Age-associated change in pyruvate metabolism investigated with hyperpolarized C-MRI of the human brain.

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