Menopausal hormone therapy and coronary heart disease: the roller-coaster history.

In the USA it is estimated that more than one million women become menopausal each year. Coronary heart disease (CHD) is the leading cause of mortality in menopausal woman globally. The majority of perimenopausal to postmenopausal women experience bothersome symptoms including hot flashes, night sweats, mood liability, sleep disturbances, irregular bleeding and sexual dysfunction. While menopausal hormone therapy (HT) effectively treats most of these symptoms, use of HT has become confusing, especially related to CHD risk. Despite years of observational and retrospective studies supporting a CHD benefit and improved survival among HT users, the Heart and Estrogen/Progestin Replacement Study (HERS) and the Women's Health Initiative (WHI) raised doubts about this long-held premise. The timing hypothesis has since emerged and states that when HT is initiated in younger women, soon after menopause onset, there may be cardiovascular benefit. The following review discusses the roller-coaster history of HT use as it pertains to CHD in postmenopausal women. Studies that highlight HT's CHD benefit are reviewed and provide reassurance that HT utilized in appropriately selected younger postmenopausal women close to the onset of menopause is safe from a cardiovascular perspective, in line with consensus recommendations.

Hormone replacement therapy - where are we now?

Hormone replacement therapy (HRT) was the standard of care for menopause management until 2002, when perceptions changed following release of the initial results from the Women's Health Initiative (WHI) trial. Fears of breast cancer and heart attacks engendered by that report were not supported by the data, especially for recently menopausal women. Clinically, HRT is usually initiated near menopause. The WHI tested something different - the effects of HRT started a decade or more after menopause. As it turned out, age at starting HRT is critical in determining benefit/risk. HRT use plummeted following the WHI in 2002 and has remained low, prompting strong interest in alternative treatments. None provide the range of benefits across multiple organ systems offered by estrogen. Most have concerning adverse effects in their own right. HRT can provide effective relief for a wide range of health conditions, potentially avoiding the need for multiple treatments for separate problems. Unfortunately, among many women and clinicians, the perception of HRT benefit/risk is distorted, and its use avoided, leading to unnecessary distress. Following the WHI, many clinicians have not received adequate training to feel comfortable prescribing HRT. When initiated within 10 years of menopause, HRT reduces all-cause mortality and risks of coronary disease, osteoporosis, and dementias.

Determinants of attained estradiol levels in response to oral estradiol plus progesterone therapy.

OBJECTIVES: Among postmenopausal women taking hormone therapy (HT), the estradiol (E2) dose and E2 levels were differentially associated with change in metabolic measures. We evaluated determinants of attained E2 levels in response to HT. METHODS: Postmenopausal women from the REPLENISH trial tested four formulations of oral combined E2 and progesterone compared with placebo. Mixed-effects linear models assessed characteristics associated with E2 levels among women with ≥80% HT compliance, adjusted for E2 dose and baseline E2 level. RESULTS: Among 1173 postmenopausal women with mean (standard deviation) age 55 (4.3) years and 5.2 (4.8) years since menopause, higher treated E2 levels were significantly related to younger age, more recent menopause, and current alcohol use, while lower E2 levels were related to current smoking. Both age and time since menopause were significantly inversely associated with E2 levels; time since menopause had a stronger association with E2 levels. In the final multivariable model, E2 levels were positively associated with current alcohol use, and inversely associated with time since menopause and current smoking. CONCLUSION: Adjusting for E2 dose and baseline E2 level, on-trial E2 levels were significantly associated with time since menopause, current smoking, and current alcohol use. Practitioners should consider these factors in individual women to achieve a desirable E2 level during HT.

Association of oral estradiol dose/levels with coagulation measures in early/late postmenopausal women.

Objective: This study evaluated associations of estradiol (E2) dose and serum E2 levels with coagulation/anti-coagulation measures in early (<6 years) compared with late (≥10 years) postmenopausal women.Methods: Postmenopausal women from the REPLENISH trial tested four formulations of oral combined E2 and progesterone compared with placebo. Mixed-effects linear models tested the association of E2 dose and serum E2 levels with the prothrombin time (PT), the activated partial thromboplastin time (APTT), antithrombin (ATHRM), fibrinogen (FIBRINO), protein C (PROTC), and protein S (PROTS), assessed five times over 12 months.Results: Among 1215 early and 297 late postmenopausal women, the E2 dose was statistically significantly inversely associated with the APTT in early postmenopause, PROTC in late postmenopause, and with the PT, ATHRM, and PROTS in both groups. Serum E2 levels were statistically significantly inversely associated with the APTT, PROTS, and FIBRINO in early postmenopause, the PT in late postmenopause, and ATHRM and PROTC in both groups. With longer time since menopause, the inverse E2 dose effect and serum E2 effects became stronger.Conclusion: Increasing E2 dose and serum E2 levels were associated with changes in coagulation/anti-coagulation measures. The associations were stronger among women ≥10 years since menopause when initiating E2. The timing of E2 therapy, E2 dose, and serum E2 levels relative to time since menopause may modify the venous thromboembolism risk.

Hierarchical measurement structure in the Women's Health Questionnaire: a confirmatory factor analysis.

Purpose: This study conducted confirmatory factor analysis (CFA) to examine the measurement structure of the Women's Health Questionnaire (WHQ) and how its components were organized. Methods: Participants were 448 postmenopausal women, with a mean age of 63.3 years. CFA was conducted to test how well several proposed measurement models fit the data. Results: The single-factor model performed poorly, indicating the presence of multiple factors. The model with seven correlated factors fit the data well, although the varying degrees of inter-factor correlations suggested grouping of similar factors. The hierarchical measurement structure, with seven first-order factors organized under two second-order factors of physical health and mental health functioning, demonstrated a good fit with the data (χ2(367) = 694.05, p < 0.001; root mean square error of approximation = 0.05; comparative fit index = 0.95) and a meaningful pattern. The Mental Health factor was represented by Depressed Mood, Anxiety/Fear, Memory/Concentration Problems, and Sleep Problems. The Physical Health factor was manifested mainly by Somatic Symptoms, Menstrual Symptoms, and Vasomotor Symptoms, and, to a lesser extent, also by Sleep Problems and Memory/Concentration Problems. Conclusion: Findings suggested that, in addition to a global index and subscale scores, the WHQ may produce summary scores of physical health and mental health functioning in evaluation of well-being among postmenopausal women.

Menopausal hormone therapy and breast cancer: what is the evidence from randomized trials?

The relationship between menopausal hormone therapy (HT) and breast cancer is complex and further complicated by misinformation, perception, and overgeneralization of data. These issues are addressed in this mini-review through the lens of the Women's Health Initiative (WHI) that has colored the view of HT and breast cancer. In the WHI, unopposed conjugated equine estrogen (CEE) reduced breast cancer risk and mortality. In the WHI CEE plus continuously combined medroxyprogesterone acetate (MPA) trial, although the hazard ratio (HR) was elevated it was statistically non-significant for an association between CEE + MPA and breast cancer. In fact, the increased HR was not due to an increased breast cancer incidence rate in women randomized to CEE + MPA therapy but rather due to a decreased and unexpectedly low breast cancer rate in the subgroup of women with prior HT use randomized to placebo. For women who were HT naïve when randomized to the WHI, the breast cancer incidence rate was not affected by CEE + MPA therapy relative to placebo for up to 11 years of follow-up. The current state of science indicates that HT may or may not cause breast cancer but the totality of data neither establish nor refute this possibility. Further, any association that may exist between HT and breast cancer appears to be rare and no greater than other medications commonly used in clinical medicine.

Menopausal hormone therapy for primary prevention: why the USPSTF is wrong.

The US Preventive Services Task Force (USPSTF) Draft Recommendation statement on Menopausal Hormone Therapy: Primary Prevention for Chronic Diseases, released in May 2017, perpetuates a major disconnect between the primary population affected, women within roughly 10 years of menopause, and the data cited. Furthermore, major elements of the evidence relied upon have been misinterpreted or misstated, particularly in regard to coronary heart disease and breast cancer, for which there is no statistically significant evidence of harm. As currently drafted, the recommendations reiterate the USPSTF statements of 2012, 2005 and 2002, and will perpetuate egregious harm to the public health. In an attempt to avoid that outcome and to facilitate a return to rational discourse regarding menopausal hormone therapy, an ad hoc group of experts in menopausal health submitted this comprehensive response to the USPSTF.

Prevention of diseases after menopause.

Women may expect to spend more than a third of their lives after menopause. Beginning in the sixth decade, many chronic diseases will begin to emerge, which will affect both the quality and quantity of a woman's life. Thus, the onset of menopause heralds an opportunity for prevention strategies to improve the quality of life and enhance longevity. Obesity, metabolic syndrome and diabetes, cardiovascular disease, osteoporosis and osteoarthritis, cognitive decline, dementia and depression, and cancer are the major diseases of concern. Prevention strategies at menopause have to begin with screening and careful assessment for risk factors, which should also include molecular and genetic diagnostics, as these become available. Identification of certain risks will then allow directed therapy. Evidence-based prevention for the diseases noted above include lifestyle management, cessation of smoking, curtailing excessive alcohol consumption, a healthy diet and moderate exercise, as well as mentally stimulating activities. Although the most recent publications from the follow-up studies of the Women's Health Initiative do not recommend menopause hormonal therapy as a prevention strategy, these conclusions may not be fully valid for midlife women, on the basis of the existing data. For healthy women aged 50-59 years, estrogen therapy decreases coronary heart disease and all-cause mortality; this interpretation is entirely consistent with results from other randomized, controlled trials and observational studies. Thus. as part of a comprehensive strategy to prevent chronic disease after menopause, menopausal hormone therapy, particularly estrogen therapy may be considered as part of the armamentarium.

The timing hypothesis for coronary heart disease prevention with hormone therapy: past, present and future in perspective.

Over the past decade, two informative events in primary prevention of coronary heart disease (CHD) have occurred for women's health. The first concerns hormone replacement therapy (HRT) where data have come full circle from presumed harm to consistency with observational data that HRT initiation in close proximity to menopause significantly reduces CHD and overall mortality. The other concerns sex-specific efficacy of CHD primary prevention therapies where lipid-lowering and aspirin therapy have not been conclusively shown to significantly reduce CHD and, more importantly, where there is lack of evidence that either therapy reduces overall mortality in women. Cumulated data support a 'window-of-opportunity' for maximal reduction of CHD and overall mortality and minimization of risks with HRT initiation before 60 years of age and/or within 10 years of menopause and continued for 6 years or more. There is a substantial increase in quality-adjusted life-years over a 5-30-year period in women who initiate HRT in close proximity to menopause, supporting HRT as a highly cost-effective strategy for improving quality-adjusted life. Although primary prevention therapies and HRT contrast in their efficacy to significantly reduce CHD and especially overall mortality in postmenopausal women, the magnitude and types of risks associated with HRT are similar to those associated with other medications commonly used in women's health. The cumulated data highlight the importance of studying the HRT cardioprotective hypothesis in women representative of those from whom the hypothesis was generated.

HRT and breast cancer risk: a realistic perspective.

A new analysis from the Women's Health Initiative included data on breast cancer incidence over a 11-year period from the randomized trial of conjugated equine estrogens (CEE) plus medroxyprogesterone acetate (MPA) and a subsequent observational follow-up. The conclusions were that CEE/MPA use was associated with an increase in both breast cancer incidence and mortality. We have concerns over the validity of their statistical analyses, as adjustments for baseline characteristics or for multiple comparisons demonstrate no significant differences in incidence between those allocated to CEE/MPA or placebo. We suspect that the apparent increase in mortality is the result of surveillance and detection bias rather than a true cause and effect. Even if such an effect were true, mortality from breast cancer would still be a very rare event. We also question the clinical relevance and applicability of their findings. The data over the 11 years show no increased risk of breast cancer with CEE/MPA in women who had not previously used hormone replacement therapy (HRT), and the vast majority of women on HRT would not be prior users at initiation. It should be remembered that women using CEE alone showed a significant decrease in breast cancer risk in the WHI trial and follow-up. Even if combined estrogen?progestogen HRT did cause an increase in breast cancer risk, and this is not proven, the magnitude of that risk is small, and less than that risk seen with many lifestyle factors. HRT is a benefit, not a risk, for those women requiring it.

Effect of statins on estrogen and androgen levels in postmenopausal women treated with estradiol.

OBJECTIVE: A considerable number of postmenopausal women who receive estrogen therapy are also treated for hypercholesterolemia with cholesterol-lowering statins. Statins and steroid hormones can compete for the same steroid-metabolizing enzymes. We investigated whether long-term administration of statins had an effect on serum estrogen and androgen levels in postmenopausal women receiving and not receiving oral estrogen therapy. METHODS: A subgroup analysis from the Estrogen in the Prevention of Atherosclerosis Trial, a randomized, double-blind, placebo-controlled trial, was performed. A total of 222 women were randomized to receive either placebo or 1 mg of oral micronized 17ß-estradiol daily for 2 years. In both the placebo and treatment groups, participants with low density lipoprotein cholesterol levels >160 mg/dl were treated with statins. Blood samples were obtained at baseline and every 6 months during the trial. Serum levels of dehydroepiandrosterone, androstenedione, testosterone, estrone and 17ß-estradiol were measured by radioimmunoassay. RESULTS: Among 86 placebo- and 90 estradiol-treated subjects with baseline and on-trial hormone measurements, no significant differences were observed between the statin-free and statin-treated groups in mean changes from baseline to on-trial levels in any of the androgens or estrogens, whether or not the postmenopausal women were treated with estrogen. CONCLUSION: The results suggest that estrogen therapy and statins can be used simultaneously with no deleterious effects on circulating hormone levels.

Coronary heart disease and hormone replacement therapy after the menopause.

The discordance in coronary heart disease (CHD) outcome between randomized, controlled trials and observational studies of hormone replacement therapy (HRT) is likely the result of the dissimilar cohorts studied. This observation led to the formation of the timing hypothesis that benefits and risks of HRT depend upon age of HRT initiation and/or time of HRT initiation in relation to menopause. This hypothesis has been supported with data from large, randomized, controlled trials that have studied HRT and selective estrogen receptor modulators (SERMs) in the prevention of CHD. Initiation of HRT in women <60 years of age and/or within 10 years of menopause reduces both CHD and total mortality; SERMs have been shown to reduce CHD in women <60 years. What has become clear from the cumulated literature is that in young postmenopausal women who initiate HRT in close proximity to menopause, the adverse effects of HRT are rare and no greater than those of other commonly used pharmacological agents and that the primary prevention benefits for CHD are at least equivalent to those of other commonly used therapies. Additionally, the literature indicates that the duration of HRT confers greater CHD benefit especially in women <60 years who initiate therapy. The cumulated literature dispels misperceptions concerning HRT and CHD.

Postmenopausal oral estrogen therapy affects hemostatic factors, but does not account for reduction in the progression of subclinical atherosclerosis.

BACKGROUND: Hemostatic factors influenced by postmenopausal hormone therapy may contribute to atherosclerosis. The Estrogen in the Prevention of Atherosclerosis Trial (EPAT), a 2-year, randomized, double-blind, placebo-controlled trial, demonstrated reduced subclinical atherosclerosis progression measured by change in common carotid artery intima-media thickness (CIMT) with unopposed oral 17beta-estradiol. OBJECTIVES: To assess the effect of postmenopausal hormone therapy on the levels of several hemostatic factors, and the relationship between these factors and the progression of subclinical atherosclerosis. PATIENTS AND METHODS: We measured tissue plasminogen activator (t-PA) antigen, factor (F) VII, D-dimer and albumin longitudinally, and plasminogen activator inhibitor type 1 (PAI-1) and fibrinogen at trial-end, in 186 postmenopausal women. RESULTS: Estradiol vs. placebo was associated with greater FVII and lower t-PA, albumin, PAI-1 and fibrinogen (all P < or = 0.001), with no estradiol effect on D-dimer (P = 0.42). Only mean on-trial t-PA was positively associated with the absolute level of CIMT on-trial (r = 0.29, P < 0.0001), but this was attenuated with age and body mass index adjustment. No longitudinally measured hemostatic factor was associated with CIMT progression. However, higher CIMT during the trial was significantly related to increases in t-PA. CONCLUSIONS: These results confirm previous findings regarding estrogen's effect on hemostatic factors and show that albumin is negatively associated with estrogen therapy. These hemostatic factors did not account for the reduction of CIMT progression with 17beta-estradiol seen in EPAT. Atherosclerosis itself may affect levels of hemostatic factors (reverse causality), with subsequent involvement in atherosclerosis-associated thrombosis.

Evidence for joint genetic control of insulin sensitivity and systolic blood pressure in hispanic families with a hypertensive proband.

BACKGROUND: The clustering of hypertension, insulin resistance, and obesity remains unexplained. We tested for genetic and nongenetic influences on the association among these traits in Hispanic families with hypertension. METHODS AND RESULTS: Blood pressure and body mass index (BMI) were measured in 331 members of 73 Hispanic families in which an index case (proband) had hypertension. Insulin sensitivity (S(I)) was measured by euglycemic clamp in 287 probands and their spouses (parents' generation) or their adult offspring. Correlation analysis examined relationships among traits within and between generations. Path analysis estimated genetic and nongenetic contributions to variability in systolic blood pressure (SBP), S(I), and the correlation between them. In the offspring, there was a significant correlation between individuals for each trait, as well as significant correlations within and between individuals for all possible pairs of traits. Between generations, SBP, S(I), and BMI in parents correlated with the same traits in their offspring; BMI in parents correlated with S(I) and SBP in offspring; and S(I) in parents correlated with SBP in offspring. Path analysis estimated that among offspring, genetic effects unrelated to BMI accounted for 60.8% of the variation in SBP, 36.8% of the variation in S(I), and 31.5% of the correlation between SBP and S(I) after adjustment for age and sex. Heritable effects related to BMI accounted for an additional 14.0% of variation in SBP, 26.8% of variation in S(I), and 56.3% of variation in their correlation. CONCLUSIONS: Clustering of hypertension and insulin resistance in Hispanic Americans is accounted for in part by heritable factors both associated with and independent of BMI.

In vivo hypertensive arterial wall uptake of radiolabeled liposomes.

Using five sham-operated and seven aortic coarctation-induced hypertensive New Zealand White rabbits intravenously injected with neutral small unilamellar vesicles loaded with [111In]nitrilotriacetic acid, we demonstrated in vivo that the normal aortic arterial wall participates in liposome uptake and that this uptake is increased in the hypertensive aortic wall by approximately threefold (p less than or equal to 0.0001). Among the three regions examined, aortic arch, thoracic aorta, and lower abdominal aorta, the difference in uptake between the normotensive and hypertensive arterial walls was significantly different, p less than or equal to 0.05, p less than or equal to 0.0001, and p less than 0.05, respectively. The uptake by the different regions of the hypertensive arterial wall is consistent with the pathological changes present in these areas. Furthermore, the extent of liposome uptake by the aortic wall is strongly correlated with the height of the blood pressure (r = 0.85, p = 0.001, n = 11). We conclude that neutral small unilamellar liposomes can be used to carry agents into the arterial wall in vivo in the study of hypertensive vascular disease and could be especially useful for the delivery of pharmacologically or biologically active agents that would otherwise be inactivated within the circulation or are impermeable to the arterial wall.

Synergistic inhibition of LDL oxidation by phytoestrogens and ascorbic acid.

Increasing evidence indicates that oxidative modification of low-density lipoprotein (LDL) is an important determinant in atherogenesis, and following menopause, the incidence of coronary heart disease is as prevalent in women as it is in men. Estrogen has been demonstrated to inhibit the susceptibility of LDL to be oxidized, and more recently the use of phytoestrogens has been considered for estrogen replacement therapy. In this study the antioxidant activity of the three major phytoestrogens: genistein, daidzein, and equol were measured in terms of LDL oxidative susceptibility. Increasing levels of genistein, daidzein, and equol inhibited LDL oxidation, and this inhibitory effect was further enhanced in the presence of ascorbic acid. The synergism exhibited by these compounds is of clinical importance to phytoestrogen therapy since the efficacy of phytoestrogens as effective antioxidants is evident at concentration well within the range found in the plasma of subjects consuming soy products. However, this synergism, combined with the low reactivity of the phytoestrogens with peroxyl radicals, suggests that an antioxidant mechanism other then free radical scavenging reactions account for the phytoestrogen antioxidant effect. A structural basis for inhibition of LDL oxidation involving interaction of the phytoestrogens with apoB-100 is postulated.

Influence of lifestyle modification on atherosclerotic progression determined by ultrasonographic change in the common carotid intima-media thickness.

The Monitored Atherosclerosis Regression Study (MARS) was a randomized, double-blind, placebo-controlled angiographic trial of lipid-lowering therapy in subjects with coronary artery disease. Subjects were counseled to follow a low-fat, low-cholesterol diet. At every clinic visit, data were obtained on body weight, dietary intake, alcohol consumption, and tobacco use. Semiannual determinations of early preintrusive atherosclerosis were made with high-resolution B-mode ultrasonography of the carotid artery intima-media thickness (IMT). We evaluated the effects of lifestyle modification (diet, alcohol, smoking, and weight loss) on the rate of carotid artery IMT progression on the 94 subjects randomly assigned to the placebo group. Dietary cholesterol, insoluble fiber, body mass index, and smoking were significant predictors of the annual rate of carotid artery IMT progression (P < 0.05). For subjects experiencing IMT progression, increased intakes of monounsaturated fat relative to saturated fat and stearic acid (18:0) consumption were significant predictors of a reduction in the annual rate of carotid artery IMT progression; for subjects experiencing IMT regression, male sex was a significant predictor of a reduction in the annual rate of carotid artery IMT regression. Modifications reducing body mass index by 5 kg/m2, quitting a 10 cigarette/d smoking habit, and reducing dietary cholesterol intake by 100 mg/d on average would reduce the annual rate of carotid wall IMT progression by 0.13 mm/y, which is equivalent to the maximum rate of IMT progression observed in the MARS placebo group. Progression of early preintrusive atherosclerosis can be reduced and overall regression can occur with dietary and lifestyle modification.

Cholesterol feeding increases plasma and aortic tissue cholesterol oxide levels in parallel: further evidence for the role of cholesterol oxidation in atherosclerosis.

To determine the relationship between plasma and arterial wall oxysterols, plasma and aortic tissue from 7 New Zealand White rabbits fed a high cholesterol (1%) diet for 6 weeks was compared to plasma and aortic tissue from 7 normocholesterolemic rabbits fed standard rabbit chow. Cholesterol and cholesterol oxide fractions were isolated and analyzed by gas chromatography. Normocholesterolemic plasma and aortic tissue contained low levels of cholest-5-ene-3 beta, 7 alpha-diol, cholesta-3,5-dien-7-one, 5,6 alpha-epoxy-5 alpha-cholestan-3 alpha-ol, cholest-5-ene-3 beta, 7 beta-diol, and 5 alpha-cholestane-3 beta, 5,6 beta-triol while hypercholesterolemic plasma and atherosclerotic aorta contained significantly higher levels (P less than 0.05) of these products. Furthermore, 5,6 beta-epoxy-5 alpha-cholestan-3 beta-ol not found in normocholesterolemic plasma or aortic tissue was present in substantial amounts in both hypercholesterolemic plasma and atherosclerotic aortic tissue. Cholest-5-ene-3 beta,25-diol and 3 beta-hydroxycholest-5-ene-7- one not present in normocholesterolemic aorta were present in the atherosclerotic aorta. The oxysterol chromatographic patterns of normocholesterolemic plasma and normocholesterolemic aortic tissue were similar to each other as were the oxysterol chromatographic patterns of hypercholesterolemic plasma and atherosclerotic aortic tissue. The chromatographic patterns between the normocholesterolemic and hypercholesterolemic samples differed however. Possible absorption of the low levels of cholesterol oxides present in the cholesterol feed could account for the elevation of only some of the oxysterols. We conclude that cholesterol oxides exist at some basal level in normocholesterolemia and that these levels are increased by cholesterol-feeding which results in hypercholesterolemia. Our findings demonstrate that there is a strong relationship between plasma and aortic arterial wall levels of cholesterol oxides and suggest that in addition to exogenous sources, formation of cholesterol oxides proceeds via free radical oxidation acting upon elevated cholesterol levels resulting in the accumulation of these potentially cytotoxic and atherogenic products.

Ascorbic acid enhances 17 beta-estradiol-mediated inhibition of oxidized low density lipoprotein formation.

Postmenopausal women who use estrogen appear to be protected from coronary heart disease (CHD). Studies have demonstrated that estrogen can lower low-density lipoprotein (LDL) levels and the antioxidant activity of 17 beta-estradiol can prevent the oxidation of this LDL. Ascorbic acid is regarded as a major hydrophylic antioxidant, however, its impact on the prevention of CHD has yet to be clearly demonstrated. Modified low density lipoprotein (LDL(-)) is an important marker of LDL oxidation in vivo, since it contributes to the oxidative susceptibility of low density lipoprotein, and at physiological levels displays pro-inflammatory and cytotoxic properties. Previously we showed that women taking estrogen replacement therapy have lower LDL(-) levels along with lower predisposition of the LDL to oxidize. In this study, we evaluated the potential action of 17 beta-estradiol (E(2)) in combination with ascorbic acid (AA) measured on the basis of LDL oxidative susceptibility in vitro and in the presence of cultured cells. High concentrations of E(2) were able to inhibit LDL oxidation, whereas in the presence of ascorbic acid nano- to picomolar levels of E(2) were sufficient to suppress LDL oxidation (P<0.05). Preconditioning male aortic endothelial cells (RAEC) with 5 ng/ml of E(2) (E(2)RAEC) reduced the formation of LDL(-) (P<0.005), and a more extensive inhibition was found in the presence of AA (P<0.0001). Interestingly, E(2) enhanced the uptake of LDL in the absence or presence of AA, however, this was not seen for the uptake of LDL(-). These results provide the first evidence that ascorbic acid can enhance the antioxidant effect of E(2) by preventing LDL oxidation by copper ions or cells. The cytoprotective and antiatherogenic effect of E(2) appears to involve a reduction in the extent of oxidized LDL formation and uptake. The enhanced activity of E(2) in the presence of ascorbate indicates that the antioxidant and antiatherosclerosis activity of E(2) may occur at concentrations within the physiological range.

Correlations between measures of atherosclerosis change using carotid ultrasonography and coronary angiography.

Few studies have examined the correlation between change in carotid artery intima-media thickness (IMT) and change in coronary artery disease. In the Cholesterol Lowering Atherosclerosis Study, current nonsmoking men with coronary artery disease were randomized to colestipol-niacin or placebo. Among 133 subjects with baseline and on-trial coronary angiography and carotid ultrasonography, colestipol-niacin treatment significantly reduced progression of atherosclerosis by both end point measures (2-year average change in percent diameter stenosis by coronary angiography and rate of change in carotid IMT). Significant correlations between change in common carotid artery IMT and quantitative coronary angiographic measures of change were evident over all coronary artery lesions, and in mild/moderate (<50% diameter stenosis), but not severe (>/=50% diameter stenosis) coronary artery lesions. In mild/moderate lesions, correlations with change in common carotid IMT were: percent diameter stenosis (r=0.28, P=0.002), minimum lumen diameter (r=-0.28, P=0.002), and vessel edge roughness (r=0.25, P=0.003). While measures obtained by carotid ultrasonography and coronary angiography are correlated, they each assess different aspects of atherosclerosis change.