Relationship between lipid metabolism and plasma concentration of amyloid precursor protein and apolipoprotein E

Alzheimer's disease is characterised by the deposition in the brain of a 4kDa peptide, termed βamyloid, a proteolytic product of the amyloid precursor protein (APR). The e4 allele of apolipoprotein E (apoE), lipid transport protein, has been identified as a major genetic risk factor for Alzheimer's disease, thereby implicating lipid-orientated metabolic processes in the development of this disease. Recent research has established a possible link between APP and apoE. Therefore, in order to establish whether fat metabolism affects APP production and/or clearance, we examined the levels of plasma APP and apoE in control subjects, following intake of a high-fat, low carbohydrate drink. An increase in both plasma APP and apoE concentrations was observed, concomitant with an increase in blood triglycéride concentration in all subjects. In addition, there was a significant correlation between fasted blood cholesterol and plasma APP. Thus we conclude that ingestion of fat alters plasma APP and apoE levels and that the status of fasting blood cholesterol levels may be reflected in APP levels. Further extended and longitudinal studies are warranted to determine the physiological and pathological significance of this diet-induced change in plasma APP and apoE levels.