Vasorelaxation responses to insulin in laminar vessel rings from healthy, lean horses.
Abstract: Hyperinsulinemia causes laminitis experimentally and is a risk factor for naturally occurring laminitis. The aim of this study was to investigate the effects of insulin on laminar vascular relaxation and to induce insulin-associated vascular dysfunction in vitro. Relaxation responses of isolated laminar arterial and venous rings to acetylcholine and insulin were evaluated. To alter vascular function in response to insulin, all vessel rings were incubated with insulin or vehicle, submaximally contracted, administered insulin again and relaxation responses recorded. Laminar arteries were also incubated with the mitogen-activated protein kinase (MAPK) inhibitor, PD-98059. Relaxation in response to acetylcholine was not different between arteries and veins, but veins relaxed less in response to insulin than arteries. In arteries incubated with insulin, the subsequent relaxation response to insulin was blunted. Veins had minimal relaxation to insulin regardless of incubation. Arteries incubated with PD-98059 relaxed more in response to insulin than arteries not exposed to PD-98059, indicating that MAPK plays a role in maintenance of basal tone in laminar arteries. A differing response of laminar veins and arteries to insulin-induced relaxation may be important in understanding the link between hyperinsulinemia and laminitis. In vitro induction of vascular dysfunction in response to insulin in laminar arteries may be useful for testing therapeutic interventions and for understanding the pathophysiology of laminitis.
Copyright © 2014 Elsevier Ltd. All rights reserved.
Publication Date: 2014-07-29 PubMed ID: 25155219DOI: 10.1016/j.tvjl.2014.07.021Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research paper studies the effects of insulin on the relaxation of blood vessels in the lamina (part of the hoof) of healthy horses and investigates the use of in vitro methods to induce insulin-related vascular dysfunction. The study also highlights the role of mitogen-activated protein kinase (MAPK) in maintaining basal tone in laminar arteries and suggests potential differences in how veins and arteries respond to insulin, which could provide insight into understanding the association between high insulin levels and laminitis.
Research Objective and Methodology
- The research aimed to understand the impact of insulin on the relaxation of blood vessels in horse hooves, a condition called laminitis, which is experimentally induced by hyperinsulinemia and recognized as a risk in natural occurrences of the disease.
- To achieve this, the research team evaluated the relaxation responses of isolated laminar arterial and venous rings to insulin and acetylcholine.
- The team also used insulin or another substance (referred to as a vehicle) to induce variations in vascular function, measuring relaxation responses before and after the administration of insulin.
Insulin Impact and Role of MAPK
- The results showed that while there was no apparent difference in relaxation in response to acetylcholine between arteries and veins, veins reacted differently to insulin, showing less relaxation compared to arteries.
- The induction of insulin in arteries led to a diminished relaxation response to further insulin administration.
- On the other hand, the response of veins to insulin was minimal regardless of induction.
- When laminar arteries were treated with PD-98059, a MAPK inhibitor, they exhibited more relaxation in response to insulin as compared to arteries not exposed to it. This implies that MAPK has a role in maintaining basal tone in laminar arteries.
Implications and Conclusions
- The research suggests that differing responses of laminar veins and arteries to insulin-induced relaxation could be crucial in understanding the relationship between hyperinsulinemia and laminitis.
- The induction of vascular dysfunction in response to insulin in laminar arteries, if done in vitro, could be valuable for testing possible treatments and for comprehending the pathophysiology of laminitis.
Cite This Article
APA
Wooldridge AA, Waguespack RW, Schwartz DD, Venugopal CS, Eades SC, Beadle RE.
(2014).
Vasorelaxation responses to insulin in laminar vessel rings from healthy, lean horses.
Vet J, 202(1), 83-88.
https://doi.org/10.1016/j.tvjl.2014.07.021 Publication
Researcher Affiliations
- Department of Clinical Sciences, Auburn University College of Veterinary Medicine, 1500 Wire Road, Auburn, Alabama 36849, USA. Electronic address: aaw0002@auburn.edu.
- Southeastern Veterinary Surgery Center, 3576 Macon Rd., Columbus, Georgia 31907, USA.
- Department of Anatomy, Physiology, and Pharmacology, Auburn University College of Veterinary Medicine, 1500 Wire Road, Auburn, Alabama 36849, USA.
- Equine Health Studies Program, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana 70803, USA.
- Equine Health Studies Program, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana 70803, USA.
- Equine Health Studies Program, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana 70803, USA.
MeSH Terms
- Acetylcholine / pharmacology
- Animals
- Blood Vessels / drug effects
- Female
- Flavonoids / pharmacology
- Foot / blood supply
- Horses
- Insulin / pharmacology
- Male
- Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors
- Tissue Culture Techniques
- Vasodilation / drug effects
- Vasodilator Agents / pharmacology
Citations
This article has been cited 3 times.- Durham AE, Frank N, McGowan CM, Menzies-Gow NJ, Roelfsema E, Vervuert I, Feige K, Fey K. ECEIM consensus statement on equine metabolic syndrome.. J Vet Intern Med 2019 Mar;33(2):335-349.
- Nostell KE, Lindåse SS, Bröjer JT. Blood pressure in Warmblood horses before and during a euglycemic-hyperinsulinemic clamp.. Acta Vet Scand 2016 Oct 20;58(Suppl 1):65.
- Morgan RA, Keen JA, Walker BR, Hadoke PW. Vascular Dysfunction in Horses with Endocrinopathic Laminitis.. PLoS One 2016;11(9):e0163815.
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