Comparison of differential metabolites in brain tissue of aged marmosets and serum of elderly patients after prolonged anesthesia

OBJECTIVE: To compare the differential metabolites in the brain tissue of aged marmosets after long-term anesthesia (≥ 6 h) and the serum of elderly patients by metabolomics methods. METHODS: Six aged marmosets (≥ 8 years old) were divided into two groups: anesthesia and control. The aged monkeys in the anesthesia group were induced with 6–8% sevoflurane and 100% oxygen (2 l/min) for 1–2 min and maintained with 1.5–2.5% sevoflurane and 100% oxygen (2 l/min) for 6 h. In the control group (n = 3), anesthesia was only induced under the same conditions for 1–2 min. The prefrontal cortex tissues of the two groups of aged marmosets were collected for metabolomics detection. Twenty-nine elderly patients (≥ 65 years old) who had undergone surgical anesthesia for more than 6 h were enrolled. Serum samples were collected before and on the first day after surgery for metabolomics analysis. Differential metabolites were compared between human serum and marmoset brain tissue. RESULTS: The changes in lactate and xanthurenic acid in the serum of elderly patients were consistent with those in the brain tissue of aged marmoset monkeys, that is, lactate was up-regulated and xanthurenic acid was down-regulated. However, serum levels of 5-methylterahydrofolic acid and leucine were down-regulated in elderly patients after anesthesia. In contrast, 5-methylterahydrofolic acid and leucine levels were up-regulated in the prefrontal cortex of aged marmosets compared with control marmosets. Furthermore, glycolysis/gluconeogenesis and pentose phosphate pathway were both significantly enriched in the prefrontal cortex of aged marmosets and serum of elderly patients after surgery. CONCLUSION: The changes of serum metabolites in elderly patients are not exactly the same as the metabolic changes of brain tissues in aged marmosets. The metabolic changes in serum lactate and xanthurenic acid levels can reflect brain tissue metabolism. The enrichment pathways of differential metabolites in the serum of elderly patients and the brain tissue of aged marmosets were partially the same.