Neutrophils are a type of white blood cell that play a significant role in the immune system of horses. They are involved in the body's defense mechanisms against infections and are typically one of the first responders to microbial invasion or tissue damage. Neutrophils function by engulfing and destroying pathogens through processes such as phagocytosis and the release of antimicrobial substances. In horses, the number and activity of neutrophils can be indicative of immune status and are often assessed in the context of infectious diseases, inflammation, and other health conditions. This page compiles peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical implications of neutrophils in equine health.
Loftus JP, Williams JM, Belknap JK, Black SJ.Laminitis is a crippling disease of horses characterized by an inflammatory response in the tissue that suspends the axial skeleton within the hoof. Pain is a common feature of laminitic pathology and its management is an important component of the treatment regime for this disease. Systemic lidocaine administration is commonly utilized to manage pain in equine laminitis; however, the potential anti-inflammatory effects of this drug during the treatment of equine laminitis have not been investigated. Here, we sought to determine if lidocaine concentrations achieved in the plasma (therapeutic c...
Beeler-Marfisi J, Clark ME, Wen X, Sears W, Huber L, Ackerley C, Viel L, Bienzle D.To evaluate experimental induction of recurrent airway obstruction (RAO) with inhaled fungal spores, lipopolysaccharide, and silica microspheres in horses. Methods: 7 horses with and 3 horses without a history of RAO. Methods: RAO-susceptible horses ranged in age from 17 to approximately 30 years, and control horses ranged in age from 7 to approximately 15 years. Pure mold cultures were derived from repeated culture of hay and identified via gene amplification and sequencing. Pulmonary function testing and bronchoalveolar lavage were performed before and after nebulization with a suspension of...
Petersson KH, Burr DB, Gomez-Chiarri M, Petersson-Wolfe CS.Horses have an increased susceptibility to infection because of a decline in immune function with advancing age. Vitamin E has been found to play a key role in normal immune system function. The purpose of the study was to examine the effect of vitamin E supplementation on immune function and response to vaccination in older horses. Predominantly older horses (18.9 +/- 1.3 yr, range 7 to 26 yr; 523 +/- 38 kg of BW) were supplemented orally once daily for 16 wk with either all-rac-alpha-tocopheryl acetate (15 IU/kg of BW; n = 8) or a placebo (n = 8). One horse from each group was removed from t...
Péters F, Franck T, Pequito M, de la Rebière G, Grulke S, Salccicia A, Verwilghen D, Chiavaccini L, Deby-Dupont G, Serteyn D.The previous experiments have shown that some phenothiazines have antioxidant and anti-inflammatory properties in vitro. In this study the inhibition of the production of reactive oxygen species (ROS) by neutrophils was studied in two groups of horses, which received a dose of 0.1 mg/kg of either acepromazine or promethazine intravenously. Blood samples were collected before (T0) and 0.5, 1, 3 and 5 h after drug administration. The chemiluminescence (CML) response of neutrophils was measured ex vivo in the presence of luminol for a period of 10 min and the maximum CML value (peak value) record...
Michelotto PV, Muehlmann LA, Zanatta AL, Bieberbach EW, Fernandes LC, Nishiyama A.Inflammatory airway disease (IAD) is prevalent in young racehorses during training, being the 2nd most commonly diagnosed ailment interrupting training of 2-year-old Thoroughbred racehorses. Objective: That stabling and exercise cause oxidative stress, release of platelet-activating factor (PAF) and inflammation in airways of Thoroughbred colts. Methods: Colts in breeding farms (NC, n = 45), stabled for 30 days (EC, n = 40), and race trained (EX, n = 34). Methods: Cytological profile and parameters of bronchoalveolar lavage fluid (BALF) related to oxidative stress, bioactivity of the proinflam...
Gerber V, De Feijter-Rupp H, Wagner J, Venta P, Harkema JR, Robinson NE.Airway mucus accumulation is associated with indoor irritant and allergen exposure in horses with recurrent airway obstruction (RAO). Epidermal growth factor receptor (EGFR) and a chloride channel (calcium activated, family member 1; CLCA1) are key signalling molecules involved in mucin gene expression. Objective: We hypothesised that exposure to irritants and aeroallergens would lead to increased expression of the mucin gene eqMUC5AC and increased stored mucosubstance in the airways of RAO-affected horses, associated with increased neutrophils and CLCA1 and EGFR mRNA levels. Methods: We perfo...
Pickles KJ, Brooks AC, Rickards KJ, Cunningham FM.N-terminal peptides derived from the anti-inflammatory peptide, annexin-1, inhibit neutrophil function but can also induce pro-inflammatory effects. Although equine annexin-1 has been sequenced, its cellular expression and properties have not been reported. This study has examined whether annexin-1 is present in equine leucocytes and how the N-terminal peptide, Ac2-26, affects equine neutrophil superoxide production. Annexin-1 expression in equine neutrophils and mononuclear cells and the ability of Ac2-26 to activate neutrophil p42/44 MAPK were determined by immunoblotting. Equine neutrophil ...
Leclere M, Magdesian KG, Kass PH, Pusterla N, Rhodes DM.The purpose of this study was to compare the clinical, microbiological, radiological, haematological and cytological features of foals with pneumonia caused by Rhodococcus equi infection and with other bacteria, in order to provide markers for early diagnosis and treatment. A retrospective study of 113 cases of bacterial pneumonia was undertaken. Although there was considerable overlap in the affected populations, foals with R. equi pneumonia were significantly younger and had higher respiratory rates. Radiological evidence of thoracic abscessation had a sensitivity of 71% and a specificity of...
Chang MH, Kim KH, Kim HS, Jun HJ, Kim DH, Jang JH, Kim K, Jung CW.Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) plus cyclosporine (CSA) is standard therapy in patients with severe aplastic anemia (SAA) who do not have an available HLA-matched sibling donor. Methods: The current study aimed to determine the predictive factors for response to IST in patients with SAA and to identify prognostic factors following IST. A total of 62 patients diagnosed with SAA who received IST with either rabbit ATG (n = 33) or horse ATG (n = 29) plus CSA between October 1994 and December 2007 were included. Results: With a median follow-up duration of 60.5 mo...
de la Rebière de Pouyade G, Franck T, Salciccia A, Deby-Dupont G, Grulke S, Heyden LV, Sandersen C, Serteyn D.Equine neutrophil elastase (NE) is a protease released in inflammatory diseases and participating in tissue destruction. To measure NE in horse plasma to assess its role in pathological conditions, we purified elastase from equine neutrophils by a double step chromatography and obtained a pure protein of 27 kDa, 4 kDa smaller than the NE 2A previously purified (Scudamore et al., 1993; Dagleish et al., 1999), which was likely to be NE 2B. We developed an ELISA by using two specific polyclonal antibodies obtained from rabbit and guinea pig. The sandwich complex was detected using a secondary ant...
de la Rebière de Pouyade G, Riggs LM, Moore JN, Franck T, Deby-Dupont G, Hurley DJ, Serteyn D.Laminitis is a local manifestation of a systemic inflammatory response that is characterized by neutrophil activation and movement of neutrophils into the laminar tissues. Given the evidence for the involvement of neutrophils in the development of laminitis, we measured concentrations of neutrophil elastase, a serine protease released from the azurophilic granules of neutrophils, in plasma, skin and laminar tissues obtained from control horses and horses given black walnut heartwood extract (BWHE) to induce laminitis. Healthy horses (5-15 years old) were randomly assigned to 4 groups: 3 experi...
Adaszek Ł, Winiarczyk S, Łukaszewska J.The study was aimed at determining the cause of a disease in a horse exhibiting symptoms of fever, joint effusion, weakness, and extravasations on the mucous membranes. Blood was drawn from the animal for haematological and biochemical molecular tests. The PCR technique revealed the presence of 16S RNA Ehrlichia spp. genetic material in the blood samples. DNA amplification by means of primers EHR 521 and EHR 747 gave a product with a volume of 247 bp.The sequence of the PCR product obtained showed a 97.6% similarity with a sequence of a fragment of 16S RNA Ehrlichia phagocytophila, gene number...
Liu M, Liu T, Bordin A, Nerren J, Cohen N.Toll-like receptor 9 (TLR9) activation stimulates protective immune responses against intracellular pathogens by phagocytes, including neutrophils. This study examined TLR9-mediated neutrophil activation in neonatal foals. Unmethylated CpGs, ligands for TLR9, were used to stimulate equine neutrophils, either purified or in contact with other peripheral blood leukocytes. Rhodococcus equi was used as another stimulus in parallel. TLR9 mRNA was constitutively expressed at a similar level in purified equine neutrophils across different ages from birth to adulthood, and expression was not affected ...
Koenig JB, Hart J, Harris DM, Cruz AM, Bienzle D.To evaluate the performance of a chemiluminescent endotoxin activity assay in horses with colic and healthy horses. Methods: 20 horses with colic and systemic inflammatory response syndrome (SIRS group), 8 horses with colic with no SIRS (NSIRS group), and 20 healthy horses. Methods: Venous blood was collected into EDTA blood collection tubes after completion of a physical examination, and a chemiluminescent endotoxin activity assay was performed within 60 minutes of collection. Medical or surgical interventions and outcome were recorded for each horse. Results: Mean + or - SE endotoxin activit...
Reyner CL, Wagner B, Young JC, Ainsworth DM.To examine gene expression of selected cytokines in pulmonary mononuclear cells isolated from healthy horses and horses susceptible to recurrent airway obstruction (RAO), and to determine whether interleukin (IL)-17 and IL-23 were associated with pulmonary inflammation. Methods: 6 RAO-susceptible and 5 healthy horses. Methods: Bronchoalveolar lavage cells were retrieved from horses that were stabled and fed dusty hay for 24 hours. Lavage cells devoid of neutrophils were incubated for 24 hours with solutions of PBS, hay dust, lipopolysaccharide, or B-glucan. Gene expression of IL-17, IL-23 (p19...
Newquist JM, Baxter GM.To determine whether high plasma fibrinogen concentration (> or = 900 mg/dL) is a valid indicator of physeal or epiphyseal osteomyelitis in foals. Methods: Retrospective case series. Methods: 17 foals with physeal or epiphyseal osteomyelitis with or without septic arthritis, 17 foals with septic arthritis alone, 20 foals with non-Rhodococcus equi pneumonia, and 22 healthy foals. Methods: Medical records were reviewed for information regarding signalment and total WBC count, segmented neutrophil count, and plasma fibrinogen concentration measured when foals were initially evaluated at the ho...
Faleiros RR, Leise BB, Westerman T, Yin C, Nuovo GJ, Belknap JK.C-X-C motif ligand 1 (CXCL1) is an important chemokine of epithelial origin in rodents and humans. Objective: To assess in vivo and in vitro the regulation of CXCL1 in equine laminitis. Methods: Twenty adult horses. Methods: Real-time quantitative polymerase chain reaction (PCR) was used to assess expression of CXCL1 in samples of laminae, liver, skin, and lung from the black walnut extract (BWE) model of laminitis, and in cultured equine epithelial cells (EpCs). Tissue was obtained from control animals (CON, n = 5), and at 1.5 hours (early time point [ETP] group, n = 5), at the onset of leuko...
de la Rebière de Pouyade G, Serteyn D, Deby-Dupont G, Franck T.Neutrophil myeloperoxidase (MPO) and elastase can be released in severe inflammatory diseases and cause tissue injuries. Equine enzymes have already been individually purified from large blood quantities. We describe the isolation of both enzymes from a same limited blood volume. Both MPO and elastase were extracted by crushing PMN isolated by centrifugation on a percoll-gradient from a 460 ml blood collection. MPO and elastase were separated by an ionic exchange chromatography phase and further purified by gel filtration chromatography on Superdex 200 and 75, respectively. Enzymes were identi...
Dunkel B, Rickards KJ, Werling D, Page CP, Cunningham FM.Recurrent airway obstruction (RAO) in mature horses is characterized by reversible airway obstruction and neutrophilic inflammation; there is also functional activation of circulating platelets and neutrophils. This study was undertaken to determine if changes in activation marker expression and heterotypic aggregate formation can be used as an indicator of this increased functional responsiveness. In vitro conditions for flow cytometric measurement of CD13, CD41/61 and CD62P expression on activated cells and heterotypic aggregate formation were established. Values were then compared before an...
Franck T, Kohnen S, de la Rebière G, Deby-Dupont G, Deby C, Niesten A, Serteyn D.Neutrophil (PMN) contribution to the acute inflammatory processes may lead to an excessive generation of reactive oxygen metabolites species (ROS) and secretion of granule enzymes. We compared the effects of either phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) in combination with a pre-treatment by cytochalasin B (CB) on the production of ROS and the release of total and active myeloperoxidase (MPO) by isolated equine PMNs. The ROS production was assessed by lucigenin dependent chemiluminescence (CL) and ethylene release by alpha-keto-gamma-methylthiobutyric...
Treonze KM, Alves K, Fischer P, Hagmann WK, Hora D, Kulick A, Vakerich K, Smith ND, Lingham RB, Maniar S, Reger TS, Zunic J, Munoz B, Prasit P....The purpose of this study was to characterize the alpha(4)beta(1) receptor (CD49d/CD29, very late antigen-4, VLA-4) on circulating equine leukocytes and to evaluate the intrinsic potency of an alpha(4)beta(1) receptor antagonist (Compound B) in the horse. Ultimately, these studies would allow us to determine the suitability of treating recurrent airway obstruction (RAO; heaves) affected horses by blocking the cellular recruitment of lymphocytes and neutrophils into the lung. The data demonstrates the alpha(4)beta(1) integrin is present on horse lymphocytes and neutrophils (fluorescence-assiste...
Kusano K, Hobo S, Ode H, Ishikawa Y.Cytology of tracheal aspirates, tracheal endoscopic and blood tests were carried out to 86 Thoroughbred racehorses presenting coughs or poor performance which were suspected to have lower respiratory tract disease (LRTD) to assess the conditions of the disorders. Racehorses were classified into coughing (66 horses) and non-coughing (20 horses) groups based on clinical symptoms. Nine Thoroughbred racehorses without respiratory abnormality were used as controls. Assessment of grades of airway mucus, cytology of tracheal aspirates and serum amyloid A (SAA), fibrinogen (Fbg) and pulmonary surfacta...
Cook VL, Neuder LE, Blikslager AT, Jones SL.The effect of lidocaine on in vitro migration and adhesion of equine neutrophils was evaluated. Neutrophils were isolated from equine whole blood using a Percoll-gradient centrifugation protocol. Purified neutrophils were incubated with lidocaine at concentrations from 0.1 to 1000 microg/ml for 30 min at 37 degrees C, after calcein loading. Neutrophil integrin-mediated adhesion in response to stimulation with 100 nM LTB(4), 100 nM PAF, or 100 ng/ml IL-8, or integrin-mediated migration in response to stimulation with 100 nM LTB(4), 150 nM PAF, or 100 ng/ml IL-8 was assessed. Statistical signifi...
Lavoie JP, Thompson D, Hamilton E, Debrue M, David F, Hickey G.It has been suggested that many of the beneficial effects of corticosteroids are mediated through mitogen-activated protein kinase (MAPK) p38 inhibition. Objective: To investigate the efficacy of the MAPK p38 inhibitor compound MRL-EQ1 to either prevent (Phase 1) or treat (Phase 2) recurrent airway obstruction (RAO) in horses. Methods: MRL-EQ1 was administered i.v. at a dosage of 0.75-1.5 mg/kg bwt q. 12 h. In Phase 1, susceptible horses in clinical remission were divided into 2 groups (n = 5/group), based on historical values of respiratory mechanics. All horses were entered in the study in p...
Eckert RE, Sharief Y, Jones SL.Equine laminar tissues do not contain resident neutrophils and have less superoxide dismutase (SOD) activity than other equine tissues, which makes them inherently more vulnerable to damage induced by reactive oxygen species (ROS) produced by neutrophils that enter the tissues. In the advanced clinical stages of acute laminitis, pathologic events in affected feet include a breakdown in the basement membrane, neutrophil infiltration, and platelet-neutrophil aggregates in laminar dermal veins, highlighting the contribution of neutrophils to the pathophysiology of the disease. The aim of this stu...
Brooks AC, Menzies-Gow NJ, Wheeler-Jones C, Bailey SR, Cunningham FM, Elliott J.The endothelium plays a major role in the pathogenesis of endotoxemia. Binding of endotoxin (lipopolysaccharide; LPS) to endothelium initiates a range of signalling events, including activation of p38 mitogen activated protein kinases (MAPKs) that are involved in the initiation of inflammatory responses. In the present study we have examined whether clinically relevant concentrations of LPS can activate p38 MAPK in equine endothelial cells and have investigated the role of the kinase in neutrophil adhesion and mediator release. Cultured equine digital vein endothelial cells (EDVEC) were expose...
Alghamdi AS, Lovaas BJ, Bird SL, Lamb GC, Rendahl AK, Taube PC, Foster DN.Bovine semen is naturally deposited in the vagina and spermatozoa migrate through the cervix into the uterus leaving the bulk of seminal plasma (SP) behind. In equine, both spermatozoa and SP are deposited directly in the uterus and SP reduces sperm binding to neutrophils and prevents the formation of DNA-based neutrophil extracellular traps (NETs). We investigated the role of bovine SP on sperm-neutrophil binding using the four most common bovine semen extenders. Contrary to equine, bovine spermatozoa removed from SP had low binding to neutrophils for up to 3h, but as little as 10% SP increas...
Nerren JR, Payne S, Halbert ND, Martens RJ, Cohen ND.Rhodococcus equi is an intracellular pathogen of macrophages that causes rhodococcal pneumonia in foals and immunocompromised people. Evidence exists that neutrophils play a vital role in resistance to infection with R. equi; however, the means by which neutrophils exert their effects have not been clearly defined. In addition to directly killing bacteria, neutrophils also may exert a protective effect by linking innate and adaptive immune responses. In the present study we evaluated the cytokine expression profiles of adult equine neutrophils in response to stimulation with isogenic strains o...
Lecoq L, Vincent P, Lavoie-Lamoureux A, Lavoie JP.Glucocorticoids have potent anti-inflammatory properties and are frequently used for the treatment of domestic animal species, including horses. They induce a down-regulation of multiple inflammatory pathways through both genomic and non-genomic effects. Currently, little is known on the effects of glucocorticoids on equine peripheral blood neutrophils. Objective: Dexamethasone (DEX), a potent synthetic glucocorticoid, inhibits the functions of equine peripheral blood neutrophils through both genomic and non-genomic effects. Methods: Six healthy adult mixed breed female horses. Methods: To ass...
Nerren JR, Martens RJ, Payne S, Murrell J, Butler JL, Cohen ND.Although evidence exists that neutrophils play a vital role in resistance to infection with Rhodococcus equi, the means by which neutrophils exert their effects have not been clearly defined. In the present study we evaluated differences in cytokine expression by unstimulated and R. equi-stimulated neutrophils obtained from newborn foals and subsequently at 2-, 4-, and 8-weeks of age. Stimulation with virulent R. equi induced significantly (P<0.05) greater expression of IFNgamma, TNFalpha, IL-6, IL-8, IL-12p40, IL-12p35, and IL-23p19 mRNA relative to expression by unstimulated neutrophils, ...
Troedsson MH, Scott MA, Liu IK.Four intrauterine treatment strategies were evaluated for effectiveness in mares that were confirmed to be susceptible to chronic uterine infection. Pretreatment samples were obtained at detection of estrus, and a genital strain of Streptococcus zooepidemicus was infused into the uterus when a preovulatory (> 35 mm) follicle was detected. At 12 hours after inoculation, mares were assigned to 1 of 4 selected treatment groups: autologous plasma, 100 ml (n = 5); potassium penicillin, 5 million U in 100 ml of phosphate-buffered saline solution (PBSS; n = 5); 10 mg of prostaglandin F2 alpha in 1...
Brazil TJ, Dixon PM, Haslett C, Murray J, McGorum BC.The aim of this study was to characterise constitutive apoptosis in equine peripheral blood neutrophils, including assessment of factors that potentially modulate neutrophil survival through alteration of the rate of constitutive apoptosis. Cells underwent spontaneous time-dependent constitutive apoptosis when aged in culture for up to 36 h, developing the structural and functional features of apoptosis observed in many cell types, including human neutrophils. Neutrophils undergoing apoptosis also had diminished zymosan activated serum (ZAS)-stimulated chemiluminescence, but maintained respo...
Rumbaugh GE, Smith BP, Carlson GP.internal abdominal abscesses in 25 horses, including 8 horses that died or were euthanatized, were found to be caused by Streptococcus equi, Streptococcus zooepidemicus, or Corynebacterium pseudotuberculosis. Breed or sex predilection was not found. Although horses of all ages were affected, those under 5 years of age were more commonly affected. Nearly all of the horses had a history of respiratory catarrh or lymphadenitis. Horses with internal abdominal abscesses also had intermittent, prolonged colic or chronic weight loss. Most horses had increased rectal temperature, increased heart and r...
Pickles K, Pirie RS, Rhind S, Dixon PM, McGorum BC.The aim of this study was to develop a diagnostically useful smear method for preparation of equine bronchoalveolar lavage fluid (BALF) for use by practitioners. A smear method for equine BALF preparation which included the addition of serum was developed, and cell morphology, differential cell counts (DCC) and repeatability of counting DCC compared with those of cytocentrifuged BALF preparations. BALF samples (n = 21) were collected from 5 control horses and 5 heaves-susceptible horses. Smear preparations of BALF produced smaller, darker, staining cells, making cytological identification more...
Reyner CL, Wagner B, Young JC, Ainsworth DM.To examine gene expression of selected cytokines in pulmonary mononuclear cells isolated from healthy horses and horses susceptible to recurrent airway obstruction (RAO), and to determine whether interleukin (IL)-17 and IL-23 were associated with pulmonary inflammation. Methods: 6 RAO-susceptible and 5 healthy horses. Methods: Bronchoalveolar lavage cells were retrieved from horses that were stabled and fed dusty hay for 24 hours. Lavage cells devoid of neutrophils were incubated for 24 hours with solutions of PBS, hay dust, lipopolysaccharide, or B-glucan. Gene expression of IL-17, IL-23 (p19...
Journal of proteomicsMarch 26, 2022
Volume 261 104571 doi: 10.1016/j.jprot.2022.104571
Koziy RV, Bracamonte JL, Yoshimura S, Chumala P, Simko E, Katselis GS.Septic arthritis (SA) is a life-threatening condition in horses, and identifying eradication of infection in equine SA is challenging. This study explored the discovery of putative biomarkers for the eradication of joint infection in horses. We performed proteomics analysis of synovial fluid (SF) and plasma from horses with experimental SA, non-septic lipopolysaccharide-induced arthritis, and controls. The point of eradication of infection in horses with SA was determined previously. We compared spectral intensities between groups as well as before and after the eradication of infection. Twent...
Watson ED, Stokes CR, David JS, Bourne FJ.The bactericidal and phagocytic activities of blood neutrophils suspended in uterine washings and the mobilization of neutrophils into the uterine lumen were studied in ovariectomized mares receiving oestradiol benzoate (N = 4), progesterone (N = 4) or oily vehicle (N = 4). Uterine lavage was performed sequentially up to 144 h after induction of endometritis by intrauterine infusion of glycogen (1%). There was no significant difference between the 3 groups in speed of mobilization of neutrophils into the uterus in the first 6 h after infusion but there were significantly more uterine luminal n...
van der Haegen A, Künzle F, Gerber V, Welle M, Robinson NE, Marti E.Recurrent airway obstruction (RAO) is a common condition in stabled horses characterised by small airway inflammation and obstruction following exposure of susceptible horses to mouldy hay and straw. The aim of the present study was to investigate whether lung tissue from horses with RAO contains higher numbers of IgE-protein positive (+) cells and mast cells compared to controls after mouldy hay challenge. Furthermore, mast cell subtypes in lung tissue were investigated. IgE+ cells were detected in most lung tissue samples but no significant differences between RAO-affected and control horses...
Secombe CJ, Lester GD, Robertson ID, Cullimore AM.To characterise the cytological changes in equine bronchoalveolar lavage (BAL) samples over multiple years to determine if the prevalence of a relative mast cell response was influenced by season. Methods: Medical records of 228 horses with clinical signs consistent with non-infectious respiratory disease or poor performance where a BAL was performed were reviewed retrospectively. BAL fluid cytology and categorised clinical variables were analysed using a Chi-square test to determine associations. Results: The predominant signalment was a racing horse between 2 and 6 years of age, and poor ath...
Ogilvie TH, Rosendal S, Blackwell TE, Rostkowski CM, Julian RJ, Ruhnke L.Mycoplasma felis was the only organism recovered from the thoracic cavity of a horse with pleuritis. Large numbers of mildly degenerative neutrophils were in the pleural fluid. The horse developed a serologic response to M felis and recovered during hospitalization. Experimentally, a pony was inoculated in the thoracic cavity with a pure culture of the M felis isolate suspended in the pony's serum. A control pony was inoculated with serum only. Within 48 hours, the principal pony developed fever, increased respiratory rate, pleural effusion, and signs of pain. A highly cellular exudate with no...
Ryhner T, Müller N, Balmer V, Gerber V.The mechanisms leading to mucus accumulation in equine inflammatory airway disease (IAD) and recurrent airway obstruction (RAO) are unclear. In airways of human patients with asthma and/or chronic obstructive pulmonary disease as well as in animal models of these diseases, associations of mucus hyperproduction with increased calcium-activated chloride channel 1 (CLCA1), epidermal growth factor receptor (EGFR), mucin 5AC (MUC5AC), B-cell lymphoma 2 (Bcl-2), interleukin (IL)-13 and interferon (IFN)-gamma expression have been reported. We hypothesized that increased mucus accumulation in RAO and ...
Leclere M, Magdesian KG, Cole CA, Szabo NJ, Ruby RE, Rhodes DM, Edman J, Vale A, Wilson WD, Tell LA.Azithromycin is widely used in foals but has not been studied in adult horses. The goals of this study were to determine the pharmacokinetic profile and to make a preliminary assessment of the safety of azithromycin in adult horses. Azithromycin was administered intravenously (5 mg/kg) and intragastrically (10 mg/kg) to six healthy mares in a crossover design. Serial plasma samples, blood neutrophils, and pulmonary macrophages were collected for the measurement of azithromycin concentrations. Azithromycin was also administered orally (10 mg/kg) once a day for 5 days to five healthy mares for p...
Dunkel B, Rickards KJ, Werling D, Page CP, Cunningham FM.Recurrent airway obstruction (RAO) in mature horses is characterized by reversible airway obstruction and neutrophilic inflammation; there is also functional activation of circulating platelets and neutrophils. This study was undertaken to determine if changes in activation marker expression and heterotypic aggregate formation can be used as an indicator of this increased functional responsiveness. In vitro conditions for flow cytometric measurement of CD13, CD41/61 and CD62P expression on activated cells and heterotypic aggregate formation were established. Values were then compared before an...
Hodgin EC, McGuire TC, Perryman LE, Grant BD.Delayed hypersensitivity (DH) responses of normal and immunodeficient horses were evaluated with antigens [dinitrochlorobenzene (DNCB), keyhole limpet hemocyanin (KLH)] and phytolectins [phytohemagglutinin (PHA), concanavalin A (Con A)]. Immunologically normal horses sensitized with 5 daily applications of 2 mg of DNCB developed positive skin reactions upon challenge with 0.4 mg of DNCB. The delayed onset of the reaction and the predominately mononuclear cell infiltration at the test site indicated these were DH reactions. Normal horses sensitized with 500 microgram of KLH and challenged with ...
Satué K, Muñoz A, Blanco O.In order to investigate the effect of pregnancy on equine hematological profile, venous blood samples were taken from 44 Carthusian broodmares every two weeks during pregnancy, divided into three periods: I (conception to 110 days), II (111-220 days) and III (222 days to delivery). Routine hematological analysis was performed. Packed cell volume (PCV) increased in period II probably as a consequence of the climatic conditions or as a result of physical stress of lactation during period I. After that, a reduction in PCV was found but this was not matched with a similar decrease in total serum p...
Shibata N, Tatsumi N, Tanaka K, Okamura Y, Senda N.The intracellular location of the binding site of antibody against purified myosin prepared from equine leucocytes was investigated in neutrophils and lymphocytes by electron microscopy using peroxidase-labelled antibody method. The myosin extracted from equine leucocytes could bind skeletal muscle F-actin and the formed complex showed the biophysical and biochemical properties and electron microscopic appearance of actomyosin. On immunodiffusion, the leucocyte myosin formed a single precipitin line with its antibody prepared in rabbits. The antibody also formed single precipitin lines with my...
Morales N, Henriquez C, Sarmiento J, Uberti B, Moran G.Neutrophils are terminally differentiated innate effector cells at the first line of host defense. Neutrophil migration within tissues is complex and involves several steps, during which these cells must be able to interpret a variety of chemical and physical signals. Exacerbated neutrophil activity can be harmful to surrounding tissues; this is important in a range of diseases, including equine asthma. Tamoxifen (TX) is a non-steroidal estrogen receptor modulator with effects on cell growth and survival. Previous studies showed that TX treatment in horses with induced acute pulmonary inflamma...
Gregg SR, Barshick MR, Johnson SE.Following strenuous exercise, skeletal muscle experiences an acute inflammatory state that initiates the repair process. Systemic hyaluronic acid (HA) is injected to horses routinely as a joint anti-inflammatory. To gain insight into the effects of HA on skeletal muscle, adult Thoroughbred geldings (n = 6) were injected with a commercial HA product weekly for 3 weeks prior to performing a submaximal exercise test. Gluteal muscle (GM) biopsies were obtained before and 1 h after exercise for gene expression analysis and HA localization. The results from RNA sequencing demonstrate differences in ...
Sanigavatee K, Poochipakorn C, Huangsaksri O, Wonghanchao T, Yalong M, Poungpuk K, Thanaudom K, Chanda M.Strenuous exercise in traditional polo matches creates enormous stress on horses. Hematological and physiological measures may vary across different field-play positions. This study aimed to investigate the effort intensity and the impact of exertion on hematology and heart rate variability (HRV) in polo ponies with different positions. Thirty-two ponies, divided equally into eight teams, were studied. Each comprises forwards (number 1), midfielders (numbers 2 and 3), and defenders (number 4). Team pairs played the first chukka in four low-goal polo matches. Percent maximum heart rate (%HRmax)...
Deniz Ö, Aragona F, Murphy BA, Tümer KÇ, Bozacı S, Fazio F.The global climatic changes pose a substantial threat to the well-being and productivity of both humans and animals. Unassigned: This study examined the impact of climate changes during different seasons over a 3-year monitoring period (2021-2023) on various blood parameters including, white blood cells (WBC), neutrophils, basophils, eosinophils, lymphocytes, and monocytes, hematocrit (HCT), hemoglobin (HGB), red blood cells (RBC), platelets (PLT), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH). The study focused on 25 Tho...
The objective of the present study was to investigate the influence of daily rhythms on the immune and inflammatory systems in horses, considering white blood cell count (WBCs), leukocyte subpopulations (neutrophils, basophils, eosinophils, lymphocytes, and monocytes), CD4+, and CD8+ lymphocyte populations, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Ten Italian Saddle horses (7-12 years old, body weight 480 ± 30 kg) underwent blood sampling every 4 h over a 24-h period. The COSINOR method was used to identify rhythms and their parameters. A one-way ...
Rossier Y, Sweeney CR, Ziemer EL.Bronchoalveolar lavage was performed in 22 horses with pneumonia or pleuropneumonia. All horses had clinical evidence of pneumonia or pleuropneumonia on the basis of physical, radiographic, ultrasonographic, tracheobronchial aspirate or post-mortem findings. Results of lavage fluid analysis were normal in 9 horses, equivocal in 3 horses, and abnormal in 10 horses. Abnormal lavage fluid had increased total cell count, increased relative and absolute neutrophil counts, degenerative neutrophils, and decreased relative and absolute macrophage and lymphocyte counts.
Fernandez NJ, Gilroy CV, Wagg CR, Kwong GPS, Roy MF.The detection of band neutrophils and toxic change via microscopic blood smear review is vitally important, as their presence indicates systemic inflammation. However, in-clinic evaluation of WBC morphology is often limited. Objective: We aimed to determine the agreement between expert raters in the detection of bands and toxic change. Methods: Three board-certified clinical pathologists each evaluated 109 blood smears from horses with acute disease, and 19 control smears from healthy horses. The pathologists determined if bands were present, and if so, the percentage of bands present. They a...
Dorn CR, Coffman JR, Schmidt DA, Garner HE, Addison JB, McCune EL.Colitis due to salmonellae was diagnosed in 9 horses following hospitalization for various reasons at the University of Missouri Veterinary Teaching Hospital, from May, 1971, to April, 1972. Diarrhea, fever, and either a neutrophil count of less than or equal to 3,600/cmm or a rapid decline in neutrophil numbers were specific for salmonellosis. The value of hematologic survelillance in hospitalized Equidae was demonstrated in another group of 9 horses with neutropenia, each of which was promptly treated and did not develop colitis. Bacteriologic culturing of fecal samples from 28 clinically no...
Weiss DJ, Evanson OA, Fagliari JJ, Valberg S.To determine whether platelets become activated and form platelet-neutrophil aggregates during near-maximal treadmill exercise in horses. Methods: 4 Thoroughbreds. Methods: Horses were subjected to 4 standardized exercise tests on a treadmill, and blood samples were collected before exercise, at treadmill speed of 12 m/s, and 5 minutes after exercise. Flow cytometric techniques were used to identify activated platelets, and flow cytometric and microscopic techniques were used to identify platelet-neutrophil aggregates. Results: Platelet-neutrophil aggregates increased from 2.8 +/- 0.4% at rest...
Anderson SL, Duke-Novakovski T, Robinson AR, Townsend HGG, Singh B.The objective of this study was to determine the effect of pulmonary intravascular macrophage depletion on systemic inflammation and ex vivo neutrophil apoptosis using an experimental model of intestinal ischemia and reperfusion injury in horses. Neutrophils were isolated before and after surgery from horses that were randomized to three treatment groups, namely, sham celiotomy (CEL, = 4), intestinal ischemia and reperfusion (IR, = 6), and intestinal ischemia and reperfusion with gadolinium chloride treatment to deplete pulmonary intravascular macrophages (PIMs, IRGC, = 6). Neutrophil apopt...
Cebulj-Kadunc N, Kosec M, Cestniki V.Total and differential leucocyte counts (lymphocytes, neutrophils, monocytes, eosinophils and basophils) were measured in 140 stallions, 101 mares and 25 foals of Lipizzan breed. The values fell in the normal ranges for warm-blooded horses. Differences between mares and stallions were not significant with the exception of foals, having higher white blood cell, neutrophil, lymphocyte, monocyte and basophil values in females than in males. Foals exhibited an age-related increase of total leucocyte count during the first 4 months of life, accompanied by a decrease in neutrophil and increase in ly...
Floyd K, Suter PF, Lutz H.Direct staining of the granules of blood eosinophils by anti-immunoglobulin fluorescein isothiocyanate (FITC) conjugates was observed when feline blood smears were tested for presence of feline leukemia virus (FeLV) antigen by immunofluorescent antibody. When blood smears of other species including swine, horses, cattle, dogs, sheep, birds, and human beings were examined, direct staining of eosinophils by FITC conjugates was also detected. This FITC staining was restricted to eosinophils and was not observed in neutrophils, lymphocytes, and platelets. Direct FITC staining of eosinophils does n...
Bertram TA, Coignoul FL, Jensen AE.Equine neutrophils were combined with Haemophilus equigenitalis (contagious equine metritis organism; CEMO) or Escherichia coli in low- and high-antibody-titer serum to evaluate the neutrophils ability to phagocytize and kill these bacteria. More E. coli than CEMO were phagocytized at each time period. After 120 min in low-antibody-titer serum, 56.3% of the E. coli and 34.3% of the CEMO were phagocytized. A total of 45% of CEMO and 74.9% of E. coli were phagocytized by 120 min when neutrophils were in high-antibody-titer serum. More than 75% of the ingested E. coli and 90% of the ingested CEMO...
Storms N, Medina Torres C, Franck T, Sole Guitart A, de la Rebière G, Serteyn D.Laminitis is a pathology of the equine digit leading to a failure of the dermo-epidermal interface. Neutrophil activation is recognized as a major factor in SIRS-associated laminitis. Less is known about the role of neutrophil activation in laminitis associated with metabolic disorders. The aim of this descriptive study was to observe whether myeloperoxidase is increased in the laminae during early stage laminitis in three horses subjected to a prolonged euglycemic hyperinsulinemic clamp (pEHC). After 48 h of pEHC-treatment, horses were subjected to euthanasia. Two healthy horses are used as c...
