Perioperative cerebrospinal fluid sorbitol and fructose concentrations in patients undergoing thoracic aortic surgery

Editor—In the polyol pathway, glucose is metabolised to the neurotoxic metabolites sorbitol and fructose, which increase oxidative stress and damage intracellular proteins.1 These polyols are implicated in the development of white matter lesions, cognitive impairment, and complications of diabetes mellitus.1,2 Sparse data are available regarding cerebral activation of the polyol pathway.3 The brain is the primary source of polyols in cerebrospinal fluid (CSF),3 with levels up to 20 times higher than in plasma.