Hepatic function in horses involves the liver's role in various physiological processes, including metabolism, detoxification, and the synthesis of essential proteins and bile. The liver is responsible for processing nutrients absorbed from the digestive tract, converting them into energy, and storing them for future use. It also plays a vital role in detoxifying the blood by metabolizing drugs and toxins. Additionally, the liver synthesizes proteins necessary for blood clotting and immune function, as well as producing bile to aid in the digestion and absorption of fats. This page aggregates peer-reviewed research studies and scholarly articles that explore the liver's functions, its regulation, and its impact on equine health.
Dosi M, Scott L, Payne H, Poldy J, Keen J, McGorum B, Malbon A, Morgan R.Hyperinsulinaemia (HI) is an important feature of Equine Metabolic Syndrome (EMS). It has been suggested that reduced hepatic clearance of insulin contributes to HI, particularly in humans affected by metabolic dysfunction-associated steatotic liver disease (MASLD). Objective: In obese horses with HI, insulin clearance is impaired and associated with MASLD. Methods: Tissue samples were collected at post-mortem from clinically well-characterized horses with HI (n = 13; basal insulin > 20 mIU/l) and without HI (control; n = 20). Methods: Retrospective observational study. Molecular d...
Slavik K, Bender S, Sharkey L, Nolen-Walston R.Renal lipidosis is a well-documented histologic finding in humans and small animals with renal and metabolic disorders, but it is not well described in equids. Objective: To describe the signalment, clinicopathologic indices, and postmortem findings of equids with a histologic diagnosis of both hepatic and renal lipidosis (HL + RL) and compare them to cases with hepatic lipidosis only (HL). Methods: Equids with necropsy findings of renal or hepatic lipidosis (state diagnostic lab) between 2008 and 2022. Methods: Retrospective case-control study. Signalment, history, necropsy diagnosis, and...
Yu R, Jusko WJ.This study assesses the pharmacokinetics (PK) of published methylprednisolone (MPL) data in horses following intra-articular (IA) administration of MPL acetate (MPA) and the associated adrenal suppression. The concentrations of MPL/MPA in synovial fluid, blood, and urine, as well as hydrocortisone (HC) in plasma, were digitized from multiple sources in the literature. A minimal physiologically based pharmacokinetic model and a linked indirect response model with a circadian rhythm baseline were applied. Concentrations of MPA in joints followed a triexponential decay, converting to MPL. The cle...
Al-Khaldi KO, Al-Ruzaiqi KH, Babji AS, Lim SJ, Sadiq MB, Yimer N.Exercise-induced oxidative stress and inflammation adversely affect the health and performance of athletic horses. This study aimed to evaluate the safety of edible bird's nest (EBN) supplementation and its potential anti-inflammatory and immunomodulatory effects in Arabian race stallions during exercise. Key objectives included assessing EBN's impact on hepatic and renal function, hematological profiles, and sialic acid (SA) levels. Unassigned: Two experiments were conducted on 18 Arabian stallions. In Experiment 1, six healthy stallions were divided into control (n = 2) and EBN-supplemented ...
Iranmanesh M, Sato AF, Tenney W, Brinker EJ, Cortez K, Mazan M.A 1-year-old Miniature Horse filly was presented for chronic lethargy and hyporexia. Elevated liver enzymes, bile acids, and ammonia were noted on bloodwork. The primary differential diagnosis was a portosystemic shunt (PSS). Three-phase computed tomographic angiography findings were consistent with a transhepatic portosystemic shunt. Percutaneous liver biopsy confirmed severe diffuse hepatic changes, most likely due to chronic pyrrolizidine alkaloid toxicosis, and medical management was elected. Based on an extensive literature review, this is the first report of a transhepatic portosystemic ...
Alshammari A, Gattan HS, Marzok M, Salem M, Al-Jabr OA, Selim A.Fasciola hepatica is a trematode parasite that affects wide range of mammalian hosts including horses. There are no epidemiological data on fasciolosis in Egyptian horses. Hence, the present study aimed to evaluate the seroprevalence of F. hepatica in horses using ELISA as well as assess the associated risk factors for fasciolosis infection. A total of 400 sera samples of horses from three Egyptian governorates were examined. The overall seroprevalence rate in horses was 13% and the disease was more prevalent in Qalubia (14.17%) and Gharbia (16.67%) which are located at Nile Delta. The likelih...
Mercer MA, Davis JL, McKenzie HC, Byron CR, Kelleher ME, Trager L, Cecere TE, Wilson KE, Council-Troche RM, Werre SR.Acetaminophen is used clinically in horses with musculoskeletal pain; however, no studies have been performed in horses with chronic lameness. Objective: To determine the pharmacokinetics, safety and efficacy of chronic dosing of acetaminophen in horses with naturally occurring chronic lameness. Methods: Longitudinal. Methods: Twelve adult horses with chronic lameness were treated with acetaminophen (30 mg/kg PO) every 12 h for 21 days. Plasma concentrations of acetaminophen were analysed on days 7 and 21 via LC-MS/MS and noncompartmental pharmacokinetic analysis. Lameness was evaluated ...
Massányi M, Halo M, Massányi P, Mlyneková E, Greń A, Formicki G, Halo M.Health state of animals undergoing experimental procedures is an important topic nowadays, as even the small changes can influence the outcome of entire outcomes. Main aim of the study was to evaluate the influence of horse training on variety of blood parameters including mineral profile, energy profile, hepatic profile and haematology. In the experiment, the studied group of horses underwent training programme which consisted of transportation, lounging, riding, jumping, racing, treadmill training and shoeing. Blood samples were collected and later evaluated at the beginning, in the middle a...
Tedesco DEA, Guerrini A.Milk thistle, Silybum marianum, is a medicinal plant grown for its bioactive compounds with well-documented antioxidant and hepatoprotective properties. Milk thistle has a well-established pharmacological reputation for treatments of human liver disease, but it is also used in animals. This review summarizes the experimental evidence of milk thistle's effects on animals when administered as silymarin extract (feed additive) or a feed ingredient, if administered as seed or expeller/cake with the seed residue still containing the bioactive components. The use as a feed additive or feed ingredien...
Goodrich EL, Behling-Kelly E.The clinical evaluation of lipid metabolism in equids is often limited to the measurement of total cholesterol and triglyceride concentrations. This provides a limited picture of metabolic state and general health, given the continuous exchange of lipid species between various lipoproteins. Major lipoprotein classes in equids include high-density lipoprotein (HDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and chylomicrons (CM). Unlike large breed horses, donkeys are highly susceptible to hepatic lipidosis. Currently, serum trig...
Maher MA, Ahmad IM.The current study was performed on ten adult Egyptian donkeys of both sexes for anatomical and radiographic studies in addition to six other donkeys for enzymatic, biochemical and statistical analysis. The aim was to illustrate the normal hepatic arterial and biliary distribution using different anatomic techniques and radiographic imaging besides, establishing an accurate laboratory profile specific for donkeys that used as standard indicators for hepatobiliary dysfunction. The right branch of the hepatic artery in donkey forms a curved arch erupting five branches, unlike the left branch that...
Sroka L, Müller C, Hass ML, These A, Aboling S, Vervuert I.Senecio jacobaea contains pyrrolizidine alkaloids that can induce severe hepatic intoxication in horses, either acute when ingested in high amounts or chronic when consumed over a long period. The aim of this study was to determine horses' rejection behaviour towards the presence of Senecio jacobaea in hay when fed ad libitum. We hypothesized that adult horses can sort Senecio jacobaea out of the contaminated hay when hay is fed ad libitum. Six warmblood geldings with a mean (±SD) age of 15 ± 2 years were included. In a randomized study, Senecio jacobaea contaminated hay (5% or 10% con...
RodrÃguez-Pozo ML, Armengou L, Viu J, RÃos J, Jose-Cunilleras E.Peritoneal bile acids concentration (PBAC) has not been previously reported in horses. A case of liver lobe torsion in which increased PBAC was detected prompted us to study PBAC in horses. Objective: (a) To determine a reference range of PBAC in horses; (b) to compare PBAC from horses with either hepatic or gastrointestinal disease and healthy horses and (c) to assess the prognostic and diagnostic values of PBAC. Methods: Prospective case-control. Methods: Prospective observational clinical study. Bile acids concentrations were measured in both plasma and peritoneal fluid in selected clinical...
Mendonça MFF, Pimentel LA, Leal PV, Oliveira Filho JC, Caymmi LG, Silva AWO, Jesus RS, Peixoto TC.This study aimed to describe the first reports of outbreaks of hepatogenous photosensitization in cattle, sheep, and horses caused by spontaneous ingestion of Chamaecrista serpens, as well as to reproduce poisoning in sheep experimentally. Eleven photodermatitis outbreaks of unknown cause occurred in cattle, sheep and horses on nine farms in the semiarid region of Bahia, northeastern Brazil, between July 2017 and July 2020. Cutaneous lesions of photosensitization initiated until one week after the animals were introduced in paddocks invaded by the plant at the beginning of the rainy season. Th...
Jaramillo FM, Piñeros DDV, Corrêa RR, Pogliani FC, Cogliati B, Baccarin RYA.Despite hepatotoxic effects, imidocarb dipropionate is the drug of choice for treatment of equine piroplasmosis. It is important, therefore, to identify adjuvant therapies that may improve the safety of imidocarb dipropionate by reducing the risk of liver damage during its use. The aim of the present study was to evaluate the hepatoprotective and hepatoregulatory effects of treatment with and during administration of imidocarb dipropionate. Methods: Ten healthy horses, seroconverted to by C-ELISA, were treated with 5 mg/kg/day of imidocarb dipropionate for three consecutive days. The study ...
Shibany KA, Pratt SL, Aldurdunji M, Totemeyer S, Paine SW.Horses are exposed to various kinds of medication, however, there are limited determinations of plasma clearance (CL) for the drugs used due to the high cost of equine studies.Many of the CL values generated come from the equine sports industry for determining drug plasma screening limits in the control of medications at the time of competition.The kinetics of omeprazole metabolism were investigated in freshly isolated and cryopreserved equine hepatocytes and hepatic microsomes ( = 3 horses).The V, K and intrinsic clearance (CL) of omeprazole were determined via the substrate depletion me...
DeNotta SL, Divers TJ.The gastrointestinal tract and liver comprise key components of the equine digestive system and together have important functions in metabolism, digestion, absorption, detoxification, and synthesis. Disorders of the gastrointestinal tract and liver are common in clinical practice and can cause a variety of clinical signs. Hematologic and biochemical analysis can be helpful for identifying organ dysfunction, narrowing down the differential diagnostic list, and monitoring progress and response to treatment. This article details hematologic and biochemical tests that are important in the evaluati...
Legere RM, Taylor DR, Davis JL, Bello K, Parker C, Judd RL, Wooldridge AA.Chronic insulin dysregulation is challenging to manage with pharmaceuticals in horses. Pioglitazone improves insulin sensitivity in humans, and the pharmacokinetics of pioglitazone have been evaluated in horses. The objectives of this study were to assess the pharmacodynamic effects of oral pioglitazone on morphometric parameters, hepatic enzyme activity and function, adipokines, and enteroinsular response to oral sugar. A prospective pilot study was performed using fifteen adult equids (8 ponies, 7 horses) to evaluate the effects of short-term pioglitazone administration (2Â mg/kg PO q 24 hou...
Nikvand AA, Jalali SM, Ghadrdan Mashhadi A, Razi Jalali M, Hassanpour Amirabadi S.The efficacy of clinical examinations, and hematologic, hemostatic, and serum biochemical assessments to determine appropriate early medical or surgical therapy in Arabian horses with colic have not been well-described. Objective: We aimed to evaluate clinical and hematologic findings, coagulation-fibrinolytic parameters, and organ dysfunction markers in association with survival in horses with colic. Methods: Seventeen Arabian horses with colic and ten healthy horses were enrolled. After clinical examinations, including heart rates (HRs), capillary refill times (CRTs), abdominal sounds, recta...
Schedlbauer C, Blaue D, Gericke M, Blüher M, Starzonek J, Gittel C, Brehm W, Vervuert I.Non-alcoholic fatty liver disease is known as determining part of human obesity. The impact of body weight (BW) gain on liver metabolism has not been extensively investigated yet. Objective: To investigate hepatic alterations caused by increasing BW in ponies and horses. Methods: A total of 19 non-obese equines (10 Shetland ponies, geldings; nine Warmblood horses, geldings). Methods: Animals received 200% of their metabolizable maintenance energy requirements for 2 years. Serum alkaline phosphatase, glutamate dehydrogenase (GLDH), aspartate aminotransferase (AST), and gamma-glutamyl transferas...
MolÃn J, AsÃn J, Vitoria A, Sanz A, Gimeno M, Romero A, Sánchez J, Pinczowski P, Vázquez FJ, Rodellar C, Luján L.A 1-month-old Purebred Spanish Horse (PSH) foal presented with progressive hepatic failure culminating in death. Hepatic lesions were consistent with congenital hepatic fibrosis (CHF). Genetic studies in the PKHD1 gene in the affected foal revealed that it was heterozygous for the 2 previously described single-nucleotide polymorphisms (SNPs) linked to CHF in Swiss Franches-Montagnes (SFM) horses. In addition, 2 novel mutations were detected, the foal being homozygous for one of them and heterozygous for the other. Genetic studies in a healthy PSH population ( n = 35) showed a 3-fold higher gen...
Berlin S, Wallstabe S, Scheuch E, Oswald S, Hasan M, Wegner D, Grube M, Venner M, Ullrich A, Siegmund W.Standard treatment of foals with severe abscessing lung infection caused by Rhodococcus equi using rifampicin and a macrolide antibiotic can be compromised by extensive inhibition and/or induction of drug metabolising enzymes (e.g. CYP3A4) and transport proteins (e.g. P-glycoprotein), as has been shown for rifampicin and clarithromycin. The combination of rifampicin with the new, poorly metabolised gamithromycin, a long-acting analogue of azithromycin and tulathromycin with lower pharmacokinetic interaction potential, might be a suitable alternative. Objective: To evaluate the pharmacokinetic ...
Shibany KA, Tötemeyer S, Pratt SL, Paine SW.1. Scaling factor values for the in vitro-in vivo extrapolation of hepatic metabolic clearance for xenobiotics have not yet been determined in horses. Scaling factors were determined by comparing the total protein and or cytochrome (CYP) P450 content in microsomes and cryopreserved hepatocytes against the content in the liver. 2. Microsomal protein per gram of liver (MPPGL) and hepatocellularity number per gram of liver (HPGL) using CYP P450 content method ranged 41-73 mg/gram of liver (mean= 57 mg/gram of liver, n = 39) and 146-320 × 10 cells/g of liver (mean = 227× 10 c...
Tóth B, Auth A, Rompos L, Bakos Z.Gastrointestinal and other systemic diseases of Equidae are often characterised by partial or complete inappetence. The catabolic processes may lead to lipid mobilisation and other metabolic disturbances. Evidence from earlier studies has revealed that during feed deprivation/inappetence, the conjugation of bilirubin is reduced causing a substantial rise of the total bilirubin and its unconjugated fraction. Objective: We hypothesised that during feed deprivation, the serum concentration of free fatty acids (FFA), triglycerides (TG), blood urea nitrogen (BUN), total bilirubin (tBIL), total bile...
Shibany KA, Tötemeyer S, Pratt SL, Paine SW.Despite reports of the successful isolation of primary equine hepatocytes, there are no published data regarding the successful cryopreservation of these isolated cells. In this study, a detailed description of the procedures for isolation, cryopreservation, and recovery of equine hepatocytes are presented. Furthermore, the intrinsic clearance (Cl) and production of metabolites for three drugs were compared between freshly isolated and recovered cryopreserved hepatocytes. Primary equine hepatocytes were isolated using a two-step collagenase perfusion method, with an average cell yield of 2.47Â...
Mittelman NS, Engiles JB, Murphy L, Vudathala D, Johnson AL.An 8-year-old Holsteiner gelding was presented for evaluation of anorexia, obtundation, icterus, and mild colic signs of 48 hours duration. History, physical examination, and initial diagnostics were suggestive of hepatic disease and encephalopathy. Microcystin toxicosis was suspected based on historical administration of a cyanobacteria supplement, associated serum biochemistry abnormalities, and characteristic histopathological changes. Microcystin contamination was confirmed in both supplement containers fed to the horse. Fulminant hepatic failure and encephalopathy progressed resulting in ...
Greeve J, Altkemper I, Dieterich JH, Greten H, Windler E.Two different isoproteins are encoded by the apolipoprotein (apo) B gene, apoB-48 and apoB-100. ApoB-48, core component of intestinally derived chylomicrons, has an accelerated plasma turnover as compared with the full-length protein apoB-100. A posttranscriptional modification of the apoB mRNA by conversion of cytidine into uridine at nucleotide position 6666 changes the genomically encoded glutamine codon CAA at amino acid residue 2153 into a translational stop codon UAA. This mRNA editing explains the formation of the truncated isoform apoB-48. In the present investigation editing of apoB m...
Epe C, Coati N, Schnieder T.The results of coproscopical examinations in horses, ruminants, pigs, dogs, cats, hedgehogs and rabbits between 1998 and 2002 are presented. In 4399 samples from horses 37.4% stages of strongylids, 1.4% anoplocephalids, 1.3% Strongyloides westeri, 0.9% Parascaris equorum, 0.04% Oxyuris equi, 0.04% Eimeria sp. and 0.04% Fasciola hepatica were found. In 998 samples of cattle 22.1% stages of strongylids, 11.2% of Eimeria spp., 3.5% of cryptosporidium, 2.9% of Moniezia spp., 1.3% of Trichuris spp., 0.7% of Dictyocaulus sp., 0.6% of Fasciola hepatica, 0.6% of Strongyloides sp., 0.5% of Nematodirus ...
Porter RK, Brand MD.Resting O2 consumption of hepatocytes isolated from mammals ranging in mass from 20-g mice to 200-kg horses decreases with increasing body mass. The substrate oxidation system increases in activity with increasing body mass and mitochondrial proton leak and phosphorylation system decrease in activity, resulting in a higher mitochondrial membrane potential in hepatocytes from larger mammals. The absolute rates of O2 consumption due to nonmitochondrial processes, substrate oxidation, mitochondrial proton leak, and the phosphorylation system decrease with increasing body mass. These decreases are...
Court MH, Von Moltke LL, Shader RI, Greenblatt DJ.The 6-hydroxylation of chlorzoxazone (CLZ) is currently being used in both in vivo and in vitro studies to quantify cytochrome P450 2E1 (CYP2E1) activity in humans. Comparatively little is known with regard to the biotransformation of this drug in other species. The NADPH-dependent biotransformation of CLZ was therefore studied using hepatic microsomes derived from humans and ten other mammalian species. In all species, 6-hydroxychlorzoxazone (6OH-CLZ) was the only metabolic product that could be identified by HPLC with ultraviolet detection. Enzyme kinetic analysis was used to characterize th...
Oelrichs PB, Calanasan CA, MacLeod JK, Seawright AA, Ng JC.Regular ingestion of Eupatorium adenophorum [Ageratina adenophora (Spreng.)] or Crofton weed causes chronic pulmonary disease in horses mainly in Australia, New Zealand, and the Himalayas. The disease is characterized by pulmonary interstitial fibrosis, emphysema, alveolar epithelisation and reduced tolerance to exercise. Horses apparently are the only animals affected and there are numerous reports of farms losing all their horses. The disorder was produced experimentally in horse feeding trials, and it was shown that characteristic lesions occurred in the lungs. In studies with laboratory an...
Berg LC, Thomsen PD, Andersen PH, Jensen HE, Jacobsen S.mRNA expression of the acute phase protein serum amyloid A (SAA) in histologically normal tissues derived from horses (n=13) and cattle (n=4) was investigated by quantitative reverse-transcriptase real-time polymerase-chain reaction. As expected, high constitutive SAA mRNA expression was demonstrated in hepatic tissue in both species. In horses, moderate (>1% of the hepatic expression) SAA mRNA expression was detected in the lung, mammary gland, pancreas, synovial membrane, thymus, thyroid gland and uterus. Other equine tissues and organs sampled included adipose tissue, adrenal gland, aort...
Tedesco DEA, Guerrini A.Milk thistle, Silybum marianum, is a medicinal plant grown for its bioactive compounds with well-documented antioxidant and hepatoprotective properties. Milk thistle has a well-established pharmacological reputation for treatments of human liver disease, but it is also used in animals. This review summarizes the experimental evidence of milk thistle's effects on animals when administered as silymarin extract (feed additive) or a feed ingredient, if administered as seed or expeller/cake with the seed residue still containing the bioactive components. The use as a feed additive or feed ingredien...
Divers TJ, Cummings JE, de Lahunta A, Hintz HF, Mohammed HO.To determine whether equine motor neuron disease (EMND) could be induced in adult horses fed a diet low in vitamin E and high in copper and iron. Methods: 59 healthy adult horses. Methods: Horses in the experimental group (n = 8) were confined to a dirt lot and fed a concentrate low in vitamin E and high in iron and copper in addition to free-choice grass hay that had been stored for 1 year. Control horses (n = 51) were fed a concentrate containing National Research Council-recommended amounts of copper, iron, and vitamin E. The hay fed to control horses was the same as that fed to experimenta...
Palmer DG, Lyon J, Palmer MA, Forshaw D.To determine the specificity and sensitivity of a commercial copro-antigen ELISA for the detection of Fasciola hepatica infection in cattle and sheep and to assess the suitability of the test for use in horses. Methods: Testing was done on more than 100 negative faecal samples from each of sheep, cattle and horses and on at least 40 positive faecal samples from each species. Positive samples were selected based on a positive sedimentation test for liver fluke eggs. Faecal samples of animals from Western Australia, which is free of liver fluke infection, served as negative controls. Specificity...
Tobin T, Chay S, Kamerling S, Woods WE, Weckman TJ, Blake JW, Lees P.Phenylbutazone is an acidic, lipophilic, non-steroidal anti-inflammatory drug (NSAID). It is extensively metabolized in the horse. The metabolites so far identified, oxyphenbutazone, gamma-hydroxyoxyphenbutazone, account for some 25-30% of administered dose over 24 h. The plasma half-life of phenylbutazone and termination of its pharmacological action are determined primarily by its rate of hepatic metabolism. Phenylbutazone acts by inhibiting the cyclooxygenase enzyme system, which is responsible for synthesis of prostanoids such as PGE2. It appears to act on prostaglandin-H synthase and pros...
Mendel VE, Witt MR, Gitchell BS, Gribble DN, Rogers QR, Segall HJ, Knight HD.Nine adult horses were fed alfalfa hay cubes containing approximately 10% Senecio vulgaris until all horses had consumed approximately the same amount of toxic components of S vulgaris, pyrrolizidine alkaloids (PA). The amount of PA consumed was determined by the amount that induced clinical signs of PA toxicosis in 3 horses. The 6 other horses were given similar amounts per kilogram of body weight. An initial decrease of feed intake was observed when horses' diets were changed from alfalfa cubes to alfalfa/Senecio cubes, and feed intake was decreased further over 89 to 98 days. From 50 to 159...
McCashin FB, Gabel AA.Xylazine administered intramuscularly (IM) to horses at the dose level of 2 mg/kg was an effective sedative and preanesthetic for thiamylal sodium narcosis or thiamylal sodium and halothane anesthesia. Evaluation of response of cardiovascular, respiratory, and hepatic function did not indicate serious untoward effects, although cardiac and respiratory rate decreased, calculated vigor of left ventricular contraction decreased, calculated peripheral vascular resistance increased, and transient innocuous cardiac arrhythmias occurred. Effects of the anesthetics used on respiratory function (blood ...
Stegelmeier BL, Gardner DR, James LF, Molyneux RJ.Houndstongue (Cynoglossum officinale), a noxious weed that contains pyrrolizidine alkaloids (PAs), infests pastures and fields in the western United States and Europe. The purpose of this study was to develop techniques to better diagnose PA poisoning and describe the progression of gross and microscopic lesions caused by houndstongue intoxication. Six horses were gavaged daily with a suspension of houndstongue containing 5 or 15 mg/kg total PA for 14 days. Two horses were treated similarly with ground alfalfa as controls. Liver biopsy samples and serum biochemical and hematologic values were ...
Letendre LT, Tessman RK, McClure SR, Kvaternick VJ, Fischer JB, Hanson PD.To determine pharmacokinetic parameters and variables, firocoxib concentrations in urine and plasma, urine-to-plasma ratios, and the urine depletion profile of firocoxib and to evaluate whether the pharmacokinetic behavior of firocoxib was governed by linear processes after multiple doses of firocoxib were administered IV and orally. Methods: 6 healthy female horses (5 Paint horses and 1 Quarter Horse) in experiment 1 and 12 healthy male and female horses in experiment 2. Methods: In experiment 1, 6 horses were orally administered firocoxib paste once daily for 12 consecutive days, and plasma ...
Step DL, Blue JT, Dill SG.Acute, severe hemolytic anemia occurred in a horse being treated for tetanus with intravenous penicillin and tetanus antitoxin. During treatment, the horse developed a positive direct antiglobulin test and a high titer (maximum 1:1024) of IgG anti-penicillin antibody. The horse recovered from the tetanus and penicillin induced hemolytic anemia, but later developed acute hepatic failure, probably resulting from the administration of equine origin tetanus antitoxin.
Ross PF, Ledet AE, Owens DL, Rice LG, Nelson HA, Osweiler GD, Wilson TM.A study to evaluate the effects of dietary fumonisin B1 was conducted using 6 ponies (4 test and 2 control). A ration naturally contaminated with fumonisin B1 was fed in 3 phases: 1) 44 ppm fumonisin B1, 2) less than 1 ppm fumonisin B1, and 3) 88 ppm fumonisin B1. All ponies were monitored daily, weighed weekly, and limit fed at a rate of 0.8% body weight plus hay. Feed intake was measured daily, and a serum chemistry panel was completed once or twice weekly. Four to 7 days after initiation of the trial (Phase 1), all 4 test ponies had decreased feed consumption, and selected serum chemistry p...
Findlay GM, Maccallum FO.(1) Among 3,100 persons immunized against yellow fever with virus and immune serum over a period of five years, 89 cases of jaundice have been traced.(2) The symptoms are those of a hepatitis and closely resemble those produced by common infective hepatic jaundice, cases of which have frequently been noted as occurring in the same areas.(3) The average period between the time of inoculation and the development of hepatitis is between two and three months.(4) Attention is directed to the occurrence of hepatitis in horses, usually two to three months after immunization against the viruses of hor...
Vesonder R, Haliburton J, Stubblefield R, Gilmore W, Peterson S.Corn from an Arkansas farm, where three horses died and others became sick, was investigated for causative principles. Necropsy of the three horses revealed what appeared to be severe hepatic necrosis. Histopathological examination indicated a pattern of hepatic lesions that was suggestive of aflatoxin contamination of the feed. Mycological examination of the corn by dilution plating revealed 95% of the colonies as Aspergillus flavus. Chemical analysis of the corn for mycotoxins was positive for aflatoxin B1, B2, and M1 at concentrations of 114, 10, and 6 micrograms/Kg, respectively. Cyclopiaz...
Powis G, Snow DH.There are now several examples showing that experimentally induced changes in hepatic blood flow can have a marked effect upon the elimination of certain high clearance drugs. Changes in hepatic blood flow produced by exercise might therefore be expected to influence the clearance of these drugs. There was an increase of up to 100%, compound to control values, in the plasma levels of propranolol in horses given either d- or dl-propranolol, 0.2 mg/kg b.wt., and then subjected to sustained exercise for 30 minutes. There was, however, no similar increase with exercise in the plasma levels of anti...
Hasan M, Siegmund W, Oswald S.Cytochrome P450 3A (CYP) enzymes are involved in the elimination of many drugs and are known to be regulated by several environmental factors. Thus, it was the aim of this study to develop and validate an analytical method allowing estimation of the hepatic CYP3A enzyme activity using the 4-hydroxycholesterol to cholesterol ratio as an endogenous biomarker in serum. Both compounds were isolated from the biological matrix by liquid-liquid extraction using n-hexane after saponification with ethanolic sodium methoxide solution (2M) to cleave the steroids from their esterified forms without any ki...
McCornico RS, Duckett WM, Wood PA.Persistent hyperammonemia was diagnosed in 2 Morgan fillies with clinical signs that developed early in the postweaning period. Diagnostic evaluation, including routine serum chemistries, CBC, liver biopsy, hepatic ultrasonography, liver function test, and necropsy findings did not support a toxic, developmental, or infectious cause. Abnormal serum amino acid and urine orotic acid concentrations suggest that the foals may have had an inherited disorders described in humans as hyperornithinemia, hyperammonemia, and homocitrullinuria (HHH) syndrome. The disorder is thought to be caused by a defe...
Drögemüller M, Jagannathan V, Welle MM, Graubner C, Straub R, Gerber V, Burger D, Signer-Hasler H, Poncet PA, Klopfenstein S, von Niederhäusern R....Congenital hepatic fibrosis has been described as a lethal disease with monogenic autosomal recessive inheritance in the Swiss Franches-Montagnes horse breed. We performed a genome-wide association study with 5 cases and 12 controls and detected an association on chromosome 20. Subsequent homozygosity mapping defined a critical interval of 952 kb harboring 10 annotated genes and loci including the polycystic kidney and hepatic disease 1 (autosomal recessive) gene (PKHD1). PKHD1 represents an excellent functional candidate as variants in this gene were identified in human patients with autosoma...
Watson TD, Burns L, Packard CJ, Shepherd J.The incidence of hyperlipaemia in ponies is highest in mares in late gestation and then early in lactation. Plasma lipid and lipoprotein concentrations were measured to establish the metabolic basis for this and the lipoprotein composition of six healthy Shetland ponies was analysed before pregnancy, in the last six weeks of gestation and one month after foaling. In the pregnant ponies, the concentrations of cholesterol and triglyceride were significantly increased (both P < 0.05) because of increased concentrations of high density lipoproteins (HDL) and very low density lipoproteins (VLDL)...
Pearson EG, Andreasen CB.To evaluate the potential of excess dietary iron to cause hepatic lesions similar to those described in horses with suspected iron toxicosis or hemochromatosis. Methods: Prospective study. Methods: 6 adult male ponies. Methods: 4 ponies received 50 mg of iron/kg (22.7 mg/lb) of body weight each day by oral administration of ferrous sulfate, which contained 20% elemental iron; 2 ponies received only the carrier (applesauce). Complete blood counts, serum biochemical analyses, and hepatic tissue biopsies were performed, and serum iron concentrations were measured. Blood and tissue samples were ob...
Brownie CF, Cullen J.An isolate of Fusarium moniliforme (M-1225 Cairo #1) was cultured on autoclaved corn and fed daily to 5 ponies at a rate of 2.5 g corn/kg body wt. One pony developed clinical signs of toxicity after 28 days and was sacrificed. The remaining 4 ponies developed no clinical sign of toxicity even after extended exposure. Hematology, serum chemistry, cerebrospinal fluid (CSF), and liver and brain pathology were evaluated as possible diagnostic and prognostic indicators. Hematology was not informative. Aspartate aminotransferase and gamma-glutamyltranspeptidase activities were elevated only in the c...
Flaminio MJ, LaCombe V, Kohn CW, Antczak DF.A 12-year-old Quarter Horse mare that was nonresponsive to medical treatment was evaluated for chronic respiratory disease and hepatobiliary disease. Serum immunoglobulin concentrations were measured by use of radial immunodiffusion that revealed trace to nondetectable concentrations of IgG, IgG(T), IgM, and IgA. Use of serum protein electrophoresis confirmed agammaglobulinemia by the absence of the expected peak in the gamma region. In addition, vaccination with tetanus toxoid did not result in specific immunoglobulin production. Flow cytometric analysis of blood lymphocyte subpopulations rev...
Smith JE, Moore K, Cipriano JE, Morris PG.Occasionally, horses are given large amounts of iron to improve performance. Although iron deficiency could limit erythrocyte production and other functions related to nonhematological tissues, it probably only occurs in blood loss. We have developed an enzyme immunoassay for ferritin in equine sera and evaluated its relationship to iron stored in liver and spleen. Serum ferritin correlated significantly (P less than 0.0001) with the concentration of nonheme iron in the liver and spleen. It increased following iron therapy and decreased after phlebotomy. We conclude that serum ferritin provide...
Pennington MR, Curtis TM, Divers TJ, Wagner B, Ness SL, Tennant BC, Van de Walle GR.Adult equine hepatocytes have proven challenging to culture long term in vitro as they rapidly lose their morphology and functionality, thus limiting studies on liver function and response to disease. In this study, we describe for the first time the differentiation of equine mesenchymal stromal cells (MSC) from a variety of sources into functional hepatocyte-like cells (HLC). First, we differentiated equine umbilical cord blood (UCB)-derived MSC into HLC and found that these cells exhibited a distinct polygonal morphology, stored glycogen as visualized by periodic acid Schiff's reagent staini...
