Serum high-mobility group box 1 protein correlates with cognitive decline after gastrointestinal surgery

Background Accumulating evidence has indicated that inflammation may act as a potential mechanism underlying post-operative cognitive dysfunction (POCD). High-mobility group box 1 (HMGB1), as a known late mediator of inflammation, is involved in the development of post-operative complications. Thus, we sought to determine the role of HMGB1 in reflecting POCD following major gastrointestinal surgery. Methods Fifty-three elderly patients undergoing gastrointestinal surgery were recruited, and 50 patients completed the study. Serum HMGB1 and interleukin (IL)-6 levels were measured pre-operatively and at 6h, day 1 and day 3 post-operatively. Neuropsychological tests were administered before and 1 week after surgery. POCD was determined using a Z score1.96. Results Seventeen (34%, 17/50) patients developed POCD at 1 week. The POCD group had higher serum HMGB1 levels at day 1 (12.15 +/- 3.12 vs. 9.91 +/- 3.15ng/ml, P=0.021) and day 3 (11.04 +/- 2.88 vs. 8.52 +/- 3.31ng/ml, P=0.011). IL-6 levels at 6h (51.18 +/- 15.22 vs. 39.20 +/- 14.32pg/ml, P=0.009) and day 1 (41.59 +/- 11.08 vs. 33.81 +/- 11.42pg/ml, P=0.026) were significantly higher in POCD patients. Serum values of IL-6 at 6h, HMGB1 at day 1 and levels of education showed positive correlations with Z scores. HMGB1 at day 3 and IL-6 at 6h were independent risk factors. Conclusions Serum HMGB1 and IL-6 levels increase significantly after major gastrointestinal surgery in elderly patients and such elevations are associated with the occurrence of cognitive decline after surgery.