Metabolic health in horses refers to the physiological processes that manage energy production, utilization, and storage in equine bodies. These processes are critical for maintaining overall health, performance, and well-being. Metabolic health encompasses various aspects, including glucose metabolism, insulin sensitivity, and lipid regulation. Conditions such as Equine Metabolic Syndrome (EMS) and insulin dysregulation are common metabolic disorders that affect horses, impacting their ability to process and store energy efficiently. This topic compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, diagnostic approaches, and management strategies related to metabolic health in horses.
Wright AL, Earley ET, Austin C, Arora M.Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) is a common, painful and poorly understood disease. Enamel, dentin and cementum accumulate both essential and toxic trace elements during mineralization. Characterization of the spatial accumulation pattern of trace elements may provide insight into the role that toxic elements play and inform biological processes affecting these hard dental tissues for future research. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to map the distribution of multiple trace elements and heavy metals across equin...
Kellon EM, Gustafson KM.Sodium-Glucose CoTransporter-2 (SGLT2) inhibitors, the -flozin group of drugs, which block glucose reuptake in the renal proximal tubule, are being increasingly used off-label to treat horses with refractory hyperinsulinemia. After 2 years of use by animals in our group, a horse on canagliflozin was incidentally noted to be hyperlipemic. We have been following a cohort of equines (n = 20) treated with SGLT2 inhibitors due to refractory hyperinsulinemia. The animals are owned by members of the Equine Cushing's and Insulin Resistance Group and treated by their attending veterinarians. The index ...
Bourebaba L, Serwotka-Suszczak A, Pielok A, Sikora M, Mularczyk M, Marycz K.Equine metabolic syndrome (EMS) is a multifactorial pathology gathering insulin resistance, low-grade inflammation and past or chronic laminitis. Among the several molecular mechanisms underlying EMS pathogenesis, increased negative insulin signalling regulation mediated by protein tyrosine phosphatase 1 B (PTP1B) has emerged as a critical axis in the development of liver insulin resistance and general metabolic distress associated to increased ER stress, inflammation and disrupted autophagy. Thus, the use of PTP1B selective inhibitors such as MSI-1436 might be considered as a golden therapeut...
de Laat MA, Fitzgerald DM.Equine insulin dysregulation (ID) comprises amplified insulin responses to oral carbohydrates or insulin resistance, or both, which leads to sustained or periodic hyperinsulinaemia. Hyperinsulinaemia is important in horses because of its clear association with laminitis risk, and the gravity of this common sequela justifies the need for a better understanding of insulin and glucose homoeostasis in this species. Post-prandial hyperinsulinaemia is the more commonly identified component of ID and is diagnosed using tests that include an assessment of the gastrointestinal tract (GIT). There are se...
Carver C, Bruemmer J, Coleman S, Landolt G, Hess T.Laminitis associated with equine metabolic syndrome causes significant economic losses in the equine industry. Diets high in non-structural carbohydrates (NSC) have been linked to insulin resistance and laminitis in horses. Nutrigenomic studies analyzing the interaction of diets high in NSCs and gene expression regulating endogenous microRNAs (miRNA) are rare. This study's objectives were to determine whether miRNAs from dietary corn can be detected in equine serum and muscle and its impacts on endogenous miRNA. Twelve mares were blocked by age, body condition score, and weight and assigned to...
Pratt-Phillips S, Munjizun A.There is ample research describing the increased risk of health concerns associated with equine obesity, including insulin dysregulation and laminitis. For athletes, the negative effect of weight carriage is well documented in racing thoroughbreds (i.e., handicapping with weight) and rider weight has been shown to impact the workload of ridden horses and to some degree their gait and movement. In many groups of competitive and athletic horses and ponies, obesity is still relatively common. Therefore, these animals not only are at risk of metabolic disease, but also must perform at a higher wor...
MacNicol JL, Renwick S, Ganobis CM, Allen-Vercoe E, Weese JS, Pearson W.The microbes that reside within the equine hindgut create a complex and dynamic ecosystem. The equine hindgut microbiota is intimately associated with health and, as such, represents an area which can be beneficially modified. Synbiotics, supplements that combine probiotic micro-organisms with prebiotic ingredients, are a potential means of influencing the hindgut microbiota to promote health and prevent disease. The objective of the current study was to evaluate the influence of an equine probiotic/prebiotic supplement on characteristics of the microbiota and metabolite production in vitro. E...
Ribeiro RM, Ribeiro DDSF, Cota LO, Carvalho AM, Gobesso AAO, Faleiros RR.This study aimed to compare the use of enzymatic colorimetry and Friedewald's formula for the determination of LDL in horses. A total of 260 samples were used. Direct analysis was performed to determine low-density lipoprotein (LDL), high-density lipoprotein (HDL) cholesterol, triglycerides (TG), and total cholesterol (TC). The LDL level was calculated using the Friedewald equation (LDL= TC-HDL-TG/5). The correlations between the direct LDL analysis and the LDL calculated using the Friedewald formula were determined by Pearson's tests, and the coefficient of determination was also obtained by ...
Marycz K, Bourebaba N, Serwotka-Suszczak A, Mularczyk M, Galuppo L, Bourebaba L.Equine metabolic syndrome (EMS) is recognized as one of the leading cause of health threatening in veterinary medicine worldwide. Recently, PTP1B inhibition has been proposed as an interesting strategy for liver insulin resistance reversion in both equines and humans, however as being a multifactorial disease, proper management of EMS horses further necessities additional interventional approaches aiming at repairing and restoring liver functions. In this study, we hypothesized that in vitro induction of Eq_ASCs hepatogenic differentiation will generate a specialized liver progenitor-like cell...
Turner S, Knych HK, Adams AA.Cannabidiol (CBD) has potential to reduce pain and inflammation in humans leading to the interest of use in equine. The purpose of this study was to determine the effects of CBD on immune function by measuring inflammatory cytokines and antibody responses to vaccination, as well as other health parameters in senior horses. Horses were orally-dosed with CBD (2 mg/kg: 13 horses) or control (soy oil: 14 horses) daily for 90 days, from July 2021 to November 2021. Peripheral blood samples were collected on days 0, 30, 60, and 90 before administering treatments. On day 90 all horses were kept on tr...
Zapf AM, Fey K, Büttner K, Gröf M, Staszyk C.Pituitary pars intermedia dysfunction (PPID) and dental disorders are of major concern in horses older than 15 years. Although PPID in geriatric horses and dental disorders in all age groups are well described, a connection between this endocrine disease and pathological changes in equine dental structures has not yet been investigated. In humans, periodontitis is considered to be a complication of systemic diseases like diabetes mellitus type 2, obesity and various conditions leading to an impaired immune response. In PPID, cross links to insulin and immune dysregulations are proven. The aim ...
Li FI, Spence RJ, de Laat MA, Harris PA, Sonntag J, Menzies-Gow NJ, Durham AE, Bailey SR, Sillence MN.High concentrations of adrenocorticotropic hormone (ACTH) are used as an indicator of pituitary pars intermedia dysfunction (PPID), but other factors that may influence ACTH need to be understood, if diagnostic reference ranges for ACTH are to be used with confidence. Insulin dysregulation (ID) could be one such factor, as insulin affects pituitary hormones in other species. Objective: To test the hypothesis that a relationship exists between high insulin and high ACTH in aged (>15-year-old) animals with no clinical signs of PPID. Methods: A cohort study. Methods: Thirteen horses and eleven p...
Warnken T, Schaub C, Delarocque J, Frers F, Feige K, Sonntag J, Reiche DB.Oral glycemic challenge (GC) tests are recommended for diagnosis of insulin dysregulation (ID). Various protocols are used, but all have limitations in terms of palatability, ease of use, variable composition, geographic availability, or some combination of these. Objective: To evaluate newly developed formulations with defined carbohydrate composition for use as oral GCs. Methods: Thirty-four horses and ponies in various metabolic states. Methods: Our objectives were carried out in 2 separate cross-over experiments. First, the palatability and acceptance of various GCs (2 syrups, 1 granulate)...
Manfredi JM, Jacob S, Norton E.Endocrine disorders are associated with joint pain and tendon injury in humans, but the effects in the horse are only starting to be understood. Similar patterns of clinical signs and injury appear to affect horses and humans for both orthopedic and endocrine disorders, supporting the use of a one-health approach to tackle these issues. In this Currents in One Health, we will discuss common equine endocrinopathies, current testing recommendations, dietary management, genetic predispositions, and endocrine disorders' effects on performance. Our aim is to use a one-health lens to describe curren...
Pratt-Phillips S, Munjizun A, Janicki K.Obesity is a critical problem in the equine industry, with ponies being at particularly high risk of developing obesity-related conditions such as metabolic syndrome and laminitis. The purpose of this study was to estimate the level of adiposity in an elite level of competitive show ponies, and to determine if adiposity was related to performance based on their model score (judged on conformation and appearance). Two researchers visually evaluated the body condition score (BCS) and cresty neck score (CNS) of 377 ponies at a national hunter competition. Thirty five percent of the ponies in the ...
de Laat MA, Warnken T, Delarocque J, Reiche DB, Grob AJ, Feige K, Carslake HB, Durham AE, Sillence MN, Thane KE, Frank N, Brojer J, Lindase S....A glycemic challenge test is used for the diagnosis of insulin dysregulation (ID) in horses and ponies. Different forms of the test exist where the administrative route and dose of glucose vary, which makes interpretation of results challenging. Objective: To evaluate the palatability of, and blood glucose and insulin responses to, carbohydrate pellets fed as an oral glucose test (OGT), and to establish the diagnostic threshold for ID when using the pellets. Methods: University and privately-owned horses and ponies (n = 157) comprised of 31 breeds and both sexes. Methods: Multicenter cohort ...
Manfredi JM, Jacob SI, Boger BL, Norton EM.Endocrinopathies affect multiple species in ever-increasing percentages of their populations, creating an opportunity to apply one-health approaches to determining creative preventative measures and therapies in athletes. Obesity and alterations in insulin and glucose dynamics are medical concerns that play a role in whole-body health and homeostasis in both horses and humans. The role and impact of endocrine disorders on the musculoskeletal, cardiovascular, and reproductive systems are of particular interest to the athlete. Elucidation of both physiologic and pathophysiologic mechanisms invol...
Prasinou P, De Amicis I, Fusaro I, Bucci R, Cavallini D, Parrillo S, Caputo M, Gramenzi A, Carluccio A.Fatty acid-based lipidomic analysis has been widely used to evaluate health status in human medicine as well as in the veterinary field. In equine species, there has been a developing interest in fertility and sperm quality. Fatty acids, being the principal components of the membranes, play an active role in the regulation of the metabolic activities, and their role on spermiogenesis seems to be of great importance for the resulting quality of the sperm and, thus, fertility. With the application of widely used lipidomic techniques, the aim of this study was to evaluate: (a) the fatty acid cont...
Macon EL, Harris P, Bailey S, Caldwell Barker A, Adams A.Identifying intake levels of nonstructural carbohydrates (NSCs) that limit the postprandial insulinaemic response in the insulin dysregulated (ID) horse may help reduce hyperinsulinaemia-associated laminitis (HAL) risk. Objective: To determine if ID horses have thresholds for pure sources of starch and sugar, above which there is an augmented insulin response. Methods: Randomised crossover experiment. Methods: Fourteen adult horses (6 ID and 8 noninsulin dysregulated, NID; matched for bodyweight) were randomly fed eight dietary treatments. Dietary treatments were formulated using a base of low...
Stoeckle SD, Timmermann D, Merle R, Gehlen H.Laminitic horses commonly suffer from an endocrine disease such as equine metabolic syndrome. Hyperinsulinemia is considered a key factor in the pathogenesis of laminitis. Since insulin also affects protein turnover in the body, the resting plasma amino acid concentrations of obese horses that were presented for a combined glucose insulin test (CGIT) were determined. In total, 25 obese horses and two lean horses with recurrent laminitis underwent a CGIT. Of these, five were not insulin dysregulated (obese), 14 were insulin dysregulated (ID), and eight were insulin-dysregulated and laminitic (I...
Berryhill EH, Urbina NS, Marton S, Vernau W, Alonso FH.The Wellness Ready Test (WRT) is a lateral flow, stall-side assay that measures equine insulin in whole blood and requires validation before recommending clinical use. We evaluated intra- and inter-assay precision and linearity and compared the WRT with a radioimmunoassay (RIA). Tested concentrations ranged from 695 pmol/L (100 μIU/mL). For 20 replicates at each insulin level, intra-assay CVs of the WRT for insulin were 13.3%, 12.9%, and 15.3% at low (139-278 pmol/L; 20-40 μIU/mL), intermediate (278-417 pmol/L; 40-60 μIU/mL), and high (>417 >60 μIU/mL) concentrations...
Bustamante CC, de Paula VB, Rabelo IP, Fernandes CC, Kishi LT, Canola PA, Lemos EGM, Valadão CAA.Starch overload in horses causes gastrointestinal and metabolic disorders that are associated with microbiota changes. Therefore, we identified the fecal microbiota and hypothesized that intracecal injection of alkaline solution (buffer; Mg(OH)2 + Al(OH)3) could stabilize these microbiota and clinical changes in horses submitted to corn starch overload. Ten crossbred horses (females and geldings) were allocated to group I (water−saline and starch−buffer treatments) and group II (water−buffer and starch−saline treatments). Clinical signs, gross analysis of the feces, and fecal microbiot...
Kinsella HM, Hostnik LD, Toribio RE.Most homeostatic systems in the equine neonate should be functional during the transition from intra- to extrauterine life to ensure survival during this critical period. Endocrine maturation in the equine fetus occurs at different stages, with a majority taking place a few days prior to parturition and continuing after birth. Cortisol and thyroid hormones are good examples of endocrine and tissue interdependency. Cortisol promotes skeletal, respiratory, cardiovascular, thyroid gland, adrenomedullary, and pancreatic differentiation. Thyroid hormones are essential for cardiovascular, respirator...
Daradics Z, Niculae M, Crecan CM, Lupșan AF, Rus MA, Andrei S, Ciobanu DM, Cătoi FA, Pop ID, Mircean MV, Cătoi C.Obesity is a common feature in horses suffering from metabolic syndrome. While adipokines involvement as biomarkers is better established in human pathology, little data are available on horses. This study aimed to investigate the possible association and relationship between selected metabolic parameters and morphological traits in equine metabolic syndrome. Adiposity was evaluated using body condition score (BCS) and cresty neck score (CNS). Plasma levels of total cholesterol, insulin, NEFA, and adipokines (omentin and chemerin) were determined using enzyme-linked immunosorbent assays. Spear...
Boldt E.Horses 15 years of age and older now account for a significant portion of the equine population. Integrative therapies can provide important diagnostic and treatment tools for managing and maintaining the health of geriatric horses. Aged horses are often afflicted with chronic disease processes that are difficult to effectively manage with conventional medicinal approaches, such as laminitis and osteoarthritis. Diagnostic and therapeutic approaches using integrative therapies, such as acupuncture and spinal manipulation, are presented in this article for managing aged horses with metabolic dis...
Jayathilake WMNK, Furr M, Risco C, Lacombe VA.Similar to human diabetes, equine metabolic syndrome (EMS) causes insulin dysregulation leading to debilitating sequela including laminitis. The pathophysiological mechanisms underlying EMS and laminitis are not well known. Therefore, using an insulin-resistant equine model, we hypothesized that insulin dysregulation induces an increased expression of inflammatory proteins in a tissue specific manner. Two groups of horses (n = -5/group) were categorized as insulin-resistant (IR) or insulin-sensitive (IS), using a frequently sampled intra-venous glucose tolerance test. Biopsies from skeletal ...
Sibthorpe PEM, Fitzgerald DM, Chen L, Sillence MN, de Laat MA.To determine the effect of a starch-rich treat, added to the daily diet of ponies for 10 days, on enteroinsular responses to meal consumption. 10 mixed-breed adult ponies owned by Queensland University of Technology were used in the study. Six ponies were metabolically healthy, and 4 were insulin dysregulated at the start of the study, according to the results of an in-feed oral glucose test. A bread-based treat was offered twice daily for 10 days, adding 0.36 ± 0.04 g/kg body weight (BW) carbohydrates to the daily diet. Before and after treatment, the intestinal capacity for simple carbohydr...
Ishii H, Shibuya M, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Sato F, Kuroda T, Yamada M, Leung GN.In drug metabolism studies in horses, non-targeted analysis by means of liquid chromatography coupled with high-resolution mass spectrometry with data-dependent acquisition (DDA) has recently become increasingly popular for rapid identification of potential biomarkers in post-administration biological samples. However, the most commonly encountered problem is the presence of highly abundant interfering components that co-elute with the target substances, especially if the concentrations of these substances are relatively low. In this study, we evaluated the possibility of expanding DDA coverag...
Main SC, Brown LP, Melvin KR, Campagna SR, Voy BH, Castro HF, Strickland LG, Hines MT, Jacobs RD, Gordon ME, Ivey JLZ.The large population of emaciated horses continues to be an issue troubling the equine industry. However, little is known regarding the collection of equine metabolites (metabolome) during a malnourished state and the changes that occur throughout nutritional rehabilitation. In this study, ten emaciated horses underwent a refeeding process, during which blood samples were collected for a blood chemistry panel and metabolomics analysis via ultrahigh performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Significant differences among blood chemistry analytes and metabo...
Dolan E, O'Connor H, McGoldrick A, O'Loughlin G, Lyons D, Warrington G.In this study, we describe diet and lifestyle practices of professional jockeys. Participants completed a 59-item nutrition, lifestyle, and health questionnaire (n = 21) and a 7-day estimated food diary (n = 18). Acute weight loss strategies included the use of saunas (86%), exercising to induce sweating (81%), and restricted energy intake (71%). Of the smokers (38%), 56% used smoking to control weight. Most (86%) jockeys reported attaining a 2-kg weight loss for racing (if required) 24-48 h before or on the designated race-day. Mean daily energy intake (1803 ± 564 kcal) was low and appeared ...
Carter RA, McCutcheon LJ, Valle E, Meilahn EN, Geor RJ.To determine effects of exercise training without dietary restriction on adiposity, basal hormone and lipid concentrations and glucose and insulin dynamics in overweight or obese, insulin-resistant horses. Methods: 12 overweight or obese (body condition score > or = 7), insulin-resistant (insulin sensitivity < or = 1.2 x 10(-4) L/min/mU) geldings. Methods: 4 horses remained sedentary, and 8 horses were exercised for 4 weeks at low intensity and 4 weeks at higher intensity, followed by 2 weeks of detraining. Prior to and after each training period, frequently sampled IV glucose tolerance ...
Tadros EM, Fowlie JG, Refsal KR, Marteniuk J, Schott HC.Hyperinsulinaemia is the suspected component of insulin dysregulation having the strongest association with laminitis and occurs variably in equids with pituitary pars intermedia dysfunction (PPID). Objective: We hypothesised that magnitude of hyperinsulinaemia correlates with laminitis severity in PPID-affected equids. Furthermore, we hypothesised that owners can be unaware of chronic endocrinopathic laminitis. Methods: Cross-sectional study. Methods: Serum insulin concentrations, owner-reported laminitis history and radiographic evidence of laminitis were determined in 38 client-owned horses...
O'Callaghan DJ, Hyde JM, Gentry GA, Randall CC.Infection of exponential-phase suspension cultures of mouse fibroblast cells (L-M) with equine abortion virus (EAV) resulted in inhibition of cell growth and marked alterations in host metabolic processes. The synthesis of deoxyribonucleic acid (DNA) and ribonucleic acid was inhibited within 4 hr after infection and was suppressed by more than 90% by the time of maximal virus replication (14 to 18 hr). The overall rate of protein synthesis, however, was similar in uninfected and virus-producing cells as determined by measurements of net protein and isotope incorporation. The time course of vir...
Skedros JG, Mason MW, Nelson MC, Bloebaum RD.Functionally induced strains provide epigenetic signaling for bone modeling and remodeling activities. Strain gauge documentation of the equine third metacarpal reveals a neutral axis passing through the craniolateral cortex, resulting in a narrow band of cortex loaded predominantly in tension, with the remainder of the cortex experiencing a wide range of compression strain magnitudes that are maximal in the caudomedial cortex. This predictable strain pattern provides a model for examining the hypothesis that strain mode, magnitude, and strain energy density are potential correlates of compact...
Katz LM, Bailey SR.With the increasing number of studies being published on the different experimental models used to induce and study acute laminitis, the pathophysiological events associated with these various models (i.e. starch overload, oligofructose overload, black walnut extract and hyperinsulinaemia) can be compared more realistically. Within this review, the mechanisms for metabolic vs. inflammatory laminitis are discussed, and the question of how pasture laminitis may fit into any of the proposed mechanisms is addressed.
Morgan RA, McGowan TW, McGowan CM.To determine the prevalence of hyperinsulinaemia in a population of ponies in Queensland, Australia, and identify associated factors. Methods: Breeders or traders of ponies within a 100 km radius of Gatton, Queensland, were recruited for study using an internet database. Clinical and management details were obtained, including body condition score, fat deposition and history or evidence of laminitis. Blood samples were analysed for serum insulin and triglyceride concentrations and plasma adrenocorticotrophic hormone (ACTH) and leptin concentrations following short-term removal from pasture and...
Marycz K, Kornicka K, Irwin-Houston JM, Weiss C.Endocrine disorders have become more and more frequently diagnosed in humans and animals. In horses, equine metabolic syndrome (EMS) is characterized by insulin resistance, hyperleptinemia, hyperinsulinemia, inflammation and usually by pathological obesity. Due to an increased inflammatory response in the adipose tissue, cytophysiological properties of adipose derived stem cells (ASC) have been impaired, which strongly limits their therapeutic potential. Excessive accumulation of reactive oxygen species, mitochondria deterioration and accelerated ageing of those cells affect their multipotency...
Argo CM, Curtis GC, Grove-White D, Dugdale AH, Barfoot CF, Harris PA.Evidence-based, weight loss management advice is required to address equine obesity. Changes in body mass (BM), body condition score (BCS), heart (HG) and belly circumference (BG), direct (ultrasonographic) and indirect (D(2)O dilution, bioelectrical impedance analysis [BIA]) measures of body fat as well as indices of insulin resistance (IR) were monitored in 12 overweight (BCS ≥ 7/9) horses and ponies of mixed breed and gender for 16 weeks. Animals were randomly assigned to two groups (Group 1, n=6, BCS 7.6/9 ± 0.6, 489 ± 184.6 kg; Group 2, n=6, BCS 8.1/9 ± 0.6, 479 ± 191.5 kg). Daily d...
Kuhl J, Winterhoff N, Wulf M, Schweigert FJ, Schwendenwein I, Bruckmaier RM, Aurich JE, Kutzer P, Aurich C.Many foals develop diarrhoea within the first two weeks of life which has been suggested to coincide with postpartum oestrus in their dams. To analyse the pathogenesis of this diarrhoea we have determined faecal bacteria in foals and their dams (n=30 each), and serum IGF-1 and γ-globulins for 6 weeks after birth. In addition, effects of β-carotene supplementation to mares (group 1: 1000 mg/day, n=15, group 2: control, n=15) on diarrhoea in foals were studied. Diarrhoea occurred in 92 and 79% of foals in groups 1 and 2, respectively, but was not correlated with oestrus in mares. Beta-carotene...
Carslake HB, Pinchbeck GL, McGowan CM.Many diagnostic tests for insulin dysregulation use reference intervals established with an insulin radioimmunoassay (RIA) that is no longer available. A chemiluminescent immunoassay (CLIA) is commonly used for the measurement of serum insulin concentration in clinical practice but requires further validation, especially at clinically relevant reference intervals. Objective: To evaluate the CLIA for measurement of equine insulin and compare it to the previously validated, but now unavailable RIA. Methods: Equine serum samples (n = 78) from clinical and experimental studies. Methods: In this ex...
Muñoz A, Riber C, Trigo P, Castejón-Riber C, Castejón FM.Limited information exists concerning the defence of homeostasis during endurance competitions and the relationship with performance. Objective: This research analysed renin (REN), angiotensin II (ANG), aldosterone (ALD) and vasopressin (AVP) in horses covering different distances, assesses differences between successful and eliminated horses and evaluates correlations between hydration status, renal function, electrolytes, REN, ANG, ALD and AVP. Methods: Packed cell volume (PCV), velocity and serum concentrations of REN, ANG, ALD, AVP, Na, K, Cl, Ca, Mg, P, creatine kinase, aspartate aminotra...
Boehm AK, Seth M, Mayr KG, Fortier LA.Many metabolic processes in chondrocytes thought to contribute to age-related changes in the extracellular matrix are influenced by known roles of Hsp90. Age-related decreases in the level of Hsp90 have been documented in numerous cell types and could contribute to cartilage degeneration. The aim of this study was to investigate the roles of age and Hsp90 in insulin-like growth factor 1 (IGF-1) and interleukin-1beta (IL-1beta) signaling in chondrocytes. Methods: Levels of Hsp90 messenger RNA (mRNA) and protein, with respect to age, were determined by quantitative real-time polymerase chain rea...
Wiedmeyer CE, Johnson PJ, Cohn LA, Meadows RL, Kerl ME, Tessman RK, Perlis J, DeClue AE.With the emergence of continuous glucose monitoring systems being used to provide a detailed glucose picture in humans, a commercially available system (CGMS(R), Medtronic Minimed, Northridge, CA) was examined for use in veterinary species. Methods: Adult, clinically normal horses (n = 7), cats (n = 3), dogs (n = 4), and cows (n = 5) were studied. Cats (n = 4), dogs (n = 5), and one horse with diabetes were included in the study. Several of the normal horses, including the horse with diabetes, and one cow were subjected to an intravenous glucose tolerance test. The CGMS was attached to each an...
Boemer F, Detilleux J, Cello C, Amory H, Marcillaud-Pitel C, Richard E, van Galen G, van Loon G, Lefère L, Votion DM.Equine atypical myopathy (AM) is caused by hypoglycin A intoxication and is characterized by a high fatality rate. Predictive estimation of survival in AM horses is necessary to prevent unnecessary suffering of animals that are unlikely to survive and to focus supportive therapy on horses with a possible favourable prognosis of survival. We hypothesized that outcome may be predicted early in the course of disease based on the assumption that the acylcarnitine profile reflects the derangement of muscle energetics. We developed a statistical model to prognosticate the risk of death of diseased a...
Jacob SI, Geor RJ, Weber PSD, Harris PA, McCue ME.Glucose and insulin dynamics may be different in adult and aged horses. Objective: To determine the effects of age and dietary carbohydrates on glucose and insulin dynamics in healthy horses. Methods: Balanced Latin square with four isocaloric diets: CONTROL (hay plus restricted-starch-and-sugar fortified pellets), STARCH (control plus kibbled corn), FIBER (control plus unmolassed sugar beet pulp/soybean hull pellets) and SUGAR (control plus dextrose powder). Methods: A total of 16 healthy Thoroughbreds and Standardbreds divided into two age groups: ADULT (8.8 ± 2.9 years; n = 8) and AGE...
Johnson PJ, Wiedmeyer CE, Messer NT, Ganjam VK.There is growing recognition that obesity is common and represents a significant detriment to the health of companion animals in a manner similar to that by which it is affecting the human population. As is the case for other species, obesity appears to promote insulin resistance in horses and it is through this pathophysiological process that many of the adverse medical consequences of obesity are being characterized. Equine medical conditions that have been described in the context of obesity and insulin resistance differ from those in humans. Chronic human conditions that have been attribut...
Martin RB, Lau ST, Mathews PV, Gibson VA, Stover SM.We studied birefringence as an indicator of collagen fiber orientation in the diaphysis of the equine third metacarpal bone. We had previously shown that tissue from the lateral cortex of this bone is stronger monotonically, but less fatigue resistant, than tissue from the medial and dorsal regions. To learn whether collagen fiber orientation might play a role in this regional specialization, we tested three hypotheses using the same specimens: (1) collagen fiber orientation is regionally dependent; (2) remodeling changes collagen fiber orientation; (3) longitudinal collagen fibers correlate p...
Gim JA, Hong CP, Kim DS, Moon JW, Choi Y, Eo J, Kwon YJ, Lee JR, Jung YD, Bae JH, Choi BH, Ko J, Song S, Ahn K, Ha HS, Yang YM, Lee HK, Park KD....Athletic performance is an important criteria used for the selection of superior horses. However, little is known about exercise-related epigenetic processes in the horse. DNA methylation is a key mechanism for regulating gene expression in response to environmental changes. We carried out comparative genomic analysis of genome-wide DNA methylation profiles in the blood samples of two different thoroughbred horses before and after exercise by methylated-DNA immunoprecipitation sequencing (MeDIP-Seq). Differentially methylated regions (DMRs) in the pre-and post-exercise blood samples of superio...
Klein DJ, McKeever KH, Mirek ET, Anthony TG.The athletic horse, despite being over 50% muscle mass, remains understudied with regard to the effects of exercise and training on skeletal muscle metabolism. To begin to address this knowledge gap, we employed an untargeted metabolomics approach to characterize the exercise-induced and fitness-related changes in the skeletal muscle of eight unconditioned Standardbred horses (four male, four female) before and after a 12-week training period. Before training, unconditioned horses showed a high degree of individual variation in the skeletal muscle metabolome, resulting in very few differences ...
de Laat MA, Sillence MN.Insulin dysregulation can be difficult to diagnose from basal insulin and glucose concentrations, so a field-based oral glucose test (OGT) is preferred. However, the repeatability of this test has not been reported. Objective: To determine the repeatability of an in-feed OGT in ponies and examine some factors affecting the palatability of the test meal. Methods: A repeated measures, longitudinal study. Methods: An in-feed OGT was performed at 08.00 h on 3 consecutive occasions under controlled conditions in 8 mixed breed ponies. d-glucose (0.75 g/kg bwt) was dissolved in water and combined wit...
Zak A, Siwinska N, Elzinga S, Barker VD, Stefaniak T, Schanbacher BJ, Place NJ, Niedzwiedz A, Adams AA.Obesity and metabolic disorders are associated with systemic low-grade chronic inflammation, both in humans and animals. The aim of the study is to assess the effects of obesity and hyperinsulinemia on individual components of the acute-phase reaction in equine metabolic syndrome (EMS) horses. Eight mixed-breed EMS and six control, age-matched horses of both sexes were included in the study. Animals were classified as EMS or control based on the assessment of BCS, cresty neck score, and basal insulin >50 μU/mL and/or insulin responses to the oral sugar test (OST) >60 μU/mL. Peripheral ...
Coleman MC, Whitfield-Cargile CM, Madrigal RG, Cohen ND.Metabolic diseases such as obesity and type 2 diabetes in humans have been linked to alterations in the gastrointestinal microbiota and metabolome. Knowledge of these associations has improved our understanding of the pathophysiology of these diseases and guided development of diagnostic biomarkers and therapeutic interventions. The cellular and molecular pathophysiology of equine metabolic syndrome (EMS) and obesity in horses, however, remain ill-defined. Thus, the objectives of this study were to characterize the fecal microbiome, fecal metabolome, and circulating lipidome in obese and non-o...
Wylie CE, Collins SN, Verheyen KL, Newton JR.Laminitis is a highly debilitating disease of the foot known to have a complex and multifactorial aetiology of metabolic, inflammatory, traumatic or vascular origin. The disease has major welfare implications due to unrelenting pain associated with degenerative changes, which often necessitate euthanasia on welfare grounds. Despite this, there have been few high-quality studies investigating risk factors for equine laminitis, and only a limited number of risk factors have been previously investigated. The aim of this study was to conduct a case-control study of risk factors for active episodes...
Schott HC.PPID in older equids has become a major health concern of horse owners. In response, equine practitioners have made greater efforts at understanding, diagnosing, and treating this disorder. Although PPID is recognized to be a different form of pituitary-dependent hyperadrenocorticism than is seen in canine or human patients, relatively little is known about the pathophysiology and natural progression of the disease. At present, the diagnosis is best supported by manifestation of characteristic clinical signs and endocrinologic test results, preferably a supportive DST result. Treatment must fo...
Murphy BA, Wagner AL, McGlynn OF, Kharazyan F, Browne JA, Elliott JA.Circadian rhythms are endogenously generated 24-h oscillations that coordinate numerous aspects of mammalian physiology, metabolism and behaviour. The existence of a molecular circadian clock in equine skeletal muscle has previously been demonstrated. This study investigates how the circadian 24-h expression of exercise-relevant genes in skeletal muscle is influenced by a regular exercise regime. Mid-gluteal, percutaneous muscle biopsies were obtained over a 24-h period from six Thoroughbred mares before and after an 8-week exercise programme. Real-time qPCR assays were used to assess the expr...
Bryan K, McGivney BA, Farries G, McGettigan PA, McGivney CL, Gough KF, MacHugh DE, Katz LM, Hill EW.A single bout of exercise induces changes in gene expression in skeletal muscle. Regular exercise results in an adaptive response involving changes in muscle architecture and biochemistry, and is an effective way to manage and prevent common human diseases such as obesity, cardiovascular disorders and type II diabetes. However, the biomolecular mechanisms underlying such responses still need to be fully elucidated. Here we performed a transcriptome-wide analysis of skeletal muscle tissue in a large cohort of untrained Thoroughbred horses (n = 51) before and after a bout of high-intensity exe...
Geor RJ, Harris P.Insulin resistance (IR) and hyperinsulinemia increase risk for development of laminitis in horses and ponies. Obesity also has been associated with heightened risk for laminitis, likely by means of development of IR. Dietary factors, particularly the nonstructural carbohydrate (NSC) load, modulate risk for laminitis in these animals by means of exacerbation of IR or gastrointestinal disturbances that trigger the condition. Specific dietary management strategies to lessen risk for laminitis include caloric restriction to promote weight loss and improve insulin sensitivity in obese animals and s...
Tennent-Brown BS, Wilkins PA, Lindborg S, Russell G, Boston RC.Sequential lactate concentration ([LAC]) measurements have prognostic value in that hospitalized humans and neonatal foals that have a delayed return to normolactatemia have greater morbidity and case fatality rate. Objective: Prognosis for survival is decreased in horses with a delayed return to normal [LAC]. Methods: Two hundred and fifty adult horses presented for emergency evaluation excepting horses evaluated because of only ophthalmologic conditions, superficial wounds, and septic synovitis without systemic involvement. Methods: Prospective observational study. [LAC] was measured at admi...
Fitzgerald DM, Anderson ST, Sillence MN, de Laat MA.Generalized obesity, regional adiposity, hyperinsulinemia and hypertriglyceridemia are all potential indicators of equine metabolic syndrome (EMS). This study aimed to assess the relationship between morphometric measurements of body condition and metabolic hormone concentrations in ponies, with and without a neck crest or generalised obesity. Twenty-six ponies were assigned a body condition score (BCS) and cresty neck score (CNS). Height, girth, and neck measurements were taken. An oral glucose test (OGT; 0.75g dextrose/kg BW) was performed and blood samples collected prior to and 2 hours pos...
