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.
Lambert JL, Fernandez NJ, Roy MF.Band cells and toxic neutrophils are thought to indicate acute and severe systemic illness but no studies have investigated their importance in adult equine emergency admissions. Objective: The objective of this study was to evaluate the association of band cells and toxic neutrophils with systemic inflammatory response syndrome (SIRS) and outcome in horses. Methods: One hundred and five adult horses admitted on emergency basis to a private primary referral practice. Methods: Prospective observational study with sample collection. All horses admitted on emergency basis over the study period we...
Orard M, Depecker M, Hue E, Pitel PH, Couroucé-Malblanc A, Richard EA.The aim of the study was to determine whether instillation of either 250 mL or 500 mL of saline for bronchoalveolar lavage (BAL) would influence cytological confirmation of inflammatory airway disease (IAD). Thirty client-owned Standardbred racehorses were sampled via endoscopy with 250 mL of saline in one lung and 500 mL in the contralateral lung. The procedure was repeated 72 h later, reversing the volume per lung. The proportions of BAL fluid (BALF) recovered were significantly higher and neutrophil percentages significantly lower with the larger volume. A poor agreement was found between m...
Murcia RY, Vargas A, Lavoie JP.Glucocorticoids (GCs) are the most effective drugs for the treatment of human asthma. However, a subgroup of asthmatic patients with neutrophilic airway inflammation is insensitive to GCs. Interleukin-17 (IL-17), a cytokine upregulated in the airways of a subset of human asthmatic patients, contributes to the recruitment of neutrophils and induces a glucocorticoid resistance in human airway epithelial cells. We hypothesized that IL-17 similarly activates neutrophils and contributes to their persistence in the asthmatic airways in spite of glucocorticoid therapy. To determine whether IL-17 dire...
Aoki T, Kimura Y, Oya A, Chiba A, Ishii M, Nambo Y.Heavy draft mares potentially have a higher risk of suffering from postpartum fever (PF) than light breed mares. The purpose of this study was to compare hematological and biochemical features between clinically healthy mares (n=40) and PF-affected mares (n=16). Mares were classified as having PF when their rectal temperature rose to >38.5°C within 96 hr of foaling. The numbers of leukocytes, lymphocytes, and neutrophils and the serum magnesium level were significantly lower in PF-affected mares. The serum SAA and NEFA levels were significantly higher in PF-affected mares. Strong inflammation...
Salz RO, Ahern BJ, Boston R, Begg LM.To determine the variation of tracheal mucus scores, tracheal blood scores and transendoscopic tracheal wash (TW) cytology in a population of Thoroughbred (TB) racehorses and assess their association with racing performance. Methods: A total of 220 endoscopic examinations were performed and TWs obtained from 155 TB racehorses. Samples were collected 60-120 min following gallop work. Tracheal mucus score, tracheal blood score and TW cytology were analysed and their association with racing performance assessed. Results: Of the total examinations and samples, 194 from 135 horses fitted the criter...
Lilliehöök I, Tvedten HW, Bröjer J, Edner A, Nostell K.Neutrophil myeloperoxidase content is determined by the Advia 2120 hematology system by staining characteristics. Changes in myeloperoxidase staining are shown by location of neutrophils on Advia peroxidase dot plots and as myeloperoxidase index (MPXI). Significant changes in MPXI have been reported during severe inflammation in horses, dogs, and people but conclusions were inconsistent. Objective: Infusion of endotoxin was used to initiate an inflammatory stimulus under controlled conditions and over a longer time period than in previous studies to document kinetics of changes in neutrophil n...
Allano M, Labrecque O, Rodriguez Batista E, Beauchamp G, Bédard C, Lavoie JP, Leclere M.The aim of this study was to determine the effects of short distance transportation on airway mucus, cytology and bacterial culture to identify potential biases in the diagnosis of airway diseases in referral centres. Eight healthy adult horses were studied using a prospective cross-over design. Mucus scores, tracheal wash (cytology, bacterial culture) and bronchoalveolar lavage fluid (BALF; cytology) were obtained while stabled and following 2.5 h transportation (with and without hay). Neutrophil counts, percentages and BALF neutrophilia frequency increased following transport without hay (...
Troedsson MH, Woodward EM.Equine endometritis is characterized by the expression of pro- and anti- inflammatory cytokines and an influx of polymorphonuclear neutrophils (PMNs) into the uterus. Mares resistant to persistent endometritis clear the inflammation within 24-36 h after exposure to microorganisms or semen. These mares have a rapid increase of pro-inflammatory cytokines and an upregulation of inflammatory modulating cytokines within 6h after exposure to inflammatory challenge. In conjunction with effective uterine contractions, these events are believed to be responsible for the transient nature of the inflamma...
Sanchez-Teran AF, Bracamonte JL, Hendrick S, Burguess HJ, Duke-Novakovski T, Schott M, Hoff B, Rubio-Martínez LM.To evaluate the effect of arthroscopic lavage on systemic serum amyloid A (SAA) and SAA, total protein, nucleated cell count, and percentage of neutrophils in synovial fluid in healthy horses. Methods: Prospective experimental study. Methods: Healthy adult horses (n = 6). Methods: Middle carpal joints were randomly assigned to 1 of 2 treatments: arthrocentesis (controls) or arthroscopic lavage, with 30 day washout period between treatments. Synovial fluid and blood samples were collected at 0, 24, 48, 72, 96, and 120 hours. Measurements included systemic and synovial fluid SAA, as well as ...
Sanchez-Teran AF, Bracamonte JL, Hendrick S, Riddell L, Musil K, Hoff B, Rubio-Martínez LM.The objective of this study was to evaluate the effect of through-and-through joint lavage on systemic and synovial serum amyloid A (SAA), total protein, nucleated cell count and percentage of neutrophils in the synovial fluid of six healthy horses. A prospective experimental study was performed where one healthy tarsocrural joint of each horse was randomly assigned to receive repeated through-and-through joint lavage at 0, 48 and 96 h. Synovial fluid and blood samples were collected at 0 (baseline), 24, 48, 72, 96 and 120 h. Systemic and synovial SAA, total protein, nucleated cell count a...
Wysocka B, Kluciński W.The aim of the present study was to compare the grade of discharge accumulation in the tracheal lumen, area of tracheal bifurcation, main bronchi and the tracheal septum thickness with the cytology of the tracheal aspirate (TA) and broncho-alveolar lavage fluid (BALF) in horses with recurrent airways obstruction and inflammatory airway disease from those horses. This study was conducted on 96 horses with RAO, 139 horses with IAD and 10 control horses. In all the horses, both clinical and endoscopic examinations were performed. During endoscopy, a score of mucus accumulation was estimated in 3/...
Perez B, Henriquez C, Sarmiento J, Morales N, Folch H, Galesio JS, Uberti B, Morán G.Neutrophilic asthma is an important disease subgroup, including patients with severe phenotypes and erratic responses to standard treatments. Tamoxifen (TX), a selective estrogen receptor modulator (SERM) used as treatment of human breast cancer, has been shown to induce early apoptosis of equine blood and bronchoalveolar lavage fluid (BALF) neutrophils in vitro. Equine recurrent airway obstruction (RAO) is a naturally occurring neutrophilic condition, closely related with human asthma. Our purpose was to investigate the therapeutic potential of tamoxifen in horses with neutrophilic lung infla...
Westerman TL, Tornquist SJ, Foster CM, Poulsen KP.To evaluate use of serum amyloid A (SAA) and haptoglobin concentrations as prognostic indicators for horses with inflammatory disease in regard to euthanasia, complications, and hospitalization duration and cost. Methods: 20 clinically normal horses and 53 horses with inflammatory disease. Methods: Total WBC count, neutrophil count, and fibrinogen, SAA, and haptoglobin concentrations were determined for clinically normal horses and horses with suspected inflammatory disease. Clinicopathologic values at admission were compared to test the use of SAA and haptoglobin concentrations in predicting ...
Derochette S, Serteyn D, Mouithys-Mickalad A, Ceusters J, Deby-Dupont G, Neven P, Franck T.Excessive neutrophil stimulation and reactive oxygen species (ROS) production are involved in numerous human or horse pathologies. The modulation of the neutrophil NADPH oxidase (NOX) has a great therapeutic potential since this enzyme produces superoxide anion whose most of the other ROS derive. The measurement of NOX activity by cell-free systems is often used to test potential inhibitors of the enzyme. A major drawback of this technique is the possible interferences between inhibitors and the probe, ferricytochrome c, used to measure the activity. We designed the "EquiNox2", a new pharmacol...
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...
McFarlane D, Hill K, Anton J.Immunosuppression leading to opportunist bacterial infection is a well-recognized sequela of equine pituitary pars intermedia dysfunction (PPID). The mechanisms responsible for immune dysfunction in PPID however, are as of yet poorly characterized. Horses with PPID have high concentrations of hormones known to impact immune function including α-melanocyte stimulating hormone (α-MSH) and insulin. α-MSH and related melanocortins have been shown in rodents and people to impair neutrophil function by decreasing superoxide production (known as oxidative burst activity), migration and adhesion. T...
Sandersen C, Bienzle D, Cerri S, Franck T, Derochette S, Neven P, Mouytis-Mickalad A, Serteyn D.Horses commonly suffer from chronic respiratory disease and are also used in large animal models of spontaneous or induced airway inflammation. The anti-inflammatory properties of curcumin are largely described but its low bioavailability precludes its clinical use. NDS27, a lysin salt of curcumin incorporated in beta-cyclodextrine, has high bioavailability and can be administered by inhalation. The aim of this study was to investigate the effects of inhaled NDS27 on inflammatory cytokines and proteins in the broncho-alveolar lavage fluid using a model of neutrophilic airway inflammation. Meth...
Minguet G, Franck T, Joris J, Ceusters J, Mouithys-Mickalad A, Serteyn D, Sandersen C.Volatile anaesthestics have shown to modulate the oxidative response of polymorphonuclear neutrophils (PMNs). We investigated the effects of isoflurane and sevoflurane on the degranulation of total and active myeloperoxidase (MPO) from horse PMNs and their direct interaction with MPO activity. Whole blood from horse was incubated in 1 and 2 minimal alveolar concentrations (MAC) of isoflurane or sevoflurane for 1h and PMNs were stimulated with cytochalasin B (CB) plus N-formyl-méthionyl-leucyl-phenylalanine (fMLP). After stimulation, the plasma was collected to measure total and active MPO by ...
Endo Y, Hobo S, Korosue K, Ootsuka K, Kitauchi A, Kikkawa R, Hidaka Y, Hagio M, Tsuzuki N.The present study evaluated the effects of single-dose filgrastim on hematology in 16 healthy horses after long-distance transportation. Horses were assigned to receive filgrastim (0.23 µg/kg, SC, once; G-CSF group; n=8) or saline (0.9% NaCl) solution (0.3 ml, SC, once; control group; n=8) ≤ 1 hr before transportation. Horses were transported 2,530 km using commercial vans over the course of approximately 44 hr. Clinical examinations and hematologic analyses were performed on all horses before and after transportation. Because the post-transportation white blood cell counts and bacillary ne...
Iwaszko-Simonik A, Niedzwiedz A, Graczyk S, Slowikowska M, Pliszczak-Krol A.Recurrent airway obstruction (RAO) is an allergic disease of horses similar to human asthma, which is characterized by airway inflammation and activation of neutrophils, lymphocytes and platelets. Platelet activation and an increase in circulating platelet-leukocyte aggregates may lead to airway remodeling. The aim of this study was to investigate platelet status in RAO-affected horses based on the platelet morphology and platelet surface expression of CD41/61 and CD62P. Ten RAO-affected horses and ten healthy horses were included in this study. Blood samples were obtained to determine the pla...
Bullone M, Lavoie JP.Animal models have been studied to unravel etiological, immunopathological, and genetic attributes leading to asthma. However, while experiments in which the disease is artificially induced have helped discovering biological and molecular pathways leading to allergic airway inflammation, their contribution to the understanding of the causality of the disease has been more limited. Horses naturally suffer from an asthma-like condition called "heaves" which presents sticking similarities with human asthma. It is characterized by reversible airway obstruction, airway neutrophilic inflammation, an...
Endo Y, Tsuchiya T, Omura T, Nakai K, Korosue K, Ishimaru M, Ishikawa Y, Hobo S.The present study evaluated the effects of single-dose marbofloxacin in protecting horses against fever associated with transportation using 48 healthy Thoroughbreds. All horses were premedicated with interferon-α (0.5 U/kg, sublingually, every 24 hr) for 2 days before transportation and on the day of transportation. Horses were randomly assigned to receive marbofloxacin (2 mg/kg, IV, once; MRFX group), enrofloxacin (5 mg/kg, IV, once; ERFX group) or saline (0.9% NaCl) solution (10 ml, IV, once; control group) ≤1 hr before being transportation. Each group contained 16 horses (8 males, 8 fem...
Cohen ND, Bourquin JR, Bordin AI, Kuskie KR, Brake CN, Weaver KB, Liu M, Felippe MJ, Kogut MH.Neutrophils play an important role in protecting against infection. Foals have age-dependent deficiencies in neutrophil function that may contribute to their predisposition to infection. Thus, we investigated the ability of a CpG-ODN formulated with Emulsigen to modulate functional responses of neutrophils in neonatal foals. Eighteen foals were randomly assigned to receive either a CpG-ODN with Emulsigen (N = 9) or saline intramuscularly at ages 1 and 7 days. At ages 1, 3, 9, 14, and 28, blood was collected and neutrophils were isolated from each foal. Neutrophils were assessed for basal and R...
Richard EA, Depecker M, Defontis M, Leleu C, Fortier G, Pitel PH, Couroucé-Malblanc A.Multiple cytological patterns occur in bronchoalveolar lavage fluid (BALF) of horses with inflammatory airway disease (IAD). Only few data on BALF cytokine profiles are available for horses with IAD, and are limited to mRNA expression. Objective: Cytological profiles of IAD are associated with different BALF immunological pathways. To investigate BALF cytokine concentrations in a large number of horses with neutrophilic IAD. Methods: One hundred and thirty-eight client-owned Standardbred racehorses in active training. Methods: Prospective observational study. BALF samples were obtained from le...
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...
Rebordão MR, Carneiro C, Alexandre-Pires G, Brito P, Pereira C, Nunes T, Galvão A, Leitão A, Vilela C, Ferreira-Dias G.Besides the classical functions, neutrophils (PMNs) are able to release DNA in response to infectious stimuli, forming neutrophil extracellular traps (NETs) and killing pathogens. The pathogenesis of endometritis in the mare is not completely understood. The aim was to evaluate the in vitro capacity of equine PMNs to secrete NETs by chemical activation, or stimulated with Streptococcus equi subspecies zooepidemicus (Szoo), Escherichia coli (Ecoli) or Staphylococcus capitis (Scap) strains obtained from mares with endometritis. Ex vivo endometrial mucus from mares with bacterial endometritis wer...
Millerick-May ML, Karmaus W, Derksen FJ, Berthold B, Robinson NE.Particle mapping within stalls has demonstrated a relationship between particulate concentrations and visible accumulations of tracheal mucus. However, measurement of breathing zone particulate concentrations, which is the most accurate way to measure exposure, has not been performed to determine the relationship between exposures and accumulations of tracheal mucus sufficient to affect performance. Objective: To compare breathing zone particulate exposures between horses with tracheal mucus scores (MS) previously demonstrated to affect performance (MS≥2) and those without (MS = 0) visible t...
Braga PC, Dal Sasso M, Lattuada N, Greco V, Sibilia V, Zucca E, Stucchi L, Ferro E, Ferrucci F.Activated neutrophils (PMNs), the ROS/RNS released by PMNs and the derived inflammatory processes are involved in the pathogenesis and progression of human inflammatory airway diseases. Similar diseases are also present in horses which suffer from recurrent airway obstruction (RAO), exercise-induced pulmonary haemorrhage (EIPH) and inflammatory airway diseases (IAD). Hyaluronic acid (HA) plays numerous roles in modulating inflammatory processes. The aim of this study was to examine whether a preparation of HA (MW 900 000 Da) interferes with ROS/RNS during the course of equine PMN respiratory b...
Bazzano M, Giannetto C, Fazio F, Rizzo M, Giudice E, Piccione G.The aim of the study was to assess changes in some haematological parameters of periparturient mares from the last three months of pregnancy until the third week after foaling. The study was carried out on 15 healthy pregnant mares (Group A) and 7 healthy non-pregnant non-lactating mares (Group B). Blood samples were collected by jugular venipuncture into EDTA tubes and tested for Haematocrit (Hct), Red Blood Cell (RBC), Haemoglobin (Hb), Platelets (Plt) and White Blood Cell (WBC). Peripheral blood smears were also performed to assess changes in the leucocyte differential count. Group A showed...
Woodward MC, Andrews FM, Kearney MT, Del Piero F, Hammerberg B, Pucheu-Haston CM.To characterize the response of skin of nonallergic horses following ID injection of polyclonal rabbit anti-canine IgE (anti-IgE) and rabbit IgG. Methods: 6 healthy horses. Methods: Skin in the cervical area was injected ID with anti-IgE and IgG. Wheal measurements and skin biopsy specimens were obtained before and 20 minutes and 6, 24, and 48 hours after injection. Tissue sections were evaluated for inflammatory cells at 4 dermal depths. Immunohistochemical analysis for CD3, CD4, and CD8 was performed, and cell counts were evaluated. Results: Anti-IgE wheals were significantly larger than IgG...
Steelman SM, Johnson D, Wagner B, Stokes A, Chowdhary BP.Chronic equine laminitis causes persistent pain and lameness in affected animals and often necessitates euthanasia when pain management strategies become ineffective. Published studies as well as anecdotal reports suggest that this chronic inflammatory disease is associated with systemic alterations in immune responsiveness, perhaps involving an autoimmune component. We investigated this broad hypothesis by measuring a variety of immune indicators in healthy control horses (CON) and horses with chronic laminitis (LMN). We found that white blood cells from LMN horses produced more IFNγ than di...
Hue E, Orard M, Toquet MP, Depecker M, Couroucé A, Pronost S, Paillot R, Richard EA.Few data on cytokine profiles in bronchoalveolar lavage fluid (BALF) are available for racehorses with mild/moderate equine asthma (EA); cytological diagnosis being most frequently made from only one lung. The purpose of the study was to compare cytokine mRNA expressions and protein concentrations in BALF from both lungs. As part of a larger study, 250 ml saline was randomly instilled in one lung and 500 ml in the contralateral lung of 30 clinically healthy Standardbred racehorses. This procedure was repeated 72 h later, inversing the volume per lung. Cytological cut-off values for diagnosis o...
Burgess H, Chilton NB, Krakowetz CN, Williams C, Lohmann K.This report describes a case of equine granulocytic anaplasmosis in a horse from Saskatchewan. Morulae were visualized within blood neutrophils, and the diagnosis was confirmed by polymerase chain reaction (PCR). The organism was identified as the human pathogenic strain of Anaplasma phagocytophilum by PCR and DNA sequencing of 3 independent genes. RésuméAnaplasmose granulocytaire chez un cheval de la Saskatchewan. Ce rapport décrit un cas d’anaplasmose granulocytaire chez un cheval de la Saskatchewan. Des morulas ont été visualisées dans les neutrophiles sanguins et le diagnostic a é...
Mönki J, Saastamoinen M, Karikoski N, Norring M, Rajamäki M, Mykkänen A.The effects of bedding material on air quality are important amongst horses worldwide. Respiratory diseases, especially equine asthma, are highly prevalent with air hygiene playing a major role on the pathophysiology of these diseases. The objective of our study was to investigate the effects of four bedding materials on the respiratory signs, tracheal mucus score, and tracheal wash (TW) and bronchoalveolar lavage fluid (BALF) cytology in healthy adult horses. The study design was a prospective controlled cross-over study, and the subjects were healthy adult riding school horses ( = 32) from a...
Dindot SV, Doan RN, Kuskie KR, Hillman PR, Whitfield CM, McQueen CM, Bordin AI, Bourquin JR, Cohen ND.Neonates of all species, including foals, are highly susceptible to infection, and neutrophils play a crucial role in innate immunity to infection. Evidence exists that neutrophils of neonatal foals are functionally deficient during the first weeks of life, including expression of cytokine genes such as IFNG. We hypothesized that postnatal epigenetic changes were likely to regulate the observed age-related changes in foal neutrophils. Using ChIP-Seq, we identified significant differences in trimethylated histone H3 lysine 4, an epigenetic modification associated with active promoters and enhan...
McKenzie HC, Murray MJ.To compare concentrations of gentamicin in serum and bronchial lavage fluid after IV and aerosol administration of gentamicin to horses. Methods: 9 healthy adult horses. Methods: Gentamicin was administered by aerosolization (20 ml of gentamicin solution [50 mg/ml]) and IV injection (6.6 mg of gentamicin/kg of body weight) to each horse, with a minimum of 2 weeks between treatments. Samples of pulmonary epithelial lining fluid were collected by small volume (30 ml) bronchial lavage 0.5, 4, 8, and 24 hours after gentamicin administration. Serum samples were obtained at the same times. All sampl...
Pycock JF, Allen WE.Exudate and uterine flushings were collected at either 30, 60, 120 or 240 mins after intrauterine infusions of Streptococcus zooepidemicus in genitally normal mares during oestrus. Uteri were also flushed without prior induction of endometritis. Protein concentrations in exudate and flushings increased with time and exudate pH decreased with time; the pH of flushings did not alter. Lysozyme and lactate dehydrogenase were present in flushings from non-infected uteri, but concentrations increased with time after infection. Immunoreactive prostaglandin E2 was undetectable before infection, but co...
Bazzano M, Giannetto C, Fazio F, Rizzo M, Giudice E, Piccione G.The aim of the study was to assess changes in some haematological parameters of periparturient mares from the last three months of pregnancy until the third week after foaling. The study was carried out on 15 healthy pregnant mares (Group A) and 7 healthy non-pregnant non-lactating mares (Group B). Blood samples were collected by jugular venipuncture into EDTA tubes and tested for Haematocrit (Hct), Red Blood Cell (RBC), Haemoglobin (Hb), Platelets (Plt) and White Blood Cell (WBC). Peripheral blood smears were also performed to assess changes in the leucocyte differential count. Group A showed...
Mild-moderate equine asthma (MEA) is a common respiratory disorder among racehorses, characterized by lower airway inflammation. Although it is generally agreed that MEA causes poor performance, contrasting results have been reported about the effects of tracheal mucus and the leukocyte populations of the bronchoalveolar lavage (BAL) on performance. This study aims to investigate the associations between airway inflammation and fitness parameters measured during an incremental treadmill test on Standardbred racehorses. For this purpose, the clinical records of 116 Standardbreds subjected to a ...
McGorum BC, Dixon PM.Local transendoscopic endobronchial antigen challenge, which has proved to be a valuable clinical and research technique in the study of human pulmonary hypersensitivity, was evaluated in control and asymptomatic COPD--affected horses. Transendoscopic endobronchial challenges with phosphate-buffered saline (PBS), Micropolyspora faeni extract at 60 and 600 micrograms/ml and mouldy hay extract elicited neutrophilic airway inflammatory responses in control (N = 5-7) and asymptomatic COPD-affected (N = 5-7) horses, as determined by cytological examinations of bronchoalveolar lavage fluid (BALF) ha...
McFarlane D, Hill K, Anton J.Immunosuppression leading to opportunist bacterial infection is a well-recognized sequela of equine pituitary pars intermedia dysfunction (PPID). The mechanisms responsible for immune dysfunction in PPID however, are as of yet poorly characterized. Horses with PPID have high concentrations of hormones known to impact immune function including α-melanocyte stimulating hormone (α-MSH) and insulin. α-MSH and related melanocortins have been shown in rodents and people to impair neutrophil function by decreasing superoxide production (known as oxidative burst activity), migration and adhesion. T...
Snow DH, Ricketts SW, Mason DK.The haematological response to racing and to fast and slow training exercise was investigated in studies involving two populations of horses which differed widely in geographical location, climatic factors and management (Newmarket and Hong Kong). The well documented elevations in erythrocyte parameters were demonstrated and changing responses in leucocyte parameters, resulting in variations in the neutrophil to lymphocyte (N/L) ratio were described. It was shown that the immediate response to the anticipation or stress of exercise was a decrease in N/L ratio in association with an increase in...
Robson PJ, Alston TD, Myburgh KH.An increased susceptibility to bacterial and viral infections of the respiratory tract, which results in a loss of performance, has been reported in racehorses. Much research has focused on the influence of high-intensity exercise of a short duration on immune system function in horses, but scant attention has been given to prolonged endurance exercise as an immune modulator. Objective: The objective of this study was to evaluate the effect of an 80 km endurance race on the monocyte and neutrophil oxidative burst, serum cortisol, glutamine and plasma glucose concentrations in 8 endurance-train...
von Fellenberg R, Kohler L, Grünig G, Pellegrini A.Neutral neutrophil protease, elastase activities, and cytosol protease inhibitors of these enzymes of horses and man were compared. Human neutrophils had 5 times the elastase activity of equine neutrophils, and neutral protease activity was approximately 50% greater in human neutrophils than that in equine neutrophils. Cytosol inhibitors for elastase and neutral proteases were not found in human neutrophils, whereas large amounts were found in equine neutrophils. Using fibrinogen-agarose electrophoresis, 4 cytosol inhibitors of different enzyme specificities were detected. These cytosol inhibi...
Zholobenko A, Mouithys-Mickalad A, Modriansky M, Serteyn D, Franck T.A recent study showed that silymarin, a standardized extract of S. marianum might be used in the prevention of equine laminitis. We investigated the effects of quercetin and some compounds found in silymarin (silybin, taxifolin and dehydrosilybin) on reactive oxygen species (ROS) production and myeloperoxidase (MPO) release by stimulated equine neutrophils (PMNs) and on MPO activity. All compounds (tested between 100 nm and 100 μm) inhibited superoxide anion production by stimulated PMNs in a dose-dependent manner. Dehydrosilybin and quercetin inhibited superoxide production and MPO release...
Olave C, Alvarez P, Uberti B, Morales N, Henriquez C, Folch H, Sarmiento J, Moran G.Neutrophils play an important role in the exacerbation and maintenance of severe equine asthma; persistent neutrophil activity and delayed apoptosis can be harmful to surrounding tissues. Tamoxifen (TX) is a nonsteroidal estrogen receptor modulator with immunomodulatory effects and induces early apoptosis of blood and bronchoalveolar lavage neutrophils from horses with acute lung inflammation. This study investigated if the in vitro effects of tamoxifen are produced by its action on nuclear (α and β) and membrane (GPR30) estrogen receptors in healthy equine neutrophils. Results showed that T...
Joubert P, Cordeau ME, Lavoie JP.Heaves in horses is characterized by lower airway neutrophilic inflammation, and reversible airflow obstruction. Pulmonary macrophages contribute to the inflammation observed in a number of human and animal pulmonary diseases, and it has been postulated that they are responsible for the neutrophilic inflammation present in heaves by the release of cytokines and chemokines. To test this hypothesis, the mRNA expression of TNF-α, IL-1β, IL-8, and MIP-2 by macrophages isolated from bronchoalveolar lavage cells was quantified using real-time RT-PCR in horses with heaves (n-6) and controls (n-6). ...
Miró J, Gutiérrez-Reinoso M, da Silva JA, Fernandes C, Rebordão MR, Alexandre-Pires G, Catalán J, Ferreira-Dias G.Collagen fibers and inflammatory cells are the basis for jenny endometrium Kenney and Doig's classification developed for the mare. The infiltration of a large number of eosinophils in the jenny endometrium is intriguing. Eosinophil and fibroblast produced IL33, which has been related to fibrosis development and chronicity. This work on the endometrium consisted of (i) quantification of collagen type I (COL1A2), type III (COL3A1), and IL33 transcripts; (ii) histological localization and quantification of COL1 and COL3 proteins; and (iii) eosinophil and neutrophil count and correlation with col...
Rossdale PD, Silver M, Ellis L, Frauenfelder H.The changes in plasma cortisol concentration in the immediate postnatal period were examined in 3 groups of newborn foals and the response of the adrenal cortex to exogenous ACTH1-24 (tetracosactrin) was tested in 2 of these groups. In full-term Thoroughbred and Pony foals a rise in plasma cortisol occurred between 0 and 30 min after birth, whereas no significant cortisol changes could be detected within 2 h of birth in the group of prematurely delivered foals. These differences in plasma cortisol between term and premature foals were accompanied by differences in blood pH and lymphocyte and n...
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, ...
Sandersen C, Bureau F, Turlej R, Fiévez L, Dogné S, Kirschvink N, Lekeux P.Nuclear factor-kappaB (NF-kappaB) activity, which is a key regulator of inflammatory gene expression, is increased in bronchial epithelial cells from horses suffering from heaves (a hypersensitivity-associated inflammatory condition of the lung). To determine whether this increased activity extends to distal airways and to other pulmonary cells, cells recovered by broncho-alveolar lavage (BAL) in healthy and heaves-affected horses were assessed for NF-kappaB activity. NF-kappaB activity was much higher in BAL cells from heaves-affected horses, especially during crisis (disease exacerbation), t...
Packer M, Patterson-Kane JC, Smith KC, Durham AE.The histological diagnosis of inflammatory bowel disease (IBD) in horses and other species is subjective, and pathological assessments vary considerably as a result. One important criterion is increased infiltration of the lamina propria by eosinophils, plasma cells, lymphocytes or macrophages, but this is difficult to assess without a knowledge of the normal immune cell populations and potential for individual variation. Retrospective jejunal specimens were analysed from 14 horses aged 13-15 years which had not shown clinical or post-mortem signs of gastrointestinal disease. Populations of pl...
Slauson DO, Skrabalak DS, Neilsen NR, Zwahlen RD.Equine neutrophils (PMN) were isolated from citrated normal blood by density gradient separation on Ficoll-Hypaque to greater than 96% purity and 98% viability and an average of 3.78 x 10(7) PMN/ml. The agonist C5a des Arg was used in serial dilutions of whole zymosan-activated equine plasma (ZAP) or was partially purified from ZAP by column chromatography. Purified equine PMN exhibited rapid aggregation following incubation with C5a des Arg which was further dependent on the availability of divalent cations, especially Mg++. The microfilament disruptive agent cytochalasin B (5 micrograms/50 m...
Rush BR, Flaminio MJ, Matson CJ, Hakala JE, Shuman W.To determine cytologic changes in horses with recurrent airway obstruction (heaves) after administration of aerosolized beclomethasone dipropionate and dexamethasone parenterally. Methods: 6 horses with inducible and reversible heaves. Methods: Episodes of heaves were induced by exposure to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone, parenterally administered dexamethasone, aerosolized propellant), and pulmonary inflammation was evaluated by serial cytologic examination of bronchoalveolar lavage (BAL) fluid samples obtained on days 0, 7...
Malikides N, Hughes KJ, Hodgson JL.To determine whether percentages of neutrophils in tracheal aspirate (TA) samples collected from racehorses are increased after exercise and whether interpretation of results from TA samples taken before and after exercise agree. Methods: Case series of 40 young Thoroughbred and Standardbred racehorses in race training presented for evaluation of poor performance. Methods: TA samples were collected endoscopically from racehorses presented for poor performance 24 h before and 1 to 2 h after high speed treadmill exercise testing. Aliquots of the retrieved fluid were cytocentrifuged and smears we...
Deaton CM, Marlin DJ, Smith NC, Smith KC, Newton RJ, Gower SM, Cade SM, Roberts CA, Harris PA, Schroter RC, Kelly FJ.The relationship between hydrogen peroxide (H2O2) concentration in expired breath condensate (EBC) and cytology of the respiratory tract obtained from tracheal wash (TW) or bronchoalveolar lavage (BAL), and epithelial lining fluid (ELF) antioxidant status is unknown. To examine this we analysed the concentration of H2O2 in breath condensate from healthy horses and horses affected by recurrent airway obstruction (RAO), a condition considered to be an animal model of human asthma. The degree of airway inflammation was determined by assessing TW inflammation as mucus, cell density and neutrophil ...
Demmers S, Johannisson A, Gröndahl G, Jensen-Waern M.The aim of this study was to investigate the phagocytic and killing capacities as well as expression of CD18 of neutrophils obtained from healthy foals from birth to age 8 months. Blood was taken from 6 Standardbred foals at 7 time-points between ages 2-56 days and thereafter once a month. For comparison, cells from 16 mature horses were evaluated. Neutrophil phagocytosis of yeast cells was assessed by flow cytometry after opsonisation with mature pooled serum, autologous serum or anti-yeast IgG. The killing capacity of the neutrophils, as indicated by the oxidative burst, was monitored by che...
Cywińska A, Wyszyńska Z, Górecka R, Szarska E, Witkowski L, Dziekan P, Winnicka A, Schollenberger A.Strenuous exercise is recognized as a stress, which may induce functional immunodeficiency and increase individual susceptibility to infection. It has been shown in equine athletes, that alterations in leukocyte functions occur after moderate and submaximal exertion, however, no data deal with the effect of extreme physical exertion. In this study, we evaluated leukocyte functions (neutrophil oxidative burst and lymphocyte proliferation activity in response to mitogens) in horses following the CEI 3* 162 km endurance ride. Exercise-induced stress was manifested as neutrophilic leukocytosis and...
Donovan DC, Jackson CA, Colahan PT, Norton NN, Clapper JL, Moore JN, Hurley DJ.To evaluate the effects of a standardized exercise test to exhaustion in horses on leukocyte function ex vivo. Methods: 6 Thoroughbred geldings. Methods: Blood samples were obtained from each horse before exercise; at exhaustion (termed failure); and at 2, 6, 24, 48, and 72 hours after exercise to evaluate hematologic changes, rate of leukocyte apoptosis, and leukocyte production of reactive oxygen species (ROS) ex vivo. To assess leukocyte function, leukocyte ROS production in response to stimulation with lipopolysaccharide, peptidoglycan, zymosan, and phorbol myristate acetate was evaluated....
