Relationships between adiponectin and matrix metalloproteinase-9 (MMP-9) serum levels and postoperative cognitive dysfunction in elderly patients after general anesthesia

OBJECTIVE: The aim of this study was to evaluate the relationships between the serum levels of adiponectin (ADP) and matrix metalloproteinase-9 (MMP-9) and postoperative cognitive dysfunction (POCD) in elderly patients after general anesthesia. METHODS: The cognitive functions of 98 elderly patients who were scheduled to undergo selective hip replacement surgery under general anesthesia were assessed using the Montreal Cognitive Assessment (MoCA) 3 days before surgery and on postoperative Days 1, 2, 3, and 7. The serum levels of ADP and MMP-9 were determined at the same time points, and the presence of POCD on postoperative Day 3 was recorded. The patients were divided into a POCD group and non-POCD group. RESULTS: Postoperative cognitive dysfunction was observed in 28 patients (28.5 %). Serum MMP-9 levels significantly increased and serum ADP levels significantly decreased in the POCD group at each postoperative time point and in the non-POCD group on postoperative Days 1 and 2 compared to the presurgical levels. Serum MMP-9 levels were significantly higher and serum ADP levels were significantly lower in the POCD group compared with those in the non-POCD group at each time point. In the POCD patients, serum MMP-9 levels were significantly and negatively correlated and serum ADP levels were significantly and positively correlated with the MoCA scores. CONCLUSIONS: The increased serum MMP-9 levels and decreased serum ADP levels in elderly patients after general anesthesia might be involved in the POCD pathophysiological process.