Histopathological and parasitological study of the gastrointestinal tract of dogs naturally infected with Leishmania infantum

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to provide a systematic pathological and parasitological overview of the gastrointestinal tract (GIT), including the stomach, duodenum, jejunum, ileum, caecum and colon, of dogs naturally infected with <it>Leishmania</it>.</p> <p>Methods</p> <p>Twenty mongrel dogs naturally infected with <it>Leishmania (Leishmania) infantum </it>and obtained from the Control Zoonosis Center of the Municipality of Ribeirão das Neves, Belo Horizonte Metropolitan area, Minas Gerais (MG) state, Brazil, were analyzed. The dogs were divided into two groups: Group 1 comprised nine clinically normal dogs and group 2 comprised 11 clinically affected dogs. After necropsy, one sample was collected from each GIT segment, namely the stomach, duodenum, jejunum, ileum, caecum and colon. Furthermore, paraffin-embedded samples were used for histological and parasitological (immunohistochemistry) evaluation and a morphometrical study were carried out to determine the parasite load (immunolabeled amastigote forms of <it>Leishmania</it>). The Friedman and the Mann Whitney tests were used for statistical analysis. The Friedman test was used to analyze each segment of the GIT within each group of dogs and the Mann Whitney test was used to compare the GIT segments between clinically unaffected and affected dogs.</p> <p>Results</p> <p>The infected dogs had an increased number of macrophages, plasma cells and lymphocytes, but lesions were generally mild. Parasite distribution in the GIT was evident in all intestinal segments and layers of the intestinal wall (mucosal, muscular and submucosal) irrespective of the clinical status of the dogs. However, the parasite load was statistically higher in the caecum and colon than in other segments of the GIT.</p> <p>Conclusion</p> <p>The high parasite burden evident throughout the GIT mucosa with only mild pathological alterations led us to consider whether <it>Leishmania </it>gains an advantage from the intestinal immunoregulatory response (immunological tolerance).</p

In vitro binding and survival assays of Leishmania parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with Leishmania (Leishmania) chagasi

<p>Abstract</p> <p>Background</p> <p>There are a few works considering the characterization of canine monocyte-derived macrophages as well as a standardized procedure for isolation, culture, and infection of these cells with <it>Leishmania</it>. We have performed several modifications in order to improve the canine monocyte-derived macrophage cultures. In addition, we have done a comparative study between monocytes and monocyte-derived macrophages from dogs naturally and experimentally infected with <it>L. chagasi</it>.</p> <p>Results</p> <p>In the presence of exogenous serum, opsonized <it>Leishmania </it>promastigotes binds better to monocytes/macrophages than without serum. Otherwise, this binding occurs due to the strict correlation between the opsonized biologic particles with the third receptor of the complement (CR3-CD11b/CD18). In fact, our assays with CD11b confirmed the importance of this receptor for canine cells and the <it>L. chagasi </it>experimental system. Moreover, monocytes obtained from naturally infected dogs have shown a higher number of monocytes bounded to promastigotes. The experimental results regarding survival have shown that promastigote forms of opsonized <it>L. chagasi </it>were more infective, because we found higher numbers of promastigotes bound to the different cells. As a consequence, after forty-eight hours of binding, higher numbers of amastigotes appeared inside monocyte-macrophages.</p> <p>Conclusion</p> <p>These studies have given support to continue comparative studies involving canine monocytes, monocyte-derived macrophages and peritoneal macrophages. Since we have standardized the canine cell culture, we are looking forward to determining the phenotypic properties of these cells before and after <it>L. chagasi </it>infection using flow cytometry.</p

In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with -6

<p><b>Copyright information:</b></p><p>Taken from "In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with "</p><p>http://www.biomedcentral.com/1746-6148/3/11</p><p>BMC Veterinary Research 2007;3():11-11.</p><p>Published online 30 May 2007</p><p>PMCID:PMC1894629.</p><p></p>Average of peritoneal macrophages binding to from experimental infected animals with the presence or absence of C5D serum, after 50 min incubation (2,5 × 10parasites/well). (C) Average of infected peritoneal macrophages binding to from naturally infected animals with the presence or absence of C5D serum after, fourth eight hour incubation (5 × 10parasites/well) (*) p < 0.01

In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with -7

<p><b>Copyright information:</b></p><p>Taken from "In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with "</p><p>http://www.biomedcentral.com/1746-6148/3/11</p><p>BMC Veterinary Research 2007;3():11-11.</p><p>Published online 30 May 2007</p><p>PMCID:PMC1894629.</p><p></p>(B) Average of monocyte-derived macrophages binding to from experimental infected animals with the presence or absence of C5D serum, after 50 min incubation (5 × 10parasites/well). (C) Average of infected peritoneal macrophages binding to from experimental infected animals with the presence or absence of C5D serum after, fourth eight hour incubation (5 × 10parasites/well) (*) p < 0.01

In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with -2

<p><b>Copyright information:</b></p><p>Taken from "In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with "</p><p>http://www.biomedcentral.com/1746-6148/3/11</p><p>BMC Veterinary Research 2007;3():11-11.</p><p>Published online 30 May 2007</p><p>PMCID:PMC1894629.</p><p></p>/well) (*) p < 0.01. (B) promastigotes bound to monocytes from dogs naturally and experimental infected with in the absence of C5D serum (2.5 × 10parasites/well) (*) p < 0.01

In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with -1

<p><b>Copyright information:</b></p><p>Taken from "In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with "</p><p>http://www.biomedcentral.com/1746-6148/3/11</p><p>BMC Veterinary Research 2007;3():11-11.</p><p>Published online 30 May 2007</p><p>PMCID:PMC1894629.</p><p></p>e of promastigotes bound to monocytes of animals experimentally infected (AEI) with in the presence or absence of C5D serum (2,5 × 10parasites/well) (*p < 0.01)

In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with -5

<p><b>Copyright information:</b></p><p>Taken from "In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with "</p><p>http://www.biomedcentral.com/1746-6148/3/11</p><p>BMC Veterinary Research 2007;3():11-11.</p><p>Published online 30 May 2007</p><p>PMCID:PMC1894629.</p><p></p>e of C5D serum. (C) Promastigotas adhesion with the absence of serum. (D) Note some amastigotas could be seen 48 hours after interaction with the absence of C5D serum Giemsa. 1000×

In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with -0

<p><b>Copyright information:</b></p><p>Taken from "In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with "</p><p>http://www.biomedcentral.com/1746-6148/3/11</p><p>BMC Veterinary Research 2007;3():11-11.</p><p>Published online 30 May 2007</p><p>PMCID:PMC1894629.</p><p></p>overslips (assay with absence of serum C5D). Giemsa. 1000×

In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with -3

<p><b>Copyright information:</b></p><p>Taken from "In vitro binding and survival assays of parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with "</p><p>http://www.biomedcentral.com/1746-6148/3/11</p><p>BMC Veterinary Research 2007;3():11-11.</p><p>Published online 30 May 2007</p><p>PMCID:PMC1894629.</p><p></p>C) CD11b positive cells; (D) CD11b expression during the binding to mononuclear cells with the presence of C5D serum. () CD11b expression during the binding to mononuclear cells with the absence of C5D serum