Phytosterols in aortic tissue in adults and infants.
Relationships between aortic tissue phytosterols and cholesterol in five adults, five infants, two neonates, and one 30 week abortus were studied. In the normal aortic tissue of the abortus and two neonates, tissue cholesterol levels were 0.67, 0.08, and 0.89 mg. per gram of wet weight, respectively; tissue phytosterol levels were as follows: compesterol (0.94, 0.62. 1.8), stigmasterol (0.18, 0.54, 0.80) and beta-sitosterol (0.78, 1.84, 2.80) mug per gram of wet weight. In 11 aortic tissue samples from five infants studied at 3, 4, 6, 6, and 36 months of age, all having been on phytosterol-rich formulas, mean aortic cholesterol was 0.66 mg. per gram, campesterol 3.57, stigmasterol 9.22, and beta-sitosterol 8.93 mug per gram. In the 11 aortic samples from five infants, mean (+/-S.E.) tissue stigmasterol (9.2+/-2.7) and beta-sitosterol ((8.9+/-1.3) were greater than mean levels (0.51+/-0.18 and 1.8+/-0.6) in the four aortic sections from the abortus and two neonates. Mean (+/-S.E.) cholesterol in the 11 aortic sections from five infants (0.66+/-0.11) was not significantly higher than cholesterol (0.55+/-0.24 mg. per gram) in the four aortic sections from the abortus and two neonates, but was considerably higher than the tissue cholesterol level of 0.08 mg. per gram in one of the two neonates. Mean (+/-S.E.) cholesterol in 11 normal aortic tissue sections from five adults (3.4+/-0.7 mg. per gram) was higher than in the five infants, whereas mean compesterol, stigmasterol, and beta sitosterol, respectively 14, 13, and 16 mug per gram, were somewhat higher but generally comparable to infant levels. In five aortic tissue samples from mature atheromatous plaques in two adults, cholesterol was 54 mg. per gram and mean campesterol, stigmasterol, and beta-sitosterol were, respectively, 112, 167, and 236 mug per gram. In 15 aortic tissue samples from five adults, cholesterol correlated closely with stigmasterol, r=0.865, beta-sitosterol, r=0.918, and with total phytosterols, r=0.938, p less than 0.01, but not with campesterol, r=0.448. In 11 aortic tissue samples from five infants, cholesterol did not correlate with campesterol, r=0.005, stigmasterol, r=0.006, beta-sitosterol, r=-0.099, or total phytosterols, r=-0.045. Prior to birth some phystosterols apparently cross the placenta. In the first several months of life, vegetable-oil formula-fed infants accrue plant sterols in their aortic tissues. Moderate amounts of phytosterols are present in mature atheromatous lesions in adults. The implications of these findings are unknown and their relationship to deposition of cholesterol in atheromatous and in normal aortic tissues remains to be elucidated.