Yc. Wen et al., Combined oestrogen-progestogen replacement therapy does not inhibit low-density lipoprotein oxidation in postmenopausal women, BR J CL PH, 47(3), 1999, pp. 315-321
Aims The use of oestrogen containing hormone replacement therapy (HRT) is r
elated to a significantly reduced atherosclerotic cardiovascular risk in po
stmenopausal women. Oestrogen is thought to be antioxidant and may inhibit
low-density lipoprotein (LDL) oxidation in vitro. We investigated the effec
t of combined oestrogen and progestogen HRT on LDL oxidation in postmenopau
sal women.
Methods Eighteen healthy women were given oestrogen/progestogen, and the su
sceptibility of LDL to oxidation was measured as the level of autoantibody
to oxidative modified LDL and the production of conjugated dienes during co
pper-dependent oxidation after 3 and 6 months HRT. The levels of vitamin E,
the major antioxidant in LDL, were also measured.
Results After HRT, the anti-oxidatively modified LDL antibody level remaine
d unchanged [1.58+/-0.16, 0.10 (-0.10, 0.26), and 0.08 (-0.09, 0.19), mean/-s.d. at baseline, and mean change with 95% confidence intervals for diffe
rences at 3 and 6 months, respectively, P>0.05] as did the production of co
njugated dienes when determined as lag phase [51.2+/-7.5, -0.3 (-3.9, 3.3),
and 1.5 (-3.4, 6.4) min, P>0.05]. The LDL vitamin E content, measured as a
lpha-tocopherol, was also not altered [2.34+/-0.54, -0.07 (-0.27, 0.13), an
d -0.07 (-0.33, 0.16) nmol mg(-1) LDL, P>0.05] by treatment.
Conclusions Combined oestrogen and progestogen therapy for 6 months in post
menopausal women does not protect LDL against oxidation.