Menopause, the Cardiovascular Risk Factor Homocysteine, and the Effects of Treatment

Hyperhomocysteinemia as a Risk Factor and Potential Nutraceutical Target for Certain Pathologies

Hyperhomocysteinemia is recognized as a risk factor for several diseases, including cardiovascular and neurological conditions. Homocysteine (HCys) is a key metabolite involved in the biosynthesis and metabolism of methionine (Met), which plays a pivotal role in the physiological cell's life cycle. The biochemistry of Met is finely regulated by several enzymes that control HCys concentration. Indeed, balanced activity among the enzymes is essential for the cell's well-being, while its malfunction could raise HCys concentration which can lead to the onset of several pathological conditions. The HCys concentration increase seems to be caused mainly by the widely diffused polymorphisms of several enzymes. Nowadays, a blood test can easily detect elevated concentrations of HCys, referred to as Hyperhomocysteinemia (HHCys). Prolonged exposure to this condition can lead to the onset of cardiovascular disease and can lead to the development of atherosclerosis, stroke, inflammatory syndromes like osteoporosis and rheumatism, as well as neuronal pathologies including Alzheimer's and Parkinson's diseases. In this review, we analyzed the literature of several pathological conditions in which the molecular pathways of HHCys are involved. Interestingly, several observations indicate that the calibrated assumption of correct doses of vitamins such as folic acid, vitamin B6, vitamin B12, and betaine may control HHCys-related conditions.

Folic acid supplementation reduces plasma homocysteine in postmenopausal women

Plasma homocysteine, which is increased after menopause, can be a risk factor for cardiovascular disease and osteoporosis. The purpose of the present study was to determine the effect of folic acid supplementation on plasma homocysteine in postmenopausal women. The study was performed as a randomized placebo controlled trial on 48 healthy postmenopausal women (aged 50-70 years) and plasma homocysteine of all women was measured. In the case group, folic acid, and in the control group, placebo was prescribed. The second plasma homocysteine was measured 16-17 weeks later and was compared in the two groups. There was no significant difference between the two groups according to age, BMI, parity, duration of menopause and the first plasma homocysteine level. Plasma homocysteine level was significantly lower in the case group than control group 16 weeks after folic acid administration (10.33 ± 3.51 μmol/l vs 13.21 ± 3.11 μmol/l, p=0.004). There was no significant correlation between plasma homocysteine level and BMI and parity. However, there was a weak-moderate positive correlation between plasma homocysteine and age (p<0.05, r=0.33), and there was a significant but weak correlation between plasma homocysteine and duration of menopause (p=0.05, r=0.28).

A comparison of the effects of sequential transdermal versus continuous orally administered hormone replacement therapies on plasma total homocysteine levels in postmenopausal women: A randomized, placebo-controlled study

OBJECTIVE

The objective was to determine the effects of transdermal and oral hormone replacement therapies on plasma total homocysteine levels in postmenopausal women.

MATERIAL AND METHODS

One hundred and ten postmenopausal patients were enrolled in the study. Participants were randomized into three groups: in Group A (n = 31) oral continuous combined therapy and in Group B (n = 30) transdermal sequential hormone replacement therapy were given for 6 months. A placebo was administered orally to the control group (Group C, n = 30). Serum homocysteine levels were studied prior to and after 6 months of treatment in all groups.

RESULTS

There were no statistical significant differences in mean serum homocysteine levels among the groups prior to the study. The mean homocysteine levels after 6 months in Groups A-C were also similar.

CONCLUSIONS

Serum homocysteine levels alter with neither oral continuous nor sequential transdermal hormone replacement therapy.

The Cardiovascular Effects of Selective Estrogen Receptor Modulators

Coronary artery disease (CAD) is the main contributor of mortality among postmenopausal women. Menopause-associated estrogen deficiency has both metabolic and vascular consequences that increase the risk for CAD. Hormone therapy (HT) has been reported to have a beneficial effect on metabolic and vascular factors influencing the incidence of CAD. Although observational studies have reported that HT reduces significantly the risk for CAD, randomized clinical trials (WHI, HERS, ERA) have questioned the efficacy of HT in primary and secondary CAD prevention despite confirming the lipid-lowering effect of HT. In the aftermath of the WHI, increased interest has been given to the action of selective estrogen receptor modulators (SERMs) and their effect on the cardiovascular system. The chemical structure of SERMs, either triphenylethilyn (tamoxifen) or benzothiophene (raloxifene) derivatives, differs from that of estrogens. SERMs are nonsteroidal molecules that bind, with high affinity, to the ER. SERMs induce conformational changes to the ligand-binding domain of the ER that modulate the ability of the ER to interact with coregulator proteins. The relative balance of coregulators within a cell determines the transcriptional activity of the receptor-ligand complex. SERMs therefore may express an estrogen-agonist or estrogen-antagonist effect depending on the tissue targeted. SERMs express variable effects on the metabolic and vascular factors influencing the incidence of CAD. SERMs have been reported to modulate favorably the lipid-lipoprotein profile. Toremifene expresses the most beneficial effect followed by tamoxifene and raloxifene, while ospexifene and HMR-3339 have the least effect and may even increase triglycerides. Raloxifene and tamoxifene decrease serum homocysteine levels and C-reactive proteins (CRP), which are both markers of CAD risk. Raloxifene has been reported to increase the nitric oxide (NO)-endothelin (ET)-1 ratio and, thus, contribute to proper endothelial function and vasodilation. Toremifene has no effect on the NO-ET-1 ratio. Finally, raloxifene decreases the vascular cell adhesion molecules and the inflammatory cytokines TNF-alpha and IL-6. Of the SERMs, raloxifene has had the most extensive evaluation regarding the effect on the vascular wall of endothelium. Although not confirmed by large clinical trials, raloxifene has been reported to have an effect on the cohesion of the intercellular junction (VE-cadherin) and the synthesis-degradation of extracellular matrix (MMP-2). The Multiple Outcomes Raloxifene Evaluation (MORE) study has reported that raloxifene may have a cardioprotective effect when administered to postmenopausal women at high risk for CAD disease.