Plasma homocysteine measurements after carotid artery manipulation and clamping in a rat CEA model.
OBJECTIVE
The effect of a rat carotid endarterectomy (CEA) on homocysteine and the metabolic enzymes methylenetetrahydrofolate reductase (MTHFR) and cystathionine beta-synthase (CBS) was studied.


METHODS
Rats were placed into 7 groups: (1) no anesthesia (NA), (2) anesthesia only (AO), (3) skin opened and closed (O/C), (4) skin opened with exposure of the carotid artery and closed (O/E/C), (5) carotid isolated and clamped (CO), (6) open CEA, and (7) open femoral endarterectomy (FEA). End points included homocysteine, hepatic MTHFR, and CBS activity.


RESULTS
Homocysteine in the NA, AO, O/C, O/E/C, and FEA were low and not different. CEA produced a 6-fold increase in homocysteine when compared with non-CEA groups. Specifically, CEA produced an increase in homocysteine versus the AO group at 2 weeks (11.3 +/- 0.7 vs 2.1 +/- 0.9 micromol/L;P < .001), 4 weeks (8.9 +/- 0.7 vs 3.5 +/- 0.9 micromol/L; P = .004) and 6 weeks (7.7 +/- 0.9 vs 3.1 +/- 1.5 micromol/L; P = .03). The CO group had increased homocysteine versus the O/C, O/E/C, and FEA, but was lower than the CEA group. CEA produced an increase in MTHFR and CBS versus the AO group.


CONCLUSIONS
CEA resulted in elevated levels of homocysteine; however, when broken down into its component parts, no elevation was observed except for a small increase with the CO procedure. Manipulation of the femoral artery did not raise homocysteine levels. The increase in homocysteine is possibly due to the combination of vessel wall damage and changes in cerebral blood flow dynamics.
University of Arkansas for Medical Sciences, Central Arkansas Veterans HealthCare System, Little Rock 72205, USA.
Aliza T
AT
Brown
Hongjiang
H
Chen
Joseph A
JA
Davis
Irfan
I
Qureshi
Carlos P
CP
Cruz
Lionel A
LA
Poirier
John F
JF
Eidt
Mohammed M
MM
Moursi
D000818:Animals; D002339:Carotid Arteries / Q000601:surgery*; D003250:Constriction; D003541:Cystathionine beta-Synthase / Q000097:blood; D016894:Endarterectomy, Carotid / Q000379:methods*; D006710:Homocysteine / Q000097:blood*; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000097:blood; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley
D006710:Homocysteine; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D003541:Cystathionine beta-Synthase