Plasma Proteins and Serum Lipoproteins in Relation to Cardiovascular Disease
ULTRACENTRIFUGAL and electrophoretic technics provide means of characterizing, quantitating, and isolating proteins and lipoproteins of body fluids and tissues. Through investigation of plasma proteins and lipoproteins in experimental animals, in normal human beings of different racial and age groups, and in patients with various metabolic diseases before and after treatment, some understanding of the factors involved in maintaining normal plasma protein and lipoprotein patterns has been obtained.
The plasma protein fractions resolved by free-moving boundary or paper-electrophoretic technics at pH 8.6 are conventionally designated in the order of decreasing mobility: albumin, α1, α2, β, ϕ, and γ-globulins. All serum cholesterol is found in the lipoproteins that are fractions of the α- and β-globulins. The α and β lipoproteins have been extensively studied by ultracentrifugal technics.1
In some species atherosclerosis can be produced readily, while other species are resistant to the disease. A comparison of the serum lipoprotein patterns and cholesterol concentrations among various species showed that, in the dog, in which atherosclerosis is produced with difficulty, a large part of the lipid is found in the α-lipoprotein, while the β-lipoprotein concentration is low.1 The rat, which has a low concentration of serum cholesterol and of α- and β-lipoproteins, is also resistant to development of atherosclerosis. The serum lipoprotein pattern of swine has some characteristics similar to that of the human, with relatively high concentrations of β-lipoprotein and of low-density β-lipoprotein. Swine is a species in which atherosclerosis occurs spontaneously. The lipoprotein patterns of various strains of miniature swine fed the . . .