Synovial fluid and radiographic evaluation of joints from dogs with visceral leishmaniasis.

BACKGROUND: Polyarthritis has been associated with canine visceral leishmaniasis (CanVL), and co-infection with Ehrlichia canis is common and may alter clinical manifestations. METHODS: A total of 89 dogs presenting CanVL were subdivided into two groups: (1) G1, consisting of 46 dogs seronegative to Ehrlichia spp., and (ii) G2, consisting of 43 dogs seropositive to Ehrlichia spp. Eight joints (carpal, tarsal, stifles and elbows) from each dog were evaluated by radiography and synovial fluid (SF) cytologic analysis. RESULTS: Overall, 74 of the 89 (83.1%) dogs presented joint abnormalities suggestive of osteoarthritis by radiography (G1: 40/46 [86.9%]; G2: 34/43 [79.0%]), with no statistically significant between-group difference. All dogs with abnormal joint X-ray images presented radiographic lesions bilaterally, independent of the characteristics of the lesion. Soft tissue swelling around the joint and joint space narrowing were more commonly observed in G1 than in G2 dogs. There was no significant between-group difference in terms of other radiographic abnormalities suggestive of osteoarthritis (evident trabecular pattern, subchondral bone sclerosis, osteolysis, osteolytic-proliferative lesions or bone proliferation). SF from 174/315 (55.2%) and 152/307 (49.5%) joints from G1 and G2 dogs, respectively, presented an inflammatory infiltrate, but there was no significant association between the presence of inflammatory infiltrate and group. There was also no statistical difference between groups in either of the evaluated joints in terms of the percentage of neutrophils or mononuclear cells. Leishmania spp. amastigotes were found in 69/315 (21.9%) joints from G1 dogs and in 100/307 (32.5%) joints from G2 dogs (Fisher's exact test, P = 0.002, odds ratio = 0.5, 95% confidence interval = 0.4-0.8). The neutrophilic infiltrate was significantly higher in joints with amastigote forms in both G1 (Mann-Whitney U-test, U(18) = 817, Z = -3.76, P = 0.0001) and G2 dogs (Mann-Whitney U-test, U(18) = 6543, Z = - 5.06, P < 0.0001). CONCLUSIONS: A high prevalence of arthritis in dogs with CanVL was found, and all dogs presented involvement in multiple joints. Although no difference was observed between groups in terms of the number of dogs with polyarthritis and the presence of an inflammatory infiltrate in SF, Leishmania spp. amastigotes were found more frequently in joints from G2 dogs. Further studies evaluating SF in dogs co-infected with L. infantum and E. canis should be performed to evaluate this finding.

Chromosomal segments may explain the antibody response cooperation for canine leishmaniasis pathogenesis.

Visceral leishmaniasis (VL) is marked by hyperactivation of a humoral response secreting high quantity of immunoglobulins (Igs) that are inaccessible to intracellular parasites. Here we investigated the contributions of the antibody response to the canine leishmaniasis pathogenesis. Using correlation and genome-wide association analysis, we investigated the relationship of anti-Leishmania infantum immunoglobulin classes levels with parasite burden, clinical response, renal/hepatic biochemical, and oxidative stress markers in dogs from endemic areas of VL. Immunoglobulin G (IgG) and IgA were positively correlated with parasite burden on lymph node and blood. Increased IgG, IgA and IgE levels were associated with severe canine leishmaniasis (CanL) whereas IgM was elevated in uninfected exposed dogs. Correlations of IgM, IgG and IgA with creatinine, urea, AST and ALT levels in the serum were suggested an involvement of those Igs with renal and hepatic changes. The correlogram of oxidative radicals and antioxidants revealed a likely relationship of IgM, IgG and IgA with oxidative stress and lipid peroxidation in the blood, suggested as mechanisms mediating tissue damage and CanL worsening. The gene mapping on chromosomal segments associated with the quantitative variation of immunoglobulin classes identified genetic signatures involved with reactive oxygen species generation, phagolysosome maturation and rupture, free iron availability, Th1/Th2 differenciation and, immunoglobulin clearance. The findings demonstrated the roles of the antibody response as resistance or susceptibility markers and mediators of CanL pathogenesis. In addition we pinpointed candidate genes as potential targets for the therapy against the damage caused by exacerbated antibody response and parasitism in VL.

High concentrations of glucose reduce the oxidative metabolism of dog neutrophils in vitro.

BACKGROUND: Dogs are commonly affected by hyperglycemic conditions. Hyperglycemia compromises the immune response and favors bacterial infections; however, reports on the effects of glucose on neutrophil oxidative metabolism and apoptosis are conflicting in humans and rare in dogs. Considering the many complex factors that affect neutrophil oxidative metabolism in vivo, we investigated in vitro the specific effect of high concentrations of glucose on superoxide production and apoptosis rate in neutrophils from healthy dogs. RESULTS: The capacity of the neutrophils to reduce tetrazolium nitroblue decreased significantly in the higher concentration of glucose (15.13 ± 9.73% (8 mmol/L) versus 8.93 ± 5.71% (16 mmol/L)). However, there were no changes in tetrazolium nitroblue reduction at different glucose concentrations when the neutrophils were first activated with phorbol myristate acetate. High concentrations of glucose did not affect the viability and apoptosis rate of canine neutrophils either with or without prior camptothecin stimulation. This study provides the first evidence that high concentrations of glucose inhibit the oxidative metabolism of canine neutrophils in vitro in a manner similar to that which occurs in humans, and that the decrease in superoxide production did not increase the apoptosis rate. CONCLUSIONS: A high concentration of glucose reduces the oxidative metabolism of canine neutrophils in vitro. It is likely that glucose at high concentrations rapidly affects membrane receptors responsible for the activation of NADPH oxidase in neutrophils; therefore, the nonspecific immune response can be compromised in dogs with acute and chronic hyperglycemic conditions.

Evaluation of cytologic and biochemical variables in blood, plasma, and peritoneal fluid from calves before and after umbilical herniorrhaphy.

OBJECTIVE: To establish reference intervals for cytologic and biochemical variables in peritoneal fluid, whole blood, and plasma in calves with congenital umbilical hernias (CUHs) before and after herniorrhaphy and to assess whether those variables in calves with CUHs were altered, compared with findings in clinically normal calves. ANIMALS: 20 Holstein calves with or without a CUH. Procedures-10 calves with CUHs underwent herniorrhaphy. Blood and peritoneal fluid samples from all 20 calves were collected for cytologic and biochemical analyses on days 0 (before surgery), 1, 3, 5, 7, and 15. Data from the 2 groups were compared. RESULTS: Reference intervals for the variables of interest were established for each group. Before surgery, calves with CUHs had significantly greater plasma total protein concentration and creatine kinase (CK) and aspartate aminotransferase activities and peritoneal fluid specific gravity values, compared with values for calves without CUHs. At various time points after surgery, peritoneal fluid total protein concentration; fibrinogen concentration; nucleated cell, polymorphonuclear cell, and lymphocyte counts; specific gravity; and lactate dehydrogenase, aspartate aminotransferase, and CK activities in calves with CUHs were significantly different from values in calves without CUHs. Some plasma and blood variables (eg, total protein concentration, neutrophil count, and CK activity) were significantly different between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: Values of certain cytologic and biochemical variables in peritoneal fluid, blood, and plasma were different between calves with and without CUHs. Thus, determination of reference intervals for these variables is important for interpreting diagnostic test results in calves with CUHs.

Metabolismo oxidativo dos neutrófilos de ovinos tratados com monensina sódica e experimentalmente submetidos à acidose ruminal / Oxidative metabolism of the neutrophils in sheep treated with sodium monensin and experimentally submitted to ruminal acidosis

A acidose láctica ruminal é causada pela ingestäo excessiva de carboidratos de fermentaçäo rápida sem uma prévia adaptaçäo dos mocroorganismos, podendo com isso gerar distúrbios metabólicos graves aos ruminantes. Este trabalho tem por objetivo estudar o metabolismo oxidativo dos neutrófilos em ovinos tratados com a monensina sódica na acidose láctica ruminal induzida experimentalmente. Foram empregados 18 ovinos, machos, mestiços (Ideal x Merino), fistulados no rúmen; dos quais nove receberam 33 mg/kg da dieta do ionóforo ao dia, durante 30 dias, os demais ovinos pertenceram ao grupo controle. A acidose foi induzida fornecendo 15g de sacarose/kg de peso corporal. A avaliaçäo clínica e as amostras de rúmen e sangüíneas foram obtidas antes (momento controle) 0h e às 6h, 12h, 24h e 48h pós-induçäo. Em ambos os grupos os animais apresentaram manifestaçöes clínicas de acidose láctica ruminal 6 horas pós-induçäo. A partir deste período se observou uma diminuiçäo significativa (p<0,05) do pH no fluido ruminal, que alcançou valores inferiores a cinco, e diferenças significativas (p<0,05) entre os grupos a partir das 12h pós-induçäo foram constatadas, nos quais os ovinos tratados com a monensina apresentaram valores superiores em relaçäo aos do grupo controle. Durante este período ocorreu uma inibiçäo do metabolismo oxidativo dos neutrófilos nos animais estudados, ocorrendo restabelecimento desta funçäo somente nos ovinos que receberam a monensina. O pH sangüíneo, a glicose plasmática e o cálcio ionizável sofreram alteraçöes nos seus índices. A concentraçäo do cortisol sérico elevou-se de forma significativa (p< 0,05) em ambos os grupos, porém diferenças (p< 0,05) entre eles foram constatadas ao final no período de observaçäo. O tratamento com a monensina näo influenciou o metabolismo oxidativo dos neutrófilos, inibido pela acidose láctica; porém se verificou uma recuperaçäo mais rápida deste metabolismo nos animais em que receberam o ionóforo