Age‐associated change in pyruvate metabolism investigated with hyperpolarized (13)C‐MRI of the human brain

In this study, hyperpolarized (13)C MRI (HP‐(13)C MRI) was used to investigate changes in the uptake and metabolism of pyruvate with age. Hyperpolarized (13)C‐pyruvate was administered to healthy aging individuals (N = 35, ages 21–77) and whole‐brain spatial distributions of (13)C‐lactate and (13)C‐bicarbonate production were measured. Linear mixed‐effects regressions were performed to compute the regional percentage change per decade, showing a significant reduction in both normalized (13)C‐lactate and normalized (13)C‐bicarbonate production with age: [Formula: see text] per decade for (13)C‐lactate and [Formula: see text] per decade for (13)C‐bicarbonate. Certain regions, such as the right medial precentral gyrus, showed greater rates of change while the left caudate nucleus had a flat (13)C‐lactate versus age and a slightly increasing (13)C‐bicarbonate versus age. The results show that both the production of lactate (visible as (13)C‐lactate signal) as well as the consumption of monocarboxylates to make acetyl‐CoA (visible as (13)C‐bicarbonate signal) decrease with age and that the rate of change varies by brain region.