Enzymes are biological catalysts that facilitate biochemical reactions in horses by lowering the activation energy required for these processes. They are involved in various physiological functions, including digestion, metabolism, and cellular repair. Common enzymes in equine biology include amylase, lipase, and lactate dehydrogenase, each playing a specific role in the breakdown of nutrients and energy production. The activity and concentration of these enzymes can vary in response to different physiological and pathological conditions, serving as potential indicators in veterinary diagnostics. This page compiles peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical implications of enzymes in equine health.
Thorpe CT, Stark RJ, Goodship AE, Birch HL.Damage to the flexor tendons, particularly the superficial digital flexor tendon (SDFT), is one of the most common musculoskeletal injuries sustained by horses competing in all disciplines. Our previous work has shown that SDFTs from different individuals show a wide variation in mechanical strengths; this is important clinically as it may relate to predisposition to injury. The high mechanical strength of tendon relies on the correct orientation of collagen molecules within fibrils and stabilisation by the formation of chemical cross-links between collagen molecules. It is not known whether t...
Kawai M, Kuwano A, Hiraga A, Miyata H.The myonuclear domain (MND) is the region of cytoplasm governed by a single myonucleus. Myonuclear domain size is an important factor for muscle fibre plasticity because each myonucleus has limitations in the capacity of protein synthesis. Previous studies have demonstrated that differences in MND size exist in different fibre types in several species, including horses. Objective: To understand the basic mechanism of muscle plasticity, the relationships between MND size, muscle fibre type population and metabolic properties of skeletal muscles throughout the whole body in Thoroughbred horses w...
Franck T, Votion DM, Ceusters J, De La Rebière de Pouyade G, Mouithys-Mickalad A, Niesten A, Fraipont A, VAN Erck E, Goachet AG, Robert C, Serteyn D.Intense exercise in horses induces an increase of creatine kinase (CK) and stimulation of neutrophils which release the strong oxidant enzyme, myeloperoxidase (MPO) into the blood. It is not known whether active MPO is found in equine muscles and whether oxidant activity of neutrophils could affect muscular tissues and mitochondrial activity. Objective: Specific immuno-extraction followed by enzymatic detection (SIEFED) methods will be employed for the first time to assess both the normal range of MPO and mitochondrial complex I (MCI) activities in equine muscular microbiopsies and to study th...
Bergh A, Nordlöf H, Essén-Gustavsson B.Neuromuscular electrical stimulation (NMES) is used to increase or maintain muscle strength during rehabilitation. Human studies investigating different protocols show that some treatments induce changes in muscle characteristics. Despite the frequent use of NMES in horses, no studies have been published describing its efficacy. Objective: To investigate the effects of a NMES protocol on equine fibre types and areas, glycogen concentrations and enzyme activities. Methods: NMES was administrated to m. gluteus medius and m. longissimus dorsi, on one side of 6 healthy Standardbred horses. The con...
Serteyn D, Sandersen C, Lejeune JP, de la Rebière de Pouyade G, Ceusters J, Mouithys-Mickalad A, Niesten A, Fraipont A, van Erck E, Goachet AG....Intense physical exercise can induce the degranulation of neutrophils leading to an increase in plasma concentration of the neutrophil marker enzymes myeloperoxidase (MPO) and elastase (ELT). These enzymes have pro-oxidative and pro-inflammatory properties and may play a role in the exercised-induced muscular damage. Objective: To measure MPO and ELT concentrations in plasma and muscles of endurance horses and to correlate them to the extent of exercise-induced muscular damage. Methods: Seven endurance horses qualified on 120 km races were tested in this study. Neutrophil count, serum creatine...
Revold T, Ihler CF, Karlström K, Larsen S, Essén-Gustavsson B.The trotting speed of Norwegian-Swedish Coldblooded Trotters (NSCTs) is, although inferior to Standardbred speeds, gradually increasing. This development is mainly attributed to breeding progresses. Characteristics of the middle gluteal muscle have recently been described in a small number of these horses but the actual spread in muscle parameters within the population is unknown. Objective: To describe the characteristics of the middle gluteal muscle and their naturally occurring variability in young NSCT horses and investigate possible association with body size, individual breeding index an...
De Mello Costa MF, Anderson GA, Davies HM, El-Hage CM, Slocombe RF.Investigate angiotensin converting enzyme (ACE) activity in equine plasma as a predictor of performance in endurance competitions and the effect of endurance exercise on ACE activity. Objective: Precompetition values of ACE activity in equine blood are correlated with performance results and with heart rates pre- and post competition used as indicators of fitness. Endurance exercise increases ACE activity. Methods: Nineteen horses participating in an 80 km endurance competition had venous blood samples collected before and after the ride. ACE activity and total protein were measured in the blo...
Megid Gomaa NA, Köller G, Fritz Schusser G.To measure serum alcohol dehydrogenase (ADH) activity in horses with acute intestinal obstruction and to determine the diagnostic and prognostic utility of this analyte. Methods: Prospective observational study. Methods: University Veterinary Hospital. Methods: Thirty healthy horses (control group) and 77 horses with acute intestinal obstruction, including 36 horses with nonstrangulating obstruction (23 with left ventral colon impaction and 13 with left dorsal displacement [G1], 22 with small intestinal strangulation [G2], and 19 with colon torsion [G3]). Methods: Serum ADH activity was assaye...
Kareskoski M, Sankari S, Johannisson A, Kindahl H, Andersson M, Katila T.Semen jets in the stallion's ejaculate differ in both the biochemical composition of seminal plasma (SP) and in sperm concentration, forming sperm-rich fractions (HIGH) and sperm-poor fractions (LOW). This study examined (i) the association of the levels of selected components of SP [alkaline phosphatase (AP), acid phosphatase (ACP), Na(+), Cl(-), K(+), Ca, Mg and prostaglandin E(2)] with semen quality, sperm longevity and fertility; (ii) the effects of the presence of SP on sperm survival during cooled storage; (iii) the differences in the composition of SP between sperm-rich and sperm-poor e...
DiMaio Knych HK, Arthur RM, Taylor A, Moeller BC, Stanley SD.Dantrolene is a skeletal muscle relaxant used commonly in performance horses to prevent exertional rhabdomyolysis. The goal of the study reported here was to begin to characterize cytochrome P450-mediated metabolism of dantrolene in the horse and describe the pharmacokinetics of the compound, formulated as a capsule or a compounded paste formulation, following oral administration. Dantrolene is rapidly metabolized to 5-hydroxydantrolene both in vivo and in vitro. Preliminary work with equine liver microsomes suggest that two enzymes are responsible for the metabolism of dantrolene, as evidence...
Hofmaier F, Hauck SM, Amann B, Degroote RL, Deeg CA.Autoimmune uveitis is a sight-threatening disease in which autoreactive T cells cross the blood-retinal barrier. Molecular mechanisms contributing to the loss of eye immune privilege in this autoimmune disease are not well understood. In this study, the authors investigated the changes in the matrix metalloproteinase network in spontaneous uveitis. Methods: Matrix metalloproteinase (MMP) MMP2, MMP9, and MMP14 expression and tissue inhibitor of metalloproteinase (TIMP)-2 and lipocalin 2 (LCN2) expression were analyzed using Western blot quantification. Enzyme activities were examined with zymog...
García BM, Moran AM, Fernández LG, Ferrusola CO, Rodriguez AM, Bolaños JM, da Silva CM, Martínez HR, Tapia JA, Peña FJ.Cryopreservation introduces extreme temperature and osmolality changes that impart lethal and sublethal effects on spermatozoa. Additionally, there is evidence that the osmotic stress induced by cryopreservation causes oxidative stress to spermatozoa. The main sources of reactive oxygen species in mammalian sperm are the mitochondria. In view of this, the aim of our study was to test whether or not osmotic stress was able to induce mitochondrial damage and to explore the osmotic tolerance of the mitochondria of stallion spermatozoa. Ejaculates from 7 stallions were subjected to osmolalities ra...
Turk R, Habuš J, Flegar-Meštrić Z, Svetina A, Mojčec V, Perkov S, Belić M, Starešina V, Turk N.The aim of the study was to investigate the effect of infection with Leptospira spp. in horses on activities of platelet-activating factor acetylhydrolase (PAF-AH) and paraoxonase-1 (PON1) considering the anti-inflammatory/anti-oxidative properties of both enzymes. A total of 63 sport and leisure horses' sera were chosen among those routinely serologically examined on leptospirosis during the year 2009 in Croatia. Sera were divided into three groups according to the estimated level of antibody titre against Leptospira spp; group 1: sera serologically negative to leptospirosis (antibody titre<5...
Costa MF, Davies HM, Anderson GA, Slocombe RF.Studies in man have shown a correlation between Angiotensin I-converting enzyme (ACE) genetic polymorphisms, ACE activity in the blood and superior athletic performance in sports requiring endurance. It has been hypothesised that the same correlation occurs in horses. There is no information in the literature concerning the effects of training on ACE activity in equine plasma. Objective: Exercise training influences the activity of circulating ACE and the response observed is dependent on the exercise protocol. Methods: Thirteen horses of mixed breeds were randomly allocated 2 different traini...
Tang X, Sayre LM, Tochtrop GP.Cytochrome c is a key mitochondrial respiratory protein that is particularly susceptible to modification during oxidative stress. The nature of this susceptibility is linked to the mitochondrial membrane being rich in esterified linoleic acid, which predisposes this organelle to the formation of lipid peroxidation products such as 4-hydroxy-2-(E)-nonenal (4-HNE). To better understand the nature of cytochrome c modification by 4-HNE, we initiated an in vitro study utilizing a combination of MALDI-TOF mass spectrometry, LC-ESI-MS/MS and isotope labeling to monitor 4-HNE modification of cytochrom...
Wong JK, Tang FP, Wan TS.The study of the metabolism of drugs, in particular steroids, by both in vitro and in vivo methods has been carried out in the authors' laboratory for many years. For in vitro metabolic studies, the microsomal fraction isolated from horse liver is often used. However, the process of isolating liver microsomes is cumbersome and tedious. In addition, centrifugation at high speeds (over 100 000 g) may lead to loss of enzymes involved in phase I metabolism, which may account for the difference often observed between in vivo and in vitro results. We have therefore investigated the feasibility of us...
Costa MF, Carmona AK, Alves MF, Ryan TM, Davies HM, Anderson GA, Slocombe RF.Angiotensin-I converting enzyme (ACE) is a key regulator of blood pressure, electrolytes and fluid homeostasis through conversion of angiotensin I into angiotensin II. Recently, a genetic polymorphism of the ACE gene, which accounts for 47% of the variation of ACE activity in blood, has been advocated as a biomarker of athletic aptitude. Different methods of analysis and determination of ACE activity in plasma have been used in human and equine research without a consensus of a "gold standard" method. Different methods have often been used interchangeably or cited as being comparable in the ex...
Almeida J, Conley AJ, Mathewson L, Ball BA.In the mammalian testis, Leydig cells are primarily responsible for steroidogenesis. In adult stallions, the major endocrine products of Leydig cells include testosterone and estrogens. 3β-hydroxysteroid dehydrogenase/Δ(5)-Δ(4)-isomerase (3βHSD) and 17α-hydroxylase/17,20-lyase (P450c17) are two key steroidogenic enzymes that regulate testosterone synthesis. Androgens produced by P450c17 serve as substrate for estrogen synthesis. The aim of this study was to investigate localization of the steroidogenic enzymes P450c17, 3βHSD, and P450arom and to determine changes in expression during dev...
de Laat MA, Kyaw-Tanner MT, Nourian AR, McGowan CM, Sillence MN, Pollitt CC.Metalloproteinases have been implicated in the pathogenesis of equine laminitis and other inflammatory conditions, through their role in the degradation and remodelling of the extracellular matrix environment. Matrix metalloproteinases (MMPs) and their inhibitors are present in normal equine lamellae, with increased secretion and activation of some metalloproteinases reported in horses with laminitis associated with systemic inflammation. It is unknown whether these enzymes are involved in insulin-induced laminitis, which occurs without overt systemic inflammation. In this study, gene expressi...
Klein C, Scoggin KE, Troedsson MH.Establishment of pregnancy is critically dependent upon a precisely orchestrated embryo-maternal interaction leading to a receptive uterine environment. The up-regulation of the interferon-stimulated protein 15 kDa (ISG15) during pregnancy has been described in various species and has been hypothesized to be part of the molecular repertoire that makes the uterus receptive to conceptus development. In the current study, the expression of ISG15 and enzymes involved in ISG15ylation was examined at the mRNA and protein level in equine endometrium at Day 14 of the luteal phase and at Day 14 and 50 ...
Oddsdóttir C, Riley SC, Leask R, Shaw DJ, Aurich C, Palm F, Fowden AL, Ricketts SW, Watson ED.During late gestation in the mare, rapid fetal growth is accompanied by considerable placental growth and further invasion of the endometrium by microvilli. This growth requires extensive remodeling of the extracellular matrix (ECM). In early pregnancy, we know that matrix metalloproteinase (MMP)-9 and -2 are involved in the endometrial invasion during endometrial cup formation. The present study investigated whether MMPs are found in fetal fluids later in gestation and during parturition, and if there was a difference in their activities between normal and preterm delivery. Amniotic fluids we...
Underwood C, Southwood LL, Walton RM, Johnson AL.To determine: (1) changes in blood ammonia, bile acid (BA), bilirubin, triglyceride, and glucose concentrations and liver enzyme activities in perioperative colic patients and (2) the association between these laboratory findings and short-term survival. Methods: Prospective observational clinical study. Methods: Thirty-two adult horses undergoing exploratory celiotomy for colic. Methods: None. Results: Blood samples were collected preoperatively and at 24-36 and 72-84 hours postoperatively and analyzed for blood ammonia, BA, bilirubin, triglyceride, and glucose concentrations and sorbitol deh...
van den Hoven R, Bauer A, Hackl S, Zickl M, Spona J, Zentek J.In this preliminary study, time-dependent changes in plasma CK and AST activity, tyrosine (Tyr), 3-methyl-histidine (3mHis), glucose and lactate concentrations were analysed in nine horses under two different conditions. Furthermore, intramuscular concentrations of Tyr, 3mHis and activities of cathepsin B, acid phosphatase (ACP), glucose-6-phosphate dehydrogenase (G6PDH) and mRNA expression of ubiquitin were determined at the same time. After studying the effects of exercise alone, the effects of exercise and feeding of an experimental protein/amino acid (AA) supplement were analysed. Horses w...
Schmitz A, Demmel S, Peters LM, Leeb T, Mevissen M, Haase B.Cytochrome P450 enzymes (CYP450s) represent a superfamily of haem-thiolate proteins. CYP450s are most abundant in the liver, a major site of drug metabolism, and play key roles in the metabolism of a variety of substrates, including drugs and environmental contaminants. Interaction of two or more different drugs with the same enzyme can account for adverse effects and failure of therapy. Human CYP3A4 metabolizes about 50% of all known drugs, but little is known about the orthologous CYP450s in horses. We report here the genomic organization of the equine CYP3A gene cluster as well as a compara...
Ascenzi P, Ciaccio C, Sinibaldi F, Santucci R, Coletta M.Upon interaction with bovine heart cardiolipin (CL), horse heart cytochrome c (cytc) changes its tertiary structure disrupting the heme-Fe-Met80 distal bond, reduces drastically the midpoint potential out of the range required for its physiological role, binds CO and NO with high affinity, and displays peroxidase activity. Here, the effect of CL on peroxynitrite isomerization by ferric cytc (cytc-Fe(III)) is reported. In the absence of CL, hexa-coordinated cytc does not catalyze peroxynitrite isomerization. In contrast, CL facilitates cytc-Fe(III)-mediated isomerization of peroxynitrite in a d...
Morrissey NK, Bellenger CR, Ryan MT, Baird AW.To measure the expression of cyclooxygenase-2 (COX-2) mRNA in gastric biopsy specimens serially obtained from horses before, during, and after an 8-day intermittent feed-deprivation trial and to investigate the mucosal location of COX-2. Methods: 9 mixed-breed horses for retrieval of gastric biopsy specimens and 16 additional horses for immunohistochemical analysis. Methods: Gastric biopsy specimens were obtained from 6 horses; 3 of these horses and 3 more participated in an intermittent feed-deprivation trial 9 weeks later. A quantitative PCR assay was used to determine the amount of COX-2 mR...
Bach BC, Leal DB, Ruchel JB, Souza Vdo C, Maboni G, Dal Pozzo M, Schlemmer KB, Alves SH, Santurio JM.NTPDase (EC 3.6.1.5) occurs in lymphocytes and plays an important role in immune function, in that hydrolyzes extracellular nucleoside tri- and/or diphosphates to form AMP. Pythium insidiosum causes the disease pythiosis, a pyogranulomatous disease of horses, dogs, cattle, cats and humans. Most antifungal drugs are ineffective against this pathogen, and immunotherapy, a treatment approach that relies on the injection of P. insidiosum antigen, has been successfully used in humans and horses to manage this disease. In this study, we investigated NTPDase activity in lymphocytes from rabbits inocu...
Ascenzi P, Santucci R, Coletta M, Polticelli F.Ligand binding to the heme distal side is a paradigm of heme-protein biochemistry, the proximal axial ligand being in most cases a His residue. NO binds to the ferrous heme-Fe-atom giving rise to hexa-coordinated adducts (as in myoglobin and hemoglobin) with His and NO as proximal and distal axial ligands, respectively, or to penta-coordinated adducts (as in soluble guanylate cyclase) with NO as the axial distal ligand. Recently, the ferrous derivative of Alcaligenes xylosoxidans cytochrome c' (Axcyt c') and of cardiolipin-bound horse heart cytochrome c (CL-hhcyt c) have been reported to bind ...
Honnens A, Weisser S, Welter H, Einspanier R, Bollwein H.The objective of this study was to investigate the relationships between uterine perfusion and estrogen, progesterone and the uterine nitric oxide synthase (NOS) system in five trotter mares during the estrous cycle. Color Doppler sonography for measurement of uterine blood flow and collection of blood for determination of plasma estrogen and progesterone concentrations were performed on days 0 (= ovulation), 1, 5, 11 and 15 and daily during estrus (days -1 to -4) of one estrous cycle; endometrial biopsy collection for mRNA expression analysis of NOS and estrogen receptors was performed on day...
Doré M.Cyclooxygenase (COX; also known as prostaglandin endoperoxide synthase) is a key enzyme in the biochemical pathway leading to the synthesis of prostaglandins. A large amount of epidemiological and experimental evidence supports a role for COX-2, the inducible form of the enzyme, in human tumorigenesis, notably in colorectal cancer. COX-2 mediates this role through the production of PGE(2) that acts to inhibit apoptosis, promote cell proliferation, stimulate angiogenesis, and decrease immunity. Similarly, COX-2 is believed to be involved in the oncogenesis of some cancers in domestic animals. H...
Koepf EK, Burtnick LD.Horse plasma gelsolin labelled with benzophenone-4-isothiocyanate can be photochemically cross-linked to rabbit cardiac tropomyosin. The cross-linking proceeds with greater efficiency in calcium-containing buffers. Further evidence for interaction between these proteins is provided by retention of fluorescently labelled gelsolin on tropomyosin-agarose affinity columns and by the ability of tropomyosin to cause an increase in the fluorescence intensity of gelsolin labelled with fluorescein-5-isothiocyanate. Both of these effects require the presence of calcium ions.
van den Hoven R, Bauer A, Hackl S, Zickl M, Spona J, Zentek J.In this preliminary study, time-dependent changes in plasma CK and AST activity, tyrosine (Tyr), 3-methyl-histidine (3mHis), glucose and lactate concentrations were analysed in nine horses under two different conditions. Furthermore, intramuscular concentrations of Tyr, 3mHis and activities of cathepsin B, acid phosphatase (ACP), glucose-6-phosphate dehydrogenase (G6PDH) and mRNA expression of ubiquitin were determined at the same time. After studying the effects of exercise alone, the effects of exercise and feeding of an experimental protein/amino acid (AA) supplement were analysed. Horses w...
Larsson P, Persson E, Tydén E, Tjälve H.Horses may be exposed to aflatoxin B(1) (AFB(1)) via inhalation of mouldy dust, leading to high exposure of olfactory and respiratory tissues. In the present study the metabolic activation of AFB(1) was examined in olfactory and respiratory tissues in horse. The results showed covalent binding of AFB(1)-metabolites in sustentacular cells and cells of Bowman's glands in the olfactory mucosa, in some cells of the surface epithelium of nasal respiratory, tracheal, bronchial and bronchiolar mucosa and in some glands in these areas. Immunohistochemistry revealed that cells expressing proteins react...
Kline KH, Bechtel PJ.1. Cross sections from the middle of the gluteus medius were removed from 10 adult horses and used to evaluate changes in histochemically determined muscle fiber type and biochemically determined metabolic enzyme activities as a function of sample depth. 2. Muscle fiber types determined using histochemical methods for myosin ATPase (pH 9.4) and succinic dehydrogenase (SDH) activity indicated percent fast-twitch glycolytic (FG) muscle fibers decreased and slow-twitch oxidative (SO) fibers increased as a function of increasing sampling depth. 3. Percent histochemically determined fast-twitch oxi...
Nishita T, Matsushita H.1. Carbonic anhydrase III (CA-III) from different mammalian species (horse, cow, dog, cat, rat and rabbit) has been analyzed by the immunodiffusion technique with anti-equine CA-III serum. 2. Immunodiffusion demonstrated the absence of cross-reactivity between isozyme CA-I, CA-II, and CA-III. 3. Cross-reactions were observed between the CA-III from all the species examined except the rabbit. 4. Molecular weights and isoelectric points of CA-III from different species were determined by Western blotting.
Hoffmann WE, Baker G, Rieser S, Dorner JL.Effects of induced cholestasis and hepatocellular necrosis and of fasting on serum biochemical constituents including bile acids, IgA, bilirubin, alkaline phosphatase, gamma-glutamyltransferase (GGT), arginase, and the clearance of sodium sulfobromophthalein were studied in 4 groups of equids. The reference value for serum bile acids, as determined by an enzymatic colorimetric procedure for horses and ponies was 5.94 +/- 2.72 mumol/L, there being no statistical difference for horses and ponies. Sample collection at time of feeding had no effect on serum bile acid concentration. Seemingly, seru...
Braun JP, Benard P, Burgat V, Rico AG.In domestic animals, Gamma Glutamyl Transferase is mainly in the kidneys, the pancreas and the intestine; its liver activity is relatively high in cows, horses, sheep and goats and very low in dogs, cats and birds. The use of plasma reference values can help to interpret the variations of serum GGT mainly in hepatobiliary diseases of cattle, sheep, goats and cholestatic disorders of dogs. Urinary GGT is a good test of kidney toxic damage.
Fotschki J, Wróblewska B, Fotschki B, Kalicki B, Rigby N, Mackie A.Horse milk is a valuable raw material and a very attractive alternative for scientific research to address the issue of cow milk (CM) allergy due to its protein profile. A decrease in immunoreactive properties can be achieved by thermal, enzymatic, and hydrolytic processing. Therefore, the aim of this study was to explore the possibility of reducing the immunoreactivity of horse milk proteins by microbial transglutaminase (TG) polymerization. To determine how TG linking alters immunoreactivity under simulated digestion of the examined milk, analyses were performed before, during, and after dig...
Ward TL, Valberg SJ, Lear TL, Guérin G, Milenkovic D, Swinburne JE, Binns MM, Raudsepp T, Skow L, Chowdhary BP, Mickelson JR.Comparative biochemical and histopathological data suggest that a deficiency in the glycogen branching enzyme (GBE) is responsible for a fatal neonatal disease in Quarter Horse foals that closely resembles human glycogen storage disease type IV (GSD IV). Identification of DNA markers closely linked to the equine GBE1 gene would assist us in determining whether a mutation in this gene leads to the GSD IV-like condition. FISH using BAC clones as probes assigned the equine GBE1 gene to a marker deficient region of ECA26q12-->q13. Four other genes, ROBO2, ROBO1, POU1F1, and HTR1F, that flank GB...
Ball BA, Gravance CG, Wessel MT, Sabeur K.A testis-specific isoform of angiotensin-converting enzyme (ACE) has been identified in a number of mammalian species. The purpose of this study was to characterize the activity of ACE in equine spermatozoa, seminal plasma, and testis. Activity of ACE was determined in seminal plasma, ejaculated and epididymal spermatozoa from mature stallions as well as from pre- and postpubertal testis. The effect of addition of angiotensin II on equine sperm motility was also evaluated. The activity of ACE in detergent extracted sperm plasma membrane was approximately 13-fold higher than that detected in se...
von Fellenberg R, Kohler L, Grünig G, Pellegrini A.Neutral neutrophil protease, elastase activities, and cytosol protease inhibitors of these enzymes of horses and man were compared. Human neutrophils had 5 times the elastase activity of equine neutrophils, and neutral protease activity was approximately 50% greater in human neutrophils than that in equine neutrophils. Cytosol inhibitors for elastase and neutral proteases were not found in human neutrophils, whereas large amounts were found in equine neutrophils. Using fibrinogen-agarose electrophoresis, 4 cytosol inhibitors of different enzyme specificities were detected. These cytosol inhibi...
Zhang Z, Gao X, Dong W, Huang B, Wang Y, Zhu M, Wang C.Equines and ruminants have evolved as grazing herbivores with specialized gastrointestinal tracts capable of utilizing a wide range of fibrous feeds. In China, agricultural by-products, including corn straw, wheat straw, peanut vine, wheat husk, rice husk, and grass hay, have been extensively included in both equine and ruminant diets. These plant materials, which are composed predominantly of cellulose, hemicellulose, noncellulosic polysaccharides, and lignin, are largely undegradable by equines and ruminants themselves. Their breakdown is accomplished by communities of resident microorganism...
Arai T, Takahashi M, Araki K, Washizu T.The activities of the enzymes related to the malate-aspartate shuttle, which convert cytosolic NADH into mitochondrial NADH, were measured in red and white blood cells from thoroughbred horses undergoing continuous training (race horses) and compared with those in blood cells from riding horses. The activities of malate dehydrogenase (MDH), a rate-limiting enzyme for the malate-aspartate shuttle, were significantly elevated in the white blood cells (WBC) from race horses compared with those from riding horses. There were no significant differences in the activities of the enzymes in the red bl...
Strubbe DT, Brooks DE, Schultz GS, Willis-Goulet H, Gelatt KN, Andrew SE, Kallberg ME, MacKay EO, Collante WR.Ulcerative keratitis is a common and potentially blinding ocular disease of horses, capable of progressing to corneal perforation in as little as 24 h. This rapid stromal degeneration is mediated in part by exogenous and endogenous proteinases. We measured and compared the concentrations of two matrix metalloproteinases (MMP-2 and MMP-9) and a serine proteinase (neutrophil elastase) present in the precorneal tear film of normal horses and horses with rapidly progressing ulcerative keratitis. Precorneal tear film samples were collected from 23 ulcerated and 21 unaffected eyes of 23 horses with ...
Klein C, Troedsson M.During the second and third week of pregnancy, the equine conceptus is covered by an acellular glycoprotein capsule. This capsule contains glycoproteins resembling those of the mucin family with sialic acid making up a high proportion of the carbohydrate. Coinciding with conceptus fixation, a marked decline in sialic acid content of the capsule occurs, which has been proposed to contribute to cessation of conceptus mobility. Herein, we describe the expression of neuraminidase 2 (NEU2) by pre-implantation stages of equine conceptus development. NEU2 transcript abundance was examined in conceptu...
Bolfă PF, Leroux C, Pintea A, Andrei S, Cătoi C, Taulescu M, Tăbăran F, Spînu M.This study assesses the impact of equine infectious anaemia virus (EIAV) infection on the oxidant/antioxidant equilibrium of horses. Blood samples from 96 Romanian horses aged 1-25 years, were divided into different groups according to their EIAV-infection status, age, and time post-seroconversion. The effect of infection on oxidative stress was estimated by measuring enzymatic antioxidants (superoxide dismutase [SOD], glutathione peroxidase [GPx] and catalase), non-enzymatic antioxidants (uric acid and carotenoids), and lipid peroxidation (malondialdehyde [MDA]). Infection modified the oxidan...
Jouglin M, Robert C, Valette JP, Gavard F, Quintin-Colonna F, Denoix JM.Early detection of osteoarthritis in horses represents a challenge for equine practitioners. Several biological markers have been implicated in the pathological processes involved in articular cartilage destruction. To further document cartilage matrix proteases production, synovial fluid was collected from 14 horses (90 joints) before they were subjected to euthanasia. Growth macroscopic examination of the joints gave information on cartilage alterations. Samples were analyzed for matrix metalloproteinase (MMPs) activities by gelatin zymography and tumor necrosis factor alpha (TNF-alpha) cyto...
Singh UK, Patel R.In vitro refolding of denatured protein and the influence of the alkyl chain on the refolding of a protein were tested using long chain imidazolium chloride salts, 1-methyl-3-octylimidazolium chloride [Cmim][Cl], and 1-decyl-3-methylimidazolium chloride [Cmim][Cl]. The horse heart cytochrome c (h-cyt c) was denatured by urea and guanidinium hydrochloride (GdnHCl), as well as by base-induced denaturation at pH 13, to provide a broad overview of the overall refolding behavior. The variation in the alkyl chain of the ionic liquids (ILs) showed a profound effect on the refolding of denatured h-cyt...
Shihadih DS, Harris TR, Kodani SD, Hwang SH, Lee KSS, Mavangira V, Hamamoto B, Guedes A, Hammock BD, Morisseau C.The veterinary pharmacopeia available to treat pain and inflammation is limited in number, target of action and efficacy. Inhibitors of soluble epoxide hydrolase (sEH) are a new class of anti-inflammatory, pro-resolving and analgesic drugs being tested in humans that have demonstrated efficacy in laboratory animals. They block the hydrolysis, and thus, increase endogenous concentrations of analgesic and anti-inflammatory signaling molecules called epoxy-fatty acids. Here, we screened a library of 2,300 inhibitors of the sEH human against partially purified feline, canine and equine hepatic sEH...
Breidenbach A, Fuhrmann H, Deegen E, Lindholm A, Sallmann HP.The enzymatic fundamentals of lipid metabolism of equine have not been thoroughly investigated at this point in time. It is still unclear why ponies in contrast to horses may become hyperlipaemic when coming negative energy balance. In this study, the activities of the triglyceride-cleaving key enzymes of ponies are large bred horses were investigated in order to obtain insight into the aetiology of the syndrome. The objective of the study was to measure the activities of hormone-sensitive lipase (HSL), lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) in ponies and horses in ex ...
Ghasemi S, Sardari K, Mirshokraei P, Hassanpour H.Application of synthetic matrix metalloproteinases (MMPs) inhibitors, such as doxycycline is one of the possible therapeutic options for osteoarthritis. However, little is known about the protective mechanism of doxycycline in equine models on MMPs inhibitors as well as on serum amyloid A (SAA) gene expression. This study investigated the effects of doxycycline on mRNA expression of MMP-1, MMP-2, MMP-9, MMP-13, and SAA of equine fibroblast-like synoviocytes (FLSs). The FLSs were established from synovial fluids of clinically normal metacarpophalangeal joints of 6 skeletally mature horses. The ...
Larsdotter S, Nostell K, von Euler H.Serum thymidine kinase (sTK) activity is a tumour marker used as a prognostic indicator for lymphoma in humans, dogs and cats. The aim of this study was to evaluate the clinical utility of sTK as a biomarker for lymphoma in horses. Serum samples were collected from clinically normal horses (n = 37), horses with lymphoma (n = 23), horses with non-haematopoietic neoplasia (n = 9) and horses with inflammatory disease (n = 14). sTK was measured using a radioenzyme assay. A reference cut-off value of <2.7 U/L (mean + 2 standard deviations, SDs) was established using data fro...
Saudek V, Wormald MR, Williams RJ, Boyd J, Stefani M, Ramponi G.Nuclear magnetic resonance spectra of acylphosphatase were searched for signs of beta-structure, i.e. characteristic nuclear Overhauser enhancement patterns displayed in the two-dimensional spectra, typical chemical shifts, coupling constants and slow 2H-H exchange. The results provided identification of the main-chain resonances of amino acid residues involved in the beta-structure. The full sequential assignment of this region was gained by identification of some amino acid spin systems and their alignment with the primary sequence. The assignment of the side-chains was virtually completed s...
Visser MB, Pollitt CC.The role of matrix metalloproteases (MMPs) and the timeline of proteolysis during laminitis development are incompletely understood. Objective: To determine the temporal progression of selected MMPs and protease regulators during laminitis development. Methods: Five clinically normal Standardbred horses received, via nasogastric intubation, an oligofructose (OF) bolus (10 g/kg bwt). Laminitis induction proceeded for 48 h followed by euthanasia. Lamellar biopsies were obtained prior to dosing and at intervals during the treatment period for analysis (12, 18, 24, 30 and 36 h and at 48 h followin...
Price JS, Jackson B, Eastell R, Wilson AM, Russell RG, Lanyon LE, Goodship AE.In this study we tested the hypothesis that exercise induces an adaptive response in the developing skeleton which may be monitored in vivo by measuring biochemical markers of bone metabolism. The effects of exercise on two biochemical markers of bone formation were determined; the carboxy-terminal propeptide of type I procollagen (PICP), and the bone-specific isoenzyme of alkaline phosphatase (BAP), and one putative marker of resorption, the pyridinoline crosslinked telopeptide domain of type I collagen (ICTP). All three markers were measured for a year in 2-year-old thoroughbred horses exerc...
Davenport CL, Boston RC, Richardson DW.To investigate the effects of enrofloxacin and magnesium deficiency on explants of equine articular cartilage. Methods: Articular cartilage explants and cultured chondrocytes obtained from adult and neonatal horses. Methods: Full-thickness explants and cultured chondrocytes were incubated in complete or magnesium-deficient media containing enrofloxacin at concentrations of 0, 1, 5, 25, 100, and 500 microg/ml. Incorporation and release of sulfate 35S over 24 hours were used to assess glycosaminoglycan (GAG) synthesis and degradation. An assay that measured binding of dimethylmethylene blue dye ...
Castro Martins M, Peffers MJ, Lee K, Rubio-Martinez LM.Intra-articular administration of stanozolol has shown promising results by improving the clinical management of lameness associated with naturally-occurring osteoarthritis (OA) in horses, and by decreasing osteophyte formation and subchondral bone reaction in sheep following surgically induced OA. However, there is limited evidence on the anti-inflammatory and modulatory properties of stanozolol on articular tissues. The objective of the current study was to evaluate the effects of stanozolol on chondrocyte viability and gene expression in normal equine chondrocytes and an inflammatory in vit...
Zylicz-Stachula A, Zolnierkiewicz O, Jasiecki J, Skowron PM.Genomics and metagenomics are currently leading research areas, with DNA sequences accumulating at an exponential rate. Although enormous advances in DNA sequencing technologies are taking place, progress is frequently limited by factors such as genomic contig assembly and generation of representative libraries. A number of DNA fragmentation methods, such as hydrodynamic sharing, sonication or DNase I fragmentation, have various drawbacks, including DNA damage, poor fragmentation control, irreproducibility and non-overlapping DNA segment representation. Improvements in these limited DNA scissi...
Gardner RB, Nydam DV, Mohammed HO, Ducharme NG, Divers TJ.The purpose of this study was to test the hypothesis that horses with right dorsal displacement of the large colon (RDDLC) have elevations in serum gamma glutamyl transferase (GGT) activity when compared with horses with left dorsal displacement of the large colon (LDDLC). Medical records from 37 horses with RDDLC and 48 horses with LDDLC were reviewed. Horses were included for study if the RDDLC or LDDLC was confirmed by exploratory laparotomy or postmortem examination and if a serum GGT measurement was obtained within 24 hours before surgery. The proportion of horses with GGT activity within...
Dworschack R, Tarr G, Plapp BV.A single amino group in horse liver alcohol dehydrogenase was modified with methyl(14C)acetimidate by a differential labeling procedure. Lysine residues outside the active site were modified with ethyl acetimidate while a lysine residue in the active site was protected by the formation of an enzyme-NAD+-pyrazole complex. After the protecting reagents were removed, the enzyme was treated with methyl(14C)acetimidate. Enzyme activity was enhanced 13-fold as 1.1 (14C)acetimidyl group was incorporated per active site. A labeled peptide was isolated from a tryptic-chymotryptic digest of the modified...
