The Influence of Fasting and Anesthesia on Cerebral Metabolism of Hyperpolarized Pyruvate

Motivation: Fasting is a common procedure to reduce physiological variability and to facilitate surgical procedures. Anesthesia is commonly employed in preclinical research. [1-13C] pyruvate is the gold standard hyperpolarized metabolic contrast agent, since it allows detecting metabolic changes within less than one minute. Goal(s): Here we aim to investigate how anesthesia and fasting influence cerebral metabolism of hyperpolarized [1-13C]pyruvate. Approach: Dynamic MRSI at high spatiotemporal resolution characterized HP pyruvate metabolism. Results: Pyruvate-to-lactate turnover is slower and lower under medetomidine-isoflurane than isoflurane-only anesthesia. Only when mice were anesthetized with medetomidine-isoflurane fasting led to longer decay of the pyruvate signal. Impact: Fasting and anesthesia influence brain metabolism and consciousness. Higher pyruvate-to-lactate turnover is observed in mice under isoflurane-only than medetomidine-isoflurane anesthesia. Besides the relevance for preclinical studies, this opens opportunities for probing brain biochemistry in anesthetized patients and influence of fasting.