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.

The Obesity-Impulsivity Axis: Potential Metabolic Interventions in Chronic Psychiatric Patients

Pathological impulsivity is encountered in a broad range of psychiatric conditions and is thought to be a risk factor for aggression directed against oneself or others. Recently, a strong association was found between impulsivity and obesity which may explain the high prevalence of metabolic disorders in individuals with mental illness even in the absence of exposure to psychotropic drugs. As the overlapping neurobiology of impulsivity and obesity is being unraveled, the question asked louder and louder is whether they should be treated concomitantly. The treatment of obesity and metabolic dysregulations in chronic psychiatric patients is currently underutilized and often initiated late, making correction more difficult to achieve. Addressing obesity and metabolic dysfunction in a preventive manner may not only lower morbidity and mortality but also the excessive impulsivity, decreasing the risk for aggression. In this review, we take a look beyond psychopharmacological interventions and discuss dietary and physical therapy approaches.

Insulin sensitivity and its relation to hormones in adolescent boys and girls

BACKGROUND AND AIMS

A subset of obese individuals lacks cardiometabolic impairment. We aimed to analyze hormonal profiles of insulin-sensitive obese (ISO) and insulin-resistant obese (IRO) adolescents and determine hormonal predictors of homeostasis model of insulin resistance (HOMA-IR).

MATERIALS AND METHODS

A threshold of 3.16 of HOMA-IR was used to classify ISO (<3.16) IRO (≥3.16). In 702 individuals aged 13-18years (55.8% girls) anthropometric and laboratory [blood glucose, insulin, thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), sex hormone-binding globulin (SHBG), steroid hormones, luteinizing hormone, follicle stimulating hormone, prolactin, ghrelin, glucose-dependent insulinotropic polypeptide, glucagon-like-peptide 1glucagon, leptin, resistin, visfatin, leptin, adiponectin and adipsin] assessments were performed. Orthogonal projections to latent structures and Mann-Whitney tests with Bonferroni correction were applied for statistical analysis.

RESULTS

52.6% girls and 42.9% boys were insulin sensitive. In the predictive model of HOMA-IR thyroid function tests, adiponectin, ghrelin and leptin concentrations played an important role in both genders. Prolactin, testosterone and glucagon contributed to the model only in boys, while progesterone and dehydroepiandrosterone sulfate levels only in girls. After Bonferroni correction levels of leptin, adiponectin, leptin/adiponectin ratio, SHBG and fT4/TSH ratio in both genders, testosterone and glucagon levels in boys and levels of TSH and fT3 in girls were related to insulin sensitivity.

CONCLUSION

Metabolic health defined by HOMA-IR is partly predicted by various hormones. Some of them are gender specific. Free T4/TSH and leptin/adiponectin ratios are related to insulin sensitivity in both genders.

Prolactin levels are associated with a pro-inflammatory body mass distribution among women with systemic lupus erythematosus

Objectives The objective of this study was to determine whether prolactin levels are associated with a pro-inflammatory body mass distribution in women with systemic lupus erythematosus (SLE). Methods This cross-sectional study was conducted in consecutive female SLE patients seen in our rheumatology department from January 2012 to July 2015. Prolactin was measured in ng/ml. Body mass distribution was measured by dual energy x-ray absorptiometry and it was divided into subtotal (whole body excluding the head), subtotal bone mineral content, lean mass index (appendicular lean mass/height²), subtotal trunk and leg fat percentages and trunk-to-leg fat ratio. The association between prolactin levels and body mass distribution components was evaluated by univariable and multivariable linear regression models adjusting for possible confounders. Results One hundred and eighty-five patients were evaluated; their mean (SD) age at diagnosis was 34.8 (13.8) years; nearly all patients were Mestizo. Patients included in this study were comparable to the rest of the cohort in terms of age, disease duration, SLEDAI, SDI and body mass index. Disease duration was 7.3 (6.6) years. The SLEDAI was 5.2 (4.3) and the SDI 0.9 (1.3). Prolactin levels were 18.9 (16.7) ng/ml. In univariable analyses, prolactin was negatively associated with bone mineral density, bone mineral content, leg fat percentage and lean mass index, and positively associated with trunk-to-leg fat ratio. In the multivariable analyses, prolactin was negatively associated with bone mineral content and positively associated with trunk-to-leg fat ratio. Conclusions Higher prolactin levels are associated with a pro-inflammatory body mass distribution in SLE patients.

Association of PCSK9 with platelet reactivity in patients with acute coronary syndrome treated with prasugrel or ticagrelor: The PCSK9-REACT study

BACKGROUND

Circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) enzyme might be associated with increased activation of platelets. We aimed to assess the relationship between PCSK9 levels, platelet reactivity and ischemic outcomes.

METHODS

Consecutive ACS patients receiving prasugrel or ticagrelor and undergoing percutaneous coronary intervention (PCI) were enrolled in a prospective, observational study. Adenosine diphosphate (ADP)-induced platelet aggregation was determined by Multiplate Analyzer in the maintenance phase of treatment with prasugrel or ticagrelor. Major adverse cardiovascular events (MACEs) defined as composite of cardiovascular death, myocardial infarction, unstable angina, stent thrombosis, repeat revascularization, ischemic stroke were evaluated at 12months.

RESULTS

A direct association was found between increased PCSK9 serum levels and platelet reactivity (r=0.30; p=0.004). When assessed according to tertile values of PCSK9, there was a significant increase in platelet reactivity in the upper vs lower tertile (p=0.02). Clinical outcome was available at follow-up in 178 subjects. In the upper PCSK9 tertile 13/59 (22.03%) patients experienced a clinical MACE at one year, vs 2/59 (3.39%) patients in the lower PCSK9 tertile. At one-year follow-up, PCSK9 was independently associated with increased ischemic MACEs: hazard ratio for upper vs lower PCSK9-level tertile was 2.62 (95% confidence interval 1.24-5.52; p=0.01).

CONCLUSIONS

These findings suggest that increased PCSK9 levels are associated with higher platelet reactivity and are a possible predictor of ischemic events in ACS patients undergoing PCI.

Prolactin concentrations in antipsychotic-naïve patients with schizophrenia and related disorders: A meta-analysis

OBJECTIVE

The use of dopaminergic antagonist antipsychotics is associated with hyperprolactinemia, but some studies have found increased prolactin concentrations in antipsychotic-naive patients with schizophrenia and related disorders. We conducted a systematic review and meta-analysis of studies of prolactin in antipsychotic-naïve patient with these disorders (PRISMA No. CRD42015016337).

DATA SOURCES

PubMed (Medline), PsycInfo, and Web of Science were searched for articles from 1950 to the present in English.

STUDY SELECTION

Seven studies of males (N=141 for patients, N=191 for control subjects) and five studies of females (N=67 and N=116) met criteria for inclusion: data on blood prolactin concentrations for both control subjects and antipsychotic-naive patients with schizophrenia or a related disorder, with data available separately for males and females.

DATA EXTRACTION

Data was extracted from the papers by one author and independently verified by a second.

RESULTS

The mean effect size for males was 1.02 (95% CI, 0.77, 1.26; p<0.001) and 0.43 for females (95% CI 0.11, 0.76; p<0.01). Meta-regression analyses for age, smoking, body mass index (BMI), year of publication, and cortisol were not significant. Funnel plots did not suggest the presence of a publication bias.

CONCLUSIONS

Our meta-analyses found significantly increased prolactin levels in both male and female antipsychotic-naïve patients with schizophrenia and related disorders. The small number of studies and limited matching for potentially confounding variables in some of the studies were limitations of this analysis. Prolonged hyperprolactinemia may lead to sexual dysfunction and osteoporosis, and some antipsychotics cause additional elevation of prolactin concentrations.

Dopamine-prolactin pathway potentially contributes to the schizophrenia and type 2 diabetes comorbidity

Schizophrenia (SCZ) and type 2 diabetes (T2D) are clinically associated, and common knowledge attributes this association to side effects of antipsychotic treatment. However, even drug-naive patients with SCZ are at increased risk for T2D. Dopamine dysfunction has a central role in SCZ. It is well-known that dopamine constitutively inhibits prolactin (PRL) secretion via the dopamine receptor 2 (DR2D). If dopamine is increased or if dopamine receptors hyperfunction, PRL may be reduced. During the first SCZ episode, low PRL levels are associated with worse symptoms. PRL is essential in human and social bonding, as well as it is implicated in glucose homeostasis. Dopamine dysfunction, beyond contributing to SCZ symptoms, may lead to altered appetite and T2D. To our knowledge, there are no studies of the genetics of the SCZ-T2D comorbidity focusing jointly on the dopamine and PRL pathway in the attempt to capture molecular heterogeneity correlated to possible disease manifestation heterogeneity. In this dopamine-PRL pathway-focused-hypothesis-driven review on the association of SCZ with T2D, we report a specific revision of what it is known about PRL and dopamine in relation to what we theorize is one of the missing links between the two disorders. We suggest that new studies are necessary to establish the genetic role of PRL and dopamine pathway in SCZ-T2D comorbidity.

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.

A review of dopamine agonist therapy in type 2 diabetes and effects on cardio-metabolic parameters

Dopamine action appears to play a role in changes that are seen in obesity, metabolic syndrome and type 2 diabetes mellitus. Bromocriptine-QR (Quick Release), a dopamine agonist, is approved for use in treatment of type 2 diabetes. It has demonstrated modest improvement in glycemic parameters, cholesterol and weight in certain cohorts. Limited data using cabergoline, a long-acting dopamine agonist, also demonstrate glycemic efficacy. Additionally, bromocriptine-QR appears to have a favorable cardiovascular risk reduction. The direct mechanism by which bromocriptine-QR, or central dopamine agonism, achieves modest glycemic control and favorable cardio-metabolic profile is unclear. This relationship appears to be more complex than the historical explanation of "resetting" the circadian clock and may further be elucidated using data in individuals with hyperprolactinemia and prolactinoma.

Assessment of serum prolactin levels in acute myocardial infarction: The role of pharmacotherapy

BACKGROUND

Hyperprolactinemia may reflect neuroendocrine stress reaction against acute coronary syndromes.

AIM

The aim of the present study was evaluation of the serum prolactin level in the acute myocardial infarction (MI) regarding the current pharmacotherapy in management of MI.

SETTING AND DESIGN

Cross-sectional clinical based study.

SUBJECTS AND METHODS

This cross-sectional clinical study involved all patients with acute MI in a coronary care unit, a total number of 44 patients (45% males and 55% females) with age ranged from 40 to 75 years. A full history for modifiable risk factors and current therapy with aspirin, clopidogrel and or metformin, all patients are nonsmokers. The anthropometric measurements; for estimations of body mass index (kg/m(2)), electrocardiography was obtained. Fasting blood samples were taken in the morning from all patients and the sera used for estimations of routine investigation and determination of ischemic cardiac biomarkers like cardiac troponin I (cTnI) and serum prolactin level.

RESULTS

This study shows a significant increase in the serum prolactin in acute MI as compared with the control. In acute MI serum cTnI elevation was correlated with serum prolactin increments. In metformin-treated group, there was a lowest prolactin serum level.

CONCLUSIONS

Serum prolactin level increased in acute MI, and positively correlated with cardiac troponin level and reflects underlying cardiovascular complications.

Is prolactin the missing link in adipose tissue dysfunction of polycystic ovary syndrome patients?

The aims of the study were to evaluate whether adiposity was among the determinants of circulating prolactin levels and to determine whether serum prolactin independently predicted metabolic abnormalities in patients with polycystic ovary syndrome (PCOS). A total of 322 PCOS patients with normal serum prolactin levels were recruited between January 2007 and January 2014. Anthropometric, metabolic, and hormonal parameters were measured in all of the patients. HOMA-IR was calculated as an index of insulin resistance. Serum prolactin was negatively correlated with age (p < 0.0001), all the adiposity indices [body mass index p < 0.0001; waist circumference p < 0.0001; waist-hip ratio (WHR) p < 0.0001], visceral adiposity index (VAI, p = 0.043), fasting insulinemia (p = 0.002), and HOMA-IR (p = 0.002), and was positively correlated with serum adiponectin (p = 0.034), but not with circulating androgens or serum leptin levels. Serum adiponectin, but not HOMA-IR or fasting insulinemia, was independently associated with serum prolactin after adjustment for age, leptin, and anthropometrical adiposity parameters. Of the adiposity parameters, only WHR and VAI were independent predictors of serum prolactin after adjustment for adiponectin. Circulating prolactin was also negatively correlated with fasting glycemia (only in patients with normal glucose metabolism, p = 0.037) and was inversely correlated with the presence of metabolic syndrome (p < 0.001), but this association was not maintained after adjustment for possible confounders. In PCOS patients, serum prolactin level was related to adipose tissue quantity and function, and adiponectin was a possible mediator of this relationship. Low serum prolactin levels were associated with an unfavorable metabolic profile, but this association seemed to be due to the complex interplay among prolactin, adiposity, and insulin resistance rather than to a direct metabolic effect of prolactin.

Association of sex hormones with incident 10-year cardiovascular disease and mortality in women

OBJECTIVES

The aims of this study were to ascertain whether women with high levels of serum total testosterone (TT) or low levels of sex hormone-binding globulin (SHBG) are more likely to develop cardiovascular disease (CVD), and to investigate potential associations between sex hormones and mortality (all-cause, as well as cause-specific) in the general population.

STUDY DESIGN AND MAIN OUTCOME MEASURES

Data on 2129 women with a mean age of 49.0 years were obtained from the population-based Study of Health in Pomerania over a median follow-up of 10.9 years. Associations of baseline levels of TT, SHBG, and rostenedione (ASD), and free testosterone (fT), and of the free androgen index (FAI), with follow-up CVD morbidity, as well as all-cause and CVD mortality, were analyzed using multivariable regression modeling.

RESULTS

At baseline the prevalence rate of CVD was 17.8% (378 women) and the incidence of CVD over the follow-up was 50.9 per 1000 person-years. We detected an inverse association between SHBG and baseline CVD in age-adjusted models (relative risk per standard deviation increase: 0.83; 95% confidence interval: 0.74-0.93). We did not detect any significant associations between sex hormone concentrations and incident CVD in age- and multivariable-adjusted Poisson regression models. Furthermore, none of the sex hormones (TT, SHBG, ASD, fT, FAI) were associated with all-cause mortality.

CONCLUSIONS

This population-based cohort study did not yield any consistent associations between sex hormones in women and incident CVD or mortality risk.

Metabolic characterization of adults with binge eating in the general population: the Framingham Heart Study

OBJECTIVE

To describe the metabolic profile of individuals with objective binge eating (OBE) and to evaluate whether associations between OBE and metabolic risk factors are mediated by body mass index (BMI).

METHODS

Participants from the Framingham Heart Study, Third Generation and Omni 2 cohorts (n = 3,551, 53.1% women, mean age 46.4 years) were screened for binge eating. Multivariable-adjusted regression models to examine the associations of OBE with metabolic risk factors were used.

RESULTS

The prevalence of OBE was 4.8% in women and 4.9% in men. Compared to non-binge eating, OBE was associated with higher odds of hypertension (OR 1.85, 95% CI 1.32-2.60), hypertriglyceridemia (OR 1.42, 95% CI 1.01-2.01), low HDL (OR 1.70, 95% CI 1.18-2.44), insulin resistance (OR 3.18, 95% CI 2.25-4.50) and metabolic syndrome (OR 2.75, 95% CI 1.94-3.90). Fasting glucose was 7.2 mg dl(-1) higher in those with OBE (P = 0.0001). Individuals with OBE had more visceral, subcutaneous and liver fat. Most of these associations were attenuated with adjustment for BMI, with the exception of fasting glucose.

CONCLUSIONS

Binge eating is associated with a high burden of metabolic risk factors. Much of the associated risk appears to be mediated by BMI, with the exception of fasting glucose.

Prolactin receptor antagonism uncouples lipids from atherosclerosis susceptibility

The pituitary-derived hormone prolactin has been suggested to stimulate the development of atherosclerosis and cardiovascular disease through its effects on metabolism and inflammation. In this study, we aimed to challenge the hypothesis that inhibition of prolactin function may beneficially affect atherosclerosis burden. Hereto, atherosclerosis-susceptible LDL receptor (Ldlr) knockout mice were transplanted with bone marrow from transgenic mice expressing the pure prolactin receptor antagonist Del1-9-G129R-hPRL or their non-transgenic littermates as control. Recipient mice expressing Del1-9-G129R-hPRL exhibited a decrease in plasma cholesterol levels (-29%; P<0.05) upon feeding a Western-type diet (WTD), which could be attributed to a marked decrease (-47%; P<0.01) in the amount of cholesterol esters associated with pro-atherogenic lipoproteins VLDL/LDL. By contrast, Del1-9-G129R-hPRL-expressing mice did not display any change in the susceptibility for atherosclerosis after 12 weeks of WTD feeding. Both the absolute atherosclerotic lesion size (223 ± 33 × 10(3) μm(2) for Del1-9-G129R-hPRL vs 259 ± 32 × 10(3) μm(2) for controls) and the lesional macrophage and collagen contents were not different between the two groups of bone marrow recipients. Importantly, Del1-9-G129R-hPRL exposure increased levels of circulating neutrophils (+91%; P<0.05), lymphocytes (+55%; P<0.05), and monocytes (+43%; P<0.05), resulting in a 49% higher (P<0.01) total blood leukocyte count. In conclusion, we have shown that prolactin receptor signaling inhibition uncouples the plasma atherogenic index from atherosclerosis susceptibility in Ldlr knockout mice. Despite an associated decrease in VLDL/LDL cholesterol levels, application of the prolactin receptor antagonist Del1-9-G129R-hPRL does not alter the susceptibility for initial development of atherosclerotic lesions probably due to the parallel increase in circulating leukocyte concentrations.

Serum prolactin concentrations as risk factor of metabolic syndrome or type 2 diabetes?

BACKGROUND

To investigate potential associations of serum prolactin concentration (PRL) with metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), previously observed in small and selected study samples, in a large population-based cohort.

METHODS

Data from 3,993 individuals (2,027 women) aged 20-79 years from the population-based Study of Health of Pomerania (SHIP) were used to analyse cross-sectional and longitudinal associations of PRL with MetS and T2DM risk in age- and multivariable-adjusted Poisson regression models. PRL were log-transformed and modelled as continuous (per standard deviation (SD) increase) and categorical predictor (sex-specific quartiles) variable, separately for men and woman.

RESULTS

Cross-sectional analyses showed an inverse association between low PRL concentrations and prevalent T2DM risk in men and women after multivariable-adjustment (men: Q1 vs. Q4: relative risk (RR), 1.55; 95% confidence interval (CI), 1.13 - 2.14; women: Q1 vs. Q4: RR, 1.70; 95% CI, 1.10 - 2.62). Likewise, higher PRL concentrations were associated with significantly lower T2DM risk (RR per SD increase in log-PRL: 0.83; 95% CI, 0.72 - 0.95 in men, and 0.84; 95% CI, 0.71 - 0.98 in women, respectively). An inverse association between PRL and MetS risk was not retained after multivariable adjustment. Longitudinal analyses yielded no association of PRL with incident MetS or T2DM.

CONCLUSION

The present study is the first large population-based study reporting a cross-sectional inverse association between PRL and prevalent T2DM in both genders. But the absent longitudinal associations do not support a causal role of PRL as a risk factor of incident MetS or T2DM.