Abstract # 1704 Cardiac surgery causes more extended neuroinflammation and cognitive dysfunction compared to abdominal surgery in rats

Abstract

Postoperative cognitive dysfunction (POCD) is a debilitating surgical complication, often affecting cardiac surgery patients. The current study aimed to gain insight in the mechanisms causing POCD after cardiac versus non-cardiac surgery. Adult male Wistar rats underwent abdominal or cardiac surgery including ischemia reperfusion of the mesenteric or coronary vasculature, respectively. Control rats remained naive, received anesthesia only, or received thoracic sham surgery. Two weeks after surgery, rats were subjected to behavioral tests and systemic and central concentrations of inflammatory factors and the neuronal markers brain-derived neurotrophic factor (BDNF) and doublecortin (DCX) were analyzed. Spatial memory was impaired after both abdominal and cardiac surgery, but only cardiac surgery impaired spatial learning and object recognition. While all surgical procedures elicited a pronounced acute systemic inflammatory response, neutrophil gelatin-associated lipocalin (NGAL) and TNF- α levels were particularly increased after abdominal surgery. Conversely, NGAL in plasma and the paraventricular nucleus were increased 14 days after cardiac, but not after abdominal surgery. In the hippocampus, both surgeries induced increased levels of NGAL and decreased BDNF and neurogenesis (DCX). These results suggest that POCD affects different cognitive domains, and hence may be more extended rather than more severe, after cardiac versus non-cardiac surgery. Moreover, while abdominal surgery effects seem limited to the hippocampus, cardiac surgery effects seem associated with more wide spread alterations in the brain.