Stress response after race and endurance training sessions and competitions in Arabian horses.

Assuring a high level of animal welfare is a critical aspect of contemporary animal husbandry. Equine athletes begin their careers at a very young age when they are still developing and they are both physically and mentally immature. Lack of scientific knowledge of the stress related to horse racing impedes the development of optimal training programs to attain equilibrium between the best sport results and optimal welfare. This study aimed to determine the influence of the intensity and type of physical activity on peripheral blood cortisol concentration. Thirty untrained Arabians, 9 endurance and 21 race horses were enrolled in this longitudinal study. Blood samples were analysed every 3-weeks in 4 training sessions and 2 races in racing horses and monthly after 2 training sessions and 1 competition in endurance horses. Cortisol concentration was measured at rest and 30 min. after physical effort. Racing horses were divided into two groups of the best and the worst performers. Cortisol concentration increased significantly after training and competition, however both in racing and endurance horses the increase was more intensive after competition. In the racing horses, cortisol concentration tended to gradually increase after the subsequent trainings during the racing season, however the starting gate did not appear to exert any impact on cortisol concentration. The best performing race horses appeared to have a lesser increase in cortisol concentration after the race than the worst performing horses, however the cortisol concentration after the race was not significantly different between these two groups of horses. This study suggests that an optimal training program can induce a stress response which is likely not to have any harmful impact on an athlete's welfare. The more intense effort associated with competition events, both in race and endurance horses, results in a greater stress response, indicating that these kinds of events should be limited to assure animal welfare. Finally, better performance horses adapt more readily to physical activity as they experience less increase of serum cortisol concentration after the race.

Serum amyloid A in equine health and disease.

Serum amyloid A (SAA) is the major acute phase protein in horses. It is produced during the acute phase response (APR), a nonspecific systemic reaction to any type of tissue injury. In the blood of healthy horses, SAA concentration is very low, but it increases dramatically with inflammation. Due to the short half-life of SAA, changes in its concentration in blood closely reflect the onset of inflammation and, therefore, measurement of SAA useful in the diagnosis and monitoring of disease and response to treatment. Increases in SAA concentration have been described in equine digestive, reproductive and respiratory diseases and following surgical procedures. Moreover, SAA has proven useful for detection of some subclinical pathologies that can disturb training and competing in equine athletes. Increasing availability of diagnostic tests for both laboratory and field use adds to SAA's applicability as a reliable indicator of horses' health status. This review article presents the current information on changes in SAA concentrations in the blood of healthy and diseased horses, focussing on clinical application of this biomarker.

The cyclooxygenase-2/prostaglandin E2 pathway and its role in the pathogenesis of human and dog hematological malignancies.

The overexpression of cyclooxygenase-2 (COX-2) has been documented in many types of cancer occurring in humans and animals. Increasing evidences have shown that the overexpression of COX-2 and increased production of prostaglandin E2 (PGE2) correlate with poor prognosis in human solid tumours and hematological malignancies. Both, in vitro and in vivo studies have demonstrated that increased proliferation of cancer cells as well as an impairment of anti-tumour immunity are influenced by the overexpression of this enzyme. In leukemia and lymphoma, an increased activity of COX-2 and subsequent increase in prostaglandins (PGs) concentration allow cancer cells to evade immune response and contribute to metastases. Cancer stem cells (CSCs) in tumour microenvironment, suppression of innate and adaptive immunity depends on COX-2/PGE22 axis activity which increases in hematological malignancies. Cyclooxygenases inhibitors block the formation of PGs, consequently inhibiting angiogenesis, and in some malignancies they decrease cancer cells proliferation and tumour invasiveness. They also increase apoptosis of CSCs and cancer cells, decrease their drug resistance as well as enhance the host immune response. Therefore COX-2/PGE2 axis suppressors: selective COX-2 inhibitors or PG receptors antagonists have been considered as promising anticancer drugs. In comparative oncology dogs are increasingly used as a large animal model because they share the same environmental conditions with people and are exposed to the same environmental factors and also due to their relatively short life span. In dogs, spontaneously occurring non-Hodgkin lymphomas and leukemias have a large number of genetic and morphological features that are similar to those of humans' corresponding cancers. This, additionally makes the species a useful model for the study of new therapeutic strategies in human oncology. While the influence of COX-2 activity and PGE2 receptors have been evaluated extensively in human cancer, their role in veterinary oncology still needs to be elucidated.

The biology of extracellular vesicles with focus on platelet microparticles and their role in cancer development and progression.

Extracellular vesicles (EVs) are a heterogeneous group of structures which can be classified into smaller in size and relatively homogenous exosomes (EXSMs)-spherical fragments of lipid bilayers from inner cell compartments-and bigger in size ectosomes (ECSMs)-a direct consequence of cell-membrane blebbing. EVs can be found in body fluids of healthy individuals. Their number increases in cancer and other pathological conditions. EVs can originate from various cell types, including leukocytes, erythrocytes, thrombocytes, and neoplastic cells. Platelet microparticles (PMPs) are the most abundant population of EVs in blood. It is well documented that PMPs, being a crucial element of EVs signaling, are involved in tumor growth, metastasis, and angiogenesis and may participate in the development of multidrug resistance by tumor cells. The aim of this review is to present the role of PMPs in carcinogenesis. The biology and functions of PMPs with a particular emphasis on the most recent scientific reports on EV properties are also characterized.

Flow cytometric assessment of activation of peripheral blood platelets in dogs with normal platelet count and asymptomatic thrombocytopenia.

Platelets play a crucial role in hemostasis. Their activation has not yet been evaluated in healthy dogs with a normal and low platelet count. The aim of this study was to determine the influence of activators on platelet activation in dogs with a normal platelet count and asymptomatic thrombocytopenia. 72 clinically healthy dogs were enrolled. Patients were allocated into three groups. Group 1 consisted of 30 dogs with a normal platelet count, group 2 included 22 dogs with a platelet count between 100 and 200×109/l and group 3 consisted of 20 dogs with a platelet count lower than 100×109/l. Platelet rich-plasma (PRP) was obtained from peripheral blood samples using tripotassium ethylenediaminetetraacetic acid (K3-EDTA) as anticoagulant. Next, platelets were stimulated using phorbol-12-myristate-13-acetate or thrombin, stabilized using procaine or left unstimulated. The expression of CD51 and CD41/CD61 was evaluated. Co-expression of CD41/CD61 and Annexin V served as a marker of platelet activation. The expression of CD41/CD61 and CD51 did not differ between the 3 groups. Thrombin-stimulated platelets had a significantly higher activity in dogs with a normal platelet count than in dogs with asymptomatic thrombocytopenia. Procaine inhibited platelet activity in all groups. In conclusion, activation of platelets of healthy dogs in vitro varied depending on the platelet count and platelet activator.

The influence of experimental administration of low zearalenone doses on the expression of Th1 and Th2 cytokines and on selected subpopulations of lymphocytes in intestinal lymph nodes.

The aim of this study was to characterize the immune response taking place in ileocecal lymph nodes (ICLN) in control (n=15) and zearalenone (ZEN)-treated (n=15) pigs. The experiment was carried out over 42 days; a dose of 0.1 mg kg-1 feed day-1 of ZEN was administered to the animals. The dose used in the experiment was at a level where no adverse effects are observed (NOAEL) in the ovaries, uterus and vagina. ICLN samples for analysis were collected on the 14th, 28th and 42nd day of the experiment. The analysis of cytokine concentration in the tissues showed that pigs treated with ZEN had an increased level of cytokines produced by helper Th1 lymphocytes (IL-2, IL-12 and IFN-γ) on the 28th day of the experiment. The level of cytokines produced by helper Th2 lymphocytes (IL-4 and IL-10) was characterized by a statistically non-significant upward trend, as compared with the control group. Flow cytometry showed a linear decrease in the percentage of CD21+ B, CD2+ T and CD4+CD8- T cells and an increase in the percentage of CD8+CD4- and TCRγδ + T cells in pigs treated with ZEN. Both ZEN and α-ZEL (α-zearalenone) concentrations increased over time in the liver, but only ZEN concentration increased in ICLN. The results obtained demonstrate that a NOAEL concentration of ZEN shifts the immune response in pig ICLN towards Th1/Th17, probably with a simultaneous activation of M1 macrophages. Moreover, we observed an increase in humoral cytokine secretion; this can be explained by a negative feedback loop and a phenotypic switch of macrophages from M1 to M2, as well as a switch of immune response from Th1 to Th2 type. ZEN can therefore influence the process of cytokine secretion and the percentage of lymphocytes in ileocecal lymph nodes.

Evaluation of reticulated platelets in dogs with breed-related thrombocytopenia.

The aim of this study was to evaluate the percentage of reticulated platelets in healthy dogs with breed-related thrombocytopenia. Seventy two dogs, clinically healthy, were enrolled in the study. Blood was collected from the patients and anticoagulated with tripotassium ethylenediaminetetraacetic acid (K3-EDTA) and sodium citrate. Platelet count was obtained by an impedance haematology analyser and platelet morphology was evaluated by examination of blood smears. Patients were allocated into two groups. Group 1 consisted of 30 dogs with normal platelet count, whereas group 2 was composed of 42 dogs with thrombocytopenia. Thrombocytopenia was present in both K3-EDTA and citrate blood samples. Patients with thrombocytopenia were divided into two subgroups: the first subgroup included dogs with platelet count in K3-EDTA anticoagulated blood from 100 to 200 x10(9)/L, patients in the second subgroup had a platelet count of less than 100 x10(9)/L. The percentage of young reticulated platelets (RPs) labelled with thiazole orange, and the percentage of platelets coated with platelet surface-associated IgG, were determined in platelet-rich plasma (PRP) by a flow cytometer. The mean percentage of RPs in K3-EDTA and citrate PRP was significantly higher in dogs with thrombocytopenia than in dogs with normal platelet count. The mean percentage of RPs was significantly higher in citrate PRP than in K3-EDTA PRP in all groups. The results suggest that idiopathic, asymptomatic thrombocytopenia is not caused by platelet surface-associated IgG. Dogs with breed-related thrombocytopenia have a competent bone marrow.

The effect of T-2 toxin on percentages of CD4+, CD8+, CD4+ CD8+ and CD21+ lymphocytes, and mRNA expression levels of selected cytokines in porcine ileal Peyer's patches.

The immune system is one of the main toxicity targets of the T-2 toxin. In view of scant research data demonstrating the effect of T-2 on cellular and humoral responses in gut-associated lymphoid tissue (GALT), this study set out to investigate the effects of chronic exposure to low doses of the T-2 toxin (200 microg T-2 toxin kg(-1) feed) on percentages of CD4+ and CD8+ T lymphocytes, CD4+/CD8+ double-positive T lymphocytes, CD21+ B cells, and IL-2, IFN-gamma, IL-4 and IL-10 mRNA expression levels in porcine ileal Peyer's patches. The investigated material comprised ileum sections sampled from piglets (aged 8-10 weeks, body weight of 15-18 kg) on days 14, 28 and 42 of the experiment. After 42 days of exposure to T-2, a significant drop in the quantity of the IL-10 product was observed (R = 0.94; S.E. 0.49-0.79; p < 0.001). A gradual decrease in the amount of IL-4 and IFN-gamma cytokine transcripts was found throughout the experiment, but the reported trend was not significant. On experimental days 14 and 42, a significant increase in the percentage of CD8+ T lymphocytes was observed in comparison with the control (p = 0.04 and p = 0.05, respectively), whereas on day 28, a significant decrease in the percentage of the above subpopulation was noted (p = 0.00). The percentage of CD21+ B cells in the experimental group decreased steadily in comparison with the control, and the observed drop was significant on days 28 and 42 (p = 0.06 and p = 0.00, respectively). On days 14 and 28, the percentages of CD4+ and CD8+ T lymphocytes were lower in the experimental animals than in the control group, and the drop reported on day 28 was statistically significant (p = 0.03).

Comparison of the influence of EDTA-K3 and sodium citrate on haematology analysis in healthy dogs.

The study was carried out on 30 clinically healthy dogs of various breeds. Haemoglobin concentration, haematocrit, platelet count and platelet haematocrit were significantly lower in citrate blood than in tripotassium ethylenediaminetetraacetic acid (EDTA-K3) blood. The study confirmed the limited usage of sodium citrate in haematology analysis, unless canine EDTA-dependent thrombocytopenia is suspected.