Transdermal Versus Oral Estrogen Therapy in Postmenopausal Smokers: Hemodynamic and Endothelial Effects

Effects of Estrogen on Cardiac mRNA and LncRNA Expression Profiles in Hypertensive Mice

Estrogen is a vascular protection factor and plays a protective role in the pathogenesis of gender differences in cardiovascular diseases. This study was to address the possible mechanisms that may explain the relationship between estradiol configuration-17β-estradiol (E2) and ventricular remodeling. Here, we show that a total of 1499 LncRNAs and 680 mRNAs significantly differently expressed were identified. This result indicates that estradiol has a global role in regulating heart gene expression profiles in female mice. Go and Pathway functional cluster analysis showed that the antagonism of E2 on cardiac remodeling and AngII-induced pathological changes in female mice may be related to physiological processes such as circadian rhythm disorder and ion channel dysfunction. Graphical Abstract.

The Effect of Perimenopausal Transdermal Estradiol and Micronized Progesterone on Markers of Risk for Arterial Disease

BACKGROUND

The arterial effects of hormone therapy remain controversial. This study tested the effects of transdermal estradiol plus intermittent micronized progesterone (TE + IMP) in healthy perimenopausal and early postmenopausal women on several mechanisms involved in the pathophysiology of arterial disease.

METHODS

Healthy perimenopausal and early postmenopausal women, ages 45 to 60 years, were enrolled in this randomized, double-blind, placebo-controlled trial. Women were randomized to receive TE (0.1 mg/day) + IMP (200 mg/day for 12 days) or identical placebo patches and pills for 12 months. Outcomes included: change in stress reactivity composite z-score (combining inflammatory, cortisol, and hemodynamic responses to a standardized psychological laboratory stressor); flow-mediated dilation (FMD) of the brachial artery (an index of vascular endothelial function); baroreflex sensitivity; and metabolic risk (presence of the metabolic syndrome or insulin resistance), all assessed at baseline and at months 6 and 12.

RESULTS

Of 172 women enrolled, those assigned to TE + IMP tended to have higher resting baroreflex sensitivity than those assigned to placebo across the 6- and 12-month visits. Although treatment groups did not differ in terms of the other prespecified outcomes, a significant treatment-by-age interaction was found for FMD and stress reactivity such that an age-related decrease in FMD and increase in stress reactivity were seen among women assigned to placebo but not those assigned to TE + IMP. Women on TE + IMP also had lower resting diastolic blood pressure, lower levels of low-density lipoprotein cholesterol, and higher baroreflex sensitivity during stress testing.

CONCLUSIONS

TE + IMP tended to improve cardiac autonomic control and prevented age-related changes in stress reactivity and endothelial function among healthy perimenopausal and early postmenopausal women.

Ovarian hormone fluctuation, neurosteroids, and HPA axis dysregulation in perimenopausal depression: a novel heuristic model

OBJECTIVE

In this conceptual review, the authors propose a novel mechanistic candidate in the etiology of depression with onset in the menopause transition ("perimenopausal depression") involving alterations in stress-responsive pathways, induced by ovarian hormone fluctuation.

METHOD

The relevant literature in perimenopausal depression, including prevalence, predictors, and treatment with estrogen therapy, was reviewed. Subsequently, the growing evidence from animal models and clinical research in other reproductive mood disorders was synthesized to describe a heuristic model of perimenopausal depression development.

RESULTS

The rate of major depressive disorder and clinically meaningful elevations in depressive symptoms increases two- to threefold during the menopause transition. While the mechanisms by which ovarian hormone fluctuation might impact mood are poorly understood, growing evidence from basic and clinical research suggests that fluctuations in ovarian hormones and derived neurosteroids result in alterations in regulation of the HPA axis by γ-aminobutyric acid (GABA). The authors' heuristic model suggests that for some women, failure of the GABAA receptor to regulate overall GABA-ergic tone in the face of shifting levels of these neurosteroids may induce HPA axis dysfunction, thereby increasing sensitivity to stress and generating greater vulnerability to depression.

CONCLUSIONS

The proposed model provides a basis for understanding the mechanisms by which the changing hormonal environment of the menopause transition may interact with the psychosocial environment of midlife to contribute to perimenopausal depression risk. Future research investigating this model may inform the development of novel pharmacological treatments for perimenopausal depression and related disorders, such as postpartum depression and premenstrual dysphoric disorder.

Hormone replacement therapy in the treatment of perimenopausal depression

The menopause transition is associated with a two to fourfold increased risk in major depressive disorder (MDD) and clinical elevations in depressive symptoms. While the pathophysiological mechanisms underlying this increased risk remain uncertain, ovarian hormone fluctuation is believed to play a role. To the extent that this is the case, hormone replacement therapy (HRT), through its hormone-stabilizing effects, represents a viable antidepressant treatment. The current review summarizes the most recent literature evaluating the efficacy of HRT in treating MDD in peri- and postmenopausal women. In addition, to provide a clinical context in which to interpret this research, the endocrinology and clinical phenomenology related to depression with onset in the menopause transition (D-MT) are discussed. The available evidence suggests that HRT, specifically involving estrogen delivered through a skin patch, is a promising intervention in the treatment of D-MT. However, HRT of any form is an ineffective antidepressant in women who are well into the postmenopausal period.

Mechanisms underlying hemodynamic and neuroendocrine stress reactivity at different phases of the menstrual cycle

This study examined the association of menstrual cycle phase with stress reactivity as well as the hormonal and neuroendocrine mechanisms contributing to cycle effects. Fifty-seven women underwent a modified Trier Social Stress Test during the early follicular, late follicular, and luteal phases of the menstrual cycle. Greater increases in cardiac index (CI) and greater decreases in vascular resistance index (VRI) during speech were observed in the luteal phase relative to other phases, while greater increases in epinephrine (EPI) was observed during the late follicular and luteal phases compared to the early follicular phase. Luteal phase estradiol predicted luteal EPI reactivity but not CI or VRI reactivity, while luteal phase EPI reactivity predicted luteal phase CI and VRI reactivity. Thus, cycle-related changes in EPI reactivity may be a stronger determinant of cycle effects on hemodynamic reactivity than sex hormones per se.

Hormones, heart disease, and health: individualized medicine versus throwing the baby out with the bathwater

It is increasingly axiomatic that depression has widespread adverse physiological effects and, conversely, that a variety of physiological systems impact the risk for developing depression. This convergence of depression and altered physiology is particularly dramatic during midlife--a time during which reproductive failure presages dramatic increases in prevalence of both heart disease and depression. The potentially meaningful and illuminating links between estrogen deficiency, cardiovascular disease (CVD), and depression have largely been obscured, first by assertions, subsequently repudiated, that the perimenopause was not a time of increased risk of depression, and more recently by the denegration of hormone replacement therapy by initial reports of the Women's Health Initiative. Increasingly, however, research has led to unavoidable conclusions that CVD and depression share common, mediating pathogenic processes and that these same processes are dramatically altered by the presence or absence of estrogen (E2). This review summarizes data supporting these contentions with the intent of placing depression and estrogen therapy in their proper physiologic context.

Hormones, heart disease, and health: individualized medicine versus throwing the baby out with the bathwater

It is increasingly axiomatic that depression has widespread adverse physiological effects, and conversely that a variety of physiological systems impact the risk for developing depression. This convergence of depression and altered physiology is particularly dramatic during midlife-a time during which reproductive failure presages dramatic increases in prevalence of both heart disease and depression. The potentially meaningful and illuminating links between estrogen (E2) deficiency, cardiovascular disease (CVD), and depression have largely been obscured, first by assertions, subsequently repudiated that the perimenopause was not a time of increased risk of depression, and more recently by the denegration of hormone replacement therapy by initial reports of the Women's Health Initiative. Increasingly, however, research has led to unavoidable conclusions that CVD and depression share common and mediating pathogenic processes and that these same processes are dramatically altered by the presence or absence of E2. This review summarizes data supporting this contention with the intent of placing depression and E2 therapy in their proper physiologic context.

Effects of estrogen plus progesterone on hemodynamic and vascular reactivity in hypertensive postmenopausal women

AIMS

To investigate the medium-term effects of estrogen plus progesterone therapy (EPT) on vascular reactivity, endothelial function and hemodynamic responses in 20 hypertensive postmenopausal women.

METHODS

This randomized, double-blind, cross-over, placebo-controlled study investigates the effect of 6 months of EPT (conjugated equine estrogen plus medroxyprogesterone). Blood pressure (office and ambulatory), heart rate and heart rate variability (HRV) were measured at baseline and following EPT/placebo treatment. In eight women, we used a wire-myograph to assess endothelial function and contractile response of subcutaneous arteries to transmural nerve stimulation (TNS) and exogenous noradrenaline.

RESULTS

EPT decreased vascular reactivity to cumulative TNS compared with baseline (p<0.01) and placebo (p<0.05). Moreover, EPT diminished sensitivity to exogenous noradrenaline (p<0.05). Although EPT reinforced response to acetylcholine, we observed no difference in maximal relaxation induced by substance P or acetylcholine. EPT did not affect ambulatory blood pressure, heart rate or HRV.

CONCLUSIONS

Oral combined medium-term EPT reduces adrenergic reactivity in subcutaneous arteries from treated hypertensive postmenopausal women. EPT might act postjunctionally at the adrenergic vascular receptor level. In the present study, EPT neither reduces sympathetic activity nor increases vagal tone, and thus does not support an effect on the central hemodynamic system.

Sex/gender medicine. The biological basis for personalized care in cardiovascular medicine

Sex differences in morbidity and mortality associated with cardiovascular disease have been recognized by the medical community for decades. Investigation into the underlying biological basis of these differences was largely neglected by the scientific community until a report released by the Institute of Medicine in the United States in 2001 "Exploring the Biological Contributions to Human Health: Does Sex Matter?" Recommendations from this report included the need for more accurate use of the terms "sex" and "gender", better tools and resources to study the biological basis of sex differences, integration of findings from different levels of biological organization and continued synergy between basic and clinical researchers. Ten years after the Institute's report, this review evaluates some of the sex differences in cardiovascular disease, reviews new approaches to study sex differences and emphasizes areas where further research is required. In the era of personalized medicine, the study of the biological basis of sex differences promises to optimize preventive, diagnostic and therapeutic strategies for cardiovascular disease in men and women, but will require diligence by the scientific and medical communities to remember that sex does matter.

Transdermal hormone therapy and bone health

The clinical aftermath of the reporting of the initial findings of the Women's Health Initiative (WHI) in 2002 was a profound reduction in the use of hormone therapies by menopausal women. This reduction led to a well documented increase in vasomotor symptoms and vaginal atrophy among those women who discontinued their hormone regimens. However, another adverse impact among these women, as well as many other menopausal women, is the well recognized increased likelihood of osteoporosis resulting from the decline in circulating estradiol levels associated with natural and surgical menopause. Although the use ofnon-hormonal drugs such as bisphosphonates has been shown to reduce the risk of fracture in women with osteoporosis, bisphosphonates have not been shown to reduce the risk of fracture in non-osteoporotic women. Indeed, only oral estrogen (as demonstrated in the WHI studies) has been shown to reduce the risk of fracture in osteoporotic and non-osteoporotic women. As non-oral hormone therapies have been shown to be as effective in treating vasomotor symptoms and vulvovaginal atrophy and to have a different (and perhaps more beneficial) physiological effect than oral regimens, it behooves us to assess the impact of non-oral hormone regimens on bone mineral density and fracture risk. Although there are no clinical trials that primarily assess the impact of non-oral regimens on fracture risk in menopausal women, numerous studies are consistent in demonstrating the positive impact of non-oral regimens in maintaining and increasing bone mineral density among users, even for those women using estrogen doses that are considered to be "too low" to have a beneficial impact on other menopausal symptoms.

Vascular actions of estrogens: functional implications

The impact of estrogen exposure in preventing or treating cardiovascular disease is controversial. But it is clear that estrogen has important effects on vascular physiology and pathophysiology, with potential therapeutic implications. Therefore, the goal of this review is to summarize, using an integrated approach, current knowledge of the vascular effects of estrogen, both in humans and in experimental animals. Aspects of estrogen synthesis and receptors, as well as general mechanisms of estrogenic action are reviewed with an emphasis on issues particularly relevant to the vascular system. Recent understanding of the impact of estrogen on mitochondrial function suggests that the longer lifespan of women compared with men may depend in part on the ability of estrogen to decrease production of reactive oxygen species in mitochondria. Mechanisms by which estrogen increases endothelial vasodilator function, promotes angiogenesis, and modulates autonomic function are summarized. Key aspects of the relevant pathophysiology of inflammation, atherosclerosis, stroke, migraine, and thrombosis are reviewed concerning current knowledge of estrogenic effects. A number of emerging concepts are addressed throughout. These include the importance of estrogenic formulation and route of administration and the impact of genetic polymorphisms, either in estrogen receptors or in enzymes responsible for estrogen metabolism, on responsiveness to hormone treatment. The importance of local metabolism of estrogenic precursors and the impact of timing for initiation of treatment and its duration are also considered. Although consensus opinions are emphasized, controversial views are presented to stimulate future research.

Estrogen and hypertension

Menopause is accompanied by a dramatic rise in the prevalence of hypertension in women, suggesting a protective role of endogenous estradiol on blood pressure (BP). Both animal experimental and human clinical investigations suggest that estrogen engages several mechanisms that protect against hypertension, such as activation of the vasodilator pathway mediated by nitric oxide and prostacyclin and inhibition of the vasoconstrictor pathway mediated by the sympathetic nervous system and angiotensin. However, emerging evidence from recent clinical trials indicates a small increase, rather than decrease, in systolic BP with oral estrogen administration in postmenopausal women, without any detectable effect on diastolic BP. Mechanisms underlying this selective rise in systolic BP in postmenopausal women and oral contraceptive-induced hypertension in premenopausal women remain unknown, but the rise may be related to supraphysiologic concentration of estrogen in the liver. To date, transdermal delivery of estrogen, which avoids the first-pass hepatic metabolism of estradiol, appears to have a small BP-lowering effect in postmenopausal women and may be a safer alternative in hypertensive women.

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.

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.

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.

Oxytocinergic activity is linked to lower blood pressure and vascular resistance during stress in postmenopausal women on estrogen replacement

Estrogen administration results in increased release of the oxytocin (OT) prohormone reflected by increases in oxytocin intermediate peptide (OT Int) in both animal models and humans, and sequential treatment of ovariectomized rats with estrogen/progesterone then progesterone withdrawal leads to increased hypothalamic OT mRNA. Blood pressure (BP) reductions have been related to increased exogenous and endogenous OT in rats and to higher endogenous OT activity in premenopausal women, but not previously in postmenopausal women. Thus, we used plasma obtained at rest and during a speech stressor from 54 postmenopausal women who participated in a 6-month randomized trial of oral conjugated estrogens vs. placebo to examine effects of estrogen replacement therapy (ERT) on plasma OT and OT Int levels and their relationships to changes in BP during the trial. ERT alone and with progesterone (but not placebo) led to significant increases in plasma levels of OT Int, but no change in plasma OT levels. Women showing greater increases in OT Int during treatment showed greater decreases in BP and total vascular resistance during a series of behavioral stressors compared to women with moderate or no increases in OT Int, even after controlling for effects related to treatment condition or to changes in plasma estradiol. The findings suggest that enhanced oxytocinergic activity may contribute to BP decreases associated with ERT in more responsive postmenopausal women.

Effect of hormone therapy on the elastic properties of the arteries in healthy postmenopausal women

The aim of the study was to assess the effect of continuous hormone therapy (HT) for 1 yr on pulse wave analysis and central aortic pressure in healthy postmenopausal women. Sixty-five healthy postmenopausal women were randomly allocated to receive either conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA, Premelle 5, Wyeth-Ayerst Lab, Philadelphia, PA, no.=32) or no therapy (no.=33). Treatment was continuous, and the study period lasted 12 months. Central aortic pressure, augmentation and augmentation index (AI) were determined non-invasively using applanation tonometry. All measurements were performed at baseline and at the end of the study by the same person. Ns differences were found between baseline values and values at the end of the study in either the control or the CEE/MPA group in central systolic aortic pressure (107.0 +/- 13.1 vs 107.6 +/- 11.3 mmHg, p=0.80, and 110.8 +/- 10.8 vs 112.3 +/- 11.4 mmHg, p=0.23, respectively), augmentation (12.6 +/- 4.2 vs 11.9 +/- 4.8 mmHg, p=0.45 and 11.7 +/- 3.7 vs 12.6 +/- 4.2 mmHg, p=0.34, respectively), and percentage of AI (36.8 +/- 9.3 vs 36.3 +/- 10.3, p=0.81 and 34.1 +/- 8.9 vs 34.9 +/- 9.8, p=0.72, respectively). The results of this preliminary report suggest that HT for 1 yr does not have any significant effect on central aortic pressure and wave reflection in healthy postmenopausal women.

Influence of hormone therapy on the cardiovascular responses to stress of postmenopausal women

Epidemiological and psychophysiological data suggest that groups that differ in reproductive hormones and stress responses also differ in risk for cardiovascular disease. To evaluate the effects of hormone therapy on women's cardiovascular responses to laboratory stressors, 89 healthy postmenopausal women were tested twice, before and after exposure for about 8 weeks to one of the five conditions: placebo, Estratab (primarily estrone), Estratab plus Prometrium (micronized progesterone), Estratab plus Provera (synthetic progestin), and Estratest (same estrogen as in Estratab plus methyltestosterone). Results showed that women assigned to Estratab plus Prometrium and Estratest had diminished systolic blood pressure responses to stress upon retesting, whereas the other groups did not change in the level of their responses. Women assigned to Estratab plus Prometrium had diminished diastolic blood pressure responses during a speech stressor upon retesting, whereas women assigned to Estratab plus Provera increased. Our findings show that hormone therapy does affect women's stress responses, but they do not provide a simple explanation as to why groups at high and low risk for cardiovascular disease differ in reproductive hormones and stress responses.

17β-Estradiol/levonorgestrel transdermal system for the management of the symptomatic menopausal woman

Recent publications of the initial outcomes from the Women's Health Initiative (WHI) study of menopausal management have raised concerns over the safety of hormone therapy [1,2]. Every study, no matter how large or well conducted, has biases and limitations that preclude the ability to apply the outcomes to a larger group of individuals not specifically evaluated in the analysis. In particular, the hormonal arms of the WHI evaluated only a single dose of a daily oral regimen of conjugated equine oestrogen 0.625 mg [1,2], combined with medroxyprogesterone acetate 2.5 mg if the subject had a uterus [1]. The failure to evaluate non-oral regimens prevented the evaluation of hormone delivery systems that have been shown to provide similar symptom relief to oral regimens, but with a considerably different physiological impact. The once-weekly transdermal patch (Climara Pro releasing 17beta-estradiol 0.045 mg/day and levonorgestrel 0.015 mg/day has been shown to be highly effective in rapidly reducing the frequency and intensity of vasomotor symptoms and to significantly improve all categories in the quality of life Women's Health Questionnaire [3]. In addition, this transdermal combination system was not associated with any cases of endometrial hyperplasia, adverse impacts on cholesterol or lipid values and was associated with an increasing rate of amenorrhoea over time [3]. The 17beta-estradiol/levonorgestrel transdermal system is approved in the US for the treatment of moderate-to-severe vasomotor symptoms and the prevention and treatment of urogenital atrophy.

Estrogens and Neuropeptides in Raynaud's Phenomenon

Raynaud's phenomenon (RP) is characterized by ischemia and reperfusion of the extremities. Vasomotor instability is due to a microcirculatory disturbance that may be linked to different events involving the endothelium or peripheral nerve terminals. Endothelium and nerve endings "sense" the modifications of the microenvironment and both of them release factors that contribute to find a balance between vasolidation and vasoconstriction. Moreover, estrogens may contribute to control vascular tone regulating finger skin circulation. A loss of neuropeptides has been shown in secondary RP where supplementation with factors derived from nerve endings has been demonstrated to induce a potent vasolidation. Estrogen administration improved endothelial dysfunction in secondary RP. Neuropeptides and estrogens thus share the endothelial-dependent pathway, usually mediated by nitric oxide, in inducing vasolidation. The network directed by the endothelium is in reality controlled by a neuro-hormonal axis composed by neuropeptides and estrogens. This delicate balance keeps the vascular tone, and its dysfunction may lead to a dysregulation of vascular tone, manifest in clinics as a primary or secondary RP.