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.
Kampl B, Dominis-Kramaric M, Bacar-Huskic L.The activities of leukocyte alkaline phosphatase (l-AP) and serum gamma-glutamil transferase (gamma-GT), and total leukocyte counts were determined in horses submitted to the production of hyper immune sera against tetanus (Clostridium tetani). The purpose of this work was to investigate the prospective changes of mentioned parameters in horses under the described circumstances. In addition, the suitability of these parameters in assessing the health condition of the same horses had to be evaluated. The average total leukocyte count increased in one month from the values considered as physiolo...
Dillon AM, Heath MF.The effects of the protein tyrosine kinase inhibitors tyrphostins B42 and B46 on equine platelet function and protein tyrosine phosphorylation (PTP) were assessed. Tyrphostins B42 and B46 (both at 100 microM concentration) produced significant inhibition of thrombin-stimulated equine platelet aggregation. The effect of tyrphostin B46 was also time-dependent. The same concentration of these inhibitors produced very little or no inhibition of platelet-activating factor (PAF)-induced aggregation. The effects of tyrphostins B42 and B46 on thrombin- and PAF-stimulated PTP were generally similar, al...
Laws EG, Freeman DE.Fifteen horses under halothane anesthesia were assigned randomly to three groups of 5 horses each as follows. In group 1, the distal 50% of the small intestine was measured through a ventral midline celiotomy and replaced in the abdomen so that these horses could serve as sham-operated controls. In group 2, the same segment of small intestine was subjected to venous strangulation obstruction (VSO) for 180 min. In group 3, the same segment of small intestine was subjected to VSO for 90 minutes, followed by 90 minutes of reperfusion. Biopsies of small intestine were taken from all horses to asse...
Carter SD, Osborne AC, May SA, Bennett D.To consider the hypothesis that autoimmune mechanisms may contribute to the pathology of equine joint diseases, 3 autoimmune responses were assayed in sera and synovial fluids. IgM-rheumatoid factor and antibodies to heat shock protein 65 kDa were determined by ELISA; anti-nuclear antibodies were assayed by indirect immunofluorescence to whole cell nuclear components. All parameters showed only modest increases, if any and not in a pattern related to disease, although some statistically significant increases were detected. Group analysis showed significantly elevated synovial fluid IgM-rheumat...
Owens JG, Kamerling SG, Stanton SR, Keowen ML.The analgesic effects of the nonsteroidal anti-inflammatory drugs, ketoprofen (2.2 and 3.63 mg/kg bwt) and phenylbutazone (4.4 mg/kg bwt) were compared in 7 horses with chronic laminitis. Hoof pain was quantified objectively by means of an electronic hoof tester and lameness was subjectively graded on a modified Obel scale. Ketoprofen at a dose of 3.63 mg/kg bwt (phenylbutazone equimolar dose) reduced hoof pain and lameness to a greater extent than the 2.2 mg/kg dose and phenylbutazone. These effects were still present at 24 h in 3 of the 4 pain tests, including lameness grade. These data sugg...
Landoni MF, Lees P.A comparative study in horses of the pharmacokinetics (PK) and pharmacodynamics (PD) of 2 extensively used nonsteroidal anti-inflammatory drugs (NSAIDs), flunixin (FXN) and ketoprofen (KTP), was carried out applying PK/PD modelling. To evaluate the anti-inflammatory properties of these drugs a model of acute inflammation, comprising surgically implanted subcutaneous tissue cages stimulated by intracaveal injection of carrageenan, was used. FXN elimination half-life (T1/2 beta) in plasma was 3.37 +/- 1.09 h. However, in exudate a much longer T1/2 beta was obtained (15.99 +/- 3.80 h). Apparent v...
Bilzer T, Planz O, Lipkin WI, Stitz L.Tissues from 9 horses and 1 donkey suffering from natural Borna disease were investigated immunomorphologically. Lymphocytic inflammatory reactions and increased expressions of MHC class I and class II antigen were found in the brain as well as in the trigeminal and olfactory system. Perivascular inflammatory infiltrates were dominated by CD4+ T cells, whereas the majority of CD8+ T cells were disseminated intraparenchymally. No evidence of inflammation was found in the retina. Borna disease virus proteins and nucleic acids were present in the hippocampus, thalamus and medulla oblongata in all...
Maisi P, Paananen M, Koivunen AL.Seventeen trotters, eight healthy and nine with a mild respiratory disease, underwent a submaximal treadmill exercise. Heart rate, breathing frequency, intrapleural pressure difference (IP difference) as well as haematocrit and concentration of lactic acid in blood were monitored before exercise, during exercise and during recovery. The activities of beta-glucuronidase and plasmin, total proteolytic activity and trypsin inhibitory capacity were measured from the tracheal fluid before and after exercise. IP difference significantly increased during exercise and returned to normal values within ...
Oikawa M, Takagi S, Anzai R, Yoshikawa H, Yoshikawa T.Eight young thoroughbred horses, taken 1858 km by road (travelling time, 41 h), were examined to assess the pathological nature of respiratory disease associated with transport. Three of the horses showed clinical abnormalities including pyrexia, coughing, leucocytosis and neutrophilia after the first 20 h of transportation. Endoscopical examination of the trachea revealed exacerbation of airway inflammation as a result of transport in two of the three affected horses. A consistent finding in the affected horses was focal serous neutrophilic pneumonia affecting the cranio-ventral portion of th...
Turner AS, Trotter GW, Powers BE.Bilateral palmar and plantar digital neurectomies were completed in 10 horses (a total of 80 neurectomies) using one of three methods: (1) simple transection (guillotine method); (2) epineural capping; (3) n-butyl cyanoacrylate injected into the epineural sheath to act as a nerve sealant. Horses were regularly evaluated clinically for tenderness in and around the surgical site, as well as skin sensation at the coronary band in the heel region, during the 12-week course of the study. None of the surgical sites exhibited any signs of drainage or infection. Horses were then euthanatized, the nerv...
Ayroud M, Leighton FA, Tessaro SV.Four of five reindeer (Rangifer tarandus tarandus) obtained from a Besnoitia sp.- infected herd at the Assiniboine Park Zoo in Winnipeg, Manitoba, Canada, in October 1989, had evidence of mild dermatitis over the articular surfaces of carpal and tarsal joints. Cysts of Besnoitia sp., either surrounded by inflammatory reactions or without evident host response, were present within the dermis, submucosa of the nasal turbinates, periosteum, tendons, testes and hooves. The light microscopic and histochemical features of Besnoitia sp. from reindeer were indistinguishable from those of other Besnoit...
Palmer JL, Bertone AL, McClain H.A modification of a colorimetric assay was used to determine synovial fluid total and individual sulphated-glycosaminoglycan concentration in various clinical presentations of joint disease in horses. Concentrations of synovial fluid and serum sulphated-glycosaminoglycan (GAG) were measured by the 1,9-dimethylmethylene blue (DMMB) dye assay in normal horses (n = 49), horses with acute (n = 26) or chronic (n = 27) joint disease (defined by clinical, radiographic, and clinicopathological parameters), and horses with cartilaginous lesions at diagnostic arthroscopy, but with normal radiographs and...
Owens JG, Kamerling SG, Barker SA.The pharmacokinetic properties of a single intravenous dose of ketoprofen (2.2 mg/kg) in plasma and synovial fluid were compared in four healthy animals and four horses with experimentally induced acute synovitis. Synovitis was induced by the injection of a 1% solution of sterile carrageenan into the left intercarpal joint. Ketoprofen was administered at the same time as carrageenan infection. The plasma disposition followed a biexponential equation or a two-compartment model in most horses. The plasma harmonic mean half-life in healthy horses (0.88 h) was longer than in horses with synovitis ...
Littlewood JD, Whitwell KE, Day MJ.Résumé- Les commémoratifs, les symptômes, l'histologie et la réponse au traitement d'un cheval de 15 ans atteint de lymphome cutané sont décrits. La jument présente de multiples nodules cutanés depuis 11 ans. Un diagnostic de lymphome cutané est poséà l'examen histologique de biopsies réalisées 2 fois à 4 ans d'intervalle. Des marquages immunihistochimiques identifient ces cellules comme appartenant à la lignée T. Ceci est la première description du marquage immunophénotypique d'un lymphome cutané chez le cheval. La jument a été traitée par des glucorticoïdes intralési...
Billinghurst RC, Fretz PB, Gordon JR.Synovial fluid (SF) was collected at 2, 12 and 26 h post racing from 5 Thoroughbred horses (6 joints) with degenerative joint disease. The effects of serial arthrocentesis on SF TNF alpha levels were controlled for by testing, in parallel, site- and time-matched samples from clinically normal horses (i.e. without arthritis). A significant induction in TNF alpha bioactivity was detected in SF from arthritic joints (compared to the control joints) over the 26 h following racing. After subtraction of values for the arthrocentesis control SF, TNF alpha and protein levels and WBC and mononuclear ce...
Douglas J, Clarke A.Equine demineralized bone matrix, particle size 2 to 4 mm, was implanted SC and IM in 4 foals and 4 adult horses. The implants were removed between 5 and 8 weeks after implantation. Bone formation was induced by SC and IM implantations in all animals. The implantation site had a marked effect on the amount of bone that developed, bone being formed earlier and in greater amounts when the matrix was implanted IM. The amount of bone formed increased with increasing time after matrix implantation at both sites. Demineralized bone matrix implantation also led to formation of small amounts of chondr...
Dabareiner RM, Snyder JR, White NA, Pascoe JR, Harmon FA, Gardner I, Woliner MJ, Pinney D, Sullins KE.Microvascular permeability of the jejunum of clinically normal equids and microvascular permeability associated with 60 minutes of ischemia (25% baseline blood flow) and subsequent reperfusion were investigated. Eight adult horses were randomly allotted to 2 equal groups: normal and ischemic/reperfusion injury. Lymphatic flow rates, mesenteric blood flow, and lymph and plasma protein concentrations were determined at 15-minute intervals throughout the study. Microvascular permeability was determined by estimates of the osmotic reflection coefficient, which was determined when the ratio of lymp...
Boulton EP, Seeherman HJ, Kirker-Head CA, Steckel RR.Laryngotomy incisions for either staphylectomy, ventriculectomy, cordectomy, resection of the palatopharyngeal arch, or subepiglottal cyst removal, were closed primarily in 42 horses. Incisional complications were subcutaneous emphysema (11 horses, 26%), incisional discharge (4 horses, 10%), postoperative fever (4 horses, 10%), incisional abscessation (3 horses, 7%), incisional seroma (2 horses, 5%), and subcutaneous edema (2 horses, 5%). Incisional complications were identified in 22 horses, but only 8 horses (19%) required intervention for incisional healing to occur. Factors such as preoper...
Moore RM, Muir WW, Cawrse M, Bertone AL, Beard WL.Twenty-four horses were randomly allocated to 3 groups. Horses were anesthetized, subjected to a ventral midline celiotomy, and the large colon was exteriorized and instrumented. Group-1 horses served as sham-operated controls. Group-2 horses were subjected to 6 hours of low-flow colonic arterial ischemia, and group-3 horses were subjected to 3 hours of ischemia and 3 hours of reperfusion. Baseline (BL) samples were collected, then low-flow ischemia was induced by reducing ventral colonic arterial blood flow to 20% of BL. All horses were monitored for 6 hours after BL data were collected. Bloo...
Moore RM, Couto CG, Muir WW, Moore BR, Kociba GJ.Twenty-four horses were randomly allocated to 3 groups. All horses underwent a ventral midline celiotomy, and the large colon was exteriorized and instrumented. Group-1 horses served as sham-operated controls, group-2 horses underwent 6 hours of colonic ischemia, and group-3 horses were subjected to 3 hours of ischemia and 3 hours of reperfusion. Baseline blood samples were collected, then low-flow colonic ischemia was induced in horses of groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline. All horses were monitored for 6 hours. Citrated systemic venous (SV) blood sample...
Moore RM, Muir WW, Bertone AL, Beard WL, Stromberg PC.Thirty horses were randomly assigned to 1 of 5 groups. All horses were anesthetized and subjected to ventral midline celiotomy, then the large colon was exteriorized and instrumented. Colonic arterial blood flow was reduced to 20% of baseline (BL) and was maintained for 3 hours. Colonic blood flow was then restored, and the colon was reperfused for an additional 3 hours. One of 5 drug solutions was administered via the jugular vein 30 minutes prior to colonic reperfusion: group 1, 0.9% NaCl; group 2, dimethyl sulfoxide: 1 g/kg of body weight; group 3, allopurinol: 25 mg/kg; group 4, 21-aminost...
Moore RM, Muir WW, Granger DN.Restoration of blood flow after a period of intestinal ischemia is necessary to maintain cell function and viability; however, the reintroduction of oxygen can initiate a cascade of events that exacerbates tissue injury. Intestinal I-R injury is manifested as increased microvascular and mucosal permeability, and mucosal necrosis. Reperfusion injury begins with the accumulation of hypoxanthine from ATP metabolism and the conversion of XDH to XO during ischemia. Upon reperfusion, the XO catalyzes the conversion of hypoxanthine to superoxide radicals in the presence of oxygen. Superoxide radicals...
Darien BJ, Stone WC, Dubielzig RR, Clayton MK.The morphologic changes following ascending colon volvulus result from the interaction of inflammatory and coagulation mediators. The objective of this study was to establish a quantifiable histopathologic scoring system to evaluate the serial pathomorphologic changes during ischemia and reperfusion. Such a scoring system could then be applied to subsequent studies designed to attenuate bowel lesions by regulating activity of individual mediators. Ten normal, healthy adult ponies were randomly divided into two equal groups. Following anesthesia and a 30-minute stabilization period, the colon o...
Rosenkrantz WS.Hopefully, the practitioner has obtained a basic broader knowledge of the options available for topical and systemic equine dermatologic therapy. There are many topical and systemic agents that can aid in the treatment of specific skin disease and there are safer alternatives to glucocorticoid therapy. Because equine dermatology is still in its infancy, there is still much to be learned. The practitioner is encouraged to pay close attention to this specialty because it will continue to evolve rapidly.
Fadok VA.Scaling and/or crusting are common clinical findings associated with equine skin diseases. Scaling and crusting may be associated with pruritic or nonpruritic dermatoses. This article focuses on those conditions that are usually nonpruritic in horses. They include the infectious dermatoses, the keratinization/seborrheic disorders, photosensitization, and the immunologic/inflammatory disorders, including pemphigus foliaceus, equine exfoliative eosinophilic dermatitis and stomatitis, and equine histiocytic dermatitis (sarcoidosis). Clinical signs that help differentiate the various disorders are...
Woods PR.Skin lesions can be associated with many internal diseases. Most organ systems seem to have conditions in which skin lesions can develop. Treatment of the skin lesions in such a situation is palliative. The underlying internal disease must be addressed for resolution of the skin lesions to occur. It is important to view the skin as an integral communicating part of the body and not just as the skin.
Fadok VA.Papules and nodules are common lesions on horses and have a variety of underlying causes. This article addresses inflammatory and congenital nodules primarily, including urticaria, erythema multiforme, those nodules caused by infectious agents, epidermoid and dermoid cysts, and the uniquely equine skin tumor, the sarcoid. The eosinophilic nodules and other tumors are covered elsewhere in this issue. Diagnostic and therapeutic approaches to each of the diseases are emphasized.
Miyamoto A, Kanda J, Nishio A.Transmural nerve stimulation (TNS) induced relaxations in porcine and bovine basilar arteries which were abolished by tetrodotoxin (TTX) and by L-nitro-arginine (LNAG). However, TNS induced contractions in equine basilar artery which were abolished by TTX and by guanethidine, but not by LNAG. These results suggest that the TNS-induced contractions of equine basilar arteries may be mediated by norepinephrine release.
McCarthy MB, Duesterdieck-Zellmer KF, Larson MK.To determine whether Botulinum neurotoxin type A (BoNT-A) ameliorates the effects of interleukin 1 (IL-1) on equine articular cartilage, or exerts negative effects on normal equine articular cartilage homeostasis in vitro. Methods: Articular cartilage explants from 6 healthy femoropatellar joints of 3 adult horses. Methods: Explants were allocated to the IL-1 challenged or unchallenged group, then exposed to 1 of 6 concentrations of BoNT-A (0, 1, 10, 50, 100, or 500 pg/mL) for 96 hours. To assess BoNT-A's effects on inflammation, prostaglandin E2 (PGE2) was measured in media via ELISA. Matrix ...
Lavado RA, Lewis J, Montgomery JB.Laminitis is a severely debilitating and life-threatening condition that occurs as a consequence of different primary triggering factors. Continuous digital hypothermia (CDH) is recommended in horses at risk of, or diagnosed with, acute laminitis due to its several physiological and biochemical alterations that may be positive for the prevention and early treatment of the condition, representing a low risk of adverse effects. Modulation of the inflammatory response, profound vasoconstriction, and prevention of tissue damage are the most notable protective effects of cryotherapy on the lamellae...
Pielok A, Kępska M, Steczkiewicz Z, Grobosz S, Bourebaba L, Marycz K.Medicinal signaling cells (MSC) exhibit distinct molecular signatures and biological abilities, depending on the type of tissue they originate from. Recently, we isolated and described a new population of stem cells residing in the coronary corium, equine hoof progenitor cells (HPCs), which could be a new promising cell pool for the treatment of laminitis. Therefore, this study aimed to compare native populations of HPCs to well-established adipose-derived stem cells (ASCs) in standard culture conditions and in a pro-inflammatory milieu to mimic a laminitis condition. ASCs and HPCs were either...
Ribeiro Neto LM, Salvadori MC, Spinosa HS.Due to the widespread use of dexamethasone in racing horses, mostly in low doses by intra-articular administration for the treatment of inflammatory processes, a method is developed to detect this drug in horse urine samples using liquid-liquid extraction followed by immunoaffinity chromatography. Liquid chromatography with diode-array detection is used for the identification of the drug. The use of immunoaffinity columns enhances the selectivity of the analysis, and the results show that dexamethasone can be detected up to 28 h after intra-articular administration.
Heinrich B.This research article corrects a common misconception about the energy metabolism in horses during short sprinting and long-distance running events, emphasizing that short sprints are primarily powered by anaerobic activity, […]
Trsan J, Nottle BF, Pusterla N.This study was designed to determine the effect of PPG and/or flunixin meglumine on SAA response when used at clinical dosing regimens in healthy adult horses. Six healthy adult horses were enrolled in a crossover study design including one control and three treatment groups: no treatment (control); PPG alone (intramuscularly q12h for 72h); flunixin meglumine alone (intravenously q24h for 72h); and PPG (intramuscularly q12h for 72h) and flunixin meglumine (intravenously q24h for 72h). Whole blood was collected at 0, 24, 48, 72, 96 and 120 hours post-initial drug administration to measure SAA u...
Tallon RE, Gough RL, McGovern KF.To describe the use of an equine compression suit to manage a deep axillary wound in a Thoroughbred filly with bilateral pneumothorax. Methods: A 2-year-old Thoroughbred filly was referred for management of a deep wound to the left axilla. Packing and bandaging of the area were initially attempted, but this became repeatedly dislodged, and bandaging was discontinued. The filly subsequently developed widespread subcutaneous emphysema, and the wound was slow to granulate. Acute onset respiratory distress occurred 11 days after admission, secondary to bilateral worsening pneumothorax, and requir...
Elder E, Wong D, Johnson K, Robertson H, Marner M, Dembek K.Bacterial sepsis is the leading cause of death in foals and is associated with hypothalamic-pituitary-adrenocortical axis (HPAA) dysfunction. HPAA function can be evaluated by an arginine-vasopressin (AVP) stimulation test. Objective: Administration of AVP will stimulate a dose-dependent rise in systemic adrenocorticotropin-releasing hormone (ACTH) and cortisol in neonatal foals. There will be no response seen in corticotropin-releasing hormone (CRH) and baseline AVP will be within reference interval. Methods: Twelve neonatal foals, <72 hours old. Methods: HPAA function was assessed in foals...
Carroll EJ, Lasmanis J, Schalm OW.A method is described for production of an equine anti-bovine leukocyte serum (EABLS). Leukocytes were harvested from the milk of cow's udders which had been irritated with endotoxin. The washed leukocytes as antigens were administered to 2 horses in a series of subcutaneous and intravenous injections. There was a variably progressive increase in total serum proteins and a decrease in albumin/blobulin ratios, but the most pronounced change was an increase in beta2-globulins. Accompanying these changes was an increase in the number of precipitin lines as shown by Ouchterlony analysis. Four old ...
Ettlinger JJ, Ford T, Palmer JE.Proximal enteritis was diagnosed on the basis of clinical signs of disease in 2 Standard-bred yearlings from the same farm. Large volumes of fluid were repeatedly obtained during gastric decompression. The horses did not respond to treatment with IV administered fluids, antimicrobial agents, cimetidine, and metoclopramide. Postmortem findings confirmed severe focal chronic active duodenitis with stricture formation. An etiologic agent was not identified.