臍帯血におけるapo E分布の特異性

抄録

The profile of the distribution of apo E into lipoproteins (apo E profile) had been acquired by author's method that immune complex of apo E was stained after agarose gel-immunofixation electrophoresis using anti-apo E serum. And it had been revealed that apo E distributed in pre-β, β lipoprotein and apo E-containing high-density lipoprotein (HDL-with apo E) which migrated to near the α₂-globulin region between pre-β lipoprotein and α lipoprotein, and apo E in HDL-with apo E determined by this method had been named “α₂-apo E”.
In this paper, lipids, apolipoproteins and apo E profile were determined in 10 normal full-term female infants and 10 healthy female adults, in order to characterize the distribution of apo E in umbilical cord serum. The whole serum apolipoprotein levels in mg/dl±S. D. for all neonates were; apo A-I=84.4±11.8; apo B=14.0±4.2; apo E=3.7±1.2. These values represented 62.5% and 15.9% of adult serum values for apo A-I and apo B, respectively, with normal adult values for apo E. The umbilical values of total cholesterol and cholesterol in HDL (HDL-C) represented 31.7% and 81.2% of adult values, and HDL-C represented 60% of total cholesterol in cord serum. The umbilical activity of LCAT represented 26.7% of adult activity, however the cholesterol esterification ratio (esterified cholesterol×100/total cholesterol, %) did not differ between cord serum and adult serum.
Apo E profile in umbilical cord serum was characterized by the distribution of the majority of apo E to HDL-with apo E, so α₂-apo E concentration and α₂-apo E ratio (α₂-apo E×100/total apo E, %) were significantly high levels of 3.3±1.2mg/dl and 90.6±4.5% in cord serum, in contrast to the levels of 2.0±0.4mg/dl and 50.1±8.0% in adult serum. And in cord serum, α₂-apo E was significantly correlated with total cholesterol (r=0.720, p<0.01) and with HDL-C (r=0.688, p<0.01), and α₂-apo E ratio reversely correlated with apo B (r=-0.660, p<0.05). So these data suggested the important relationship between α₂-apo E and cholesterol metabolism in neonates whose apo B-containing lipoproteins that must transport cholesterol to tissues decreased, in consideration of Innerarity's report suggested that neonates might depend (at least in part) upon HDL-with apo E to deliver to tissues via LDL-receptor.
Then, umbilical apo E profile was similar to apo E profiles acquired from patients with acute hepatitis or severe hyperthyroidism. But the reduction of HDL-C and reverse correlation between α₂-apo E and HDL-C in acute hepatitis were not recognized in cord serum, and umbilical levels of thyroxine and free thyroxine were in normal adult levels. In conclusion, umbilical cord serum was characteristic of the superiority of HDL to apo B-containing lipoproteins in its content, especially apo E distributed for the most part in HDL, being reflected in reduction of apo B-containing lipoproteins.