Increase in serum S100A1-B and S100BB during cardiac surgery arises from extracerebral sources

Background. Elevated levels of serum S100B after coronary artery bypass gra fting may arise from extracerebral contamination. Serum S100B content was a nalyzed in several tissues, and the two dimers S100A1-B and S100BB were ana lyzed separately in blood. Methods. Serum, shed blood, marrow, fat, and muscle were studied in patient s undergoing coronary artery bypass grafting with cardiopulmonary bypass us ing suction either to the cardiotomy reservoir (group 1, n = 10) or to a ce ll-saving device (group 2, n = 10), or operated on oh-pump (group 3, n = 10 ). Results. Serum S100B was sixfold higher in group 1 than in groups 2 and 3, which were identical. The same ratio between S100A1-B and S100BB was found in all groups. When compared with serum, S100B was 10(2) to 10(4) times hig her in marrow, fat, muscle tissue, and shed blood. Conclusions. Separate analysis of S100A1-B and S100BB did not distinguish b etween S100B of cerebral and extracerebral origin. The concept that S100B o nly originates in astroglial and Schwann cells is wrong. Fat, muscle, and m arrow in mediastinal blood contain high levels of S100B. Cardiopulmonary by pass caused no increase in S100B. (Ann Thorac Surg 2001;71:1512-7) (C) 2001 by The Society of Thoracic Surgeons.