Plasma is the liquid component of blood in horses, consisting primarily of water, electrolytes, proteins, and waste products. It serves as a transport medium for nutrients, hormones, and waste products throughout the body. Plasma also plays a role in maintaining blood pressure and volume, as well as serving as a reservoir for critical proteins involved in clotting and immune responses. Research on equine plasma often focuses on its composition, functions, and applications in veterinary medicine, such as transfusions and diagnostic testing. This page compiles peer-reviewed research studies and scholarly articles that explore the properties, functions, and clinical applications of plasma in equine health.
BERGERET B, BLASCHKO H.The oxidative deamination of cystamine and homocystamine by mammalian oxidases has been studied. The histaminase of pig kidney oxidizes homocystamine much more slowly than cystamine. The amine oxidase of mammalian liver (guinea-pig, rabbit) oxidizes homocystamine more rapidly than cystamine. Both amines are oxidized by plasma (or serum) of ruminants (ox, sheep, goat) and of the horse. In the enzymatic oxidation of homocystamine both aminogroups are removed; there is no evidence that a ring compound analogous to cystaldimine is accumulating.
Gibson RB, Banzhaf EJ.Gravimetric determinations were recorded for the total and several individual proteins (in the sodium oxalate plasma) fractioned with ammonium sulphate and sodium chloride. At precipitation, the plasma salt mixture had been diluted to a final volume of ten times the amount of plasma employed. Coagulations were on aliquot portions of filtrates, and the individual protein constituents (except serumalbumin) were calculated by difference. The eleven horses had been subjected to simultaneous immunization against diphtheria and tetanus toxins, each horse being subsequently continued on the toxin to ...
Minamijima Y, Kuroda T, Okano A, Wakuno A, Yuasa R, Ishikawa Y, Nomura M, Kinoshita K, Yamada M.We examined the pharmacokinetics of intravenous pridinol in six thoroughbred horses. Each horse received a single 20 mg dose of pridinol mesylate via the jugular vein, and plasma and urine samples were collected over 72 h. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify pridinol concentrations in plasma and urine, allowing for the calculation of pharmacokinetic parameters. A three-compartment model best fit the plasma elimination data. Using the Toutain model, irrelevant plasma and urine concentrations were estimated to be 0.00284 and 0.000612 ng/mL, respec...
Hobbs KJ, Ludwig EK, Martin EM, Bayless R, Bauck AG, Freeman DE, Gonzalez LM.To determine if blood and peritoneal fluid levels of syndecan-1, heparan sulfate, and hyaluronan are elevated in horses with small intestinal disease compared to healthy counterparts. Unassigned: 61 horses were categorized into control (n = 20), inflammatory (11), and strangulating (30) groups. Paired peritoneal fluid and blood samples were obtained from each group from December 2016 through December 2024 and analyzed via equine-validated ELISAs for syndecan-1, heparan sulfate, and hyaluronan concentrations. Patient survival to discharge was recorded for all groups. Immunofluorescence staining...
Kranenburg LC, Reinke KS, van den Broek J, Zaal EA, van den Boom R, van Doorn DA.Hydrolysed collagen is used as a supplement for horses with osteoarthritis, hoof horn growth problems, and gastric ulcers. To determine the oral availability of a specific hydrolysed collagen supplement and the appropriate dose, six Warmblood mares were fed two different concentrations of the supplement: 100 g HC (C), 50 g HC (C), and a control of 0 g HC (C) during one week in a randomised cross-over design. On day 7, 14 and 21, blood sampling for amino acid (AA) analysis was performed, just prior to feeding the supplement (t = 0) and every hour after feeding for 8 h (t = 1-8). Statistical ana...
Sala-Ayala L, Cuervo-Arango J, Martínez Boví R.Endometrial edema is an ultrasonographic sign of estrus in mares and is positively associated with fertility. This study aimed to evaluate the influence of follicular size, systemic progesterone (P4), and exogenous estradiol benzoate (EB) on the onset and duration of endometrial edema. In Experiment 1, anestrus (n = 4) and diestrus mares (n = 4) received 4 mg of EB intramuscularly; edema scores and plasma P4 were monitored over four days. In a complementary group (n = 5), mares were monitored until ovulation, then administered 4 mg of EB and examined every 12 h for 48 h. In Experimen...
Sullivan J, Blea J, Morales CJ, McKemie DS, Kass PH, Knych HK.Corticosteroids, such as isoflupredone, are effective anti-inflammatory medications and as such are commonly used to treat inflammation associated with training and injuries in performance horses. While the pharmacokinetics and pharmacodynamics of isoflupredone acetate (IPA) following intra-articular administration to horses has been well described, studies characterizing intramuscular (IM) administration are lacking. The objective of the current study was to describe the pharmacokinetics and anti-inflammatory effects of IPA following IM administration to horses. Twelve horses received a singl...
Fouché N, Howard J, Gerber V, Billmann P, Farinha do Sul M, Christen G, Bruckmaier R, Philipona C, Schmutz NB, Gross J.β-endorphin, a proopiomelanocortin (POMC)-derived peptide secreted by pars intermedia melanotropes, may play a significant but underexplored role in pituitary pars intermedia dysfunction (PPID) pathophysiology and diagnosis. This study aimed to (1) validate a commercially available human β-endorphin enzyme-linked immunosorbent assay (ELISA) kit for equine samples, and (2) compare β-endorphin concentrations between horses with PPID and healthy controls. Assay validation included the generation of standard curves using purified synthetic equine β-endorphin and human β-endorphin standards, w...
James C, Sheahan J, Arthur P.Thoroughbred race performance is influenced by genetics, training, recovery, and management, but decisions about race readiness are often subjective and lack validated physiological markers. This study evaluated thiol-oxidised albumin, a blood-based indicator of oxidative stress, as a potential biomarker of pre-race fitness in Australian Thoroughbreds. Seventy-five clinically healthy racehorses from seven stables were monitored across 216 competitive events (150 races, 66 trials). Blood samples were collected from the jugular at baseline, 48 h pre-race, and for each day up to 8 days post-race ...
Milczek-Haduch D, Żmigrodzka M, Kiełbik P, Świderska B, Olędzki J, Witkowska-Piłaszewicz O.Extracellular vesicles (EVs) are promising biomarkers and mediators of intercellular communication, but their isolation from equine biofluids remains challenging. This study compared two isolation workflows-size-exclusion chromatography (SEC) and differential ultracentrifugation followed by SEC (UC + SEC)-to evaluate their efficiency, reproducibility, and the proteomic composition of EVs derived from equine serum and plasma. Blood from six healthy horses was processed to obtain platelet-free plasma and serum. EVs were isolated using SEC or UC + SEC and characterized by transmission ele...
Jula CA, Davis JL, McKenzie HC, Council-Troche M.To describe the pharmacokinetics of a single dose of pimobendan (Vetmedin) in healthy adult horses and provide preliminary evidence of the absorption of 2 compounded pimobendan formulations. Unassigned: From August 2022 through November 2022, 6 healthy adult horses were administered a single dose of 0.5 mg/kg pimobendan orally. A subset of 2 horses was also administered pimobendan, compounded as an oil-based suspension and a capsule formulation. Plasma was collected at times 0, 15, 30, and 45 minutes and 1, 2, 4, 8, 12, and 24 hours after administration. The plasma concentrations of pimobendan...
Mojsym W, Kowalik S, Chałabis-Mazurek A, Janczarek I, Kędzierski W.Some correlations between serum Cu, Zn and Se and cytokines have been reported in humans. Especially, the Cu:Zn ratio corresponded with inflammation. To date, relationships between microelements and proinflammatory proteins are poorly understood in horses. The aim of the study was to evaluate whether Cu, Zn and Se may influence turnover of IL-6, IL-8 and tissue factor (TF) in breeding and working horses. Blood samples obtained from 66 horses were analysed. There were 37 pregnant broodmares of different breeds, 13 barren broodmares and 16 race Thoroughbred horses. Serum Cu, Zn and Se concentrat...
Wallace PD, Schoonover MJ, Williams MR, Maxwell LK, Taylor JD.To evaluate plasma and synovial fluid amikacin concentrations following cephalic or saphenous IV regional limb perfusion (IVRLP) with a dosing protocol of 25 mg of amikacin/kg, divided into 16.7 mg/kg systemically and 8.3 mg/kg regionally. We hypothesized that plasma amikacin concentrations observed at 30 minutes after systemic administration would exceed a therapeutic target of 53 μg/mL and that synovial fluid concentrations would exceed a therapeutic target of 80 μg/mL. Unassigned: Over a 5-month period (spring/summer of 2023), 8 healthy neonatal foals were administered each protocol at le...
Birckhead EM, Raidal SL, Das S, Raidal SR.Sepsis is a main cause of death in neonatal foals. While the syndrome is not completely understood, sepsis is a dysregulated inflammatory response of the host to infection. It can be difficult to diagnose because of varying and non-specific clinical signs and imperfect diagnostic tests. Increased circulating nucleosome levels have been detected in humans and animals with sepsis, but this has not been documented in foals. Nucleosomes are released extracellularly during neutrophil extracellular trap formation, as well as from damaged and dead cells. We analysed plasma samples from clinically hea...
Klingberg J, Richards S, Hochwallner T, Kennan L, Keledjian J.Bisphosphonate drugs and myo-inositol trispyrophosphate are of concern to the racing industry and have been listed as prohibited substances in equine sports. The current bisphosphonate plasma screening analysis employed at the Australian Racing Forensic Laboratory involves the use of sequential solid-phase extraction procedures, passing the samples through a mixed mode cartridge, followed by a weak anion exchange cartridge. The eluates collected following the second extraction are then methylated and analysed by liquid chromatography-mass spectrometry. Under these extraction conditions, some b...
Richards S, Palmer D, Cawley A, Wainscott M, Keledjian J.An improved screening workflow and a robust capillary flow LC-MS confirmatory method for the detection of recombinant human erythropoietin (rHuEPO) has been implemented to increase the sensitivity of rHuEPO detection and to reduce the number of suspect samples committed to confirmatory testing. The influence of repeated dosing of epoetin-β on the detection window of rHuEPO in equine plasma was assessed using the optimised method. Samples were initially assessed using an economical R&D Human EPO Duo-Set ELISA Development System. Samples indicating a result greater than the batch baseline were ...
