Do changes in S100beta protein correlate with serum magnesium concentrations in patients undergoing extracorporeal...

There are many biochemical markers demonstrating the central nervous system (CNS) damage following coronary artery bypass grafting (CABG). The protein S100beta is one of them and its concentrations depend on the severity of CNS damage. On the other hand, it is well known that the brain injury results in a decrease in brain magnesium (Mg) concentration, which is strictly correlated with the serum Mg concentration. Therefore, analysis of the correlation between serum total Mg and S100beta concentrations may be important and interesting, particularly in patients undergoing surgical myocardial revascularization. Patients undergoing CABG with extracorporeal circulation under general anaesthesia were included in the study. Serum Mg and S100beta concentrations were measured at 5 measurement points: 1) just after the radial artery cannulation, 2) 10 min after completion of ECC, 3) just after surgery, 4) in the morning of the 1st postoperative day, 5) in the morning of the 2nd postoperative day. The Kruskall-Wallis ANOVA and Spearman correlation tests were used; p < 0.05 was considered as significant. Twenty male patients, aged 54-70 years (63.3 +/- 49.5) were examined. The mean blood concentration of S100beta was 0.13 microg/L +/- 0.08 and of Mg-0.99mmol/L +/- 0.13 at measurement point 1. S100beta increased from point 2 to 4. Mg decreased at points 2 and 3. Moreover, there were significant negative correlations between S100beta and Mg at point 3 and 4 (p < 0.001; R = -0.76; p < 0.05; R = -0.5, respectively) and between Mg at point 1 and S100beta at point 3 and 5 (p < 0.05, R = -0.498; p < 0.05, R = -0.488, respectively), Mg at point 2 and S100beta at point 4 (p < 0.05, R = -0.523) as well as Mg at point 4 and S100beta at point 5 (p < 0.01, R = -0.584).

1) S100beta increased while total Mg decreased during CABG, 2) The highest serum S100beta concentrations were noted just after surgery, 3) The changes in serum S100beta concentrations correlated with those in serum total Mg concentrations, 4) The decrease in serum magnesium concentrations resulted in an elevation in serum S100beta concentrations.