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Nielsen MK, Finnerty CA, Ripley NE, Page AE, McClendon ME, Adams AA. Ivermectin performance in horses diagnosed with equine endocrine disorders. Vet Parasitol 2024; 328:110182. [PMID: 38603925 DOI: 10.1016/j.vetpar.2024.110182] [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: 02/01/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024]
Abstract
Anthelmintic performance against equine cyathostomins can be evaluated by two different non-terminal measures; the Fecal Egg Count Reduction Test (FECRT) and the Egg Reappearance Period (ERP). Most available FECRT and ERP data have been determined in populations of young horses, and very little information is available from mature and senior horses. Furthermore, it is unknown how commonly occurring equine endocrine disorders such as Insulin dysregulation (ID) and Pituitary pars intermedia dysfunction (PPID) may interfere with these measurements, but it has been suggested that horses with these conditions could be more susceptible to parasitic infections. A research population of senior horses and horses with or without PPID, ID, or both were enrolled in this study. All strongylid egg count positive horses were included in an ivermectin (200 μg/kg) efficacy study. These were distributed among the following groups: ID: six, PPID: three, PPID and ID: seven, and healthy controls: three. Strongylid fecal egg counts were determined on the day of ivermectin administration, at two weeks post deworming, and on weekly intervals until eight weeks post treatment. Determination of FECRT and ERP were carried out following World Association for the Advancement of Veterinary Parasitology guidelines. Results revealed high ivermectin efficacy with mean egg count reduction at 99.7% or above in all groups at two weeks post treatment. Egg reappearance was documented at six and seven weeks in the ID and PPID/ID groups, respectively, whereas the PPID and healthy control groups both had ERP at 8 weeks. Statistical analysis found no significant differences in egg count levels between groups during the study. The expected ERP for ivermectin is 8-10 weeks, meaning that two of the groups displayed shortened ERPs. However, due to the small group sizes, these data should be interpreted with caution. Nonetheless, results do indicate a need for further investigation of the possible influence of endocrine disorders on anthelmintic performance in horses.
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Affiliation(s)
- M K Nielsen
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA.
| | - C A Finnerty
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA
| | - N E Ripley
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA
| | - A E Page
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA
| | - M E McClendon
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA
| | - A A Adams
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, 1400 Nicholasville Rd, Lexington, KY 40503, USA
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Xue C, Davis J, Berghaus LJ, Hanafi A, Vaughn SA, Hart KA. Pharmacokinetic properties of pergolide mesylate following single and multiple-dose administration in donkeys (Equus asinus). Equine Vet J 2023; 55:1078-1085. [PMID: 36572900 DOI: 10.1111/evj.13917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 12/07/2022] [Indexed: 12/28/2022]
Abstract
BACKGROUND Donkeys with clinical signs of pituitary pars intermedia dysfunction are treated with oral pergolide mesylate despite the lack of species-specific pharmacokinetic data. OBJECTIVE To evaluate the pharmacokinetics of intragastric and oral pergolide mesylate in healthy donkeys (Equus asinus). STUDY DESIGN Pharmacokinetic study. METHODS Six healthy donkeys were administered pergolide mesylate (Prascend®) at 2 μg/kg bodyweight (bwt) intragastrically once, then once daily per os (PO) for 5 days. Blood samples were collected at 0, 10, 20, 30 and 45 min and 1, 1.5, 2, 3, 4, 6, 8, 12, 24, 36 and 48 h after the single intragastric dose, once daily immediately before the PO dose, and then again at the above times after Day 5 of once daily oral dosing. Plasma pergolide concentration was quantified via ultra-performance liquid chromatography-tandem mass spectrometry. Pergolide concentration versus time data after the first and last doses were analysed based on noncompartmental pharmacokinetics using commercial software. Paired t-tests were used to compare single and multiple doses (p < 0.05). In a follow-up study, a single oral dose was then administered to two donkeys followed by concurrent blood sampling from the jugular and cephalic veins to evaluate the effect of route of administration on pergolide pharmacokinetics. RESULTS Cmax , Tmax AUC, and t½λz differed significantly (p ≤ 0.03) after single and multiple doses, with significantly lower Cmax (0.16 ± 0.16 ng/ml) and t½λz (9.74 ± 1.35 h) after intragastric dosing on Day 1 than after 5 days of oral dosing (3.74 ± 2.26 ng/ml and 16.35 ± 5.21 h, respectively). Pergolide plasma concentrations were higher in jugular vein samples compared to cephalic vein samples after a single oral dose. MAIN LIMITATIONS Small sample size; varied administration routes. CONCLUSIONS Pergolide mesylate (dosed at 2 μg/kg bwt) is bioavailable in donkeys after intragastric and PO administration. Differences in pharmacokinetics were noted after multiple doses, related to different routes of administration and sublingual absorption of pergolide.
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Affiliation(s)
- Cynthia Xue
- Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
| | - Jennifer Davis
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia, USA
| | - Londa J Berghaus
- Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
| | - Amanda Hanafi
- Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
| | - Sarah A Vaughn
- Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
| | - Kelsey A Hart
- Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
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Adams AA, Siard-Altman MH, Reedy SE, Barker D, Elzinga S, Sanz MG, Urschel K, Ireland JL. Evaluation of seasonal influences on adrenocorticotropic hormone response to the thyrotropin-releasing hormone stimulation test and its accuracy for diagnosis of pituitary pars intermedia dysfunction. Vet J 2023; 300-302:106035. [PMID: 37802466 DOI: 10.1016/j.tvjl.2023.106035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 09/26/2023] [Accepted: 10/03/2023] [Indexed: 10/10/2023]
Abstract
Pituitary pars intermedia dysfunction (PPID) is an age-related neurodegenerative disorder, affecting >20 % of older horses. There is a need for improved endocrine tests for early disease detection, and the thyrotropin-releasing hormone (TRH) stimulation test has been recommended for diagnosis of early or mild cases. However, it is currently not recommended for year-round use due to marked seasonal variability. The aims of this cohort study were to evaluate effects of month and season on adrenocorticotropic hormone (ACTH) responses to TRH stimulation and to derive monthly cut-offs for PPID diagnosis. Sixty-three horses were assigned to control (n = 17), subclinical PPID (n = 21) and clinical PPID (n = 25) groups, based on a composite reference standard that combined clinical history and examination findings with endocrine test results. TRH stimulation tests were performed monthly for a 12-month period. Circannual changes were evaluated with one- and two-way repeated-measures analysis of variance and receiver operating characteristic curve analysis was used to derive cut-off values for basal and TRH-stimulated ACTH. TRH-stimulated ACTH concentrations were lowest in February-May and highest in August-October. Specificity of both basal and 30 min post-TRH ACTH was generally higher than sensitivity, and TRH stimulation had improved diagnostic accuracy compared to basal ACTH, although its sensitivity was not significantly greater year-round. TRH stimulation tests yielded considerably more positive results than basal ACTH in the subclinical group, but few additional positive results in clinical PPID cases. There were large differences between cut-offs that maximised sensitivity or specificity for TRH-stimulated ACTH, highlighting the importance of considering clinical presentation alongside test results in diagnostic decision-making.
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Affiliation(s)
- A A Adams
- Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546, USA
| | - M H Siard-Altman
- Equine Studies, Department of Science & Health, Asbury University, One Macklem Drive, Wilmore, KY 40390, USA
| | - S E Reedy
- Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546, USA
| | - D Barker
- Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546, USA
| | - S Elzinga
- Neurology Department, Michigan Medicine, University of Michigan, Ann Arbor, MI 48103, USA
| | - M G Sanz
- Washington Animal Disease Diagnostic Laboratory, Washington State University,1940 SE Olympia Ave, Pullman, WA 99164-7034, USA
| | - K Urschel
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40546-0215, USA
| | - J L Ireland
- Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and Life Sciences, The University of Liverpool, Leahurst Campus, Neston, Cheshire CH64 7TE, UK.
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Huang L, Palmieri C, Bertin FR. Correlation of pituitary histomorphometry with dopamine and dopamine D2 receptor expression in horses with pituitary pars intermedia dysfunction. Res Vet Sci 2022; 152:427-433. [PMID: 36126509 DOI: 10.1016/j.rvsc.2022.08.018] [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: 04/24/2022] [Revised: 08/09/2022] [Accepted: 08/20/2022] [Indexed: 10/15/2022]
Abstract
Pituitary pars intermedia dysfunction (PPID) is an endocrinopathy commonly affecting old horses. It is a spontaneously occurring, progressive disease that is still poorly understood. Previous studies have observed neurodegeneration of the dopaminergic inhibition of melanotrophs, which leads to decreased dopamine (DA) in the pars intermedia (PI) and increased pro-opiomelanocortin-derived peptides circulating in plasma. However, rats knockout for the dopamine D2 receptor (D2r) similarly develop PI hypertrophy and hyperplasia. Thus, based on the current pathophysiological theory of PPID, whether the decreased DA or the D2r dysfunction leads to PPID is still unclear. To test this, a total of 28 retrospective cases of horses with PPID were collected, graded and the expression of tyrosine hydroxylase (TH) and D2r in the PI were determined. The histological and immunohistochemical results demonstrated that horses with higher tumor histological grades had reduced TH expression with increased D2r immunoreactivity colocalized in the PI (p < 0.001, p < 0.05 respectively). This correlation supports the role of DA in the pathogenesis of continuous unregulated proliferation of neoplastic cells in PI and indicates the efficiency of D2r agonists as a treatment for PPID.
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Affiliation(s)
- Luoyi Huang
- School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia.
| | - Chiara Palmieri
- School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia.
| | - François-René Bertin
- School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia.
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Kirkwood NC, Hughes KJ, Stewart AJ. Prospective Case Series of Clinical Signs and Adrenocorticotrophin (ACTH) Concentrations in Seven Horses Transitioning to Pituitary Pars Intermedia Dysfunction (PPID). Vet Sci 2022; 9:vetsci9100572. [PMID: 36288186 PMCID: PMC9607114 DOI: 10.3390/vetsci9100572] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/29/2022] [Accepted: 10/11/2022] [Indexed: 12/31/2022] Open
Abstract
Simple Summary Pituitary pars intermedia dysfunction (PPID) is a common disease of the geriatric horse population. The most common clinical sign of PPID is hypertrichosis, or a long hair-coat with delayed shedding. Hypertrichosis is the most easily recognized clinical sign of PPID. However, the presence of hypertrichosis is often associated with severe end-stage disease. There is little research investigating sub-clinical or early PPID and the clinical signs associated with these stages of disease. The benefit of being able to recognize early PPID, is that we are able to begin treatment earlier on in disease process, potentially reducing the deleterious consequences of PPID and improving survival. Laboratory tests are available to more accurately diagnose PPID, and these tests include the basal ACTH and TRH-stimulated ACTH tests. Basal ACTH is easy to perform and is recommended in cases where clinical disease is suspected. The TRH-stimulation test improves diagnostic accuracy in early PPID cases. This study documents both test results and clinical signs associated with the transition from subclinical to clinical PPID, so that we are better able to recognize potential early PPID, as well as interpret results in these horses. Abstract Poor recognition of subtle clinical abnormalities and equivocal ACTH concentrations make early diagnosis of PPID difficult. Progressive clinical findings and corresponding ACTH concentrations in horses transitioning to PPID over time have not been documented. Seven horses with ACTH concentrations equivocal for PPID (utilizing locally derived, seasonally adjusted diagnostic-cut off values (DCOV)) and no clinical signs of PPID were selected. Sequential measurement of basal and thyrotropin-releasing hormone (TRH)-stimulated ACTH concentrations and recording of clinical findings occurred from October 2017 to November 2021 in a prospective case series. In two horses, marked hypertrichosis developed. Although 1/11 basal ACTH concentrations were below DCOV in 2018, subsequently all basal ACTH concentrations in these two horses without treatment were greater than DCOV. One horse was treated with pergolide which normalized basal ACTH concentrations. Four horses developed intermittent, mild hypertrichosis, and one horse never developed hypertrichosis. Basal ACTH concentrations in these five horses were greater than DCOV in 63/133 (47.4%) of testing points. TRH-stimulated ACTH concentrations in these five horses were greater than DCOV in 77/133 (57.9%) of testing points, sometimes markedly increased and greater than the assay upper limit of detection (LoD) of 1250pg/mL. TRH-stimulated ACTH concentrations were most frequently positive in late summer and early autumn, with 24/37 (64.9%) of TRH-stimulated ACTH concentrations greater than the DCOV in February and March. Horses transitioning to PPID can have subtle clinical signs and equivocal ACTH concentrations. However, TRH-stimulated ACTH concentrations can be markedly greater than DCOV, especially in late summer and early autumn (February and March) allowing for identification of subclinical and transitional cases.
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Affiliation(s)
- Naomi C. Kirkwood
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Kristopher J. Hughes
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Allison J. Stewart
- School of Veterinary Science, Gatton Campus, The University of Queensland, Gatton, QLD 4343, Australia
- Correspondence: ; Tel.: +61-754-601-799
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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: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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Abstract
Equine obesity is common, reducing quality of life and requiring dietary energy restriction. Equine obesity is identified using subjective body condition scoring. Considerations are given for life stage and health status when managing obese equines. Every effort should be made to maximize feeding duration, and minimize time spent without feed while meeting all essential nutrient requirements. Limiting total daily dry matter intake to 2% of current bodyweight per day of a low caloric, forage-based diet may result in adequate body weight loss. Weight loss and weight management plans should be monitored for success and potential gastrointestinal, metabolic, and/or behavioral complications.
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Bamford NJ, Harris PA, Bailey SR. Circannual variation in plasma adrenocorticotropic hormone concentrations and dexamethasone suppression test results in Standardbred horses, Andalusian horses and mixed-breed ponies. Aust Vet J 2020; 98:616-621. [PMID: 33001453 DOI: 10.1111/avj.13022] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/18/2020] [Accepted: 09/04/2020] [Indexed: 01/23/2023]
Abstract
OBJECTIVE To compare circannual plasma concentrations of adrenocorticotropic hormone (ACTH) and seasonal dexamethasone suppression test (DST) results between three different equine breed groups. METHODS Six Standardbred horses, six Andalusian horses and six mixed-breed ponies were followed over a 1-year period, during which time groups were managed identically. Blood samples were collected monthly (around the autumn equinox) or in every second month (other times of the year) for the determination of plasma ACTH concentrations using a chemiluminescent immunoassay. Overnight DSTs were performed quarterly, with suppression of plasma cortisol to below 27 nmol/L at 19 h considered a normal result. RESULTS Seasonal variation in plasma ACTH concentrations was present among all breed groups with, as expected, higher levels detected around the autumn equinox, from February to April (P < 0.001). Plasma ACTH concentrations were different between breed groups in March, with higher levels in Andalusians compared with Standardbreds (P = 0.048) and in ponies compared with Standardbreds (P = 0.010). Suppression of cortisol during the DST was normal for all animals in winter, spring and summer, but five Andalusians and three ponies returned abnormally high results in autumn, compared with zero Standardbreds. CONCLUSION Higher plasma ACTH concentrations and more false-positive DST results were obtained during autumn in ponies and Andalusian horses when compared with Standardbred horses. Potential differences between breeds should be considered when interpreting test results for horses and ponies that are evaluated for pituitary pars intermedia dysfunction. Further work is recommended to establish population-based reference intervals and clinical cut-off values for ACTH in different equine breeds.
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Affiliation(s)
- N J Bamford
- Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - P A Harris
- Equine Studies Group, WALTHAM Petcare Science Institute, Melton Mowbray, Leicestershire, UK
| | - S R Bailey
- Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
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Fortin JS, Benskey MJ, Lookingland KJ, Patterson JS, Howey EB, Goudreau JL, Schott HC. Restoring pars intermedia dopamine concentrations and tyrosine hydroxylase expression levels with pergolide: evidence from horses with pituitary pars intermedia dysfunction. BMC Vet Res 2020; 16:356. [PMID: 32977825 PMCID: PMC7517620 DOI: 10.1186/s12917-020-02565-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/11/2020] [Indexed: 12/20/2022] Open
Abstract
Background Pituitary pars intermedia dysfunction (PPID) develops slowly in aged horses as degeneration of hypothalamic dopaminergic neurons leads to proliferation of pars intermedia (PI) melanotropes through hyperplasia and adenoma formation. Dopamine (DA) concentrations and tyrosine hydroxylase (TH) immunoreactivity are markedly reduced in PI tissue of PPID-affected equids and treatment with the DA receptor agonist pergolide results in notable clinical improvement. Thus, we hypothesized that pergolide treatment of PPID-affected horses would result in greater DA and TH levels in PI tissue collected from PPID-affected horses versus untreated PPID-affected horses. To test this hypothesis, pituitary glands were removed from 18 horses: four untreated PPID-affected horses, four aged and four young horses without signs of PPID, and six PPID-affected horses that had been treated with pergolide at 2 µg/kg orally once daily for 6 months. DA concentrations and TH expression levels in PI tissues were determined by high performance liquid chromatography with electrochemical detection and Western blot analyses, respectively. Results DA and TH levels were lowest in PI collected from untreated PPID-affected horses while levels in the pergolide treated horses were similar to those of aged horses without signs of PPID. Conclusions These findings provide evidence of restoration of DA and TH levels following treatment with pergolide. Equine PPID is a potential animal model of dopaminergic neurodegeneration, which could provide insight into human neurodegenerative diseases.
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Affiliation(s)
- Jessica S Fortin
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, 48824, MI, USA.
| | - Matthew J Benskey
- Department of Pharmacology and Toxicology, Neuroscience Program, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Keith J Lookingland
- Department of Pharmacology and Toxicology, Neuroscience Program, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Jon S Patterson
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, 48824, MI, USA
| | - Erin B Howey
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, 48824, MI, USA
| | - John L Goudreau
- Department of Pharmacology and Toxicology, Neuroscience Program, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA.,Neurology and Ophthalmology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Harold C Schott
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, MI, 48824, USA.
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Mendoza FJ, Toribio RE, Perez-Ecija A. Metabolic and Endocrine Disorders in Donkeys. Vet Clin North Am Equine Pract 2019; 35:399-417. [PMID: 31587976 DOI: 10.1016/j.cveq.2019.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The donkey evolved under harsh and arid environmental conditions, developing unique energy-efficiency traits, with an efficiency to rapidly mobilize fat in situations of increased energy demands or when food is scarce. This evolution has led to an inherent predisposition of donkeys to obesity, dyslipidemias, insulin dysregulation/metabolic syndrome, pituitary pars intermedia dysfunction, and endocrinopathic laminitis. Marked differences have been described in hormone dynamics and testing protocols for the diagnosis of these endocrine and metabolic diseases in donkeys compared with horses, underlining the necessity of a species-specific approach in order to avoid misdiagnosis, unnecessary or inadequate treatments, and additional costs.
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Affiliation(s)
- Francisco J Mendoza
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Rabanales, Road Madrid-Cadiz km 396, Cordoba 14014, Spain.
| | - Ramiro E Toribio
- Department of Veterinary Clinical Sciences, The Ohio State University, 601 Vernon Tharp Street, Columbus, OH 43210, USA
| | - Alejandro Perez-Ecija
- Department of Animal Medicine and Surgery, University of Cordoba, Campus Rabanales, Road Madrid-Cadiz km 396, Cordoba 14014, Spain
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McFarlane D. Diagnostic Testing for Equine Endocrine Diseases: Confirmation Versus Confusion. Vet Clin North Am Equine Pract 2019; 35:327-338. [PMID: 31076223 DOI: 10.1016/j.cveq.2019.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Despite there being only 2 common endocrine diseases in horses, pituitary pars intermedia dysfunction (PPID) and equine metabolic syndrome (EMS), diagnosis is still confusing. Failing to consider horse factors and treating based on laboratory results only have caused many animals to receive lifelong drug treatment unnecessarily. Increased plasma ACTH, baseline or TRH stimulated, supports a diagnosis of PPID; however, breed, age, thriftiness, illness, coat color, geography, diet, and season also affect ACTH concentration. Insulin dysregulation, the hallmark of EMS, can result from insulin resistance or excessive postprandial insulin release. Each requires a different diagnostic test to reach a diagnosis.
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Affiliation(s)
- Dianne McFarlane
- Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, 264 McElroy Hall, CVHS-OSU, Stillwater, OK 74078, USA.
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Affiliation(s)
- C. J. Scott
- Rossdales Veterinary Surgeons Beaufort Cottage Stables Newmarket Suffolk UK
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Mendoza FJ, Toribio RE, Perez-Ecija A. Donkey Internal Medicine—Part I: Metabolic, Endocrine, and Alimentary Tract Disturbances. J Equine Vet Sci 2018. [PMCID: PMC7111315 DOI: 10.1016/j.jevs.2018.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolic and endocrine disturbances are common in donkeys. This species has an inherent ability to thrive with limited and poor-quality roughage. Donkeys are extremely efficient in energy storage and mobilization, which predisposes to hyperlipemia, obesity, and metabolic syndrome. The prevalence of dyslipidemias is higher in donkeys than other equids, which is more evident under stressful conditions. Diagnosis of endocrine and metabolic disorders in donkeys should be based on species-specific information considering that differences in a multitude of variables compared with horses have been demonstrated. Protocols to assess endocrine disorders (e.g., pituitary pars intermedia dysfunction, metabolic syndrome, and thyroid illness) are unavailable, and extrapolation from horse data can be misleading. Treatment guidelines for these conditions in donkeys are currently not reported. On the other hand, the typical stoic and hardy behavior of donkeys can hinder prompt diagnosis of gastrointestinal problems, specifically colic, which is commonly caused by dental issues in this species. Moreover, subclinical gastric ulcer syndrome appears to be a common pathology in this species, especially in working donkeys. Donkeys are different to horses. Numerous physiological and clinic-pathologic idiosyncrasies are reported in horses. Data published for horses should not be extrapolated for donkeys. Specific reference ranges, doses, and protocols have to be used for donkeys.
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Affiliation(s)
- Francisco J. Mendoza
- Departamento de Medicina y Cirugia Animal, Universidad de Cordoba, Campus Rabanales, Cordoba, Spain
- Corresponding author at: Dr Francisco J. Mendoza, Department of Animal Medicine and Surgery University of Cordoba, 14014 Cordoba, Spain.
| | - Ramiro E. Toribio
- Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH
| | - Alejandro Perez-Ecija
- Departamento de Medicina y Cirugia Animal, Universidad de Cordoba, Campus Rabanales, Cordoba, Spain
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Christen G, Gerber V, van der Kolk JH, Frey CF, Fouché N. Fecal strongyle egg counts in horses with suspected pre-clinical pituitary pars intermedia dysfunction before and after treatment with pergolide. Vet J 2018; 235:60-62. [DOI: 10.1016/j.tvjl.2018.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 03/13/2018] [Accepted: 03/21/2018] [Indexed: 10/17/2022]
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Raftery AG, Berman KG, Sutton DGM. Severe eosinophilic cholangiohepatitis due to fluke infestation in a pony in Scotland. EQUINE VET EDUC 2015. [DOI: 10.1111/eve.12470] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- A. G. Raftery
- Weipers Centre Equine Hospital; University of Glasgow; UK
| | - K. G. Berman
- Department of Pathology; University of Glasgow; UK
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Neutrophil function in healthy aged horses and horses with pituitary dysfunction. Vet Immunol Immunopathol 2015; 165:99-106. [PMID: 25962580 DOI: 10.1016/j.vetimm.2015.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/01/2015] [Accepted: 04/23/2015] [Indexed: 11/23/2022]
Abstract
Immunosuppression leading to opportunist bacterial infection is a well-recognized sequela of equine pituitary pars intermedia dysfunction (PPID). The mechanisms responsible for immune dysfunction in PPID however, are as of yet poorly characterized. Horses with PPID have high concentrations of hormones known to impact immune function including α-melanocyte stimulating hormone (α-MSH) and insulin. α-MSH and related melanocortins have been shown in rodents and people to impair neutrophil function by decreasing superoxide production (known as oxidative burst activity), migration and adhesion. The goal of this study was to determine if neutrophil function is impaired in horses with PPID and, if so, to determine if plasma α-MSH or insulin concentration correlated with the severity of neutrophil dysfunction. Specifically, neutrophil phagocytosis, oxidative burst activity, chemotaxis and adhesion were assessed. Results of this study indicate that horses with PPID have reduced neutrophil function, characterized by decreased oxidative burst activity and adhesion. In addition, chemotaxis was greater in healthy aged horses than in young horses or aged horses with PPID. Plasma insulin: α-MSH ratio, but not individual hormone concentration was correlated to neutrophil oxidative burst activity. In summary, neutrophil function is impaired in horses with PPID, likely due to altered hormone concentrations and may contribute to increased risk of opportunistic infections. Whether regulation of hormone concentration profiles in horses with PPID using therapeutic intervention improves neutrophil function and reduces infections needs to be explored.
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