Human Reproduction vol.13 no.6 pp.1449–1454, 1998 The effect of oestrogen on intimal hyperplasia in

1To whom correspondence should be addressed The beneficial effect of oestrogen on blood vessels may include modulation of vascular response to injury. In this experiment we set out to develop an in-vitro model, using all human materials, for the study of vascular changes in culture, and their response to oestrogen treatment. Human ovarian vein segments were obtained from 15 hysterectomy specimens, and cultured with and without the addition of 17b-oestradiol. Paired control veins were cultured with the inert 17a-oestradiol. The veins were stained with anti-a-smooth muscle actin and Miller’s elastin, and intimal thickness measured. Cultured veins developed a significant degree of intimal thickening [15.7 versus 8.25 mm in fresh veins, 95 % confidence intervals (CI) 13.6, 17.8 and 6.3, 10.2 respectively; P 5 0.0001]. The addition of 17b-oestra-diol, but not 17a-oestradiol, led to a significant reduction in intimal hyperplasia (intimal thickness 8.85 mm; 95 % CI 6.9, 10.8; P 5 0.008). The mean number of nuclei per high-power field was also significantly lower in the intima of oestrogen-treated compared to untreated veins (11.6; 95% CI 9.9, 13.26 versus 14.05; 95 % CI 12.5, 15.6; P 5 0.001). Our data suggest that intimal hyperplasia in cultured ovarian veins is effectively reduced by oestrogen. Key words: cultured human ovarian veins/intimal hyperplasia/ oestrogen/postmenopausa