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.
GARDIKAS C, KALLINIKOU M, KALLINIKOS G.The present experiments seem to indicate that horse blood is deficient in both Factors VIII and IX, the concentration of Factor VIII varying from 30 to 60 per cent of the normal human levels, and the concentration of Factor IX varying from 50 to 80 per cent, the corresponding concentrations in 12 normal human males varying from 60 to 150 per cent and from 70 to 150 per cent, respectively.
The finding that the recalcification time of horse plasma was considerably longer than that of normal human plasma is of interest, since it is known that only very low concentrations of Factor VIII or Fact...
ALEXANDER F.No abstract available1. The magnitude of the rhythmic contractions of the perfused ileum varied with the supply of oxygen.
2. Isotonic sodium chloride solution was as good as Tyrode's solution for suspension of the red cells in the perfusion fluid.
3. Variation of the potassium and calcium content of the perfusion fluid had little effect on motility. Sodium ions had a specific function in maintaining motility.
4. The chloride ions in the perfusion fluid were replaced by bromide, phosphate and sulphate ions without affecting motility. Iodide ions were toxic.
5. The ileum perfused wi...
King LS.The behavior of a fixed strain of Eastern equine encephalomyelitis virus was studied in guinea pigs after intraocular inoculation. Such inoculation concerns the central and not the peripheral nervous system. The susceptibility to intraocular injection lies midway between the highly virulent intracerebral and the quite avirulent peripheral routes. The virus must act for 10 to 13 hours in order to induce a fatal infection. Removal of the inoculated eyeball before this interval almost always prevents fatality although it may allow immunity to develop. The virus, at suitable intervals after inject...
Fortin-Trahan R, Lemirre T, Santschi EM, Janes JG, Richard H, Fogarty U, Beauchamp G, Girard CA, Laverty S.There is a knowledge gap about how equine MFC subchondral radiolucencies (SR) arise and evolve. Osteoclasts are believed to have a role but have not been studied in situ. Objective: To measure and compare osteoclast density and the percentage of chondroclasts in healthy and MFC SR specimens from juvenile Thoroughbreds. Methods: Cadaveric study. Methods: Medial femoral condyles (MFC) from a tissue bank of equine stifles were studied. Inclusion criteria were MFCs (≤8 months old) with a computed tomography SR lesion and histological focal failure of endochondral ossification (L group). Contral...
Hunt JM, Edwards GB, Clarke KW.A survey of 259 surgical colic cases revealed that over 50 per cent of fatalities occurred in the postoperative period. Postoperative ileus and circulatory/endotoxaemic shock accounted for 70 per cent of these deaths. Other less important complications were salmonellosis, long bone fracture, adhesions, haemorrhage, laminitis, wound infection and ischaemic muscle damage. Close monitoring of postoperative progress is necessary to enable early diagnosis and treatment. Recent developments in understanding of the pathophysiology of endotoxic shock and ileus may lead to more successful treatment reg...
Steinhardt J, Hiremath CB.Many of the stability characteristics of horse ferrihemo-globin (Hb+) in acid solutions, such as pH dependence and susceptibility to stabilization by iron ligands, are shared by human ferrihemoglobin, but striking differences between the two proteins exist. The most noticeable is the much greater rate of denaturation of the human protein at all pH values. Other differences include a shift to higher pH in the equi-librium between native and acid-denatured forms, differ-ences in the temperature at which the temperature effect on the equilibrium-pH curve reverses, a complete absence in human Hb+ ...
Coomer RPC, Terschuur JA, Pressanto MC, Walker I.To assess the efficacy of commercial intra-articular blood-derived allogeneic-induced mesenchymal stem cells (CIMSCs) to treat tarsometatarsal lameness in horses. Methods: This was a retrospective cohort study. Methods: Records from 167 adult light breed horses with bilateral tarsometatarsal lameness. Methods: Horses with tarsometatarsal lameness were retrospectively selected from medical records. Diagnosis followed subjective graded lameness assessment before and after intra-articular analgesia, with graded radiographic tarsal examination. Horses were excluded if they were diagnosed or treate...
Vitums A, Grant BD, Stone EC, Spencer GR.ABSTRACT Transposition of the aorta to the right ventricle with atresia of the pulmonary trunk was described in a 2 year old horse. Clinical and physiological examinations were performed and data recorded. Teratogenesis of the present anomaly was discussed and the literature reviewed. The probable course of circulation during the fetal life and after birth of this animal was suggested. An extensive col-lateral circulation was developed to the lungs, which might explain how the animal could live so long.
Hare JE, Viel L, Conlon PD, Marshall JS.Pulmonary mast cells (PMC) are important components of the inflammatory process in equine allergic lung diseases such as heaves. Very little, however, is known of the degranulation kinetics of these cells and thus, their pathophysiologic role remains largely speculative. The purpose of this study was to develop a repeatable protocol for in vitro equine PMC degranulation. Five mature horses (sex: 2 M, 3 F; age: 8.8 +/- 6.5 y), historically free of pulmonary disease and normal on clinical respiratory examination, arterial blood gas analysis, pulmonary mechanics testing and histamine inhalation c...
Hashimoto-Hill S, Alenghat T.Domestic animals represent important resources for understanding shared mechanisms underlying complex natural diseases that arise due to both genetic and environmental factors. Intestinal inflammation, particularly inflammatory bowel disease (IBD), is a significant health challenge in humans and domestic animals. While the etiology of IBD is multifactorial, imbalance of symbiotic gut microbiota has been hypothesized to play a central role in disease pathophysiology. Advances in genomic sequencing and analytical pipelines have enabled researchers to decipher the composition of the intestinal mi...
A review of the literature is given concerning the anatomy and pathophysiology of the equine penis with regard to priapism: a prolonged erection of the penis not associated with sexual arousal. Several treatment options, such as flushing of the corpus cavernosum penis with heparinized saline and the creation of shunt between the corpus cavernosum penis and the corpus spongiosum penis are discussed. Subsequently, a case of priapism in a stallion following the injection of acepromazine, is discussed. The priapism resolved after the corpus cavernosum penis was flushed with the stallion under gene...
López JR, Linares N, Cordovez G, Terzic A.Exertional rhabdomyolysis is a myopathy of unknown pathophysiology. We measured intracellular resting calcium concentration ([Ca2+]i) by means of Ca(2+)-selective microelectrodes in intercostal muscle fibers from horses suffering from rhabdomyolysis, and from horses with no evidence of neuromuscular disorder. [Ca2+]i was several-fold higher in muscle fibers from horses suffering from rhabdomyolysis when compared to controls. Treatment of rhabdomyolytic horses with dantrolene, an agent that prevents Ca2+ release from the sarcoplasmic reticulum, reduced [Ca2+]i toward control values, and acceler...
Müller EMT, Vanderperren K, Merle R, Rheinfeld S, Leelamankong P, Lischer CJ, Ehrle A.The objective of this retrospective, observational, controlled study was to evaluate bone and soft tissue window CT images of the proximoplantar metatarsus III region in twenty horses with pain localized to the proximal suspensory ligament (PSL) and 20 horses with findings nonrelated to tarsal pain. All horses underwent CT and radiographic examination. Images were reviewed by three independent observers who graded the severity and localization of findings. Bone-related categories as well as soft tissue-related categories were evaluated. For the comparison of imaging findings in horses with and...
Julien ME, Shih JB, Correa Lopes B, Vallone LV, Suchodolski JS, Pilla R, Scott EM.Next generation sequencing (NGS) studies in healthy equine eyes have shown a more diverse ocular surface microbiota compared to culture-based techniques. This study aimed to compare the bacterial ocular surface microbiota in both eyes of horses with unilateral ulcerative keratitis (UK) with controls free of ocular disease. Conjunctival swabs were obtained from both ulcerated eyes and unaffected eyes of 15 client-owned horses with unilateral UK following informed consent, as well as from one eye of 15 healthy horses. Genomic DNA was extracted from the swabs and sequenced on an Illumina platform...
Asif S, Umar T, Umar Z, Jamil H, Feng H, Zhang P, Umer S.Endometritis plays an important role in mare infertility. Certain infectious agents interfere with the innate immune system of endometrium, causing a systemic inflammatory response that lasts for a long time and circulates via the blood or cellular degeneration, leading to endometritis due to bacterial endotoxins. Different small, non-coding RNA molecules are involved in many biological functions. For instance, microRNAs (miRNAs) are involved in the post-transcriptional regulation of gene expression. These miRNAs are important regulators of gene expression, primarily via inhibiting transcripti...
Lee DF, Everest DJ, Cooley W, Chambers MA.Equine asthma, previously known as Recurrent Airway Obstruction (RAO) or Inflammatory Airway Disease (IAD), is an often-debilitating condition that may severely affect both performance and quality of life. Research is hindered by the low sample numbers of subjects recruited to studies, a consequence in part of the invasive nature of the sampling methods of bronchial brushing and biopsy. We present an alternative method of sampling equine airway epithelial cells, the 'nasal brush method' (NBM). Obtained by light brushing of the ventral meatus whilst the horse is under standing sedation, these c...
Paul LJ, Ericsson AC, Andrews FM, McAdams Z, Keowen ML, St Blanc MP, Banse HE.Equine glandular gastric disease (EGGD) is a common disease among athletic horses that can negatively impact health and performance. The pathophysiology of this EGGD remains poorly understood. Previous studies using controlled populations of horses identified differences in the gastric glandular mucosal microbiome associated with disease. The objective of this study was to compare the gastric microbiome in horses with EGGD and those without across multiple barns and differing management practices. We hypothesized that alterations in the microbiome of the gastric glandular mucosa are associated...
Jeong S, Bond SL, Sole-Guitart A.Dynamic nasopharyngeal collapse (NPC) is an obstructive upper airway disease that affects mainly the inspiratory phase of respiration in horses undergoing strenuous exercise. It occurs when the neuromuscular activity of the nasopharynx is overwhelmed by the intense negative pressures generated during exercise. This leads to collapse of at least one of the four components of the nasopharynx which is comprised of the two lateral walls, the dorsal roof and the ventral soft palate. As a result, the airway diameter and thus airflow become compromised. Even small changes in the airway diameter produ...
Degroote RL, Schmalen A, Hauck SM, Deeg CA.The perception of circulating granulocytes as cells with a predetermined immune response mainly triggered by pathogens is evolving, recognizing their functional heterogeneity and adaptability, particularly within the neutrophil subset. The involvement of these cells in the pathophysiology of autoimmune uveitis has become increasingly clear, yet their exact role remains elusive. We used an equine model for autoimmune-mediated recurrent pan-uveitis to investigate early responses of granulocytes in different inflammatory environments. For this purpose, we performed differential proteomics on gran...
Carslake HB, Pinchbeck GL, Argo CM, Dugdale AHA, McGowan CM.Glucagon-like peptide-1 (GLP-1), the principal incretin in horses, may play a role in the pathophysiology of insulin dysregulation (ID). This study aimed to describe its concentration in response to three preserved forages and four dynamic tests for ID in ponies. Twelve adult ponies of mixed ID status were given a meal of hay, soaked hay or haylage, an in-feed oral glucose test (OGT), oral sugar test (OST), an oral test using a proprietary breakfast cereal (WEET) or a combined glucose-insulin tolerance test (CGIT) weekly in a randomised cross-over study. Glucose, insulin and GLP-1 concentratio...
Al-Modhefer AK, Atherton JC, Garland HO, Singh HJ, Walker J.Single-nephron and whole-kidney function were studied in female rats with corticomedullary nephrocalcinosis, and in animals where the lesion had been prevented either by a dietary magnesium supplement or by using a diet with a calcium:phosphorus ratio in excess of 1. At the single-nephron level, rats with nephrocalcinosis had prolonged tubular fluid transit times. Proximal transit time was 19.42 +/- 1.98 (mean +/- S.E. of mean) vs. 11.58 +/- 0.19 s for controls; distal transit time was 62.64 +/- 9.16 vs. 31.50 +/- 1.03 s for controls. Although single-nephron function is altered in nephrocalcin...
Machado M, Camacho AL, Coubrough C, R R Queiroz-Machado C, Custodio C, Barros CSL, Riet-Correa F, Menchaca A.We reported thirteen cases of bilateral stringhalt associated with Hypochaeris radicata that occurred in horses in Uruguay during a severe drought in the summer of 2023. All horses were affected chronically and progressively by bilateral hyperflexion of hindlimbs. In two severely affected horses, the main histological lesions included neuronal chromatolysis and axonal spheroids in the ventral gray horn in the lumbar and sacral spinal cord and axonal degeneration and digestion chambers in ventral roots fibers and long peripheral nerves. We suggest that in addition to injuries to peripheral nerv...
Shawaf T.Exercise-induced pulmonary hemorrhage (EIPH) is one of the most commonly diagnosed disorders in racehorses. Many EIPH risk factors such as breed, age, high or low environmental temperature, and distance of the race have been studied in racehorses. Unassigned: The aim of this study was to study the relationship between EIPH and the presence of jugular vein thrombose in racehorses. Unassigned: Forty-eight thoroughbred racehorses randomly selected from animals with exercise intolerance due to respiratory disorders were enrolled in the present study. Clinical and tracheobronchoscopy examinations w...
Carvalho Serena G, Marchezan Piva M, Viezzer Bianchi M, Fernandes da Fonseca HC, Chitolina Pupin R, Martins Basso R, Secorun Borges A....In horses, systemic calcinosis is a rare syndrome characterised by muscle lesion associated with the mineralisation of large muscle groups or other organs, in the absence of an alternative cause for the calcification, such as toxic, enzootic or metabolic. Molecular and histopathological aspects of the disease are still poorly elucidated. Objective: To describe the epidemiological, pathological and molecular aspects of systemic calcinosis in a convenience sample of six horses submitted to necropsy in the Southern and Midwestern regions of Brazil. Methods: Retrospective exploratory study. Method...
Fletcher KA, Padalino B, Felici M, Bigi D, Limon-Vega G, Grist A, Gibson TJ.There is limited research into horse slaughter, particularly ante mortem welfare, and the effectiveness of captive-bolt gun (CBG) stunning, despite this being a widely used method worldwide. To address this evidence gap and explore associations between ante and post mortem factors, the welfare of 62 horses was assessed at a commercial Italian abattoir. Animal-based measures were used to identify stress-related behaviours and stunning effectiveness. A sub-sample (44%; 27/62) of heads were assessed for gross brain pathology. All animals in the study showed stress-related behaviours at all stage...
Thompson AJ, Swash M, Cox EL, Ingram DA, Gray A, Schwartz MS.In a woman with a slowly progressive adult onset proximal myopathy, muscle biopsy showed storage of PAS positive material in type 1 fibers. This material consisted of a branched chain polysaccharide associated with a mucoprotein. No abnormality of glycogen-pathway enzymes was detected. This suggested that this polysaccharide accumulation occurred because the polysaccharide was laid down in a non-bioavailable form. The clinical and histochemical features in this patient and in the few similar reported cases indicate that polysaccharide storage myopathy is a distinct entity that is allied to the...
Durward-Akhurst SA, Valberg SJ.Several inflammatory myopathies have an infectious or immune-mediated basis in the horse. Myosin heavy chain myopathy is caused by a codominant missense variant in MYH1 and has 3 clinical presentations: immune-mediated myositis, calciphylaxis, and nonexertional rhabdomyolysis in Quarter Horse-related breeds. An infarctive form of purpura hemorrhagica affects numerous breeds, presenting with focal firm, painful muscle swelling, and subsequent infarction of multiple tissues. While Streptococcus equi equi is often the inciting cause, anaplasmosis, sarcocystis, piroplasmosis, viruses, and vaccines...
Wong D, Sahoo DK, Faivre C, Kopper J, Dersh K, Beachler T, Esser M.Oxidative injury occurs in septic people, but the role of oxidative stress and antioxidants has rarely been evaluated in foals. Objective: To measure reactive oxygen species (ROS), biomarkers of oxidative injury, and antioxidants in neonatal foals. We hypothesized that ill foals would have higher blood concentrations of ROS and biomarkers of oxidative injury and lower concentrations of antioxidants compared to healthy foals. Methods: Seventy-two hospitalized and 21 healthy neonatal foals. Methods: Prospective cohort study. Reactive oxygen species (hydrogen peroxide [HO]), biomarkers of oxidati...
Primo ALM, Assis DM, Santos VGS, de Melo LRB, da Nóbrega LD, Medeiros Dantas AF, Maciel TA.Cerebellar abiotrophy is a neurodegenerative disease that affects the Purkinje cells of the cerebellum, resulting in premature neuronal death. In horses, its occurrence has been reported mainly in the Arabian breed as a congenital mutation inherited in an autosomal recessive manner. The objective of this study was to describe the case of cerebellar abiotrophy in a Quarter Horse foal. An 8-day-old foal was treated after presenting signs of ataxia, hypermetria, difficulty maintaining a standing position, and decreased menace response. The foal was hospitalized for 26 days, received treatment wit...
Hansen S, Hopster-Iversen C, Berg L, Fjeldborg J, Massey C, Piercy RJ, Carstensen H.Exertional myopathies are recognised as a cause of poor performance in equines. In Icelandic horses presenting reduced performance and/or multi-limb lameness, no specific myopathy has been identified. Objective: To characterise the clinical presentation and histopathological findings in muscle biopsy samples from Icelandic horses demonstrating poor performance. Methods: Case series. Methods: Phenotypic characteristics, clinical examination and diagnoses of 17 Icelandic horses were studied. All horses had a resting serum creatine kinase (CK) and aspartate transaminase activities measured, and C...
Gómez-Torres F, Ballesteros-Acuña L, Ruíz-Sauri A.Arrhythmic sudden cardiac death in dogs and horses often results from ventricular arrhythmia secondary to myocardial damage. Despite this, limited data exist on the histomorphometric changes in cardiac conduction fibers (CCFs) and cardiac conduction cells (CCCs) following spontaneous myocardial infarction (MI). This study aimed to characterize morphometric and histological alterations in conduction fibers and their junctions with cardiomyocytes in infarcted hearts of horses and dogs. Unassigned: Ten hearts from horses and 10 from dogs that had died suddenly were examined. Histological and immu...
Zamith Cunha R, Gobbo F, Morini M, Zannoni A, Mainardi C, D'arpe L, Gramenzi A, Chiocchetti R.A growing body of evidence indicates that the endocannabinoid system (ECS) is essential for controlling the homeostasis of the skin and that the ECS is modified in the presence of skin disease. It is plausible to expect that the lamellar junction of the hoof expresses cannabinoid receptors and that their expression could be affected by lamellar disease. The goal of this study was to characterise the cannabinoid receptor type 1 (CB1R) and type 2 (CB2R) and the G protein-coupled receptor 55 (GPR55) within the dermo-epidermal junction of the hooves of healthy and laminitic horses. The expression ...
