infection using phlebotomine xenodiagnosis (XENO) was evaluated. Flow cytometry was carried out on peripheral blood mononuclear cells using superficial receptors including CD14, CD11b, TLR2 and MHCII. IHQ ear skin tissue parasite load and XENO where done where we found a strict correlation (r = 0.5373). Dogs with higher expression of MFI of CD11b inside CD14 monocytes were represented by dogs without parasite ear tissue load that were unable to infect phlebotomines (IHQ−/XENO−). Dogs with lower expression of MFI of CD11b inside CD14 monocytes were represented by dogs with parasite ear tissue load and able to infect phlebotomines (IHQ+/XENO+) (p = 0,0032). Comparable results were obtained for MFI of MHCII (p = 0.0054). In addition, considering the population frequency of CD11b+TLR2+ and CD11b+MHCII+, higher values were obtained from dogs with IHQ−/XENO− than dogs with IHQ+/XENO+ (p = 0.01; p = 0.0048, respectively). These data, together with the TLR2 and NO assays results (CD11b+TLR2+ and NO with higher values for dogs with IHQ−/XENO− than dogs with IHQ+/XENO+), led to the conclusion that IHQ−/XENO− dogs are more resistant or could modulate the cellular immune response essential for Leishmania tissue clearance.
We propose that canine visceral leishmaniasis (CVL) is a systemic fibrotic disease, as evidenced by the wide distribution of fibrosis that we have found in the dogs suffering from chronic condition. The inflammatory cells apparently direct fibrosis formation. Twenty-four cases (symptomatic dogs) were identified from a total of one hundred and five cases that had been naturally infected with Leishmania chagasi and had been documented during an epidemiological survey of CVL carried out by the metropolitan area of the municipality of Belo Horizonte, MG, Brazil. The histological criterion was intralobular liver fibrosis, as has been described previously in dogs with visceral leishmaniasis. In addition to the findings in the liver, here we describe and quantify conspicuous and systemic deposition of collagen in other organs, including spleen, cervical lymph nodes, lung and kidney of all the infected symptomatic dogs. Thus we report that there is a systematic fibrotic picture in these animals, where inflammatory cells appear to direct fibrosis in all organs that have been studied. Therefore we propose that CVL is a systemic fibrotic disease.
Hymenaea stigonocarpa (Mart. Ex Hayne), popularly known as jatobá-do-cerrado, is a fruit tree widely distributed in the Brazilian Savanna, has multiple uses and is a promising genetic resource. This study aimed to physically characterize fruits and seeds of H. stigonocarpa, as well as to estimate the phenotypic variability at three hierarchical levels: populations, mother trees within populations, and fruits/seeds within mother trees. Fruits from six mother trees were sampled from each of the 25 natural populations found in the Brazilian Savanna. The morphometric characterization of 742 fruits was carried out by evaluating 10 quantitative traits in fruits and seeds. In addition, comparative analyses were performed between the average values of H. stigonocarpa and the botanical variety H. stigonocarpa var. brevipetiolata. Significant phenotypic variations were noticed at all hierarchical levels. A high phenotypic differentiation among the populations was observed for quantitative traits (fruit mass and size, pulp mass and seed mass), being higher when H. stigonocarpa var. brevipetiolata was included in the analysis.
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