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.
Pliszczak-Król A, Gemra M, Kozdrowski R, Zalewski D, Iwaszko A.Recurrent Airway Obstruction (RAO), also called severe asthma or heaves, is a chronic disease in adult horses caused by aeroallergens from straw or hay. Disturbances in hemostasis (intensified coagulation and depressed fibrinolysis) are considered one of the prominent reasons of inflammatory process, injury and dysfunction of the lungs. The aim of the study was to evaluate chosen parameters of hemostasis in horses with active form of RAO. Ten RAO-horses (group R) and ten healthy horses (group C) were exposed to straw and hay allergen challenge. The prothrombin time (PT), activated partial thro...
Hulliger MF, Pacholewska A, Vargas A, Lavoie JP, Leeb T, Gerber V, Jagannathan V.Severe equine asthma is an incurable obstructive respiratory condition affecting 10-15% of horses in temperate climates. Upon exposure to airborne antigens from hay feeding, affected horses show neutrophilic airway inflammation and bronchoconstriction, leading to increased respiratory effort. The resulting implications range from welfare concerns to economic impacts on equestrian sports and horse breeding. Immunological and pathophysiological characteristics of severe equine asthma show important parallels with allergic and severe neutrophilic human asthma. Our study aimed at investigating reg...
Fortin JS, Benskey MJ, Lookingland KJ, Patterson JS, Howey EB, Goudreau JL, Schott HC.Pituitary pars intermedia dysfunction (PPID) develops slowly in aged horses as degeneration of hypothalamic dopaminergic neurons leads to proliferation of pars intermedia (PI) melanotropes through hyperplasia and adenoma formation. Dopamine (DA) concentrations and tyrosine hydroxylase (TH) immunoreactivity are markedly reduced in PI tissue of PPID-affected equids and treatment with the DA receptor agonist pergolide results in notable clinical improvement. Thus, we hypothesized that pergolide treatment of PPID-affected horses would result in greater DA and TH levels in PI tissue collected from ...
Rabba S, Petrucci V, Petrizzi L, Giommi DW, Busoni V.Information concerning B-mode ultrasonographic abnormalities and power Doppler (PD) signal in suspensory ligament branches of nonlame working Quarter Horses are not reported. The aims of this study were to investigate the prevalence of B-mode ultrasonographic abnormalities and PD signal in suspensory ligament branches in a group of nonlame working Quarter Horses and to compare B-mode findings with PD findings of horses in two different training (barrel racing and team roping). Twenty-one Quarter Horses in training, 14 barrel racing (Group B) and seven team roping horses (Group R), were assesse...
Kutasi O, Fehér O, Sárdi S, Balogh N, Nagy A, Moravszki L, Bódai E, Szenci O.West Nile virus (WNV) is a zoonotic arbovirus transmitted by mosquitoes between wild birds (natural hosts) and other vertebrates. Horses and humans are incidental, dead-end hosts, but can develop severe neurological disorders. Owing to the close contact of cerebrospinal fluid (CSF) with the extracellular fluid of the brain, the analysis of CSF composition can reflect central nervous system (CNS) impairments enabling the diagnosis and understanding of various neurodegenerative CNS disorders. Our objective was to compare the findings from the CSF samples of horses with neuroinvasive WNV infectio...
Günay Uçmak Z, Kurban I, Uçmak M.Endometritis is a major cause of infertility in mares. The aim of this study is to evaluate the preovulatory follicle (POF) vascularization (A mix, A red, A blue), POF diameter, POF wall thickness, and uterine diameters in mares with or without endometritis. Ten healthy mares and 10 mares with endometritis diagnosed by the combination of transrectal palpation, ultrasonographic examination, and cytology brush were enrolled in the study. Data of the groups obtained at 2 days before the ovulation (day -2) were compared with Student's t-test. Correlations of the parameters were determined by the ...
Couetil L, Cardwell JM, Leguillette R, Mazan M, Richard E, Bienzle D, Bullone M, Gerber V, Ivester K, Lavoie JP, Martin J, Moran G, Niedźwiedź A....The 2019 Havemeyer Workshop brought together researchers and clinicians to discuss the latest information on Equine Asthma and provide future research directions. Current clinical and molecular asthma phenotypes and endotypes in humans were discussed and compared to asthma phenotypes in horses. The role of infectious and non-infectious causes of equine asthma, genetic factors and proposed disease pathophysiology were reviewed. Diagnostic limitations were evident by the limited number of tests and biomarkers available to field practitioners. The participants emphasized the need for more accessi...
Chan G, Morgan WH, Yu DY, Balaratnasingam C.Astrocytes are critical for the maintenance of retinal ganglion cell (RGC) axonal function and viability, and form a key component of the functional neurovascular unit. Recently, we described the quantitative properties of astrocytes in relation to the capillary distributions in optic nerve laminar regions. Here, we provide a quantitative analysis of astrocytes and RGC axons in longitudinal sections of optic nerve tissue. Histological and immunocytochemical techniques are used to demonstrate the density of astrocytes, RGC axons and glia-neuron ratios across the pre laminar, lamina cribrosa and...
Decloedt A, Van Steenkiste G, Vera L, Buhl R, van Loon G.Atrial fibrillation (AF) is the most common clinically relevant arrhythmia in horses, with a reported prevalence up to 2.5%. The pathophysiology has mainly been investigated in experimental animal models and human medicine, with limited studies in horses. Atrial fibrillation results from the interplay between electrical triggers and a susceptible substrate. Triggers consist of atrial premature depolarizations due to altered automaticity or triggered activity, or local (micro)reentry. The arrhythmia is promoted by atrial myocardial ion channel alterations, Ca2+ handling alterations, structural ...
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...
Valberg SJ.There are 5 single-gene mutations that are known to cause muscle disease in horses. These mutations alter the amino acid sequence of proteins involved in cell membrane electrical conduction, muscle energy metabolism, muscle contraction, and immunogenicity. The clinical signs depend on the pathway affected. The likelihood that an animal with a mutation will exhibit clinical signs depends on the mode of inheritance, environmental influences, and interactions with other genes. Selection of a genetic test for use in diagnostic or breeding decisions requires a knowledge of clinical signs, mode of i...
Patterson Rosa L, Mallicote MF, Long MT, Brooks SA.An analogous condition to human metabolic syndrome, Equine Metabolic Syndrome (EMS) is defined by several clinical signs including obesity, hyperinsulinemia, and peripheral insulin dysregulation (ID). Affected horses may also exhibit hypertension, hyperlipemia and systemic inflammation. Measures of ID typically comprise the gold-standard for diagnosis in veterinary care. Yet, the dynamic nature of insulin homeostasis and complex procedures of typical assays make accurate quantification of ID and EMS challenging. This work aimed to investigate new strategies for identification of biochemical ma...
Miller SM.Otobius megnini has been associated with certain clinical conditions in horses in both California and Mexico. A number of cases similar to those described previously have been identified by the author in South Africa. This case report summarises these cases to demonstrate that the clinical condition occurs readily in South Africa and may be increasing in occurrence. The disease has minimal coverage in the literature making it more likely that a veterinarian, unfamiliar with the disease, will miss the diagnosis. The author would like to make veterinarians aware of this as a potential differenti...
Dubuc V, Laverty S, Richard H, Doré M, Theoret C.There is a growing interest in the scientific community to use computer-based software programs for the quantification of cells during physiological and pathophysiological processes. Drawbacks of computer-based methods currently used to quantify immunohistochemical staining are the complexity of use, expense of software and overly-simplified descriptions of protocol thereby limiting reproducibility. The precise role of mast cells in equine cutaneous wound healing is unknown. Given the contribution of mast cells to the chronic inflammation observed in human keloid, a pathology similar to exuber...
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 ...
Han Y, Tang C, Liao Q, Li Z, Deng L.Serum and plasma are commonly used in clinical practice considering the widely accepted fact that the "normal" protein expression pattern of a healthy animal changes under disease conditions. We herein used a label-free mass spectrometry-based quantitative proteomics approach to characterize the serum proteome of donkeys. A total of 277 unique proteins were identified from 2,388 unique peptides. Gene ontology analyses showed that the most frequent processes were related to metabolic activities and biological regulation, response to stimulus, and immune system processes. The main annotated area...
Norton E, McCue ME.A role for a genetic contribution to equine metabolic syndrome (EMS) and pars pituitary intermedia dysfunction (PPID) has been hypothesized. Heritability estimates of EMS biochemical measurements were consistent with moderately to highly heritable traits. Further, genome-wide association analyses have identified hundreds of regions of the genome contributing to EMS and candidate variants have been identified. The genetics of PPID has not yet been proven. Continued research for the specific genetic risk factors for both EMS and PPID is crucial for gaining a better understanding of the pathophys...
Brinkhof S, Te Moller N, Froeling M, Brommer H, van Weeren R, Ito K, Klomp D.T2* mapping is promising for the evaluation of articular cartilage collagen. In this work, a groove model in a large animal is used as a model for posttraumatic arthritis. We hypothesized that T2* mapping could be employed to differentiate between healthy and (subtly) damaged cartilage. Eight carpal joints were obtained from four adult Shetland ponies that had been included in the groove study. In this model, grooves were surgically created on the proximal articular surface of the intermediate carpal bone (radiocarpal joint) and the radial facet of the third carpal bone (middle carpal joint) b...
Mendoza Garcia FJ, Gonzalez-De Cara C, Aguilera-Aguilera R, Buzon-Cuevas A, Perez-Ecija A.Little information is available about endotoxemia in donkeys. Characterizing the systemic inflammatory response (SIRS) to lipopolysaccharide (LPS) in donkeys would provide valuable clinical and therapeutic information. The effects of meloxicam on endotoxemia have not been studied in this species. Objective: To study the pathophysiology and gene expression associated with experimentally induced endotoxemia, and evaluate the effects of meloxicam on experimentally induced endotoxemia in donkeys and in equine monocyte cultures. Methods: Six healthy adult female donkeys. Methods: Endotoxemia was in...
Podstawski P, Witarski W, Szmatoła T, Bugno-Poniewierska M, Ropka-Molik K.Sarcoids are the most common skin neoplasm in the Equidae family. Sarcoids are benign, but may cause severe damage in affected animals. Due to the high risk of post-treatment recurrence and the lack of an effective method of treatment, it is reasonable to perform studies on the molecular aspects of this neoplasm. Therefore, the present studies analyzed five genes (cell cycle control binding protein alpha, coronin 1b, metalloproteinase 2, tissue inhibitor of metalloproteinases 3 and vimentin) related to cell mobility and invasion traits. Primary healthy fibroblasts and sarcoid cells were obtain...
Van Steenkiste G, L V, Decloedt A, Schauvliege S, Boussy T, van Loon G.Understanding the depolarisation pattern of the equine heart under normal physiologic conditions, and its relationship to the surface electrocardiogram (ECG), is of uppermost importance before any further research can be done about the pathophysiology of complex arrhythmias. In the present study, a 3D electro-anatomical mapping system was used to evaluate the qualitative and quantitative depolarisation patterns and correlation to the surface ECG of both the atrial and ventricular endocardium in seven healthy horses in sinus rhythm under general anaesthesia. Bipolar activation maps of the endoc...
Vera L, Van Steenkiste G, Decloedt A, Chiers K, van Loon G.Arterial rupture mainly affects older horses. The reason why older horses are more prone to arterial rupture and which underlying vascular changes predispose older horses to aortic rupture is still unclear. Objective: To investigate the effect of ageing on the equine arterial wall and blood pressure. Methods: Cohort study. Methods: Non-invasive blood pressure measurement using a tail cuff and vascular ultrasound from aorta, common carotid artery and external iliac artery was performed in 50 healthy young (3-7 years) and 50 healthy old Warmblood horses (>18 years). Arterial diameters and c...
Hu K, Stewart AJ, Yuen KY, Hinrichsen S, Dryburgh EL, Bertin FR.Determination of plasma adrenocotrophic hormone (ACTH) concentration (endogenous or thyrotropin-releasing hormone [TRH] stimulation test) is the most commonly used diagnostic test for pituitary pars intermedia dysfunction (PPID) in horses. Because ACTH is unstable, samples often are frozen to be shipped to laboratories or to allow for batch analysis of research samples. However, the effect of multiple freeze-thaw cycles on equine ACTH is unknown. Objective: To determine the effects of multiple freeze-thaw cycles on immunoreactive ACTH concentration. Methods: Twenty-eight horses ranging from 10...
Quigley A, Sekiya M, Garcia-Campos A, Paz-Silva A, Howell A, Williams DJL, Mulcahy G.Fasciola hepatica is a common parasite of livestock in Ireland, causing significant economic losses and affecting animal welfare. A previous abattoir study of 200 horses led to an estimated 9.5 % prevalence of infection in horses slaughtered in Ireland. However, the epidemiology and pathogenic significance of this infection in this species is not well-described. The objectives of this study were to determine the susceptibility of horses to oral challenge infection with F. hepatica metacercariae, and to document the course of the infection along with serological and biochemical response. We att...
Bacci B, Stent AW, Walmsley EA.Lymphoma is the most common intestinal neoplasm in horses, but its clinical-pathological features are poorly characterized. Primary intestinal lymphoma was diagnosed in 20 horses on biopsy samples and further confirmed by postmortem examination in 16 cases. Lymphoma was found in the small intestine in 12 of 20 (60%), in the colon in 5 of 20 (25%), and in both small and large intestines in 3 of 20 (15%) cases. Gross findings included thickening of the intestinal wall (45%), mural nodules or masses (30%), and both thickening and nodules (10%). Cases were classified according to the human World H...
Dini P, Carossino M, Loynachan AT, El-Sheikh Ali H, Wolfsdorf KE, Scoggin KE, Daels P, Ball BA.Hydrallantois is the excessive accumulation of fluid in the allantoic cavities during the last trimester of pregnancy, leading to abdominal wall hernias, cardiovascular shock, abortion, and dystocia. It has been postulated that hydrallantois is associated with structural and/or functional changes in the chorioallantoic membrane. In the present study, we hypothesized that angiogenesis is impaired in the hydrallantoic placenta. Capillary density in the hydrallantoic placenta was evaluated in the chorioallantois via immunohistochemistry for Von Willebrand Factor. Moreover, the expression of angio...
Linz D, Hesselkilde E, Kutieleh R, Jespersen T, Buhl R, Sanders P.Atrial fibrillation is triggered by the pulmonary veins in humans. Although atrial fibrillation is known to occur in other species, the mechanisms of disease in these are not known. Here we present evidence for pulmonary vein triggers in the horse, where 3D HD Grid mapping was undertaken in the conscious state in the absence of fluoroscopy.
Mostafavi E, Esmaeilnejad B, Meysam Abtahi Foroushani S.This study was undertaken to assess the effects of T. equi infection on serum concentrations of some important cytokines including interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and interleukin-1 beta (IL-1β), IL-1α, IL-4, IL-6, IL-8, IL-10, IL-12α, IL-12β, IL-18, as well as total, protein and lipid binding sialic acids (TSA, PBSA and LBSA). Furthermore, any probable relation among the parasitemia, cytokines and sialic acids (SAs) were calculated using Pearson correlation and simple linear regression. Almost 300 draft horses (Kurdish-breed) with age of 3-4 years old from north-...
Taylor BM, Chaffin MK, Hoffmann AR, Edwards JF, Arenas-Gamboa AM.Prolonged exposure to water, known as immersion foot syndrome in humans, is a phenomenon first described in soldiers during World War I and characterized by dermal ischemic necrosis. In this report, we describe the pathologic findings of a condition resembling immersion foot syndrome in 5 horses and 1 donkey with prolonged floodwater exposure during Hurricane Harvey. At necropsy, all animals had dermal defects ventral to a sharply demarcated "water line" along the lateral trunk. In 5 animals, histologic examination revealed moderate to severe perivascular dermatitis with vasculitis and coagula...
Nasisse MP, Nelms S.Ulcerative keratitis is one of the most common vision-threatening diseases of the horse. Successful therapy, however, can be achieved in the majority of cases provided the diagnosis is made early and the treatment is specific for the disease. This article reviews the pathophysiology, clinical signs, and contemporary medical and surgical approaches to bacterial and fungal ulcerative keratitis in the horse.
McEwan Jenkinson D, Elder HY, Bovell DL.Sweating has a variety of functions in mammals including pheromone action, excretion of waste products and maintenance of the skin surface ecosystem. In a small number of mammalian species, which includes humans and the Equidae, it also has an important role in thermoregulation. This review is focused specifically on the thermoregulatory role of sweat in Equidae and the causes of sweating failure (anhidrosis). The first part describes the glandular appearance, sweat composition, and output rates; and considers the latest theories on the glandular control and secretory mechanisms. It is conclud...
Pollitt CC, Visser MB.In acute laminitis, the suspensory apparatus of the distal phalanx fails at the lamellar dermal/epidermal interface. A grading system for the histopathology of laminitis is based on the consistent pattern of histologic changes to the secondary epidermal lamellae, basal cells, and basement membrane that occur as carbohydrate-induced laminitis develops. The actual trigger factors of carbohydrate-induced laminitis remain unidentified.
Valberg SJ, Perumbakkam S, McKenzie EC, Finno CJ.Equine myofibrillar myopathy (MFM) causes exertional muscle pain and is characterized by myofibrillar disarray and ectopic desmin aggregates of unknown origin. To investigate the pathophysiology of MFM, we compared resting and 3 h postexercise transcriptomes of gluteal muscle and the resting skeletal muscle proteome of MFM and control Arabian horses with RNA sequencing and isobaric tags for relative and absolute quantitation analyses. Three hours after exercise, 191 genes were identified as differentially expressed (DE) in MFM vs. control muscle with >1 log fold change (FC) in genes involve...
Muñoz-Prieto A, Contreras-Aguilar MD, Cerón JJ, Ayala I, Martin-Cuervo M, Gonzalez-Sanchez JC, Jacobsen S, Kuleš J, Beletić A, Rubić I, Mrljak V....Changes in the salivary proteome in 12 horses with the two diseases included in equine gastric ulcer syndrome (EGUS), equine glandular gastric disease (EGGD) (n = 6) and equine squamous gastric disease (ESGD) (n = 6), were evaluated using a high-resolution LC-MS/MS analysis of TMT-labelled peptides and compared to 10 healthy control horses. Serum was also analysed for comparative purposes. The comparison between the horses with EGGD and controls showed significant changes in 10 salivary proteins, whereas 36 salivary proteins were differently abundant between ESGD and control groups. The most u...
Morris DD, Moore JN, Crowe N.Over a 24-month period, serum tumor necrosis factor (TNF) activity was determined in 289 horses with colic attributable to gastrointestinal tract disease. Serum TNF activity was quantitated by use of a modified in vitro cytotoxicity bioassay, using WEHI 164 clone-13 murine fibrosarcoma cells. Causes for colic, determined by clinical and laboratory evaluation, exploratory celiotomy, or necropsy included: gastrointestinal tract rupture (GTR); ileal impaction; small intestinal strangulating obstruction (SIO); proximal enteritis (PE); transient small intestinal distention; large-colon displacement...
Muir WW.Pain is a multidimensional sensory phenomenon that has evolved as a protective method for maintaining homeostasis and facilitating tissue repair. Both excitatory and inhibitory physiologic and pathologic mechanisms are involved in its generation and maintenance. Untreated pain and nervous system changes (plasticity) that occur during chronic pain make pain much more difficult or impossible to effectively treat. Therapies directed toward the treatment of pain should be mechanism based and preventative whenever possible. Prospective, randomized clinical trials conducted in horses that suffer fro...
Tung JT, Venta PJ, Caron JP.To determine the effects of recombinant equine IL-1beta and a number of antiinflammatory compounds on the expression and activity of inducible nitric oxide synthase (iNOS) in cultured equine chondrocytes. Methods: RT-PCR methods were used to amplify a portion of the equine iNOS message to prepare an RNA probe. Northern blot analysis was used to quantify the expression of iNOS in first passage cultures of equine articular chondrocytes propagated in the presence or absence of recombinant equine interleukin-1beta (reIL-1beta), dexamethasone (DEX), polysulfated glycosaminoglycan (PSGAG), hyalurona...
van Eps AW, Burns TA.Laminitis is a consequence of primary disease processes elsewhere in the body. The key pathophysiologic events are insulin dysregulation in endocrinopathic laminitis, ischemia in supporting limb laminitis, and inflammation in sepsis-related laminitis. These apparently disparate mechanisms converge to cause lamellar attachment failure through epithelial cell adhesion loss and stretch, possibly mediated by common growth factor signaling pathways. Tissue damage through mechanical distraction, inflammation, pain, and a proliferative epithelial healing response are features of acute laminitis regar...
Bailey SR, Marr CM, Elliott J.A large number of studies have been undertaken in recent years aimed at furthering our understanding of the complex mechanisms underlying the common and debilitating condition of acute laminitis in the horse. Many of these studies have either reinforced or cast doubt on previously held theories on the pathogenesis of this disease, while others have suggested new mechanisms which may play a key role in its development. This review seeks to put the current hypotheses into the context of this recent body of evidence. While a unifying theory may not yet seem to be achievable, this review demonstra...
Ambrisko TD, Schramel J, Hopster K, Kästner S, Moens Y.To examine changes in the distribution of ventilation and regional lung compliances in anaesthetized horses during the alveolar recruitment manoeuvre (ARM). Methods: Experimental study in which a series of treatments were administered in a fixed order on one occasion. Methods: Five adult Warmblood horses. Methods: Animals were anaesthetized (xylazine, midazolam-ketamine, isoflurane), placed in dorsal recumbency and ventilated with 100% oxygen using peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) of 20 cmHO and 0 cmHO, respectively. Thoracic electrical impedance tomo...
Ehrenhofer MC, Deeg CA, Reese S, Liebich HG, Stangassinger M, Kaspers B.Investigations of the pathophysiology of ocular diseases require a detailed knowledge of the microanatomy of the eye. The available information is still inadequate for the equine retina despite the importance of eye diseases in equine medicine. Here we provide a comprehensive analysis of the histologic features of the horse eye as a reference for future studies. Thirty normal eyes of 15 healthy horses were examined immediately after slaughter. The retina of the horse differs considerably in the degree and quantity of neurons and glial elements as well as in vascular patterns compared to the re...
Cehak A, Rohn K, Barton AK, Stadler P, Ohnesorge B.Dynamic nasopharyngeal collapse with upper airway obstruction is an important cause of exercise intolerance in performance horses. Its underlying pathophysiology is not fully understood. We hypothesize that head position affects pharyngeal diameter, and thus head position may be a contributing factor to nasopharyngeal obstruction. Fifteen adult healthy horses were subjected to endoscopy and radiography at rest. The pharyngeal diameter was measured at nine different head and neck positions. The effect of sedation and breathing cycle on the pharyngeal diameter was determined, and the relationshi...
Fenton FH, Cherry EM, Kornreich BG.To perform the first optical mapping studies of equine atrium to assess the spatiotemporal dynamics of atrial fibrillation (AF) and of its termination by quinidine. Methods: Intact, perfused atrial preparations obtained from four horses with normal cardiovascular examinations. Methods: AF was induced by a rapid pacing protocol with or without acetylcholine perfusion, and optical mapping was used to determine spatial dominant frequency distributions, electrical activity maps, and single-pixel optical signals. Following induction of AF, quinidine gluconate was perfused into the preparation and t...
Haussler KK.A thorough knowledge of equine spinal anatomy, biomechanics, and potential pathology is required to understand the principles and theories behind chiropractic and to apply its techniques properly. Chiropractic provides additional diagnostic and therapeutic means that may help equine practitioners to identify and treat the primary cause of lameness or poor performance. Specialized training in the evaluation and treatment of vertebral joint dysfunction and neuromusculoskeletal disorders places chiropractic in the forefront of conservative treatment of spinal-related disorders. Nevertheless, limi...
Klewitz J, Struebing C, Rohn K, Goergens A, Martinsson G, Orgies F, Probst J, Hollinshead F, Bollwein H, Sieme H.Color Doppler sonography has become routine for the evaluation of high-risk pregnancies in human medicine. Previous studies documenting uterine blood flow parameters in the pregnant mare have found a decrease in peripheral blood flow resistance in the first pregnancy weeks and an increase in uterine blood flow, especially in the last trimester of pregnancy. However, these studies involved only a small number of mares. No naturally occurring pregnancy abnormalities occurred that would allow blood flow changes to be retrospectively examined and analyzed. The objective of the present study was to...
Draper ACE, Piercy RJ.Recurrent Laryngeal Neuropathy (RLN) is a highly prevalent and predominantly left-sided, degenerative disorder of the recurrent laryngeal nerves (RLn) of tall horses, that causes inspiratory stridor at exercise because of intrinsic laryngeal muscle paresis. The associated laryngeal dysfunction and exercise intolerance in athletic horses commonly leads to surgical intervention, retirement or euthanasia with associated financial and welfare implications. Despite speculation, there is a lack of consensus and conflicting evidence supporting the primary classification of RLN, as either a distal ("d...
Espinosa G, Plaza A, Schenffeldt A, Alarcón P, Gajardo G, Uberti B, Morán G, Henríquez C.Polymorphonuclear neutrophils (PMN) are the largest leukocyte population in the blood of most mammals including horses, and play an important defensive role in many infectious diseases. However, the mechanisms that increase PMN as one of the main cellular subsets in the defense against pathogens could also be involved in the pathophysiology of dysregulated inflammatory conditions. Mesenchymal stem/stromal cells (MSCs) are a heterogeneous population with a modulatory potential on the inflammatory response and are known to interact with nearly all cells of the immune system, including PMN. In th...
Da Silva AS, Garcia Perez HA, Costa MM, França RT, De Gasperi D, Zanette RA, Amado JA, Lopes ST, Teixeira MM, Monteiro SG.In this study, we reported the first outbreak of the infection by Trypanosoma vivax in horses in southern Brazil, a non-endemic region where bovines have only recently been found infected by this trypanosome species. We evaluated 12 horses from a farm in southern Brazil, where four horses displayed pale mucous membranes, fever, weight loss, and swelling of abdomen, prepuce, or vulva. The diagnosis of T. vivax was confirmed in four horses by morphological parameters of trypomastigotes in blood smears and species-specific PCR. All T. vivax-infected animals showed anemia, and most showed increase...
Ellinger I.Active placental transport of maternal serum calcium (Ca(2+)) to the offspring is pivotal for proper development of the fetal skeleton as well as various organ systems. Moreover, extracellular Ca(2+) levels impact on distinct processes in mammalian reproduction. The calcium-sensing receptor (CaSR) translates changes in extracellular Ca(2+)-concentrations into cellular reactions. This review summarizes current knowledge on the expression of CaSR and its putative functions in reproductive organs. CaSR was detected in placental cells mediating materno-fetal Ca(2+)-transport such as the murine int...
Hu K, Stewart AJ, Yuen KY, Hinrichsen S, Dryburgh EL, Bertin FR.Determination of plasma adrenocotrophic hormone (ACTH) concentration (endogenous or thyrotropin-releasing hormone [TRH] stimulation test) is the most commonly used diagnostic test for pituitary pars intermedia dysfunction (PPID) in horses. Because ACTH is unstable, samples often are frozen to be shipped to laboratories or to allow for batch analysis of research samples. However, the effect of multiple freeze-thaw cycles on equine ACTH is unknown. Objective: To determine the effects of multiple freeze-thaw cycles on immunoreactive ACTH concentration. Methods: Twenty-eight horses ranging from 10...
Hansen S, Otten ND, Birch K, Skovgaard K, Hopster-Iversen C, Fjeldborg J.The pathophysiology of equine asthma (EA) is still not fully described, but the involvement of an allergic reaction is strongly suspected. This theory has led to the use of allergen-specific immunoglobulin (Ig)E tests to support a diagnosis of asthma. The objective of this descriptive study was to evaluate the correlation between four subgroups of EA (mastocytic mild equine asthma [MEA], neutrophilic MEA, mixed MEA, and severe equine asthma [SEA]), allergen specific IgE (measured in both serum and BALF) and mRNA expression of selected genes in bronchoalveolar lavage fluid (BALF). Serum and BAL...
Katavolos P, Ackerley CA, Clark ME, Bienzle D.Horses suffer from recurrent airway obstruction, an asthma-like condition induced by repeat inhalation of environmental substances present in barn air. Clara cell secretory protein (CCSP) is much reduced during active inflammation when neutrophils predominate in the airways, and in chronic asthmatics. We sought to investigate morphologic and functional interactions of CCSP with neutrophils. Bronchoalveolar and blood neutrophils from healthy control animals, and from animals with recurrent airway obstruction in remission and exacerbation, were evaluated by immuno-cytochemistry and immuno-electr...
Hosaka Y, Kirisawa R, Yamamoto E, Ueda H, Iwai H, Takehana K.Although inflammatory activation of cytokines have been analyzed in various tissues, there have only been a few and as-yet-inconclusive studies on cytokines in equine tendons. In this study, the localizations of 4 cytokines (IL-1alpha, IL-1beta, TNFalpha and IFNgamma) in tendinocytes of the equine superficial digital flexor tendon (SDFT) were analyzed by the use of an immunohistochemical method. In inflamed tendons positive staining for all 4 cytokines antibodies were detected in endotedinieum cells and vascular epithelial cells. In contrast, negative or trace immunoreactions were obtained in ...
McFarlane D, Beech J, Cribb A.Thyrotropin releasing hormone (TRH) stimulates an increase in plasma cortisol in horses with pars intermedia dysfunction (PPID, Cushing's disease). A similar phenomenon is observed in humans with Cushing's disease or Nelson's syndrome. The mechanism of the response in humans is not known, but an alteration in receptor expression, selectivity or responsiveness in abnormal corticotropes has been proposed. Horses with PPID, unlike humans, almost exclusively have adenomas of pars intermedia (PI) rather than pars distalis (PD) origin. Therefore, the mechanism responsible for the TRH response observ...
Abraham G, Kottke C, Dhein S, Ungemach FR.Although in the respiratory system there is great therapeutic interest in manipulating and understanding the beta-adrenoceptor-G-protein-adenylate cyclase (AC) signal transduction pathway, little is known on segmental differences among lung, bronchus, and trachea with regard to the receptor concentration and interaction to G-proteins and coupling to AC. In this study, patterns of distribution and absolute quantities of beta-adrenoceptor subtypes beta(1) and beta(2) were determined in membranes of equine lung parenchyma, bronchial and tracheal epithelium with the underlying smooth muscle by sat...
Van Loon G, Duytschaever M, Tavernier R, Fonteyne W, Jordaens L, Deprez P.We describe the development and the different features of an experimental model of chronic atrial fibrillation (AF) in equines. In four healthy ponies a dual-chamber pacemaker, with an adapted pacemaker program, was implanted transvenously in the standing animal. This adapted pacemaker induced episodes of AF by delivering a 2s burst of electrical stimuli (42 Hz) as soon as sinus rhythm was detected. Simultaneous with a surface electrocardiogram, the intra-atrial electrogram could be recorded to determine the atrial electrogram morphology. Programmed electrical stimulation (PES) was used to det...
Caloni F, Cortinovis C.Aflatoxins are a group of mycotoxins principally produced by Aspergillus flavus and A. parasiticus, which are both natural contaminants of food and feedstuff. Aflatoxin B(1) is the most prevalent member of this group that is normally detected and is the most powerful hepatocarcinogen known. Few naturally occurring episodes of aflatoxicosis in horses have been reported in the literature. Indeed, the published information about aflatoxin exposure, metabolism and the effects on horses is limited and controversial, possibly indicating a lack of awareness rather than the rarity of the occurrence. T...
Black SJ, Lunn DP, Yin C, Hwang M, Lenz SD, Belknap JK.The mechanisms that initiate the pathophysiologic changes in the digital laminae in equine laminitis are poorly understood. Due to the fact that (1) the horse at risk of laminitis has many similarities clinically to the human sepsis patient and (2) our recent finding of marked laminar proinflammatory cytokine expression at the developmental time point of the black walnut extract (BWE) model of laminitis, we tested the possibility that, similar to organ damage in human sepsis, leukocyte emigration is an early event in laminitis. Using immunoperoxidase methods with an anti-equine CD13 monoclonal...
