title: Systemic and colonic venous plasma biochemical alterations in horses during low-flow ischemia and reperfusion of the large colon.
abstract: The purpose of this study was to determine the effects of low-flow ischemia and reperfusion (I-R) of the large colon on 16 systemic venous (SV) and colonic venous (CV) plasma biochemical variables in horses. Horses (n = 24) were randomly allocated to 3 groups: sham-operated (n = 6), 6 h ischemia (n = 9), and 3 h ischemia followed by 3 h reperfusion (n = 9). SV and CV heparinized blood was collected at 0, 1, 3, 3.25, 4, and 6 h. The SV-CV difference was calculated for each variable. The SV, CV, and SV-CV difference for albumin, total protein, and calcium decreased significantly (P < 0.05) across time in horses of all groups, but there were no differences among groups. SV phosphorous was significantly increased from baseline (BL) at 1 to 6 h in horses of all groups, but there were no differences among groups. CV phosphorous was significantly greater than BL from 1 to 6 h in group-2 horses and from 1 to 3 h in group-3 horses. SV potassium was not different among groups, but was significantly higher at 6 h, compared with BL in horses of all groups. CV potassium was significantly greater than BL from 1 to 6 h in horses of groups 2 and 3. SV glucose was greater at 6 h compared with all previous times in horses of all groups, but there were no difference among groups. CV glucose was significantly lower than BL and group-1 values in horses of groups 2 and 3 during ischemia, but returned to BL during reperfusion in group-3 horses. CV anion gap was significantly greater and SV-CV anion gap was significantly more negative in horses of groups 2 and 3, compared with group-1 horses during ischemia. The biologic relevance of these alterations is unknown, but they may contribute to histopathologic, hemodynamic, and metabolic alterations characteristic of low-flow I-R. Alternatively, these alterations may simply reflect colonic injury sustained during I-R. Results suggest that the colon utilizes glucose as a fuel and generates acid anions during low-flow ischemia. Increased CV phosphorous and potassium during I-R likely occurs as a result of leakage of intracellular stores subsequent to cellular damage.
authors.affiliation: Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803-8410, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Moore
authors.forename: W W
authors.initials: WW
authors.lastname: Muir
authors.forename: B R
authors.initials: BR
authors.lastname: Rush
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D000704:Analysis of Variance; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism*; D003106:Colon / Q000098:blood supply*; D003402:Creatine Kinase / Q000097:blood; D004573:Electrolytes / Q000097:blood*; D005260:Female; D006736:Horses / Q000097:blood*; D007511:Ischemia / Q000097:blood*; D008297:Male; D015424:Reperfusion; D013997:Time Factors; D014680:Veins
chemical_list: D001786:Blood Glucose; D001798:Blood Proteins; D004573:Electrolytes; D001219:Aspartate Aminotransferases; D003402:Creatine Kinase; D000469:Alkaline Phosphatase