Microdialysis measurements of equine lamellar perfusion and energy metabolism in response to physical and pharmacological manipulations of blood flow

Medina-Torres, C.E., Underwood, C., Pollitt, C.C., Castro-Olivera, E.M., Hodson, M.P., Richardson, D.W. and van Eps, A.W. (2015) Microdialysis measurements of equine lamellar perfusion and energy metabolism in response to physical and pharmacological manipulations of blood flow. Equine Veterinary Journal, 48 6: 756-764. doi:10.1111/evj.12511


Author Medina-Torres, C.E.
Underwood, C.
Pollitt, C.C.
Castro-Olivera, E.M.
Hodson, M.P.
Richardson, D.W.
van Eps, A.W.
Title Microdialysis measurements of equine lamellar perfusion and energy metabolism in response to physical and pharmacological manipulations of blood flow
Journal name Equine Veterinary Journal   Check publisher's open access policy
ISSN 2042-3306
0425-1644
Publication date 2015-01-01
Year available 2015
Sub-type Article (original research)
DOI 10.1111/evj.12511
Open Access Status Not yet assessed
Volume 48
Issue 6
Start page 756
End page 764
Total pages 9
Place of publication Hoboken, NJ, United States
Publisher John Wiley & Sons
Language eng
Formatted abstract
Reasons for performing study: A suitable method for evaluating lamellar perfusion changes and their metabolic consequences is currently lacking.

Objectives: To examine perfusion changes in lamellar tissue using serial microdialysis measurements of urea clearance and energy metabolites.

Study design: Randomised, controlled (within subject) experimental trial.

Methods: Nine Standardbred horses were instrumented with microdialysis probes in the foot lamellar tissue and skin (over the tail base). Urea (20 mmol/l) was added to the perfusate and its clearance was used to estimate local perfusion. Samples were collected every 15 min for a 1 h control period, then during application of a distal limb tourniquet, during periods when norepinephrine or potassium chloride (KCl) were included in both skin and lamellar perfusates, and after systemic (intravenous) acetylpromazine. Dialysate concentrations of glucose, lactate, pyruvate and urea were measured and lactate:glucose (L:G) and lactate:pyruvate (L:P) ratios calculated. Values were compared with pre-intervention baseline and also between simultaneous skin and lamellar samples using nonparametric statistical methods.

Results: Lamellar glucose decreased and lactate, urea, L:G and L:P increased significantly with tourniquet application, without significant changes in skin dialysate values. Lamellar and skin glucose decreased and L:G increased significantly during norepinephrine infusion, but mild increases in urea were not significant at either site. KCl caused significant decreases in lamellar and skin L:G, and an increase in skin glucose, but did not affect urea clearance. Acetylpromazine caused profound decreases in lamellar glucose and L:P, with increased L:G and pyruvate, but did not affect urea clearance or any skin dialysate values.

Conclusions: Significant changes in microdialysis urea clearance only occurred with severe lamellar hypoperfusion. However, changes in dialysate metabolite concentrations reflected less profound fluctuations in perfusion. This method may be useful for examining lamellar perfusion and energy balance during laminitis development and for the evaluation of vasoactive therapeutics.
Keyword Horse
Bioenergetic
Laminitis
Metabolite
Microdialysis
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Veterinary Science Publications
Australian Institute for Bioengineering and Nanotechnology Publications
 
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