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Rieger J, Kaessmeyer S, Al Masri S, Hünigen H, Plendl J. Endothelial cells and angiogenesis in the horse in health and disease-A review. Anat Histol Embryol 2020; 49:656-678. [PMID: 32639627 DOI: 10.1111/ahe.12588] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 04/04/2020] [Accepted: 06/01/2020] [Indexed: 12/15/2022]
Abstract
The cardiovascular system is the first functional organ in the embryo, and its blood vessels form a widespread conductive network within the organism. Blood vessels develop de novo, by the differentiation of endothelial progenitor cells (vasculogenesis) or by angiogenesis, which is the formation of new blood vessels from existing ones. This review presents an overview of the current knowledge on physiological and pathological angiogenesis in the horse including studies on equine endothelial cells. Principal study fields in equine angiogenesis research were identified: equine endothelial progenitor cells; equine endothelial cells and angiogenesis (heterogeneity, markers and assessment); endothelial regulatory molecules in equine angiogenesis; angiogenesis research in equine reproduction (ovary, uterus, placenta and conceptus, testis); angiogenesis research in pathological conditions (tumours, ocular pathologies, equine wound healing, musculoskeletal system and laminitis). The review also includes a table that summarizes in vitro studies on equine endothelial cells, either describing the isolation procedure or using previously isolated endothelial cells. A particular challenge of the review was that results published are fragmentary and sometimes even contradictory, raising more questions than they answer. In conclusion, angiogenesis is a major factor in several diseases frequently occurring in horses, but relatively few studies focus on angiogenesis in the horse. The challenge for the future is therefore to continue exploring new therapeutic angiogenesis strategies for horses to fill in the missing pieces of the puzzle.
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Affiliation(s)
- Juliane Rieger
- Department of Veterinary Medicine, Institute for Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany
| | - Sabine Kaessmeyer
- Department of Veterinary Medicine, Institute for Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany
| | - Salah Al Masri
- Department of Veterinary Medicine, Institute for Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany
| | - Hana Hünigen
- Department of Veterinary Medicine, Institute for Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany
| | - Johanna Plendl
- Department of Veterinary Medicine, Institute for Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany
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Stokes SM, Bertin FR, Stefanovski D, Belknap JK, Medina-Torres CE, Pollitt CC, van Eps AW. Lamellar energy metabolism and perfusion in the euglycaemic hyperinsulinaemic clamp model of equine laminitis. Equine Vet J 2020; 52:577-584. [PMID: 31845378 DOI: 10.1111/evj.13224] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/29/2019] [Accepted: 12/04/2019] [Indexed: 01/19/2023]
Abstract
BACKGROUND Hyperinsulinaemia is associated with the development of endocrinopathic laminitis; however, the mechanisms remain unclear. OBJECTIVES Evaluate the effects of hyperinsulinaemia on lamellar energy metabolism and perfusion during laminitis development. STUDY DESIGN In vivo experiment. METHODS Eight Standardbred horses were instrumented with a microdialysis probe in the lamellae of a forelimb. A 24 hours baseline period (BASELINE) was followed by 48 hours of a continuous euglycaemic hyperinsulinaemic clamp (EHC) from 24 to 72 hours (CLAMP). Microdialysate was collected every 6 hours and analysed for glucose, lactate and pyruvate concentrations and lactate-to-pyruvate ratio (L:P). Microdialysis urea clearance was used to estimate lamellar tissue perfusion. Archived microdialysis samples from six identically instrumented Standardbred horses served as controls (CON). Variables were compared over time and between EHC and CON horses using a mixed-effects linear regression model. RESULTS Glucose concentration decreased during the CLAMP period in CON and EHC horses (P < .001), but there was no difference between CON and EHC (P > .9). Lactate concentration increased during the CLAMP period in CON and EHC horses (P < .001), however, the rate of increase was significantly higher in EHC horses relative to CON (P = .014). There was a relative increase in pyruvate concentration in EHC horses compared with CON during the CLAMP period (P = .03). L:P increased significantly in CON horses during the CLAMP period (P < .001) but not in EHC (P = .1). Urea clearance did not change in CON (P = .9) or EHC (P = .05) during the CLAMP, but did increase in EHC relative to CON (P = .02). MAIN LIMITATIONS The effects of microdialysis probe implantation on perfusion and metabolism remain unclear. The EHC model may not mimic natural endocrinopathic laminitis. CONCLUSIONS Laminitis developed without evidence of lamellar hypoperfusion or energy stress. Therapies to improve perfusion are unlikely to affect the initial development of endocrinopathic laminitis.
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Affiliation(s)
- Simon M Stokes
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Francois R Bertin
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Darko Stefanovski
- New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania
| | - James K Belknap
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Carlos E Medina-Torres
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Christopher C Pollitt
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia
| | - Andrew W van Eps
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia.,New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania
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Zizzadoro C, Caruso M, Punzi S, Crescenzo G, Zongoli F, Belloli C. A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators. J Vet Pharmacol Ther 2017; 41:51-59. [DOI: 10.1111/jvp.12436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 06/07/2017] [Indexed: 01/17/2023]
Affiliation(s)
- C. Zizzadoro
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | - M. Caruso
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | - S. Punzi
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | - G. Crescenzo
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | | | - C. Belloli
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
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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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Harfoush K, Guintard C, Desfontis JC, Thorin C, Douart C, Mallem MY, Betti E. Venous Valvular Distribution in the Thoracic and Pelvic Limbs of the Horse. Anat Histol Embryol 2015; 45:409-417. [DOI: 10.1111/ahe.12209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/21/2015] [Indexed: 11/27/2022]
Affiliation(s)
- K. Harfoush
- Unité d'Anatomie Comparée; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
- UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
| | - C. Guintard
- Unité d'Anatomie Comparée; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
| | - J. C. Desfontis
- UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
| | - C. Thorin
- UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
| | - C. Douart
- Unité d'Anatomie Comparée; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
| | - M. Y. Mallem
- UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
| | - E. Betti
- Unité d'Anatomie Comparée; Ecole Nationale Vétérinaire; Agroalimentaire et de l'Alimentation Nantes-Atlantique - Oniris; BP 40706 44307 Nantes France
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Gauff FC, Patan-Zugaj B, Licka TF. Effect of short-term hyperinsulinemia on the localization and expression of endothelin receptors A and B in lamellar tissue of the forelimbs of horses. Am J Vet Res 2014; 75:367-74. [PMID: 24669922 DOI: 10.2460/ajvr.75.4.367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To determine the effect of short-term hyperinsulinemia on the localization and expression of endothelin receptor (ETR)-A and ETR-B in lamellar tissue of the forelimbs of horses. SAMPLES Distal portion of 15 cadaveric forelimbs from healthy adult horses (1 limb/horse) obtained immediately after slaughter at an abattoir. PROCEDURES Each forelimb was assigned to 1 of 3 treatment groups (perfused with autologous blood for 10 hours [control perfusion; n = 5], perfused with an insulin [142 ± 81 μU/mL] perfusate for 10 hours [insulinemic perfusion; 5], or not perfused [unperfused control; 5]). Immunohistochemical evaluation of lamellar tissue was performed to assess localization of ETR-A and ETR-B. Expression of ETR-A and ETR-B was measured semiquantitatively on a scale of 0 to 3 (0 = none, 1 = mild, 2 = moderate, and 3 = high-intensity staining) and quantitatively by means of gray value analysis with imaging software. RESULTS In all specimens, ETR-A and ETR-B were localized in endothelium, smooth muscle cells, axons, and keratinocytes. Quantitative expression of ETR-A in the midportion of the primary epidermal lamellae for the insulinemic perfusion group (149 ± 16) was lower than that for the control perfusion group (158 ± 15). Expression of ETR-B in the primary epidermal lamellae tips for the insulinemic perfusion group (140 ± 29) was higher than that for the control perfusion group (114 ± 8). CONCLUSIONS AND CLINICAL RELEVANCE Hyperinsulinemia caused significant changes in endothelin receptor expression, which suggested that ETR antagonists might be beneficial for treatment of laminitis in horses.
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Affiliation(s)
- Felicia C Gauff
- Department of Horses and Small Animals, University of Veterinary Medicine Vienna, A-1210 Vienna, Austria
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Venugopal C, Holmes E, Beadle R, Kearney M, Eades S. Comparison of Insulin-Induced Digital Vessel Ring Responses of Laminitic and Clinically Healthy Horses. J Equine Vet Sci 2014. [DOI: 10.1016/j.jevs.2014.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Wooldridge AA, Waguespack RW, Schwartz DD, Venugopal CS, Eades SC, Beadle RE. Vasorelaxation responses to insulin in laminar vessel rings from healthy, lean horses. Vet J 2014; 202:83-8. [PMID: 25155219 DOI: 10.1016/j.tvjl.2014.07.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 07/21/2014] [Accepted: 07/25/2014] [Indexed: 10/25/2022]
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.
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Affiliation(s)
- A A Wooldridge
- Department of Clinical Sciences, Auburn University College of Veterinary Medicine, 1500 Wire Road, Auburn, Alabama 36849, USA.
| | - R W Waguespack
- Southeastern Veterinary Surgery Center, 3576 Macon Rd., Columbus, Georgia 31907, USA
| | - D D Schwartz
- Department of Anatomy, Physiology, and Pharmacology, Auburn University College of Veterinary Medicine, 1500 Wire Road, Auburn, Alabama 36849, USA
| | - C S Venugopal
- Equine Health Studies Program, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana 70803, USA
| | - S C Eades
- Equine Health Studies Program, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana 70803, USA
| | - R E Beadle
- Equine Health Studies Program, Louisiana State University School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana 70803, USA
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Lapo RA, Gogny M, Chatagnon G, Lalanne V, Harfoush K, Assane M, Desfontis JC, Mallem MY. Equine digital veins are more sensitive to superoxide anions than digital arteries. Eur J Pharmacol 2014; 740:66-71. [PMID: 25014758 DOI: 10.1016/j.ejphar.2014.06.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 11/24/2022]
Abstract
This work was designed to investigate (i) the effect of superoxide dismutase (SOD) inhibition on endothelial function and (ii) the free radical-induced endothelial dysfunction in equine digital veins (EDVs) and equine digital arteries (EDAs) isolated from healthy horses. EDV and EDA rings were suspended in a 5 ml organ bath containing Krebs solution. After a 60 min equilibration period, EDV and EDA rings were contracted with phenylephrine. Then, cumulative concentration-response curves (CCRCs) to acetylcholine were performed. In both EDVs and EDAs, acetylcholine (1 nM to 10 µM) produced concentration-dependent relaxation. We investigated the influence of SOD inhibition by diethyldithiocarbamate (DETC; 100 µM), a CuZnSOD inhibitor, on EDAs and EDVs relaxant responses to acetylcholine. Acetylcholine -mediated relaxation was impaired by DETC only in EDVs. SOD activity assayed by a xanthine-xanthine oxidase method was higher in EDAs compared with EDVs (P<0.05). CCRCs to acetylcholine established in the presence of pyrogallol (30 µM) or homocysteine (20 µM), two superoxide anions generating systems showed that in both EDVs and EDAs, the acetylcholine-mediated relaxation was significantly impaired by pyrogallol and homocysteine. This impairment was more pronounced in EDVs than in EDAs. Moreover, the pyrogallol-induced impairment of acetylcholine-mediated relaxation was potentiated by DETC to a greater extent in EDVs. We concluded that due to the lower activity of SOD, EDVs are more sensitive to superoxide anions than EDAs. So, any alteration of superoxide anions metabolism is likely to have a more important impact on venous rather than arterial relaxation.
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Affiliation(s)
- Rock Allister Lapo
- Ecole Inter-états des Sciences et Médecine Vétérinaires BP 5077 Dakar, Senegal
| | - Marc Gogny
- LUNAM Université, Oniris, UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle, Atlanpole La Chantrerie, BP 40706, Nantes F-44307, France
| | - Gérard Chatagnon
- LUNAM Université, Oniris, Unité de Sécurité Sanitaire des Biotechnologies de la Reproduction, Atlanpole La Chantrerie, BP 40706, Nantes, F-44307, France
| | - Valérie Lalanne
- LUNAM Université, Oniris, UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle, Atlanpole La Chantrerie, BP 40706, Nantes F-44307, France
| | - Khaled Harfoush
- LUNAM Université, Oniris, UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle, Atlanpole La Chantrerie, BP 40706, Nantes F-44307, France
| | - Moussa Assane
- Ecole Inter-états des Sciences et Médecine Vétérinaires BP 5077 Dakar, Senegal
| | - Jean-Claude Desfontis
- LUNAM Université, Oniris, UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle, Atlanpole La Chantrerie, BP 40706, Nantes F-44307, France
| | - Mohamed Yassine Mallem
- LUNAM Université, Oniris, UPSP 5304 de Physiopathologie Animale et Pharmacologie Fonctionnelle, Atlanpole La Chantrerie, BP 40706, Nantes F-44307, France.
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The effect of tumour necrosis factor-α and insulin on equine digital blood vessel function in vitro. Inflamm Res 2014; 63:637-47. [PMID: 24764104 DOI: 10.1007/s00011-014-0736-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/21/2014] [Accepted: 04/08/2014] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVE AND DESIGN Insulin and inflammatory cytokines may be involved in equine laminitis, which might be associated with digital vascular dysfunction. This study determined the effects of TNF-α and insulin on the endothelial-dependent relaxant responses of equine digital blood vessels and on equine digital vein endothelial cell (EDVEC) cGMP production. MATERIAL Isolated rings of equine digital arteries (EDAs) and veins (EDVs) were obtained and EDVECs were cultured from horses euthanized at an abattoir. METHODS The effect of incubation with TNF-α (10 ng/ml) and/or insulin (1,000 μIU/ml) for 1.5 h or overnight under hyperoxic and hypoxic conditions on carbachol (endothelium-dependent) induced relaxation was assessed. The time course and concentration dependency of the effect of TNF-α and the effect of insulin (1,000 μIU/ml) on EDVEC cGMP production was determined. RESULTS Incubation of EDAs overnight with TNF-α under hypoxic conditions resulted in endothelial-dependent vascular dysfunction. EDVs produced a more variable response. TNF-α increased EDVEC cGMP formation in a time- and concentration-dependent manner. Insulin had no significant effects. CONCLUSIONS There is a mismatch between the results obtained from isolated vessel rings and cultured endothelial cells suggesting TNF-α may reduce the biological effect of NO by reducing its bioavailability rather than its formation, leading to endothelial cell dysregulation.
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Douthit TL, Bormann JM, Bello NM. Assessing the Association Between Hoof Thermography and Hoof Doppler Ultrasonography for the Diagnosis of Lameness in Horses. J Equine Vet Sci 2014. [DOI: 10.1016/j.jevs.2013.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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12
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Kabbesh N, Gogny M, Chatagnon G, Noireaud J, Desfontis JC, Mallem MY. Vasorelaxant effect of propentofylline in isolated equine digital veins. Eur J Pharmacol 2013; 718:124-30. [PMID: 24051271 DOI: 10.1016/j.ejphar.2013.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 08/26/2013] [Accepted: 09/04/2013] [Indexed: 11/26/2022]
Abstract
We evaluated the vasorelaxant effect of propentofylline (PPF), a methylxanthine derivative, and its mechanism of action in equine digital veins (EDVs). Cumulative concentration-response curves to PPF (1 nM-300 µM) were recorded in phenylephrine-precontracted EDV rings under different experimental conditions. PPF-induced relaxation was partially inhibited by endothelium removal, but was unaltered by CGS-15943 (an adenosine receptor antagonist; 3 µM). PPF-induced relaxation was partially inhibited in the presence of L-NAME (a nitric oxide (NO) synthase inhibitor; 100 µM), ODQ (an inhibitor of soluble guanylyl cyclase; 30 µM) or Rp-8-Br-PET-cGMP-S (a protein kinase G inhibitor; 3 µM). It was not modified by indomethacin (a non-selective cyclooxygenase (COX) inhibitor; 10 µM), and was slightly potentiated by H-89 (a protein kinase A inhibitor; 2 µM). In endothelium-intact EDVs, PPF-induced relaxation was associated with a 2.4- and 24.1-fold increase in the tissue cGMP and cAMP content respectively. PPF (100 μM) did not shift the concentration-response curve to phenylephrine (1 nM-300 µM) but reduced the maximal effect. To investigate whether PPF can affect cAMP- and cGMP-induced relaxations, relaxation curves to forskolin (an activator of adenylate cyclase) and to sodium nitroprusside (SNP, a NO donor) were recorded in EDV rings pretreated with PPF (100 µM). PPF only slightly potentiated the forskolin-induced relaxation without affecting the SNP-induced relaxation. We demonstrated that PPF-induced relaxation in EDVs is partially endothelium-dependent. The PPF-induced relaxation partially occurred via NO release and both cAMP and cGMP generation, through COX-independent mechanisms but could also result from the inhibition of cAMP-phosphodiesterase activity for the highest concentrations.
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Affiliation(s)
- Nasr Kabbesh
- LUNAM Université Oniris, "UPSP 5304 de physiopathologie animale et de pharmacologie fonctionnelle", Atlanpole-La Chantrerie, BP 40706, Nantes F-44307, France
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Expression of purinergic P2X receptor subtypes 1, 2, 3 and 7 in equine laminitis. Vet J 2013; 198:472-8. [PMID: 24080476 DOI: 10.1016/j.tvjl.2013.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 08/09/2013] [Accepted: 08/12/2013] [Indexed: 12/13/2022]
Abstract
Tissue sensitisation and chronic pain have been described in chronic-active laminitis in the horse, making treatment of such cases difficult. Purinergic P2X receptors are linked to chronic pain and inflammation. The aim of this study was to examine the expression of purinergic P2X receptor subtypes 1, 2, 3 and 7 in the hoof, palmar digital vessels and nerve, dorsal root ganglia and spinal cord in horses with chronic-active laminitis (n=5) compared to non-laminitic horses (n=5). Immunohistochemical analysis was performed on tissue sections using antibodies against P2X receptor subtypes 1-3 and 7. In horses with laminitis, there was a reduction in the thickness of the tunica media layer of the palmar digital vein as a proportion of the whole vessel diameter (0.48±0.05) compared to the non-laminitic group (0.57±0.04; P=0.02). P2X receptor subtype 3 was expressed in the smooth muscle layer (tunica media) of the palmar digital artery of horses with laminitis, but was absent in horses without laminitis. There was strong expression of P2X receptor subtype 7 in the proliferating, partially keratinised, epidermal cells of the secondary epidermal lamellae in the hooves of horses with laminitis, but no immunopositivity in horses without laminitis.
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Katz LM, Bailey SR. A review of recent advances and current hypotheses on the pathogenesis of acute laminitis. Equine Vet J 2013; 44:752-61. [PMID: 23106629 DOI: 10.1111/j.2042-3306.2012.00664.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With the increasing number of studies being published on the different experimental models used to induce and study acute laminitis, the pathophysiological events associated with these various models (i.e. starch overload, oligofructose overload, black walnut extract and hyperinsulinaemia) can be compared more realistically. Within this review, the mechanisms for metabolic vs. inflammatory laminitis are discussed, and the question of how pasture laminitis may fit into any of the proposed mechanisms is addressed.
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Affiliation(s)
- L M Katz
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland.
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Gauff F, Patan-Zugaj B, Licka TF. Hyperinsulinaemia increases vascular resistance and endothelin-1 expression in the equine digit. Equine Vet J 2013; 45:613-8. [PMID: 23489109 DOI: 10.1111/evj.12040] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 12/05/2012] [Indexed: 11/29/2022]
Abstract
REASONS FOR PERFORMING STUDY Insulin leads to overexpression of endothelin-1 (ET-1) in the endothelium of insulin-resistant rodents. If this is also the case in equine laminar tissue, this could explain the predisposition of insulin-resistant horses to laminitis. OBJECTIVES To investigate the effect of hyperinsulinaemia on metabolism and vascular resistance of the isolated equine digit in a model of extracorporeal perfusion. STUDY DESIGN Randomised, controlled study with interventional group, with blinded evaluation of histology results. METHOD After exsanguination, equine digits (n = 11) and autologous blood were collected at an abattoir. One digit served as a hyperinsulinaemic pilot limb, 5 digits were assigned to the hyperinsulinaemic perfusion (IP) group and 5 to the control perfusion (CP) group. Digits were perfused for 10 h at a defined perfusion rate of 12 ml/min/kg. After the first hour of perfusion (equilibration period), insulin was added to the reservoir of the IP digits. Perfusion pressure, glucose consumption, lactate and lactate dehydrogenase were monitored. Vascular resistance was calculated as perfusion pressure (in millimetres of mercury) in relation to the flow rate (in millilitres per minute). After perfusion, histology samples of the dorsal hoof wall (haematoxylin & eosin or periodic acid-Schiff) were evaluated. Immunohistology with a polyclonal rabbit-derived anti-endothelin antibody was used for detection of ET-1. RESULTS In the IP group, the mean insulin concentration in the plasma of the perfusate was 142 ± 81 μiu/ml, while insulin concentration was <3 μiu/ml in the CP group. Mean vascular resistance was significantly higher (P<0.01) in the IP group (2.04 ± 1.13 mmHg/ml/min) than in the CP group (1.31 ± 0.55 mmHg/ml/min). Histology of the IP group samples showed significantly more vessels with an open lumen, increased width of the secondary epidermal lamellae and formation of oedema. In the lamellar vessels (veins and arteries) and nerve fibres, ET-1 expression was much more prominent in the IP group than in the CP group samples. CONCLUSIONS Short-term hyperinsulinaemia leads to increased vascular resistance in the equine digit and increased expression of ET-1 in the laminar tissue.
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Affiliation(s)
- F Gauff
- Clinic of Orthopaedics in Large Animals, Department of Horses and Small Animals, Vienna University of Veterinary Medicine, Austria.
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Guedes AGP, Morisseau C, Sole A, Soares JHN, Ulu A, Dong H, Hammock BD. Use of a soluble epoxide hydrolase inhibitor as an adjunctive analgesic in a horse with laminitis. Vet Anaesth Analg 2013; 40:440-8. [PMID: 23463912 DOI: 10.1111/vaa.12030] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 06/28/2012] [Indexed: 02/06/2023]
Abstract
HISTORY A 4-year old, 500 kg Thoroughbred female horse diagnosed with bilateral forelimb laminitis and cellulitis on the left forelimb became severely painful and refractory to non-steroidal anti-inflammatory therapy (flunixin meglumine on days 1, 2, 3 and 4; and phenylbutazone on days 5, 6 and 7) alone or in combination with gabapentin (days 6 and 7). PHYSICAL EXAMINATION Pain scores assessed independently by three individuals with a visual analog scale (VAS; 0 = no pain and 10 = worst possible pain) were 8.5 on day 6, and it increased to 9.5 on day 7. Non-invasive blood pressure monitoring revealed severe hypertension. MANAGEMENT As euthanasia was being considered for humane reasons, a decision was made to add an experimental new drug, trans-4-{4-[3-(4-Trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy}-benzoic acid (t-TUCB), which is a soluble epoxide hydrolase (sEH) inhibitor, to the treatment protocol. Dose and frequency of administration were selected based on the drug potency against equine sEH to produce plasma concentrations within the range of 30 nmol L(-1) and 2.5 μmol L(-1) . Pain scores decreased sharply and remarkably following t-TUCB administration and blood pressure progressively decreased to physiologic normal values. Plasma concentrations of t-TUCB, measured daily, were within the expected range, whereas phenylbutazone and gabapentin plasma levels were below the suggested efficacious concentrations. FOLLOW UP No adverse effects were detected on clinical and laboratory examinations during and after t-TUCB administration. No new episodes of laminitis have been noted up to the time of writing (120 days following treatment). CONCLUSIONS Inhibition of sEH with t-TUCB was associated with a significant improvement in pain scores in one horse with laminitis whose pain was refractory to the standard of care therapy. No adverse effects were noticed. Future studies evaluating the analgesic and protective effects of these compounds in painful inflammatory diseases in animals are warranted.
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Affiliation(s)
- Alonso G P Guedes
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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Borer-Weir KE, Bailey SR, Harris PA, Menzies-Gow NJ, Elliott J. Seasonal variation in maintenance of phenylephrine-induced tone in isolated equine digital arteries under hypoxic or hyperoxic conditions in vitro. Res Vet Sci 2013; 94:725-7. [PMID: 23415068 DOI: 10.1016/j.rvsc.2013.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/03/2013] [Accepted: 01/20/2013] [Indexed: 11/27/2022]
Abstract
Digital vasoconstriction, ischaemia and hypoxia may predispose to acute laminitis. Laminitis incidence varies seasonally, peaking in spring and summer. Direct seasonal influences on equine digital artery (EDA) contractility have not been investigated. This study assessed seasonal variation in maintenance of phenylephrine (PHE)-induced tone in isolated EDAs under hypoxic (95% nitrogen) and hyperoxic (95% oxygen) conditions. The objective was to measure change in arterial tone over time after constriction to a plateau with PHE. Tone was measured at plateau and over time and percentage change calculated. Hyperoxic EDAs maintained PHE-induced tone over 1 h with no seasonal variation. Hypoxic EDAs relaxed in fall (median [inter-quartile range] 59% [44-77%] decrease from plateau; P=0.008), contracted in spring (65% [20-192%] increase from plateau; P=0.03) and did not significantly change tone in winter (18% [0-28%] decrease; P=0.13). Continued contraction under hypoxic conditions in spring may contribute to digital vasoconstriction.
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Affiliation(s)
- K E Borer-Weir
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, United Kingdom.
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Reesink HL, Divers TJ, Bookbinder LC, van Eps AW, Soderholm LV, Mohammed HO, Cheetham J. Measurement of digital laminar and venous temperatures as a means of comparing three methods of topically applied cold treatment for digits of horses. Am J Vet Res 2012; 73:860-6. [PMID: 22620701 DOI: 10.2460/ajvr.73.6.860] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare effects of 3 methods of topically applied cold treatment (cryotherapy) on digital laminar and venous temperatures in horses. ANIMALS 9 healthy adult Thoroughbreds. PROCEDURES Thermocouples were placed in palmar digital veins and digital laminae of both forelimbs of horses. Three methods of cryotherapy were applied to the distal aspects of the limbs: wader boot (63-cm-tall vinyl boot filled with ice and water [ice slurry]), ice bag (5-L fluid bag filled with ice slurry), and a gel pack boot (boot containing frozen gel packs). Gel packs and ice slurries were replenished every hour during cryotherapy. The forelimb that received the first treatment was randomly assigned; thereafter, control and treated forelimbs were alternated for each treatment. For each treatment, temperatures were recorded every minute during 15-minute pretreatment, 2-hour treatment, and ≥ 30 minute rewarming periods. Once temperatures had returned to within 3°C below pretreatment values, the experiment was repeated in a similar manner for other cryotherapy methods. RESULTS Digital venous temperatures were similar to laminar temperatures during each treatment. Ice bag and wader boot treatments caused similar cooling of digits. Gel boot treatment did not cause substantial cooling of digits. CONCLUSIONS AND CLINICAL RELEVANCE Ice bag treatment caused laminar and digital venous cooling equivalent to that of wader boot treatment. Cryotherapy by use of 5-L fluid bags with an ice slurry may be a readily available, practical, and efficient method for prevention of laminitis in horses. Digital laminar and venous temperatures were similar in forelimbs of horses before and during cryotherapy.
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Affiliation(s)
- Heidi L Reesink
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Lancaster LS, Bowker RM. Acupuncture Points of the Horse's Distal Thoracic Limb: A Neuroanatomic Approach to the Transposition of Traditional Points. Animals (Basel) 2012; 2:455-71. [PMID: 26487033 PMCID: PMC4494290 DOI: 10.3390/ani2030455] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 08/31/2012] [Accepted: 09/10/2012] [Indexed: 11/26/2022] Open
Abstract
Veterinary acupuncture charts were developed based on the concept of transpositional points whereby human acupuncture maps were adapted to animal anatomy. Transpositional acupuncture points have traditionally been placed in specific locations around the horse's coronet and distal limb believed to be the closest approximation to the human distal limb points. Because the horse has a single digit and lacks several structures analogous to the human hand and foot, precisely transposing all of the human digital points is not anatomically possible. To date there is no published research on the effect of acupuncture treatment of the equine distal limb points. This paper presents a modified approach to equine distal limb point selection based on what is known from research on other species about the neuroanatomic method of acupuncture. A rationale is presented for modification of traditional equine ting points as well as additional points around the hoof and distal limb that do not appear in the standard textbooks of equine acupuncture. The anatomy and physiology of the equine foot likely to be affected by acupuncture are briefly reviewed. Modified neuroanatomic points are proposed that may be more accurate as transpositional points. As an example of clinical application, a neuroanatomic approach to acupuncture treatment of equine laminitis is presented.
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Affiliation(s)
- Lisa S Lancaster
- Medical Acupuncture for Veterinarians Course, Colorado State University, Fort Collins, CO 80525, USA.
| | - Robert M Bowker
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, G205, East Lansing, MI 48824, USA.
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Douthit TL, Bormann JM, Gradert KC, Lomas LW, DeWitt SF, Kouba JM. The impact of endophyte-infected fescue consumption on digital circulation and lameness in the distal thoracic limb of the horse12. J Anim Sci 2012; 90:3101-11. [DOI: 10.2527/jas.2011-4371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- T. L. Douthit
- Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506
| | - J. M. Bormann
- Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506
| | - K. C. Gradert
- Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506
| | - L. W. Lomas
- Southeast Agricultural Research Center, Kansas State University, Parsons 67357
| | - S. F. DeWitt
- College of Veterinary Medicine, Kansas State University, Manhattan 66506
| | - J. M. Kouba
- Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506
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Borer KE, Bailey SR, Harris PA, Elliott J. Contractile responses of isolated equine digital arteries under hypoxic or hyperoxic conditions in vitro: role of reactive oxygen species and Rho kinase. J Vet Pharmacol Ther 2012; 36:267-74. [PMID: 22762272 DOI: 10.1111/j.1365-2885.2012.01423.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The underlying pathophysiological triggers for equine acute laminitis are unknown, although digital vasoconstriction, ischaemia, hypoxia and reperfusion injury may be involved. The contractile responses of isolated equine digital arteries (EDAs), harvested from the hindlimbs of normal horses postmortem at an abattoir, were studied acutely (up to 3 h) under hyperoxic (95% oxygen, 5% CO2 ) and hypoxic (95% nitrogen, 5% CO2 ) conditions in organ baths. Phenylephrine (PHE; 10(-6) m), 5-hydroxytryptamine (5-HT; 10(-7) m) and high potassium (K(+) ; 118 mm) caused contraction in EDAs which was significantly (P<0.0001) enhanced under hypoxic conditions. In contrast, contraction stimulated by 9,11-dideoxy-9α,11α-epoxymethanoprostaglandin F2α (U44069; 3 × 10(-8) m) was not significantly enhanced by hypoxia (P=0.75). Hypoxia-enhanced contraction in response to K(+) was greater (P<0.03) in vessels with a functional endothelium than in vessels in which the endothelium was removed by rubbing. Fasudil (10(-6) to 10(-5) m), a Rho kinase inhibitor, and apocynin (10(-3) to 3 × 10(-3) m), an NADPH oxidase inhibitor, significantly (P ≤ 0.05) inhibited hypoxia-enhanced contraction in response to PHE and 5-HT. In conclusion, hypoxia-enhanced contraction occurred in EDAs. This appears to be partially mediated by reactive oxygen species produced by NAPDH oxidase, which activate Rho kinase to increase calcium sensitisation and enhance smooth muscle contraction.
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Affiliation(s)
- K E Borer
- Royal Veterinary College, Hatfield, Herts, UK University of Melbourne, Melbourne, Vic., Australia.
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Towards a new treatment for equine acute laminitis: The importance of signalling pathways. Vet J 2012; 192:258-9. [DOI: 10.1016/j.tvjl.2011.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 10/15/2011] [Indexed: 11/19/2022]
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Aljuffali IA, Brainard BM, Moore JN, Kwon S, Allen D, Robertson TP, Arnold RD. Pharmacokinetic assessment of ketanserin in the horse. J Vet Pharmacol Ther 2011; 35:472-7. [PMID: 22091605 DOI: 10.1111/j.1365-2885.2011.01346.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The purpose of this study was to determine the pharmacokinetics (PK) of the 5-HT(2A) receptor antagonist ketanserin in healthy adult horses, and to develop a computational model that could be used to optimize dosing. Plasma concentrations of ketanserin were determined using liquid chromatography with mass spectrometry after single and multiple intravenous administration in the horse. A two-compartment linear pharmacokinetic model described the plasma concentration-time profile of ketanserin after single and multiple doses in healthy horses; the terminal half-life was 11.5 h; steady-state volume of distribution was 10.5 L/kg; AUC was 115 ng · h/mL; and clearance was 0.87 L/h/kg. Model simulations followed by the examination in three healthy horses suggest 0.3 mg/kg q.8 h exhibited linear PK and produced consistent systemic blood concentrations of ketanserin above 3 ng/mL.
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Affiliation(s)
- I A Aljuffali
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2352, USA
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The relationship between digital perfusion pressure and hoof lamellar blood flow in isoflurane-anesthetized horses. Res Vet Sci 2011; 90:138-45. [DOI: 10.1016/j.rvsc.2010.05.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 05/09/2010] [Accepted: 05/11/2010] [Indexed: 11/22/2022]
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Divers TJ. Clinical Application of Current Research Findings Toward the Prevention and Treatment of Acute Laminitis in Horses With Systemic Inflammatory Diseases: An Internist’s Perspective. J Equine Vet Sci 2010. [DOI: 10.1016/j.jevs.2010.07.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zerpa H, Berhane Y, Elliott J, Bailey SR. The effect of cooling on the contractility of equine digital small lamellar arteries: modulating role of the endothelium. Exp Physiol 2010; 95:1033-42. [PMID: 20660021 DOI: 10.1113/expphysiol.2010.053686] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The equine hoof displays thermoregulatory functions, and the blood vessels lying under the hoof wall are temperature sensitive. The aim of this study was to investigate the effect of cooling on the contractile responses to α-adrenoceptor and 5-HT receptor stimulation in equine small lamellar arteries using wire myography. The role of the endothelium in the response mediated by 5-HT was also evaluated. Moderate cooling caused a reduction of the contraction induced by depolarizing Krebs solution (DKS, containing 118 mm KCl) and the maximal contraction caused by UK-14304 (α(2)-adrenoceptor agonist). The potency of methoxamine (α(1)-adrenoceptor agonist) was reduced by cooling [pD(2) (-log EC(50)) at 22°C, 5.7 (5.5-6.0) versus 30°C, 5.9 (5.7-6.1)]; however, the efficacy was maintained. The contractions evoked by sumatripan and α-methyl 5-HT (5-HT receptor agonists) were not modified by moderate cooling. In contrast, a cooling-enhanced contraction was observed in response to 5-HT [maximum response (E(max)) at 22°C, 213.2 ± 13% DKS versus 30°C, 179.9 ± 11% DKS]. Furthermore, this effect was more evident in endothelium-denuded lamellar arteries (E(max) at 22°C, 270.2 ± 26% DKS versus 30°C, 172.2 ± 20% DKS), suggesting a potential modulating role of the endothelium. The L-NAME/ibuprofen-resistant relaxation in response to carbachol was reduced by cooling in small lamellar arteries precontracted with 5-HT but not phenylephrine. Therefore, a moderate reduction of temperature modulates the reactivity of small lamellar arteries by enhancing the 5-HT-mediated contraction, but inhibits the α-adrenoceptor-mediated response. Furthermore, the endothelium of these blood vessels may play an important role in preventing excessive vasoconstriction in response to 5-HT and maintaining digital blood flow in cool environmental temperatures.
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Affiliation(s)
- Hector Zerpa
- Department of Veterinary Basic Sciences, Royal Veterinary College, University of London, London, UK
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Mallem MY, Thuleau A, Noireaud J, Desfontis JC, Gogny M. Evaluation of the role of superoxide anions in endotoxin-induced impairment of β-adrenoceptor-mediated vasodilation in equine digital veins. Am J Vet Res 2010; 71:773-9. [DOI: 10.2460/ajvr.71.7.773] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Castro JR, Adair HS, Radecki SV, Kiefer VR, Elliot SB, Longhofer SL. Effects of domperidone on digital laminar microvascular blood flow in clinically normal adult horses. Am J Vet Res 2010; 71:281-7. [DOI: 10.2460/ajvr.71.3.281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Noschka E, Moore JN, Peroni JF, Lewis TH, Lewis SJ, Robertson TP. Evaluation of the possible role of prostaglandin F2αin laminitis induced in horses by nasogastric administration of black walnut heartwood extract. Am J Vet Res 2010; 71:186-93. [DOI: 10.2460/ajvr.71.2.186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Riggs LM, Krunkosky TM, Noschka E, Boozer LA, Moore JN, Robertson TP. Comparison of characteristics and enzymatic products of leukocytes in the skin and laminar tissues of horses administered black walnut heartwood extract or lipopolysaccharide. Am J Vet Res 2009; 70:1383-90. [DOI: 10.2460/ajvr.70.11.1383] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Patan B, Budras KD, Licka TF. Effects of long-term extracorporeal blood perfusion of the distal portion of isolated equine forelimbs on metabolic variables and morphology of laminar tissue. Am J Vet Res 2009; 70:669-77. [PMID: 19405908 DOI: 10.2460/ajvr.70.5.669] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To establish an ex vivo model of blood perfusion in the distal portion of isolated equine forelimbs that closely represents the in vivo situation in the laminar tissue of the hoof. SAMPLE POPULATION 18 forelimbs collected from 9 healthy adult horses following slaughter at a licensed abattoir. PROCEDURES The distal portion of isolated equine forelimbs from 9 horses were perfused under physiologic conditions over a period of 6, 8, and 10 hours with autologous blood. To determine cell viability in perfused tissues, indicators for metabolism (lactate generation and glucose and oxygen consumption) as well as indicators for cell damage (potassium concentration and lactate dehydrogenase activity) were examined at 1-hour intervals from samples of the perfusate. Weight gain in the forelimb was used to determine the edema index. After perfusion, light and electron microscopic examinations of laminar tissue specimens were performed. RESULTS During hemoperfusion of the isolated forelimbs, mean +/- SD glucose consumption was 197.4 +/- 65.1 mg/h, lactate generation was 1.84 +/- 0.79 mmol/h, and oxygen consumption was 6.4 x 10(-6) +/- 8.9 x 10(-5) mL.g(-1).min(-1). Neither an efflux of potassium into the perfusate nor a relevant increase of the lactate dehydrogenase activity was detected, indicating low amounts of cellular damage in the perfused tissues. Weight gain of forelimbs was 1.02 +/- 0.95%. Histologic and ultrastructural appearance of the laminar tissue revealed no signs of tissue damage. CONCLUSIONS AND CLINICAL RELEVANCE Isolated equine limbs were perfused under physiologic conditions over a period of < or = 10 hours without structural damage to the laminar tissue.
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Affiliation(s)
- Bianca Patan
- Clinic of Orthopaedics in Large Animals, Department of Horses and Small Animals, Vienna University of Veterinary Medicine, A-1210 Vienna, Austria
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Noschka E, Moore JN, Peroni JF, Lewis SJ, Morrow JD, Robertson TP. Thromboxane and isoprostanes as inflammatory and vasoactive mediators in black walnut heartwood extract induced equine laminitis. Vet Immunol Immunopathol 2009; 129:200-10. [DOI: 10.1016/j.vetimm.2008.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Robertson TP, Bailey SR, Peroni JF. Equine laminitis: A journey to the dark side of venous. Vet Immunol Immunopathol 2009; 129:164-6. [DOI: 10.1016/j.vetimm.2008.11.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Menzies-Gow NJ, Bailey SR, Berhane Y, Brooks AC, Elliott J. Evaluation of the induction of vasoactive mediators from equine digital vein endothelial cells by endotoxin. Am J Vet Res 2008; 69:349-55. [PMID: 18312133 DOI: 10.2460/ajvr.69.3.349] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effect of endotoxin (lipopolysaccharide [LPS]) on vasoactive mediator production by cultured equine digital vein endothelial cells (EDVECs). SAMPLE POPULATION EDVECs obtained from forelimb digital veins of 7 healthy adult horses. PROCEDURES EDVECs were incubated with or without LPS (1 microg/mL) for 0, 2, 4, 6, 22, and 24 hours. The EDVECs were incubated for 18 hours with LPS (10 pg/mL to 1 microg/mL) with or without ibuprofen, cycloheximide, or L-nitroarginine methyl ester. Medium concentrations of prostacyclin, cyclic guanosine monophosphate, endothelin-1, and thromboxane A(2) were determined. Changes in inducible nitric oxide synthase and cyclooxygenase-2 expression were determined. RESULTS LPS stimulated mean 4.2- and 14.1-fold increases in EDVEC prostacyclin and cyclic guanosine monophosphate production, respectively, after 22 hours. These effects were LPS concentration-dependent (LPS concentrations that induced a response halfway between the maximum response and baseline of 1.50 and 1.22 ng/mL, respectively). The LPS-induced cyclic guanosine monophosphate production was significantly inhibited (to basal concentrations) by L-nitroarginine methyl ester, and prostacyclin production was inhibited by cycloheximide and ibuprofen. Production of thromboxane A(2) by EDVECs was not detected. Endothelin-1 accumulated in the medium, but LPS did not enhance its production. Inducible nitric oxide synthase expression in EDVECs was not detected with the available antibodies, whereas LPS stimulated cyclooxygenase-2 expression in a time- and concentration-dependent manner. CONCLUSIONS AND CLINICAL RELEVANCE LPS stimulated vasoactive mediator production by equine endothelial cells, which may play a role in LPS-induced digital hypoperfusion.
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Affiliation(s)
- Nicola J Menzies-Gow
- Department of Veterinary Clinical Sciences, Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, England
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Kruger EF, Puchalski SM, Pollard RE, Galuppo LD, Hornof WJ, Wisner ER. Measurement of equine laminar blood flow and vascular permeability by use of dynamic contrast-enhanced computed tomography. Am J Vet Res 2008; 69:371-7. [DOI: 10.2460/ajvr.69.3.371] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Evaluation of equine laminar vein function: harvesting, dissection and the use of functional methods to distinguish between veins and arteries. J Pharmacol Toxicol Methods 2008; 57:92-9. [PMID: 18280185 DOI: 10.1016/j.vascn.2007.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 10/11/2007] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Pharmacological evaluation of the unique equine laminar microvasculature is crucial to understanding its role in health and in diseases such as laminitis. However, separating the distinctive characteristics of arterial versus venous components of this complex vascular network has previously proved to be extremely difficult. Encased in a hard hoof capsule, isolation of individual blood vessels presents a considerable challenge. Exacerbating this difficulty, the laminar venous network is adapted to sustain high intravascular pressures and consequently has thickened walls, making the normally straightforward visual distinction between arteries and veins problematic. Here we describe a novel harvesting and dissection method coupled with a functional analysis procedure that facilitates distinction of arteries and veins. METHODS Laminar tissue was recovered from the hoof of euthanized, clinically normal horses by dissection at the coronary band and stored in cold Krebs-Henseleit physiological salt solution prior to further dissection in the laboratory to remove 2 mm segments of vessels 100-500 microm in diameter. Active length tension measurements were made to evaluate optimal conditions for experimentation, and based on the differences in contractility and appearance, an experimental protocol was set up to allow a) initial distinction between arteries and veins and b) in vitro pharmacological evaluation. RESULTS Active length tension studies clearly revealed the presence of two populations of vessels distinguished by either a large or a lower maximal contraction that subsequent histological evaluation confirmed to be arteries and veins respectively. Functional distinction using relative contractility to 60 mM potassium salt solution then demonstrated equine laminar veins to have increased sensitivity to the agonist endothelin 1 (ET-1) compared to arteries. DISCUSSION In vitro evaluation of laminar vessels is possible despite anatomical obstacles. Furthermore, a clear distinction can be made between laminar veins and arteries using functional characteristics providing vessels of a similar size range are selected. Utilising these novel procedures, investigators can unambiguously analyse the pharmacological characteristics of equine laminar veins and arteries to decipher the physiological mechanisms responsible for the control of laminar blood flow.
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Robertson TP, Moore JN, Noschka E, Lewis TH, Lewis SJ, Peroni JF. Effects of Rho-kinase and Src protein tyrosine kinase inhibition on agonist-induced vasoconstriction of arteries and veins of the equine laminar dermis. Am J Vet Res 2007; 68:886-94. [PMID: 17669029 DOI: 10.2460/ajvr.68.8.886] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of inhibition of Rho-kinase or Src-family protein tyrosine kinases (srcPTK) on agonist-induced contractile responses in equine laminar arteries and veins. SAMPLE POPULATION Laminar arteries and veins obtained from 13 adult mixed-breed horses. PROCEDURES Laminar vessels were mounted on myographs and exposed to phenylephrine (PE), 5-hydroxytryptamine (5-HT), prostaglandin F(2) (PGF(2)), and endothelin-1 (ET-1) with or without the Rho-kinase inhibitor Y-27632 (10 microM), srcPTK inhibitor PP2 (10 microM), or a negative control analogue for PP2 (PP3; 10 microM). RESULTS Responses to PE were reduced by use of Y-27632 in laminar vessels (approx inhibition, 55%). However, Y-27632 reduced responses to 5-HT to a greater degree in veins than in arteries (approx inhibition of 55% and 35%, respectively). The Y-27632 also reduced responses of laminar veins to ET-1 by approximately 40% but had no effect on maximum responses of laminar arteries to ET-1, although a rightward shift in the concentration response curve was evident. Addition of PP2 reduced responses to PE, 5-HT, and PGF(2) in laminar veins by approximately 40%, 60%, and 65%, respectively, compared with responses after the addition of PP3; PP2 had no effect on responses to ET-1. In laminar arteries, PP2 reduced 5-HT-induced contractions by approximately 50% but did not affect responses to PE or ET-1. CONCLUSIONS AND CLINICAL RELEVANCE Results of the study were consistent with activation of Rho-kinase being important during agonist-induced constriction in laminar vessels, activation of srcPTK being an agonist-dependent event, and more prominent roles for Rhokinase and srcPTK in veins than in arteries.
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Affiliation(s)
- Tom P Robertson
- Department of Physiology and Pharmacology, Institute of Comparative Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7389, USA
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Jones E, Viñuela-Fernandez I, Eager RA, Delaney A, Anderson H, Patel A, Robertson DC, Allchorne A, Sirinathsinghji EC, Milne EM, MacIntyre N, Shaw DJ, Waran NK, Mayhew J, Fleetwood-Walker SM. Neuropathic changes in equine laminitis pain. Pain 2007; 132:321-331. [PMID: 17935886 DOI: 10.1016/j.pain.2007.08.035] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 08/23/2007] [Accepted: 08/28/2007] [Indexed: 11/17/2022]
Abstract
Laminitis is a common debilitating disease in horses that involves painful disruption of the lamellar dermo-epidermal junction within the hoof. This condition is often refractory to conventional anti-inflammatory analgesia and results in unremitting pain, which in severe cases requires euthanasia. The mechanisms underlying pain in laminitis were investigated using quantification of behavioural pain indicators in conjunction with histological studies of peripheral nerves innervating the hoof. Laminitic horses displayed consistently altered or abnormal behaviours such as increased forelimb lifting and an increased proportion of time spent at the back of the box compared to normal horses. Electron micrographic analysis of the digital nerve of laminitic horses showed peripheral nerve morphology to be abnormal, as well as having reduced numbers of unmyelinated (43.2%) and myelinated fibers (34.6%) compared to normal horses. Sensory nerve cell bodies innervating the hoof, in cervical, C8 dorsal root ganglia (DRG), showed an upregulated expression of the neuronal injury marker, activating transcription factor-3 (ATF3) in both large NF-200-immunopositive neurons and small neurons that were either peripherin- or IB4-positive. A significantly increased expression of neuropeptide Y (NPY) was also observed in myelinated afferent neurons. These changes are similar to those reported in other neuropathic pain states and were not observed in the C4 DRG of laminitic horses, which is not associated with innervation of the forelimb. This study provides novel evidence for a neuropathic component to the chronic pain state associated with equine laminitis, indicating that anti-neuropathic analgesic treatment may well have a role in the management of this condition.
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Affiliation(s)
- Emma Jones
- Centre for Neuroscience Research, Division of Veterinary Biomedical Sciences, R(D)SVS, The University of Edinburgh, Summerhall, Edinburgh EH9 1QH, Scotland, United Kingdom Division of Veterinary Clinical Sciences, R(D)SVS, The University of Edinburgh, Roslin, Midlothian EH25 9RG, United Kingdom
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Peroni JF, Moore JN, Noschka E, Lewis TH, Lewis SJ, Robertson TP. Effect of voltage-gated and capacitative calcium entry blockade on agonist-induced constriction of equine laminar blood vessels. Am J Vet Res 2007; 68:722-9. [PMID: 17605607 DOI: 10.2460/ajvr.68.7.722] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To characterize the relative contributions of voltage-gated and capacitative Ca(2+) entry to agonist-induced contractions of equine laminar arteries and veins. ANIMALS 16 adult mixed-breed horses. PROCEDURES Laminar arteries and veins were isolated and mounted on small vessel myographs for the measurement of isometric tension. Concentration-response curves were obtained for the vasoconstrictor agonists phenylephrine, 5-hydroxytryptamine (5-HT), prostaglandin F(2) (PGF(2)), and endothelin-1 (ET-1) either in the absence of extracellular Ca(2+) or in the presence of the voltage-gated Ca(2+) channel inhibitor diltiazem or the putative inhibitor of capacitative Ca(2+) entry, trifluoromethylphenylimidazole. RESULTS In the absence of extracellular Ca(2+), maximal responses of veins to 5-HT, phenylephrine, ET-1 and PGF(2) were reduced by 80%, 50%, 50%, and 45%, respectively; responses of arteries to 5-HT, phenylephrine, and ET-1 were reduced by 95%, 90%, and 20%, respectively. Although diltiazem did not affect the maximal responses of veins to any agonist, responses of arteries to 5-HT, phenylephrine, and ET-1 were reduced by 40%, 50%, and 27%, respectively. Trifluoromethylphenylimidazole did not affect maximal responses of veins, but did reduce their contractile responses to low concentrations of ET-1 and PGF(2). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the contribution of extracellular Ca(2+) to laminar vessel contractile responses differs between arteries and veins and also between contractile agonists, voltage-gated Ca(2+) entry is more predominant in laminar arteries than in veins, and capacitative Ca(2+) entry has a minor role in agonist-induced contractile responses of laminar veins.
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Affiliation(s)
- John F Peroni
- Department of Physiology and Pharmacology, Institute of Comparative Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7389, USA
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Behling-Kelly E, Czuprynski CJ. Endothelial cells as active participants in veterinary infections and inflammatory disorders. Anim Health Res Rev 2007; 8:47-58. [PMID: 17692142 DOI: 10.1017/s1466252307001296] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AbstractEndothelial cells were once viewed as relatively inert cells lining the vasculature. They are now recognized as active and responsive regulators of coagulation, platelet adhesion, fluid homeostasis, wound healing, leukocyte extravasation and vascular tone. Endothelial cells play a key role in the host response to infectious agents by regulating leukocyte trafficking, producing inflammatory cytokines and presenting antigen in association with major histocompatibility class II (MHC II) molecules. A number of infectious agents have a tropism for endothelial cells. Infection of endothelial cells can promote thrombosis, vascular leakage, and increased adherence and emigration of leukocytes. Furthermore, activation of a systemic inflammatory response, in the absence of direct endothelial cell infection, can also lead to endothelial cell dysfunction. The purpose of this review is to highlight the interactions between endothelial cells and infectious or inflammatory agents that contribute to coagulation disturbances, vasculitis and edema. A select group of viral and bacterial pathogens will be used as examples to demonstrate how endothelial cell dysfunction contributes to the pathogenesis of infectious and inflammatory disorders.
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Affiliation(s)
- E Behling-Kelly
- Department of Pathobiological Sciences, University of Wisconsin, School of Veterinary Medicine, 2015 Linden Drive, Madsion, WI 53706, USA
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Robertson TP, Moore JN, Noschka E, Lewis TH, Lewis SJ, Peroni JF. Evaluation of activation of protein kinase C during agonist-induced constriction of veins isolated from the laminar dermis of horses. Am J Vet Res 2007; 68:664-9. [PMID: 17542701 DOI: 10.2460/ajvr.68.6.664] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of the protein kinase C (PKC) inhibitor, Ro-31-8220, on agonist-induced constriction of laminar arteries and veins obtained from horses. SAMPLE POPULATION Laminar arteries and veins obtained from 8 adult mixed-breed horses. PROCEDURES Laminar arteries and veins were isolated and mounted on small vessel myographs for the measurement of isometric tension. Concentration-response curves were then obtained for the vasoconstrictor agonists phenylephrine, 5-hydroxytryptamine, prostaglandin F(2), and endothelin-1. All responses were measured with or without the addition of Ro-31-8220 (3 microM). RESULTS Laminar veins were more sensitive to vasoconstrictor agonists than laminar arteries, and incubation of laminar veins with Ro-31-8220 resulted in significantly smaller agonist-induced contractile responses for all agonists tested. In contrast, Ro-31-8220 had no effect on agonist-induced contractile responses of laminar arteries. CONCLUSIONS AND CLINICAL RELEVANCE Results of the study were consistent with activation of PKC being confined to agonist-induced contraction of laminar veins isolated from the laminar dermis of horses. Consequently, the possible involvement of PKC in the venoconstriction observed during the development of laminitis is worthy of further investigation.
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Affiliation(s)
- Tom P Robertson
- Department of Physiology and Pharmacology, Institute of Comparative Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7389, USA
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