Serial alterations in digital hemodynamics and endothelin-1 immunoreactivity, platelet-neutrophil aggregation, and concentrations of nitric oxide, insulin, and glucose in blood obtained from horses following carbohydrate overload.
OBJECTIVE
To quantify changes in endothelium-derived factors and relate those changes to various aspects of digital hemodynamics during the prodromal stages of carbohydrate overload (CHO)-induced laminitis in horses.


METHODS
20 adult horses without abnormalities of the digit.


METHODS
Digital and jugular venous blood samples were collected at 1-hour intervals (for assessment of endothelin-1 [ET-1] immunoreactivity and measurement of glucose, insulin, and nitric oxide [NO] concentrations) or 4-hour intervals (CBC and platelet-neutrophil aggregate assessment) for 8 hours or 16 hours after induction of CHO-associated laminitis in horses treated with an ET-1 antagonist. Effects of treatment, collection site, and time and the random effects of horse on each variable were analyzed by use of a repeated-measures model. Where treatment and collection site had no significant effect, data were combined.


RESULTS
Compared with baseline values, CHO resulted in changes in several variables, including a significant increase from baseline in digital blood ET-like immunoreactivity at 11 hours; digital blood ET-like immunoreactivity was significantly greater than that in jugular venous blood at 8, 9, 11, and 12 hours. Digital and jugular venous blood concentrations of glucose increased from baseline significantly at 3, 4, and 5 hours; insulin concentration increased significantly at 5 hours; and the number of platelet-neutrophil aggregates increased significantly at 12 hours.


CONCLUSIONS
In horses, concurrent increases in venous blood ET-1 immunoreactivity, insulin and glucose concentrations, and platelet-neutrophil aggregates support a role of endothelial dysfunction in the pathogenesis of CHO-induced laminitis.
Eades
Susan C
SC
Equine Health Studies Program, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA.
Stokes
Ashley M
AM
Johnson
Philip J
PJ
LeBlanc
Casey J
CJ
Ganjam
Venkataseshu K
VK
Buff
Preston R
PR
Moore
Rustin M
RM
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001792:Blood Platelets / Q000502:physiology; D002241:Carbohydrates / Q000009:adverse effects*; D019332:Endothelin-1 / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005534:Foot Diseases / Q000097:blood / Q000378:metabolism / Q000662:veterinary*; D005552:Forelimb / Q000098:blood supply*; D006400:Hematocrit / Q000662:veterinary; D006724:Hoof and Claw / Q000098:blood supply*; D006734:Horse Diseases / Q000097:blood*; D006736:Horses; D007328:Insulin / Q000097:blood; D007958:Leukocyte Count / Q000662:veterinary; D009504:Neutrophils / Q000502:physiology; D009569:Nitric Oxide / Q000097:blood; D010974:Platelet Aggregation / Q000502:physiology*
D001786:Blood Glucose; D002241:Carbohydrates; D019332:Endothelin-1; D007328:Insulin; D009569:Nitric Oxide