Anaplerotic molecules: current and future.

This review presents the concepts of anaplerosis and cataplerosis in relation to the regulation of citric acid cycle operation. Anaplerosis is the re-filling of the catalytic intermediates of the cycle that carry acetyl-CoA as it is oxidized. The main anaplerotic substrates are pyruvate, glutamine/glutamate and precursors of propionyl-CoA (odd-chain fatty acids, specific amino acids, C(5)-ketone bodies). Cataplerosis balances anaplerosis by removing excess intermediates from the citric acid cycle. The properties of the main anaplerotic substrates are reviewed from the point of view of potential clinical applications to the treatment of some inherited and acquired conditions.