Part 5. Please read the following article and answer the following questions source: Modified from NatureMetabolism 2, 1248-1264(2020)] In addition to fatty acids, glucose and lactate are important myocardiai substrates under physiologic and stress conditions. Theyare metabolized to pyruvate, which enters mitochondria via the mitochondrial pyruvate carricr (MPC) for citric acid cyclemctabolism. In the present study. we show that MPC-mediated mitochondrial pyruvate utilization is essential for the partitioning ofglucose-derived cytosolic metabolic intcrmediates. which modulate myocardial stress adaptation. Mice withcardiom yocyte-restricted deletion of subunit 1 of MPC (cMP

) developed age-dependent pathologic cardiac hypertrophy.transitioning to a dilated cardiomyopathy and premature death. Hypertrophied hearts accumulated lactate. pyruvate and glycogen,and displayed increased protein O-linked N-acetylglucosamine, which was prevented by increasing availability of non-glucosesubstrates in vivo by a ketogenic diet (KD) or a high-fat diet, which reversed the structural. metabolic and functional remodelling ofnon-stressed cMP

 hearts. Although concurrent short-term KDs did not rescue cMPCI

 hearts from rapid decompensation andcarly mortality after pressure overload, 3 weeks of a KD before transverse aortic constriction was sufficient to rescue this phenotype.Together. our results highlight the centrality of pyruvate metabolism to myocardial metabolism and function.
【題組】19. The phrase "in addition to" is closest in meaning to? (3%)
(A) Unlike
(B) As long as
(C) Besides
(D) On the contrary