RESUMEN
Exercise confers protection against obesity, type 2 diabetes and other cardiometabolic diseases1-5. However, the molecular and cellular mechanisms that mediate the metabolic benefits of physical activity remain unclear6. Here we show that exercise stimulates the production of N-lactoyl-phenylalanine (Lac-Phe), a blood-borne signalling metabolite that suppresses feeding and obesity. The biosynthesis of Lac-Phe from lactate and phenylalanine occurs in CNDP2+ cells, including macrophages, monocytes and other immune and epithelial cells localized to diverse organs. In diet-induced obese mice, pharmacological-mediated increases in Lac-Phe reduces food intake without affecting movement or energy expenditure. Chronic administration of Lac-Phe decreases adiposity and body weight and improves glucose homeostasis. Conversely, genetic ablation of Lac-Phe biosynthesis in mice increases food intake and obesity following exercise training. Last, large activity-inducible increases in circulating Lac-Phe are also observed in humans and racehorses, establishing this metabolite as a molecular effector associated with physical activity across multiple activity modalities and mammalian species. These data define a conserved exercise-inducible metabolite that controls food intake and influences systemic energy balance.
Asunto(s)
Ingestión de Alimentos , Conducta Alimentaria , Obesidad , Fenilalanina , Condicionamiento Físico Animal , Adiposidad/efectos de los fármacos , Animales , Peso Corporal/efectos de los fármacos , Diabetes Mellitus Tipo 2 , Modelos Animales de Enfermedad , Ingestión de Alimentos/fisiología , Metabolismo Energético , Conducta Alimentaria/fisiología , Glucosa/metabolismo , Ácido Láctico/metabolismo , Ratones , Obesidad/metabolismo , Obesidad/prevención & control , Fenilalanina/administración & dosificación , Fenilalanina/análogos & derivados , Fenilalanina/metabolismo , Fenilalanina/farmacología , Condicionamiento Físico Animal/fisiologíaRESUMEN
There are two FDA-approved bisphosphonate products, clodronate (Osphos®) and tiludronate (Tildren®), for use in horses. It is hypothesized that bisphosphonates can produce analgesic effects and prevent proper healing of microcracks in bone. Therefore, bisphosphonate use is banned in racehorses. However, bisphosphonates have a short detection window in the blood before sequestration in the skeleton, making the reliability of current drug tests questionable. Seven exercising Thoroughbred horses were administered clodronate (1.8 mg/kg i.m.), and four were administered saline. RNA was isolated from peripheral blood mononuclear cells (PBMCs) collected immediately before a single dose of clodronate or saline and then on Days 1, 6, 28, 56 and 182 post-dose. mRNA was sequenced and analysed for differentially expressed transcripts. While no single transcripts were differentially expressed, pathway analysis revealed that p38 MAPK (p = .04) and Ras (p = .04) pathways were upregulated, and cadherin signalling (p = .02) was downregulated on Day 1. Previously investigated biomarkers, cathepsin K (CTSK) and type 5 acid phosphatase (ACP5), were analysed with RT-qPCR in a targeted gene approach, with no significant difference observed. A significant effect of time on gene expression for ACP5 (p = .03) and CTSK (p < .0001) was observed. Thus, these genes warrant further investigation for detecting clodronate use over time.
Asunto(s)
Conservadores de la Densidad Ósea , Ácido Clodrónico , Regulación de la Expresión Génica , Animales , Caballos/sangre , Ácido Clodrónico/farmacología , Conservadores de la Densidad Ósea/farmacología , Conservadores de la Densidad Ósea/administración & dosificación , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Femenino , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/metabolismoRESUMEN
BACKGROUND: Lidocaine is a local anesthetic that is sometimes administered in combination with epinephrine. The addition of epinephrine increases the time lidocaine remains at the site of administration, thus prolonging the duration of effect. Due to their potential to prevent the visual detection of lameness, the administration of local anesthetics is strictly regulated in performance and racehorses. Recent reports of positive regulatory findings for lidocaine in racehorses suggests a better understanding of the behavior of this drug is warranted. The objective of the current study was to describe serum and urine concentrations and the pharmacokinetics of lidocaine and its primary metabolites following administration in combination with epinephrine, as a palmar digital nerve block in horses. Twelve horses received a single administration of 1 mL of 2% lidocaine HCl (20 mg/horse) with epinephrine 1:100,000, over the palmar digital nerve. Blood samples were collected up to 30 h and urine samples up to 48 h post administration. Lidocaine and metabolite concentrations were determined by liquid chromatography- mass spectrometry and pharmacokinetic (non-compartmental and compartmental) analysis was performed. RESULTS: Serum concentrations of lidocaine and 3-hydroxylidocaine were above the LOQ of the assay at 30 h post administration and monoethylglycinexylidide (MEGX) and glycinexylidide (GX) were below detectable levels by 24 and 48 h, respectively. In urine, lidocaine, MEGX and GX were all non-detectable by 48 h post administration while 3-hydroxylidocaine was above LOQ at 48 h post administration. The time of maximal concentration for lidocaine was 0.26 h (median) and the terminal half-life was 3.78 h (mean). The rate of absorption (Ka) was 1.92 1/h and the rate of elimination (Kel) was 2.21 1/h. CONCLUSIONS: Compared to previous reports, the terminal half-life and subsequent detection time observed following administration of lidocaine in combination with epinephrine is prolonged. This is likely due to a decrease in systemic uptake of lidocaine because of epinephrine induced vasoconstriction. Results of the current study suggest it is prudent to use an extended withdrawal time when administering local anesthetics in combination with epinephrine to performance horses.
Asunto(s)
Anestésicos Locales , Bloqueo Nervioso , Caballos , Animales , Anestésicos Locales/farmacología , Lidocaína , Epinefrina , Bloqueo Nervioso/veterinariaRESUMEN
The in vivo metabolism and pharmacokinetics of flunixin meglumine and phenylbutazone have been extensively characterized; however, there are no published reports describing the in vitro metabolism, specifically the enzymes responsible for the biotransformation of these compounds in horses. Due to their widespread use and, therefore, increased potential for drug-drug interactions and widespread differences in drug disposition, this study aims to build on the limited current knowledge regarding P450-mediated metabolism in horses. Drugs were incubated with equine liver microsomes and a panel of recombinant equine P450s. Incubation of phenylbutazone in microsomes generated oxyphenbutazone and gamma-hydroxy phenylbutazone. Microsomal incubations with flunixin meglumine generated 5-OH flunixin, with a kinetic profile suggestive of substrate inhibition. In recombinant P450 assays, equine CYP3A97 was the only enzyme capable of generating oxyphenbutazone while several members of the equine CYP3A family and CYP1A1 were capable of catalyzing the biotransformation of flunixin to 5-OH flunixin. Flunixin meglumine metabolism by CYP1A1 and CYP3A93 showed a profile characteristic of biphasic kinetics, suggesting two substrate binding sites. The current study identifies specific enzymes responsible for the metabolism of two NSAIDs in horses and provides the basis for future study of drug-drug interactions and identification of reasons for varying pharmacokinetics between horses.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacocinética , Clonixina/análogos & derivados , Sistema Enzimático del Citocromo P-450/metabolismo , Caballos/metabolismo , Fenilbutazona/farmacocinética , Animales , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/metabolismo , Clonixina/química , Clonixina/metabolismo , Clonixina/farmacocinética , ADN Complementario/genética , ADN Complementario/metabolismo , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Estructura Molecular , Fenilbutazona/química , Fenilbutazona/metabolismoRESUMEN
Flunixin meglumine is a highly efficacious nonsteroidal anti-inflammatory drug commonly used in equine medicine and especially in performance horses. Recently, a new transdermal flunixin meglumine product has been approved for use in cattle. Although not currently approved for use in the horse, the convenience of this product may prove appealing for use in horses, warranting study. Six horses were administered a single transdermal dose of 500 mg and blood and urine samples collected for up to 96 h post-administration. Serum for determination of thromboxane concentrations and whole blood samples was collected at various time and challenged with lipopolysaccharide, calcium ionophore, or methanol to induce ex vivo synthesis of eicosanoids. Concentrations of flunixin, 5-OH flunixin, and eicosanoids were measured using LC-MS/MS and non-compartmental pharmacokinetic analysis performed on concentration data. Serum concentrations of flunixin and 5-OH flunixin were above the limit of quantitation at 96 h post-administration in both serum and urine. The mean (range) for Cmax , Tmax and the terminal half-life were 515.6 (369.7-714.0) ng/ml, 8.67 (8.0 12.0) h, and 22.4 (18.3-42.5) h, respectively. Following transdermal administration, based on effects on eicosanoid synthesis, flunixin meglumine inhibited cyclooxygenase 1 and 2 and 15-lipooxygenase activity, with anti-inflammatory effects lasting for 24-72 h.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacocinética , Clonixina/farmacocinética , Enfermedades de los Caballos , Administración Cutánea , Animales , Biomarcadores , Bovinos , Cromatografía Liquida/veterinaria , Clonixina/análogos & derivados , Enfermedades de los Caballos/tratamiento farmacológico , Caballos , Inflamación/veterinaria , Espectrometría de Masas en Tándem/veterinariaRESUMEN
Methylphenidate is a powerful central nervous system stimulant with a high potential for abuse in horse racing. The detection of methylphenidate use is of interest to horse racing authorities for both prior to and during competition. The use of hair as an alternative sampling matrix for equine anti-doping has increased as the number of detectable compounds has expanded. Our laboratory developed a liquid chromatography-high-resolution mass spectrometry method to detect the presence of methylphenidate in submitted samples. Briefly, hair was decontaminated, cut, and pulverized prior to liquid-liquid extraction in basic conditions before introduction to the LC-MS system. Instrumental analysis was conducted using a Thermo Q Exactive mass spectrometer using parallel reaction monitoring using a stepped collision energy to obtain sufficient product ions for qualitative identification. The method was validated and limits of quantitation, linearity, matrix effects, recovery, accuracy, and precision were determined. The method has been applied to confirm the presence of methylphenidate in official samples submitted by racing authorities.
Asunto(s)
Cabello/química , Extracción Líquido-Líquido/métodos , Metilfenidato/análisis , Animales , Cromatografía Liquida , Caballos , Espectrometría de Masas , Detección de Abuso de Sustancias/veterinariaRESUMEN
Although controversial, due to its reported effectiveness in attenuating bleeding associated with exercise-induced pulmonary hemorrhage (EIPH), furosemide is currently a permitted race day medication in most North American racing jurisdictions. The objective of this study was to assess the efficacy of furosemide in reducing the presence and severity of EIPH when administered 24 hr prior to strenuous treadmill exercise. Eight exercised Thoroughbred horses received saline or 250 mg of furosemide either 4 or 24 hr prior to high-speed treadmill exercise in a balanced 3-way cross-over design. Blood samples were collected for determination of furosemide, lactate, hemoglobin, blood gas, and electrolyte concentrations. Heart rate and pulmonary arterial pressure were measured throughout the run and endoscopic examination and bronchoalveolar lavage (BAL) performed. Horses were assigned an EIPH score and the number of red blood cells in BAL fluid determined. Although not significantly different, endoscopic EIPH scores were lower in the 4-hr versus the 24-hr and saline groups. RBC counts were not significantly different between the treatment groups. Pulmonary arterial pressures were significantly increased at higher speeds; however, there were no significant differences between dose groups when controlling for speed. A small sample size and unknown bleeding history warrant a larger-scale study.
Asunto(s)
Diuréticos/farmacología , Furosemida/farmacología , Condicionamiento Físico Animal , Privación de Agua , Animales , Presión Sanguínea/efectos de los fármacos , Estudios Cruzados , Diuréticos/administración & dosificación , Esquema de Medicación , Femenino , Furosemida/administración & dosificación , Caballos , Ácido Láctico/sangre , MasculinoRESUMEN
BACKGROUND: Clodronate is a potent antiresorptive agent labelled for use in horses over 4 years of age, for the treatment of navicular syndrome. Concerns regarding the extra-label use of clodronate in equine athletes, such as racehorses, have been raised as inhibition of osteoclast activity by clodronate has been postulated to interfere with normal bone healing, which is imperative to the repair of microfractures. The paucity of data describing the long-term pharmacokinetics of clodronate and effects on biomarkers of bone resorption necessitates further study. OBJECTIVES: (1) To determine clodronate concentrations in blood and urine over a 6-month period in horses undergoing treadmill exercise and (2) to assess the effects of clodronate on protein biomarkers of bone remodelling in this same group of horses. STUDY DESIGN: Randomised controlled experimental study. METHODS: Seven exercised Thoroughbred horses received a single im administration of 1.8 mg/kg clodronate and four horses received an equivalent volume of saline. Blood and urine samples were collected prior to, during and for 182 days post drug administration for drug concentration determination using liquid chromatography-tandem mass spectrometry, and determination of protein biomarker (CTX-1 and TRAcP5B) concentrations. RESULTS: Clodronate was detectable in blood for 14-175 days and for up to 175 days in urine. For some horses, concentrations were nondetectable at one time point but detectable at a subsequent time point. The terminal serum half-life ranged from 1.80 to 283.9 days. CTX-1 concentrations were significantly higher, relative to baseline, in both treated and control groups while concentrations of TRAcP5B were significantly lower in the treated group. MAIN LIMITATIONS: Relatively small number of horses studied. CONCLUSIONS: Based on assessment of protein biomarkers, clodronate appears to influence osteoclasts at label doses. Furthermore, results of this study support racing regulations that preclude horses administered bisphosphonates for medical reasons, from racing for a prolonged period of time.
CONTEXTO: Clodronato é um agente antirreabsortivo potente e recomendado para o uso em cavalos com mais de 4 anos de idade, para o tratamento da síndrome do navicular. Há preocupação com o uso indiscriminado de clodronato em equinos atletas, como cavalos de corrida, já que a inibição da atividade dos osteoclastos pelo clodronato tem sido postulada em interferir na cicatrização óssea normal, o que é essencial para a cicatrização de microfraturas. A escassez de informação quanto às ações prolongadas do uso de clodronato e seus efeitos nos biomarcadores de reabsorção óssea requere mais estudos. OBJETIVOS: (1) Determinar a concentração de clodronato no sangue e urina por um período de 6 meses em cavalos submetidos ao exercício em esteira e (2) acessar os efeitos de clodronato nos biomarcadores de remodelação óssea no mesmo grupo de cavalos. DELINEAMENTO DO ESTUDO: Estudo controlado randomizado. METODOLOGIA: Sete cavalos Puro-Sangue Inglês em exercício receberam uma única dose im de 1.8 mg/kg de clodronato e 4 cavalos receberam um volume equivalente de solução fisiológica. Amostras de sangue e urina foram coletadas antes, durante e por 182 dias após a administração de clodronato. Valores de concentração da droga foram determinados utilizando cromatografia líquida-espectrometria de massa (LC-MS/MS), e determinação da concentração de biomarcadores (CTX-1 e TRAcP5B) também foi realizada. RESULTADOS: Clodronato foi detectado no sangue por 14-175 dias e por até 175 dias na urina. Para alguns equinos, a concentração foi não-detectável em um momento, mas detectável no próximo momento. O valor terminal da vida-média em soro foi 1.80-283.9 dias. A concentração de CTX-1 foi significativamente elevada, relativo às amostras iniciais, em ambos os grupos (tratamento e controle), enquanto as concentrações de TRAcP5B foram significativamente menores no grupo de cavalos tratados. PRINCIPAIS LIMITAÇÕES: Número relativamente pequenos de cavalos no estudo. CONCLUSÕES: Baseado nos resultados dos biomarcadores, clodronato parece influencia osteoclastos na dose recomendada. Além disso, os resultados deste estudo suportam o regulamento de cavalos de corrida que impedem que cavalos que receberam bifosfonatos por razão médica de competir por um período de tempo prolongado.
Asunto(s)
Líquidos Corporales , Resorción Ósea , Enfermedades de los Caballos , Caballos , Animales , Ácido Clodrónico/farmacología , Ácido Clodrónico/uso terapéutico , Resorción Ósea/tratamiento farmacológico , Resorción Ósea/veterinaria , Difosfonatos/uso terapéutico , Biomarcadores , Enfermedades de los Caballos/tratamiento farmacológicoRESUMEN
Epiploic foramen entrapment (EFE) is a common cause of small intestinal colic in horses and may lead to intestinal strangulation. Strangulating intestinal obstruction impairs the gastrointestinal outflow and can lead to secondary gastric rupture and endotoxemia. Clostridioides difficile can cause enterotyphlocolitis with colic in horses of all ages, and the process is commonly referred to as C. difficile-associated disease (CDAD). Here we report the results of the postmortem examination of a 7-y-old Thoroughbred racehorse with concurrent CDAD, EFE, and gastric rupture that was euthanized following a history of colic over several days. A segment of distal jejunum and proximal ileum had passed through the epiploic foramen, and the intestinal wall was thickened and dark-red. The remaining small intestinal loops were distended and filled with blood-tinged contents. Peritonitis had resulted from escape of gastric contents into the abdominal cavity through a tear in the major curvature of the stomach. Histologically, the incarcerated segment had acute transmural hemorrhage with congestion and mucosal necrosis; neutrophilic infiltrates with fibrin thrombi were in the mucosa of the non-incarcerated small intestinal segments. C. difficile toxins were detected in the small intestinal contents, and C. difficile was isolated from the small intestine, colon, and cecum.
Asunto(s)
Clostridioides difficile , Cólico , Enfermedades de los Caballos , Rotura Gástrica , Animales , Clostridioides , Clostridium , Cólico/complicaciones , Cólico/veterinaria , Enfermedades de los Caballos/diagnóstico , Caballos , Rotura Gástrica/complicaciones , Rotura Gástrica/veterinariaRESUMEN
Zilpaterol is a ß2 -adrenergic agonist and a repartitioning agent that has a high potential for abuse in equine performance athletes. Analysis of zilpaterol in hair is an alternative sampling matrix that extends detection time periods beyond those found in urine or blood samples. Our laboratory has been screening for zilpaterol in hair for many years and recently detected and confirmed its presence in official samples. Accordingly, a liquid chromatography-mass spectrometry method was developed and validated to detect and confirm zilpaterol in equine hair. Briefly, equine hair was decontaminated, cut, and pulverized prior to disruption and liquid-liquid extraction in basic conditions. Following extraction, the sample was introduced to an Agilent 1260 HPLC and zilpaterol was separated using a reverse phase gradient with a total run time of 12.5 min. Following chromatographic separation, zilpaterol and its corresponding stable isotope labeled internal standard were introduced via positive mode electrospray ionization to a Thermo Q-Exactive Plus mass spectrometer and spectra collected using parallel reaction monitoring. The methodology was validated using in-house criteria including characterization of accuracy, precision, recovery, linear range, matrix effects, limit of detection, and limit of quantitation, and the method was found to be fit-for-purpose to confirm the presence of zilpaterol in equine hair. This methodology has been used to detect and confirm the presence of zilpaterol from out-of-competition hair samples submitted by regional racing authorities.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Detección de Abuso de Sustancias/métodos , Espectrometría de Masas en Tándem/métodos , Compuestos de Trimetilsililo/análisis , Agonistas de Receptores Adrenérgicos beta 2/análisis , Animales , Cromatografía Líquida de Alta Presión/veterinaria , Doping en los Deportes/prevención & control , Cabello/química , Caballos , Límite de Detección , Extracción Líquido-Líquido/métodos , Detección de Abuso de Sustancias/veterinaria , Espectrometría de Masas en Tándem/veterinariaRESUMEN
More and more studies are reporting on the natural transmission of SARS-CoV-2 between humans with COVID-19 and their companion animals (dogs and cats). While horses are apparently susceptible to SARS-CoV-2 infection based on the homology between the human and the equine ACE-2 receptor, no clinical or subclinical infection has yet been reported in the equine species. To investigate the possible clinical role of SARS-CoV-2 in equids, nasal secretions from 667 horses with acute onset of fever and respiratory signs were tested for the presence of SARS-CoV-2 by qPCR. The samples were collected from January to December of 2020 and submitted to a commercial molecular diagnostic laboratory for the detection of common respiratory pathogens (equine influenza virus, equine herpesvirus-1/-4, equine rhinitis A and B virus, Streptococcus equi subspecies equi). An additional 633 serum samples were tested for antibodies to SARS-CoV-2 using an ELISA targeting the receptor-binding domain of the spike protein. The serum samples were collected from a cohort of 587 healthy racing Thoroughbreds in California after track personnel tested qPCR-positive for SARS-CoV-2. While 241/667 (36%) equids with fever and respiratory signs tested qPCR-positive for at least one of the common respiratory pathogens, not a single horse tested qPCR-positive for SARS-CoV-2. Amongst the racing Thoroughbreds, 35/587 (5.9%) horses had detectable antibodies to SARS-CoV-2. Similar to dogs and cats, horses do not seem to develop clinical SARS-CoV-2 infection. However, horses can act as incidental hosts and experience silent infection following spillover from humans with COVID-19. SARS-CoV-2-infected humans should avoid close contact with equids during the time of their illness.
RESUMEN
Bisphosphonates are potent anti-resorptive agents that have the potential to adversely affect bone healing in equine athletes, and normal bone adaption in young racehorses. A concern exists that bisphosphonate inhibition of normal bone metabolism could lead to increased bone fractures during high-intensity exercise. We found only a single report describing concentrations of tiludronate in the bone of horses, and no studies describing clodronate. Knowledge of the residence time in bone could allow for a better understanding of the long-term effects of these compounds. Our objectives were to develop a method for detection of bisphosphonates in bone and add to the limited information available regarding the disposition of these drugs in the bone of horses. Two horses received clodronate and 2 tiludronate disodium. Postmortem collection of bones and teeth occurred either 4 or 30 d post drug administration. Additionally, postmortem blood, synovial fluid, aqueous humor, and bone samples from racehorses with various histories of bisphosphonate administration were collected, and concentrations determined using the developed LC-MS/MS method. Bisphosphonates were detected in bones and teeth tested at 4 and 30 d. In a postmortem sample, clodronate was detected in bone from a horse with reported administration 18 mo prior; clodronate was not detected in other sample types collected from this horse. Bisphosphonates reside in bone for extended periods of time, which could lead to potential long-term effects, increasing the potential for bone fractures in young and/or athletic horses.
Asunto(s)
Difosfonatos , Espectrometría de Masas en Tándem , Animales , Cromatografía Liquida/veterinaria , Caballos , Espectrometría de Masas en Tándem/veterinariaRESUMEN
The most prevalent causes of death in racehorses are musculoskeletal injuries, causing ~83% of deaths within the racing industry in California and elsewhere. The vast majority of these injuries have preexisting lesions that predispose to fatal injury. A 4-y-old Thoroughbred colt suffered an acute suspensory apparatus failure, including biaxial proximal sesamoid bone fractures of the right front fetlock, causing loss of support of the fetlock joint and consequent fall with fractures of the cervical and sacral spine. Cervical fracture caused spinal cord damage that resulted in sudden death. A preexisting lesion in the medial proximal sesamoid bone likely predisposed to complete fracture of this bone and fetlock breakdown. Interestingly, a comparable osteopenic lesion was present in the intact medial proximal sesamoid bone of the left forelimb, which is consistent with bilateral repetitive overuse injury in racehorses. The morphologic features of the cervical and sacral spine fractures were compatible with acute injury; no evidence of preexisting lesions was seen. Most likely, these acute vertebral fractures occurred as a result of the horse falling. This case emphasizes the importance of performing a detailed autopsy in horses that suffer an appendicular musculoskeletal injury, particularly in fatal cases when the horse dies following a leg injury.
Asunto(s)
Muerte Súbita/veterinaria , Caballos/lesiones , Huesos Sesamoideos/lesiones , Traumatismos de la Médula Espinal/veterinaria , Fracturas de la Columna Vertebral/veterinaria , Animales , Muerte Súbita/etiología , Fracturas Óseas/veterinaria , Masculino , Huesos Sesamoideos/patología , Traumatismos de la Médula Espinal/complicaciones , Fracturas de la Columna Vertebral/complicacionesRESUMEN
BACKGROUND: Tibial fractures cause ~3% of racehorse deaths. Pre-existing stress fractures have been associated with multiple racing and training fractures, but not complete tibial fractures. OBJECTIVES: To describe racehorse tibial fractures and compare signalment and exercise histories of affected and control racehorses. STUDY DESIGN: Retrospective analysis of necropsy reports. METHODS: Racehorses that had a complete tibial fracture (1990-2018) were retrospectively reviewed. Signalment and exercise histories of affected horses were compared to 1) racehorses that died because of non-tibial musculoskeletal injuries or 2) non-musculoskeletal cause and 3) age, sex, event-matched control racehorses. Tibial fracture prevalence was described relative to California racehorses that had at least one official work or race. Age, sex and limb distributions were compared between affected and control horses (Chi-square, Fisher's Exact test). Exercise history data were reduced to counts and rates of official high speed works, races and layups (periods without an official high speed work or race >60 days). Variables were compared among groups using matched logistic regression (P ≤ .05). RESULTS: Tibial fractures in 115 horses (97% unilateral; 50% left, 47% right) occurred most commonly during training (68%) and in 2- to 3-year-old horses (73%). Fractures were predominantly comminuted (93%), diaphyseal (44%) and oblique (40%). Of 61 cases examined for callus, 64% had periosteal callus associated with fracture, most commonly in proximal (65%) and distal diaphyseal (27%) locations. Of 28 racehorses with known exercise history, 57% never raced and 36% had a layup. Affected horses had fewer official-timed works and events (official high speed works and races), number of active days and accumulated less distance in events and works (P < .05) than control horses. MAIN LIMITATIONS: Retrospective review of necropsy reports by multiple pathologists over 28 years. CONCLUSIONS: Tibial fractures were associated with pre-existing stress fracture early in career. Most fractures were associated with proximolateral stress fractures.
Asunto(s)
Fracturas Óseas , Fracturas por Estrés , Enfermedades de los Caballos , Deportes , Fracturas de la Tibia , Animales , Fracturas Óseas/epidemiología , Fracturas Óseas/veterinaria , Fracturas por Estrés/veterinaria , Caballos , Modelos Logísticos , Estudios Retrospectivos , Fracturas de la Tibia/epidemiología , Fracturas de la Tibia/veterinariaRESUMEN
Recombinant human erythropoietin (rHuEPO) is a well-known performance enhancing drug in human athletes, and there is anecdotal evidence of it being used in horse racing for the same purpose. rHuEPO, like endogenous EPO, increases arterial oxygen content and thus aerobic power. Micro-doping, or injecting smaller doses over a longer period of time, has become an important concern in both human and equine athletics since it is more difficult to detect. Horses offer an additional challenge of a contractile spleen, thus large changes in the red blood cell mass occur naturally. To address the challenge of detecting rHuEPO doping in horse racing, we determined the transcriptomic effects of rHuEPO micro-dosing over seven weeks in exercised Thoroughbreds. RNA-sequencing of peripheral blood mononuclear cells isolated at several time points throughout the study identified three transcripts (C13H16orf54, PUM2 and CHTOP) that were significantly (PFDR < 0.05) different between the treatment groups across two or three time point comparisons. PUM2 and CHTOP play a role in erythropoiesis while not much is known about C13H16orf54, but it is primarily expressed in whole blood. However, gene expression differences were not large enough to detect via RT-qPCR, thereby precluding their utility as biomarkers of micro-doping.
Asunto(s)
Biomarcadores/metabolismo , Eritropoyetina/genética , Caballos/genética , Proteínas Recombinantes/genética , Transcriptoma/genética , Animales , Doping en los Deportes/métodos , Eritropoyesis/genética , Humanos , Leucocitos Mononucleares/metabolismo , Deportes/fisiología , Factores de Transcripción/genéticaRESUMEN
BACKGROUND: Flunixin meglumine (FM) and phenylbutazone (PBZ) are potent anti-inflammatory agents and as such their potential to mask injuries that would otherwise keep a horse from training or racing is concerning. A common practice in racetrack medicine in the USA is to administer the two drugs within close proximity (24 hours apart) of each other, raising the concern of pharmacokinetic interactions and enhanced anti-inflammatory effects. OBJECTIVES: Describe the pharmacokinetics and effects of PBZ on the clearance of FM when administered in close proximity as well as effects on inflammatory mediators. STUDY DESIGN: Two-way randomised balanced crossover experiment. METHODS: Twelve Thoroughbred exercised horses received 500 mg FM IV alone or in combination with 2 g of IV PBZ 24 hours later. Blood and urine samples were collected prior to and for up to 120 hours post-drug administration. Whole blood samples were collected at various times and challenged with lipopolysaccharide or calcium ionophore to induce ex vivo synthesis of eicosanoids. Concentrations of FM, PBZ and eicosanoids were measured using LC-MS/MS and noncompartmental pharmacokinetic analysis performed on concentration data. RESULTS: Flunixin meglumine clearance was significantly increased when horses received PBZ 24 hours post-administration (P = .03). No other differences in pharmacokinetic parameters were noted between groups. Thromboxane B2 was significantly suppressed, relative to baseline for 96 hours post-FM administration. Subsequent administration of PBZ prolonged the suppression. Prostaglandin E2 was decreased for 24 hours following administration of FM with subsequent administration of PBZ prolonging the suppression until 120 hours. PGF2alpha concentrations were decreased for up to 168 hours post-FM administration. FM administration significantly decreased 15-HETE. MAIN LIMITATIONS: Small sample size and lack of a phenylbutazone-only treatment group. CONCLUSIONS: Administration of PBZ post-FM administration increased FM clearance. The anti-inflammatory effects of FM appear to be prolonged when PBZ is administered 24 hours post-administration.
Asunto(s)
Antiinflamatorios no Esteroideos , Clonixina , Caballos/metabolismo , Fenilbutazona/farmacocinética , Animales , Antiinflamatorios no Esteroideos/farmacocinética , Cromatografía Liquida/veterinaria , Clonixina/análogos & derivados , Clonixina/farmacocinética , Espectrometría de Masas en Tándem/veterinariaRESUMEN
Corticosteroids are potent anti-inflammatory drugs and as such are commonly administered to performance and racehorses. The objectives of the current study were to describe blood and urine concentrations and the pharmacokinetics and effects on cortisol and inflammatory mediator concentrations, following intravenous and oral administration to 12 exercised horses. Horses received an intravenous administration of 40 mg of dexamethasone sodium phosphate and 20 mg of dexamethasone tablets with a 4 week washout in between administrations. Blood and urine samples were collected prior to and for up to 96 hours post drug administration. Whole blood samples were collected at various time points and challenged with lipopolysaccharide or calcium ionophore to induce ex vivo synthesis of eicosanoids. The concentrations of dexamethasone and eicosanoids were measured using LC-MS/MS and the concentrations from both routes of administration fit simultaneously using a three-compartment pharmacokinetic model. A turnover model with inhibition of Kin gave an adequate fit to the dexamethasone-cortisol PKPD data. Serum and urine dexamethasone concentrations were at the limit of quantitation at 96 and 48 hours post administration, respectively. The volume of distribution, systemic clearance, and terminal half-life was 0.907 L/kg, 7.89 mL/h/kg, and 1.34 h, respectively. The IC50 for cortisol suppression was 0.007 ng/mL. Stimulation of dexamethasone treated blood with lipopolysaccharide and calcium ionophore resulted in an inhibition of inflammatory biomarker production for a prolonged period of time post drug administration. The results of this study suggest that dexamethasone has a prolonged anti-inflammatory effect following intravenous or oral administration to horses.
Asunto(s)
Antiinflamatorios/administración & dosificación , Dexametasona/análogos & derivados , Glucocorticoides/administración & dosificación , Modelos Biológicos , Administración Intravenosa , Administración Oral , Animales , Antiinflamatorios/farmacocinética , Antiinflamatorios/farmacología , Cromatografía Liquida/métodos , Dexametasona/administración & dosificación , Dexametasona/farmacocinética , Dexametasona/farmacología , Glucocorticoides/farmacocinética , Glucocorticoides/farmacología , Semivida , Caballos , Inflamación/tratamiento farmacológico , Mediadores de Inflamación/metabolismo , Concentración 50 Inhibidora , Espectrometría de Masas en Tándem/métodos , Factores de Tiempo , Distribución TisularRESUMEN
The objective of this study was to determine viral loads, strain (neuropathogenic versus non-neuropathogenic) and state (lytic, non-replicating, latent) of equine herpesvirus-1 (EHV-1) by real-time polymerase chain reaction (PCR) in the blood and nasopharyngeal secretions of adult horses following natural exposure. The index case, a 4-year-old Thoroughbred gelding with confirmed EHV-1 myeloencephalopathy, as well as potentially exposed horses, were sampled over a period of 3 weeks. The study population comprised of 39 adult Thoroughbred horses and 35 adult "pony" and outrider horses of various breeds housed at a racetrack in Northern California. Blood samples and nasopharyngeal secretions (NPS) from all horses were tested on several occasions for EHV-1 DNA viral loads, targeting the glycoprotein B (gB) gene, viral strain, targeting the ORF 30 gene, and transcriptional activity of EHV-1, targeting the gB gene and latency-associated transcripts (LATs). Viral loads and transcriptional activity of the gB gene declined rapidly in the index case following antiviral treatment. The prevalence of EHV-1 infection in NPS determined by PCR slowly decreased over the 22 day study period from 25% to 14%. The initial surveillance showed multiple clusters of exposure, one associated with the index case and two related to horses that had recently returned from a different racetrack. Viral strain differentiation showed that only two horses (the index case and a neighboring horse) were infected with only a neuropathogenic strain, while all other horses were infected with either a non-neuropathogenic strain or were dually infected with both neuropathogenic and non-neuropathogenic strains. In most cases, the virus was present in either a lytic or a non-replicating form, while latent virus was found in blood and NPS much less frequently. The molecular approach used in this study showed promise for assessing the risk of exposing other horses to EHV-1 and for studying viral kinetics in infected horses.
Asunto(s)
Reservorios de Enfermedades/veterinaria , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/aislamiento & purificación , Enfermedades de los Caballos/virología , Animales , California , ADN Viral/química , ADN Viral/genética , Brotes de Enfermedades/veterinaria , Reservorios de Enfermedades/virología , Femenino , Infecciones por Herpesviridae/epidemiología , Infecciones por Herpesviridae/transmisión , Infecciones por Herpesviridae/virología , Enfermedades de los Caballos/epidemiología , Enfermedades de los Caballos/transmisión , Caballos , Masculino , Reacción en Cadena de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa/veterinaria , Prevalencia , Carga Viral/veterinaria , Latencia del VirusRESUMEN
Phenylbutazone (PBZ) is a potent mon-steroidal anti-inflammatory drug used commonly in performance horses. The objectives of the current study were to describe blood and urine concentrations and the pharmacokinetics of PBZ and its metabolites following intravenous (IV) and oral administration and to describe the duration of pharmacodynamic effect. To that end, 17 horses received an IV administration and 18 horses an oral administration of 2 g of PBZ. Blood and urine samples were collected prior to and for up to 96 hours post drug administration. Whole blood samples were collected at various time points and challenged with lipopolysaccharide or calcium ionophore to induce ex vivo synthesis of eicosanoids. Concentrations of PBZ and eicosanoids were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and non-compartmental pharmacokinetic analysis performed on concentration data from IV and oral administration. Serum concentrations of PBZ and its metabolites were below the limit of quantitation at 96 hours post administration. The volume of distribution at steady state, systemic clearance, and terminal half-life was 0.194 ± 0.019 L/kg, 23.9 ± 4.48 mL/h/kg, and 10.9 ± 5.32 hours, respectively. The terminal half-life following oral administration was 13.4 ± 3.01 (paste) and 15.1 ± 3.96 hours (tablets). Stimulation of PBZ treated whole blood with lipopolysaccharide and calcium ionophore resulted in an inhibition of TXB2 , PGE2 , LTB4 and 15-HETE production for a prolonged period of time post drug administration. The results of this study suggest that PBZ has a prolonged anti-inflammatory following IV or oral administration of 2 g to horses.
Asunto(s)
Antiinflamatorios no Esteroideos/administración & dosificación , Enfermedades de los Caballos/prevención & control , Caballos , Inflamación/veterinaria , Fenilbutazona/administración & dosificación , Administración Intravenosa , Administración Oral , Animales , Antiinflamatorios no Esteroideos/sangre , Antiinflamatorios no Esteroideos/orina , Biomarcadores/sangre , Monitoreo de Drogas , Eicosanoides/sangre , Enfermedades de los Caballos/sangre , Enfermedades de los Caballos/diagnóstico , Caballos/sangre , Caballos/orina , Inflamación/sangre , Inflamación/diagnóstico , Inflamación/prevención & control , Fenilbutazona/sangre , Fenilbutazona/orinaRESUMEN
Methamphetamine is a central and peripheral nervous system stimulant. There is only a single study that describes exposure to and disposition of this compound in horses. The potential for abuse and inadvertent exposure in equine athletes along with the limited data available necessitates further study. The objectives of the current study were to describe drug and metabolite concentrations, develop an analytical method that could be used to regulate its use, and describe selected pharmacodynamic effects. In phase 1, six horses were randomized into three transmucosal dose groups (n = 2/group; 0.5, 1.0 or 10 mg). In phase 2, horses received a single 10 mg intravenous dose. In phase 3, the effects of urinary pH on elimination were studied. Blood and urine samples were collected for up to 72 hours post drug administration. Concentrations of methamphetamine were measured using liquid chromatography-tandem mass spectrometry. Methamphetamine was below the limit of detection (LOD) in blood by 2, 4, and 18 hours following transmucosal administration of 0.5, 1, and 10 mg, respectively. Following intravenous administration, methamphetamine fell below the LOD between 12 and 18 hours. Following urinary acidification, methamphetamine fell below the limit of quantitation (LOQ) by 12 hours. In urine, methamphetamine was no longer detected at 48, 48, and 72 hours in the 0.5, 1, and 10 mg transmucosal groups and 18 hours in the intravenous group. Increased urinary pH resulted in urinary concentrations of methamphetamine falling below detectable levels by 48 hours post transmucosal administration. While the number of animals was small, behavioral, stimulatory, and cardiac effects were minimal.