Figure 1.

Route of nonesterified fatty acids from blood to the mitochondrial degradation in the brain. After dissociation of albumin-bound nonesterified fatty acids (NEFA) from albumin (indicated in yellow), NEFA migrate across the blood–brain-barrier (BBB). Thereafter, NEFA enter neural cells and are activated to acyl-CoA-derivatives in the cytosolic compartment. In the activated form, NEFA support either the biosynthesis of membrane lipids or the re-acylation of lysophospholipids. Alternatively, β-oxidation of acyl-CoA-derivatives in the mitochondria delivers the reducing equivalents nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH₂) for fueling the electron transport chain, which generates the electrochemical proton gradient, the driving force for energy-dependent ATP synthesis. CO₂ and H₂O are formed as degradation products of the β-oxidation of acyl-CoA-derivatives.