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Grob AJ, Delarocque J, Feige K, Warnken T. Evaluating insulindysregulation in horses: A two-step insulin-tolerance test using porcine zinc insulin. Vet J 2024; 306:106172. [PMID: 38909714 DOI: 10.1016/j.tvjl.2024.106172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 05/22/2024] [Accepted: 06/12/2024] [Indexed: 06/25/2024]
Abstract
In insulin dysregulation, hyperinsulinemia (HI) can be accompanied by peripheral insulin resistance (IR) in horses, which can be diagnosed with an insulin-tolerance test (ITT). The administration of 0.1 IU/kg body weight of recombinant regular human insulin (RHI) should elicit a 50 % reduction of the initial blood glucose concentration at 30 min after insulin administration in insulin sensitive horses. Compared to RHI, porcine zinc insulin (PZI) is veterinary-approved and therefore easier accessible for many practitioners. The aim of this study was to compare the insulin and glucose dynamics during a standard ITT with RHI to an ITT performed with PZI. Twelve Icelandic horses were subjected to an ITT with RHI (ITT-RHI) and with PZI (ITT-PZI) at same dosages in a randomised crossover design. The insulin and glucose dynamics that resulted from these tests were compared, and the consistency of classification into insulin-sensitive and IR categories was evaluated. No complications were observed with the use of either RHI or PZI in ITT. A good correlation of the test results was observed (r = 0.88; P < 0.001). The blood glucose concentrations and the percentage reduction in glucose concentration did not differ significantly between the two tests (P = 0.053), but four out of twelve horses were classified as IR in the ITT-RHI whereas with the ITT-PZI seven out of twelve horses were classified as IR with the 50 % glucose reduction from baseline. Based on the Youden index, when using the ITT-PZI, an adjusted cut-off value for blood glucose reduction of 40 % at 30 min resulted in better test performance. With consideration for the seemingly weaker effect of PZI and the adjusted cut-off value, PZI can be an appropriate substitute to RHI in an ITT.
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Affiliation(s)
- A J Grob
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, Hannover 30559, Germany.
| | - J Delarocque
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, Hannover 30559, Germany
| | - K Feige
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, Hannover 30559, Germany
| | - T Warnken
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, Hannover 30559, Germany; Boehringer Ingelheim Vetmedica GmbH, Binger Straße 173, Ingelheim am Rhein 55263, Germany
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2
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Palhano RLA, Martins RA, Lemos GS, Faleiros RR, da Fonseca LA, Gorza LL, Lopes CEB, Meneses RM, de Carvalho AU, Filho EJF, Moreira TF. Exploring the impact of high-energy diets on cattle: Insights into subacute rumen acidosis, insulin resistance, and hoof health. J Dairy Sci 2024; 107:5054-5069. [PMID: 38460875 DOI: 10.3168/jds.2023-24151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 02/07/2024] [Indexed: 03/11/2024]
Abstract
Cattle lameness remains a significant concern, causing economic losses and compromising animal welfare. Claw horn lesions have been identified as a major cause of lameness in dairy cows, but their correlation with high-energy diets and ruminal acidosis remains unclear. Hence, the primary objective of this study was to assess the effects of a high-starch diet and a conventional diet on the rumen environment, acute-phase proteins, and metabolic alterations, with a particular focus on insulin resistance and the consequent implications for the histology of the hooves in Holstein steers. A total of 16 animals were divided into the high-starch (HS; 37% starch) and conventional (CON; 16.8% starch) groups. Glucose tolerance tests (GTT), blood analyses, rumen fluid analyses, and histological evaluations of the hoof tissue were conducted over a 102-d experimental period. The HS group showed a lower ruminal pH than the CON group, and with values indicating SARA. The plasma glucose and IGF-1 concentrations were higher in the HS group, suggesting an anabolic state. Both groups exhibited an increase in the insulin area under the curve (AUC) after the GTT on d 102. Histological analysis of the hooves showed a reduction in the length and width of the epidermal lamella in both groups. We found a significant negative correlation between the insulin AUC and the length and width of the epidermal lamella. Because both groups were similarly affected, the hypothesis that histological alterations were caused by the experimental diets still needs confirmation. Additionally, the development of SARA was not essential for the observed histological changes in the hoof. Further studies are warranted to thoroughly investigate the role of insulin and IGF-1 imbalances in claw health.
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Affiliation(s)
- Rodrigo L A Palhano
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Ronaldo A Martins
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Guilherme S Lemos
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Rafael R Faleiros
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil; Equinova Research Group, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Leandro A da Fonseca
- Veterinary Departament, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
| | - Leonardo L Gorza
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Carlos E B Lopes
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Rodrigo M Meneses
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Antônio U de Carvalho
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Elias J F Filho
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil
| | - Tiago F Moreira
- Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais 31270-901, Brazil.
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3
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Pratt-Phillips S. Effect of Exercise Conditioning on Countering the Effects of Obesity and Insulin Resistance in Horses-A Review. Animals (Basel) 2024; 14:727. [PMID: 38473112 DOI: 10.3390/ani14050727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/16/2024] [Accepted: 02/18/2024] [Indexed: 03/14/2024] Open
Abstract
Obesity is an important health concern in horses, along with humans and companion animals. Adipose tissue is an inflammatory organ that alters the insulin-signaling cascade, ultimately causing insulin dysregulation and impaired glucose metabolism. These disruptions can increase the risk of metabolic disease and laminitis in horses and may also impact energy metabolism during exercise. A single bout of exercise, along with chronic exercise conditioning, increases insulin sensitivity and glucose disposal via both contraction- and insulin-mediated glucose uptake pathways. Regular exercise also increases calorie expenditure, which can facilitate weight (as body fat) loss. This paper explores the metabolic pathways affected by adiposity, as well as discusses the impact of exercise on insulin metabolism in horses.
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de Laat MA, Sillence MN. Diagnosis of equine endocrinopathies: The value of measuring blood glucose during an oral glucose test. Vet J 2023; 300-302:106034. [PMID: 37778651 DOI: 10.1016/j.tvjl.2023.106034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 09/18/2023] [Accepted: 09/27/2023] [Indexed: 10/03/2023]
Abstract
Blood glucose concentration is often measured during an oral glucose test (OGT), but is not thought to aid in diagnosing insulin dysregulation (ID) or pituitary pars intermedia dysfunction (PPID). The aim of this retrospective study was to investigate whether the change in blood glucose concentration during an OGT aligned with indicators of equine metabolic syndrome or PPID, including serum insulin and plasma ACTH concentrations, clinical observations, age, sex, breed type and the test dose. The cohort included 149 horses, miniature horses, and ponies that had undergone an in-feed OGT and clinical examination between 2015 and 2021. The animals were diagnosed as either metabolically healthy, insulin-dysregulated, having PPID or both endocrinopathies. The mean ± standard error increase in blood glucose during the OGT was 3.41 ± 0.21 mM, and this change showed a weak positive correlation with the increase in serum insulin concentration (r = 0.36; P 0.001), body condition score (BCS; r = 0.26; P = 0.002) and cresty neck score (CNS; r = 0.38; P 0.001). The median [interquartile range] increase in blood glucose for miniature horses (5.25 [2.98-6.5] mM), was more than twice that seen in full-sized horses (2.4 [1.33-3.45] mM; P = 0.03). In metabolically healthy animals the increase in blood glucose during an OGT (+2.2 [1-3.5] mM) was smaller (P 0.001) than in animals with ID (+3.8 [2.73-5.33] mM), or both endocrine diseases (+6.1 [3.6-6.85] mM). There was an effect of the dose of dextrose on the blood glucose response, with higher doses yielding larger responses (P 0.001). The variability in these data support that basal and post-prandial blood glucose responses to an OGT are not appropriate as stand-alone diagnostic markers of ID or PPID. However, the association between blood glucose and CNS supports the use of CNS when evaluating animals for ID.
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Affiliation(s)
- M A de Laat
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland 4001, Australia.
| | - M N Sillence
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland 4001, Australia
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Malacarne BD, Martins RR, Paz CFR, Alves JVA, Dias LA, Cavalcante MA, Santos AM, Silva AGM, Leise BS, Carvalho AM, Faleiros RR. Histological comparison of the lamellar tissue of Iberian origin breed horses created in semi-feral conditions or in an intensive system. PLoS One 2023; 18:e0286536. [PMID: 37262053 DOI: 10.1371/journal.pone.0286536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 05/17/2023] [Indexed: 06/03/2023] Open
Abstract
Although the external conformation of wild horse hooves has been proposed as an ideal model for domesticated modern horses, histological signs of laminitis have been reported among them. With the hypothesis that the lamellar tissue of horses of Iberian origin raised in semi-feral is healthier than those raised in an intensive management system (stall confinement and high-calorie diet intake), the objective was to compare their lamellar tissues. Lamellar tissue samples were taken from the forelimb hoof of eight domesticated Mangalarga Marchador (MM) horses and from six semi-feral Marajoara (MJ) and Puruca (MP) horses. Primary epidermal lamella (PEL) and secondary epidermal lamella (SEL) were measured (length and width) in several regions, and their shapes were morphologically classified into different types. Breed groups were compared using analysis of variance, followed by Tukey or Dunn tests (P<0.05). Early signs of laminitis such as abnormal keratinization of the abaxial primary dermal lamella, tapered tips of the axial PELs, pointed tips of the SEL, nuclei condensation, and abnormal spatial orientation of the secondary epidermal basal cells (SELBC), were seen only in MM horses. MP horses had a greater interface of epidermis/dermis contact than MJ horses and more rounded nuclei in the round SELBC than MM horses. In agreement with the study hypothesis, semi-feral MJ and MP horses' lamellae were classified as healthier than MM horses, which showed early signs of endocrinopathic laminitis.
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Affiliation(s)
- Bruno Dondoni Malacarne
- Marion DuPont Equine Medical Center, Virginia Tech, Leesburg, Virginia, United States of America
- Equinova Research Group, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo Ribeiro Martins
- Equinova Research Group, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Centro Universitário de Mineiros-UNIFIMES, Mineiros, Goiás, Brazil
| | - Cahuê Francisco Rosa Paz
- Equinova Research Group, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Lucas Antunes Dias
- Equinova Research Group, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Alison Miranda Santos
- Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal, Pará, Brazil
| | | | - Britta Sigrid Leise
- Veterinary Clinical Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
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McGowan CM, Ireland JL. Equine Endocrine Disease: Challenges With Case Definition for Research. J Equine Vet Sci 2023; 124:104491. [PMID: 37236726 DOI: 10.1016/j.jevs.2023.104491] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/06/2023] [Accepted: 04/12/2023] [Indexed: 05/28/2023]
Abstract
Equine endocrine disease is an important area for equine research, requiring an appropriate case definition for inclusion and criteria for exclusion from disease. Defining a case for research may be different from criteria for clinical diagnosis. Further, clinical diagnosis recommendations have been changing regularly, making this area challenging for equine scientists. This review discusses the diagnosis of major equine endocrine diseases, pituitary pars intermedia dysfunction, equine metabolic syndrome and insulin dysregulation, focusing on the most appropriate diagnostic methods for research case definitions. Different diagnostic methods, including use of reference intervals and clinical decision limits, will be discussed with their relative merits for use in case definition for research.
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Affiliation(s)
- Catherine M McGowan
- School of Veterinary Science, Institute of Infection, Ecological and Veterinary Sciences, the University of Liverpool, Neston, UK.
| | - Joanne L Ireland
- School of Veterinary Science, Institute of Infection, Ecological and Veterinary Sciences, the University of Liverpool, Neston, UK
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Elliott J, Bailey SR. A review of cellular and molecular mechanisms in endocrinopathic, sepsis-related and supporting limb equine laminitis. Equine Vet J 2023; 55:350-375. [PMID: 36847165 DOI: 10.1111/evj.13933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 02/23/2023] [Indexed: 03/01/2023]
Abstract
Equine laminitis has both fascinated and frustrated veterinary researchers and clinicians for many years. The recognition that many ponies suffering from pasture-associated laminitis have an insulin-dysregulated phenotype (endocrinopathic laminitis, EL) and that prolonged insulin and glucose infusions can experimentally induce laminar pathology and functional failure are seminal discoveries in this field. Researchers have studied the molecular basis for disease pathogenesis in models of EL, sepsis-related laminitis and supporting limb laminitis and generated much data over the last 15 years. This review attempts to synthesise those data, drawing comparisons between models and naturally occurring laminitis. A hypothesis is proposed that the basal epithelial cell stress is a central event in each category of laminitis. Furthermore, in naturally occurring pasture-associated laminitis, pathways that predominate in each type of laminitis contribute to laminar lamellar pathology to varying extents. Based on the molecular mechanisms determined in experimental models, interactions between these pathways are identified.
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Affiliation(s)
- Jonathan Elliott
- Department of Comparative Biomedical Sciences, The Royal Veterinary College University of London, London, UK
| | - Simon R Bailey
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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de Tonnerre DJ, Medina Torres CE, Stefanovski D, Robinson MA, Kemp KL, Bertin FR, van Eps AW. Effect of sirolimus on insulin dynamics in horses. J Vet Intern Med 2023; 37:703-712. [PMID: 36840433 DOI: 10.1111/jvim.16650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 02/01/2023] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND Sirolimus, a mechanistic target of rapamycin inhibitor, suppresses insulin production in other species and has therapeutic potential for hyperinsulinemia in horses. HYPOTHESIS/OBJECTIVE Determine the pharmacokinetics (PKs) of sirolimus and evaluate its effect on insulin dynamics in healthy and insulin dysregulation (ID) horses. ANIMALS Eight Standardbred geldings. METHODS A PK study was performed followed by a placebo-controlled, randomized, crossover study. Blood sirolimus concentrations were measured by liquid chromatography-mass-spectrometry. PK indices were estimated by fitting a 2-compartment model using nonlinear least squares regression. An oral glucose test (OGT) was conducted before and 4, 24, 72, and 144 hours after administration of sirolimus or placebo. Effects of time, treatment and animal on blood glucose and insulin concentrations were analyzed using mixed-effects linear regression. Sirolimus was then administered to 4 horses with dexamethasone-induced ID and an OGT was performed at baseline, after ID induction and after 7 days of treatment. RESULTS Median (range) maximum sirolimus concentration was 277.0 (247.5-316.06) ng/mL at 5 (5-10) min and half-life was 3552 (3248-4767) min. Mean (range) oral bioavailability was 9.5 (6.8-12.4)%. Sirolimus had a significant effect on insulin concentration 24 hours after a single dose: median (interquartile range) insulin at 60 min (5.0 [3.7-7.0] μIU/mL) was 37 (-5 to 54)% less than placebo (8.7 [5.8-13.7] μIU/mL, P = .03); and at 120 min (10.2 [8.4-12.2] μIU/mL) was 28 (-15 to 53)% less than placebo (14.9 [8.4-24.8] μIU/mL, P = .02). There was minimal effect on glucose concentration. Insulin responses decreased toward baseline in ID horses after 7 days of treatment. CONCLUSION AND CLINICAL IMPORTANCE Sirolimus decreased the insulinemic response to glucose and warrants further investigation.
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Affiliation(s)
- Demia J de Tonnerre
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | | | - Darko Stefanovski
- Department of Clinical Studies - New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - Mary A Robinson
- Department of Clinical Studies - New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - Kate L Kemp
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - François-René Bertin
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Andrew W van Eps
- Department of Clinical Studies - New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
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Burns TA, Watts MR, Belknap JK, van Eps AW. Digital lamellar inflammatory signaling in an experimental model of equine preferential weight bearing. J Vet Intern Med 2023; 37:681-688. [PMID: 36840365 DOI: 10.1111/jvim.16662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 02/03/2023] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND Supporting limb laminitis (SLL) is a complication of severe orthopedic disease in horses and is often life-limiting, yet the pathophysiology remains obscure. HYPOTHESIS/OBJECTIVES To investigate the role of digital lamellar inflammatory signaling in the pathophysiology of SLL using a model of unilateral weight bearing, hypothesizing that there would be evidence of lamellar inflammation in limbs subjected to the model. ANIMALS Thirteen healthy adult Standardbred horses were used for this study (11 geldings, 2 mares; mean age 6.5 ± 2.5 years; mean body weight 458.3 ± 32.8 kg). METHODS Randomized controlled experimental study. A steel shoe with a custom insert was applied to a randomly selected front foot of 7 horses; 6 horses were unshod and served as controls. After 92 hours, all horses were humanely euthanized, and digital lamellar samples were collected. Lamellar protein and mRNA were isolated and used to perform western blot and PCR. RESULTS Lamellar concentrations of IL-6 mRNA were higher in SL tissue than IL HIND tissue (median [25%-75%] normalized copy number 191 [111-3060] and 48 [25-74], respectively; P=.003), and lamellar concentrations of COX-2 mRNA were higher in SL tissue than CON tissue (normalized copy number 400 [168-634] and 125 [74-178], respectively; P=.007). Lamellar concentrations of IL-1B, IL-10, and COX-1 mRNA were not significantly different between groups. The concentrations of phosphorylated (activated) STAT1 and STAT3 proteins were higher in SL (0.5 [0.35-0.87] and 1.35 [1.1-1.7], respectively) compared to CON (0.24 [0.09-0.37] and 0.31 [0.16-037]) and UL HIND (0.27 [0.19-0.37] and 0.38 [0.24-0.5]); P=0.01 and P<0.001. CONCLUSIONS AND CLINICAL IMPORTANCE Lamellar inflammatory signaling was higher in tissue from horses subjected to prolonged unilateral weight-bearing, suggesting that these pathways could be relevant to the pathophysiology of SLL.
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Affiliation(s)
- Teresa A Burns
- The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA
| | - Mauria R Watts
- The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA
| | - James K Belknap
- The Ohio State University College of Veterinary Medicine, Columbus, Ohio, USA
| | - Andrew W van Eps
- School of Veterinary Science, University of Queensland, Gatton, Queensland, Australia.,School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA
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de Laat MA, Fitzgerald DM, Harris PA, Bailey SR. A glucagon-like peptide-1 receptor antagonist reduces the insulin response to a glycemic meal in ponies. J Anim Sci 2023; 101:skad389. [PMID: 38066683 PMCID: PMC10724109 DOI: 10.1093/jas/skad389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
High plasma concentrations of insulin can cause acute laminitis. Ponies and horses with insulin dysregulation (ID) exhibit marked hyperinsulinemia in response to dietary hydrolyzable carbohydrates. Glucagon-like peptide-1 (GLP-1), an incretin hormone released from the gastrointestinal tract, enhances insulin release, and is increased postprandially in ponies with ID. The aim of this study was to determine whether blocking the GLP-1 receptor reduces the insulin response to a high glycemic meal. Five adult ponies were adapted to a cereal meal and then given two feed challenges 24 h apart of a meal containing 3 g/kg BW micronized maize. Using a randomized cross-over design all ponies received both treatments, where one of the feeds was preceded by the IV administration of a GLP-1 receptor blocking peptide, Exendin-3 (9-39) amide (80 µg/kg), and the other feed by a sham treatment of peptide diluent only. Blood samples were taken before feeding and peptide administration, and then at 30-min intervals via a jugular catheter for 6 h for the measurement of insulin, glucose, and active GLP-1. The peptide and meal challenge caused no adverse effects, and the change in plasma glucose in response to the meal was not affected (P = 0.36) by treatment: peak concentration 9.24 ± 1.22 and 9.14 ± 1.08 mmol/L without and with the antagonist, respectively. Similarly, there was no effect (P = 0.35) on plasma active GLP-1 concentrations: peak concentration 14.3 ± 1.36 pM and 13.7 ± 1.97 pM without and with the antagonist, respectively. However, the antagonist caused a significant decrease in the area under the curve for insulin (P = 0.04), and weak evidence (P = 0.06) of a reduction in peak insulin concentration (456 ± 147 μIU/mL and 370 ± 146 μIU/mL without and with the antagonist, respectively). The lower overall insulin response to the maize meal after treatment with the antagonist demonstrates that blocking the GLP-1 receptor partially reduced insulin production in response to a high starch, high glycemic index, diet. Using a different methodological approach to published studies, this study also confirmed that GLP-1 does contribute to the excessive insulin production in ponies with ID.
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Affiliation(s)
- Melody A de Laat
- Faculty of Science, Queensland University of Technology, Brisbane, QLD, Australia
| | | | - Patricia A Harris
- Equine Studies Group, Waltham Petcare Science Institute, Melton Mowbray, UK
| | - Simon R Bailey
- Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
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Manfredi JM, Jacob S, Norton E. A one-health lens offers new perspectives on the importance of endocrine disorders in the equine athlete. J Am Vet Med Assoc 2023; 261:153-164. [PMID: 36595370 DOI: 10.2460/javma.22.11.0485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
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 current comparative research so that veterinarians can employ cutting-edge preventative, diagnostic, and therapeutic recommendations. Identified key gaps in knowledge include whether equine metabolic osteoarthritis exists, if steroid joint injections are safe in horses with endocrine disorders, and if the return to performance percentage improves with concurrent treatment of endocrine and musculoskeletal disorders. Key takeaways include that the relationship between endocrine disorders and musculoskeletal disease in the horse goes beyond laminitis to include lameness, muscle atrophy, suspensory ligament degeneration, osteochondritis dissecans, and potentially metabolic osteoarthritis. Approaches learned from human and equine comparative studies can offer insight into injury recognition and management, thus mitigating the impact of endocrine disorders on performance in both species. Readers interested in an in-depth description of current and future research involving pathophysiology, novel interventions, and multiomic approaches to identify individuals with athletic limitations induced by endocrine disorders are invited to read the companion Currents in One Health by Manfredi et al, AJVR, February 2023.
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Affiliation(s)
- Jane M Manfredi
- 1Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI
| | - Sarah Jacob
- 1Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI
| | - Elaine Norton
- 2Department of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ
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12
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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, Sonntag J. Carbohydrate pellets to assess insulin dysregulation in horses. Vet Med (Auckl) 2022; 37:302-314. [PMID: 36583553 PMCID: PMC9889680 DOI: 10.1111/jvim.16621] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 12/14/2022] [Indexed: 12/31/2022]
Abstract
BACKGROUND 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. HYPOTHESIS/OBJECTIVES 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. ANIMALS University and privately-owned horses and ponies (n = 157) comprised of 31 breeds and both sexes. METHODS Multicenter cohort study. A custom-produced glycemic pellet was offered for free intake at 0.5 g/kg BW soluble carbohydrate and serum insulin and blood glucose concentrations measured before and after (60, 120, and 180 minutes) the pellets were offered. Pellet acceptance and intake time (those that finished within 10 minutes) were determined to assess palatability. RESULTS The pellets were palatable to 132/157 animals, and ponies found the pellets more (P = .004) palatable than horses. The median intake time (4 [3-6] minutes) was positively correlated with acceptance grade (r = .51; P < .0001). Consumption of the pellets elicited peak blood glucose (6.6 [5.8-7.8] mmol/L) and serum insulin (40.5 [19-99.8] μIU/mL) responses at 120 minutes. At 120 minutes the optimal cut-off was 83 μIU/mL (95% CI: 70-99 μIU/mL) for the IMMULITE 2000XPi assay. CONCLUSIONS AND CLINICAL IMPORTANCE The pellets were palatable and a suitable, novel carbohydrate source for the OGT.
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Affiliation(s)
- Melody A. de Laat
- Faculty of ScienceQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Tobias Warnken
- Boehringer Ingelheim Vetmedica GmbHIngelheimGermany,Clinic for HorsesUniversity of Veterinary MedicineHannoverGermany
| | | | | | - Anne J. Grob
- Clinic for HorsesUniversity of Veterinary MedicineHannoverGermany
| | - Karsten Feige
- Clinic for HorsesUniversity of Veterinary MedicineHannoverGermany
| | - Harry B. Carslake
- Institute of Infection, Veterinary and Ecological SciencesUniversity of LiverpoolLiverpoolUK
| | | | - Martin N. Sillence
- Faculty of ScienceQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Kristen E. Thane
- Department of Comparative PathobiologyCummings School of Veterinary Medicine, Tufts UniversityNorth GraftonMassachusettsUSA
| | - Nicholas Frank
- Department of Comparative PathobiologyCummings School of Veterinary Medicine, Tufts UniversityNorth GraftonMassachusettsUSA
| | - Johan Brojer
- Department of Clinical SciencesSwedish University of Agricultural SciencesUppsalaSweden
| | - Sanna Lindase
- Department of Clinical SciencesSwedish University of Agricultural SciencesUppsalaSweden
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13
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Plasma Amino Acid Concentration in Obese Horses with/without Insulin Dysregulation and Laminitis. Animals (Basel) 2022; 12:ani12243580. [PMID: 36552500 PMCID: PMC9774246 DOI: 10.3390/ani12243580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/09/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
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 (IDL). Significant differences in the resting concentrations between obese and insulin dysregulated and laminitic (citrulline p = 0.038, obese: 73.001 ± 12.661 nmol/mL, IDL: 49.194 ± 15.486 nmol/mL; GABA p = 0.02, obese: 28.234 ± 3.885 nmol/mL, IDL: 16.697 ± 1.679 nmol/mL; methionine p = 0.018, obese: 28.691 ± 5.913 nmol/mL, IDL: 20.143 ± 3.09 nmol/mL) as well as between insulin dysregulated individuals with and without laminitis (GABA p < 0.001, ID: 28.169 ± 6.739 nmol/mL) regarding three amino acids were determined. This may be an interesting approach, especially for diagnostic testing and possibly also for the feed supplements of horses at risk of developing laminitis. However, further research, including a higher number of cases, is required.
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14
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Sundberg JP, Galantino-Homer H, Fairfield H, Ward-Bailey PF, Harris BS, Berry M, Pratt CH, Gott NE, Bechtold LS, Kaplan PR, Durbin-Johnson BP, Rocke DM, Rice RH. Witch Nails (Krt90whnl): A spontaneous mouse mutation affecting nail growth and development. PLoS One 2022; 17:e0277284. [PMID: 36374931 PMCID: PMC9662738 DOI: 10.1371/journal.pone.0277284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/25/2022] [Indexed: 11/16/2022] Open
Abstract
Numerous single gene mutations identified in humans and mice result in nail deformities with many similarities between the species. A spontaneous, autosomal, recessive mutation called witch nails (whnl) is described here where the distal nail matrix and nail bed undergo degenerative changes resulting in formation of an abnormal nail plate causing mice to develop long, curved nails. This mutation arose spontaneously in a colony of MRL/MpJ-Faslpr/J at The Jackson Laboratory. Homozygous mutant mice are recognizable by 8 weeks of age by their long, curved nails. The whnl mutation, mapped on Chromosome 15, is due to a 7-bp insertion identified in the 3’ region of exon 9 in the Krt90 gene (formerly Riken cDNA 4732456N10Rik), and is predicted to result in a frameshift that changes serine 476 to arginine and subsequently introduces 36 novel amino acids into the protein before a premature stop codon (p. Ser476ArgfsTer36). By immunohistochemistry the normal KRT90 protein is expressed in the nail matrix and nail bed in control mice where lesions are located in mutant mice. Immunoreactivity toward equine KRT124, the ortholog of mouse KRT90, is restricted to the hoof lamellae (equine hoof wall and lamellae are homologous to the mouse nail plate and nail bed) and the mouse nail bed. Equine laminitis lesions are similar to those observed in this mutant mouse suggesting that the latter may be a useful model for hoof and nail diseases. This first spontaneous mouse mutation affecting the novel Krt90 gene provides new insight into the normal regulation of the molecular pathways of nail development.
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Affiliation(s)
- John P. Sundberg
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - Hannah Galantino-Homer
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, United States of America
| | - Heather Fairfield
- Maine Medical Center Research Institute, Scarborough, ME, United States of America
| | | | | | - Melissa Berry
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - C. Herbert Pratt
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - Nicholas E. Gott
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | | | - Pauline R. Kaplan
- Department of Environmental Toxicology, University of California, Davis, CA, United States of America
| | - Blythe P. Durbin-Johnson
- Department of Applied Biosciences, University of California, Davis, CA, United States of America
| | - David M. Rocke
- Department of Applied Biosciences, University of California, Davis, CA, United States of America
| | - Robert H. Rice
- Department of Environmental Toxicology, University of California, Davis, CA, United States of America
- * E-mail:
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15
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Lean NE, Zedler ST, Van Eps AW, Engiles JB, Ford M, Stefanovski D, Walsh DM, Pollitt CC. Evaluation of locking compression plate fixation of the distal phalanx to the hoof wall as a potential therapy for laminitis. Equine Vet J 2022. [DOI: 10.1111/evj.13877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 08/11/2022] [Indexed: 11/28/2022]
Affiliation(s)
- N. E. Lean
- School of Veterinary Science University of Queensland Gatton QLD Australia
| | - S. T. Zedler
- School of Veterinary Science University of Queensland Gatton QLD Australia
| | - A. W. Van Eps
- New Bolton Centre, Department of Clinical Studies, School of Veterinary Medicine University of Pennsylvania Kennett Square PA USA
| | - J. B. Engiles
- New Bolton Centre, Department of Clinical Studies, School of Veterinary Medicine University of Pennsylvania Kennett Square PA USA
| | - M. Ford
- New Bolton Centre, Department of Clinical Studies, School of Veterinary Medicine University of Pennsylvania Kennett Square PA USA
| | - D. Stefanovski
- New Bolton Centre, Department of Clinical Studies, School of Veterinary Medicine University of Pennsylvania Kennett Square PA USA
| | | | - C. C. Pollitt
- School of Veterinary Science University of Queensland Gatton QLD Australia
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16
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The Differences in Histoarchitecture of Hoof Lamellae between Obese and Lean Draft Horses. Animals (Basel) 2022; 12:ani12141774. [PMID: 35883323 PMCID: PMC9311632 DOI: 10.3390/ani12141774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/23/2022] [Accepted: 06/29/2022] [Indexed: 11/17/2022] Open
Abstract
Obesity is a common problem in horses. The associations between obesity and equine metabolic syndrome (EMS) and between EMS and laminitis are known. However, there is a lack of data on whether obesity itself can affect hoof lamellae. Forelimbs and blood from 12 draft horses (six obese and six lean) from a slaughterhouse were acquired. To exclude laminitis and EMS horses, insulin concentration was measured, and hooves were radiographed. Histological evaluation was performed. The shape of the primary and secondary epidermal lamellae (PEL and SEL) was evaluated, and the length of the keratinized and total primary epidermal lamellae was measured (KPEL and TEL). All horses showed pathological changes in lamellae. In the lean group, the changes were longer SELs, more proliferated and separated PDLs, and less standard PDLs. In the obese group, the changes were a lower number of club-shaped and standard SELs and significantly more tapered SELs. No difference in the shape of PELs and the length of KPELs was noticed. The research did not confirm the effects of obesity on lamellar failure. The measurements taken indicate that the lamellae are much longer compared to other research studies; this could indicate that the length of the PEL depends on the hoof size.
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17
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Mechanical nociceptive assessment of the equine hoof after navicular bursa anesthetic infiltration validated by bursography. PLoS One 2022; 17:e0269532. [PMID: 35671268 PMCID: PMC9173607 DOI: 10.1371/journal.pone.0269532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 05/23/2022] [Indexed: 12/03/2022] Open
Abstract
The analgesic specificity of navicular bursa (NB) anesthetic infiltration is still questionable. The study aimed to determine the mechanical nociceptive threshold of non-specific analgesia in the dorsal lamellar stratum, as well as in the sole, coronary band, and heel bulbs of the hoof, after navicular bursa anesthetic infiltration. Six healthy horses with no clinical or radiographic changes of the digits and no communication between the NB and the distal interphalangeal joint, were used. After random selection, the NB of one of the forelimbs was infiltrated with 2% lidocaine and the contralateral one with lactated ringer’s solution. Contrast was added to confirm radiographic infiltration. The mechanical nociceptive threshold was determined using a portable pressure dynamometer, before and at various times after the infiltration, in 10 points of the hoof. The effects of time and treatment were verified by ANOVA (P<0.05). There was no statistical difference in the values of the mechanical nociceptive threshold (P>0.05) in all regions evaluated. However, in one of the six hooves that receives lidocaine, complete absence of response to the painful stimulus (maximum force of 6 Kg over an area of 38.46 mm2, for a maximum of 4 seconds) was observed in the dorsal lamellae between 30 and 60 min after infiltration. In conclusion, lidocaine infiltration of NB did not promote significant increases in the nociceptive threshold of the sole, coronary band, bulbs of the heel and dorsal lamellae clinically healthy horses. However, the occurrence of analgesia in one of the six hooves subjected to NB anesthesia indicates that the technique may not be fully specific in few horses.
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18
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Storms N, Medina Torres C, Franck T, Sole Guitart A, de la Rebière G, Serteyn D. Presence of Myeloperoxidase in Lamellar Tissue of Horses Induced by an Euglycemic Hyperinsulinemic Clamp. Front Vet Sci 2022; 9:846835. [PMID: 35359667 PMCID: PMC8962398 DOI: 10.3389/fvets.2022.846835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Laminitis is a pathology of the equine digit leading to a failure of the dermo-epidermal interface. Neutrophil activation is recognized as a major factor in SIRS-associated laminitis. Less is known about the role of neutrophil activation in laminitis associated with metabolic disorders. The aim of this descriptive study was to observe whether myeloperoxidase is increased in the laminae during early stage laminitis in three horses subjected to a prolonged euglycemic hyperinsulinemic clamp (pEHC). After 48 h of pEHC-treatment, horses were subjected to euthanasia. Two healthy horses are used as control. Histological sections of lamellar tissue from all horses were immunohistochemically stained for myeloperoxidase and counterstained with hematoxylin-eosin. Histopathological changes that characterize insulin-induced laminitis and increased presence of myeloperoxidase, especially in the dermal lamellae, were increased in histologic sections of pEHC-treated horses. Neutrophil myeloperoxidase release may contribute to the pathophysiology of endocrinopathic laminitis.
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Affiliation(s)
- Nazare Storms
- Department of Equine Surgery, University of Liège, Liège, Belgium
| | - Carlos Medina Torres
- School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia
| | - Thierry Franck
- Center for Oxygen Research and Development, FARAH, University of Liège, Liège, Belgium
| | - Albert Sole Guitart
- School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia
| | | | - Didier Serteyn
- Department of Equine Surgery, University of Liège, Liège, Belgium
- Center for Oxygen Research and Development, FARAH, University of Liège, Liège, Belgium
- *Correspondence: Didier Serteyn
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19
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Grenager NS. Endocrinopathic Laminitis. Vet Clin North Am Equine Pract 2021; 37:619-638. [PMID: 34674908 DOI: 10.1016/j.cveq.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Endocrinopathic laminitis (EL) primarily occurs because of insulin dysregulation (ID) mediated through downstream effects of insulin on IGF-1R in lamellar tissues. There is likely contributing vascular and metabolic dysfunction within the lamellae, but EL is relatively non-inflammatory. EL is associated with lamellar stretching, proliferation, and failure, ultimately causing failure of the suspensory apparatus of the distal phalanx. Proper education regarding mitigating risk factors makes this a largely preventable cause of laminitis. Annual hoof evaluation plus screening geriatric horses for pituitary pars intermedia dysfunction and ID, and younger horses for ID, can significantly decrease the incidence of this devastating condition.
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Affiliation(s)
- Nora S Grenager
- Steinbeck Peninsula Equine Clinics, 100 Ansel Lane, Menlo Park, CA 94028, USA.
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20
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Bennett M, McGowan CM. Science-in-brief: Report on the Global Equine Endocrinology Symposium. Equine Vet J 2021; 53:414-416. [PMID: 33834533 DOI: 10.1111/evj.13405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/09/2020] [Accepted: 12/12/2020] [Indexed: 01/01/2023]
Affiliation(s)
- Marcus Bennett
- Boehringer Ingelheim Animal Health UK Ltd, Bracknell, UK
| | - Catherine M McGowan
- University of Liverpool, Department of Equine Clinical Science, Institute of Infection, Veterinary and Ecological Sciences, Neston, UK
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21
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Translating research into practice: Adoption of endocrine diagnostic testing in cases of equine laminitis. Vet J 2021; 272:105656. [PMID: 33941328 DOI: 10.1016/j.tvjl.2021.105656] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/01/2021] [Accepted: 03/15/2021] [Indexed: 01/19/2023]
Abstract
Research demonstrating insulin's causal role in endocrinopathic laminitis has greatly advanced understanding of equine laminitis. However, the degree to which this knowledge has been translated into clinical practice has not been assessed. This two-part study aimed to investigate veterinary surgeons' current diagnostic approach to laminitis, whether this had changed over time, and the impact of diagnosing an endocrinopathy on laminitis case management and outcome. Two cross-sectional online surveys of equine veterinary surgeons working within the UK were undertaken. The first study population comprised 141 veterinary surgeons, who had graduated a median of 8 years previously. Overall, 83.6% of respondents (n = 117/140) had changed their diagnostic approach to laminitis since graduating, primarily through increasing use of endocrine testing (88.7%; n = 86/97). Ninety-nine percent (n = 140/141) performed endocrine diagnostic test(s) for some or all laminitis cases at initial and/or subsequent examinations. The second study had 120 participating veterinary surgeons, ≥76% of whom considered diagnosing underlying endocrine diseases greatly influenced their laminitis case management. Where an endocrinopathy was identified, 75.0% (n = 90/120) considered that client communication regarding laminitis was facilitated, and ≥67% considered that treating the endocrinopathy was effective in reducing laminitis recurrence. This study demonstrates successful translation of research knowledge into equine practice, with the vast majority of veterinary surgeons adopting endocrine diagnostic testing within their routine approach to laminitis cases. Respondents perceived that this change in diagnostic approach has resulted in improvements in several non-clinical and clinical healthcare outcomes, including client communication and reduction in recurrent laminitis episodes.
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22
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Stokes SM, Stefanovski D, Bertin FR, Medina-Torres CE, Belknap JK, van Eps AW. Plasma amino acid concentrations during experimental hyperinsulinemia in 2 laminitis models. J Vet Intern Med 2021; 35:1589-1596. [PMID: 33704816 PMCID: PMC8163125 DOI: 10.1111/jvim.16095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 02/14/2021] [Accepted: 02/19/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Endocrinopathic laminitis develops in association with insulin dysregulation, but the role of insulin in the pathogenesis remains unclear. Hyperinsulinemia can cause hypoaminoacidemia, which is associated with integumentary lesions in other species and therefore warrants investigation as a potential mechanism in laminitis. OBJECTIVE Evaluate plasma amino acid concentrations in the euglycemic-hyperinsulinemic clamp (EHC) and prolonged glucose infusion (PGI) laminitis models. ANIMALS Sixteen Standardbred horses. METHODS Prospective experimental study. Plasma amino acid concentrations were measured in samples collected every 6 hours from horses that underwent a 48-hour EHC (n = 8) or 66-hour PGI (n = 8) after a 24- or 6-hour baseline period in EHC and PGI groups, respectively. RESULTS Fifteen of the 20 measured amino acid concentrations decreased over time in both EHC and PGI horses (P < 0.001). The median percentage change from baseline for these amino acids was: histidine (EHC: 41.5%; PGI: 43.9%), glutamine (EHC: 51.8%; PGI: 35.3%), arginine (EHC: 51.4%; PGI: 41%), glutamic acid (EHC: 52.4%; PGI: 31.7%), threonine (EHC: 62.8%; PGI: 25.2%), alanine (EHC: 48.9%; PGI: 19.5%), proline (EHC: 56.2%; PGI: 30.3%), cystine (EHC: 34.9%; PGI: 31.2%), lysine (EHC: 46.4%; PGI: 27.8%), tyrosine (EHC: 27.5%; PGI: 16.9%), methionine (EHC: 69.3%; PGI: 50.8%), valine (EHC: 50.8%; PGI: 34.4%), isoleucine (EHC: 60.8%; PGI: 38.7%), leucine (EHC: 48.2%; PGI: 36.6%), and phenylalanine (EHC: 16.6%; PGI: 12.1%). CONCLUSIONS AND CLINICAL IMPORTANCE Hypoaminoacidemia develops in EHC and PGI laminitis models. The role of hypoaminoacidemia in the development of hyperinsulinemia-associated laminitis warrants further investigation.
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Affiliation(s)
- Simon M Stokes
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Darko Stefanovski
- Department of Clinical Studies, School of Veterinary Medicine, New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - François-René Bertin
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Carlos E Medina-Torres
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - James K Belknap
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Andrew W van Eps
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.,Department of Clinical Studies, School of Veterinary Medicine, New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
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23
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Tuniyazi M, He J, Guo J, Li S, Zhang N, Hu X, Fu Y. Changes of microbial and metabolome of the equine hindgut during oligofructose-induced laminitis. BMC Vet Res 2021; 17:11. [PMID: 33407409 PMCID: PMC7789226 DOI: 10.1186/s12917-020-02686-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 11/19/2020] [Indexed: 12/15/2022] Open
Abstract
Background Laminitis is a common and serve disease which caused by inflammation and pathological changes of the laminar junction. However, the pathologic mechanism remains unclear. In this study we aimed to investigate changes of the gut microbiota and metabolomics in oligofructose-induced laminitis of horses. Results Animals submitted to treatment with oligofructose had lower fecal pH but higher lactic acid, histamine, and Lipopolysaccharide (LPS) in serum. Meanwhile, oligofructose altered composition of the hindgut bacterial community, demonstrated by increasing relative abundance of Lactobacillus and Megasphaera. In addition, the metabolome analysis revealed that treatment with oligofructose decreased 84 metabolites while 53 metabolites increased, such as dihydrothymine, N3,N4-Dimethyl-L-arginine, 10E,12Z-Octadecadienoic acid, and asparagine. Pathway analysis revealed that aldosterone synthesis and secretion, regulation of lipolysis in adipocytes, steroid hormone biosynthesis, pyrimidine metabolism, biosynthesis of unsaturated fatty acids, and galactose metabolism were significantly different between healthy and laminitis horses. Furthermore, correlation analysis between gut microbiota and metabolites indicated that Lactobacillus and/or Megasphaera were positively associated with the dihydrothymine, N3,N4-Dimethyl-L-arginine, 10E,12Z-Octadecadienoic acid, and asparagine. Conclusions These results revealed that disturbance of gut microbiota and changes of metabolites were occurred during the development of equine laminitis, and these results may provide novel insights to detect biomarkers for a better understanding of the potential mechanism and prevention strategies for laminitis in horses. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-020-02686-9.
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Affiliation(s)
- Maimaiti Tuniyazi
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province, 130062, People's Republic of China
| | - Junying He
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province, 130062, People's Republic of China
| | - Jian Guo
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province, 130062, People's Republic of China
| | - Shuang Li
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province, 130062, People's Republic of China
| | - Naisheng Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province, 130062, People's Republic of China
| | - Xiaoyu Hu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province, 130062, People's Republic of China.
| | - Yunhe Fu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, Jilin Province, 130062, People's Republic of China.
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24
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Rahnama S, Spence R, Vathsangam N, Baskerville CL, Bailey SR, de Laat MA, Anderson ST, Pollitt CC, Sillence MN. Effects of insulin on IGF-1 receptors in equine lamellar tissue in vitro. Domest Anim Endocrinol 2021; 74:106530. [PMID: 32818904 DOI: 10.1016/j.domaniend.2020.106530] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 07/23/2020] [Accepted: 07/23/2020] [Indexed: 11/21/2022]
Abstract
Although it is understood that equine endocrinopathic laminitis can be triggered by high concentrations of insulin, it is unclear whether this represents a direct action on lamellar tissue via insulin receptors (InsR), an interaction with IGF-1 receptors (IGF-1R), or some other, indirect action. This uncertainty is because of the reported scarcity of InsR in lamellar tissue and the low affinity of insulin for equine IGF-1R. In the present study, the effects of insulin and IGF-1 (as a positive control) were examined using lamellar explants isolated from the hooves of healthy horses and incubated in cell culture medium for between 2 min and 48 h. In this system, a low physiological concentration of IGF-1 (10 nM; 1.31 ng/mL) caused a marked increase in the appearance of phosphorylated IGF-1R after 5 min (P < 0.05), and this effect was blocked by a human anti-IGF-1R monoclonal antibody (mAb). However, a high concentration of insulin (10 nM; 1,430 μIU/mL) appeared to cause dephosphorylation of the IGF-1R after 5 min (P < 0.01), 15 min, and 30 min (P < 0.001). Using 3H-thymidine as a marker, it was also demonstrated that insulin and IGF-1-stimulated cell proliferation in lamellar explants over the same concentration range as each other (1-100 nM), implying that each peptide acts via its own receptor (P < 0.001). Conversely, the effect of both peptides could be blocked using a selective anti-IGF-1R mAb (P < 0.001), implying that insulin acts via IGF1-R (either directly or indirectly). Notwithstanding this conundrum, the results demonstrate that insulin acts directly on lamellar tissue and suggest that a therapeutic anti-IGF-1R mAb could be useful in treating or preventing endocrinopathic laminitis.
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Affiliation(s)
- S Rahnama
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - R Spence
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - N Vathsangam
- Department of Veterinary Biosciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - C L Baskerville
- Department of Veterinary Biosciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - S R Bailey
- Department of Veterinary Biosciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - M A de Laat
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - S T Anderson
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - C C Pollitt
- School of Veterinary Science, The University of Queensland, Gatton, Australia
| | - M N Sillence
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia.
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Rahnama S, Vathsangam N, Spence R, Anderson ST, de Laat MA, Bailey S, Sillence MN. Identification of monoclonal antibodies suitable for blocking IGF-1 receptors in the horse. Domest Anim Endocrinol 2021; 74:106510. [PMID: 32652390 DOI: 10.1016/j.domaniend.2020.106510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/11/2020] [Accepted: 06/11/2020] [Indexed: 01/19/2023]
Abstract
Prolonged hyperinsulinemia is thought to be the cause of equine endocrinopathic laminitis, a common and crippling disease of the foot, for which there are no pharmacologic treatments other than pain relief. It has been suggested that insulin causes its effects on the lamellae by activating IGF-1 receptors (IGF-1R), as insulin receptors (InsR) are scarce in this tissue, whereas IGF-1R are abundant and become downregulated after prolonged insulin infusion. As a first step toward confirming this mechanism and beginning to develop a therapeutic anti-IGF-1R monoclonal antibody (mAb) for horses, it was necessary to identify available human IGF-1R mAbs that would recognize equine receptors. Four IGF-1R mAbs were tested using soluble equine IGF-1R, with ELISA and flow cytometry. Frozen equine lamellar and liver tissue was also used in radioligand binding assays. The results demonstrated that only one of the mAbs tested (mAb1) was able to compete effectively with IGF-1 for binding to its receptors in equine lamellar tissue, with an IC50 of 5 to 159 ng/mL. None of the 4 mAbs were able to bind to equine hepatic InsR. This study has generated valuable structure-activity information and has identified a prototype anti-IGF-1R mAb suitable for further development.
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Affiliation(s)
- S Rahnama
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - N Vathsangam
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - R Spence
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - S T Anderson
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - M A de Laat
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - S Bailey
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - M N Sillence
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia.
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Interleukin-17A pathway target genes are upregulated in Equus caballus supporting limb laminitis. PLoS One 2020; 15:e0232920. [PMID: 33301461 PMCID: PMC7728170 DOI: 10.1371/journal.pone.0232920] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 11/24/2020] [Indexed: 01/29/2023] Open
Abstract
Supporting Limb Laminitis (SLL) is a painful and crippling secondary complication of orthopedic injuries and infections in horses, often resulting in euthanasia. SLL causes structural alterations and inflammation of the interdigitating layers of specialized epidermal and dermal tissues, the lamellae, which suspend the equine distal phalanx from the hoof capsule. Activation of the interleukin-17A (IL-17A)-dependent inflammatory pathway is an epidermal stress response that contributes to physiologic cutaneous wound healing as well as pathological skin conditions. As a first test of the hypothesis that hoof lamellae of horses diagnosed with SLL also respond to stress by activating the IL-17A pathway, the expression of IL-17A, IL-17 receptor subunit A and 11 IL-17A effector genes was measured by RT-PCR or qPCR. Lamellar tissue was isolated from Thoroughbreds euthanized due to naturally occurring SLL and in age and breed matched non-laminitic controls. By RT-PCR, the IL-17 Receptor A subunit was expressed in both non-laminitic and laminitic tissues, while IL-17A was primarily detectable in laminitic tissues. IL-17A target gene expression was undetectable in non-laminitic samples with the exception of weak detection of DEFB4B, S100A9 and PTSG2. In contrast, all target genes examined, except CCL20, were expressed by some or all laminitic samples. By qPCR, severe acute (n = 7) SLL expressed ~15–100 fold higher levels of DEFB4B and S100A9 genes compared to non-laminitic controls (n = 8). DEFB4B was also upregulated in developmental/subclinical (n = 8) and moderate acute (n = 7) by ~ 5-fold, and in severe chronic (n = 5) by ~15–200 fold. In situ hybridization (DEFB4) and immunofluorescence (calprotectin, a dimer of S100A9/S100A8 proteins) demonstrated expression in keratinocytes, primarily in suprabasal cell layers, from SLL samples. These data demonstrate upregulation of a cohort of IL-17A target genes in SLL and support the hypothesis that similarities in the response to stresses and damage exist between equine and human epidermal tissues.
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Carslake HB, Pinchbeck GL, McGowan CM. Equine metabolic syndrome in UK native ponies and cobs is highly prevalent with modifiable risk factors. Equine Vet J 2020; 53:923-934. [PMID: 33128277 PMCID: PMC8451835 DOI: 10.1111/evj.13378] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/22/2020] [Accepted: 10/22/2020] [Indexed: 12/29/2022]
Abstract
BACKGROUND The epidemiology of equine metabolic syndrome (EMS) is poorly described. OBJECTIVES To estimate the prevalence of EMS in native UK ponies and cobs in England and Wales and identify associated risk factors. STUDY DESIGN Cross-sectional study. METHODS Breeders registered with UK native pony breed societies and registered riding schools and livery yards within a set radius were invited to participate. All native UK ponies and cobs aged 3-14 years and not diagnosed or being treated for conditions likely to affect insulin regulation at participating premises were eligible. Animals underwent a clinical examination and an oral glucose test while their owner or keeper completed a questionnaire by face-to-face interview. Data were analysed by multilevel uni- and multivariable modelling using insulin concentration and EMS diagnosis as outcomes. RESULTS A total of 354 animals were examined at 64 properties (19 studs, 19 livery yards, 26 riding schools). The overall prevalence of EMS adjusted for clustering within yard was 23.3% (95%CI 17.9%-29.8%). Risk factors associated with a diagnosis of EMS included age, being female, more sedentary main activity, obesity, and shorter periods on pasture during the summer. Compared to the Welsh section A, the other Welsh, Connemara and cob breeds all had decreased odds of EMS. Clinical manifestations of hoof growth ring and supraorbital fat scores of 3/3 were more frequent in EMS ponies and animals with a history of laminitis within the last 5 years (9.7%) were 14.4 (95% CI 5.9-35.3) times more likely to be positive for EMS than those without. MAIN LIMITATIONS Results may not be transferable to other breeds or age groups. CONCLUSIONS Equine metabolic syndrome is highly prevalent in UK native ponies and cobs with modifiable risk factors including obesity and sedentary activities. Modifying risk factors could help reduce the risk of laminitis in susceptible animals.
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Affiliation(s)
- Harry B Carslake
- Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and Life Sciences, University of Liverpool, Leahurst, UK
| | - Gina L Pinchbeck
- Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and Life Sciences, University of Liverpool, Leahurst, UK
| | - Catherine M McGowan
- Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and Life Sciences, University of Liverpool, Leahurst, UK
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Galantino-Homer H, Brooks SA. Genetics and Signaling Pathways of Laminitis. Vet Clin North Am Equine Pract 2020; 36:379-394. [PMID: 32654786 DOI: 10.1016/j.cveq.2020.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Laminitis is a devastating disease with diverse etiologies and few, if any, effective treatments. Gene expression and hypothesis-generating genomic studies have provided a fresh look at the key molecular players at crucial timepoints in diverse experimental and naturally affected tissues. We summarize findings to date, and propose a unifying model of the laminitis disease process that includes several pathogenesis concepts shared with other diseases of epidermal and epithelial tissues. The value of these new pathways as potential therapeutic targets is exciting but will require careful future work to validate new methods and launch systematic clinical trials.
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Affiliation(s)
- Hannah Galantino-Homer
- Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA
| | - Samantha A Brooks
- Department of Animal Sciences, UF Genetics Institute, University of Florida, Gainesville, FL, USA.
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Campolo A, Frantz MW, de Laat MA, Hartson SD, Furr MO, Lacombe VA. Differential Proteomic Expression of Equine Cardiac and Lamellar Tissue During Insulin-Induced Laminitis. Front Vet Sci 2020; 7:308. [PMID: 32596266 PMCID: PMC7303262 DOI: 10.3389/fvets.2020.00308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 05/05/2020] [Indexed: 12/22/2022] Open
Abstract
Endocrinopathic laminitis is pathologically similar to the multi-organ dysfunction and peripheral neuropathy found in human patients with metabolic syndrome. Similarly, endocrinopathic laminitis has been shown to partially result from vascular dysfunction. However, despite extensive research, the pathogenesis of this disease is not well elucidated and laminitis remains without an effective treatment. Here, we sought to identify novel proteins and pathways underlying the development of equine endocrinopathic laminitis. Healthy Standardbred horses (n = 4/group) were either given an electrolyte infusion, or a 48-h euglycemic-hyperinsulinemic clamp. Cardiac and lamellar tissues were analyzed by mass spectrometry (FDR = 0.05). All hyperinsulinemic horses developed laminitis despite being previously healthy. We identified 514 and 709 unique proteins in the cardiac and lamellar proteomes, respectively. In the lamellar tissue, we identified 14 proteins for which their abundance was significantly increased and 13 proteins which were significantly decreased in the hyperinsulinemic group as compared to controls. These results were confirmed via real-time reverse-transcriptase PCR. A STRING analysis of protein-protein interactions revealed that these increased proteins were primarily involved in coagulation and complement cascades, platelet activity, and ribosomal function, while decreased proteins were involved in focal adhesions, spliceosomes, and cell-cell matrices. Novel significant differentially expressed proteins associated with hyperinsulinemia-induced laminitis include talin−1, vinculin, cadherin-13, fibrinogen, alpha-2-macroglobulin, and heat shock protein 90. In contrast, no proteins were found to be significantly differentially expressed in the heart of hyperinsulinemic horses compared to controls. Together, these data indicate that while hyperinsulinemia induced, in part, microvascular damage, complement activation, and ribosomal dysfunction in the lamellae, a similar effect was not seen in the heart. In brief, this proteomic investigation of a unique equine model of hyperinsulinemia identified novel proteins and signaling pathways, which may lead to the discovery of molecular biomarkers and/or therapeutic targets for endocrinopathic laminitis.
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Affiliation(s)
- Allison Campolo
- Department of Biochemistry and Molecular Biology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
| | - Matthew W Frantz
- Department of Biochemistry and Molecular Biology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
| | - Melody A de Laat
- Department of Biochemistry and Molecular Biology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States.,Biosciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Steven D Hartson
- Department of Biochemistry and Molecular Biology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
| | - Martin O Furr
- Department of Biochemistry and Molecular Biology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
| | - Véronique A Lacombe
- Department of Biochemistry and Molecular Biology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
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30
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Tivey ML, Van Dijk J, Dyson S. Extensive ossification of the ungular cartilages and other osseous abnormalities of the proximal and distal phalanges. EQUINE VET EDUC 2020. [DOI: 10.1111/eve.13165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- M.‐E. L. Tivey
- Centre for Equine Studies Animal Health Trust NewmarketSuffolkUK
| | - J. Van Dijk
- Centre for Preventative Medicine Animal Health Trust Newmarket Suffolk UK
| | - S. Dyson
- Centre for Equine Studies Animal Health Trust NewmarketSuffolkUK
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de Laat MA, Sillence MN. A review of recent developments in the pharmacological prevention and treatment of endocrinopathic laminitis. ANIMAL PRODUCTION SCIENCE 2020. [DOI: 10.1071/an19491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Despite the prevalence of endocrinopathic laminitis, the pharmacologic options for preventing and treating the disease are severely limited. The present review aims to discuss the spectrum of potential therapeutic agents for the condition, ranging from early experimental compounds to agents nearing registration. There are different pharmacologic targets for, and approaches to, managing laminitis. Reducing hyperinsulinaemia is central to diminishing endocrinopathic laminitis risk, and a detailed understanding of the pathophysiology of insulin dysregulation is necessary to identify pathways that can be targeted to minimise post-prandial insulin secretion and action. This area of research is advancing rapidly, with several exciting prospects, such as sodium-dependent glucose co-transporter-2 inhibitors, on the horizon for the treatment of equine metabolic dysfunction. Drugs that directly target the lamellae and aim to reduce the damage inflicted on the lamellae as part of this condition, are not yet available. Although progress in this area of laminitis therapy is slower, improved understanding of the events that lead to lamellar failure has enabled the investigation of novel drugs that aim to prevent laminitis at the site of the lesion. Finally, a brief review is included of the directions being taken in the management of the chronic and acute pain that accompanies laminitis. Medications for relieving the pain associated with laminitis are currently the most-prescribed drugs for the disease, and range from simple, affordable and thoroughly tested options, such as phenylbutazone, to newer, less-understood applications such as paracetamol and gabapentin. In the future, endocrinopathic laminitis management plans will likely take a multi-faceted approach that still hinge on effective dietary management and exercise, but also include drugs that address foot pathology, pain and underlying endocrine disturbances.
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de Laat MA, Spence RJ, Sillence MN, Pollitt CC. An investigation of the equine epidermal growth factor system during hyperinsulinemic laminitis. PLoS One 2019; 14:e0225843. [PMID: 31805097 PMCID: PMC6894753 DOI: 10.1371/journal.pone.0225843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 11/13/2019] [Indexed: 11/18/2022] Open
Abstract
Equine laminitis is a disease of the digital epidermal lamellae typified by epidermal cell proliferation and structural collapse. Most commonly the disease is caused by hyperinsulinemia, although the pathogenesis is incompletely understood. Insulin can activate the epidermal growth factor (EGF) system in other species and the present study tested the hypothesis that upregulation of EGF receptor (EGFR) signalling is a key factor in laminitis pathophysiology. First, we examined lamellar tissue from healthy Standardbred horses and those with induced hyperinsulinemia and laminitis for EGFR distribution and quantity using immunostaining and gene expression, respectively. Phosphorylation of EGFR was also quantified. Next, plasma EGF concentrations were compared in healthy and insulin-infused horses, and in healthy and insulin-dysregulated ponies before and after feeding. The EGFR were localised to the secondary epidermal lamellae, with stronger staining in parabasal, rather than basal, cells. No change in EGFR gene expression occurred with laminitis, although the receptor showed some phosphorylation. No difference was seen in EGF concentrations in horses, but in insulin-dysregulated ponies mean, post-prandial EGF concentrations were almost three times higher than in healthy ponies (274 ± 90 vs. 97.4 ± 20.9 pg/mL, P = 0.05). Although the EGFR does not appear to play a major pathogenic role in hyperinsulinemic laminitis, the significance of increased EGF in insulin-dysregulated ponies deserves further investigation.
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Affiliation(s)
- Melody A. de Laat
- Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- * E-mail:
| | - Robert J. Spence
- Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Martin N. Sillence
- Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Christopher C. Pollitt
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
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Magalhães J, Lima L, Paz C, Rocha Júnior S, Oliveira A, Duarte P, Alves G, Faleiros R. Relação espacial entre o estojo córneo e a falange distal em éguas Campolina adultas com e sem obesidade. ARQ BRAS MED VET ZOO 2019. [DOI: 10.1590/1678-4162-10702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
RESUMO A laminite endocrinopática tem acometido um número crescente de equinos com sinais de obesidade. Em um estudo recente com fêmeas jovens (até cinco anos) da raça Campolina, demonstraram-se indícios de alterações no dígito, ainda discretas, aparentemente associadas ao aumento da adiposidade. Com a hipótese de que essa associação é mais evidente em animais em faixa etária superior, o objetivo do presente estudo foi estudar éguas adultas (acima de cinco anos) da raça Campolina com e sem obesidade, avaliando-se radiograficamente a relação espacial entre estojo córneo e falange distal. Foram utilizadas 27 éguas entre seis e 14 anos de idade, sendo analisadas variáveis de adiposidade e medidas radiográficas dos cascos dos membros torácicos de equinos com escore corporal de 5 a 7/9 (grupo controle) e de 8 a 9 (grupo obeso). Foram feitas comparações entre os grupos e correlacionaram-se as variáveis de adiposidade com variáveis casco. A distância de afundamento da falange distal foi cerca de 20% superior nas éguas obesas (12,3±2,5 contra 10,2±2,2mm no grupo controle). Esse parâmetro também correlacionou (P<0,01) com vários parâmetros de adiposidade, com destaque para o escore de condição corporal (r=0,47) e a circunferência de pescoço a 75% (r=0,42). Os resultados corroboram estudos prévios que demonstraram associação entre obesidade e indícios de separação entre falange distal e estojo córneo em equinos de raças nacionais, comprovando, assim, a utilidade da avaliação radiográfica nesses animais. Em conclusão, éguas da raça Campolina com obesidade possuem alterações evidentes na relação espacial entre estojo córneo e falange distal, que se intensificam com o aumento da idade e da adiposidade.
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Affiliation(s)
| | - L.R. Lima
- Universidade Federal de Minas Gerais, Brazil
| | - C.F.R. Paz
- Universidade Federal de Minas Gerais, Brazil
| | | | | | - P.C. Duarte
- Universidade Federal de Minas Gerais, Brazil
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Yang Q, Lopez MJ. The Equine Hoof: Laminitis, Progenitor (Stem) Cells, and Therapy Development. Toxicol Pathol 2019; 49:1294-1307. [PMID: 31741428 DOI: 10.1177/0192623319880469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The equine hoof capsule, composed of modified epidermis and dermis, is vital for protecting the third phalanx from forces of locomotion. There are descriptions of laminitis, defined as inflammation of sensitive hoof tissues but recognized as pathologic changes with or without inflammatory mediators, in the earliest records of domesticated horses. Laminitis can range from mild to serious, and signs can be acute, chronic, or transition from acute, severe inflammation to permanently abnormal tissue. Damage within the intricate dermal and epidermal connections of the primary and secondary lamellae is often associated with lifelong changes in hoof growth, repair, and conformation. Decades of research contribute to contemporary standards of care that include systemic and local therapies as well as mechanical hoof support. Despite this, consistent mechanisms to restore healthy tissue formation following a laminitic insult are lacking. Endogenous and exogenous progenitor cell contributions to healthy tissue formation is established for most tissues. There is comparably little information about equine hoof progenitor cells. Equine hoof anatomy, laminitis, and progenitor cells are covered in this review. The potential of progenitor cells to advance in vitro equine hoof tissue models and translate to clinical therapies may significantly improve prevention and treatment of a devastating condition that has afflicted equine companions throughout history.
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Affiliation(s)
- Qingqiu Yang
- Department of Veterinary Clinical Sciences, Laboratory for Equine and Comparative Orthopedic Research, Baton Rouge, LA, USA
| | - Mandi J Lopez
- Department of Veterinary Clinical Sciences, Laboratory for Equine and Comparative Orthopedic Research, Baton Rouge, LA, USA
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35
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Armstrong C, Cassimeris L, Da Silva Santos C, Micoogullari Y, Wagner B, Babasyan S, Brooks S, Galantino-Homer H. The expression of equine keratins K42 and K124 is restricted to the hoof epidermal lamellae of Equus caballus. PLoS One 2019; 14:e0219234. [PMID: 31550264 PMCID: PMC6759161 DOI: 10.1371/journal.pone.0219234] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/11/2019] [Indexed: 01/30/2023] Open
Abstract
The equine hoof inner epithelium is folded into primary and secondary epidermal lamellae which increase the dermo-epidermal junction surface area of the hoof and can be affected by laminitis, a common disease of equids. Two keratin proteins (K), K42 and K124, are the most abundant keratins in the hoof lamellar tissue of Equus caballus. We hypothesize that these keratins are lamellar tissue-specific and could serve as differentiation- and disease-specific markers. Our objective was to characterize the expression of K42 and K124 in equine stratified epithelia and to generate monoclonal antibodies against K42 and K124. By RT-PCR analysis, keratin gene (KRT) KRT42 and KRT124 expression was present in lamellar tissue, but not cornea, haired skin, or hoof coronet. In situ hybridization studies showed that KRT124 localized to the suprabasal and, to a lesser extent, basal cells of the lamellae, was absent from haired skin and hoof coronet, and abruptly transitions from KRT124-negative coronet to KRT124-positive proximal lamellae. A monoclonal antibody generated against full-length recombinant equine K42 detected a lamellar keratin of the appropriate size, but also cross-reacted with other epidermal keratins. Three monoclonal antibodies generated against N- and C-terminal K124 peptides detected a band of the appropriate size in lamellar tissue and did not cross-react with proteins from haired skin, corneal limbus, hoof coronet, tongue, glabrous skin, oral mucosa, or chestnut on immunoblots. K124 localized to lamellar cells by indirect immunofluorescence. This is the first study to demonstrate the localization and expression of a hoof lamellar-specific keratin, K124, and to validate anti-K124 monoclonal antibodies.
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Affiliation(s)
- Caitlin Armstrong
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, Pennsylvania, United States of America
| | - Lynne Cassimeris
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Claire Da Silva Santos
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Yagmur Micoogullari
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Bettina Wagner
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Susanna Babasyan
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Samantha Brooks
- Department of Animal Sciences and University of Florida Genetics institute, University of Florida, Gainesville, Florida, United States of America
| | - Hannah Galantino-Homer
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, Pennsylvania, United States of America
- * E-mail:
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36
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Olley RB, Carslake HB, Ireland JL, McGowan CM. Comparison of fasted basal insulin with the combined glucose-insulin test in horses and ponies with suspected insulin dysregulation. Vet J 2019; 252:105351. [PMID: 31554591 DOI: 10.1016/j.tvjl.2019.105351] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 01/23/2023]
Abstract
Fasting horses for measurement of basal serum insulin concentration (fasting insulin; FI) has been recommended to standardise testing for insulin dysregulation (ID), yet limited data exist comparing it to dynamic tests. This study aimed to compare FI with the combined glucose-insulin test (CGIT) in horses suspect for ID. We hypothesised that FI would have poor sensitivity for detecting ID compared to CGIT using conventional cut-offs. Records were retrieved from CGITs performed in horses fasted for approximately 8h. Serum insulin and glucose concentrations were measured before and for 150min following an IV bolus of glucose followed by insulin. Correlations between FI and CGIT values were assessed. Youden's index analysis was used to determine the optimal cut-off for FI. Logistic regression and Mann-Whitney U tests were used to determine factors affecting the results. CGITs (n=130) from 62 horses were evaluated. Compared to CGIT, sensitivity and specificity of FI for diagnosis of ID were 14.6% and 100% at a cut-off of 20μIU/mL and 63.4% and 87.2% at a cut-off of 5.2μIU/mL, respectively. FI was significantly correlated with insulin at 45min (rs=0.66) and 75min (rs=0.72); area under the curve for insulin (AUCinsulin; rs=0.67); glucose at 45min (rs=0.53); and AUCglucose (rs=0.50). Obesity was significantly associated with increased odds of a positive CGIT and horses with a positive CGIT were significantly older (P<0.05). In conclusion, FI correlated well with CGIT results and had adequate sensitivity and specificity at lower cut-offs, despite poor sensitivity at conventional cut-off values. Further research to derive cut-off values relevant to the fasting period is warranted.
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Affiliation(s)
- R B Olley
- Institute of Veterinary Science, Faculty of Health and Life Sciences, University of Liverpool, Leahurst, Cheshire CH64 7TE, UK
| | - H B Carslake
- Institute of Veterinary Science, Faculty of Health and Life Sciences, University of Liverpool, Leahurst, Cheshire CH64 7TE, UK
| | - J L Ireland
- Institute of Veterinary Science, Faculty of Health and Life Sciences, University of Liverpool, Leahurst, Cheshire CH64 7TE, UK
| | - C M McGowan
- Institute of Veterinary Science, Faculty of Health and Life Sciences, University of Liverpool, Leahurst, Cheshire CH64 7TE, UK.
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Ragno VM, Zello GA, Klein CD, Montgomery JB. From Table to Stable: A Comparative Review of Selected Aspects of Human and Equine Metabolic Syndrome. J Equine Vet Sci 2019; 79:131-138. [PMID: 31405493 DOI: 10.1016/j.jevs.2019.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 06/06/2019] [Accepted: 06/08/2019] [Indexed: 12/18/2022]
Abstract
Obesity data in people and companion animals are depicting a future of increasing morbidity, cost for society, and significant health and welfare concerns. Between 25 and 50% of cats, dogs, and horses in developed countries are overweight or obese, which mirrors the situation in humans. Equine metabolic syndrome (EMS) was named after human metabolic syndrome (MetS), which has about 30 years of lead in research efforts. Even though the complications of the two syndromes seem to grossly differ (cardiac vs. laminitis risk), a number of similar disease mechanisms are worthy of investigation. Since the first EMS consensus statement by the American College of Veterinary Internal Medicine in 2010, numerous studies have confirmed the link between insulin dysregulation and laminitis, even though the mechanisms are not fully understood. After the discovery of the role of adipokines in MetS, evidence about inflammatory mechanisms related to adiposity in rodent models, companion animals, horses, and humans is constantly increasing. Oxidative and dicarbonyl stress have been correlated with insulin dysregulation, obesity, and recently with laminitis. Vascular actions of insulin through nitric oxide, endothelin-1, and other mechanisms are being studied in horses and can provide a better understanding of laminitis pathophysiology. More research is needed on neuropathic mechanisms in insulin-dysregulated horses, which could be important in the pathogenesis of laminitis and laminitic pain. Human literature can provide viable material for novel studies in areas that have received limited attention, in addition to being valuable information for clients about the consequences of unhealthy management of their horses.
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Affiliation(s)
- Valentina M Ragno
- Department of Large Animal Clinical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
| | - Gordon A Zello
- Section of Nutrition, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon SK S7N 5E5, Canada
| | - Colby D Klein
- Department of Large Animal Clinical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Julia B Montgomery
- Department of Large Animal Clinical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
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Meier A, de Laat M, Pollitt C, Walsh D, McGree J, Reiche DB, von Salis-Soglio M, Wells-Smith L, Mengeler U, Mesa Salas D, Droegemueller S, Sillence MN. A "modified Obel" method for the severity scoring of (endocrinopathic) equine laminitis. PeerJ 2019; 7:e7084. [PMID: 31211020 PMCID: PMC6557244 DOI: 10.7717/peerj.7084] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/06/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Laminitis is a common equine disease characterized by foot pain, and is commonly diagnosed using a five-grade Obel system developed in 1948 using sepsis-related cases. However, endocrinopathic laminitis is now the most common form of the disease and clinical signs may be mild, or spread across two Obel grades. This paper describes a modified method which assigns scores to discreet clinical signs, providing a wider scale suitable for use in a research setting. METHODS The "modified Obel" method was developed using an iterative process. First, a prototype method was developed during the detailed observation of 37 ponies undergoing a laminitis induction experiment. The final method was refined and validated using video footage taken during the induction study and from a clinical trial of naturally occurring endocrinopathic laminitis cases. The Obel method was deconstructed and key laminitis signs were evaluated to develop a three-stage, five criteria method that employs a severity scale of 0-12. Veterinarians (n = 28) were recruited to watch and assess 15 video recordings of cases of varying severity, using the Obel and "modified Obel" methods. The inter-observer agreement (reproducibility) was determined using Kendall's coefficient of concordance (Kendall W) and Krippendorf's alpha reliability coefficient. A total of 14 veterinarians repeated the exercise 2-4 weeks after their original assessment, to determine intra-observer agreement (repeatability), assessed using a weighted kappa statistic (kw). Agreement between methods was calculated by converting all "modified Obel" scores to Obel grades and calculating the mean and distribution of the differences. RESULTS The "modified Obel" and Obel methods showed excellent and similar inter-observer agreement based on the Kendall W value (0.87, P < 0.001 vs. 0.85, P < 0.001) and Krippendorf's alpha (95% CI) value (0.83 [0.53-0.90] vs. 0.77 [0.55-0.85]). Based on the kw value, the "modified Obel" method also had substantial repeatability, although slightly less than the Obel method, (0.80 vs. 0.91). Excellent agreement between the methods was found, with the mean difference (95% CI), comparing the Obel grade, with the "modified Obel" score converted to an Obel grade, being -0.12 (-0.19 to -0.06) grades. The Obel and converted "modified Obel" grades were identical 62% of the time (259/420) and a difference of one grade (higher or lower) occurred in 35% of cases (148/420). CONCLUSION Both methods show excellent agreement, reproducibility and repeatability when used to diagnose endocrinopathic laminitis. The "modified Obel" method is a three-step examination process for severity-scoring of endocrinopathic laminitis, initially proposed for use within a research setting. When using the modified method a diagnosis of laminitis also requires clinical acumen. The allocation of scores for specific clinical signs should be particularly useful in research trials monitoring laminitis recovery.
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Affiliation(s)
- Alexandra Meier
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Brisbane, QLD, Australia
| | - Melody de Laat
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Brisbane, QLD, Australia
| | - Christopher Pollitt
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia
| | | | - James McGree
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | | | | | | | | | | | | | - Martin N. Sillence
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Brisbane, QLD, Australia
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Are There Shared Mechanisms in the Pathophysiology of Different Clinical Forms of Laminitis and What Are the Implications for Prevention and Treatment? Vet Clin North Am Equine Pract 2019; 35:379-398. [PMID: 31126692 DOI: 10.1016/j.cveq.2019.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Laminitis is a consequence of primary disease processes elsewhere in the body. The key pathophysiologic events are insulin dysregulation in endocrinopathic laminitis, ischemia in supporting limb laminitis, and inflammation in sepsis-related laminitis. These apparently disparate mechanisms converge to cause lamellar attachment failure through epithelial cell adhesion loss and stretch, possibly mediated by common growth factor signaling pathways. Tissue damage through mechanical distraction, inflammation, pain, and a proliferative epithelial healing response are features of acute laminitis regardless of the cause. Preventive and treatment strategies based on knowledge of these unique and common mechanistic events are likely to improve clinical outcomes.
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de Laat MA, Reiche DB, Sillence MN, McGree JM. Incidence and risk factors for recurrence of endocrinopathic laminitis in horses. J Vet Intern Med 2019; 33:1473-1482. [PMID: 30972832 PMCID: PMC6524073 DOI: 10.1111/jvim.15497] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/29/2019] [Indexed: 12/27/2022] Open
Abstract
Background Endocrinopathic laminitis is common in horses and ponies, but the recurrence rate of the disease is poorly defined. Objectives To determine the incidence of, and risk factors for, the recurrence of endocrinopathic laminitis. Animals Privately owned horses and ponies with acute laminitis (n = 317, of which 276 cases with endocrinopathic laminitis were followed up to study completion). Methods This prospective cohort study collected data on veterinary‐diagnosed cases of acute laminitis for 2 years. Each case was classified on acceptance to the study as endocrinopathic or non‐endocrinopathic using data collected in a questionnaire completed by the animal's veterinarian. Follow‐up data were collected at regular intervals to determine whether the laminitis recurred in the 2‐year period after diagnosis. Results The recurrence rate for endocrinopathic laminitis was 34.1%. The risk of recurrence during the 2‐year study period increased with basal, fasted serum insulin concentration (P ≤ .05), with the probability of recurrence increasing markedly as the insulin concentration increased beyond the normal range (0‐20 μIU/mL) to over the threshold for normal (up to approximately 45 μIU/mL). Being previously diagnosed with laminitis (before the study; P = .05) was also a risk factor for recurrent laminitis. Cases with a higher Obel grade of laminitis were likely (P = .05) to recur sooner. Conclusions and clinical importance Knowing that hyperinsulinemia and being previously diagnosed with laminitis are significant risk factors for recurrence will enable clinicians to proactively address these factors, thereby potentially reducing the risk of recurrence of laminitis.
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Affiliation(s)
- Melody A de Laat
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Dania B Reiche
- Animal Health, Boehringer Ingelheim Vetmedica GmbH, Ingelheim am Rhein, Germany
| | - Martin N Sillence
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
| | - James M McGree
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
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Watts MR, Hegedus OC, Eades SC, Belknap JK, Burns TA. Association of sustained supraphysiologic hyperinsulinemia and inflammatory signaling within the digital lamellae in light-breed horses. J Vet Intern Med 2019; 33:1483-1492. [PMID: 30912229 PMCID: PMC6524466 DOI: 10.1111/jvim.15480] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 03/05/2019] [Indexed: 12/24/2022] Open
Abstract
Background Hyperinsulinemia is associated with equine laminitis, and digital lamellar inflammation in equine metabolic syndrome‐associated laminitis (EMSAL) is modest when compared with sepsis‐associated laminitis. Objectives To characterize digital lamellar inflammation in horses in a euglycemic‐hyperinsulinemic clamp (EHC) model of laminitis. Animals Sixteen healthy adult Standardbred horses. Methods Prospective experimental study. Horses underwent EHC or saline infusion (CON) for 48 hours or until the onset of Obel grade 1 laminitis. Horses were euthanized, and digital lamellar tissue was collected and analyzed via polymerase chain reaction (pro‐inflammatory cytokine and chemokine genes—CXCL1, CXCL6, CXCL8, IL‐6, MCP‐1, MCP‐2, IL‐1β, IL11, cyclooxygenases 1 and 2, tumor necrosis factor alpha [TNF‐α], E‐selectin, and ICAM‐1), immunoblotting (phosphorylated and total signal transducer and activator of transcription 1 [STAT1], STAT3, and p38MAPK), and immunohistochemistry (markers of leukocyte infiltration: CD163, MAC387). Results Lamellar mRNA concentrations of IL‐1β, IL‐6, IL‐11, COX‐2, and E‐selectin were increased; the concentration of COX‐1 was decreased; and concentrations of CXCL1, CXCL6, MCP‐1, MCP‐2, IL‐8, TNF‐α and ICAM‐1 were not significantly different in the EHC group compared to the CON group (P ≤ .003). Lamellar concentrations of phosphorylated STAT proteins (P‐STAT1 [S727], P‐STAT1 [Y701], P‐STAT3 [S727], and P‐STAT3 [Y705]) were increased in the EHC group compared to the CON group, with phosphorylated STAT3 localizing to nuclei of lamellar basal epithelial cells. There was no change in the lamellar concentration of P‐p38 MAPK (T180/Y182), but the concentration of total p38 MAPK was decreased in the EHC samples. There was no evidence of notable lamellar leukocyte emigration. Conclusions and Clinical Importance These results establish a role for lamellar inflammatory signaling under conditions associated with EMSAL.
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Affiliation(s)
- Mauria R Watts
- Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, Ohio
| | - Olivia C Hegedus
- Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, Ohio
| | - Susan C Eades
- Department of Large Animal Clinical Sciences, Texas A&M University College of Veterinary Medicine and Biomedical Sciences, College Station, Texas
| | - James K Belknap
- Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, Ohio
| | - Teresa A Burns
- Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, Ohio
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42
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Pollard D, Wylie CE, Verheyen KLP, Newton JR. Identification of modifiable factors associated with owner-reported equine laminitis in Britain using a web-based cohort study approach. BMC Vet Res 2019; 15:59. [PMID: 30755193 PMCID: PMC6373032 DOI: 10.1186/s12917-019-1798-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 01/25/2019] [Indexed: 12/27/2022] Open
Abstract
Background Equine laminitis is a complex disease that manifests as pain and lameness in the feet, often with debilitating consequences. There is a paucity of data that accounts for the multifactorial nature of laminitis and considers time-varying covariates that may be associated with disease development; particularly those that are modifiable and present potential interventions. A previous case-control study identified a number of novel, modifiable factors associated with laminitis which warranted further investigation and corroboration. The aim of this study was to identify factors associated with equine laminitis in horses/ponies in Great Britain (GB) using a prospective, web-based cohort study design, with particular interest in evaluating modifiable factors previously identified in the case-control study. Results Self-selected horse/pony owners in GB submitted initial baseline and follow-up health and management questionnaires for 1070 horses/ponies between August 2014 and December 2016. The enrolled horses/ponies contributed 1068 horse-years at risk with a median of 38 days between questionnaire submissions. Owners reported 123 owner-recognised and/or veterinary-diagnosed episodes of active laminitis using a previously-validated laminitis reporting form. Multivariable Cox regression modelling identified 16 risk/protective factors associated with laminitis development. In keeping with the previous case-control study, a prior history of laminitis (particularly non-veterinary-diagnosed episodes), soreness after shoeing/trimming and weight gain were associated with higher rates of laminitis. There is now strong evidence that these risk factors should be used to guide future recommendations in disease prevention. Factors with some prior evidence of association included breed, steroidal anti-inflammatory administration, transport and worming. The modifiable factors amongst these should be the focus of future laminitis studies. The remainder of the identified factors relating to health, turnout and grazing management and feeding are novel, and require further investigation to explore their relationship with laminitis and their applicability as potential interventions. Conclusions This study has demonstrated a temporal relationship between a number of horse- and management-level factors and laminitis, identifying potential interventions and important risk groups for which these interventions would be of particular importance. These results serve as a sound evidence-base towards the development of strategic recommendations for the horse/pony-owning population to reduce the rate of laminitis in GB. Electronic supplementary material The online version of this article (10.1186/s12917-019-1798-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- D Pollard
- Epidemiology Department, Centre for Preventive Medicine, Animal Health Trust, Newmarket, Suffolk, UK. .,Veterinary Epidemiology, Economics and Public Health Group, Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, Hertfordshire, UK.
| | - C E Wylie
- Rossdales Equine Hospital, Exning, Newmarket, UK.,University of Sydney, School of Medical Sciences, Camperdown, Sydney, Australia
| | - K L P Verheyen
- Veterinary Epidemiology, Economics and Public Health Group, Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, Hertfordshire, UK
| | - J R Newton
- Epidemiology Department, Centre for Preventive Medicine, Animal Health Trust, Newmarket, Suffolk, UK
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43
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Stokes SM, Belknap JK, Engiles JB, Stefanovski D, Bertin FR, Medina-Torres CE, Horn R, van Eps AW. Continuous digital hypothermia prevents lamellar failure in the euglycaemic hyperinsulinaemic clamp model of equine laminitis. Equine Vet J 2019; 51:658-664. [PMID: 30636340 DOI: 10.1111/evj.13072] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/01/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND Continuous digital hypothermia can prevent the development and progression of laminitis associated with sepsis but its effects on laminitis due to hyperinsulinaemia are unknown. OBJECTIVES To determine the effects of continuous digital hypothermia on laminitis development in the euglycaemic hyperinsulinaemic clamp model. STUDY DESIGN Randomised, controlled (within subject), blinded, experiment. METHODS Eight clinically normal Standardbred horses underwent laminitis induction using the euglycaemic hyperinsulinaemic clamp model (EHC). At initiation of the EHC, one forelimb was continuously cooled (ICE), with the other maintained at ambient temperature (AMB). Dorsal lamellar sections (proximal, middle, distal) were harvested 48 h after initiation of the EHC and were analysed using histological scoring (0-3) and histomorphometry. Cellular proliferation was quantified by counting epidermal cell nuclei staining positive with an immunohistochemical proliferation marker (TPX2). RESULTS Severe elongation and disruption of SEL with dermo-epidermal separation (score of 3) was observed in all AMB feet at one or more section locations, but was not observed in any ICE sections. Overall 92% of the AMB sections received the most severe histological score (grade 3) and 8% were grade 2, whereas ICE sections were classified as either grade 1 (50%) or grade 2 (50%). Relative to AMB feet, ICE sections were 98% less likely to exhibit grades 2 or 3 (OR: 0.02, 95% CI 0.001, 0.365; P<0.01). Histomorphometry measurements of total and nonkeratinised primary epidermal lamellar length were significantly increased (P<0.01) in AMB limbs compared with ICE. TPX2 positive cell counts were significantly increased (P<0.01) in AMB limbs compared with ICE. MAIN LIMITATIONS Continuous digital hypothermia was initiated before recognition of laminitis and therefore the clinical applicability requires further investigation. CONCLUSIONS Continuous digital hypothermia reduced the severity of laminitis in the EHC model and prevented histological lesions compatible with lamellar structural failure.
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Affiliation(s)
- S M Stokes
- Australian Equine Laminitis Research Unit, School of Veterinary Science, the University of Queensland, Gatton, Queensland, Australia
| | - J K Belknap
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, the Ohio State University, Columbus, Ohio, USA
| | - J B Engiles
- New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA.,New Bolton Center, Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - D Stefanovski
- New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - F R Bertin
- Australian Equine Laminitis Research Unit, School of Veterinary Science, the University of Queensland, Gatton, Queensland, Australia
| | - C E Medina-Torres
- Australian Equine Laminitis Research Unit, School of Veterinary Science, the University of Queensland, Gatton, Queensland, Australia
| | - R Horn
- Australian Equine Laminitis Research Unit, School of Veterinary Science, the University of Queensland, Gatton, Queensland, Australia
| | - A W van Eps
- Australian Equine Laminitis Research Unit, School of Veterinary Science, the University of Queensland, Gatton, Queensland, Australia.,New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA
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Durham AE, Frank N, McGowan CM, Menzies-Gow NJ, Roelfsema E, Vervuert I, Feige K, Fey K. ECEIM consensus statement on equine metabolic syndrome. J Vet Intern Med 2019; 33:335-349. [PMID: 30724412 PMCID: PMC6430910 DOI: 10.1111/jvim.15423] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/11/2019] [Indexed: 12/26/2022] Open
Abstract
Equine metabolic syndrome (EMS) is a widely recognized collection of risk factors for endocrinopathic laminitis. The most important of these risk factors is insulin dysregulation (ID). Clinicians and horse owners must recognize the presence of these risk factors so that they can be targeted and controlled to reduce the risk of laminitis attacks. Diagnosis of EMS is based partly on the horse's history and clinical examination findings, and partly on laboratory testing. Several choices of test exist which examine different facets of ID and other related metabolic disturbances. EMS is controlled mainly by dietary strategies and exercise programs that aim to improve insulin regulation and decrease obesity where present. In some cases, pharmacologic aids might be useful. Management of an EMS case is a long‐term strategy requiring diligence and discipline by the horse's carer and support and guidance from their veterinarians.
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Affiliation(s)
| | - Nicholas Frank
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts
| | - Cathy M McGowan
- Institute of Veterinary Science, University of Liverpool, Neston, United Kingdom
| | - Nicola J Menzies-Gow
- Department of clinical sciences and services, Royal Veterinary College, Herts, United Kingdom
| | - Ellen Roelfsema
- Department of Equine Sciences, Utrecht University, Utrecht, The Netherlands
| | - Ingrid Vervuert
- Faculty of Veterinary Medicine, University of Leipzig, Institute of Animal Nutrition, Nutrition Diseases and Dietetics, Leipzig, Germany
| | - Karsten Feige
- Clinic for Horses, University of Veterinary Medicine Hannover, Germany
| | - Kerstin Fey
- Equine Clinic, Internal Medicine, Faculty of Veterinary Medicine, Justus-Liebig-University of Giessen, Giessen, Germany
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Laat MA. Science in brief: Progress in endocrinopathic laminitis research: Have we got a foothold? Equine Vet J 2019; 51:141-142. [DOI: 10.1111/evj.13056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 12/21/2022]
Affiliation(s)
- M. A. Laat
- Science and Engineering Faculty Queensland University of Technology Brisbane Australia
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46
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Cassimeris L, Engiles JB, Galantino-Homer H. Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis. BMC Vet Res 2019; 15:24. [PMID: 30630474 PMCID: PMC6327420 DOI: 10.1186/s12917-018-1748-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 12/14/2018] [Indexed: 12/15/2022] Open
Abstract
Background Laminitis is often associated with endocrinopathies that cause hyperinsulinemia and is also induced experimentally by hyperinsulinemia, suggesting that insulin initiates laminitis pathogenesis. Hyperinsulinemia is expected to activate pro-growth and anabolic signaling pathways. We hypothesize that chronic over-stimulation of these pathways in lamellar tissue results in endoplasmic reticulum stress, contributing to tissue pathology, as it does in human metabolic diseases. We tested this hypothesis by asking whether lamellar tissue from horses with naturally-occurring endocrinopathic laminitis showed expression of protein markers of endoplasmic reticulum stress. Results Three markers of endoplasmic reticulum stress, spliced XBP1, Grp78/BiP and Grp94, were upregulated 2.5–9.5 fold in lamellar tissues of moderately to severely laminitic front limbs (n = 12) compared to levels in controls (n = 6–7) measured by immunoblotting and densitometry. Comparing expression levels between laminitic front limbs and less affected hind limbs from the same horses (paired samples from 7 to 8 individual horses) demonstrated significantly higher expression for both spliced XBP1 and Grp78/BiP in the laminitic front limbs, and a similar trend for Grp94. Expression levels of the 3 markers were minimal in all samples of the control (n = 6–7) or hind limb groups (n = 7–8). Immunofluorescent localizations were used to identify cell types expressing high levels of Grp78/BiP, as an indicator of endoplasmic reticulum stress. Grp78/BiP expression was highly elevated in suprabasal epidermal keratinocytes and only observed in laminitic front limbs (10/12 laminitic samples, compared to 0/7 in sections from the hind limbs and 0/5 of controls). Conclusions These data demonstrate that the endoplasmic reticulum stress pathway is active in naturally occurring cases of laminitis and is most active within a subset of epidermal keratinocytes. These data provide the rationale for further study of endoplasmic reticulum stress in experimental models of laminitis and the links between laminitis and human diseases sharing activation of this stress pathway. Pharmacological options to manipulate the endoplasmic reticulum stress pathway under investigation for human disease could be applicable to laminitis treatment and prevention should this pathway prove to be a driver of disease progression. Electronic supplementary material The online version of this article (10.1186/s12917-018-1748-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lynne Cassimeris
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA.
| | - Julie B Engiles
- Department of Clinical Studies/New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, 19348, USA.,Department of Pathobiology/New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hannah Galantino-Homer
- Department of Clinical Studies/New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, 19348, USA
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Nanayakkara SN, Rahnama S, Harris PA, Anderson ST, de Laat MA, Bailey S, Sillence MN. Characterization of insulin and IGF-1 receptor binding in equine liver and lamellar tissue: implications for endocrinopathic laminitis. Domest Anim Endocrinol 2019; 66:21-26. [PMID: 30205269 DOI: 10.1016/j.domaniend.2018.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 01/19/2023]
Abstract
Although it is well established that equine laminitis can be triggered by extreme hyperinsulinemia, the mechanism of insulin action is not known. High concentrations of insulin lead to separation of the weight-bearing apparatus from the hoof wall and are associated with an increased cycle of cell death and proliferation in the lamellae. Gene expression and immunohistochemistry studies have indicated that the lamellae are sparsely populated with insulin receptors, whereas IGF-1 receptors (IGF-1R) are abundant, suggesting that the action of insulin may be mediated by insulin binding to the IGF-1R. To investigate this possibility, cell membrane fragments containing IGF-1R were extracted from the livers of 6 horses and the lamellae of >50 horses euthanized for nonresearch purposes at an abattoir. Radioligand-binding studies using 125I-IGF-1 and 125I-insulin confirmed an abundance of high-affinity IGF-1R in the liver (KD 0.11 nM, Bmax 223 fmol/mg protein) and lamellae (KD 0.16 nM, Bmax 243 fmol/mg protein). However, the affinity of insulin for binding to the lamellar IGF-1R (Ki 934 nM) was >5,800 fold less than that of IGF-1, suggesting that insulin is unlikely to bind to equine IGF-1R at physiological concentrations. Although insulin receptors could be detected in the liver (KD 0.48 nM, Bmax 123 fmol/mg protein), they were barely detectable in lamellae (estimated Bmax 14 fmol/mg protein). There was no evidence to support the presence of insulin/IGF-1 hybrid receptors in either tissue. These findings suggest that insulin does not act directly through IGF-1 receptors and that an alternative theory is required to explain the mechanism of insulin action in laminitis.
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Affiliation(s)
- S N Nanayakkara
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Brisbane, Queensland, Australia
| | - S Rahnama
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Brisbane, Queensland, Australia
| | - P A Harris
- Equine Studies Group, WALTHAM Centre for Pet Nutrition, Waltham-on-the-Wolds, UK
| | - S T Anderson
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - M A de Laat
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Brisbane, Queensland, Australia
| | - S Bailey
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - M N Sillence
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Brisbane, Queensland, Australia.
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Baskerville CL, Chockalingham S, Harris PA, Bailey SR. The effect of insulin on equine lamellar basal epithelial cells mediated by the insulin-like growth factor-1 receptor. PeerJ 2018; 6:e5945. [PMID: 30519508 PMCID: PMC6275117 DOI: 10.7717/peerj.5945] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/16/2018] [Indexed: 12/26/2022] Open
Abstract
Background In horses and ponies, insulin dysregulation leading to hyperinsulinemia may be associated with increased risk of laminitis, and prolonged infusion of insulin can induce the condition. It is unclear whether insulin may have a direct or indirect effect on the lamellar tissues. Insulin is structurally related to insulin-like growth factor (IGF-1), and can bind the IGF-1 receptor, albeit at a lower affinity than IGF-1. Methods Immunohistochemistry was performed on formalin-fixed lamellar tissue sections from six normal horses, euthanised for non-research purposes, using an anti-IGF-1 receptor antibody. In further studies, lamellar epithelial cells were obtained by collagenase digestion from the hooves of 18 normal horses, also euthanised for non-research purposes, and incubated for 48 h in the presence of insulin (0–2,000 m IU/ml). The increase in cell numbers was determined using a cell proliferation assay, and compared to the effect of zero insulin using one-way ANOVA. Results Immunohistochemistry demonstrated IGF-1 receptors on lamellar epidermal epithelial cells. With cultured cells, insulin caused a concentration-dependent increase in cell proliferation compared to untreated cells (maximal effect 63.3 ± 12.8% more cells after 48 h with 1,000 m IU/ml insulin; P < 0.01). Co-incubation with a blocking antibody against the IGF-1 receptor significantly inhibited the proliferative effect of insulin (P < 0.01). Discussion These results demonstrate that IGF-1 receptors are present on lamellar epithelial cells. At high physiological concentrations, insulin may activate these cells, by a mechanism involving IGF-1 receptors, resulting in a proliferative effect. This mechanism could help to explain the link between hyperinsulinemia and laminitis.
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Affiliation(s)
- Courtnay L Baskerville
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Subu Chockalingham
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Patricia A Harris
- Equine Studies Group, WALTHAM Centre for Pet Nutrition, Melton Mowbray, Leicestershire, UK
| | - Simon R Bailey
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, VIC, Australia
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Mullard J, Ireland J, Dyson S. Radiographic assessment of the ratio of the hoof wall distal phalanx distance to palmar length of the distal phalanx in 415 front feet of 279 horses. EQUINE VET EDUC 2018. [DOI: 10.1111/eve.13004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- J. Mullard
- Centre for Equine Studies Animal Health Trust Suffolk UK
| | - J. Ireland
- Centre for Preventive Medicine Animal Health Trust Suffolk UK
| | - S. Dyson
- Centre for Equine Studies Animal Health Trust Suffolk UK
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The sodium-glucose co-transporter 2 inhibitor velagliflozin reduces hyperinsulinemia and prevents laminitis in insulin-dysregulated ponies. PLoS One 2018; 13:e0203655. [PMID: 30212530 PMCID: PMC6136744 DOI: 10.1371/journal.pone.0203655] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 08/26/2018] [Indexed: 11/19/2022] Open
Abstract
There are no registered veterinary drugs for treating insulin dysregulation and preventing insulin-associated laminitis in horses. Velagliflozin is a sodium-glucose co-transport 2 inhibitor that reduces renal glucose reabsorption, promotes glucosuria, and consequently, decreases blood glucose and insulin concentrations. This study aimed to determine if velagliflozin reduced hyperinsulinemia and prevented laminitis in insulin-dysregulated ponies fed a challenge diet high in non-structural carbohydrates (NSC). An oral glucose test (1 g dextrose/kg BW) was used to screen 75 ponies for insulin dysregulation, of which 49 ponies with the highest insulin concentrations were selected. These animals were assigned randomly to either a treated group (n = 12) that received velagliflozin (0.3 mg/kg BW, p.o., s.i.d.) throughout the study, or a control group (n = 37). All ponies were fed a maintenance diet of alfalfa hay for 3 weeks, before transferring to a challenge diet (12 g NSC/kg BW/d) for up to 18 d. Blood glucose and serum insulin concentrations were measured over 4 h after feeding, on d 2 of the diet. The maximum glucose concentration was 22% lower (P = 0.014) in treated animals, with a geometric mean (95% CI) of 9.4 (8.0–11.0) mM, versus 12.1 (10.7–13.7) mM in the controls. This was reflected by lower (45%) maximum insulin concentrations in the treated group (P = 0.017), of 149 (97–228) μIU/mL, versus 272 (207–356) μIU/mL for controls. The diet induced Obel grade 1 or 2 laminitis in 14 of the 37 controls (38%), whereas no velagliflozin-treated pony developed laminitis (P = 0.011). Velagliflozin was well-tolerated, with no hypoglycemia or any clinical signs of adverse effects. The main limitation of this study was the sample size. Velagliflozin shows promise as a safe and effective compound for treating insulin dysregulation and preventing laminitis by reducing the hyperinsulinemic response to dietary NSC.
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