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Menzies-Gow NJ, Knowles EJ. Sodium-glucose transport protein 2 inhibitor use in the management of insulin dysregulation in ponies and horses. J Vet Pharmacol Ther 2024. [PMID: 38984777 DOI: 10.1111/jvp.13470] [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: 03/01/2024] [Revised: 05/28/2024] [Accepted: 06/26/2024] [Indexed: 07/11/2024]
Abstract
Laminitis is a common and painful condition of the equine foot and approximately 90% of cases are associated with insulin dysregulation (ID) that is a central feature of the common endocrine disorder equine metabolic syndrome (EMS) and occurs in a subset of animals with pituitary pars intermedia dysfunction. Additional features of EMS include obesity, altered circulating concentrations of adipokines (particularly adiponectin and leptin) and hypertriglyceridaemia. Obesity, ID, hypoadiponectinaemia, hyperleptinaemia and an altered plasma lipid profile are also features of human metabolic syndrome (HMS) alongside hyperglycaemia. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a novel class of oral hypoglycaemic agents used in combination with lifestyle changes in the management of HMS. SGLT2 receptors are responsible for 90% of the renal glucose reabsorption that occurs in the proximal convoluted tubule. Thus, these drugs increase urinary glucose excretion by suppressing glucose reabsorption from the glomerular filtrate resulting in urinary calorie loss with consequent weight loss and improvements in ID, hyperglycemia, hypoadiponectinaemia and hyperleptinaemia. There are no licenced veterinary drugs available for treating ID and preventing insulin-associated laminitis in horses. Thus, the use of SGLT2i for the control of equine hyperinsulinaemia with the goal of improving recovery from associated active laminitis or preventing future laminitis has recently been advocated. There are a small number of published studies reporting the use of the SGLT2i canagliflozin, ertugliflozin and velagliflozin to aid the management of equine ID. However, the doses used are largely extrapolated from human studies with limited consideration of species-specific variations. In addition, there is limited evaluation of the fundamental differences between ID in horses and humans, particularly the fact that most horses with ID remain hyperinsulinaemic but normoglycaemic such that increased urinary loss of glucose may not explain the beneficial effects of these drugs. Further study of the potential deleterious effects of treatment-associated hypertriglyceridaemia is required together with the effect of SGLT2i therapy on circulating concentrations of adipokines in horses.
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Affiliation(s)
- Nicola J Menzies-Gow
- Department of Clinical Science and Services, Royal Veterinary College, Hertfordshire, UK
| | - Edward J Knowles
- Department of Clinical Science and Services, Royal Veterinary College, Hertfordshire, UK
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Horner A, Bamford NJ, Stear MJ, Piedrafita D, Jabbar A, Hughes KJ, El-Hage CM, Preston S. Strongyle egg shedding and egg reappearance periods in horses with pituitary pars intermedia dysfunction. Vet Parasitol 2024; 328:110176. [PMID: 38603926 DOI: 10.1016/j.vetpar.2024.110176] [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: 12/11/2023] [Revised: 03/26/2024] [Accepted: 03/26/2024] [Indexed: 04/13/2024]
Abstract
Pituitary pars intermedia dysfunction (PPID) is the most common endocrine disorder of older horses. Immune dysfunction in horses with PPID could increase susceptibility to infectious diseases, including strongyle infections; however, few data are available. The aim of this study was to determine if horses with PPID had increased strongyle faecal egg counts (FEC) compared with control horses, over a fourteen-week period in Victoria, Australia. Clinical signs and plasma adrenocorticotropic hormone (ACTH) concentrations were used to categorise horses into PPID (n=14) or control (n=31) groups. Faecal samples were collected for FEC determination prior to anthelmintic treatment, and fortnightly post-treatment for each horse. Generalised linear mixed modelling, using a gamma distribution, was used to compare differences between groups in the repeated measures study. The confounding variable of age was controlled for as a fixed effect. Following anthelmintic treatment, mean FEC was greater for the PPID group compared to the control group on day 56 (405 ± 756 eggs per gram [EPG] vs 40 ± 85 EPG, p=0.05) and day 70 (753 ±1598 EPG vs 82 ±141 EPG, p=0.04). There were no differences in mean FEC between groups on days 84 and 98. Cumulative FEC (day 14 to day 98) was significantly greater for the PPID horses than control horses (2118 ± 4016 EPG vs 798 ± 768 EPG, p<0.0001). Group egg reappearance period was shorter for PPID horses (day 56 post-anthelmintic treatment) compared to control horses (day 70) and 30% of the PPID horses reached a FEC threshold of >200 EPG on day 42, compared to 0% of control horses (p=0.02). These results suggest that the rate of a re-established patent infection between groups could be different due to a comprised immune response in PPID horses or differences in the host-parasite relationship regarding encysted stage larvae. However, despite differences between groups, some horses with PPID consistently had no detectable or low FEC (<200 EPG) during the study period. These findings highlight the importance of individual FEC monitoring to determine if anthelmintic treatment is required, in line with sustainable parasite management practices.
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Affiliation(s)
- Adelaina Horner
- Institute of Innovation, Science and Sustainability, Federation University, Victoria 3350, Australia
| | - Nicholas J Bamford
- Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michael J Stear
- School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - David Piedrafita
- Institute of Innovation, Science and Sustainability, Federation University, Victoria 3350, Australia
| | - Abdul Jabbar
- Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Kristopher J Hughes
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Charles M El-Hage
- Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Sarah Preston
- Institute of Innovation, Science and Sustainability, Federation University, Victoria 3350, Australia.
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Menzies-Gow NJ, Banse HE, Duff A, Hart N, Ireland JL, Knowles EJ, McFarlane D, Rendle D. BEVA primary care clinical guidelines: Diagnosis and management of equine pituitary pars intermedia dysfunction. Equine Vet J 2024; 56:220-242. [PMID: 37795557 DOI: 10.1111/evj.14009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/19/2023] [Indexed: 10/06/2023]
Abstract
BACKGROUND Pituitary pars intermedia dysfunction (PPID) is a prevalent, age-related chronic disorder in equids. Diagnosis of PPID can be challenging because of its broad spectrum of clinical presentations and disparate published diagnostic criteria, and there are limited available treatment options. OBJECTIVES To develop evidence-based primary care guidelines for the diagnosis and treatment of equine PPID based on the available literature. STUDY DESIGN Evidence-based clinical guideline using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework. METHODS Research questions were proposed by a panel of veterinarians and developed into PICO or another structured format. VetSRev and Veterinary Evidence were searched for evidence summaries, and systematic searches of the NCBI PubMed and CAB Direct databases were conducted using keyword searches in July 2022 and updated in January 2023. The evidence was evaluated using the GRADE framework. RESULTS AND RECOMMENDATIONS The research questions were categorised into four areas: (A) Case selection for diagnostic testing, pre-test probability and diagnostic test accuracy, (B) interpretation of test results, (C) pharmacological treatments and other treatment/management options and (D) monitoring treated cases. Relevant veterinary publications were identified and assessed using the GRADE criteria. The results were developed into recommendations: (A) Case selection for diagnostic testing and diagnostic test accuracy: (i) The prevalence of PPID in equids aged ≥15 years is between 21% and 27%; (ii) hypertrichosis or delayed/incomplete hair coat shedding provides a high index of clinical suspicion for PPID; (iii) the combination of clinical signs and age informs the index of clinical suspicion prior to diagnostic testing; (iv) estimated pre-test probability of PPID should be considered in interpretation of diagnostic test results; (v) pre-test probability of PPID is low in equids aged <10 years; (vi) both pre-test probability of disease and season of testing have strong influence on the ability to diagnose PPID using basal adrenocorticotropic hormone (ACTH) or ACTH after thyrotropin-releasing hormone (TRH) stimulation. The overall diagnostic accuracy of basal ACTH concentrations for diagnosing PPID ranged between 88% and 92% in the autumn and 70% and 86% in the non-autumn, depending on the pre-test probability. Based on a single study, the overall diagnostic accuracy of ACTH concentrations in response to TRH after 30 minutes for diagnosing PPID ranged between 92% and 98% in the autumn and 90% and 94% in the non-autumn, depending on the pre-test probability. Thus, it should be remembered that the risk of a false positive result increases in situations where there is a low pre-test probability, which could mean that treatment is initiated for PPID without checking for a more likely alternative diagnosis. This could compromise horse welfare due to the commencement of lifelong therapy and/or failing to identify and treat an alternative potentially life-threatening condition. (B) Interpretation of diagnostic tests: (i) There is a significant effect of breed on plasma ACTH concentration, particularly in the autumn with markedly higher ACTH concentrations in some but not all 'thrifty' breeds; (ii) basal and/or post-TRH ACTH concentrations may also be affected by latitude/location, diet/feeding, coat colour, critical illness and trailer transport; (iii) mild pain is unlikely to have a large effect on basal ACTH, but caution may be required for more severe pain; (iv) determining diagnostic thresholds that allow for all possible contributory factors is not practical; therefore, the use of equivocal ranges is supported; (v) dynamic insulin testing and TRH stimulation testing may be combined, but TRH stimulation testing should not immediately follow an oral sugar test; (vi) equids with PPID and hyperinsulinaemia appear to be at higher risk of laminitis, but ACTH is not an independent predictor of laminitis risk. (C) Pharmacologic treatments and other treatment/management options: (i) Pergolide improves most clinical signs associated with PPID in the majority of affected animals; (ii) Pergolide treatment lowers basal ACTH concentrations and improves the ACTH response to TRH in many animals, but measures of insulin dysregulation (ID) are not altered in most cases; (iii) chasteberry has no effect on ACTH concentrations and there is no benefit to adding chasteberry to pergolide therapy; (iv) combination of cyproheptadine with pergolide is not superior to pergolide alone; (v) there is no evidence that pergolide has adverse cardiac effects in horses; (vi) Pergolide does not affect insulin sensitivity. (D) Monitoring pergolide-treated cases: (i) Hormone assays provide a crude indication of pituitary control in response to pergolide therapy, however it is unknown whether monitoring of ACTH concentrations and titrating of pergolide doses accordingly is associated with improved endocrinological or clinical outcome; (ii) it is unknown whether monitoring the ACTH response to TRH or clinical signs is associated with an improved outcome; (iii) there is very weak evidence to suggest that increasing pergolide dose in autumn months may be beneficial; (iv) there is little advantage in waiting for more than a month to perform follow-up endocrine testing following initiation of pergolide therapy; there may be merit in performing repeat tests sooner; (v) timing of sampling in relation to pergolide dosing does not confound measurement of ACTH concentration; (vi) there is no evidence that making changes after interpretation of ACTH concentrations measured at certain times of the year is associated with improved outcomes; (vii) evidence is very limited, however, compliance with PPID treatment appears to be poor and it is unclear whether this influences clinical outcome; (viii) evidence is very limited, but horses with clinical signs of PPID are likely to shed more nematode eggs than horses without clinical signs of PPID; it is unclear whether this results in an increased risk of parasitic disease or whether there is a need for more frequent assessment of faecal worm egg counts. MAIN LIMITATIONS Limited relevant publications in the veterinary scientific literature. CONCLUSIONS These findings should be used to inform decision-making in equine primary care practice.
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Affiliation(s)
| | - Heidi E Banse
- School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Aimi Duff
- Rainbow Equine Hospital, North Yorkshire, UK
| | | | - Joanne L Ireland
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Wirral, UK
| | | | - Dianne McFarlane
- College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
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Clark BL, Norton EM, Bamford NJ, Randhawa IAS, Kemp KL, McCue ME, Bertin FR, Stewart AJ. Epidemiological investigation of insulin dysregulation in Shetland and Welsh ponies in Australia. Equine Vet J 2024; 56:281-290. [PMID: 38173146 DOI: 10.1111/evj.14044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024]
Abstract
BACKGROUND Insulin dysregulation (ID) is central to equine metabolic syndrome. There are limited epidemiological studies investigating dynamic testing of ID in ponies. OBJECTIVES To evaluate prevalence and risk factors for ID through dynamic testing of hyperinsulinaemia (DHI) and insulin resistance (IR). STUDY DESIGN Cross-sectional. METHODS Sex, age, breed, height, cresty neck score (CNS), body condition score (BCS), laminitis, HMGA2:c.83G>A genotype and pituitary pars intermedia dysfunction (PPID) status were documented. Dynamic hyperinsulinaemia was diagnosed with an oral sugar test (OST) and IR with an insulin tolerance test (ITT). Owners completed surveys reporting activity, laminitis history and perception of body condition using a (1-9) visual analogue scale (VASo). Ordinal scores were converted to binary outcomes for CNS (≤2/5 or ≥3/5), BCS and VASo (≤6/9 or ≥7/9). Variables associated with insulin concentrations, glucose reduction after the ITT and laminitis were evaluated with mixed effects regression models accounting for random effects of farms. RESULTS Among 167 ponies tested, median (range) age was 9 (4-21) years and BCS was 6 (4-8). Prevalence (95% confidence interval [CI]) of ID was 61 (53-68)%. Factors associated with insulin concentrations (estimate [95% CI]; μIU/mL) 60 min post-OST were: age (1.07 [1.02-1.11]), CNS (≥3/5, 1.52 [1.04-2.23]) and VASo (≥7/9, 1.75 [1.09-2.79]); and 90 min post-OST were: age (1.08 [1.03-1.12]), CNS (≥3/5, 1.80 [1.22-2.64]), VASo (≥7/9, 2.49 [1.52-4.08]) and sex (male, 0.64 [0.45-0.91]). Factors associated with glucose reduction after the ITT (estimate [95% CI]; %) were: age (-1.34 [-2.01 to -0.67]), sex (female, -6.21 [-11.68 to -0.74]) and VASo (≥7/9, -1.74 [-18.89 to -4.78]). Factors associated with laminitis (odds ratio [95% CI]) were DHI (4.60 [1.68-12.58]), IR (3.66 [1.26-10.61]) and PPID (11.75 [1.54-89.40]). MAIN LIMITATIONS Single time-point sampling, laminitis definition and diet analysis. CONCLUSIONS Ageing, being female and owner-perceived obesity were associated with ID.
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Affiliation(s)
- Brianna L Clark
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Elaine M Norton
- College of Agricultural and Life Sciences, The University of Arizona, Tucson, Arizona, USA
| | - Nicholas J Bamford
- Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Imtiaz A S Randhawa
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Kate L Kemp
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Molly E McCue
- College of Veterinary Medicine, The University of Minnesota, St Paul, Minnesota, USA
| | - François-René Bertin
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Allison J Stewart
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
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5
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Li FI, Spence RJ, de Laat MA, Harris PA, Sonntag J, Menzies-Gow NJ, Durham AE, Bailey SR, Sillence MN. Association between insulin dysregulation and adrenocorticotropic hormone in aged horses and ponies with no clinical signs of pituitary pars intermedia dysfunction. Equine Vet J 2023; 55:1003-1011. [PMID: 36641787 DOI: 10.1111/evj.13925] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 01/05/2023] [Indexed: 01/16/2023]
Abstract
BACKGROUND High concentrations of adrenocorticotropic hormone (ACTH) are used as an indicator of pituitary pars intermedia dysfunction (PPID), but other factors that may influence ACTH need to be understood, if diagnostic reference ranges for ACTH are to be used with confidence. Insulin dysregulation (ID) could be one such factor, as insulin affects pituitary hormones in other species. OBJECTIVES To test the hypothesis that a relationship exists between high insulin and high ACTH in aged (>15-year-old) animals with no clinical signs of PPID. STUDY DESIGN A cohort study. METHODS Thirteen horses and eleven ponies (17-25 years-old; mares and geldings) were clinically examined for signs of PPID in the spring (November 2020) and autumn (April 2021). On the same day, blood samples were taken before and 2 h after an oral glucose test (OGT). Concentrations of insulin, glucose, ACTH and cortisol were measured. RESULTS There was no association between ACTH and cortisol. However, there was a positive linear correlation between ACTH and post-OGT (insulin in the autumn (r = 0.427, p = 0.04). Two horses and six ponies had ACTH above the cut-off value for PPID diagnosis, and of these eight animals, six also had insulin concentrations above the cut-off value for ID. MAIN LIMITATIONS The cohort was small and thyrotropin-releasing hormone (TRH) stimulation tests were not performed. CONCLUSIONS In autumn, high ACTH was associated with ID, when no clinical signs of PPID were present. Because ACTH is used in PPID diagnosis, further work is required to understand this interaction.
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Affiliation(s)
- Fang I Li
- School of Biology & Environmental Science, Science Faculty, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Robert J Spence
- School of Biology & Environmental Science, Science Faculty, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Melody A de Laat
- School of Biology & Environmental Science, Science Faculty, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Patricia A Harris
- Equine Studies Group, Waltham Petcare Science Institute, Leicestershire, UK
| | - Johanna Sonntag
- Boehringer Ingelheim Vetmedica GmbH, Ingelheim am Rhein, Germany
| | | | | | - Simon R Bailey
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Martin N Sillence
- School of Biology & Environmental Science, Science Faculty, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
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6
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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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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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9
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Drozdzewska K, Gehlen H. Markers for internal neoplasia in the horse. Vet Med Sci 2022; 9:132-143. [PMID: 36495211 PMCID: PMC9857019 DOI: 10.1002/vms3.1042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The diagnosis of internal neoplasia in horses is challenging. Increased production of hormones physiologic for adult animals (e.g., adrenocorticotropin, norepinephrine, and erythropoietin) or typical for the foetal phase (alpha-fetoprotein, anti-Müllerian hormone, and parathyroid-hormone-related protein) might aid in tumour diagnostics. Thymidine kinase-1 and alkaline phosphatase are examples of intracellular enzymes, whose activity in the blood may increase in some neoplasia cases. Furthermore, inappropriate production of abnormal monoclonal or autologous antibodies can accompany lymphoma and multiple myeloma. Many of those tumour markers lead to clinical or laboratory changes, called paraneoplastic syndromes, such as hypercalcaemia and erythrocytosis. The interpretation of the results of the tumour marker measurements in horses is complicated due to many factors affecting the markers' concentration or activity (e.g., young age, pregnancy, and inflammation) and other diseases triggering the same changes. Moreover, the presence of paraneoplastic syndromes is inconsistent, which leads to low sensitivity of those substances as tumour markers. In conclusion, screening for neoplasia in horses is not recommended. The measurement of tumour markers should be performed only in risk groups with suspicious clinical or laboratory findings, and the results should be interpreted with caution. It is advisable to add inflammatory markers to the tumour profile or repeat the measurements.
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Affiliation(s)
| | - Heidrun Gehlen
- Equine Clinic, Surgery and RadiologyFreie Universitaet BerlinBerlinGermany
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10
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Pituitary Pars Intermedia Dysfunction (PPID) in Horses. Vet Sci 2022; 9:vetsci9100556. [PMID: 36288169 PMCID: PMC9611634 DOI: 10.3390/vetsci9100556] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/25/2022] [Accepted: 10/04/2022] [Indexed: 12/12/2022] Open
Abstract
Substantial morbidity results from pituitary pars intermedia dysfunction (PPID) which is often underestimated by owners and veterinarians. Clinical signs, pathophysiology, diagnostic tests, and treatment protocols of this condition are reviewed. The importance of improved recognition of early clinical signs and diagnosis are highlighted, as initiation of treatment will result in improved quality of life. Future research should be targeted at improving the accuracy of the diagnosis of PPID, as basal adrenocorticotropic hormone (ACTH) concentration can lack sensitivity and thyrotropin releasing hormone (TRH) used to assess ACTH response to TRH stimulation is not commercially available as a sterile registered product in many countries. The relationship between PPID and insulin dysregulation and its association with laminitis, as well as additional management practices and long-term responses to treatment with pergolide also require further investigation.
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Nitzsche AM, Fey K, Büttner K, Gröf M, Staszyk C. The Gingiva of Horses With Pituitary Pars Intermedia Dysfunction: A Macroscopic Anatomical Evaluation. Front Vet Sci 2022; 8:786971. [PMID: 35146012 PMCID: PMC8821874 DOI: 10.3389/fvets.2021.786971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/10/2021] [Indexed: 11/13/2022] Open
Abstract
Pituitary pars intermedia dysfunction (PPID) is a common neurodegenerative disease mainly in horses older than 15 years. The domestic equine population is following the same demographic change as that seen in humans; it is aging and veterinarians are asked to attend to geriatric horses more frequently. Common problems seen regularly in older equines are dental disorders and especially periodontal disease. As a systemic and endocrine disease, associated with delayed wound healing and impaired immune function, PPID should be considered before major dental treatment in aged equines is started. Possible negative effects of PPID on epithelial tissues could also affect the periodontium. Therefore, the aim of the present study was to identify gross changes in the gingiva associated with PPID. Fourteen horses with clinical signs of PPID and adenoma in the pituitary pars intermedia and 13 controls showing neither clinical signs nor PPID-associated histological changes in the pituitary gland were included. PPID-affected horses (26.9 ± 0.73 years) were significantly older than controls (20.0 ± 1.24 years). In the PPID-affected group, significantly more often an irregular and bulky appearance of the gingival texture was observed, as well as an irregular shape of the gingival margin. Furthermore, the sulcus gingivalis of cheek teeth frequently was deeper than 1 mm. These findings indicate a possible association between age, soft tissue alterations, and PPID and suggest a potential predisposition of PPID-affected horses for periodontal diseases.
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Affiliation(s)
- Anne Maria Nitzsche
- Equine Clinic, Internal Medicine, Faculty of Veterinary Medicine, Justus-Liebig-University, Giessen, Germany
- *Correspondence: Anne Maria Nitzsche
| | - Kerstin Fey
- Equine Clinic, Internal Medicine, Faculty of Veterinary Medicine, Justus-Liebig-University, Giessen, Germany
| | - Kathrin Büttner
- Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus-Liebig-University, Giessen, Germany
| | - Manuela Gröf
- Faculty of Veterinary Medicine, Institute of Veterinary Pathology, Justus-Liebig-University, Giessen, Germany
| | - Carsten Staszyk
- Faculty of Veterinary Medicine, Institute of Veterinary-Anatomy, -Histology and -Embryology, Justus-Liebig-University, Giessen, Germany
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12
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Sillence M, Meier A, de Laat M, Klee R, Reiche D. Demographic, morphologic, hormonal and metabolic factors associated with the rate of improvement from equine hyperinsulinaemia-associated laminitis. BMC Vet Res 2022; 18:49. [PMID: 35042535 PMCID: PMC8764787 DOI: 10.1186/s12917-022-03149-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 01/04/2022] [Indexed: 11/18/2022] Open
Abstract
Background Although several studies have investigated factors associated with the onset and occurrence of hyperinsulinaemia-associated laminitis (HAL), few have examined the factors associated with the rate of improvement during recovery from an acute bout of the disease. This observational study sought to discover if a range of demographic, morphologic, hormonal and metabolic variables are associated with the improvement rate from HAL in 37 naturally-occurring cases identified by 16 clinics across Germany. Each case was evaluated for laminitis severity on the day of inclusion in the trial (d 0), then after 4, 9, 14, 25 and 42 d. The horses were managed according to best clinical practice including restricting exercise and prescribing a diet of hay-only, for a minimum of 9 d. Blood samples were also collected during each evaluation, except on d 9, and analysed for glucose, insulin, ACTH and leptin. Results Based on individual clinical laminitis scores plotted against time, most horses improved markedly within 2 weeks, with a ‘fast group’ (n = 27) having a median (interquartile range) score on a 12-point scale of 0 (0–2) by d 14. However, there was a clear disparity within the total cohort, as ~ 1 in 4 horses demonstrated much slower improvement, with a median score of 5 (4–7) by d 14, or a marked relapse thereafter (‘slow group’, n = 10). Horses in the slow improvement group were younger (12.5 (8.8–16.3) vs 17 (14–24) yr; P = 0.008), but were not more likely to be heavier, male, very fat, to have presented with a previous history of laminitis or elevated ACTH concentrations, or to be receiving pergolide treatment. Of the hormonal and metabolic parameters measured, glucose and insulin concentrations were within the normal range following transition to the hay-only diet, but were higher in the group that failed to improve quickly, with a small but significant difference being evident on d 4, 14 and 25 for glucose (11 to 16%; P < 0.05), and a larger difference for insulin on d 14 and 25 (51 to 55%; P < 0.05). There was no difference between the groups in ACTH or leptin concentrations throughout the study. The main limitations of this study were the small number of slow-improvement horses and an inability to control or measure certain variables, such as feed quality. Conclusions Young age and a modest increase in blood glucose and insulin concentrations are associated with delayed laminitis improvement.
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13
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Rumfola E, He B, Atkins M, McGowan CM, Ireland JL. Approaches to endocrinopathic laminitis in the field: Results of a survey of veterinary practitioners in North America. J Equine Vet Sci 2021; 110:103856. [PMID: 34958881 DOI: 10.1016/j.jevs.2021.103856] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 12/18/2021] [Accepted: 12/20/2021] [Indexed: 10/19/2022]
Abstract
Endocrinopathic laminitis is the most common cause of laminitis in the field. Insulin has recently been implicated as a key factor in development of endocrinopathic laminitis; however, it is unclear whether diagnostic and treatment approaches reflect insights derived from recent research. This study sought to evaluate North American veterinary practitioners' approach to endocrinopathic laminitis in the field. Demographic information, approach to diagnosis, management, and prognosis of endocrinopathic laminitis, as well as factors influencing changes in approach to laminitis were collected. To compare regional differences in approach to laminitis, results were compared to a recently published study from the United Kingdom. Findings of the present study suggest that North American practitioners have changed their approach to laminitis to more readily incorporate diagnostic testing for endocrine disease.
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Affiliation(s)
- E Rumfola
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States 70803
| | - Banse He
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States 70803.
| | - M Atkins
- Institute of Infection, Veterinary and Ecological Sciences, Department of Equine Clinical Science, University of Liverpool, Leahurst Campus, Neston, Cheshire, CH64 7TE, United Kingdom
| | - C M McGowan
- Institute of Infection, Veterinary and Ecological Sciences, Department of Equine Clinical Science, University of Liverpool, Leahurst Campus, Neston, Cheshire, CH64 7TE, United Kingdom
| | - J L Ireland
- Institute of Infection, Veterinary and Ecological Sciences, Department of Equine Clinical Science, University of Liverpool, Leahurst Campus, Neston, Cheshire, CH64 7TE, United Kingdom
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14
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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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15
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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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16
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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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17
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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: 4] [Impact Index Per Article: 1.3] [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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18
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Knowles EJ, Grieve L. Clinical insights: Equine obesity. Equine Vet J 2020; 52:635-638. [PMID: 32748989 DOI: 10.1111/evj.13307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 06/08/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Edward J Knowles
- Royal Veterinary College Clinical Services Division, Hatfield, Hertfordshire, UK.,Bell Equine Veterinary Clinic, Maidstone, Kent, UK
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19
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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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20
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Norton E, McCue ME. Genetics of Equine Endocrine and Metabolic Disease. Vet Clin North Am Equine Pract 2020; 36:341-352. [PMID: 32534851 DOI: 10.1016/j.cveq.2020.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
A role for a genetic contribution to equine metabolic syndrome (EMS) and pars pituitary intermedia dysfunction (PPID) has been hypothesized. Heritability estimates of EMS biochemical measurements were consistent with moderately to highly heritable traits. Further, genome-wide association analyses have identified hundreds of regions of the genome contributing to EMS and candidate variants have been identified. The genetics of PPID has not yet been proven. Continued research for the specific genetic risk factors for both EMS and PPID is crucial for gaining a better understanding of the pathophysiology of both conditions and allowing development of genetic tests.
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Affiliation(s)
- Elaine Norton
- Veterinary Population Medicine Department, University of Minnesota, 225 Veterinary Medical Center, 1365 Gortner Avenue, St Paul, MN 55108, USA.
| | - Molly E McCue
- Veterinary Population Medicine Department, University of Minnesota, 225 Veterinary Medical Center, 1365 Gortner Avenue, St Paul, MN 55108, USA
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21
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Legere RM, Taylor DR, Davis JL, Bello K, Parker C, Judd RL, Wooldridge AA. Pharmacodynamic Effects of Pioglitazone on High Molecular Weight Adiponectin Concentrations and Insulin Response After Oral Sugar in Equids. J Equine Vet Sci 2019; 82:102797. [PMID: 31732109 DOI: 10.1016/j.jevs.2019.102797] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/17/2019] [Accepted: 09/16/2019] [Indexed: 10/26/2022]
Abstract
Chronic insulin dysregulation is challenging to manage with pharmaceuticals in horses. Pioglitazone improves insulin sensitivity in humans, and the pharmacokinetics of pioglitazone have been evaluated in horses. The objectives of this study were to assess the pharmacodynamic effects of oral pioglitazone on morphometric parameters, hepatic enzyme activity and function, adipokines, and enteroinsular response to oral sugar. A prospective pilot study was performed using fifteen adult equids (8 ponies, 7 horses) to evaluate the effects of short-term pioglitazone administration (2 mg/kg PO q 24 hours, 28 days). Oral sugar tests (OST) were performed before and after treatment. Adipokines were measured at day 0, 14, and 28 of administration. Plasma drug concentrations were measured at day 14 and 28 of administration. The subjects were grouped into horses, ponies, and insulin dysregulated (ID) animals. Baseline values for all parameters were compared with values obtained at day 14 and 28 using one-way or two-way analysis of variance. Mild changes were noted in morphometric parameters and hepatic enzymes. No differences were found in leptin concentrations or the blood glucose response to the OST. Significant decreases were found in the insulin response to OST at 90 and 120 minutes time points and the area under the curve after pioglitazone treatment in the pony and ID groups. High-molecular-weight (HMW) adiponectin concentrations were significantly increased in all groups after pioglitazone treatment. Decreased insulin concentrations in response to oral sugar and increased HMW adiponectin concentrations indicate positive effects of pioglitazone for treatment of metabolic derangements in equine metabolic syndrome, which warrant future clinical study.
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Affiliation(s)
- Rebecca M Legere
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL
| | - Debra R Taylor
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL
| | - Jennifer L Davis
- Department of Biomedical Sciences & Pathobiology, VA-MD College of Veterinary Medicine, Blacksburg, VA
| | - Kaitlyn Bello
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL
| | - Caroline Parker
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL
| | - Robert L Judd
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL
| | - Anne A Wooldridge
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL.
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22
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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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23
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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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24
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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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25
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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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de Laat MA, Sillence MN, Reiche DB. Phenotypic, hormonal, and clinical characteristics of equine endocrinopathic laminitis. J Vet Intern Med 2019; 33:1456-1463. [PMID: 30697823 PMCID: PMC6524085 DOI: 10.1111/jvim.15419] [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: 08/16/2018] [Accepted: 01/09/2019] [Indexed: 02/06/2023] Open
Abstract
Background Equine endocrinopathic laminitis is common and can be associated with an underlying endocrinopathy, such as equine metabolic syndrome (EMS), pituitary pars intermedia dysfunction (PPID), pasture consumption, or any combination of these factors. Objectives The aim of the study was to improve the risk assessment capabilities of clinicians, and to inform management strategies, for acute endocrinopathic laminitis by prospectively examining the phenotypic, hormonal, and clinical characteristics of the disease in a large cohort. Animals Privately owned horses and ponies (n = 301) of any age, sex, or breed diagnosed with laminitis by a veterinarian. A history of laminitis was acceptable. Methods This was a prospective cohort study. Veterinarians provided information on each case via an online questionnaire after informed consent from the animal's owner, and all data were de‐identified before analysis. Serum insulin and plasma adrenocorticotrophic hormone concentrations were measured in each case. Results Most cases were recruited in spring (109/301; 36.2%). Concurrent EMS and PPID resulted in higher basal insulin concentrations (49 [21.5‐141]; P < .02) than if an animal had a single underlying cause for their laminitis. The insulin concentration was negatively correlated (r2 = −0.38; P < .001) with the animal's height, being higher in ponies (33[10‐14]; P < .001) than horses (9.5 [3‐25.7]) and was positively correlated (r2 = 0.12; P = .05) with their grade (severity) of laminitis. Conclusions and Clinical Importance Horses and ponies with concurrent endocrinopathies have more marked hyperinsulinemia. Higher basal insulin concentrations were associated with more severe lameness.
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Affiliation(s)
- Melody A de Laat
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Martin N Sillence
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Dania B Reiche
- Animal Health, Boehringer Ingelheim Vetmedica GmbH, Ingelheim am Rhein, Germany
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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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Horn R, Bamford NJ, Afonso T, Sutherland M, Buckerfield J, Tan RHH, Secombe CJ, Stewart AJ, Bertin FR. Factors associated with survival, laminitis and insulin dysregulation in horses diagnosed with equine pituitary pars intermedia dysfunction. Equine Vet J 2018; 51:440-445. [DOI: 10.1111/evj.13041] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 11/02/2018] [Indexed: 12/29/2022]
Affiliation(s)
- R. Horn
- School of Veterinary Science The University of Queensland Gatton Queensland Australia
| | - N. J. Bamford
- Faculty of Veterinary and Agricultural Sciences The University of Melbourne Werribee Victoria Australia
| | - T. Afonso
- School of Animal and Veterinary Sciences The University of Adelaide Roseworthy South Australia Australia
| | - M. Sutherland
- Gisborne Veterinary Clinic Gisborne Victoria Australia
| | | | - R. H. H. Tan
- College of Public Health, Medical and Veterinary Sciences James Cook University Townsville Queensland Australia
- Samford Valley Veterinary Hospital Samford Queensland Australia
| | - C. J. Secombe
- School of Veterinary and Life Sciences Murdoch University Perth Western Australia Australia
| | - A. J. Stewart
- School of Veterinary Science The University of Queensland Gatton Queensland Australia
| | - F. R. Bertin
- School of Veterinary Science The University of Queensland Gatton Queensland 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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31
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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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Lewis SL, Holl HM, Long MT, Mallicote MF, Brooks SA. Use of principle component analysis to quantitatively score the equine metabolic syndrome phenotype in an Arabian horse population. PLoS One 2018; 13:e0200583. [PMID: 30001422 PMCID: PMC6042766 DOI: 10.1371/journal.pone.0200583] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/01/2018] [Indexed: 11/28/2022] Open
Abstract
Equine metabolic syndrome (EMS), like human metabolic syndrome, comprises a collection of clinical signs related to obesity, insulin dysregulation and susceptibility to secondary inflammatory disease. Although the secondary conditions resulting from EMS can be life-threatening, diagnosis is not straightforward and often complicated by the presence of other concurrent conditions like pituitary pars intermedia dysfunction (PPID). In order to better characterize EMS, we sought to describe the variation within, and correlations between, typical physical and endocrine parameters for EMS. Utilizing an unsupervised statistical approach, we evaluated a population of Arabian horses using a physical examination including body measurements, as well as blood plasma insulin, leptin, ACTH, glucose, and lipid values. We investigated the relationships among these variables using principle component analysis (PCA), hierarchical clustering, and linear regression. Owner-assigned assessments of body condition were one full score (on a nine-point scale) lower than scores assigned by researchers, indicating differing perception of healthy equine body weight. Rotated PCA defined two factor scores explaining a total of 46.3% of variation within the dataset. Hierarchical clustering using these two factors revealed three groups corresponding well to traditional diagnostic categories of "Healthy", "PPID-suspect", and "EMS-suspect" based on the characteristics of each group. Proxies estimating up to 93.4% of the composite "EMS-suspect" and "PPID-suspect" scores were created using a reduced set of commonly used diagnostic variables, to facilitate application of these quantitative scores to horses of the Arabian breed in the field. Use of breed-specific, comprehensive physical and endocrinological variables combined in a single quantitative score may improve detection of horses at-risk for developing EMS, particularly in those lacking severe clinical signs. Quantification of EMS without the use of predetermined reference ranges provides an advantageous approach for future studies utilizing genomic or metabolomics approaches to improve understanding of the etiology behind this troubling condition.
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Affiliation(s)
- Samantha L. Lewis
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States of America
| | - Heather M. Holl
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States of America
| | - Maureen T. Long
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States of America
| | - Martha F. Mallicote
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States of America
| | - Samantha A. Brooks
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States of America
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33
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Tadros EM, Fowlie JG, Refsal KR, Marteniuk J, Schott HC. Association between hyperinsulinaemia and laminitis severity at the time of pituitary pars intermedia dysfunction diagnosis. Equine Vet J 2018; 51:52-56. [PMID: 29761574 DOI: 10.1111/evj.12963] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 05/04/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Hyperinsulinaemia is the suspected component of insulin dysregulation having the strongest association with laminitis and occurs variably in equids with pituitary pars intermedia dysfunction (PPID). OBJECTIVES We hypothesised that magnitude of hyperinsulinaemia correlates with laminitis severity in PPID-affected equids. Furthermore, we hypothesised that owners can be unaware of chronic endocrinopathic laminitis. STUDY DESIGN Cross-sectional study. METHODS Serum insulin concentrations, owner-reported laminitis history and radiographic evidence of laminitis were determined in 38 client-owned horses and ponies with confirmed PPID. Laminitis severity was classified into four categories (normal [nonlaminitic], mild, moderate or severe laminitis) based on degree of distal phalangeal rotation. Animals were also categorised as normoinsulinaemic (<20 μU/ml), mildly hyperinsulinaemic (20-50 μU/ml) and severely hyperinsulinaemic (>50 μU/ml). One-way ANOVA, t tests and Fisher's exact tests were performed. RESULTS While owners reported laminitis in 37% of animals, 76% were laminitic based on study criteria (P = 0.01). Owners reported laminitis more frequently in hyperinsulinaemic vs. normoinsulinaemic animals; recognition increased with severity of hyperinsulinaemia (P = 0.03). Mean insulin concentrations were higher in equids with moderate to severe radiographic laminitis (geometric mean 74.1, 95% confidence interval (CI) 38.4-143.1 uU/ml) vs. those classified radiographically as normal to mild (31.9, 95% CI 21.1-48.1 uU/ml P = 0.03). MAIN LIMITATIONS Dynamic insulin testing was not performed; some normoinsulinaemic animals might have had subtle insulin dysregulation. CONCLUSIONS Although radiographic abnormalities were present in most animals at the time of PPID diagnosis, chronic laminitis remained unrecognised by many owners. Owner awareness of laminitis increased with severity of hyperinsulinaemia and higher insulin concentrations were detected in association with more severe radiographic changes. The Summary is available in Chinese - See Supporting Information.
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Affiliation(s)
- E M Tadros
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, USA
| | - J G Fowlie
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA
| | - K R Refsal
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, USA
| | - J Marteniuk
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA
| | - H C Schott
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA
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34
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Secombe CJ, Bailey SR, de Laat MA, Hughes KJ, Stewart AJ, Sonis JM, Tan RHH. Equine pituitary pars intermedia dysfunction: current understanding and recommendations from the Australian and New Zealand Equine Endocrine Group. Aust Vet J 2018; 96:233-242. [DOI: 10.1111/avj.12716] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/29/2018] [Accepted: 05/02/2018] [Indexed: 12/25/2022]
Affiliation(s)
- CJ Secombe
- College of Veterinary Medicine, School of Veterinary and Life Sciences; Murdoch University; Murdoch Western Australia Australia
| | - SR Bailey
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences; The University of Melbourne; Werribee VIC Australia
| | - MA de Laat
- Science and Engineering Faculty; Queensland University of Technology; Brisbane QLD Australia
| | - KJ Hughes
- School of Animal and Veterinary Sciences; Charles Sturt University; Wagga Wagga NSW Australia
| | - AJ Stewart
- Equine Specialist Hospital, School of Veterinary Science; The University of Queensland; Gatton QLD Australia
| | - JM Sonis
- Veterinary Associates Equine and Farm, Karaka; Auckland New Zealand
| | - RHH Tan
- Samford Valley Veterinary Hospital; Samford, QLD Australia
- Discipline of Veterinary Clinical Sciences, College of Public Health, Medical and Veterinary Sciences; James Cook University; Townsville QLD Australia
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35
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Meier AD, de Laat MA, Reiche DB, Pollitt CC, Walsh DM, McGree JM, Sillence MN. The oral glucose test predicts laminitis risk in ponies fed a diet high in nonstructural carbohydrates. Domest Anim Endocrinol 2018; 63:1-9. [PMID: 29172109 DOI: 10.1016/j.domaniend.2017.10.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/24/2017] [Accepted: 10/25/2017] [Indexed: 10/18/2022]
Abstract
The aim of this study was to investigate the relationship between laminitis development in ponies and insulin/glucose concentrations in response to the oral glucose test (OGT) and a dietary challenge high in nonstructural carbohydrates (NSCs). After undergoing an OGT (1 g dextrose/kg BW in feed), 37 ponies with 2-h serum insulin concentrations ranging from 22 to 1,133 μIU/mL were subjected to a diet challenge period (DCP), consuming 12 g NSC/kg BW/d for up to 18 d. Insulin and glucose responses were measured on day 2 of the DCP. Clinical laminitis was diagnosed by blinded experts and confirmed radiographically. Basal ACTH levels and clinical signs were assessed to investigate concurrent putative pituitary pars intermedia dysfunction (PPID). The diet induced Obel grade 1 or 2 laminitis in 14 ponies (38%). The ponies that developed laminitis had higher maximum concentrations of blood glucose (P = 0.04) and serum insulin (P = 0.02) in response to the diet. The geometric mean (95% CI) blood glucose concentration for laminitis cases was 14.9 (12.9-17.2) mM, compared to 10.7 (9.2-12.5) mM for ponies who did not develop laminitis. Similarly, the geometric mean (95% CI) for serum insulin was 396 (301-520) μIU/mL for laminitis cases, compared to 216 (148-316) μIU/mL for ponies who did not develop laminitis. Laminitis incidence was likewise associated with insulin concentrations measured during the OGT. Laminitis occurred at frequencies of 0% (0/7) if postdextrose insulin (μIU/mL) was <50; 35% (8/23) if insulin was 50 to 195; and 86% (6/7) if insulin was >195 μIU/mL. Basal ACTH concentrations were above seasonally accepted reference ranges in 16/37 ponies, and 8 of these animals (50%) developed laminitis. This included all 5 ponies in the study that had clinical signs of PPID (100%). In contrast, hyperinsulinemia and laminitis occurred in only 3/11 ponies (27%) with elevated ACTH concentrations and no clinical signs of PPID (P = 0.009). Thus, laminitis occurrence was associated with higher glucose and insulin responses to both the OGT and challenge diet, and the frequency of laminitis can be predicted based on insulin and glucose hyperresponsiveness to these oral carbohydrate challenges.
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Affiliation(s)
- A D Meier
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Queensland, Australia
| | - M A de Laat
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Queensland, Australia
| | - D B Reiche
- Boehringer Ingelheim Vetmedica, Ingelheim am Rhein, Germany
| | - C C Pollitt
- Australian Equine Laminitis Research Unit, School of Veterinary Science, University of Queensland, Queensland, Australia
| | - D M Walsh
- Animal Health Foundation, Pacific, Missouri, USA
| | - J M McGree
- School of Mathematical Sciences, Queensland University of Technology, Queensland, Australia
| | - M N Sillence
- Earth, Environmental and Biological Sciences School, Queensland University of Technology, Queensland, Australia.
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Patterson-Kane JC, Karikoski NP, McGowan CM. Paradigm shifts in understanding equine laminitis. Vet J 2017; 231:33-40. [PMID: 29429485 DOI: 10.1016/j.tvjl.2017.11.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 10/08/2017] [Accepted: 11/20/2017] [Indexed: 12/29/2022]
Abstract
Laminitis, one of the most debilitating conditions of all equids, is now known to be the result of several systemic disease entities. This finding, together with other recent developments in the field of laminitis research, have provoked a rethink of our clinical and research strategies for this condition. First, laminitis is now considered to be a clinical syndrome associated with systemic disease (endocrine disease, sepsis or systemic inflammatory response syndrome, SIRS) or altered weight bearing rather than being a discrete disease entity. Next, laminitis associated with endocrine disease (endocrinopathic laminitis) is now believed to be the predominant form in animals presenting (primarily) for lameness. Third, the designation of laminitis as a primary and severe basement membrane pathology now requires revision. Instead, current data now proposes a variable subclinical phase associated with gross changes in the hoof capsule, with stretching and elongation of the lamellar cells an early and key event in the pathophysiology. These findings have fuelled new mechanistic hypotheses and research directions that will be discussed, together with their implications for future clinical management.
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Affiliation(s)
| | - N P Karikoski
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Viikintie49, FIN-00014 Helsinki, Finland
| | - C M McGowan
- Institutes of Veterinary Science and Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Leahurst CH64 7TE, UK.
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Lane HE, Burns TA, Hegedus OC, Watts MR, Weber PS, Woltman KA, Geor RJ, McCutcheon LJ, Eades SC, Mathes LE, Belknap JK. Lamellar events related to insulin‐like growth factor‐1 receptor signalling in two models relevant to endocrinopathic laminitis. Equine Vet J 2017; 49:643-654. [DOI: 10.1111/evj.12663] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 01/04/2017] [Indexed: 12/20/2022]
Affiliation(s)
- H. E. Lane
- Department of Veterinary Clinical Sciences College of Veterinary Medicine Ohio State University Columbus Ohio USA
| | - T. A. Burns
- Department of Veterinary Clinical Sciences College of Veterinary Medicine Ohio State University Columbus Ohio USA
| | - O. C. Hegedus
- Department of Veterinary Clinical Sciences College of Veterinary Medicine Ohio State University Columbus Ohio USA
| | - M. R. Watts
- Department of Veterinary Clinical Sciences College of Veterinary Medicine Ohio State University Columbus Ohio USA
| | - P. S. Weber
- Department of Large Animal Clinical Sciences College of Veterinary Medicine Michigan State University East Lansing Michigan USA
| | - K. A. Woltman
- Department of Large Animal Clinical Sciences College of Veterinary Medicine Michigan State University East Lansing Michigan USA
| | - R. J. Geor
- Department of Large Animal Clinical Sciences College of Veterinary Medicine Michigan State University East Lansing Michigan USA
| | - L. J. McCutcheon
- Department of Large Animal Clinical Sciences College of Veterinary Medicine Michigan State University East Lansing Michigan USA
| | - S. C. Eades
- Department of Veterinary Clinical Sciences School of Veterinary Medicine Louisiana State University Baton Rouge Louisiana USA
| | - L. E. Mathes
- Department of Veterinary Clinical Sciences College of Veterinary Medicine Ohio State University Columbus Ohio USA
- Department of Veterinary Biosciences College of Veterinary Medicine Ohio State University Columbus Ohio USA
| | - J. K. Belknap
- Department of Veterinary Clinical Sciences College of Veterinary Medicine Ohio State University Columbus Ohio USA
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38
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Morgan RA, Keen JA, Walker BR, Hadoke PWF. Vascular Dysfunction in Horses with Endocrinopathic Laminitis. PLoS One 2016; 11:e0163815. [PMID: 27684374 PMCID: PMC5042533 DOI: 10.1371/journal.pone.0163815] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 09/14/2016] [Indexed: 11/19/2022] Open
Abstract
Endocrinopathic laminitis (EL) is a vascular condition of the equine hoof resulting in severe lameness with both welfare and economic implications. EL occurs in association with equine metabolic syndrome and equine Cushing’s disease. Vascular dysfunction, most commonly due to endothelial dysfunction, is associated with cardiovascular risk in people with metabolic syndrome and Cushing’s syndrome. We tested the hypothesis that horses with EL have vascular, specifically endothelial, dysfunction. Healthy horses (n = 6) and horses with EL (n = 6) destined for euthanasia were recruited. We studied vessels from the hooves (laminar artery, laminar vein) and the facial skin (facial skin arteries) by small vessel wire myography. The response to vasoconstrictors phenylephrine (10−9–10-5M) and 5-hydroxytryptamine (5HT; 10−9–10-5M) and the vasodilator acetylcholine (10−9–10-5M) was determined. In comparison with healthy controls, acetylcholine-induced relaxation was dramatically reduced in all intact vessels from horses with EL (% relaxation of healthy laminar arteries 323.5 ± 94.1% v EL 90.8 ± 4.4%, P = 0.01, laminar veins 129.4 ± 14.8% v EL 71.2 ± 4.1%, P = 0.005 and facial skin arteries 182.0 ± 40.7% v EL 91.4 ± 4.5%, P = 0.01). In addition, contractile responses to phenylephrine and 5HT were increased in intact laminar veins from horses with EL compared with healthy horses; these differences were endothelium-independent. Sensitivity to phenylephrine was reduced in intact laminar arteries (P = 0.006) and veins (P = 0.009) from horses with EL. Horses with EL exhibit significant vascular dysfunction in laminar vessels and in facial skin arteries. The systemic nature of the abnormalities suggest this dysfunction is associated with the underlying endocrinopathy and not local changes to the hoof.
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Affiliation(s)
- Ruth A. Morgan
- University/BHF Centre for Cardiovascular Science, The Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
- * E-mail:
| | - John A. Keen
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Brian R. Walker
- University/BHF Centre for Cardiovascular Science, The Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Patrick W. F. Hadoke
- University/BHF Centre for Cardiovascular Science, The Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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Abstract
Laminitis is one of the most common and frustrating clinical presentations in equine practice. While the principles of treatment for laminitis have not changed for several decades, there have been some important paradigm shifts in our understanding of laminitis. Most importantly, it is essential to consider laminitis as a clinical sign of disease and not as a disease in its own right. Once this shift in thinking has occurred, it is logical to then question what disease caused the laminitis. More than 90 per cent of horses presented with laminitis as their primary clinical sign will have developed it as a consequence of endocrine disease; most commonly equine metabolic syndrome (EMS). Given the fact that many horses will have painful protracted and/or chronic recurrent disease, a good understanding of the predisposing factors and how to diagnose and manage them is crucial. Current evidence suggests that early diagnosis and effective management of EMS should be a key aim for practising veterinary surgeons to prevent the devastating consequences of laminitis. This review will focus on EMS, its diagnosis and management.
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Affiliation(s)
- R Morgan
- BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - J Keen
- European Specialist in Equine Internal Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian EH25 9RG, UK
| | - C McGowan
- European Specialist in Equine Internal Medicine, Institute of Aging and Chronic Disease, University of Liverpool, Leahurst Campus, Neston, Cheshire CH64 7TE, UK
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