Plasma prolactin level and risk of incident hypertension in postmenopausal women

Rationality of the ethanol precipitation process in modern preparation production of Zishui-Qinggan decoction evaluated by integrating UPLC-QTOF-MS/MS-based chemical profiling/serum pharmacochemistry and network pharmacology

INTRODUCTION

Zishui-Qinggan decoction (ZQD) is a classical traditional Chinese medicine formula (TCMF) for alleviating menopausal symptoms (MPS) induced by endocrine therapy in breast cancer patients. In the production of TCMF modern preparations, ethanol precipitation (EP) is a commonly but not fully verified refining process.

OBJECTIVES

Chemical profiling/serum pharmacochemistry and network pharmacology approaches were integrated for exploring the rationality of the EP process in the production of ZQD modern preparations.

MATERIAL AND METHODS

Ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) was applied to identify the chemical profiles and absorbed components of ZQD. Network pharmacology was used to identify targets and pathways related to MPS-relieving efficacy.

RESULTS

The chemicals of ZQDs without/with EP process (referred to as ZQD-W and ZQD-W-P, respectively) were qualitatively similar with 89 and 87 components identified, respectively, but their relative contents were different; 51 components were detectable in the serum of rats orally administered with ZQD-W, whereas only 19 were detected in that administered with ZQD-W-P. Key targets, such as AKT1, and pathways, such as the PI3K-Akt signalling pathway, affected by ZQD-W and ZQD-W-P were similar, while the neuroactive ligand-receptor interaction pathway among others and the MAPK signalling pathway among others were specific pathways affected by ZQD-W and ZQD-W-P, respectively. The specifically absorbed components of ZQD-W could combine its specific key targets.

CONCLUSION

The EP process quantitatively altered the chemical profiles of ZQD, subsequently affected the absorbed components of ZQD, and then affected the key targets and pathways of ZQD for relieving MPS. The EP process might result in variation of the MPS-relieving efficacy of ZQD, which deserves further in vivo verification.

Alternations of Blood Pressure Following Surgical or Drug Therapy for Prolactinomas

Several subtypes of pituitary neuroendocrine tumors (PitNETs), such as acromegaly and Cushing's disease, can result in hypertension. However, whether prolactinoma is associated with this complication remains unknown. Moreover, the effect of treatment with surgery or drugs on blood pressure (BP) is unknown. Herein, a retrospective study reviewed 162 patients with prolactinoma who underwent transsphenoidal surgery between January 2005 and December 2022. BP measurements were performed 1 day before and 5 days after surgery. Accordingly, patients' medical characteristics were recorded. In addition, in situ rat and xenograft nude-mice prolactinoma models have been used to mimic prolactinoma. In vivo BP and serum prolactin (PRL) levels were measured after cabergoline (CAB) administration in both rats and mice. Our data suggest that surgery can effectively decrease BP in prolactinoma patients with or without hypertension. The BP-lowering effect was significantly associated with several variables, including age, sex, disease duration, tumor size, invasion, dopamine agonists (DAs)-resistance, recurrence, and preoperative PRL levels. Moreover, in situ and xenograft prolactinomas induced BP elevation, which was alleviated by CAB treatment without and with a statistical difference in rats and mice, respectively. Thus, surgery or CAB can decrease BP in prolactinoma, indicating that pre- and postoperative BP management becomes essential.

Metabolic Syndrome Components in Patients with Pituitary Adenoma

Pituitary adenomas are benign tumors of the anterior portion of the pituitary gland (adenohypophysis), representing the 25% of all the tumor alterations. Pituitary adenomas are classified by the type of hormone secreted, cellularity, size, and structural alterations by the hormonal segregation. The diagnosis consists on the histopathological identification of cell types and the image-guided by magnetic resonance or tomography; the treatment can be both pharmacological and surgical. Metabolic Syndrome is the set of clinical conditions that increase the risk of cardiovascular diseases with an estimated prevalence of 25% worldwide. The alterations of metabolic syndrome are obesity, hypertension, dyslipidemia, insulin resistance, and diabetes mellitus type II. Pituitary adenomas and metabolic syndrome have an important relationship, hormone-secreting by pituitary adenomas affects a myriad of signaling pathways, which allows a favorable environment for the appearance of the metabolic syndrome. Moreover, patients with pituitary adenomas are shown to have an improvement in metabolic parameters after the medical/surgical treatment. The objective of this review is to explore the possible mechanisms through which PAs contributes to MetSx.

Breastfeeding initiation and duration among people with mild chronic hypertension: a secondary analysis of the Chronic Hypertension and Pregnancy trial

BACKGROUND

Increased duration of breastfeeding improves maternal cardiovascular health and may be especially beneficial in high-risk populations, such as those with chronic hypertension. Others have shown that individuals with hypertension are less likely to breastfeed, and there has been limited research aimed at supporting breastfeeding goals in this population. The impact of perinatal blood pressure control on breastfeeding outcomes among people with chronic hypertension is unknown.

OBJECTIVE

This study aimed to evaluate whether breastfeeding initiation and short-term duration assessed at the postpartum clinic visit differed according to perinatal blood pressure treatment strategy (targeting blood pressure <140/90 mm Hg vs reserving antihypertensive treatment for blood pressure ≥160/105 mm Hg).

STUDY DESIGN

We performed a secondary analysis of the Chronic Hypertension and Pregnancy trial. This was an open-label, multicenter, randomized trial where pregnant participants with mild chronic hypertension were randomized to receive antihypertensive medications with goal blood pressure <140/90 mm Hg (active treatment) or deferred treatment until blood pressure ≥160/105 mm Hg (control). The primary outcome was initiation and duration of breastfeeding, assessed at the postpartum clinic visit. We performed bivariate analyses and log-binomial and cumulative logit regression models, adjusting models for variables that were unbalanced in bivariate analyses. We performed additional analyses to explore the relationship between breastfeeding duration and blood pressure measurements at the postpartum visit.

RESULTS

Of the 2408 participants from the Chronic Hypertension and Pregnancy trial, 1444 (60%) attended the postpartum study visit and provided breastfeeding information. Participants in the active treatment group had different body mass index class distribution and earlier gestational age at enrollment, and (by design) were more often discharged on antihypertensives. Breastfeeding outcomes did not differ significantly by treatment group. In the active and control treatment groups, 563 (77.5%) and 561 (78.1%) initiated breastfeeding, and mean durations of breastfeeding were 6.5±2.3 and 6.3±2.1 weeks, respectively. The probability of ever breastfeeding (adjusted relative risk, 0.99; 95% confidence interval, 0.93-1.05), current breastfeeding at postpartum visit (adjusted relative risk, 1.01; 95% confidence interval, 0.94-1.10), and weeks of breastfeeding (adjusted odds ratio, 0.87; 95% confidence interval, 0.68-1.12) did not differ by treatment group. Increased duration (≥2 vs <2 weeks) of breastfeeding was associated with slightly lower blood pressure measurements at the postpartum visit, but these differences were not significant in adjusted models.

CONCLUSION

In a secondary analysis of the cohort of Chronic Hypertension and Pregnancy trial participants who attended the postpartum study visit and provided breastfeeding information (60% of original trial participants), breastfeeding outcomes did not differ significantly by treatment group. This suggests that maintaining goal blood pressure <140/90 mm Hg throughout the perinatal period is associated with neither harm nor benefit for short-term breastfeeding goals. Further study is needed to understand long-term breastfeeding outcomes among individuals with chronic hypertension and how to support this population in achieving their breastfeeding goals.

Efficacy and safety profiles of mood stabilizers and antipsychotics for bipolar depression: a systematic review

The whole picture of psychotropics for bipolar depression (BPD) remains unclear. This review compares the differences in efficacy and safety profiles among common psychotropics for BPD. MEDLINE, EMBASE, and PsycINFO were searched for proper studies. The changes in the depressive rating scale, remission/response rates, nervous system adverse events (NSAEs), gastrointestinal adverse events (GIAEs), metabolic parameters, and prolactin were compared between medication and placebo or among medications with the Cohen's d or number needed to treat/harm. The search provided 10 psychotropics for comparison. Atypical antipsychotics (AAPs) were superior to lithium and lamotrigine at alleviating acute depressive symptoms. Lithium was more likely to induce dry mouth and nausea. Cariprazine and aripiprazole seemed to be associated with an increased risk of akathisia and upper GIAEs. Lurasidone was associated with an increased risk of developing akathisia and hyperprolactinemia. Olanzapine, olanzapine-fluoxetine combination (OFC), and quetiapine were associated with an increased risk of NSAEs, metabolic risk, dry mouth, and constipation. Cariprazine, lurasidone, OFC, or quetiapine was optimal monotherapy for BPD. Further studies are needed to assess the efficacy and safety of lamotrigine for treating BPD. Adverse events varied widely across different drug types due to variations in psychopharmacological mechanisms, dosages, titration, and ethnicities.

The Involvement of Prolactin in Stress-Related Disorders

The most important and widely studied role of prolactin (PRL) is its modulation of stress responses during pregnancy and lactation. PRL acts as a neuropeptide to support physiological reproductive responses. The effects of PRL on the nervous system contribute to a wide range of changes in the female brain during pregnancy and the inhibition of the hypothalamic-pituitary axis. All these changes contribute to the behavioral and physiological adaptations of a young mother to enable reproductive success. PRL-driven brain adaptations are also crucial for regulating maternal emotionality and well-being. Hyperprolactinemia (elevated PRL levels) is a natural and beneficial phenomenon during pregnancy and lactation. However, in other situations, it is often associated with serious endocrine disorders, such as ovulation suppression, which results in a lack of offspring. This introductory example shows how complex this hormone is. In this review, we focus on the different roles of PRL in the body and emphasize the results obtained from animal models of neuropsychiatric disorders.

Cross-sectional association between prolactin levels and non-alcoholic fatty liver disease in patients with type 2 diabetes mellitus: a retrospective analysis of patients from a single hospital in China

OBJECTIVE

This study aimed to retrospectively assess the association between prolactin (PRL) and non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM).

DESIGN AND SETTING

A retrospective, cross-sectional study was conducted at a single hospital in Anhui, China.

PARTICIPANTS

A total of 406 patients with T2DM (230 men and 176 women) was included.

OUTCOME MEASURES

P values for the independent t-test, the Mann-Whitney rank-sum test, the Spearman correlation analysis and multiple logistic regression models were used to explore the association between PRL and NAFLD in patients with T2DM.

RESULTS

The results indicated that in both men and women, the levels of PRL were significantly lower in the T2DM with NAFLD group than in the T2DM without NAFLD group (men: 9.56 ng/mL vs 10.36 ng/mL, women: 10.38 ng/mL vs 12.97 ng/mL). In male patients, the levels of PRL were negatively correlated with hip circumference (r=-0.141, p=0.032), homoeostasis model assessment for insulin resistance (C-peptide) (r=-0.141, p=0.032) and triglyceride (TG) (r=-0.252, p=0.000) values and inversely correlated with high-density lipoprotein (r=0.147, p=0.025) levels. In female patients, PRL levels were negatively related to body mass index (r=-0.192, p=0.011), diastolic blood pressure (r=-0.220, p=0.003), waist circumference (r=-0.152, p=0.044), hip circumference (r=-0.157, p=0.037) and TG (r=-0.258, p=0.001) values. Logistic regression analysis revealed a negative relationship between PRL and NAFLD (men: OR 0.891, 95% CI 0.803 to 0.989, p=0.031; women: OR 0.874, 95% CI 0.797 to 0.957, p=0.004). As PRL levels increased, NAFLD prevalence decreased in both sexes (men: p=0.012, women: p=0.013).

CONCLUSION

Our results suggest that low levels of PRL in the physiological range were markers of NAFLD in patients with T2DM and that PRL within the biologically high range may play a protective role in the pathogenesis of NAFLD.

The role of prolactin/vasoinhibins in cardiovascular diseases

Prolactin (PRL) is a polypeptide hormone that is mainly synthesized and secreted by the lactotroph cells of the pituitary. There are two main isoforms of PRL: 23-kDa PRL (named full-length PRL) and vasoinhibins (including 5.6-18 kDa fragments). Both act as circulating hormones and cytokines to stimulate or inhibit vascular formation at different stages and neovascularization, including endothelial cell proliferation and migration, protease production, and apoptosis. However, their effects on vascular function and cardiovascular diseases are different or even contrary. In addition to the structure, secretion regulation, and signal transduction of PRL/vasoinhibins, this review focuses on the pathological mechanism and clinical significance of PRL/vasoinhibins in cardiovascular diseases.

Recent findings on hyperprolactinemia and its pathological implications: a literature review

The prolactin hormone (PRL) is often secreted by lactotrophic cells of the anterior pituitary and has been shown to play a role in various biological processes, including breast feeding and reproduction. The predominant form of this hormone is the 23 kDa form and acts through its receptor (PRLR) on the cell membrane. This receptor is a member of the superfamily of hematopoietic/cytokine receptors. PRL also has a 16 kDa subunit with anti-angiogenic, proapoptotic, and anti-inflammatory effects which is produced by the proteolytic breakdown of this hormone under oxidative stress. Although the common side effects of hyperprolactinemia are exerted on the reproductive system, new studies have shown that hyperprolactinemia has a wide variety of effects, including playing a role in the development of autoimmune diseases and increasing the risk of cardiovascular disease, peripartum cardiomyopathy, and diabetes among others. The range of PRL functions is increasing with the discovery of multiple sites of PRL secretion as well as PRLR expression in various tissues. This review summarizes current knowledge of the biology of PRL and its receptor, as well as the role of PRL in human pathophysiology.

The interplay between prolactin and cardiovascular disease

Hyperprolactinemia can be caused by several conditions and its effects on the hypothalamic-pituitary-gonadal axis are understood in more detail. Nevertheless, in recent decades, other metabolic effects have been studied and data pointed to a potential increased cardiovascular disease (CVD) risk. A recent study showed a decrease in total and LDL- cholesterol only in men with prolactinoma treated with dopamine agonists (DA) supporting the previous results of a population study with increased CVD risk in men harboring prolactinoma. However, other population studies did not find a correlation between prolactin (PRL) levels and CVD risk or mortality. There is also data pointing to an increase in high-density lipoprotein levels, and decreases in triglycerides, carotid-intima-media thickness, C-reactive protein, and homocysteine levels in patients with prolactinoma on DA treatment. PRL was also implicated in endothelial dysfunction in pre and postmenopausal women. Withdrawal of DA resulted in negative changes in vascular parameters and an increase in plasma fibrinogen. It has been shown that PRL levels were positively correlated with blood pressure and inversely correlated with dilatation of the brachial artery and insulin sensitivity, increased homocysteine levels, and elevated D-dimer levels. Regarding possible mechanisms for the association between hyperprolactinemia and CVD risk, they include a possible direct effect of PRL, hypogonadism, and even effects of DA treatment, independently of changes in PRL levels. In conclusion, hyperprolactinemia seems to be associated with impaired endothelial function and DA treatment could improve CVD risk. More studies evaluating CVD risk in hyperprolactinemic patients are important to define a potential indication of treatment beyond hypogonadism.

Pituitary Dysfunction as a Cause of Cardiovascular Disease

The hypothalamic-pituitary axis is responsible for the neuroendocrine control of several organ systems. The anterior pituitary directly affects the functions of the thyroid gland, the adrenal glands, and gonads, and regulates growth and milk production. The posterior hypophysis, through nerve connections with the hypothalamic nuclei, releases vasopressin and oxytocin responsible for water balance and social bonding, sexual reproduction and childbirth, respectively. Pituitary gland hormonal excess or deficiency results in dysregulation of metabolic pathways and mechanisms that are important for the homeostasis of the organism and are associated with increased morbidity and mortality. Cardiovascular (CV) disorders are common in pituitary disease and have a significant impact on survival. Hormonal imbalance is associated with CV complications either through direct effects on the heart structure and function and vasculature or indirectly by altering the metabolic profile. Optimal endocrine control can prevent or reverse CV defects and preserve survival and quality of life. In this review, we discuss the effects of pituitary hormone excess and deficiency on the CV system. Specifically, we assess the impact of Somatotroph, Corticotroph, Gonadotroph, and Lactotroph anterior pituitary axes on the CV system. The effect of posterior pituitary function on the CV system is also explored.

Hyperprolactinaemia

Hyperprolactinaemia is one of the most common problems in clinical endocrinology. It relates with various aetiologies (physiological, pharmacological, pathological), the clarification of which requires careful history taking and clinical assessment. Analytical issues (presence of macroprolactin or of the hook effect) need to be taken into account when interpreting the prolactin values. Medications and sellar/parasellar masses (prolactin secreting or acting through “stalk effect”) are the most common causes of pathological hyperprolactinaemia. Hypogonadism and galactorrhoea are well-recognized manifestations of prolactin excess, although its implications on bone health, metabolism and immune system are also expanding. Treatment mainly aims at restoration and maintenance of normal gonadal function/fertility, and prevention of osteoporosis; further specific management strategies depend on the underlying cause. In this review, we provide an update on the diagnostic and management approaches for the patient with hyperprolactinaemia and on the current data looking at the impact of high prolactin on metabolism, cardiovascular and immune systems.

Metabolic effects of dopamine agonists in patients with prolactinomas: a systematic review and meta-analysis

OBJECTIVES

Recent large cohort studies suggest an association between high plasma prolactin and cardiovascular mortality. The objective of this systematic review was to systematically assess the effect of reducing prolactin with dopamine agonist on established cardiovascular risk factors in patients with prolactinomas.

DESIGN

Bibliographical search was done until February 2019 searching the following databases: PubMed, EMBASE, WHO and LILAC. Eligible studies had to include participants with verified prolactinomas where metabolic variables were assessed before and after at least 2 weeks treatment with dopamine agonists.

METHODS

Baseline data and outcomes were independently collected by two investigators. The study was registered with PROSPERO (registration number CRD42016046525).

RESULTS

Fourteen observational studies enrolling 387 participants were included. The pooled standardized mean difference of the primary outcome revealed a reduction of BMI and weight of -0.21 (95% CI -0.37 to -0.05; P = 0.01; I2 = 71%), after treatment. Subgroup analysis suggested that the reduction of weight was primarily driven by studies with high prolactin levels at baseline (P = 0.04). Secondary outcomes suggested a small decrease in waist circumference, a small-to-moderate decrease in triglycerides, fasting glucose levels, HOMA-IR, HbA1c and hsCRP, and a moderate decrease in LDL, total cholesterol and insulin.

CONCLUSION

This systematic review suggests a reduction of weight as well as an improved lipid profile and glucose tolerance after treatment with dopamine agonist in patients with prolactinomas. These data are based on low-quality evidence.

Evidence for hyperprolactinemia in migraineurs: a systematic review and meta-analysis

BACKGROUND

One of the hypothalamus-pituitary axis hormones which may play a crucial role in pathophysiology of migraine is prolactin which is secreted from anterior pituitary gland and synthesized by various immune system cells as well. Whether prolactin blood levels can affect the migraine pathogenesis is an open question. Therefore, investigating prolactin circulatory levels in migraineurs may pave the way to underpin the mechanisms of migraine pathophysiology at biochemical levels. In the current investigation, the prolactin blood levels in the migraine subjects were investigated using systematic review and meta-analysis.

METHODS

Using online and specialized biomedical databases including Google Scholar, Medline, Pubmed, Pubmed Central, Embase, and Scopus, without the beginning date restriction until Feb 2019, the systematic review retrieved 11 publications in this systematic review after fulfilling for the inclusion and exclusion criteria. For heterogeneity, extent calculation statistical testing was applied. In the present study, the levels of circulatory prolactin in migraineurs assessed using standardized mean difference (SMD) as the effect size.

RESULTS

Q quantity and I²% statistic index showed a high heterogeneity in the 13 selected publications (188.370 and 92.568, respectively) and random-effects model was chosen for further analyses. The meta-analysis on a total number of 460 migraineurs and 429 healthy controls found that the weighted pooled SMD for the effects of prolactin blood concentrations on migraine pathogenesis was as follows: SMD = 1.435 (95% confidence interval, 0.854-2.015).

CONCLUSION

The current investigation presents evidence that prolactin blood levels are higher in migraineurs than healthy subjects.

Lack of Relationships Between Serum Prolactin Concentrations and Classical Cardiovascular Risk Factors in Eastern Croatian Older Adults

Background

Relationships between serum prolactin concentrations and various CV risk factors in older adults have rarely been assessed. The aim of this study was to examine the relationships between serum prolactin concentrations and CV risk factors in older patients with multiple CV risk factors.

Material/Methods

This case-control study included 92 patients, 50–89 years old (median, 69 years), with multiple CV risk factors. We used data from general practice electronic health records and biochemical laboratory tests. Patients were divided according to categories of CV risk factors.

Results

Serum prolactin concentrations were significantly higher in elderly people (≤65 vs. >65) and in men (70.65±58.02 vs. 150.82±114.05 mIU/L), as well as in patients with lower renal function (156.70±127.23 vs. 72.53±37.25 mIU/L, the bottom vs. top quartile of creatinine clearance), higher serum homocysteine and TSH concentrations, and in those who used NSAID and statins. Parameters indicating chronic inflammation (CRP) and renal function decline (creatinine clearance) were significantly and independently correlated with increased serum prolactin concentrations in multiple regression analysis.

Conclusions

When assessing the relationships between prolactin and CV risk factors in older people with multiple CV risk factors, the effect of renal function decline and chronic inflammation should receive attention.

Association between serum prolactin levels and insulin resistance in non-diabetic men

Prolactin (PRL) has roles in various physiological functions. Although experimental studies showed that PRL has both beneficial and adverse effects on type 2 diabetes mellitus, clinical findings in subjects with hyperprolactinemia indicate adverse effects on glucose metabolism. However, effects of PRL within the physiological range in human are controversial. A population-based study of 370 Japanese men enrolled in the 2014 Iwaki study (aged 52.0 ± 14.8 years). In this cross-sectional study, associations between serum PRL levels and homeostatic model assessment (HOMA) indices representing glucose metabolism in a physiological setting were examined using multivariable regression analysis. Although univariate linear regression analyses showed significant associations between serum PRL levels and HOMA indices, adjustment with multiple factors made the association with HOMA-ß (insulin secretion) insignificant, while those with HOMA-R (insulin resistance) remained significant (ß = 0.084, p = 0.035). Non-linear regression analyses showed a regression curve with a peak at serum PRL level, 12.4 ng/mL and a positive association of serum PRL level with HOMA-R below the peak (ß = 0.119, p = 0.004). Higher serum PRL levels within the physiological range seem to be associated with insulin resistance in men.

Prolactin as a predictor of endothelial dysfunction and arterial stiffness progression in menopause

Postmenopausal women are at increased risk for progression of arteriosclerosis and hypertension. Recent cross-sectional evidence suggests that high normal circulating prolactin levels may accelerate vascular ageing in menopause. Postmenopausal women (n=201) were consecutively recruited from a Menopause Clinic and re-evaluated in at least one follow-up visit within the next 3 years. Baseline circulating prolactin levels were measured while both baseline and follow-up vascular and biochemical measurements were performed. Endothelial function was assessed by flow-mediated dilation (FMD), aortic stiffness by pulse-wave velocity (PWV) and arterial wave reflections by applanation tonometry. Baseline prolactin significantly correlated with lower FMD at follow-up (P=0.005). After multivariable adjustment for age, follow-up time, blood pressure (BP), body mass index, smoking and medication, this correlation remained significant (P=0.003). In addition, baseline circulating prolactin levels were independently associated with changes in mean BP (β=0.131, P=0.021), peripheral diastolic BP (β=0.169, P=0.004) and new-onset hypertension (OR=1.235, P=0.001). Owing to significant interaction between baseline prolactin and age for changes in PWV over time (P=0.036), a subgroup analysis based on median age was performed. This analysis revealed that in women younger than 55 years, prolactin was an independent predictor of changes in PWV over time (P=0.008). In conclusion, high normal circulating prolactin levels predict changes in haemodynamic indices and worsening endothelial function in healthy postmenopausal women. Particularly in young postmenopausal women, prolactin predicts accelerated arterial stiffening.

Prolactin alters blood pressure by modulating the activity of endothelial nitric oxide synthase

Increased levels of a cleaved form of prolactin (molecular weight 16 kDa) have been associated with preeclampsia. To study the effects of prolactin on blood pressure (BP), we generated male mice with a single-copy transgene (Tg; inserted into the hypoxanthine-guanine phosphoribosyltransferase locus) that enables inducible hepatic production of prolactin and its cleavage product. The Tg is driven by the indole-3-carbinol (I3C)-inducible rat cytochrome P450 1A1 promoter. When the Tg mice were fed normal chow (NC), plasma prolactin concentrations were comparable to those in female WT mice in the last third of pregnancy, and BP was lower than in WT mice (∼95 mm Hg vs. ∼105 mm Hg). When the Tg mice were fed chow containing IC3, plasma prolactin concentrations increased threefold, BP increased to ∼130 mm Hg, and cardiac function became markedly impaired. IC3 chow did not affect the WT mice. Urinary excretion of nitrite/nitrate and the amount of Ser1177-phosphorylated endothelial nitric oxide (NO) synthase (eNOS) were significantly greater in the Tg mice fed NC than in WT mice, as they are during pregnancy. However, when I3C was fed, these indicators of NO production became significantly less in the Tg mice than in WT mice. The effects of increased plasma prolactin were abolished by a genetic absence of eNOS. Thus, a threefold increase in plasma prolactin is sufficient to increase BP significantly and to markedly impair cardiac function, with effects mediated by NO produced by eNOS. We suggest that pregnant women with abnormally high prolactin levels may need special attention.

Recent advances in central cardiovascular control: sex, ROS, gas and inflammation

The central nervous system (CNS) in concert with the heart and vasculature is essential to maintaining cardiovascular (CV) homeostasis. In recent years, our understanding of CNS control of blood pressure regulation (and dysregulation leading to hypertension) has evolved substantially to include (i) the actions of signaling molecules that are not classically viewed as CV signaling molecules, some of which exert effects at CNS targets in a non-traditional manner, and (ii) CNS locations not traditionally viewed as central autonomic cardiovascular centers. This review summarizes recent work implicating immune signals and reproductive hormones, as well as gasotransmitters and reactive oxygen species in the pathogenesis of hypertension at traditional CV control centers. Additionally, recent work implicating non-conventional CNS structures in CV regulation is discussed.

Association Between Prolactin and Incidence of Cardiovascular Risk Factors in the Framingham Heart Study

BACKGROUND

Prolactin is an anterior pituitary hormone that may modulate the adverse effects of obesity. Prolactin has been associated with cardiovascular disease mortality, but less is known about whether prolactin predicts incidence of cardiovascular disease risk factors.

METHODS AND RESULTS

Our sample (n=3232, mean age 40.4 years, 52.1% women) was drawn from Framingham Heart Study participants who attended 2 examinations an average of 6.1 years apart. After excluding those with elevated prolactin (>30 mg/dL for women, >20 mg/dL for men), multivariable-adjusted regressions modeled the associations between baseline prolactin and changes in cardiovascular disease risk factors. Models were adjusted for age, sex, baseline value of the risk factor, smoking status, hormone replacement therapy, and menopausal status and additionally for body mass index. Mean prolactin levels were 11.9 mg/dL (SD 5.2) in women and 8.0 mg/dL (SD 2.9) in men. No associations were observed for change in weight, body composition, total cholesterol, triglycerides, or fasting glucose. In women, for example, for each 5-mg/dL increment in prolactin, odds of incident hypercholesterolemia were 1.06, which was not significant (95% CI 0.91-1.23, P=0.46). Some exceptions were of note. In women, for each 5-mg/dL increment in prolactin, we observed increased odds of low high-density lipoprotein cholesterol at follow-up (odds ratio 1.50, 95% CI 1.18-1.91, P=0.001) that persisted after adjustment for body mass index (P=0.001). In men, a 5-mg/dL increment in prolactin was associated with increased odds of incident hypertension (odds ratio 1.61, 95% CI 1.18-2.20 P=0.002) and incident diabetes (odds ratio 1.70, 95% CI 1.04-2.78, P=0.03).

CONCLUSIONS

Prolactin is not associated with a comprehensive panel of incident cardiovascular disease risk factors. Measurement of circulating prolactin levels in the community likely does not provide substantial insight into cardiometabolic risk.

Hyperprolactinemia: pathophysiology and therapeutic approach

Prolactin (PRL) is a hormone, mainly secreted by lactotroph cells of the anterior pituitary gland. Recent studies have shown it may also be produced by many extrapituitary cells. Its well-recognized PRL plays an important role in lactation during pregnancy, but it is involved in other biological functions such as angiogenesis, immunoregulation and osmoregulation. Hyperprolactinemia is a typical condition producing reproductive dysfunction in both sexes, resulting in hypogonadism, infertility and galactorrhea. It may be also asymptomatic. Lactotroph adenomas (prolactinoma) is one of the most common cause of PRL excess, representing approximately 40% of all pituitary tumors. Several other conditions should be excluded before a clear diagnosis of hyperprolactinemia is made. Hyperprolactinemia may be secondary to pharmacological or pathological interruption of hypothalamic-pituitary dopaminergic pathways or idiopathic. Stress, renal failure or hypothyroidism are other frequent conditions to exclude in patients with hyperprolactinemia. We will review biochemical characteristics and physiological functions of that hormone. Clinical and pharmacological approach to hyperprolactinemia will also be discussed.

The association between prolactin, high-sensitivity C-reactive protein and Framingham risk score in menopause

AIMS

To evaluate the association between serum prolactin, high-sensitivity C-reactive protein (hs-CRP) levels and cardiovascular disease risk in postmenopausal women regarding the Framingham Risk Score (FRS).

METHODS

Fifty-eight menopausal women were enrolled into the cross-sectional study. All participants had 24-hour ambulatory blood pressure monitoring, echocardiography, electrocardiography, and carotid intima-media thickness measurement. Blood samples were obtained for prolactin, hs-CRP, lipid profile, fasting glucose, and insulin.

RESULTS

Among the participants, 67.24% had a FRS <10%, and 32.75% had a FRS ≥10%. Levels of prolactin and hs-CRP did not differ between the FRS groups. In the FRS <10% group, significantly higher levels of prolactin were found. Cases with hypertension have significantly higher levels of hs-CRP. Prolactin and hs-CRP were found to be associated with hypertension in the FRS <10% and ≥10% groups, respectively.

CONCLUSIONS

Hypertensive postmenopausal women with low risk for cardiovascular diseases have increased levels of prolactin, suggesting a possible role in the pathogenesis of hypertension. The correlation of hs-CRP with systolic blood pressure can be interpreted as a potential effect of hypertensive heart disease reflecting a state of high-risk milieu with elevated inflammatory markers.

High prolactin levels are independently associated with damage accrual in systemic lupus erythematosus patients

OBJECTIVE

to determine whether prolactin levels are independently associated with disease damage in systemic lupus erythematosus (SLE) patients.

METHODS

these cross-sectional analyses were conducted in SLE patient members of the Almenara Lupus Cohort who were seen between January 2012 and June 2013. Disease damage was ascertained with the System Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage index (SDI). Prolactin was measured in ng/ml. The association between prolactin levels and the SDI (total and its domains) was evaluated using Spearman's correlation. Subsequently, adjusted Poisson regression models were performed to evaluate these associations.

RESULTS

160 patients were included. 147 (91.9%) were female; their median age at diagnosis was 33.4 (interquartile range (IQR): 26.0-44.3) years; their disease duration was 5.5 (IQR: 2.6-9.7) years. The median prolactin value was 16.8 (IQR: 11.8-24.5) ng/ml. After adjusting for confounders in the Poisson regression model the estimated rate ratios (RR) and 95% confidence interval (CI) for each 10 ng/ml increment of prolactin were 1.13 (95% CI 1.60-1.20, p<0.001) for the total SDI score, 1.15 (1.03-1.28, p=0.003) for the renal domain and 1.41 (1.11-1.79, p=0.003) for the cardiac/peripheral vascular domains.

CONCLUSIONS

there was a positive association between prolactin levels and the SDI (overall and its renal and cardiac/peripheral vascular domains), independently of other well-known risk factors.

A prospective population-based cohort study of lactation and cardiovascular disease mortality: the HUNT study

Background

Recent studies suggest that lactation has long-term effects on risk for cardiovascular disease in women, but the effects on cardiovascular mortality are less well known.

Method

In a Norwegian population-based prospective cohort study, we studied the association of lifetime duration of lactation with cardiovascular mortality in 21,889 women aged 30 to 85 years who attended the second Nord-Trøndelag Health Survey (HUNT2) in 1995–1997. The cohort was followed for mortality through 2010 by a linkage with the Cause of Death Registry. Adjusted hazard ratios (HR) for death from all causes and cardiovascular disease were calculated using Cox regression.

Results

During follow-up, 1,246 women died from cardiovascular disease. Parous women younger than 65 years who had never lactated had a higher cardiovascular mortality than the reference group of women who had lactated 24 months or more (HR 2.77, 95% confidence interval [CI]: 1.28, 5.99). There was some evidence of a U-shaped association, where women who reported lactating 7–12 months had a HR of 0.55 (95% CI: 0.27, 1.09). No clear associations were observed among women 65 years or older.

Conclusions

Excess cardiovascular mortality rates were observed among parous women younger than 65 years who had never lactated. These findings support the hypothesis that lactation may have long-term influences on maternal cardiovascular health.

Duration of lactation and incidence of maternal hypertension: a longitudinal cohort study

Never or curtailed lactation has been associated with an increased risk for incident hypertension, but the effect of exclusive breastfeeding is unknown. The authors conducted an observational cohort study of 55,636 parous women in the US Nurses' Health Study II. From 1991 to 2005, participants reported 8,861 cases of incident hypertension during 660,880 person-years of follow-up. Never or curtailed lactation was associated with an increased risk of incident hypertension. Compared with women who breastfed their first child for ≥12 months, women who did not breastfeed were more likely to develop hypertension (hazard ratio (HR) = 1.27, 95% confidence interval (CI): 1.18, 1.36), adjusting for family history and lifestyle covariates. Women who never breastfed were more likely to develop hypertension than women who exclusively breastfed their first child for ≥6 months (HR = 1.29, 95% CI: 1.20, 1.40). The authors found similar results for women who had never breastfed compared with those who had breastfed each child for an average of ≥12 months (HR = 1.22, 95% CI: 1.13, 1.32). In conclusion, never or curtailed lactation was associated with an increased risk of incident maternal hypertension, compared with the recommended ≥6 months of exclusive or ≥12 months of total lactation per child, in a large cohort of parous women.

Pilot study of circulating prolactin levels and endothelial function in men with hypertension

BACKGROUND

Hyperprolactinemia has been recently associated with hypertension and endothelial dysfunction in humans, confirming animal studies performed in the 1970s that showed high prolactin levels to exert positive chronotropic and vasoconstrictive effects. Whether prolactin affects endothelial function, in the absence of hyperprolactinemia, remains unknown. Considering that secretion of prolactin presents circadian rhythmicity, we tested the hypothesis that in patients with hypertension, who present diurnal variation in their endothelial function as well, prolactin levels correlate with endothelial function and/or blood pressure.

METHODS

Endothelial function, assessed by flow-mediated dilatation (FMD) and serum prolactin were examined successively at 12 PM, 9 PM, and 7 AM in 27 nonhyperprolactinemic men with newly diagnosed, untreated essential hypertension.

RESULTS

Both FMD and prolactin presented 24-h variation (P < 0.01). FMD reached its lowest values at 7 AM (2.1 ± 1.8%, mean ± s.d.); concurrently prolactin levels peaked (7.18 ng/ml, median). Across the three time points, prolactin changes inversely interacted with FMD changes (P = 0.002). Systolic and diastolic blood pressure also varied significantly but no interaction with prolactin changes was evident.

CONCLUSIONS

Diurnal fluctuations of prolactin levels are associated with decreased endothelial function that occurs early in the morning in men with hypertension, although this study did not assess causality. Additional studies are required to determine whether these responses differ from normotensive individuals.

The renin-angiotensin-aldosterone axis in patients with nontumoral [corrected] hyperprolactinemia

OBJECTIVE

In physiological conditions, renin-angiotensin-aldosterone (RAA) axis is under continuous tonic inhibition by dopamine. The aim of this study was to evaluate the relationship of nontumoural hyperprolactinemia with the activity of adrenocortical and RAA axis, before and after administration of bromocriptine.

DESIGN

Twenty women with nontumoural hyperprolactinemia and 20 healthy women matched for body mass index and age were recruited in this study. All participants were placed on fixed salt intake for 2 weeks before the experiments. The study was conducted in three phases. In phase I, the participants received an intravenous infusion of angiotensin II in three consecutive doses of 2, 4 and 6 ng/kg BW changed every 30 min. In phase II, the patients were started on bromocriptine in gradually increasing doses of 1.25, 2.5, 5, 7.5 and 10 mg/day for 10 weeks. In phase III, the protocol of phase I was repeated in the patient group. Circulating levels of cortisol, plasma renin activity (PRA), aldosterone and prolactin were assayed.

RESULTS

Baseline values of prolactin, and PRA (2.6±0.18 nM vs 0.45±0.05 nM P<0.001 and 142.2±14.4 vs 30.7±2.7 pM/h, P<0.001, respectively) but not aldosterone (P=0.081) were significantly higher in the patient group. The angiotensin infusion test induced a significantly greater response in the patient group. Administration of the dopamine agonist restored the basal levels and diminished the response to angiotensin infusion for all the parameters tested. No change in the blood pressure was recorded.

CONCLUSIONS

Our study demonstrates that in nontumoural hyperprolactinemia there is an increased reactivity of renin-angiotensin-aldosterone (RAA) axis that is almost completely restored after treatment with a dopamine agonist.