Elevation of serum cerebral injury markers correlates with serum choline decline after coronary artery bypass grafting surgery

The aims of this study were to determine circulating choline status and its relationship to circulating levels of S-100b protein and neuron-specific enolase, biochemical markers of cerebral injury and cognitive decline, after coronary artery bypass grafting ( CABG) surgery. Preoperatively, patients scheduled for off-pump or on- pump CABG surgery had serum concentrations of 12.0 +/- 0.2 and 11.7 +/- 0.4 mmol/L free choline and 2640 +/- 65 and 2675 +/- 115 mmol/L phospholipid-bound choline, respectively. Serum free and bound choline levels decreased by 22-37% or 34-47% and 16-36% or 31-38% at 48 h after off-pump or on- pump surgery, respectively. Serum S-100b and neuron-specific enolase increased from preoperative values of 0.083 +/- 0.009 and 6.3 +/- 0.2 mg/L to 0.405 +/- 0.022 and 11.4 +/- 0.8 mg/L, respectively, at 0 h postoperatively and remained elevated for 48 h after off-pump surgery. Serum free and bound choline concentrations were inversely correlated with the concentrations of S-100b ( r=-0.798; p<0.001 and r=-0.734; p<0.001) and neuron-specific enolase ( r=-0.840; p<0.001 and r=-0.728; p<0.001). In conclusion, CABG surgery induces a decline in serum free and phospholipid-bound choline concentrations. The decreased serum choline concentrations were inversely correlated with the elevated levels of circulating cerebral injury markers. Thus, a decline in circulating choline may be involved in postoperative cognitive decline.