Acute changes in hippocampal metabolism after anesthesia and surgery: Implications for perioperative neurocognitive...

The risk of developing dementia is higher in individuals who suffer from perioperative neurocognitive disorder (PND), including postoperative cognitive dysfunction (POCD) and delirium. Recent studies have indicated correlations between anesthesia, surgery and PND. Acute metabolic changes induced by anesthesia and surgery may be related to cognitive impairments. Despite a paucity of research on acute metabolic changes in the hippocampus during surgery, there are conflicting about specific metabolites.

We developed a mouse model of cognitive impairment induced by isoflurane anesthesia and unilateral nephrectomy. Cognition was evaluated by Y maze and fear conditioning test (FCT). The hippocampus was harvested after the surgery. LC-MS (liquid chromatography-mass spectrometry) was performed. The differential metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were analyzed.

Anesthesia and surgery exposure induced cognition decline. A total of 49 metabolites were significantly up-regulated and 122 down-regulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway of the metabolites identified purine, glutathione, nicotinate and nicotinamide metabolism. Metabolites involved in lipid, amino acid, nucleotide, carbohydrate metabolism were identified including nicotinamide adenine dinucleotide (NAD), 1-Methylnicotinamide, propionic acid, histidine, adenosine, and guanosine cyclic monophosphate. Some metabolites exhibited a consistent change trend in the hippocampus of aging mice.

The study indicates that anesthesia and surgery can induce acute alterations in hippocampal metabolomics, including metabolites involved in lipid, amino acid, nucleotide, and carbohydrate metabolism. These metabolites may play a role in modulating PND through the regulation of neuroinflammation, oxidative stress, blood-brain barrier (BBB) permeability.