In vivo investigation of recuperation dynamics of altered myocardial PDH activity induced by a ketogenic diet

Motivation: Metabolic alterations associated with a ketogenic diet (KD) include suppressed carbohydrate utilization in the myocardium, but how quickly they recover by reverting to a normal diet (ND) is under-investigated. Goal(s): This study investigates recuperation dynamics of myocardial pyruvate oxidation by reverting a KD to a ND. Approach: Cardiac metabolism of healthy rats was longitudinally assessed using hyperpolarized [1-13C]pyruvate at baseline, during a KD, and a subsequent ND after the 5-week KD. Results: Cardiac [13C]bicarbonate disappeared with a KD. Reverting to ND gradually recovered the PDH flux over eight days. [1-13C]Lactate production in the KD group showed the opposite but similar dynamic patterns. Impact: Compensating the metabolic shifts by a ketogenic diet is challenged for proper assessment of cardiac metabolism and is often attempted by temporarily reverting the diet. Understanding the recuperation dynamics is crucial in proper assessment of cardiac metabolism.