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Topic:Inflammation
Inflammation is a biological response of the horse's body to harmful stimuli, such as pathogens, damaged cells, or irritants. It is a complex process that involves the activation of immune cells, the release of inflammatory mediators, and changes in blood flow. In horses, inflammation can manifest in various forms, affecting different tissues and organs, including the joints, respiratory system, and skin. The inflammatory response is an essential component of the horse's immune system, aiming to eliminate the initial cause of cell injury, clear out damaged cells and tissues, and establish tissue repair. This topic page gathers peer-reviewed research studies and scholarly articles that explore the mechanisms, effects, and management of inflammation in equine health.
Experimental mild pulmonary inflammation promotes the development of exercise-induced pulmonary haemorrhage. Histological studies of exercise-induced pulmonary haemorrhage (EIPH) reveals inflammatory infiltrates within areas of lung that contain haemorrhage. This has resulted in the hypothesis that pulmonary inflammation could cause EIPH or contribute to an increased risk or severity of EIPH. Objective: To determine whether experimentally-induced pulmonary inflammation predisposes the lung to haemorrhage during exercise, by evaluating the bronchoalveolar lavage (BAL) cytology of normal and inflamed regions of lung following high speed treadmill exercise. Methods: Transendoscopic airway inoculations o...
Physiological measurements and prevalence of lower airway diseases in Trotters with dorsal displacement of the soft palate. Dorsal displacement of the soft palate (DDSP) is one of the most common obstructive conditions of the upper respiratory tract in the racehorse. This condition has a complex aetiology which may be caused or exacerbated by pharyngeal inflammation. Additionally, lower respiratory airway diseases may be associated with DDSP thereby contributing to exercise intolerance in these horses. Objective: The aim of this study was to measure physiological variables during a standardised exercise test and to assess the prevalence and consequences of lower respiratory airway disease in horses with DDSP. Metho...
Serum amyloid A level as a potential indicator of the status of endurance horses. Changes in serum levels of acute phase proteins (APPs) reflect the acute phase reaction, a rapid and nonspecific response to any tissue damage. Serum amyloid A (SAA) is the main APP in horses, which increases in various diseases, surgical injuries and after long distance endurance rides; however, this nonspecific parameter has not been investigated as an indicator of subclinical disorders, which may result in elimination during endurance competitions. Objective: To evaluate the serum concentration of SAA as a potential indicator for the status of horses prepared for long distance endurance rid...
Muscular microRNA expressions in healthy and myopathic horses suffering from polysaccharide storage myopathy or recurrent exertional rhabdomyolysis. MicroRNAs (miRNA) are small endogenous noncoding interfering RNA molecules (18-25 nucleotides) regarded as major regulators in eukaryotic gene expression. They play a role in developmental timing, cellular differentiation, signalling and apoptosis pathways. Because of the central function of miRNAs in the proliferation and differentiation of the myoblasts demonstrated in mouse and man, it is assumed that they could be present in equine muscles and their expression profile may be related to the muscle status. Objective: To identify miRNA candidates in the muscles of control and affected horses ...
Cytokine mRNA expression of pulmonary macrophages varies with challenge but not with disease state in horses with heaves or in controls. 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). ...
Evaluation of a risk-screening questionnaire to detect equine lung inflammation: results of a large field study. The diagnosis of equine recurrent airway obstruction (RAO) and inflammatory airway disease (IAD) is based on clinical signs and increased inflammatory cell percentages in the bronchoalveolar lavage (BAL) fluid. Since a BAL is an invasive procedure, a risk-screening questionnaire (RSQ) would be a valuable screening tool for lung inflammation. Objective: To evaluate the accuracy of a RSQ to detect lower airway inflammation (LAI) in a large population of horses. Methods: A standardised BAL was performed in the field on 167 horses in Alberta, Canada. Horses were separated into 3 categories: 1) BAL...
Increased apoptosis of CD4 and CD8 T lymphocytes in the airways of horses with recurrent airway obstruction. Recurrent airway obstruction (RAO, also known as equine heaves) is an inflammatory condition similar to human asthma caused by exposure of susceptible horses to poorly ventilated stable environments. The disease is characterized by neutrophilic airway inflammation, mucus hypersecretion and reversible bronchoconstriction. This inflammatory process is mediated by several factors, including antibodies, cytokines, resident cells of the airway and inflammatory cellular components that arrive in the respiratory tract. An increasing body of evidence has lent support to the concept that a dysregulatio...
Muc5b is the major polymeric mucin in mucus from thoroughbred horses with and without airway mucus accumulation. Mucus accumulation is a feature of inflammatory airway disease in the horse and has been associated with reduced performance in racehorses. In this study, we have analysed the two major airways gel-forming mucins Muc5b and Muc5ac in respect of their site of synthesis, their biochemical properties, and their amounts in mucus from healthy horses and from horses with signs of airway mucus accumulation. Polyclonal antisera directed against equine Muc5b and Muc5ac were raised and characterised. Immunohistochemical staining of normal equine trachea showed that Muc5ac and Muc5b are produced by cells ...
In vitro and ex vivo pharmacodynamics of selected non-steroidal anti-inflammatory drugs in equine whole blood. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenases (COX), and the inhibition of COX-2 rather than COX-1 can limit the onset of NSAID-related adverse effects. The pharmacodynamic properties of eltenac, naproxen, tepoxalin, SC-560 and NS 398 in healthy horses were investigated using an in vitro whole blood assay. To predict COX selectivity in clinical use, eltenac and naproxen were also studied ex vivo after intravenous administration. SC-560 acted as a selective COX-1 inhibitor, tepoxalin as a dual inhibitor with potent activity against COX-1, and NS 398 as a preferential CO...
Modulatory activities of Agelanthus dodoneifolius (Loranthaceae) extracts on stimulated equine neutrophils and myeloperoxidase activity. Agelanthus dodoneifolius DC Danser (Loranthaceae) is used for the treatment of various diseases including asthma. The aqueous and hydroalcoholic extracts have been reported to have anti-inflammatory, spasmolytic and bronchorelaxant activities. The present study investigates the effects of the aqueous decoction and the diethyl ether, ethyl acetate and butanolic fractions of Agelanthus dodoneifolius DC Danser (Loranthaceae) on reactive oxygen species (ROS) production and myeloperoxidase (MPO) release by phorbol 12-myristate 13-acetate (PMA)-stimulated equine neutrophils and on purified equine MP...
Effects of acute hyperinsulinemia on inflammatory proteins in horses. Laminitis is a painful, inflammatory disease of the equine hoof that often results in euthanasia. Elevated plasma insulin concentrations are a predictive factor for laminitis, and in previously healthy horses and ponies, laminitis was induced by infusion of insulin. Thus, we chose to determine if an infusion of insulin would increase plasma concentrations of inflammatory cytokines and cytokine mRNA abundance in subcutaneous adipose tissue, skeletal muscle, and white blood cells. Ten mature Thoroughbred mares received an insulin infusion that elevated plasma insulin concentrations for 6h or an ...
Expression of cyclooxygenase genes in the jejunum of horses during low-flow ischemia and reperfusion. To determine expression of cyclooxygenase (COX) genes 1 and 2 (also called prostaglandin-endoperoxide synthases 1 and 2) and stability of housekeeping gene expression during low-flow ischemia and reperfusion in the jejunum of horses. Methods: 5 healthy adult horses. Methods: Horses were anesthetized, and two 30-cm segments of jejunum were surgically exteriorized. Blood flow was maintained at baseline (untreated) values in 1 (control) segment and was decreased to 20% of baseline (low-flow ischemia) for 75 minutes, followed by 75 minutes of reperfusion, in the other (experimental) segment. Biops...
Mortierella wolfii keratomycosis in a horse. To describe a case of superficial keratomycosis caused by Mortierella wolfii (M. wolfii) in a horse. Methods: A thoroughbred filly was presented with painful right eye of 2 days' duration. A superficial corneal ulcer was observed ventrally together with multifocal punctuate opacities axially. Samples were collected by swabbing and scraping the ulcerated lesion and submitted for microbiologic and cytologic examination. Results: Microscopic evaluation of debrided corneal tissue revealed the presence of nonseptate fungal hyphae, and culture of a corneal swab yielded fungal growth. Medical treat...
Effects of endotoxin and influence of cyclooxygenase-2 on β-adrenergic mediated relaxation in isolated equine digital artery. The effects of endotoxin on β-adrenergic-mediated relaxation were investigated in the equine digital artery (EDA). Possible involvement of cyclooxygenase-2 (COX-2) in endotoxin-induced effects and basal EDA β-adrenoceptor functionality was also evaluated. Endothelium-intact (e(+)) and/or -denuded (e(-)) EDA rings were incubated overnight with lipopolysaccharide (LPS), LPS+NS398 (selective COX-2 inhibitor) or NS398 alone. Vessel rings were then mounted in organ baths and relaxant responses to isoproterenol (ISOP) recorded on U44069-induced pre-contraction. Response to ISOP was further evaluat...
Effect of long-term fluticasone treatment on immune function in horses with heaves. Corticosteroids currently are the most effective pharmacological treatment available to control heaves in horses. Systemically administered corticosteroids have been shown to alter immune response in horses, humans, and other species. Aerosolized administration theoretically minimizes systemic adverse effects, but the effect of inhaled corticosteroids on immune function has not been evaluated in horses. Objective: To evaluate the effects of prolonged administration of inhaled fluticasone on the immune system of heaves-affected horses. Methods: Heaves-affected horses were treated with inhaled f...
Differentiation of viable, apoptotic and necrotic cells in bronchoalveolar lavage fluid of normal horses and horses with recurrent airway obstruction. Proinflammatoric cytokines are released extracellularly during necrosis. These lead to inflammation and destruction of surrounding tissues. The aim of this study was to compare the number of viable, apoptotic and necrotic cells in the bronchoalveolar lavage fluid (BALF) of normal horses and horses with recurrent airway obstruction (RAO) and to determine if fluorescence microscopy is a reliable method for this examination. A group of six normal horses and a group of ten horses with RAO were examined. Samples were assessed using annexin-V and propidium iodide immunofluorescence assay and examine...
Hypoxia and a hypoxia mimetic up-regulate matrix metalloproteinase 2 and 9 in equine laminar keratinocytes. The aim of this study was to determine if hypoxia and the hypoxia mimetic cobalt chloride regulate the activity of matrix metalloproteinase (MMP)-2 and -9 in cultures of equine hoof keratinocytes. These effects were assessed in primary cultures of laminar keratinocytes using gelatin zymography. Incubation of keratinocytes with cobalt chloride significantly increased the levels of active MMP-2 compared to untreated controls. Hypoxia significantly increased the expression of active MMP-2 and -9 in keratinocyte cultures. This up-regulation was observed after 6h and peaked at 24h. The study findin...
Gas-Filled Intradural Cyst within the Cauda Equine. A case of radicular pain that resulted from a gas-filled intradural cyst in an 80-year-old male is described. Temporary improvement of radicular pain was observed after CT-guided aspiration. However, recurrent radicular pain led to surgical treatment. In this report, the authors document the radiologic and intraoperative features of a gas-filled intradural cyst that migrated into the nerve root, and propose an optimal treatment plan based on a review of the literature.
Magnetic resonance imaging findings in horses with septic arthritis. Fourteen horses with septic arthritis underwent high-field (1.5 T) magnetic resonance imaging (MRI). Septic arthritis was diagnosed based on results from historical and clinical findings, synovial fluid analyses and culture, and radiographic, ultrasonographic, arthroscopic, and histopathologic findings. MR findings included diffuse hyperintensity within bone and extracapsular tissue on fat-suppressed images in 14/14 horses (100%), joint effusion, synovial proliferation, and capsular thickening in 13/14 horses (93%), bone sclerosis in 11/14 horses (79%), and evidence of cartilage and subchondra...
Effects of low-dose hydrocortisone therapy on immune function in neonatal horses. Low-dose hydrocortisone (LDHC) therapy modulates inflammatory responses in adults and improves outcomes in some septic adults and neonates, but its immunologic effects have not been evaluated in neonates. The objective of this study was to evaluate effects of LDHC therapy on ex vivo immune function in neonatal horses (foals). We hypothesized that LDHC treatment would dampen proinflammatory responses without impairing neutrophil function. Hydrocortisone (1.3 mg/kg/d i.v.) was administered to foals in a tapering 3.5 d course. Peripheral blood leukocytes were collected from foals before, during, ...
Equine laminitis: comparative histopathology 48 hours after experimental induction with insulin or alimentary oligofructose in standardbred horses. Laminitis has many triggers and comparing the histopathology of lesions induced by different causes may help to establish whether a common mechanism or multiple pathologies are involved. The aim of this study was to describe the microscopical lesions and to quantify morphometric changes in the lamellae of horses with insulin-induced (n=4) and oligofructose (OF)-induced laminitis (n=4) compared with normal controls (n=4). Archived lamellar samples collected during two previous studies were used. Laminitis was induced within 48 h in standardbred horses with either a euglycaemic, hyperinsulinaemi...
Role of oxidative tissue injury in the pathophysiology of experimentally induced equine laminitis: a comparison of 2 models. Oxidative stress reportedly plays a role in sepsis-induced organ dysfunction and failure in many species. In septic horses, laminae are targeted; evidence of laminar oxidative stress has been reported experimentally in the black walnut extract (BWE) model. Carbohydrate (CHO)-induced laminitis may be more similar to clinical sepsis-related laminitis than the BWE model in that animals with CHO-induced disease commonly develop laminar failure. The role of oxidative stress in the CHO model remains unknown. Objective: Markers of oxidative stress will be increased in laminae from horses with BWE- an...
Insulin resistance in equine digital vessel rings: an in vitro model to study vascular dysfunction in equine laminitis. One of the causes of equine laminitis is hyperinsulinaemia, which may be associated with endothelial dysfunction and insulin resistance of vessels. Objective: Insulin resistance can be induced in palmar digital vessels by continued exposure to insulin in vitro. The objective was to evaluate this in vitro model for future studies. Methods: Palmar digital vessel segments were collected immediately after euthanasia from horses with normal insulin/glucose blood values. Four arterial and 4 venous rings (3 mm wide) were prepared and each ring mounted in a tissue bath, containing Tyrode's solution at...
Descriptive results from a longitudinal study of airway inflammation in British National Hunt racehorses. Rates of airway inflammation in young racehorses decrease with time but it is not clear whether this is associated with increasing age or time exposed to the training environment. The structure of the British National Hunt (NH) population allowed closer examination of this relationship. Objective: To compare rates of inflammatory airway disease diagnosed by tracheal sampling (trIAD), and its components, in NH racehorses by age and training history and with published rates in young racehorses. Methods: A prospective, longitudinal study was conducted on 5 NH yards over 2 years. Period sample pre...
A functional turbidimetric method to determine C-reactive protein in horses. A turbidimetric method to determine serum C-reactive protein (CRP) concentration, based on soybean oil-phosphocholine interaction, was performed on horse serum samples to evaluate its potential diagnostic value in veterinary medicine. Intralipid 20% in 0.1 M Tris-calcium buffer (pH 7.5) was added to horse serum. After 30 min of incubation at 37 °C, the CRP-phosphocholine complexes were turbidimetrically, bichromatically (660 nm/700 nm) quantified on a commercial analyzer. Furthermore, comparison between CRP and other inflammatory markers, including white blood cell and neutrophil counts, was ...
Enhanced IL-6 transcriptional response to adenosine receptor ligands in horses with lower airway inflammation. Accumulation of extracellular adenosine has been closely associated with human asthmatic responses. However, the relevance of adenosine signalling in equine airways has not previously been investigated. Objective: To determine the expression of adenosine receptors (AR) in bronchoalveolar lavage (BAL) cells and assess the reactivity of these cells to AR ligands ex vivo, employing IL-6 as readout of adenosinergic inflammatory signalling. Methods: Eight horses with varying degrees of lower airway inflammation and 10 healthy controls were analysed. Expression of AR-subtypes in each BAL sample was ...
Magnesium disorders in horses. Magnesium (Mg) is an essential macroelement that is required for cellular energy-dependent reactions involving adenosine triphosphate and for the regulation of calcium channel function. Subclinical hypomagnesemia is common in critically ill humans and animals and increases the severity of the systemic inflammatory response syndrome; worsens the systemic response to endotoxins; and can lead to ileus, cardiac arrhythmias, refractory hypokalemia, and hypocalcemia. This article discusses the clinical signs, consequences, and treatment of hypomagnesemia in horses and describes the association of Mg...
Effects of extracorporeal shock wave therapy on desmitis of the accessory ligament of the deep digital flexor tendon in the horse. To evaluate the effects of extracorporeal shock wave therapy (ESWT) on collagenase-induced lesions in the accessory ligament of the deep digital flexor tendon (ALDDFT) of horses. Methods: Paired, blinded controlled study. Methods: Eight Thoroughbred horses (3 mares, 5 geldings; mean ± SD weight, 464 ± 26 kg, mean age, 8 ± 1.7 years). Methods: Lesions were created in both ALDDFTs of all horses by injection of 2 × 10(3) IU of collagenase type I. Percent lesion and structure (fiber alignment and echogenicity) were quantified with ultrasonographic imaging 3, 6, and 9 weeks after collagenase ...
