Menstrual phase-related differences in the pulsatility index on the central retinal artery suggest an oestrogen vasodilatation effect that antagonizes with progesterone

Abstract

Our results suggest the existence of an oestrogen vasodilatation effect on the central retinal artery that is menstrual phase-related and antagonized by progesterone.

Vascular resistance of central retinal artery is reduced in postmenopausal women after use of estrogen

“…Another study that evaluated the effect of ovarian steroids on the vascular resistance of the CRA also suggested the existence of an estrogen vasodilatation effect because a reduction in PI during the follicular phase of ovulatory women was observed. 16 Therefore, we performed this study to evaluate the effect of estrogen on the vascular resistance of the CRA in postmenopausal women, compared with placebo, using transorbital ultrasound with Doppler fluxometry. The results not only may increase our understanding of the effects of reproductive hormones on the central nervous system but can also help elucidate the pathogenesis of migraine, premenstrual syndrome, and loss of cognitive function and diseases, such as stroke and Alzheimer disease.…”

Vascular resistance of central retinal and ophthalmic arteries in postmenopausal women after use of tibolone

“…It has already been demonstrated that estradiol decreases the vascular resistance of cerebral vessels in premenopausal women 20 and thus increases resistance during menopause. 23,24 Therefore, only postmenopausal and nonobese women who were not using hormones were evaluated to avoid having the possible effects of endogenous estrogen cause any bias to the study.…”

“…25 We decided to study central retinal and ophthalmic arteries because they are functionally and anatomically identical to other cerebral arteries of a similar size. 26,27 In addition, the easy access allows the evaluation to be performed directly on the arterial vascular bed 19,20,28 and to be repeated by others.…”

“…20 Briefly, all women were examined while they were in a supine position and were instructed to keep both eyes closed to avoid ocular globe movements; a thin hydrosoluble gel layer was applied over each superior eyelid, right under the eyebrow, at the place where the transducer was positioned. Ultrasound was performed using a linear transducer (5-12 MHz) with a color Doppler filter of 50.0 Hz.…”

“…19 In addition, another study that evaluated the effect of ovarian steroids on vascular resistance of the central retinal artery (CRA) suggested the existence of an estrogen vasodilation effect because a reduction of vascular resistance was observed during the follicular phase in ovulatory women. 20 Doppler velocimetry of orbital vessels is feasible and reproducible and may reflect systemic changes in the cardiovascular system. The retinal artery is a branch of the ophthalmic artery that has its origin in the carotid artery; therefore, it is anatomically and functionally similar to the intracranial vessels of equal diameter.…”