Platelets are small, anucleated cell fragments derived from megakaryocytes in the bone marrow, playing a key role in hemostasis and thrombosis in horses. They contribute to the formation of blood clots by adhering to the site of vascular injury, aggregating with one another, and facilitating the coagulation process. In equine medicine, platelet count and function are important parameters in assessing bleeding disorders and thrombotic conditions. Variations in platelet count can indicate underlying health issues, such as inflammation, infection, or bone marrow disorders. This page compiles peer-reviewed research studies and scholarly articles that explore the physiology, pathology, and clinical implications of platelets in equine health.
Stokol T, Serpa PBS, Brooks MB, Divers T, Ness S.Equine herpesvirus type 1 (EHV-1) is a major cause of infectious respiratory disease, abortion and neurologic disease. Thrombosis in placental and spinal vessels and subsequent ischemic injury in EHV-1-infected horses manifests clinically as abortion and myeloencephalopathy. We have previously shown that addition of heparin anticoagulants to equine platelet-rich plasma (PRP) can abolish ex vivo EHV-1-induced platelet activation. The goal of this study was to test whether platelets isolated from horses treated with unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) were resista...
Hübers E, Bauer N, Fey K, Moritz A, Roscher K.The retrospective study aimed to evaluate the prevalence of true thrombocytopenia and ethylenediaminetetraacetic acid (EDTA)-induced pseudothrombocytopenia in horses and ponies and to assess the diagnostic and prognostic utility of true thrombocytopenia. Methods: In 3592 patients (2008-2015) hematological data (ADVIA® 2120, Siemens) were reviewed. Inclusion criteria were platelet counts < 90 x 109/l (EDTA-blood) and/or < 84 x 109/l (citrate blood). Thrombocytopenia was classified as true, EDTA-induced, and questionable. Patients with true thrombocytopenia were assigned to nine groups ac...
Lorenzo FDR.Non-unions at forearms are usually challenging and difficult to treat. If additionally, an infection is present, reconstructive surgery should be planned only after full debridement, antibiotic treatment, and confirmation, based on clinical observation and laboratory tests that the infection has subsided. Bone grafting may be required for reconstruction. The use of autogenous bone calls for a second surgical site with an increased risk of morbidity. Using bone substitutes may reduce the need for autogenous bone. Stimulating factors, such as bone marrow concentrate (BMC) and demineralized bone ...
Shawaf T, Hussen J, Al-Zoubi M, Hamaash H, Al-Busadah K.The Shetland ponies, which originate from harshest environments in the world islands in the north of the Atlantic Ocean, are now most popular pony breed distributed in almost every corner of the world. Reference ranges of physiological, biochemical and haematological values, which are widely used in veterinary clinics, may differ according to season, age, sex, type of feeding, and environmental circumstances of the area. Reference ranges of haematological and biochemical values of Shetland ponies are rare. The present study was therefore undertaken to evaluate the impact of season, age and sex...
Naskou MC, Sumner SM, Chocallo A, Kemelmakher H, Thoresen M, Copland I, Galipeau J, Peroni JF.Mesenchymal stem cells (MSCs) produced for clinical purposes rely on culture media containing fetal bovine serum (FBS) which is xenogeneic and has the potential to significantly alter the MSC phenotype, rendering these cells immunogenic. As a result of bovine-derived exogenous proteins expressed on the cell surface, MSCs may be recognized by the host immune system as non-self and be rejected. Platelet lysate (PL) may obviate some of these concerns and shows promising results in human medicine as a possible alternative to FBS. Our goal was to evaluate the use of equine platelet lysate (ePL) poo...
D'Ascola A, Bruschetta G, Zanghì G, Campo S, Medica P, Campana S, Ferlazzo G, Gibbs BF, Ferlazzo AM.Serotonin (5-HT) is a neurohormone transported from plasma into platelets and leukocytes by a specific transporter (SERT). While it is known that the brain 5-HT system is modulated by physical exercise, the peripheral serotoninergic response to exercise is not yet fully elucidated. In particular, this study aimed to evaluate changes in plasma 5-HT levels and equine leukocyte SERT expression in response to treadmill exercise in untrained horses. Analyses were carried out pre- and post-treadmill exercise. 5-HT plasma levels were analysed by HPLC. Leukocytes and platelets were isolated to perform...
Jamieson CA, Hanzlicek AS, Payton ME, Holbrook TC.To determine reference intervals and the effect of sample agitation and rest time on Sonoclot analysis in healthy adult horses. Methods: Original prospective study. Methods: University veterinary medical teaching hospital. Methods: Sixty healthy adult horses. Methods: Blood was collected for assessment of complete blood count, serum biochemical analysis, and Sonoclot analysis. Results: Horses were determined to be healthy based upon physical examination, CBC, and serum biochemistry analysis. Blood was analyzed in a glass bead-containing cuvette using the Sienco Sonoclot analyzer following 2 re...
Seabaugh KA, Thoresen M, Giguère S.Extracorporeal shockwave therapy (ESWT) and platelet-rich plasma (PRP) are common treatments for soft tissue injuries in horses. Shockwave triggers cell specific responses to promote healing. Growth factors released from PRP also promote healing. It has been hypothesized that greater growth factor release would amplify the healing process. The combination of ESWT and PRP could promote healing in injured tendons and ligaments in the horse. The objective of this study was to determine if application of shockwaves to PRP samples increases the concentration of transforming growth factor-β1 (TGF-...
Naskou MC, Norton NA, Copland IB, Galipeau J, Peroni JF.Platelet lysate (PL) has been extensively used for the laboratory expansion of human mesenchymal stem cells (MSC) in order to avoid fetal bovine serum (FBS) which has been associated with immune-mediated host reactions and transmission of bovine-origin microbial contaminants. Before suggesting the routine use of PL for MSC culture, we wanted to further investigate whether PL alone might trigger inflammatory responses when exposed to reactive white blood cells such as monocytes. Our objectives were to evaluate the inflammatory profile of equine monocytes cultured with equine PL (ePL) and to det...
Rushton JO, Kammergruber E, Tichy A, Egerbacher M, Nell B, Gabner S.Despite advances in therapy of corneal ulcerative diseases in horses, a vast number of cases require surgical intervention, due to poor response to treatment. Topical application of serum has been used for many years, based on its anticollagenolytic properties and the presence of growth factors promoting corneal wound healing. However, although other blood derived products i.e. platelet rich plasma (PRP), plasma rich in growth factors (PRGF) have been widely used in equine orthopaedics and in human ophthalmology, no reports of the effects of these blood derived products exist in equine ophthal...
Pereira RCDF, De La Côrte FD, Brass KE, da Silva Azevedo M, Gallio M, Cantarelli C, Dau SL, Cezar AS, Inkelmann MA.Wounds localized on the distal limbs in horses are difficulty healing. No studies have been conducted to evaluate homologous platelet-rich plasma (PRP) in horses. The aim of this study was to evaluate the effect upon applying autologous PRP, homologous PRP, and autologous PRP gel on the wound healing process of wounds on the distal limb of horses. To study a possible correlation between the platelet count and wound healing time, four skin wounds of 4 cm2 were surgically created on the dorsolateral aspect of the third metacarpus in eight healthy adult horses. Each skin wound was randomly treate...
Angelone M, Conti V, Biacca C, Battaglia B, Pecorari L, Piana F, Gnudi G, Leonardi F, Ramoni R, Basini G, Dotti S, Renzi S, Ferrari M, Grolli S.Laminitis, a highly debilitating disease of the foot in ungulates, is characterized by pathological changes of the complex lamellar structures that maintain the appendicular skeleton within the hoof. Laminitis is a multifactorial disease that involves perturbation of the vascular, hematological, and inflammatory homeostasis of the foot. Interestingly, the pathogenesis of the disease resembles what is observed in metabolic syndromes and sepsis-induced organ failure in humans and animals. We hypothesized that local administration of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) mi...
Beerts C, Suls M, Broeckx SY, Seys B, Vandenberghe A, Declercq J, Duchateau L, Vidal MA, Spaas JH.Poor healing of tendon and ligament lesions often results in early retirement of sport horses. Therefore, regenerative therapies are being explored as potentially promising treatment for these injuries. In this study, an intralesional injection was performed with allogeneic tenogenically induced mesenchymal stem cells and platelet-rich plasma 5-6 days after diagnosis of suspensory ligament (SL) (n = 68) or superficial digital flexor tendon (SDFT) (n = 36) lesion. Clinical, lameness and ultrasonographic evaluation was performed at 6 and 12 weeks. Moreover, a survey was performed 12 ...
Segabinazzi LG, Friso AM, Correal SB, Crespilho AM, Dell'Aqua JA, Miró J, Papa FO, Alvarenga MA.Persistent mating-induced endometritis (PMIE) results in decreased fertility in horses, thereby causing a significant impact in the horse market. Platelet-rich plasma (PRP), a modulator of the inflammatory response, has been largely used in veterinary medicine. Here, we investigated the effects of PRP on uterine inflammation, conception rate, endometrial polymorphonuclear neutrophil (PMN) migration, and COX-2 protein levels in the endometrial tissue. Thirteen PMIE-susceptible mares were used for artificial insemination (AI). The mares were inseminated with fresh semen in three consecutive cycl...
Ness SL, Frye AH, Divers TJ, Rishniw M, Erb HN, Brooks MB.OBJECTIVE To determine effects of oral administration of Yunnan Baiyao on platelet activation, coagulation, and fibrinolysis in healthy horses. ANIMALS 12 healthy adult horses. PROCEDURES In a randomized blinded crossover study that included a 4-week washout period between treatments, horses were orally administered a paste containing Yunnan Baiyao (15 mg/kg) or placebo at 12-hour intervals for 3 days. Blood samples were collected before start of treatment (time 0) and at 24 and 72 hours for a CBC, measurement of fibrinogen concentration, coagulation screening tests, and a panel of assays to a...
Carmona JU, Ríos DL, López C, Álvarez ME, Pérez JE.Platelet-rich plasma (PRP) preparations are used in horses with osteoarthritis (OA). However, some controversies remain regarding the ideal concentration of platelets and leukocytes to produce an adequate anti-inflammatory and anabolic response in the synovial membrane. The aims of this study were to study the influence of leukoconcentrated platelet-rich gel (Lc-PRG) and leukoreduced platelet-rich gel (Lr-PRG) supernatants on the quantitative expression of some proinflammatory and anabolic genes in equine synovial membrane explants (SMEs) challenged with lipopolysaccharide (LPS). SMEs from six...
Fukuda K, Miyata H, Kuwano A, Kuroda T, Tamura N, Kotoyori Y, Kasashima Y.Platelet-rich plasma (PRP) therapy is promising for treating skeletal muscle injuries in human athletes by promoting muscle regeneration. It might also be useful for treating muscle injuries in equine athletes. In the present study, muscle regeneration induced by injection of PRP into intact muscle of Thoroughbred was investigated. Autologous PRP and saline were injected twice into intact left and right gluteus medius muscles of seven clinically healthy Thoroughbreds. Muscle samples were collected from the injection sites by needle biopsy at 2 and 7 days after PRP injection. Immunohistochemica...
Jiménez-Aristizabal RF, López C, Álvarez ME, Giraldo C, Prades M, Carmona JU.To compare the temporal release (over three weeks) of tumor necrosis factor alpha (TNF-α), interleukin 4 (IL-4), IL-1 receptor antagonist (IL-1ra), platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta-1 (TGF-β1) from two platelet-rich fibrin (PRF) preparations from equine blood obtained at either 240g/8min or 416g/10min. Whole blood from 10 horses was used to obtain PRF clots by two different centrifugation protocols. After 1h of rest, PRF clots were deposited in wells with culture medium, which was changed at 6h, 24h and then every 48h to 21days. Cytokines and GFs...
Davitkov D, Davitkov D, Vucicevic M, Stanisic L, Radakovic M, Glavinic U, Stanimirovic Z.Equine piroplasmosis in donkeys has been recognised as a serious problem of major economic importance. The present molecular study is the first investigation of the presence of Theileria equi and Babesia caballi in Balkan donkeys and of the possible haematological alterations related to it. A total of 70 apparently healthy donkeys from Serbia were included in this study. The overall prevalence of T. equi infection in donkeys tested with multiplex PCR was 50%. There was no B. caballi-positive sample. Infections in donkeys included in this study seem to be associated with decreased red blood cel...
Giannetto C, Arfuso F, Fazio F, Giudice E, Pietro SD, Bruschetta D, Piccione G.Depending on the intensity, duration and type of physical exercise, equine metabolism has to adapt to nervous, cardiovascular, endocrine and respiratory system requirements. In horses, exercise and training are known to have considerable effects on the mechanisms of hemostatic system involving platelet activity. The aim of the present study was to evaluate the effect of different training schedules on platelet aggregation in 15 Italian Saddle jumping horses. Animals were divided into three equal groups: Group A was subjected to a high intensity-training program; group B to a light training pro...
Sumner SM, Naskou MC, Thoresen M, Copland I, Peroni JF.Platelet preparations containing growth factors, attachment factors, and enzymes are appealing to enhance healing of injured tissues and as an alternative to xenogenic serum in cell culture media. Plateletpheresis is commonly used to collect platelets in human medicine but has not been validated in horses. Plateletpheresis to collect platelet concentrate was performed on six female, mixed breed, chemically restrained horses using commercially available apheresis equipment. Before and immediately after plateletpheresis, we performed physical examinations and collected blood for chemistry and co...
Bozorgmanesh R, Sutton-Burges JW, Tablin F.Equine whole blood collection and storage methods have been evaluated to assess red blood cell viability; however, platelet (PLT) viability has not been comprehensively assessed. Objective: The purpose of the study was to compare viability of PLTs collected in whole blood into 2 different anticoagulants. Methods: Whole blood from 6 healthy adult Thoroughbred horses was collected into citrate-phosphate-dextrose-adenine (CPDA) or acid-citrate-dextrose (ACD). Platelet count, pH, and concentrations of glucose, lactate, carbon dioxide, oxygen, bicarbonate, sodium, potassium, and chloride were measu...
Roscher KA, Failing K, Schenk I, Moritz A.The reasons for this prospective experimental study were to determine a dosing scheme with loading and maintenance dose of aspirin inducing inhibition of platelet function measured by whole blood impedance aggregometry. Ten horses received aspirin orally in the morning with one loading dose of 4.7-5 mg/kg and maintenance doses of 1-1.3 mg/kg daily the following 4 days. Aggregometries (COLtest, ASPItest, ADPtest) and serum salicylic acid were measured. ASPItest showed significant difference in inhibition at 24 and 48 hr (p < .05) and 96 hr (p < .01). Significant change for ADPtes...
Andriichuk A, Tkachenko H.The objective of this study was to assess the influence of exercise of average intensity in the haematological and biochemical values, as well as acidic resistance of erythrocytes in mares and stallions of Holsteiner breed. A total of seventeen horses of Holstein breed (seven mares and 10 stallions aged 6 years) were used in this study. The blood samples were assessed for haematocrit (HCT) value, haemoglobin concentration (HGB), the amount of red blood cells (RBC), white blood cells (WBC), platelets (PLT), leucogram, mean corpuscular haemoglobin concentration (MCHC), mean corpuscular volume (...
Hernandez D, Yeo WM, Brooks MB, Ness SL, Divers TJ, Stokol T.OBJECTIVE To evaluate the effects of treatment of horses with standard platelet inhibitors on ex vivo inhibition of platelet activation by equine herpesvirus type I (EHV-I). ANIMALS II healthy adult horses. PROCEDURES In a double-blinded, placebo-controlled crossover study, horses were treated orally for 5 days with theophylline (5 mg/kg, q 12 h), pentoxifylline (10 mg/kg, q 12 h), clopidogrel bisulfate (4 mg/kg, q 24 h), acetylsalicylic acid (20 mg/kg, q 24 h), or placebo. Horses received all treatments, each separated by a 3-week washout period. Platelet-rich plasma was prepared from citrate...
Stokol T, Serpa PBS, Zahid MN, Brooks MB.Equid herpes virus type-1 (EHV-1) is a major pathogen of horses, causing abortion storms and outbreaks of herpes virus myeloencephalopathy. These clinical syndromes are partly attributed to ischemic injury from thrombosis in placental and spinal vessels. The mechanism of thrombosis in affected horses is unknown. We have previously shown that EHV-1 activates platelets through virus-associated tissue factor-initiated thrombin generation. Activated platelets participate in thrombus formation by providing a surface to localize coagulation factor complexes that amplify and propagate thrombin genera...
Giraldo CE, Álvarez ME, Carmona JU.To compare five activation methods in equine platelet-rich plasma (PRP) by determination of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta 1 (TGF-β1) concentrations in platelet-rich gel (PRG) supernatants. Methods: Platelet-rich plasma from 20 horses was activated by calcium chloride (CC), calcium gluconate (CG), bovine thrombin (BT), and their combinations, BTCC and BTCG. Both growth factor concentrations in PRG supernatants were measured by ELISA and compared with plasma and platelet lysates (PL) over time. Results: Growth factor concentrations were signific...
Burkett BN, Thomason JM, Hurdle HM, Wills RW, Fontenot RL.Determine the effects of nonsteroidal anti-inflammatory drugs (NSAID) on platelet function and thromboxane synthesis immediately after drug administration and following 5 days of NSAID administration in healthy horses. Methods: Randomized cross-over study. Methods: Healthy adult horses (n=9; 6 geldings and 3 mares). Methods: Horses received either flunixin meglumine (1.1 mg/kg IV every 12 hours), phenylbutazone (2.2 mg/kg IV every 12 hours), or firocoxib (loading dose of 0.27 mg/kg IV on day 1, then 0.09 mg/kg IV every 24 hours for 4 days) for a total of 5 days. Blood samples were collected pr...
Rodríguez-Pozo ML, Armengou L, Monreal L, Viu J, Cesarini C, Jose-Cunilleras E.To assess whether an oral direct factor Xa inhibitor (DiXaI) anticoagulant drug used at the low end of the recommended dose in people achieves presumed prophylactic plasma concentrations and does not induce bleeding in horses. Methods: Experimental study. Methods: Field study. Methods: Ten healthy adult horses. Methods: A DiXaI was administered at a dose of 0.125 mg/kg every 24 h orally for 4 days. Following a wash-out period of 2 weeks, 8 of 10 horses received daily subcutaneous doses of a low molecular weight heparin (dalteparin) for 4 consecutive days at 50 IU/kg. In both trials, antifactor...
Andriichuk A, Tkachenko H.The objective of this study was to assess the influence of exercise of average intensity in the haematological and biochemical values, as well as acidic resistance of erythrocytes in mares and stallions of Holsteiner breed. A total of seventeen horses of Holstein breed (seven mares and 10 stallions aged 6 years) were used in this study. The blood samples were assessed for haematocrit (HCT) value, haemoglobin concentration (HGB), the amount of red blood cells (RBC), white blood cells (WBC), platelets (PLT), leucogram, mean corpuscular haemoglobin concentration (MCHC), mean corpuscular volume (...
Macieira S, Rivard GE, Champagne J, Lavoie JP, Bédard C.An 18-month-old Oldenbourg filly was presented with a bleeding diathesis. Laboratory testing included platelet count, gingival bleeding time, prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor (vWf) antigen, clottable fibrinogen, clot retraction time, PFA-100 closure time, platelet aggregometry (on platelet-rich plasma), and thrombelastography (TEG). TEG was performed by using kaolin and tissue factor as coagulation activators. Expression of the platelet receptor for fibrinogen was assessed by flow cytometry by using anti CD41 (alpha(IIb) or glycoprotein...
Satué K, Hernández Á, Lorente C, Fazio E, Medica P.The purpose of this study was to test the hypothesis that age and sex significantly modulate the changes in hematological parameters of physiologically healthy Spanish Purebred horse, establishing the reference values. Blood samples were obtained on a total of 159 horses (n = 77 males and n = 82 females), classified in four age groups: group A (1-2 years; n = 39), group B (>2-3 years; n = 38), group C (>3-4 years; n = 41), and group D (>4-7 years; n = 41). By means ADVIA 2020i, red blood cell (RBC), hemoglobin concentration (HB), packed cell volume, mean corpuscular volume (MCV), mea...
Johnstone IB, Viel L, Crane S, Whiting T.The purpose of this study was to determine whether a defect in hemostasis might be a factor in the etiology of exercise-induced pulmonary hemorrhage (EIPH). Hemostatic parameters were evaluated in 22 EIPH-positive and ten EIPH-negative racing horses while in a rested state. Nineteen EIPH-positive and ten EIPH-negative horses were further evaluated just before and immediately after a 15 min exercise period on a 260 m oval track. When EIPH-positive and EIPH-negative horses were compared at rest, there was no significant difference in any of the coagulation and fibrinolytic parameters studied. Th...
Piccione G, Grasso F, Fazio F, Giudice E.The goal of this study was to investigate the influence of physical activity on the daily rhythm of platelet aggregation and body temperature in horses. Blood samples from 12 Thoroughbred horses, six sedentary animals and six athletes (studied both before and after a period of inactivity) were collected at 4h intervals for 48h via an intravenous cannula inserted into the jugular vein. Body temperature was recorded every 4h for 48h with a rectal probe. Platelet aggregation was measured with an aggregometer. Collagen was used to test the aggregation of the plasma samples. Statistical analysis of...
Bauer N, Nakagawa J, Dunker C, Failing K, Moritz A.The automated laser-based hematology analyzer Sysmex XT-2000iV™ providing a complete blood cell count (CBC) and 5-part differential has been introduced in large veterinary laboratories. The aim of the current study was to determine precision, linearity, and accuracy of the Sysmex analyzer. Reference method for the accuracy study was the laser-based hematology analyzer ADVIA® 2120. For evaluation of accuracy, consecutive fresh blood samples from healthy and diseased cats (n = 216), dogs (n = 314), and horses (n = 174) were included. A low intra-assay coefficient of variation (CV) of approxim...
Haupt JL, Donnelly BP, Nixon AJ.To evaluate the effects of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) on the metabolic function and morphologic features of equine superficial digital flexor tendon (SDFT) in explant culture. Animals-6 euthanized horses (2 to 5 years old). Methods: Forelimb SDFT explants were cultured for 6 days as untreated control specimens or treated with rhPDGF-BB (1, 10, 50, or 100 ng/mL of medium). Treatment effects on explant gene expression were evaluated via real-time PCR analysis of collagen type I, collagen type III, PDGF-A, and PDGF-B mRNA. Explants were assayed for total colla...
Scalco R, de Oliveira GN, da Rosa Curcio B, Wooten M, Magdesian KG, Hidai ST, Pandit P, Aleman M.Rapid and accurate markers to aid diagnosis of sepsis are needed in neonatal foals. The CBC variable red blood cell distribution width (RDW) to platelet ratio (RPR) is associated with inflammatory response and linked to poor outcomes of sepsis in human patients. Objective: Explore the correlation of RPR with sepsis in neonatal foals and evaluate RPR predictive and prognostic value. Methods: Three hundred seventeen hospitalized neonatal foals ≤7 days of age that had a CBC and physical exam performed at admission between 2012 and 2021. Methods: Retrospective case-control study. Clinical reco...
Michelotto PV, Muehlmann LA, Zanatta AL, Bieberbach EWR, Kryczyk M, Fernandes LC, Nishiyama A.This study investigated the putative roles of inflammation and platelet-activating factor (PAF) in exercise-induced pulmonary haemorrhage (EIPH). Two-year-old Thoroughbred colts (n=37) were exercised on a racetrack for 5months before commencement of the study. Each colt was then exercised at 15-16m/s over 800-1000m and broncho-alveolar lavage fluid (BALF) was collected 24h later. The colts were subsequently divided into two groups on the basis of BALF analysis; an EIPH-positive group (presence of haemosiderophages, n=23) and an EIPH-negative group (absence of haemosiderophages, n=14). BALF fro...
Johnstone IB, Crane S.The incidence and nature of coagulation abnormalities in horses presented with colic and the possible prognostic value of these abnormalities was investigated. A coagulogram was performed on each of 24 adult Thoroughbred or Standardbred horses. A coagulogram consisted of measurements of eight parameters; platelet count, plasma fibrinogen, plasma antithrombin III (AT), partial thromboplastin time (PTT), prothrombin time (PT), thrombin clotting time (TCT), soluble fibrin monomer (SFM) and fibrin-fibrinogen degradation products (FDP). Retrospective determination of the cause of the colic and outc...
Menzies-Gow NJ, Bailey SR, Katz LM, Marr CM, Elliott J.Lipopolysaccharide (LPS) infusion reduces digital perfusion, but the mediators responsible remain undetermined. Objective: To identify vasoconstrictor mediators released following LPS infusion and relate their appearance in plasma to digital blood flow alterations. Methods: Blood flow in the lateral digital vessels of 6 Thoroughbred horses, following a 30 min infusion of LPS (E. coli 055:B5; 30 ng/kg), was measured using Doppler ultrasonography. Concomitant measurements of hoof wall and coronary band surface temperatures (HWST and CBST) were made. Serial blood samples were collected and plasma...
O'Shea CM, Werre SR, Dahlgren LA.(1) To compare the performance of 4 platelet counting technologies in equine platelet concentrates and (2) to evaluate the ability of the Magellan platelet rich plasma (PRP) system to concentrate equine platelets. Methods: Experimental study to assess method agreement. Methods: Adult mixed breed horses (n = 32). Methods: Acid citrate dextrose-A anti-coagulated whole blood was collected and PRP produced using the Magellan system according to the manufacturer's instructions. Platelets were quantified using 4 counting methods: optical scatter (Advia 2120), impedance (CellDyn 3700), hand counting,...
Fairbairn SM, Page CP, Lees P, Cunningham FM.Previous studies have shown that bronchoalveolar lavage fluid from horses with allergic respiratory disease and showing clinical symptoms contains increased numbers of neutrophils. In some cases, the eosinophil count is also increased. In this study the time course of changes in lung function and the accumulation of radiolabelled leucocytes and platelets in the lungs of allergic and normal horses has been examined during a 7 hr allergen exposure. Antigen challenge had no effect on pleural pressure or the distribution of radiolabelled neutrophils, eosinophils or platelets in normal horses. In c...
Braune S, Walter M, Schulze F, Lendlein A, Jung F.For in vitro studies assessing the interaction of platelets with implant materials, common and standardized protocols for the preparation of platelet rich plasma (PRP) are lacking, which may lead to non-matching results due to the diversity of applied protocols. Particularly, the aging of platelets during prolonged preparation and storage times is discussed to lead to an underestimation of the material thrombogenicity. Here, we study the influence of whole blood- and PRP-storage times on changes in platelet morphology and function. Blood from apparently healthy subjects was collected according...
Norris JW, Pratt SM, Auh JH, Wilson SJ, Clutter D, Magdesian KG, Ferraro GL, Tablin F.Bleeding in racing horses associated with exercise appears to be multifactorial, and clinical investigation into severe cases rarely occurs. Previously, we reported a severe bleeding diathesis in a Thoroughbred mare. Herein, we describe the cellular physiology of this defect, provide a diagnostic tool for identifying it, and demonstrate that the dysfunction is heritable. Objective: The subject has a heritable defect in platelet secretion that reduces thrombin generation in the absence of additional plasma factors and delays the onset of thrombin production even in the presence of these factors...
Burkett BN, Thomason JM, Hurdle HM, Wills RW, Fontenot RL.Determine the effects of nonsteroidal anti-inflammatory drugs (NSAID) on platelet function and thromboxane synthesis immediately after drug administration and following 5 days of NSAID administration in healthy horses. Methods: Randomized cross-over study. Methods: Healthy adult horses (n=9; 6 geldings and 3 mares). Methods: Horses received either flunixin meglumine (1.1 mg/kg IV every 12 hours), phenylbutazone (2.2 mg/kg IV every 12 hours), or firocoxib (loading dose of 0.27 mg/kg IV on day 1, then 0.09 mg/kg IV every 24 hours for 4 days) for a total of 5 days. Blood samples were collected pr...
Ríos DL, López C, Carmona JU.The aims were as follows: (1) to evaluate the effects at 48 and 96 h of two concentrations (25 and 50%) of leukocyte and platelet-rich gel (L-PRG) and pure PRG (P-PRG) supernatants on the production/degradation in normal equine synovial membrane explants (SME) of platelet derived growth factor isoform BB, transforming growth factor beta-1, tumor necrosis factor alpha, interleukin (IL-) 4 (IL-4), IL-1 receptor antagonist (IL-1ra), and hyaluronan (HA) synthesis and (2) to correlate these molecules with their respective PRG supernatant treatments. SME from 6 horses were cultured for 96 h with...
Epstein KL, Brainard BM, Lopes MA, Barton MH, Moore JN.To develop a standardized technique for thrombelastography (TEG) analysis in healthy adult horses, with and without the ex vivo addition of tissue factor (TF) as an activator. To determine reference intervals for TEG parameters in the horse, and to determine if traditional coagulation tests correlate with TEG. Methods: Prospective, observational. Methods: Veterinary teaching hospital. Methods: Twenty-six healthy adult horses. Methods: None. Results: Thrombelastography with (TF-TEG) and without (TEG) the addition of TF performed by 4 operators. Coagulation profiles (prothrombin time, activated ...
Jiménez-Aristazábal RF, Carmona JU, Prades M.The aims of the present study were (1) to describe the microscopic and ultrastructural appearance of equine platelet-rich fibrin (PRF) clots and (2) to determine the release and degradation of transforming growth factor beta 1 (TGF-β) and insulin-like growth factor type I (IGF-I) from PRF clots incubated over 14 days. Whole blood from six horses was collected into plain tubes and centrifuged at 240 g for 8 minutes. Clots were evaluated by histology and by both transmission and scanning electronic microscopy (TEM and SEM). Growth factor concentrations were measured by ELISA at 48-hour inter...
Ranjithkumar M, Kamili NM, Saxena A, Dan A, Dey S, Raut SS.Oxidant/antioxidant equilibrium disturbance has already been reported in trypanosome infections by several authors. The present study was aimed to explore the possible oxidant/antioxidant disturbance in surra of naturally infected horses before and after treatment. Fifteen naturally infected horses were chosen to analyse erythrocytic indices, platelet counts, lipid peroxides (LPO), nitric oxide (NO), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) while six healthy animals acted as control. There was a highly significant (P<0.001) reduction in red blood cell (RBC) c...
Brooks MB, Divers TJ, Watts AE, Ness SL, Frye AH, Stokol T, Fubini SL.To evaluate the platelet activation response before and after treatment with clopidogrel in horses. Methods: 12 healthy adult mares. Methods: In a masked study, horses (6/group) were randomly allocated to alternately receive placebo or clopidogrel via nasogastric tube at a loading dose of 4 mg/kg followed by 2 mg/kg every 24 hours. Blood samples were collected before and 72 hours after initiation of treatment for ADP- and collagen-induced light transmission aggregometry; determination of closure time in collagen-ADP cartridges; modified thrombelastography for comparison of maximal amplitudes g...
Wright ME, Croser EL, Raidal S, Baral RM, Robinson W, Lievaart J, Freeman KP.Clinical pathology results are typically interpreted by referring to population-based reference intervals. The use of individualised (subject-based) reference intervals is more appropriate for measurands with a high degree of variation between individuals. Objective: To determine the biological variation of routinely analysed equine haematology and biochemistry measurands and calculate indices of individuality and reference change values which enable production of individualised reference intervals, in a group of healthy, privately owned horses. Methods: In a prospective cohort study, thirty-n...
McMichael M, Smith SA, McConachie EL, Lascola K, Wilkins PA.In several species, there is a strong correlation between indicators of red cell mass (RCM) and thromboelastometry results. The horse has a reliable, temporary, polycythemia in response to phenylephrine infusion. Our objective was to evaluate the effects of an in-vivo increase in circulating RCM on thromboelastometry results in an equine model of transient polycythemia. Six healthy research horses had whole blood thromboelastometry with contact activator and tissue factor initiation after recalcification of citrated samples. Additional samples were frozen for thrombin-antithrombin (TAT). Compl...
Camargo Garbin L, McIlwraith CW, Frisbie DD.Platelet-rich plasma (PRP) as well as other platelet-derived products have been used as a potential disease-modifying treatment for musculoskeletal diseases, such as osteoarthritis (OA). The restorative properties of such products rely mainly on the high concentrations of growth factors, demonstrating encouraging results experimentally and clinically. Yet, the autologous blood-derived nature of the PRP product lead to limitations that precludes it's widespread use. The main limitations for PRP use are; product variability, the need for minimum laboratory settings in most cases, and the need fo...
Lee EB, Kim JW, Seo JP.Platelet rich plasma (PRP) is popularly used in the horse industry to enhance regeneration of tissue injury that has limitation of blood supply. This study aimed to compare the methods for platelet rich plasma preparation since they has not been established yet. Blood was collected from six horses and platelets were concentrated by three different methods (2-step centrifugation, separated centrifugation and separated centrifugation using histopaque). Concentrated blood was analyzed using Advia hematology systems. In the result, separated centrifugation with histopaque showed the significantly ...
Segura D, Monreal L, Pérez-Pujol S, Pino M, Ordinas A, Brugués R, White JG, Escolar G.We studied equine platelet function and activation using ultrastructural examination, flow cytometry, and perfusion. The main aim of the study was to evaluate hemostatic mechanisms in horses using these techniques. Ultrastructural observations were done on resting and activated platelets. Flow cytometry was used to evaluate binding of antibodies to major platelet glycoproteins (GPIIb-IIIa, GPIV, and GPIb) and activation-dependent antigens (P-selectin and lysosomal integral membrane protein [LIMP]). Perfusion techniques were used to evaluate the interaction between platelets and damaged subendo...
Bazzano M, Giannetto C, Fazio F, Rizzo M, Giudice E, Piccione G.The aim of the study was to assess changes in some haematological parameters of periparturient mares from the last three months of pregnancy until the third week after foaling. The study was carried out on 15 healthy pregnant mares (Group A) and 7 healthy non-pregnant non-lactating mares (Group B). Blood samples were collected by jugular venipuncture into EDTA tubes and tested for Haematocrit (Hct), Red Blood Cell (RBC), Haemoglobin (Hb), Platelets (Plt) and White Blood Cell (WBC). Peripheral blood smears were also performed to assess changes in the leucocyte differential count. Group A showed...
Blong AE, Epstein KL, Brainard BM.To investigate the in vitro effects of 3 hydroxyethyl starch (HES) solutions on viscoelastic coagulation testing and platelet function in horses. Methods: Blood samples collected from 7 healthy adult horses. Methods: Blood samples were diluted with various crystalloid and HES solutions to approximate the dilution of blood in vivo that occurs with administration of a 10 and 20 mL/kg fluid bolus to a horse (1:8 and 1:4 dilutions, respectively). Diluted samples were analyzed through optical platelet aggregometry, platelet function analysis, thromboelastography, and dynamic viscoelastic coagulomet...
Giordano A, Rossi G, Pieralisi C, Paltrinieri S.The ADVIA 120 is an automated laser cell counter widely used in veterinary medicine. Although specific software for equine samples is available and validated, only a few reports have been published comparing the ADVIA 120 with other methods for equine hemogram evaluation. Objective: The purpose of this study was to compare the hematologic values and reference intervals obtained on the ADVIA 120 with those obtained on an impedance cell counter and manual differential counts in healthy horses. Methods: EDTA-anticoagulated blood samples were obtained from 114 clinically healthy horses of various ...
