• 1

    Hood DM. The pathophysiology of developmental and acute laminitis. Vet Clin North Am Equine Pract 1999;15:321341.

  • 2

    Galey FD, Whiteley HE, Goetz TE, et al. Black walnut (Juglans nigra) toxicosis: a model for equine laminitis. J Comp Pathol 1991;104:313326.

    • Search Google Scholar
    • Export Citation
  • 3

    Hurley DJ, Parks RJ, Reber AJ, et al. Dynamic changes in circulating leukocytes during the induction of equine laminitis with black walnut extract. Vet Immunol Immunopathol 2006;110:195206.

    • Search Google Scholar
    • Export Citation
  • 4

    Fontaine GL, Belknap JK, Allen D, et al. Expression of interleukin-1B in the digital laminae of horses in the prodromal stage of experimentally induced laminitis. Am J Vet Res 2001;62:714720.

    • Search Google Scholar
    • Export Citation
  • 5

    Black SJ, Lunn DP, Yin C, et al. Leukocyte emigration in the early stages of laminitis. Vet Immunol Immunopathol 2006;109:161166.

  • 6

    Morgan SJ, Hood DM, Wagner IP, et al. Submural histopathologic changes attributable to peracute laminitis in horses. Am J Vet Res 2003;64:829834.

    • Search Google Scholar
    • Export Citation
  • 7

    Pollitt CC. Basement membrane pathology: a feature of acute equine laminitis. Equine Vet J 1996;28:3846.

  • 8

    French KR, Pollitt CC. Equine laminitis: glucose deprivation and MMP activation induce dermo-epidermal separation in vitro. Equine Vet J 2004;36:261266.

    • Search Google Scholar
    • Export Citation
  • 9

    French KR, Pollitt CC. Equine laminitis: loss of hemidesmosomes in hoof secondary epidermal lamellae correlates to dose in an oligofructose induction model: an ultrastructural study. Equine Vet J 2004;36:230235.

    • Search Google Scholar
    • Export Citation
  • 10

    Faleiros RR, Stokes AM, Eades SC, et al. Assessment of apoptosis in epidermal lamellar cells in clinically normal horses and those with laminitis. Am J Vet Res 2004;65:578585.

    • Search Google Scholar
    • Export Citation
  • 11

    Foster AP, Lees P, Cunningham FM. Platelet activating factor mimics antigen-induced cutaneous inflammatory responses in sweet itch horses. Vet Immunol Immunopathol 1995;44:115128.

    • Search Google Scholar
    • Export Citation
  • 12

    Franck T, Grulke S, Deby-Dupont G, et al. Development of an enzyme-linked immunosorbent assay for specific equine neutrophil myeloperoxidase measurement in blood. J Vet Diagn Invest 2005;17:412419.

    • Search Google Scholar
    • Export Citation
  • 13

    Weiss SJ. Tissue destruction by neutrophils. N Engl J Med 1989;320:365376.

  • 14

    Deby-Dupont G, Grulke S, Caudron I, et al. Equine neutrophil myeloperoxidase in plasma: design of a radio-immunoassay and first results in septic pathologies. Vet Immunol Immunopathol 1998;66:257271.

    • Search Google Scholar
    • Export Citation
  • 15

    Grulke S, Benbarek H, Caudron I, et al. Plasma myeloperoxidase level and polymorphonuclear leukocyte activation in horses suffering from large intestinal obstruction requiring surgery: preliminary results. Can J Vet Res 1999;63:142147.

    • Search Google Scholar
    • Export Citation
  • 16

    Mathy-Hartert M, Bourgeois E, Grulke S, et al. Purification of myeloperoxidase from equine polymorphonuclear leucocytes. Can J Vet Res 1998;62:127132.

    • Search Google Scholar
    • Export Citation
  • 17

    McConnico RS, Weinstock D, Poston ME, et al. Myeloperoxidase activity of the large intestine in an equine model of acute colitis. Am J Vet Res 1999;60:807813.

    • Search Google Scholar
    • Export Citation
  • 18

    Loftus JP, Belknap JK, Black SJ. Matrix metalloproteinase-9 in laminae of black walnut extract treated horses correlates with neutrophil abundance. Vet Immunol Immunopathol 2006;113:267276.

    • Search Google Scholar
    • Export Citation
  • 19

    Minnick PD, Brown CM, Braselton WE, et al. The induction of equine laminitis with an aqueous extract of the heartwood of black walnut (Juglans nigra). Vet Hum Toxicol 1987;29:230233.

    • Search Google Scholar
    • Export Citation
  • 20

    Franck T, Kohnen S, Deby-Dupont G, et al. A specific method for measurement of equine active myloperoxidase in biologic samples and in vitro tests. J Vet Diagn Invest 2006;18:326334.

    • Search Google Scholar
    • Export Citation
  • 21

    McConnico RS, Stokes AM, Eades SC, et al. Investigation of the effect of black walnut extract on in vitro ion transport and structure of equine colonic mucosa. Am J Vet Res 2005;66:443449.

    • Search Google Scholar
    • Export Citation
  • 22

    Pollitt CC, Pass MA, Pollitt S. Batimastat (BB-94) inhibits matrix metalloproteinases of equine laminitis. Equine Vet J 1998;suppl 26:119124.

    • Search Google Scholar
    • Export Citation
  • 23

    Mungall BA, Pollitt CC. Zymographic analysis of equine laminitis. Histochem Cell Biol 1999;112:467472.

  • 24

    Weiss DJ, Evanson OA. Evaluation of activated neutrophils in the blood of horses with colic. Am J Vet Res 2003;64:13641368.

  • 25

    Nicholls SJ, Hazen SL. Myeloperoxidase and cardiovascular disease. Arterioscler Thromb Vasc Biol 2005;25:11021111.

  • 26

    Harrison DG. Endothelial function and oxidant stress. Clin Cardiol 1997;20 (suppl 2):II11II17.

  • 27

    Forgione MA, Leopold JA, Loscalzo J. Roles of endothelial dysfunction in coronary artery disease. Curr Opin Cardiol 2000;15:409415.

  • 28

    Vita JA, Brennan ML, Gokce N, et al. Serum myeloperoxidase levels independently predict endothelial dysfunction in humans. Circulation 2004;110:11341139.

    • Search Google Scholar
    • Export Citation
  • 29

    Abu-Soud HM, Khassawneh MY, Sohn JT, et al. Peroxidases inhibit nitric oxide (NO) dependent bronchodilation: development of a model describing NO-peroxidase interactions. Biochemistry 2001;40:1186611875.

    • Search Google Scholar
    • Export Citation

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Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract

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  • 1 Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 2 Department of Clinical Sciences, Equine Clinic, Faculty of Veterinary Medicine, University of Liège, Sart Tilman, 4000 Liège, Belgium.
  • | 3 Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 4 Department of Anatomy and Radiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 5 Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 6 Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 7 Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
  • | 8 Department of Clinical Sciences, Equine Clinic, Faculty of Veterinary Medicine, University of Liège, Sart Tilman, 4000 Liège, Belgium.
  • | 9 Department of Clinical Sciences, Equine Clinic, Faculty of Veterinary Medicine, University of Liège, Sart Tilman, 4000 Liège, Belgium.

Abstract

Objective—To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE).

Animals—22 healthy 5- to 15-year-old horses.

Procedures—Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection.

Results—Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time.

Conclusions and Clinical Relevance—In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.

Abstract

Objective—To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE).

Animals—22 healthy 5- to 15-year-old horses.

Procedures—Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection.

Results—Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time.

Conclusions and Clinical Relevance—In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.

Contributor Notes

Supported by an American Quarter Horse Association research grant.

Presented in abstract form at the American Association of Equine Practitioners Equine Colic Research Symposium, Quebec City, QC, Canada, August 2005.

Address correspondence to Dr. Riggs.