Globulina transportadora de hormonas sexuales: nuevo marcador de severidad y pronóstico en varones con insuficiencia cardiaca crónica

Sex hormone-binding globulin and heart failure hospitalizations in patients with dysglycemia: Experiences from the outcome reduction with an Initial Glargine Intervention trial

INTRODUCTION

Sex hormone-binding globulin (SHBG), which binds most of circulating testosterone in blood, has been linked to dysglycemia and cardiovascular disease but the relationship with heart failure remains unclear.

AIM

To study the relation between SHBG and heart failure hospitalizations.

METHODS

SHBG levels were analysed in dysglycemic participants at high cardiovascular risk (n = 8401) followed for a median of 6.2 years in the Outcome Reduction with an Initial Glargine Intervention trial. Cox regression was used to estimate hazard ratios (HRs) per one standard deviation increase for heart failure hospitalizations adjusted for age, comorbidities, biochemical data (including testosterone) and pharmacological treatment.

RESULTS

5553 men and 2848 women were included. Heart failure hospitalizations occurred in 349 (6.3 %) men and 123 (4.3 %) women. One standard deviation increase in SHBG was independently associated with an increased risk of heart failure hospitalizations in men (HR 1.15, 95 % CI 1.03-1.28; p = 0.011) but not in women (HR 1.15; 95 % CI 0.96-1.39; p = 0.14).

CONCLUSIONS

In patients with dysglycemia and high cardiovascular risk, increasing SHBG was associated with greater risk of HF hospitalizations independent of testosterone concentrations in men but not in women, suggesting the effects could be mediated through androgen-independent pathways.

Genetic and environmental determinants of diastolic heart function

Diastole is the sequence of physiological events that occur in the heart during ventricular filling and principally depends on myocardial relaxation and chamber stiffness. Abnormal diastolic function is related to many cardiovascular disease processes and is predictive of health outcomes, but its genetic architecture is largely unknown. Here, we use machine learning cardiac motion analysis to measure diastolic functional traits in 39,559 participants of the UK Biobank and perform a genome-wide association study. We identified 9 significant, independent loci near genes that are associated with maintaining sarcomeric function under biomechanical stress and genes implicated in the development of cardiomyopathy. Age, sex and diabetes were independent predictors of diastolic function and we found a causal relationship between genetically-determined ventricular stiffness and incident heart failure. Our results provide insights into the genetic and environmental factors influencing diastolic function that are relevant for identifying causal relationships and potential tractable targets.

Well-Known and Novel Serum Biomarkers for Risk Stratification of Patients with Non-ischemic Dilated Cardiomyopathy

Non-ischemic dilated cardiomyopathy encompasses a wide spectrum of myocardial disorders, characterized by left ventricular dilatation with systolic impairment and increased risk of sudden cardiac death. In spite of all the therapeutic progress that has been made in recent years, dilated cardiomyopathy continues to be an important cause of cardiac transplant, being associated with an enormous cost burden for health care systems worldwide. Predicting the prognosis of patients with dilated cardiomyopathy is essential to individualize treatment. Late gadolinium enhancement-cardiac magnetic resonance imaging, microvolt T-wave alternans, and genetic testing have emerged as powerful tools in predicting sudden cardiac death occurrence and maximizing patient's selection. Despite all these new diagnostic modalities, additional tests to complement or replace current tools are required for better risk stratification. Therefore, biomarkers are an easy and important tool that can help to detect patients at risk of adverse cardiovascular events. Additionally, identifying potential biomarkers involved in dilated cardiomyopathy can provide us important information regarding the diagnostic, prognostic, risk stratification, and response to treatment for these patients. Many potential biomarkers have been studied in patients with dilated cardiomyopathy, but only a few have been adopted in current practice. Therefore, the aim of our review is to provide the clinicians with an update on the well-known and novel biomarkers that can be useful for risk stratification of patients with non-ischemic dilated cardiomyopathy.

Endocrine Challenges in Patients with Continuous-Flow Left Ventricular Assist Devices

Heart failure (HF) remains a leading cause of morbidity, hospitalization, and mortality worldwide. Advancement of mechanical circulatory support technology has led to the use of continuous-flow left ventricular assist devices (LVADs), reducing hospitalizations, and improving quality of life and outcomes in advanced HF. Recent studies have highlighted how metabolic and endocrine dysfunction may be a consequence of, or associated with, HF, and may represent a novel (still neglected) therapeutic target in the treatment of HF. On the other hand, it is not clear whether LVAD support, may impact the outcome by also improving organ perfusion as well as improving the neuro-hormonal state of the patients, reducing the endocrine dysfunction. Moreover, endocrine function is likely a major determinant of human homeostasis, and is a key issue in the recovery from critical illness. Care of the endocrine function may contribute to improving cardiac contractility, immune function, as well as infection control, and rehabilitation during and after a LVAD placement. In this review, data on endocrine challenges in patients carrying an LVAD are gathered to highlight pathophysiological states relevant to this setting of patients, and to summarize the current therapeutic suggestions in the treatment of thyroid dysfunction, and vitamin D, erythropoietin and testosterone administration.

Genetic polymorphisms of the SHBG gene can be the effect on SHBG and HDL-cholesterol levels in Coronary Heart Disease: a case-control study

Sex hormone binding globulin (SHBG) level is positively associated with the high-density lipoprotein cholesterol (HDL-C) levels. The aim of this study was to investigate the effects of the SHBG gene variations (D356N, rs1799941, and P156L) on SHBG and HDL-C levels and Coronary Heart Disease (CHD) risk. The SHBG D356 N (rs6259,G > A), P156L (rs6258,C > T), and rs1799941(G > A) polymorphisms were determined in 131 male CHD patients and 55 male controls by PCR-RFLP and real-time PCR techniques. SHGB levels were measured by Electro-chemiluminescence immunoassay (ECLIA). In the patients who had SHBG levels lower than threshold 35 nmol/l value, the risk of being HDL-C levels lower than threshold 0.90 mmol/l value was observed statistically significant (p = 0.017; OR 2.522, 95% CI 1.170-5.438). The rs1799941 GG was associated with increased CHD risk when compared with the A allele carriers (GA + AA) (p = 0.019, OR 2.222, 95% CI 1.130-4.371). In addition, the rs1799941 GG genotype and D356 N N allele were associated with lower SHBG in the CHD group (p < 0.01). The logistic regression analysis also revealed the rs1799941 GG genotype was significantly associated with low SHBG in CHD patients. It was observed that Haplotype-1(rs1799941 G allele-P156L P allele-D356 N D allele) was associated with increased CHD risk, while Haplotype-2 (rs1799941 rare A allele-P156L C allele- D356 N G allele) was correlated with the decreased CHD risk (p = 0.0167). Our findings suggest that there is a positive correlation between SHBG and HDL-C levels in CHD patients, and this association might be affected by SHBG gene variations.

Testosterone, sex hormone-binding globulin and risk of cardiovascular events: A report from the Outcome Reduction with an Initial Glargine Intervention trial

Aims: Testosterone and its binding protein sex hormone-binding globulin have been associated with cardiovascular disease and dysglycaemia. However, information on the prognostic implication in patients at high cardiovascular risk with dysglycaemia is inconsistent. The study objective was to determine whether testosterone and/or sex hormone-binding globulin predict cardiovascular events or death in dysglycaemic patients.

Methods: Dysglycaemic males at high cardiovascular risk ( n = 5553) who participated in the Outcome Reduction with an Initial Glargine Intervention (ORIGIN) trial and provided baseline blood samples were studied. Testosterone and sex hormone-binding globulin were measured at baseline and used to estimate free testosterone. Low levels of total and free testosterone were defined as ≤300 ng/dl and ≤7 ng/dl, respectively. Patients were followed for six years for cardiovascular events (defined as the composite of cardiovascular death, non-fatal myocardial infarction or stroke) and all-cause mortality.

Results: The mean total and free testosterone levels were 416.6 ng/dl and 8.4 ng/dl, and low levels were present in 13% and 37% of the patients. The median sex hormone-binding globulin level was 35 nmol/l. In Cox regression models adjusted for age, previous diseases and pharmacological treatment, neither total nor free testosterone predicted cardiovascular events. However, a one-standard-deviation increase in sex hormone-binding globulin predicted both cardiovascular events (hazard ratio 1.07; 95% confidence interval 1.00–1.14; p = 0.03) and all-cause mortality (hazard ratio 1.13; 95% confidence interval 1.06–1.21; p < 0.01).

Conclusion: Sex hormone-binding globulin, but not total testosterone, predicts cardiovascular disease and all-cause mortality in dysglycaemic males at high cardiovascular risk.

Association of sex hormone-binding globulin and free testosterone with mortality in men with type 2 diabetes mellitus

OBJECTIVE

Low circulating testosterone levels have been associated with increased mortality in men. We hypothesized that the prognostic role of testosterone in men with type 2 diabetes mellitus (T2DM) is influenced by its carrier protein sex hormone-binding globulin (SHBG).

DESIGN

We conducted a prospective cohort study at a tertiary referral centre.

METHODS

In total, 531 men with T2DM presenting to a diabetes clinic in 2004-2005 were followed prospectively until death, or July 31, 2014, and a survival analysis was performed. The main outcome measure was all cause mortality.

RESULTS

Over a mean (S.D.) follow up of 7.6 years (2.6) 175 men (33%) died. In Cox proportional hazard models both higher SHBG (Hazard Ratio (HR) 1.012 (95% CI 1.002-1.022), P=0.02) and lower calculated free testosterone (cFT) (HR 0.995 (95% CI 0.993-0.998), P=0.001) were risk factors for all cause mortality independently of age, BMI, presence of macro- and microvascular disease, duration of T2DM, hemoglobin, renal function, insulin use, C-reactive protein and homeostatic model of insulin resistance. By contrast, the inverse association of total testosterone (TT) with mortality weakened after these adjustments (P=0.11). SHBG remained associated with mortality (P<0.001) both if substituted for or added to TT in the multivariable model. In the fully adjusted model, an increase of SHBG by 17.3 nmol/l (1 S.D.) increased mortality by 22% and a decrease in cFT by 81 pmol/l (1 S.D.) increased mortality by 45%.

CONCLUSIONS

The association of SHBG with mortality in men with T2DM is novel. Whether SHBG acts via regulation of testosterone, has intrinsic biological roles, or is a marker of poor health requires further study.

Elevated serum Bisphenol A level in patients with dilated cardiomyopathy

Background: This study aimed to determine serum Bisphenol A (BPA) concentrations in patients with dilated cardiomyopathy (DCM) as well as the association between serum BPA and several hormonal parameters in DCM patients compared with a healthy control group. Materials and methods: Eighty-eight DCM patients and 88 age- and gender-matched healthy controls were included. Serum BPA levels and several hormonal parameters (including total testosterone (T), sex hormone-binding globulin (SHBG) and estradiol (E2) were measured by using corresponding ELISA Kits. The free androgen index (FAI) was calculated by the formula: total T in nmol/L × 100/SHBG in nmol/L. Results: BPA levels in the total DCM group were significantly higher compared with that in the controls (6.9 ± 2.7 ng/mL vs. 3.8 ± 1.9 ng/mL, p < 0.001). Significant difference was also observed in SHBG and FAI between DCM patients and controls, (76.9 ± 30.9 nM/L vs. 41.0 ± 15.6 nM/L and 2.9 ± 3.5 vs. 5.3 ± 2.6, respectively, both of p < 0.001). Similar trends were observed in the male and female subgroup. Mean T level was lower in DCM group than in control group (540.8 ± 186.0 pg/mL vs. 656.3 ± 112.9 pg/mL, p < 0.001). Linear regression analysis has shown that increasing serum BPA levels were statistically significantly associated with increased SHBG levels. However, no statistical difference was noted for E2. Conclusion: Our findings firstly demonstrated that BPA exposure increased in DCM patients compared with that in healthy controls, while FAI and T levels decreased. SHBG presented a positive association with BPA. It is concluded that hormone disorder induced by BPA exposure might be an environmental factor in the pathology of DCM.

Targeting oxidized LDL improves insulin sensitivity and immune cell function in obese Rhesus macaques

Oxidation of LDL (oxLDL) is a crucial step in the development of cardiovascular disease. Treatment with antibodies directed against oxLDL can reduce atherosclerosis in rodent models through unknown mechanisms. We demonstrate that through a novel mechanism of immune complex formation and Fc-γ receptor (FcγR) engagement, antibodies targeting oxLDL (MLDL1278a) are anti-inflammatory on innate immune cells via modulation of Syk, p38 MAPK phosphorylation and NFκB activity. Subsequent administration of MLDL1278a in diet-induced obese (DIO) nonhuman primates (NHP) resulted in a significant decrease in pro-inflammatory cytokines and improved overall immune cell function. Importantly, MLDL1278a treatment improved insulin sensitivity independent of body weight change. This study demonstrates a novel mechanism by which an anti-oxLDL antibody improves immune function and insulin sensitivity independent of internalization of oxLDL. This identifies MLDL1278a as a potential therapy for reducing vascular inflammation in diabetic conditions.

Circulating testosterone and estradiol, autonomic balance and baroreflex sensitivity in middle-aged and elderly men with heart failure

BACKGROUND

Heart failure (HF) is considered as a cardiogeriatric syndrome. Its fundamental pathophysiological feature is autonomic imbalance (and associated abnormalities within cardiovascular reflex control), but recent evidence suggests the involvement of deranged hormone metabolism. Both these neural and endocrine pathologies have serious clinical and prognostic consequences in patients with HF. We investigated the relations between autonomic status, baroreflex sensitivity (BRS) and hormone status in men with mild systolic HF.

METHODS

We examined 46 men with stable systolic HF (age: 62 ± 10 years, NYHA class I/II: 10/36 [22%/78%], ischemic aetiology: 72%, left ventricular ejection fraction: 32 ± 8%). Serum hormone levels (i.e. total testosterone [TT], dehydroepiandrosterone sulphate [DHEAS], oestradiol [E2], insulin-like growth factor type 1 [IGF-1] and cortisol) were assessed using immunoassays. Estimated free testosterone (eFT) was estimated using the Vermeulen's equation. Heart rate variability (HRV) was assessed in time and frequency domains, based on 10-min resting recordings. BRS was estimated using the sequence method (BRS-Seq) and the phenylephrine test (BRS-Phe).

RESULTS

Deficiencies in circulating TT, eFT, DHEAS and IGF-1 (defined as a serum hormone ≤the 10th percentile calculated for the adequate age category in the cohort of healthy men) were found in respectively 13%, 30%, 55% and 93% of men with systolic HF. Serum SHBG ≥50 nmol/L and cortisol ≥700 nmol/L characterised, respectively 44% and 29% of men with HF. In multivariable models after the adjustment for clinical variables, the following relationships were found in examined men: DHEAS and SDNN (time domain of HRV defined as a standard deviation of average R-R intervals) (β = 0.29, p = 0.03); E2 and: HRV-LF (ms(2)) (β = 0.37, p = 0.01), HRV-HF (ms2) (β = 0.44, p = 0.02) and BRS-Phe (β = 0.51, p = 0.008); TT and: HRV-HF (%) (β = 0.35, p = 0.02), HRV-LF/HF ratio (β = -0.35, p = 0.02) and BRS-Seq (β = 0.33, p = 0.04).

CONCLUSIONS

The observed associations between reduced circulating androgens, oestrogens and lower HRV and depleted BRS, irrespectively of HF severity suggest the pathophysiological links between these two mechanisms. These results constitute the premises to investigate whether the pharmacological supplementation of depleted hormones would enable to restore the autonomic balance and improve the efficacy of reflex control within the cardiovascular system in men with systolic HF.

Testosterone deficiency in male heart failure patients and its effect on endothelial progenitor cells

BACKGROUND

Endothelial progenitor cells (EPCs) are thought to contribute to reendothelialization and neoangiogenesis. Since it is known that EPCs express a testosterone receptor, we wanted to assess the prevalence of testosterone deficiency in patients with CHF and its impact on circulating EPCs.

METHODS

137 male patients with chronic heart failure (CHF) were included (age 61 ± 13 years; BMI 29 ± 5 kg/m(2); New York Heart Association classification (NYHA) I: n = 47, NYHA II: n = 51, NYHA III: n = 39). Numbers of different populations of circulating EPCs were quantified using flow cytometry. Levels of free testosterone and EPC-regulating cytokines were determined using ELISA.

RESULTS

The prevalence of testosterone deficiency in our University CHF clinic was 39%. However, there was no difference between patients with and without testosterone deficiency regarding their levels of EPCs. Testosterone levels were inversely correlated with age (R(2) = -0.32, p = 0.001) and NYHA status (R(2) = 0.28, p = 0.001) and correlated with cardiorespiratory capacity (R(2) = 0.26, p = 0.03).

CONCLUSION

Testosterone deficiency is frequent in male patients with CHF but does not appear to impact the regenerative EPCs.

Testosterone replacement therapy and cardiovascular risk factors modification

Hypogonadism in males is associated with increased atherosclerotic disease. Physiologically, testosterone appears to have both positive and negative effects on the cardiovascular system. Testosterone decreases angina and may improve the cardiac healing response after myocardial infarction. Testosterone enhances function in males with heart failure (HF). Testosterone causes water retention and oedema is common in older persons. Oedema should not be used to diagnose HF in older persons. Studies in older persons with HF and frailty have shown a non-statistically lower mortality rate compared to those receiving placebo.