Pathophysiology in horses involves the study of functional changes that occur in the body as a result of disease or injury. This field examines the mechanisms through which diseases develop and progress, as well as how they affect the body's normal physiological processes. In equine research, pathophysiology encompasses a wide range of conditions, including respiratory disorders, musculoskeletal injuries, gastrointestinal diseases, and metabolic syndromes. Understanding these processes helps in identifying potential therapeutic targets and developing effective treatment strategies. This page collects peer-reviewed research studies and scholarly articles that explore the underlying mechanisms, clinical manifestations, and implications of various pathophysiological conditions in equine health.
Platt H, Whitwell KE.A form of generalized fat necrosis and steatitis occurs in pony and donkey foals. The clinical and pathological features of this disorder are described and its possible relationship to a similar condition in the Thoroughbred foal, and to yellow Fat Disease in other species, is discussed.
Priester WA, Glass AG, Waggoner NS.A mass survey of the distribution of congenital defects in various types of livestock was made possible by the processing by the Veterinary Medical Data Program (VMPD) of standard observations collected on 137, 717 patients seen at veterinary college clinics between Mar. 1964 and Jan. 1969. A total of 6455 animals with 1 or more congenital defects was found. The data were analysed according to species, institution and organ system. Pigs had the highest proportion of congenital defects, cats the lowest. Over all, the systems most frequently involved were the musculo-skeletal and urogenital. The...
Hilbert BJ, Rowley G, Antonas KN, McGill CA, Reynoldson JA, Hawkins CD.Sodium hyaluronate was injected into normal horse joints and joints that had undergone an arthrotomy and experimental cartilage damage. The elimination half-life for hyaluronic acid in normal joints was found to be approximately 96 h. The injection caused a non-significant increase (42%) in synovial fluid protein concentration and a fall in the intrinsic viscosity of the fluid. In the arthrotomy group the synovial fluid hyaluronic acid concentration fell after surgery but it was unaffected by the injection of sodium hyaluronate. An initial rise in the intrinsic viscosity of the synovial fluid ...
Leise BS, Fugler LA.Sepsis or systemic inflammatory response syndrome (SIRS) -associated laminitis is a sequela to primary inflammatory conditions (eg, colitis, ischemic intestinal injury, pneumonia, metritis) and results from a dysregulated systemic inflammatory response that ultimately affects the digital lamellae. Local chemokine production, leukocyte migration, and proinflammatory mediator production occur within the lamellae that can lead to catastrophic lamellar failure. Controlling the primary disease, providing supportive care and anti-inflammatory therapy, applying digital cryotherapy, and providing mech...
Gussekloo SW, Lankester J, Kersten W, Back W.To determine the effect of differences in structural and mechanical tendon properties on functionality of the passive stay apparatus in horses. Methods: 5 forelimbs each from nondwarf Friesians, dwarf Friesians, and ponies. Methods: Harvested forelimbs were loaded to test the passive stay apparatus. Tendons that stabilize the distal portion of the limb (superficial digital flexor tendon, deep digital flexor tendon, and tendo interosseus [suspensory ligament]) were isolated, and force-elongation data were obtained. Bone lengths, initial tendon lengths, and initial tendon cross-sectional areas w...
Brown CM.This article reviews the etiology, clinical findings, and significance of diseases of the heart valves, myocardium, pericardium, and great vessels of the horse. Each valve is considered separately from the point of view of murmur production. In addition, the role of the cardiovascular system in the etiology of sudden and unexpected death is considered.
Blikslager A, Gonzalez L.The equine intestinal mucosa is intimately involved in maintaining homeostasis both on a systemic level by controlling extracellular fluid movement and at the local level to maintain barrier function. Horses are particularly susceptible to the clinical syndrome of colic, with the most severe cases involving strangulating obstruction that induces ischemia. Because of the mucosal vascular architecture, the mucosal epithelium is particularly susceptible to ischemic injury. The potential for reperfusion injury has been investigated and found to play a minimal role. However, inflammation does affec...
The development of a nodule is a fairly common reaction pattern in the skin and subcutaneous tissues of the horse. In many such nodules, the inciting aetiologic agent or antigen is unknown, but in some equine cases there is significant evidence for insect bite origin. The pathogenesis of some equine nodular diseases appears to involve marked collagen degeneration which varies from hyalinization to lysis and can become mineralized. The exact role the lytic collagen has in the pathogenesis of these lesions is still unknown. Vascular changes may be present in some entities. Other nodules may be c...
van den Boom R, Wilmink JM, O'Kane S, Wood J, Ferguson MW.Wound healing in horses is often complicated by wound infection, exuberant granulation tissue, and hypertrophic scars, especially when wounds are located on the limbs. Wound healing in ponies is less problematic, characterized by a greater degree of wound contraction and a more intense initial inflammatory response. Because both processes are influenced by transforming growth factor-beta (TGF-beta), it was hypothesized that the better wound healing in ponies was associated with different TGF-beta profiles. A series of small wounds was created on the distal limbs and hindquarters of ponies and ...
Benamou AE, Art T, Marlin DJ, Roberts CA, Lekeux P.Chronic obstructive pulmonary disease (COPD) represents a major cause of loss of performance in the horse. The role of endothelin (ET), a potent bronchoconstrictive and vasoactive peptide, is currently being investigated in asthma and other obstructive respiratory diseases in man. We have previously found elevated systemic and pulmonary endothelin levels in horses during exacerbation of COPD. In the present study, our aim was to examine possible variations in ET concentrations occurring during exercise in COPD horses. We compared the effects of intense treadmill exercise on the recovery of end...
Cummings JF, de Lahunta A, Mohammed HO, Divers TJ, Summers BA, Valentine BA, Jackson CA.Two spontaneous neurodegenerative diseases of the horse, equine motor neuron disease (EMND) and equine degenerative myeloencephalopathy (EDM), have been associated with alpha-tocopherol deficiency, and both were characterized by prominent accumulations of endothelial lipopigment in the small vessels of the spinal cord. These endothelial pigment deposits appear to be reversible. In EMND horses pasture-supplemented for 9 months or more after the progression of weakness and wasting had arrested, there was very little endothelial lipopigment. The origin and the potential effects of these endotheli...
Rugh KS, Ross CR, Sarazan RD, Boatwright RB, Williams DO, Garner HE, Griggs DM.We evaluated the loss of coronary collateral function in the absence of stimulation (disuse inhibition) by doubling the interval between successive left anterior descending coronary artery (LAD) occlusions in ponies in which collateral function initially had been enhanced by 2-min occlusions at 30-min intervals. Before collateralization, occlusion caused segment systolic shortening, velocity of shortening, and stroke work index in the LAD-dependent left ventricular apex to decrease, whereas heart rate and left ventricular end-diastolic pressure increased. After 476 +/- 102 occlusions, segment ...
Teti G, Mazzotti E, Gatta V, Chiarini F, Alfieri ML, Falconi M.Osteoarthritis (OA) is described as a chronic degenerative disease characterized by the loss of articular cartilage. Senescence is a natural cellular response to stressors. Beneficial in certain conditions, the accumulation of senescent cells has been implicated in the pathophysiology of many diseases associated with aging. Recently, it has been demonstrated that mesenchymal stem/stromal cells isolated from OA patients contain many senescent cells that inhibit cartilage regeneration. However, the link between cellular senescence in MSCs and OA progression is still debated. In this study, we ai...
Whitlock D, Garcia TC, Vallance SA, Stover SM.The specific biomechanical circumstances that induce excessive superficial digital flexor tendon (SDFT) strain in horses are unknown. Objective: Carpal joint hyperextension during axial limb loading during the middle of stance disproportionately enhances SDFT strains compared to suspensory ligament (SL) strains. Methods: Superficial digital flexor tendon and SL strains were measured in 7 cadaver limbs during in vitro loading that maintained carpal extension or allowed carpal hyperextension by constraining, or allowing rotation of, the radius during loading conditions that simulated the middle ...
Gulick BA, Liu IK, Qualls CW, Gribble DH, Rogers QR.Plasma amino acid patterns were studied in 6 clinically normal adult horses during the course of hepatic disease induced by feeding them plants containing pyrrolizidine alkaloids. At death, there were significant (P less than 0.01) increases in glutamine, proline, tyrosine, asparagine, lysine, histidine, alanine, phenylalanine, methionine, aspartic acid, and ornithine values. There were no significant changes in glycine, valine, isoleucine tryptophan, and arginine values. There were significant (P less than 0.01) decreases in citrulline. Ammonia increased 4-fold. Alpha-Aminoadipic acid and alp...
Blangy-Letheule A, Vergnaud A, Dupas T, Rozec B, Lauzier B, Leroux AA.Sepsis is a life-threatening disease defined as an organ dysfunction caused by a dysregulated host response to an infection. Early diagnosis and prognosis of sepsis are necessary for specific and timely treatment. However, no predictive biomarkers or therapeutic targets are available yet, mainly due to the lack of a pertinent model. A better understanding of the pathophysiological mechanisms associated with sepsis will allow for earlier and more appropriate management. For this purpose, experimental models of sepsis have been set up to decipher the progression and pathophysiology of human seps...
Borer-Weir KE, Bailey SR, Harris PA, Menzies-Gow NJ, Elliott J.Digital vasoconstriction, ischaemia and hypoxia may predispose to acute laminitis. Laminitis incidence varies seasonally, peaking in spring and summer. Direct seasonal influences on equine digital artery (EDA) contractility have not been investigated. This study assessed seasonal variation in maintenance of phenylephrine (PHE)-induced tone in isolated EDAs under hypoxic (95% nitrogen) and hyperoxic (95% oxygen) conditions. The objective was to measure change in arterial tone over time after constriction to a plateau with PHE. Tone was measured at plateau and over time and percentage change cal...
Moore RM, Venugopalan CS, Sedrish SA, Holmes EP.To determine in vitro contractile responses of equine colonic veins to various vasoconstrictor agents. Methods: Colonic veins collected from 8 adult horses. Methods: Veins were cut into 4-mm-wide rings, placed in organ baths at 37 C, and attached to a force-transducer interfaced with a polygraph; 2 g of tension was applied, and rings were allowed to equilibrate for 45 minutes. Bath solution was replaced, and tension was reapplied at 15-minute intervals. Cumulative concentration responses (10(-8) to 10(-4) M) were determined for each agent, using separate rings (n = 8). Three vein groups were e...
Kajabi AW, Casula V, Sarin JK, Ketola JH, Nykänen O, Te Moller NCR, Mancini IAD, Visser J, Brommer H, René van Weeren P, Malda J, Töyräs J....Chondral lesions lead to degenerative changes in the surrounding cartilage tissue, increasing the risk of developing post-traumatic osteoarthritis (PTOA). This study aimed to investigate the feasibility of quantitative magnetic resonance imaging (qMRI) for evaluation of articular cartilage in PTOA. Articular explants containing surgically induced and repaired chondral lesions were obtained from the stifle joints of seven Shetland ponies (14 samples). Three age-matched nonoperated ponies served as controls (six samples). The samples were imaged at 9.4 T. The measured qMRI parameters included ...
Ruby RE, Janes JG.The variety of neurologic diseases which affect horses makes pathologic examination of the nervous system a complex and lengthy process. An understanding of the common causes of neurologic disease, antemortem neurolocalization, and supplementation of the necropsy examination with ancillary testing will help to diagnose a large number of causes of neurologic disease. A general understanding of neuropathology and collaborative relationship with your local pathologists will aid in the definitive diagnosis of neurologic diseases.
Crawford AM, Mills JN.Venoms of the tiger snake and brown snake were procoagulant, in vitro, when tested with cat, dog, horse and wallaby plasma. In the absence of calcium and phospholipid the coagulant activity of tiger snake venom was minimal. In contrast, brown snake venom alone had marked procoagulant activity. This activity, however, was enhanced by the presence of calcium and phospholipid. Death adder venom exerted an anticoagulant effect. Apparent species' differences in susceptibility to the coagulant venoms were noted. However, the probable explanation of these differences was attributed to variation in th...
Luo J, Wang Z, Tang C, Yin Z, Huang J, Ruan D, Fei Y, Wang C, Mo X, Li J, Zhang J, Fang C, Li J, Chen X, Shen W.Tendinopathy is a common motor system disease that leads to pain and reduced function. Despite its prevalence, our mechanistic understanding is incomplete, leading to limited efficacy of treatment options. Animal models contribute significantly to our understanding of tendinopathy and some therapeutic options. However, the inadequacies of animal models are also evident, largely due to differences in anatomical structure and the complexity of human tendinopathy. Different animal models reproduce different aspects of human tendinopathy and are therefore suitable for different scenarios. This rev...
Frolov VA, Derx H, Riguer P.Guinea pigs were sensitized by three subcutaneous injections of 0.1 ml native horse serum at 2-day intervals, 21 days after the third injection the animals developed marked sensitization to this antigen which was manifested by anaphylactic reaction to the subcutaneous challenge with this antigen. At this time, the myocardium of the sensitized animals showed signs of extra- and intracellular oedema, a sharp increase in the number of lysosomes, damage of their membranes, 2 1/2 months after sensitization the animals showed no anaphylactic reaction to the challenge dose of the antigen. There were ...
Abraham G.This review provides an overview of the early and current literature including contributions that highlight the parasympathetic cholinergic receptor systems in domestic animal tissues. Muscarinic acetylcholine receptors (mAChRs) belong to the subfamily of G protein-coupled receptors and regulate many fundamental functions of the central and peripheral nervous systems and have been subject to research over at least 40 years. Nonetheless, there are few studies specifying mAChRs in domestic animal tissues. This review focuses on the pharmacology of muscarinic acetylcholine receptor (mAChR) system...
Pavone S, Veronesi F, Piergili Fioretti D, Mandara MT.Gastrointestinal motility disorders represent a significant cause of morbidity and mortality in horses. Previously regarded as a non-pathogenic tapeworm, Anoplocephala perfoliata has been recently associated with equine colic. In this study, pathological changes related to A. perfoliata at the ileocecal junction were investigated in 31 slaughtered horses. Our results showed a significant relationship between parasitic burden and grading of histopathological lesions in both the mucosa and submucosa. Moreover, in infested horses, hypertrophy of the circular muscle layer was determined. Finally, ...
Meijler FL, van der Tweel I.Atrial fibrillation is one of the most common cardiac arrhythmias in humans. It also occurs quite frequently in dogs and horses. Comparative study of this arrhythmia may contribute to better understanding of the pathophysiological mechanisms involved. In this study, we present a quantitative analysis of atrial fibrillation in humans, dogs, horses, and in a kangaroo, making use of histograms and serial autocorrelograms of the ventricular rhythm with and without digitalis medication. Increase in the size of the animal and thus in the size of the heart is accompanied by a decrease in ventricular ...
Cockerell GL, MacCoy DM.This report provides a general overview of the pathobiology of neoplasia, and an update on the clinicopathological manifestations of lymphosarcoma, mastocytoma, histiocytoma, melanoma, sarcoid and circumanal gland tumors in domestic animals. Neoplasia represents a continuum of events from reversible hyperplasia to irreversible and pathological changes in tissue growth patterns. In some instances the causes of this disease process have been identified, but the etiology of the majority of naturally occurring neoplasms remain unknown. Surgical excision is the preferred treatment for tumors, but i...
Sundra T, Gough S, Rossi G, Kelty E, Rendle D.Oral omeprazole is the accepted treatment for equine squamous gastric disease (ESGD); however, it is not universally effective. Esomeprazole results in more consistent and pronounced acid suppression in men and is more effective than omeprazole in the treatment of oesophageal and gastric disease. Pharmacodynamic and pilot clinical studies have indicated esomeprazole might also be more effective than omeprazole in horses. Objective: To compare the efficacy and safety of oral esomeprazole and omeprazole pastes in the treatment of ESGD and, where present, concurrent equine glandular gastric disea...
Norton NM, Santschi E, Fischer KJ.The etiology of subchondral bone cysts (SBCs) is not fully understood. Mechanical trauma and fluid pressure are two mechanisms believed to cause their formation and growth. The equine stifle joint provides a natural animal model for studying SBCs. Computed tomography images of an extended yearling cadaveric stifle joint were segmented using ScanIP to isolate bones and relevant soft tissues. Three model geometries were created to simulate cyst sizes of approximately 0.03 cm (C1), 0.5 cm (C2), and 1 cm (C3). A uniform pressure resulting in 3000 N force was applied at the proximal end of the fem...
Hennemann S, de Abreu MR.Degenerative lumbar spinal stenosis is the most frequent cause of low back pain and/or sciatica in the elderly patient. Epidemiology, pathophysiology, clinical manifestations and testing are reviewed in a wide current bibliographic investigation. The importance of the relationship between clinical presentation and imaging study, especially magnetic resonance imaging (MRI), is emphasized. Prior to treatment indication, it is necessary to identify the precise location of pain, as well as the differential diagnosis between neurological and vascular lameness. Conservative treatment combining medic...
Han SW, Cho YK, Rim JM, Kang JG, Choi KS, Chae JS. Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic tick-borne disease in East Asia caused by the SFTS virus (SFTSV). It is to investigate the presence of SFTSV RNA and antibodies in horses from a slaughterhouse and equestrian centers in the Republic of Korea (ROK). A prevalence study of SFTSV-specific RNA and antibodies was designed from 889 horses in the ROK. Serum samples were collected from horses at a slaughterhouse and equestrian centers from 2018 to 2020. To detect the presence of SFTSV, RNA was extracted from the serum samples, and a nested reverse transcriptio...
Heffron CJ, Baker GJ.Fibreoptic endoscopy was used to study the movements of the larynx and pharynx during nasal occlusion in 10 horses, which showed signs consistent with functional pharyngeal obstruction (FPO) on exercise. Cine-endoscopic films were made on 3 such horses. Consideration of the anatomy of the region indicates that FPO may best be regarded as a subluxation of the nasopharyngeal and larygneal airways and it was found that a constant component of the movements which brought about this subluxation was a marked caudal retraction of the larynx. It is suggested that this caudal retraction of the larynx o...
