Estriol: emerging clinical benefits

Abstract

We conclude transvaginal estriol potentially offers a suitable physiologic delivery and cost-effective alternative to currently available estrogen regimens in selected patients. Additional studies on mode of delivery, safety, and efficacy merit further investigation.

Multiomic immune clockworks of pregnancy

“…For instance, while consistent evidence in humans and in the context of pregnancy is lacking, animal and in vitro models show that E2 inhibits the proliferation and cytotoxicity of NK cells [ 68 , 92 ], inhibits Th17 differentiation [ 129 , 130 , 134 , 176 , 186 ], and promotes the differentiation of peripheral Tregs [ 1 , 31 , 72 ]. Some studies have suggested that E3—which exists only during pregnancy—is capable of inhibiting nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB)-mediated transcription, although cell specificity has not been studied [ 4 , 196 ].…”

Treatment of genitourinary syndrome of menopause: the potential effects of intravaginal ultralow-concentration oestriol and intravaginal dehydroepiandrosterone on quality of life and sexual function

“…It is oxidised to oestrone and both oestradiol and oestrone can be converted to oestriol by the liver. Although oestriol bioavailability is higher than oestradiol because of its lower affinity for the sex hormone binding protein [59], oestriol has lower oestrogenic potency than oestradiol (ranging from 1 : 10 to 1 : 100) [60] and greater relative affinity for oestrogen receptor-β than for oestrogen receptor-α, thus minimising extravaginal effects [61]. For this reason, a sequential progesterone for endometrial protection can be omitted [59].…”

“…It is known that 0.5-1 mg intravaginal oestriol is well absorbed by an atrophic epithelium, and it is equivalent to oral doses of 8-12 mg [63]. Furthermore, oral oestriol administration is associated with entero-hepatic recirculation with prolonged exposure, whereas only 20% of oestriol applied intravaginally reaches the circulation [59]. Intravaginal oestriol improves symptoms of GSM, sexual health, and, more generally, women’s QoL [64].…”

“…However, the main concerns regarding oestrogen administration are side-effects, although few have been observed for intravaginal oestriol, and those that have are mainly local: irritation, burning sensation, itching, and leucorrhoea [71]. Furthermore, some studies have shown, on the basis of blood concentrations, that the profile for oestriol is safe because of its very low systemic bioavailability [66, 69], and no correlations have been found between intravaginal oestriol administration and increased endometrial thickness [59, 72].…”

Differences in the reaction of hyperlipidemia on different endothelial progenitor cells based on sex

“…These cytokines also promote hematopoietic cell development and function ( 22 ). Nevertheless, estrogen may act on estrogen receptors on EPCs to suppress the expression of genes related to pro-atherosclerosis, whilst promoting the expression of anti-atherosclerosis genes to downregulate proinflammatory cytokine expression ( 23 ).…”