Lipids and antioxidative effects of estradiol and sequential norethisterone acetate treatment in a 3-month randomized controlled trial

The effect of 17β-estradiol plus norethisterone acetate treatment on lipoprotein (a), atherogenic and anti-atherogenic apolipoproteins levels in postmenopausal women: A meta-analysis of randomized controlled trials

BACKGROUND AND AIM

The administration of 17β-estradiol plus norethisterone acetate seems to confer women cardioprotection, however, its impact on lipoprotein (a) and apolipoproteins' concentrations remains unclear. Thus, we conducted a meta-analysis of randomized controlled trials (RCTs) to investigate the effect of 17β-estradiol plus norethisterone acetate treatment on lipoprotein (a) and apolipoproteins' values in females.

METHODS

We systematically searched four databases (PubMed/MEDLINE, Scopus, Embase, and Web of Science) to identify relevant publications published until March 9th, 2022. No language restrictions were applied. The random-effects model (the DerSimonian and Laird methods) was employed to calculate the weighted mean difference (WMD).

RESULTS

The administration of 17β-estradiol plus norethisterone acetate resulted in a significant decrease of lipoprotein (a) (WMD: -67.59 mg/L, 95 % CI: -106.39 to -28.80; P < 0.001) and apolipoprotein B concentrations (WMD: -3.71 mg/dL, 95 % CI: -6.68 to -0.75; P = 0.014), respectively. No effect of 17β-estradiol plus norethisterone acetate on apolipoprotein AI (WMD: 0.23 mg/dL, 95 % CI: -3.99 to 4.46; P = 0.91) or AII (WMD: 0.21 mg/dL, 95 % CI: -2.24 to 2.68; P = 0.86) concentrations was detected. In the stratified analysis, there was a notable reduction in lipoprotein (a) levels in the RCTs with a duration of ≥6 months (WMD: -73.34 mg/L), in postmenopausal women with a BMI ≥25 kg/m² (WMD: -69.85 mg/L) and in postmenopausal women aged ˂60 years (WMD: -61.93 mg/L).

CONCLUSION

The present meta-analysis of RCTs demonstrates that 17β-estradiol plus norethisterone acetate treatment reduces lipoprotein (a) and apolipoprotein B levels in postmenopausal women.

Effect of different contraceptive methods on the oxidative stress status in women aged 40 48 years from the ELAN study in the province of Liege, Belgium

BACKGROUND

Oxidative stress is associated with the development of several disorders including cardiovascular disease and cancer. Among conditions known to influence oxidative stress, the use of oral contraception (OC) in women has been a matter of ongoing discussion.

METHODS

A total of 897 eligible and healthy volunteers were recruited from among the patients of 50 general practitioners participating in the ELAN study (Etude Liégeoise sur les ANtioxydants). A subsample consisting of 209 women aged 40-48 years was studied for a comprehensive oxidative stress status (OSS), including the analysis of antioxidants, trace elements and three markers of oxidative damage to lipids. Among 209 subsample, 49 (23%) were OC users (OCU), 119 (57%) non-contraception users (NCU) and 41 (20%) were intrauterine (hormonal and copper) devices users (IUD).

RESULTS

After adjustment for smoking, systolic and diastolic blood pressure and BMI (or waist circumference), a marked and significant increase in lipid peroxides was observed among OCU women when compared with NCU and IUD users. A cut-off value of 660 microM in lipid peroxides allowed the discrimination of OCU from the two other groups. In contrast, no difference was observed in the plasma concentration of both oxidized low-density lipoprotein (LDL) and their related antibodies. The increased level in lipid peroxides was strongly related to higher concentrations of copper (r < 0.84; P < 0.0001, cut-off value 1.2 mg/l). When compared with NCU and IUD users, plasma antioxidant defences were significantly altered in OCU women as shown by lower levels of beta-carotene (decrease of 39%; P < 0.01) and gamma-tocopherol (decrease by 22%; P < 0.01). In contrast, higher concentrations of selenium (increased by 11.8%; P < 0.01) were observed in OCU women. Blood concentrations of vitamin C, alpha-tocopherol and zinc were unaffected by OC use.

CONCLUSIONS

The intake of OC significantly increases the lipid peroxidation in women aged 40-48 years. This may represent a potential cardiovascular risk factor for these women.

Biochemical markers surrogating on vascular effects of sex steroid hormones

The main mechanism of possible cardioprotection by estrogens appears to be a direct effect on the vasculature, resulting in an improvement of endothelial function and inhibition of atherogenesis. Numerous observational and experimental studies have demonstrated a positive correlation between estrogens and various biochemical markers surrogating direct vascular effects. In general, most markers are influenced in a similar way by oral and transdermal hormone therapy, although oral therapy may have a faster and more pronounced effect. The main difference between oral and transdermal administration may be confined to markers that are mainly or exclusively produced in the liver. Clinical studies demonstrate that progestogen addition can have an impact on the beneficial estrogen-induced changes of biochemical markers. Concerning the effects of tibolone, inconsistent data have been found. Overall, tibolone-induced beneficial changes on the various biochemical markers appear to be less marked compared with those of hormone therapy. The few data available on the direct effects of androgens on the vascular wall indicate a less favorable action of androgens on biochemical markers than of estrogens. The practical relevance of marker measurements is currently under discussion. Although evidence strongly supports some of these markers as predictors of acute events, it remains to be established whether modifying circulating levels of these markers will influence outcomes.