Pe. Pajukanta et al., THE EFFECTS OF THE APOLIPOPROTEIN-B SIGNAL PEPTIDE (INS DEL) AND XBAIPOLYMORPHISMS ON PLASMA-LIPID RESPONSES TO DIETARY CHANGE/, Atherosclerosis, 122(1), 1996, pp. 1-10
There is interindividual variation in plasma lipid response to dietary
changes. The polymorphisms which are associated with plasma lipid lev
els could possibly explain part of this variation. Therefore, the apol
ipoprotein B (apo B) signal peptide insertion/deletion (ins/del) and X
baI restriction fragment length polymorphisms are possible regulators
of plasma lipid responses. We examined their role in the regulation of
plasma lipid responses in 87 North Karelians (43 men, 44 women). The
dietary study consisted of a 2-week baseline period (34-35% of energy
from fat), followed by an 8-week low-fat (24 En%), low-cholesterol (27
9 mg/d) diet period and an 8-week switchback period. In this study pop
ulation the apo B ins/del and XbaI polymorphisms exhibited mainly simi
lar and partly significant effects on the responses of plasma very low
-density lipoprotein (VLDL) and high density lipoprotein(2) (HDL(2)) c
holesterol to dietary changes. After consumption of the low saturated
fat, low-cholesterol diet, ins/ins and X-/X- homozygotes showed the gr
eatest increase in VLDL cholesterol (p < 0.05 for differences between
ins/del genotypes) and the greatest fall in HDL(2) cholesterol (p = 0.
01 for ins/del and p = 0.05 for XbaI), while only minimal alterations
were seen in the del/del and X+/X+ groups. After returning to the orig
inal diet, the changes of these lipids were reversed, ins/ins and X-/X
- homozygotes having the greatest reductions in VLDL cholesterol (p <
0.05 for XbaI) and the greatest increases in HLDL(2) cholesterol (p <
0.001 for XbaI). The findings suggest that plasma VLDL and HDL(2) chol
esterol responsiveness to diet may be partly explained by variation at
the apo B gene.