Contrasting Effects of Oral Versus Transdermal Estrogen on Serum Amyloid A (SAA) and High-Density Lipoprotein–SAA in Postmenopausal Women

High levels of high-density lipoprotein cholesterol may increase the risk of diabetic kidney disease in patients with type 2 diabetes

Studies have indicated that low high-density lipoprotein cholesterol (HDL-C) level is an important risk factor for diabetic kidney disease (DKD) in patients with type 2 diabetes (T2D). However, whether higher HDL-C levels decrease the risk of developing DKD remains unclear. This study aimed to clarify the relationship between HDL-C levels and DKD risk in individuals with T2D in China. In total, 936 patients with T2D were divided into DKD and non-DKD groups. The association between HDL-C levels and DKD risk was evaluated using logistic regression analysis and restricted cubic spline curves adjusted for potential confounders. Threshold effect analysis of HDL-C for DKD risk was also performed. Higher HDL-C levels did not consistently decrease the DKD risk. Furthermore, a nonlinear association with threshold interval effects between HDL-C levels and the incidence of DKD was observed. Patients with HDL-C ≤ 0.94 mmol/L or HDL-C > 1.54 mmol/L had significantly higher DKD risk after adjusting for confounding factors. Interestingly, the association between high HDL-C levels and increased DKD risk was more significant in women. A U-shaped association between HDL-C levels and DKD risk was observed; therefore, low and high HDL-C levels may increase the DKD risk in patients with T2D.

Serum amyloid A and metabolic disease: evidence for a critical role in chronic inflammatory conditions

Serum amyloid A (SAA) subtypes 1-3 are well-described acute phase reactants that are elevated in acute inflammatory conditions such as infection, tissue injury, and trauma, while SAA4 is constitutively expressed. SAA subtypes also have been implicated as playing roles in chronic metabolic diseases including obesity, diabetes, and cardiovascular disease, and possibly in autoimmune diseases such as systemic lupus erythematosis, rheumatoid arthritis, and inflammatory bowel disease. Distinctions between the expression kinetics of SAA in acute inflammatory responses and chronic disease states suggest the potential for differentiating SAA functions. Although circulating SAA levels can rise up to 1,000-fold during an acute inflammatory event, elevations are more modest (∼5-fold) in chronic metabolic conditions. The majority of acute-phase SAA derives from the liver, while in chronic inflammatory conditions SAA also derives from adipose tissue, the intestine, and elsewhere. In this review, roles for SAA subtypes in chronic metabolic disease states are contrasted to current knowledge about acute phase SAA. Investigations show distinct differences between SAA expression and function in human and animal models of metabolic disease, as well as sexual dimorphism of SAA subtype responses.

High HDL (High-Density Lipoprotein) Cholesterol Increases Cardiovascular Risk in Hypertensive Patients

BACKGROUND

Emerging evidence suggests that elevated circulating levels of HDL-C (high-density lipoprotein cholesterol) could be linked to an increased mortality risk. However, to the best of our knowledge, the relationship between HDL-C and specific cardiovascular events has never been investigated in patients with hypertension.

METHODS

To fill this knowledge gap, we analyzed the relationship between HDL-C levels and cardiovascular events in hypertensive patients within the Campania Salute Network in Southern Italy.

RESULTS

We studied 11 987 patients with hypertension, who were followed for 25 534 person-years. Our population was divided in 3 groups according to the HDL-C plasma levels: HDL-C<40 mg/dL (low HDL-C); HDL-C between 40 and 80 mg/dL (medium HDL-C); and HDL-C>80 mg/dL (high HDL-C). At the follow-up analysis, adjusting for potential confounders, we observed a total of 245 cardiovascular events with a significantly increased risk of cardiovascular events in the low HDL-C group and in the high HDL-C arm compared with the medium HDL-C group. The spline analysis revealed a nonlinear U-shaped association between HDL-C levels and cardiovascular outcomes. Interestingly, the increased cardiovascular risk associated with high HDL-C was not confirmed in female patients.

CONCLUSIONS

Our data demonstrate that there is a U-shaped association between HDL-C and the risk of cardiovascular events in male patients with hypertension.

The Effects of Menopause Hormone Therapy on Lipid Profile in Postmenopausal Women: A Systematic Review and Meta-Analysis

Importance: The incidence of dyslipidemia increases after menopause. Menopause hormone therapy (MHT) is recommended for menopause related disease. However, it is benefit for lipid profiles is inconclusive. Objective: To conduct a systematic review and meta-analysis of randomized controlled trials to evaluate the effects of MHT on lipid profile in postmenopausal women. Evidence Review: Related articles were searched on PubMed/Medline, EMBASE, Web of Science, and Cochrane Library databases from inception to December 2020. Data extraction and quality evaluation were performed independently by two reviewers. The methodological quality was assessed using the "Cochrane Risk of Bias checklist". Results: Seventy-three eligible studies were selected. The results showed that MHT significantly decreased the levels of TC (WMD: -0.43, 95% CI: -0.53 to -0.33), LDL-C (WMD: -0.47, 95% CI: -0.55 to -0.40) and LP (a) (WMD: -49.46, 95% CI: -64.27 to -34.64) compared with placebo or no treatment. Oral MHT led to a significantly higher TG compared with transdermal MHT (WMD: 0.12, 95% CI: 0.04-0.21). The benefits of low dose MHT on TG was also concluded when comparing with conventional-dose estrogen (WMD: -0.18, 95% CI: -0.32 to -0.03). The results also showed that conventional MHT significantly decreased LDL-C (WMD: -0.35, 95% CI: -0.50 to -0.19), but increase TG (WMD: 0.42, 95%CI: 0.18-0.65) compared with tibolone. When comparing with the different MHT regimens, estrogen (E) + progesterone (P) regimen significantly increased TC (WMD: 0.15, 95% CI: 0.09 to 0.20), LDL-C (WMD: 0.12, 95% CI: 0.07-0.17) and Lp(a) (WMD: 44.58, 95% CI:28.09-61.06) compared with estrogen alone. Conclusion and Relevance: MHT plays a positive role in lipid profile in postmenopausal women, meanwhile for women with hypertriglyceridemia, low doses or transdermal MHT or tibolone would be a safer choice. Moreover, E + P regimen might blunt the benefit of estrogen on the lipid profile. Clinical Trial Registration: [https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018092924], identifier [No. CRD42018092924].

Controversies Regarding Postmenopausal Hormone Replacement Therapy for Primary Cardiovascular Disease Prevention in Women

The debate over the safety and benefit of hormone replacement therapy (HRT) in postmenopausal women for primary prevention of cardiovascular disease (CVD) has been ongoing for the past several decades. Observational trials in the 1980s suggested a benefit of HRT for primary CVD prevention. However, randomized controlled trials in the 1990s suggested potential harm. Because of these discrepancies, recommendations from authorities on the usage of postmenopausal HRT have fluctuated. Many believed that the timing of HRT initiation relative to the onset of menopause, also known as the "timing hypothesis," was the factor that could explain the differences among these studies. Some recent investigations have concluded that HRT initiated in postmenopausal women near the onset of menopause confers a cardioprotective benefit, while others simply showed that HRT does not cause harm. Research has expanded to evaluate alternative doses, preparations, routes, and formulations, including selective estrogen receptor modulators, to demonstrate their suitability for this purpose. This article is a review of the major research studies of HRT in postmenopausal women with respect to its safety and efficacy for the primary prevention of CVD.

Endogenous estradiol and inflammation biomarkers: potential interacting mechanisms of obesity-related disease

PURPOSE

Disentangling the effects of endogenous estrogens and inflammation on obesity-related diseases requires a clearer understanding of how the two biological mechanisms relate to each other.

METHODS

We studied 155 healthy postmenopausal women not taking menopausal hormone therapy enrolled in the Prostate Lung Colorectal and Ovarian (PLCO) screening cancer trial. From a baseline blood draw, we measured endogenous estradiol and 69 inflammation biomarkers: cytokines, chemokines, adipokines, angiogenic factors, growth factors, acute phase proteins, and soluble receptors. We evaluated the estradiol-inflammation relationship by assessing associations across different models (linear, ordinal logistic, and binary logistic) using a variety of estradiol classifications. We additionally investigated the estradiol-inflammation relationship stratified by baseline obesity status (BMI < 30 stratum and BMI > 30 stratum).

RESULTS

Associations of estradiol with 7 inflammation biomarkers met p < 0.05 statistical significance in linear and ordinal models: C-reactive protein (CRP), adiponectin, chemokine (C-X-C motif) ligand-6, thymus activation-regulated chemokine, eosinophil chemotactic protein, plasminogen activator inhibitor-1, and serum amyloid A. The positive association between estradiol and CRP was robust to model changes. Each standard deviation increase in endogenous estradiol doubled a woman's odds of having CRP levels higher than the study median (odds ratio 2.29; 95% confidence interval 1.28, 4.09). Estradiol was consistently inversely associated with adiponectin. Other estradiol-inflammation biomarker associations were not robust to model changes.

CONCLUSIONS

Endogenous estradiol appears to be associated with CRP and adiponectin; the evidence is limited for other inflammation biomarkers.

The relationship between high-density lipoprotein cholesterol levels and arterial stiffness in a Taiwanese population

BACKGROUND AND AIMS

There are few studies on the association between HDL-C levels and arterial stiffness (AS). HDL-C levels vary in males and females, and it is not clear whether the relationship between HDL-C levels and AS is influenced by gender. The purpose of this study was to investigate gender differences in the association between HDL-C levels and AS in adults.

METHODS AND RESULTS

After excluding subjects using lipid-lowering agent, 7254 subjects were enrolled. The AS was assessed by measuring the brachial-ankle pulse wave velocity (baPWV) value. The quartiles of HDL-C were <38, 38-45, 45-53 and >53 mg/dL in men and <48, 48-57, 57-69 and >68 mg/dL in women, respectively. In subjects aged <50 years, none of the HDL-C quartiles were associated with baPWV values. In subjects aged ≥50 years, the highest quartile of HDL-C (beta: -37.57, 95% CI: -61.61 to -13.54) was negatively related to baPWV values. When considering gender difference in subjects aged ≥50 years, the highest quartile of HDL-C (Q4 beta: -57.22, 95% CI: -95.63 to -18.81) was inversely associated with baPWV values in women, but none of the HDL-C quartiles were related to baPWV values in men.

CONCLUSIONS

A high HDL-C level was associated with a lower risk of AS in subjects aged ≥50 years in women but not in men, although this relationship was not apparent in subjects aged <50 years. The association between HDL-C level and AS is thus influenced by gender in people aged ≥50 years.

Gender-related impact on outcomes of high density lipoprotein in acute ST-elevation myocardial infarction

BACKGROUND AND AIMS

There is rising evidence that cardioprotective functions of high-density lipoprotein (HDL) have significant impact on clinical outcomes. ST-elevation myocardial infarction (STEMI) represents a high-risk vascular condition. Whether higher HDL-cholesterol concentrations in women correspond to protective anti-oxidant properties in the setting of STEMI is unknown.

METHODS

We prospectively assessed gender related differences in the anti-oxidant function of HDL, and the impact of HDL properties on mortality in 242 women and men with STEMI. Blood samples to determine HDL function and sex hormone levels were collected during primary percutaneous coronary intervention.

RESULTS

Patients were stratified according to preserved anti-oxidant HDL function (HDL oxidant index (HOI) < 1) and pro-oxidant HDL (HOI≥1). Despite higher serum levels of HDL-cholesterol in postmenopausal women (48 mg/dl, IQR 42-54, versus 39 mg/dl, IQR33-47, p < 0.001 in men), the proportion of patients with pro-oxidant HDL was not different between women (35%) and men (46%, p = 0.132). Kaplan-Meier analysis revealed higher cardiovascular mortality in both women (p = 0.021) and men (p = 0.045) with pro-oxidant HDL. We identified pro-oxidant HDL as strong and independent predictor of cardiovascular mortality with an adjusted HR of 8.33 (95% CI, 1.55-44.63; p = 0.013) in women and with an adjusted HR of 5.14 (95% CI, 1.61-16.42; p = 0.006) in men. Higher levels of free sex hormones (estradiol and testosterone) were associated with pro-oxidant HDL. HDL-cholesterol levels showed no association with mortality (HR in women 1.03, 95% CI 0.96-1.11, p = 0.45 and HR in men 0.99, 95% CI 0.94-1.05, p = 0.72).

CONCLUSIONS

Total HDL-cholesterol serum levels were not associated with mortality in STEMI patients. Pro-oxidant HDL was a strong and independent predictor of mortality in women and men with STEMI. The present study provides a link between sex hormones, HDL function and clinical events in STEMI patients. In clinical practice and future clinical trials, anti-oxidant properties of HDL rather than total HDL serum levels should be used for risk stratification.

Evaluation of menstrual cycle-related changes in 85 clinical laboratory analytes

OBJECTIVE

The menstrual cycle-related changes in clinical laboratory values were analysed by use of data obtained in the Asian multicentre study aimed at derivation of common reference intervals for 85 major clinical laboratory tests.

METHODS

Among 1876 healthy female volunteers, 893 had regular menstruation. They were classified into five groups according to dates between sample collection and the start of the last menstrual cycle: early follicular phase (1-6 days), late follicular phase (7-12 days), ovulatory phase (13-16 days), early luteal phase (17-22 days), and late luteal phase (23-31 days). Multiple linear regression analysis was performed to evaluate the menstrual cycle-related changes in test results. The magnitude was expressed as a standard deviation ratio of between-phase standard deviation to between-individual standard deviation based on nested ANOVA.

RESULTS

Aside from obvious changes for four sex hormones (oestradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone), we observed statistically significant menstrual cycle-related changes in the following tests (standard deviation ratio >0.15): Na, Cl, creatine kinase, C-reactive protein, serum amyloid A, carbohydrate antigen 125, and parathyroid hormone were higher during the early follicular phase, while insulin, total cholesterol, and white blood cell were higher during the luteal phase. Significant associations of those test items with the four sex hormones were revealed.

CONCLUSIONS

The menstrual cycle-related changes in laboratory test results were revealed in some commonly tested items other than sex hormones. The findings are of interest in understanding female physiology in relation to hormonal changes, but the magnitude of changes is rather small and not very relevant in interpreting test results.

Pharmacokinetics of continuous once-a-week combination 17β-Estradiol/Low- or high-dose levonorgestrel transdermal delivery systems in postmenopausal women

Two open-label, randomized, two-period, crossover studies were performed to determine the safety, delivery rates, and pharmacokinetic properties of a combination estradiol (E2)/levonorgestrel (LNG) transdermal delivery system (TDS). Study 1 enrolled 24 postmenopausal women who received a single TDS containing 4.4 mg E2 and 1.39 mg of LNG (E2/LNG Low) or E2 0.050 mg/24 hours TDS and 0.090 mg LNG oral tablet. Study 2 enrolled 44 postmenopausal women who received either E2/LNG Low or TDS containing 4.4 mg E2 and 2.75 mg LNG (E2/LNG High) weekly for a period of 4 weeks. E2, estrone (E1), LNG, and sex hormone-binding globulin (SHBG) serum concentrations were determined. Overall, both E2/LNG TDS were well tolerated and had excellent adhesion properties. The average daily delivery for E2/LNG Low was 0.045 mg for E2 and 0.0132 mg for LNG. Following weekly delivery of E2/LNG Low or High for 4 weeks, the combination of E2 with two different strengths of LNG did not alter the pharmacokinetic profile of E2. SHBG, total cholesterol, and triglycerides concentrations significantly decreased compared to baseline. Both E2/LNG Low and High TDSs were well tolerated and provided continuous drug delivery over 7 days supporting the benefits of the transdermal route of administration in optimally delivering hormonal therapy.

Serum amyloid A stimulates macrophage foam cell formation via lectin-like oxidized low-density lipoprotein receptor 1 upregulation

Elevated levels of serum amyloid A (SAA) is a risk factor for cardiovascular diseases, however, the role of SAA in the pathophysiology of atherosclerosis remains unclear. Here we show that SAA induced macrophage foam cell formation. SAA-stimulated foam cell formation was mediated by c-jun N-terminal kinase (JNK) signaling. Moreover, both SAA and SAA-conjugated high density lipoprotein stimulated the expression of the important scavenger receptor lectin-like oxidized low-density lipoprotein receptor 1 (LOX1) via nuclear factor-κB (NF-κB). A LOX1 antagonist carrageenan significantly blocked SAA-induced foam cell formation, indicating that SAA promotes foam cell formation via LOX1 expression. Our findings therefore suggest that SAA stimulates foam cell formation via LOX1 induction, and thus likely contributes to atherogenesis.

Serum amyloid A is independently associated with metabolic risk factors but not with early atherosclerosis: the Cardiovascular Risk in Young Finns Study

BACKGROUND

Serum amyloid A (SAA) is a sensitive marker of inflammation and its elevation has been implicated in obesity and in cardiovascular disease, yet data on its regulation in young adults or on its role in early atherosclerosis is scarce. We investigated which factors explain the variation in SAA and analysed whether SAA could be associated with preclinical atherosclerosis.

METHODS

Serum amyloid A levels were measured in participants of the Cardiovascular Risk in Young Finns Study (n = 2280, n = 1254 women, n = 1026 men). Correlates and determinants of SAA were analysed and the effect of SAA on subclinical atherosclerosis, measured as intima-media thickness (IMT) and carotid artery compliance, was evaluated with risk-factor adjusted models.

RESULTS

Serum amyloid A correlated directly and independently of BMI with C-reactive protein (CRP), waist circumference and leptin in both sexes, with total cholesterol, LDL cholesterol and ApolipoproteinA1 (ApoA1) in women and with triglycerides, insulin levels and insulin resistance in men. Use of combined oral contraceptives and intrauterine device was also associated with SAA levels. Determinants for SAA included CRP, leptin and ApoA1 in women, and CRP, leptin and HDL cholesterol in men. SAA levels correlated with carotid compliance in both sexes and with IMT in men, yet SAA had no independent effect on IMT or carotid compliance in multivariable analysis.

CONCLUSIONS

Serum amyloid A was associated with several metabolic risk factors but was not an independent predictor of IMT or carotid artery compliance. Further longitudinal studies will show whether SAA holds a prognostic value as a risk marker, analogously to CRP.

Transdermal hormone therapy in postmenopausal women: a review of metabolic effects and drug delivery technologies

Vasomotor symptoms (VMS) associated with menopause can cause significant discomfort and decrease the quality of life for women in the peri-menopausal and post-menopausal stages of life. Hormone therapy (HT) is the mainstay of treatment for menopausal symptoms and is currently the only therapy proven effective for VMS. Numerous HT options are available to treat VMS, including estrogen-only and estrogen-progestogen combination products to meet the needs of both hysterectomized and nonhysterectomized women. In addition to selecting an appropriate estrogen or estrogen-progestogen combination, consideration should be given to the route of administration to best suit the needs of the patient. Delivery systems for hormone therapy include oral tablets, transdermal patches, transdermal topical (nonpatch) products, and intravaginal preparations. Oral is currently the most commonly utilized route of administration in the United States. However, evidence suggests that oral delivery may lead to some undesirable physiologic effects caused by significant gut and hepatic metabolism. Transdermal drug delivery may mitigate some of these effects by avoiding gut and hepatic first-pass metabolism. Advantages of transdermal delivery include the ability to administer unmetabolized estradiol directly to the blood stream, administration of lower doses compared to oral products, and minimal stimulation of hepatic protein production. Several estradiol transdermal delivery technologies are available, including various types of patches, topical gels, and a transdermal spray.

Serum amyloid A induces CCL2 production via formyl peptide receptor-like 1-mediated signaling in human monocytes

Although the presence of an elevated level of serum amyloid A (SAA) has been regarded as a cardiovascular risk factor, the role of SAA on the progress of atherosclerosis has not been fully elucidated. In the present study, we investigated the effect of SAA on the production of CCL2, an important mediator of monocyte recruitment, and the mechanism underlying the action of SAA in human monocytes. The stimulation of human monocytes with SAA elicited CCL2 production in a concentration-dependent manner. The production of CCL2 by SAA was found to be mediated by the activation of NF-kappaB. Moreover, the signaling events induced by SAA included the activation of ERK and the induction of cyclooxygenase-2, which were required for the production of CCL2. Moreover, SAA-induced CCL2 induction was inhibited by a formyl peptide receptor-like 1 (FPRL1) antagonist. We also found that the stimulation of FPRL1-expressing RBL-2H3 cells induced CCL2 mRNA accumulation, but the vector-expressing RBL-2H3 cells combined with SAA did not. Taken together, our findings suggest that SAA stimulates CCL2 production and, thus, contributes to atherosclerosis. Moreover, FPRL1 was found to be engaged in SAA-induced CCL2 induction, and cyclooxygenase-2 induction was found to be essential for SAA-induced CCL2 expression. These results suggest that SAA and FPRL1 offer a developmental starting point for the treatment of atherosclerosis.

Complex actions of sex steroids in adipose tissue, the cardiovascular system, and brain: Insights from basic science and clinical studies

Recent publications describing the results of the Women's Health Initiative (WHI) and other studies reporting the impact of hormone therapy on aging women have spurred reexamination of the broad use of estrogens and progestins during the postmenopausal years. Here, we review the complex pharmacology of these hormones, the diverse and sometimes opposite effects that result from the use of different estrogenic and progestinic compounds, given via different delivery routes in different concentrations and treatment sequence, and to women of different ages and health status. We examine our new and growing appreciation of the role of estrogens in the immune system and the inflammatory response, and we pose the concept that estrogen's interface with this system may be at the core of some of the effects on multiple physiological systems, such as the adipose/metabolic system, the cardiovascular system, and the central nervous system. We compare and contrast clinical and basic science studies as we focus on the actions of estrogens in these systems because the untoward effects of hormone therapy reported in the WHI were not expected. The broad interpretation and publicity of the results of the WHI have resulted in a general condemnation of all hormone replacement in postmenopausal women. In fact, careful review of the extensive literature suggests that data resulting from the WHI and other recent studies should be interpreted within the narrow context of the study design. We argue that these results should encourage us to perform new studies that take advantage of a dialogue between basic scientists and clinician scientists to ensure appropriate design, incorporation of current knowledge, and proper interpretation of results. Only then will we have a better understanding of what hormonal compounds should be used in which populations of women and at what stages of menopausal/postmenopausal life.

Meta-analysis: effect of hormone-replacement therapy on components of the metabolic syndrome in postmenopausal women

AIM

To quantify the effects of hormone-replacement therapy (HRT) on components of the metabolic syndrome in postmenopausal women.

METHODS

Comprehensive searches of electronic databases were performed from April 1966 to October 2004. We included randomized controlled trials that were of at least 8 weeks duration and evaluated the effect of HRT on metabolic, inflammatory or thrombotic components. Insulin resistance was calculated by homeostasis model assessment (HOMA-IR). Subgroup analysis evaluated the effects for transdermal and oral treatment and for diabetic and non-diabetic women.

RESULTS

Pooled results of 107 trials showed that HRT reduced abdominal fat [-6.8% (CI, -11.8 to -1.9%)], HOMA-IR [-12.9% (CI, -17.1 to -8.6%)] and new-onset diabetes [relative risk 0.7 (CI, 0.6-0.9)] in women without diabetes. In women with diabetes, HRT reduced fasting glucose [-11.5% (CI, -18.0 to -5.1%)] and HOMA-IR [-35.8% (CI, -51.7 to -19.8%)]. HRT also reduced low-density lipoprotein/high-density lipoprotein cholesterol ratio [-15.7% (CI, -18.0 to -13.5%)], lipoprotein(a) [Lp(a)] [-25.0% [CI, -32.9 to -17.1%)], mean blood pressure [-1.7% (CI, -2.9 to -0.5%)], E-selectin [-17.3% (CI, -22.4 to -12.1%)], fibrinogen [-5.5% (CI, -7.8 to -3.2%)] and plasminogen activator inhibitor-1 [-25.1% (CI, -33.6 to -15.5%)]. Oral agents produced larger beneficial effects than transdermal agents, but increased C-reactive protein (CRP) [37.6% (CI, 17.4-61.3%)] and decreased protein S [-8.6% CI, -13.1 to -4.1%)], while transdermal agents had no effect.

CONCLUSIONS

HRT reduces abdominal obesity, insulin resistance, new-onset diabetes, lipids, blood pressure, adhesion molecules and procoagulant factors in women without diabetes and reduced insulin resistance and fasting glucose in women with diabetes. Oral agents adversely affected CRP and protein S, while transdermal agents had no effects.

Responses of inflammatory markers to a low-fat, high-carbohydrate diet: effects of energy intake

BACKGROUND

Inflammation contributes to atherogenesis. Dietary fats may be proinflammatory.

OBJECTIVE

The objective was to determine whether energy intake modulates the effects of low-fat, high-carbohydrate intakes on inflammatory markers.

DESIGN

Twenty-two healthy postmenopausal women with a mean (+/-SD) age of 61 +/- 11 y, who were not receiving hormone replacement therapy, were fed eucaloric diets to reduce their fat intake from 35% to 15% of energy. Next, the women consumed a 15%-fat ad libitum diet under free-living conditions. Serum highly sensitive C-reactive protein, interleukin 6, HDL serum amyloid A, and adiponectin concentrations were measured at the end of the eucaloric and ad libitum low-fat, high-carbohydrate intakes.

RESULTS

The eucaloric diet decreased adiponectin from 16.3 +/- 2.1 to 14.2 +/- 2.0 mg/L (P < 0.05) and increased triacylglycerol from 131 +/- 11 to 164 +/- 14 mg/dL (P < 0.01). The ad libitum low-fat diet caused 6 kg weight loss and decreased highly sensitive C-reactive protein from 4.3 +/- 0.6 to 2.5 +/- 0.5 mg/L (P < 0.01), decreased HDL serum amyloid A from 10.3 +/- 1.8 to 5.7 +/- 1.3 mg/L (P < 0.001), increased adiponectin from 14.2 +/- 2.0 to 16.3 +/- 1.7 mg/L (P < 0.05), and decreased triacylglycerol from 164 +/- 14 to 137 +/- 15 mg/dL (P < 0.05).

CONCLUSION

During the eucaloric phase, the low-fat, high-carbohydrate diet exerted unfavorable effects on the inflammatory markers. In contrast, the ad libitum low-fat, high-carbohydrate intake caused weight loss and affected inflammatory markers favorably. Thus, the energy content of a low-fat, high-carbohydrate diet determines changes in inflammatory markers.

Temporal gene induction patterns in sheepshead minnows exposed to 17β-estradiol

Gene arrays provide a powerful method to examine changes in gene expression in fish due to chemical exposures in the environment. In this study, we expanded an existing gene array for sheepshead minnows (Cyprinodon variegatus) (SHM) and used it to examine temporal changes in gene expression for male SHM exposed to 100 ng 17beta-estradiol (E(2))/L for five time points between 0 and 48 hr. We found that in addition to the induction of genes involved in oocyte development (vitellogenin [VTG], zona radiata [ZRP]), other genes involved in metabolism and the inflammatory response are also affected. We identified five patterns of temporal induction in genes whose expression was modified due to E(2) exposure. We validated the gene array data for the expression of VTG 1, VTG 2, ZRP 2 and ZRP 3 and found that with low levels of exogenous E(2) (100 ng E(2)/L) exposure, ZRP expression precedes VTG expression. However, at higher concentrations of E(2) (500 ng E(2)/L), the difference in temporal expression appears to be lost. Exposure to high levels of environmental contaminants may affect the normal ordered expression of genes required for reproduction. Gene expression profiling using arrays promises to be a valuable tool in the field of environmental toxicology. As more genes are identified for species used in toxicological testing, researchers will be better able to predict adverse effects to chemical exposures and to understand the relationships between changes in gene expression and changes in phenotype.

Effects of Transdermal Estrogen Replacement Therapy on Cardiovascular Risk Factors

The prevalence of hypertension and cardiovascular disease increases dramatically after menopause in women, implicating estrogen as having a protective role in the cardiovascular system. However, recent large clinical trials have failed to show cardiovascular benefit, and have even demonstrated possible harmful effects, of opposed and unopposed estrogen in postmenopausal women. While these findings have led to a revision of guidelines such that they discourage the use of estrogen for primary or secondary prevention of heart disease in postmenopausal women, many investigators have attributed the negative results in clinical trials to several flaws in study design, including the older age of study participants and the initiation of estrogen late after menopause.Because almost all clinical trials use oral estrogen as the primary form of hormone supplementation, another question that has arisen is the importance of the route of estrogen administration with regards to the cardiovascular outcomes. During oral estrogen administration, the concentration of estradiol in the liver sinusoids is four to five times higher than that in the systemic circulation. This supraphysiologic concentration of estrogen in the liver can modulate the expression of many hepatic-derived proteins, which are not observed in premenopausal women. In contrast, transdermal estrogen delivers the hormone directly into the systemic circulation and, thus, avoids the first-pass hepatic effect.Although oral estrogen exerts a more favorable influence than transdermal estrogen on traditional cardiovascular risk factors such as high- and low-density lipoprotein-cholesterol levels, recent studies have indicated that oral estrogen adversely influences many emerging risk factors in ways that are not seen with transdermal estrogen. Oral estrogen significantly increases levels of acute-phase proteins such as C-reactive protein and serum amyloid A; procoagulant factors such as prothrombin fragments 1+2; and several key enzymes involved in plaque disruption, while transdermal estrogen does not have these adverse effects.Whether the advantages of transdermal estrogen with regards to these risk factors will translate into improved clinical outcomes remains to be determined. Two ongoing clinical trials, KEEPS (Kronos Early Estrogen Prevention Study) and ELITE (Early versus Late Intervention Trial with Estradiol) are likely to provide invaluable information regarding the role of oral versus transdermal estrogen in younger postmenopausal women.

Reverse cholesterol transport and cholesterol efflux in atherosclerosis

Reverse cholesterol transport (RCT) is a pathway by which accumulated cholesterol is transported from the vessel wall to the liver for excretion, thus preventing atherosclerosis. Major constituents of RCT include acceptors such as high-density lipoprotein (HDL) and apolipoprotein A-I (apoA-I), and enzymes such as lecithin:cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), hepatic lipase (HL) and cholesterol ester transfer protein (CETP). A critical part of RCT is cholesterol efflux, in which accumulated cholesterol is removed from macrophages in the subintima of the vessel wall by ATP-binding membrane cassette transporter A1 (ABCA1) or by other mechanisms, including passive diffusion, scavenger receptor B1 (SR-B1), caveolins and sterol 27-hydroxylase, and collected by HDL and apoA-I. Esterified cholesterol in the HDL is then delivered to the liver for excretion. In patients with mutated ABCA1 genes, RCT and cholesterol efflux are impaired and atherosclerosis is increased. In studies with transgenic mice, disruption of ABCA1 genes can induce atherosclerosis. Levels of HDL are inversely correlated with incidences of cardiovascular disease. Supplementation with HDL or apoA-I can reverse atherosclerosis by accelerating RCT and cholesterol efflux. On the other hand, pro-inflammatory factors such as interferon-gamma (IFN-gamma), endotoxin, tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta), can be atherogenic by impairing RCT and cholesterol efflux, according to in vitro studies. RCT and cholesterol efflux play a major role in anti-atherogenesis, and modification of these processes may provide new therapeutic approaches to cardiovascular disease. Further research on new modifying factors for RCT and cholesterol efflux is warranted.

Clinical Pharmacology and Differential Cognitive Efficacy of Estrogen Preparations

Menopause is associated with a significant decline in levels of estrogen, which reportedly leads to several distressing symptoms and adverse health effects on various target tissues including those on bones, heart, and brain. Although effective, the long-term safety and feasibility of therapy with both unopposed and opposed oral conjugated equine estrogen has been questioned by the recent findings of both the Women's Health Initiative (WHI) and the Women's Health Initiative Memory Study (WHIMS). The findings of both these studies have raised several critical issues related to hormone therapy that need to be systematically evaluated in clinical studies. Specifically, these issues relate to the differential efficacy and adverse-effects profile of various forms of estrogen and progestins, the importance of the route of administration of estrogen, the best timing to initiate postmenopausal hormone therapy, and the efficacy of cyclic versus continuous hormone therapy. This article focuses on estrogen and discusses issues related to selecting the best form and route of administration of the hormone. It includes information on basic clinical pharmacology of various forms of estrogen, neuroendocrinology of the menopause, neurobiology of estradiol and estrone, and results of selected basic science and human intervention studies with relevance to identifying the best form and route of administration of estrogen.

Diet-induced weight loss is associated with decreases in plasma serum amyloid a and C-reactive protein independent of dietary macronutrient composition in obese subjects

Elevated levels of serum amyloid A (SAA) and C-reactive protein (CRP) have been associated with increased cardiovascular risk. Although levels of CRP decrease with weight loss, it is not known whether SAA decreases with weight loss or whether dietary macronutrient composition affects levels of either SAA or CRP. SAA and CRP levels were measured retrospectively on baseline and 3-month plasma samples from 41 obese (mean body mass index 33.63 +/- 1.86 kg/m2) women completing a randomized trial comparing a low-fat diet (n = 19) and a very low-carbohydrate diet (n = 22). For the 41 participants, there were significant decreases from baseline to 3 months in both LogSAA (P = 0.049) and LogCRP (P = 0.035). The very low-carbohydrate dieters had a significantly greater decrease in LogSAA (P = 0.04), but their weight loss also was significantly greater (-7.6 +/- 3.2 vs. -4.3 +/- 3.5 kg, P < 0.01). In this study, the decreases in inflammatory markers correlated significantly with weight loss (r = 0.44, P = 0.004 vs. LogSAA and r = 0.35, P = 0.03 vs. LogCRP). Also, change in LogSAA correlated with change in insulin resistance (r = 0.35, P = 0.03). Thus, in otherwise healthy, obese women, weight loss was associated with significant decreases in both SAA and CRP. These effects were proportional to the amount of weight lost but independent of dietary macronutrient composition.