From the Guidelines
The Krebs cycle can be simplified as a series of chemical reactions that convert citrate into energy, producing ATP, NADH, and FADH2, with citrate being a key intermediate metabolite that does not require insulin to enter cells and can be metabolized yielding energy and bicarbonate 1.
Key Components of the Krebs Cycle
- The cycle begins with citrate, which is an intermediate metabolite that can be derived from various sources, including the metabolism of carbohydrates, fats, and proteins.
- Citrate is metabolized in the liver, kidney, and skeletal muscle, and its metabolism yields energy and bicarbonate 1.
- The Krebs cycle produces high-energy electron carriers, such as NADH and FADH2, which are then used to generate ATP in the electron transport chain.
- The cycle also regenerates oxaloacetate, allowing it to continue and produce more energy.
Clinical Relevance of the Krebs Cycle
- In patients undergoing kidney replacement therapy (KRT), the Krebs cycle can be impacted by the delivery of energy substrates, such as citrate, lactate, and glucose, from dialysis/hemofiltration solutions 1.
- The metabolism of citrate in the Krebs cycle can provide a substantial amount of energy, with one study reporting up to 1300 kcal/d using high lactate replacement fluids and anticoagulation with ACD-A 1.
- Therefore, it is essential to consider the energy provision from these sources when calculating the total daily energy provision for patients undergoing KRT to avoid overfeeding 1.