Studies on the role of high density lipoprotein subfractions : applications to peripheral vascular disease and Alzheimer's disease
The present work was performed in order to study the role of specific subfractions of HDL and their applications in peripheral vascular disease and Alzheimer's disease. The results may be summarized as follows: 1. There were no significant differences observed in the concentration of total plasma cholesterol, VLDL-cholesterol, LDL-cholesterol and HDL-cholesterol when 19 female AD patients were compared with 19 female control subjects. There were, however, some observed differences in the HDL subfractions between the two groups, with the Alzheimer patients having a significantly lower level of HDL2b and a corresponding higher level of HDL3a. 2. The female Alzheimer patients had a significantly higher frequency of the apo E ε4 allele compared with the control subjects. 3. In a comparison of 63 male patients with peripheral vascular disease and 63 healthy male control subjects, no significant difference was observed in the concentration of total plasma cholesterol. The patients, however, had a significantly higher VLDL-cholesterol concentration with significantly lower LDL- and HDL-cholesterol concentrations. Consequently, the CRI was significantly higher in patients. The patients also had significantly lower levels of the larger HDL2 particles (HDL2b and HDL2a) with corresponding higher levels of the smaller HDL3 particles (HDL3a and HDL3c). 4. After treatment for 6 months with GLA and the antioxidants, β-carotene and ascorbate, only the double placebo group showed a difference with a significant rise in LDL-cholesterol concentration. This result indicates that both GLA and the antioxidants have to be present in order to prevent a rise in atherogenic LDL. 5. The thesis describes the value of studies on HDL subfractions in the development of disease.