Association of Aromatase Inhibitors With Coronary Heart Disease in Women With Early Breast Cancer

Risk of Cardiovascular Events and Lipid Profile Change in Patients with Breast Cancer Taking Aromatase Inhibitor: A Systematic Review and Meta-Analysis

Cardiovascular disease (CVD) is one of the most common comorbidities in breast cancer survivors. Recently, the target population and treatment period for aromatase inhibitor (AI) treatment in breast cancer patients has been expanding. However, information on adverse CVD events from the long-term use of AI is still lacking. The aim of this study was to investigate the CVD side effects of AI treatment and to evaluate the changes in lipid profile during AI treatment. A systematic search of PubMed (Medline), EMBASE, and Cochrane Library databases reporting on cardiovascular outcomes or lipid profiles change in adult female breast cancer patients (>19 years old) with AI was performed. The pooled analysis of 25 studies showed that the prevalence rate of any type of cardiovascular disease was 6.08 per 100 persons (95% CI 2.91-10.31). Angina was the most common type of heart-related cardiovascular event accounting for 3.85 per 100 persons, followed by any type of stroke (3.34) and venous thromboembolism (2.95). Ischemic stroke (OR 1.39, 95% CI 1.07-1.81) and myocardial infarction (OR 1.30, 95% CI 0.88-1.93) were more common in AI compared with tamoxifen, whereas the prevalence of venous thromboembolism (OR 0.61, 95% CI 0.37-1) was significantly lower in the AI group. In addition, treatment with AI for 6-12 months showed a decrease in HDL-cholesterol and an increase in LDL-cholesterol and total cholesterol. Various CVDs can occur when using AI, and in particular, the risk of MI and ischemic stroke increases in comparison with the adverse effect of tamoxifen. The occurrence of CVD might be related to the deterioration of the lipid profile after AI treatment. Therefore, a customized individualization strategy considering each patient's CV risk factors is needed during AI treatment.

Aromatase inhibition increases blood pressure and markers of renal injury in female rats

Aromatase is a monooxygenase that catalyzes the rate-limiting step of estrogen biosynthesis from androgens. Aromatase inhibitors are widely used for the treatment of patients with hormone receptor-positive breast cancer. However, the effects of aromatase inhibitors on cardiovascular and renal health in females are understudied. Given that estrogen is protective against cardiovascular and kidney diseases, we hypothesized that aromatase inhibition elevates blood pressure and induces kidney injury in female Sprague-Dawley rats. Twelve-week-old female rats were implanted with radiotelemetry transmitters to continuously monitor blood pressure. After baseline blood pressure recording, rats were randomly assigned to treatment with the aromatase inhibitor anastrozole (ASZ) or vehicle (Veh) in drinking water. Twenty days after treatment initiation, rats were shifted from a normal-salt (NS) diet to a high-salt (HS) diet for an additional 40 days. Rats were euthanized 60 days after treatment initiation. Body weight increased in both groups over the study period, but the increase was greater in the ASZ-treated group than in the Veh-treated group. Mean arterial pressure increased in ASZ-treated rats during the NS and HS diet phases but remained unchanged in Veh-treated rats. In addition, urinary excretion of albumin and kidney injury marker-1 and plasma urea were increased in response to aromatase inhibition. Furthermore, histological assessment revealed that ASZ treatment increased morphological evidence of renal tubular injury and proximal tubular brush border loss. In conclusion, chronic aromatase inhibition in vivo with ASZ increases blood pressure and markers of renal proximal tubular injury in female Sprague-Dawley rats, suggesting an important role for aromatization in the maintenance cardiovascular and renal health in females.NEW & NOTEWORTHY Aromatase enzyme catalyzes the rate-limiting step in estrogen biosynthesis. Aromatase inhibitors are clinically used for the treatment of patients with breast cancer; however, the impact of inhibiting aromatization on blood pressure and renal function is incompletely understood. The present findings demonstrate that systemic anastrozole treatment increases blood pressure and renal tubular injury markers in female rats fed a high-salt diet, suggesting an important role for aromatization in preserving cardiovascular and renal health in females.

Risk of cardiovascular disease in breast cancer patients receiving aromatase inhibitors vs. tamoxifen: A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Breast cancer is one of the leading causes of morbidity and mortality in women worldwide. In order to reduce the risks of its recurrence, endocrine therapies, such as tamoxifen and aromatase inhibitors are commonly administered. Despite having a similar efficacy in preventing breast cancer recurrence, these drugs differ in terms of instigating cardiovascular morbidities. Recent randomized controlled trials and cohort studies provide inconclusive evidence of the cardiovascular risks associated with the administration of these endocrine therapies. This present review and meta-analysis evaluates the comparative cardiovascular adverse event outcomes in breast cancer patients receiving tamoxifen and aromatase inhibitors. To evaluate the comparative cardiovascular adverse outcomes, such as venous thromboembolism, heart failure, angina, myocardial infarction and stroke in patients with breast cancer receiving tamoxifen and aromatase inhibitors.

METHODS

A systematic search of the academic literature was performed according to the PRISMA guidelines across five databases, including Web of Science, EMBASE, CENTRAL, Scopus, and MEDLINE. A random-effect meta-analysis was conducted to compare the cardiovascular adverse events (i.e. venous thromboembolism, heart failure, angina, myocardial infarction, stroke) in breast cancer patients treated with tamoxifen and aromatase inhibitors.

RESULTS AND DISCUSSION

From 993 studies, 20 eligible studies were identified, with 174,142 female breast cancer patients (mean age: 67.4 ± 3.8 years). A meta-analysis revealed insignificantly (p > 0.05) higher risks of venous thromboembolism (Odds ratio, 95% CI: 1.70, 0.91-3.18) in patients treated with tamoxifen as compared to aromatase inhibitors. We also observed insignificantly higher risks of stroke (0.93, 0.45-1.91), angina (0.77, 0.12-4.59), myocardial infarction (0.74, 0.30-1.79), and heart failure (0.81, 0.22-2.91) in patients receiving aromatase inhibitors as compared to tamoxifen.

WHAT IS NEW AND CONCLUSIONS

The study provides evidence regarding the comparative cardiovascular adverse outcomes between breast cancer patients consuming tamoxifen and aromatase inhibitors. The study reports an insignificant increase in the events of stroke, angina, myocardial infarction, and heart failure in breast cancer patients treated with aromatase inhibitors as compared to tamoxifen. The study also reports that tamoxifen treatment is associated with an insignificant increase in the events of venous thromboembolism as compared to treatment with aromatase inhibitors.

Association Between Aromatase Inhibitors and Myocardial Infarction Morbidity in Women With Breast Cancer: A Meta-Analysis of Observational Studies

BACKGROUND

The cardiovascular toxicity of aromatase inhibitors (AIs) for women with estrogen receptor-positive breast cancer is controversial. We aimed to evaluate the association between AIs and the risk of myocardial infarction (MI) in women with estrogen receptor-positive breast cancer based on real-world studies.

METHOD

PubMed, Embase, and Cochrane Library were searched to identify studies that estimated the association between MI risk and AIs. A random-effects model was used to evaluate the hazard ratio (HR) and 95% confidence intervals (CIs) of the predefined outcomes.

RESULTS

A total of 134 476 patients from eight cohort studies were enrolled in our analysis. For MI incidence, no significant difference was found between the users of AIs and non-users (HR: .98, 95% CI: .83-1.17). The subgroup analysis of patients without a history of cardiovascular disease (CVD) suggested a reduced risk of MI (HR: .86, 95% CI: .77-.96). No significant difference was found for ischemic stroke (HR: .93, 95% CI: .82-1.07) and heart failure (HR: 1.24, 95% CI: .92-1.66) between the two groups.

CONCLUSION

Based on real-world data, AIs may be a safe treatment route for patients with estrogen receptor-positive breast cancer and those with a history of CVD. AIs caused a major decrease in MI in patients without CVD history. However, more in-depth investigations are needed to explore the association between AI use and the incidence of MI in the treatment of estrogen receptor-positive breast cancer.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

Care for Breast Cancer Survivors

The number of cancer survivors is increasing globally. More than 15.5 million Americans in 2016 and 1.3 million Koreans in 2013 were living with cancer history. This growing population is expected to increase due to marked development of cancer treatment and early detection. Especially, breast cancer is the second most common cancer in Korean women with relatively favorable 5-year survival rate. Cancer survivors generally face various physical, psychological, and social problems including late-effect or long-term effect after cancer treatment and high risk for second primary cancer and comorbid chronic diseases such as cardiovascular disease and bone health. Breast cancer survivors also encounter wide range of health problems. To satisfy their complex needs, comprehensive supports are required. We categorized the strategy of comprehensive care for breast cancer survivors into (1) Surveillance for primary cancer, (2) Screening of second primary cancer, (3) Management of comorbid health condition, (4) Promoting healthy lifestyle behaviors, and (5) Preventive care. In the future, studies for providing best comprehensive care for breast cancer survivors are needed according to the individuals' demand.

Aromatase inhibitor use is a risk factor of carotid plaque presence in endocrine-responsive breast cancer patients

BACKGROUND/AIMS

The aromatase inhibitors (AIs) are well known anti-hormonal therapy in endocrine-responsive breast cancer patients. It can lead to dyslipidemia and be the risk factor of cardiovascular disease due to low estrogen level. However, some recent studies comparing AIs with placebo have shown controversial results. The aim of this study was to investigate lipid profiles, measurement of carotid intima-media thickness (IMT) and the presence of plaque among endocrine-responsive breast cancer treated with AIs compared to ones that were not treated with AIs.

METHODS

A total of 85 postmenopausal women, who underwent breast cancer surgery during the age of 50 to 64 without history of statin use were included. There were 42 patients who were treated with AIs over 1 year (group 1) and 43 patients without AIs use (group 2). Serum total cholesterol, high density lipoprotein cholesterol, triglycerides, fasting blood glucose, carotid IMT, and presence of plaque were assessed.

RESULTS

The baseline characteristics were similar between two groups and there was no significant difference in carotid IMT irrespective of AIs administration. However, ultrasonographic evaluation of carotid artery revealed that the presence of plaque in AI users was significantly higher than in non-AI users (66.7% vs. 41.9%, p = 0.02; odds ratio, 4.21 in adjusted model; p = 0.01). History of diabetes was also the significant risk factor for the plaque formation.

CONCLUSION

There was no significant difference in lipid profile itself between two groups, but more importantly the presence of the plaque was much higher indicating possible detrimental effect of AI on cardiovascular system.

Estrogen-mediated protection against coronary heart disease: The role of the Notch pathway

Estrogen regulates a plethora of biological processes, under physiological and pathological conditions, by affecting key pathways involved in the regulation of cell proliferation, fate, survival and metabolism. The Notch receptors are mediators of communication between adjacent cells and are key determinants of cell fate during development and in postnatal life. Crosstalk between estrogen and the Notch pathway intervenes in many processes underlying the development and maintenance of the cardiovascular system. The identification of molecular mechanisms underlying the interaction between these types of endocrine and juxtacrine signaling are leading to a deeper understanding of physiological conditions regulated by these steroid hormones and, potentially, to novel therapeutic approaches to prevent pathologies linked to reduced levels of estrogen, such as coronary heart disease, and cardiotoxicity caused by hormone therapy for estrogen-receptor-positive breast cancer.

Alteration at transcriptional level of cardiac renin-angiotensin system by letrozole treatment

INTRODUCTION

The use of aromatase inhibitors (AIs) for breast cancer led to a marked change in ventricular function. Since accumulating evidence indicates that overactivation of the cardiac renin-angiotensin system (RAS) plays an important role in the development of cardiovascular diseases such as hypertrophy and remodelling, we aimed to investigate whether letrozole alters the transcription level of RAS related genes in the cardiac tissue.

METHODS

Twenty four rats were randomly divided into four groups (n = 6 per group): two groups were letrozole treated (1 and 2 mg/kg/day orally), one group was vehicle treated (DMSO) and one group was the control group without any treatment. 12 weeks after beginning treatment with letrozole, we examined the rate of transcription of renin, angiotensinogen, AngII type 1a and 1b (AT1a and AT1b) and type 2 receptors (AT2) in the rat heart using real-time polymerase chain reaction.

RESULTS

The cardiac mRNA levels of several components of the RAS in the rats treated with letrozole were significantly increased including AT1a receptor (80%), renin (51%), and angiotensinogen (33%). Though not significant, AT2 receptor levels were observed to decrease with increasing doses of letrozole.

CONCLUSIONS

Letrozole can induce significant changes in some RAS related genes. These alterations are important to understand the pathways and consequences beyond cardiac events induced by breast cancer treatments.

Beyond cardiomyocyte loss: Role of Notch in cardiac aging

The knowledge of the cellular events occurring in the aging heart has dramatically expanded in the last decade and is expected to further grow in years to come. It is now clear that impaired function and loss of cardiomyocytes are major features of cardiac aging, but other events are likewise important. In particular, accumulating experimental evidence highlights the importance of fibroblast and cardiac progenitor cell (CPC) dysfunction. The Notch pathway regulates cardiomyocyte, fibroblast, and CPC activity and, thus, may be critically involved in heart disease associated with advanced age, especially heart failure. In a translational perspective, thorough investigation of the Notch system in the aging myocardium may lead to the identification of molecular targets for novel therapies for age-related cardiac disease.

The protective role of estrogen and estrogen receptors in cardiovascular disease and the controversial use of estrogen therapy

Epidemiologic studies have previously suggested that premenopausal females have reduced incidence of cardiovascular disease (CVD) when compared to age-matched males, and the incidence and severity of CVD increases postmenopause. The lower incidence of cardiovascular disease in women during reproductive age is attributed at least in part to estrogen (E2). E2 binds to the traditional E2 receptors (ERs), estrogen receptor alpha (ERα), and estrogen receptor beta (ERβ), as well as the more recently identified G-protein-coupled ER (GPR30), and can exert both genomic and non-genomic actions. This review summarizes the protective role of E2 and its receptors in the cardiovascular system and discusses its underlying mechanisms with an emphasis on oxidative stress, fibrosis, angiogenesis, and vascular function. This review also presents the sexual dimorphic role of ERs in modulating E2 action in cardiovascular disease. The controversies surrounding the clinical use of exogenous E2 as a therapeutic agent for cardiovascular disease in women due to the possible risks of thrombotic events, cancers, and arrhythmia are also discussed. Endogenous local E2 biosynthesis from the conversion of testosterone to E2 via aromatase enzyme offers a novel therapeutic paradigm. Targeting specific ERs in the cardiovascular system may result in novel and possibly safer therapeutic options for cardiovascular protection.

Relationship between physical activity practice and metabolic profile of postmenopausal women under treatment with aromatase inhibitors for breast cancer

OBJECTIVE

To analyze the relationship between physical activity practice and metabolic profile of postmenopausal women under treatment with aromatase inhibitors (AIs) for the treatment of breast cancer.

STUDY DESIGN

Cross-sectional study, conducted with 101 postmenopausal women (aged 50-80 years). The sample was divided into two groups; group without cancer (GW; n=65) and breast cancer group treated with AIs (GC; n=36). Physical activity (PA) was evaluated by questionnaire. Correlations between physical activity and metabolic variables were made by Pearson's correlation coefficient and the magnitude of these relationships by linear regression.

RESULTS

In GW, there were observed significant inverse correlations between physical activity and VLDL cholesterol (β=-0.036; 95% CI=-0.068; -0.004); triglycerides (β=-0.036; 95% CI=-0.015; -0.002); glycose (β=-0.029; 95% CI=-0.047; -0.012); and C-reactive protein (β=-0.44; 95% CI=-0.085; -0.003). However, for women under treatment of AIs there was no relationship between physical activity and metabolic variables.

CONCLUSION

The amount of physical activity practice is inversely related to lipid profile, glucose and C-reactive protein in women without breast cancer. This relation was not observed in the cancer survivors, suggesting that the use of aromatase inhibitors could influence or low intensity of physical activity.

Aromatase: Contributions to Physiology and Disease in Women and Men

Aromatase (estrogen synthetase; EC 1.14.14.1) catalyzes the demethylation of androgens' carbon 19, producing phenolic 18-carbon estrogens. Aromatase is most widely known for its roles in reproduction and reproductive system diseases, and as a target for inhibitor therapy in estrogen-sensitive diseases including cancer, endometriosis, and leiomyoma (141, 143). However, all tissues contain estrogen receptor-expressing cells, the majority of genes have a complete or partial estrogen response element that regulates their expression (61), and there are plentiful nonreceptor effects of estrogens (79); therefore, the effect of aromatase through the provision of estrogen is almost universal in terms of health and disease. This review will provide a brief but comprehensive overview of the enzyme, its role in steroidogenesis, the problems that arise with its functional mutations and mishaps, the roles in human physiology of aromatase and its product estrogens, its current clinical roles, and the effects of aromatase inhibitors. While much of the story is that of the consequences of the formation of its product estrogens, we also will address alternative enzymatic roles of aromatase as a demethylase or nonenzymatic actions of this versatile molecule. Although this short review is meant to be thorough, it is by no means exhaustive; rather, it is meant to reflect the cutting-edge, exciting properties and possibilities of this ancient enzyme and its products.

Identification of a CYP19 Gene Single-Nucleotide Polymorphism Associated with a Reduced Risk of Coronary Heart Disease

OBJECTIVE

An imbalance in sex hormone ratios has been identified in coronary heart disease (CHD), and as a key enzyme in the conversion of androgen to estrogen, aromatase plays an important role in the balance of sex hormone levels. However, there is a paucity of research into the potential roles of aromatase in CHD. In this study, we investigated associations between single-nucleotide polymorphisms (SNPs) in the CYP19 gene, which encodes aromatase, and CHD.

METHODS

We collected 1706 blood samples from CHD patients and control participants and used propensity score matching techniques to match case and control groups with respect to confounding factors. In a final study population, including 596 individuals, we conducted a case-control study to identify associations between three SNPs in CYP19 and CHD using χ(2) or Fisher exact tests, and binary logistic regression analysis. Differences in lipid levels and parameters of echocardiography among individuals with different genotypes were assessed by one-way analysis of variance.

RESULTS

The distributions of rs2289105 alleles in the CYP19 gene differed significantly between the CHD and control groups (p = 0.014), and the heterozygote CT genotype was associated with a significantly lower risk of CHD compared to the homozygous wild-type CC genotype (p = 0.0063 and odds ratio = 0.575). However, blood lipid levels and echocardiographic parameters among individuals with different genotypes did not differ between the CHD and control groups.

CONCLUSIONS

The CT genotype of the rs2289105 polymorphism in the CYP19 gene is associated with a decreased risk of CHD and may be a genetic marker of protection from CHD.