Thyroid hormones have a central role in cardiovascular homeostasis. In myocardium, these hormones stimulate both diastolic myocardial relaxation and systolic myocardial contraction, have a pro-angiogenic effect and an important role in extracellular matrix maintenance. Thyroid hormones modulate cardiac mitochondrial function. Dysfunction of thyroid axis impairs myocardial bioenergetic status. Both overt and subclinical hypothyroidism are associated with a higher incidence of coronary events and an increased risk of heart failure progression. Endothelial function is also impaired in hypothyroid state, with decreased nitric oxide-mediated vascular relaxation. In heart disease, particularly in ischemic heart disease, abnormalities in thyroid hormone levels are common and are an important factor to be considered. In fact, low thyroid hormone levels should be interpreted as a cardiovascular risk factor. Regarding ischemic heart disease, during the late post-myocardial infarction period, thyroid hormones modulate left ventricular structure, function and geometry. Dysfunction of thyroid axis might even be more prevalent in the referred condition since there is an upregulation of type 3 deiodinase in myocardium, producing a state of local cardiac hypothyroidism. In this focused review, we summarize the central pathophysiological and clinical links between altered thyroid function and ischemic heart disease. Finally, we highlight the potential benefits of thyroid hormone supplementation as a therapeutic target in ischemic heart disease.
The impact of thyroid hormone dysfunction on ischemic heart disease
Madalena von Hafe, João Sergio Neves, Catarina Vale, Marta Borges-Canha, and Adelino Leite-Moreira
Heart, lipids and hormones
Peter Wolf, Yvonne Winhofer, Martin Krššák, and Michael Krebs
Cardiovascular disease is the leading cause of death in general population. Besides well-known risk factors such as hypertension, impaired glucose tolerance and dyslipidemia, growing evidence suggests that hormonal changes in various endocrine diseases also impact the cardiac morphology and function. Recent studies highlight the importance of ectopic intracellular myocardial and pericardial lipid deposition, since even slight changes of these fat depots are associated with alterations in cardiac performance. In this review, we overview the effects of hormones, including insulin, thyroid hormones, growth hormone and cortisol, on heart function, focusing on their impact on myocardial lipid metabolism, cardiac substrate utilization and ectopic lipid deposition, in order to highlight the important role of even subtle hormonal changes for heart function in various endocrine and metabolic diseases.
The kidney, subclinical thyroid disease and cardiovascular outcomes in older patients
L E Zijlstra, D M van Velzen, S Simsek, S P Mooijaart, M van Buren, D J Stott, I Ford, J W Jukema, and S Trompet
Thyroid hormones have been implicated to play a role in cardiovascular disease, along with studies linking thyroid hormone to kidney function. The aim of this study is to investigate whether kidney function modifies the association of subclinical thyroid dysfunction and the risk of cardiovascular outcomes.
In total, 5804 patients were included in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). For the current analysis, 426 were excluded because of overt thyroid disease at baseline or 6 months, 266 because of inconsistent thyroid function at baseline and 6 months, 294 because of medication use that could influence thyroid function, and 16 because of missing kidney or thyroid values. Participants with normal fT4 were classified, based on TSH both at inclusion and 6 months, into three groups: subclinical hypothyroidism (TSH >4.5 mIU/L); euthyroidism (TSH = 0.45–4.5 mIU/L); and subclinical hyperthyroidism (TSH <0.45 mIU/L). Strata of kidney function were made based on estimated glomerular filtration rate into three clinically relevant groups: <45, 45–60, and >60 mL/min/1.73 m2. The primary endpoint consists of death from coronary heart disease, non-fatal myocardial infarction and (non)fatal stroke.
Mean age was 75.3 years, and 49.0% patients were male. Mean follow-up was 3.2 years. Of all participants, 109 subjects (2.2%) had subclinical hypothyroidism, 4573 (94.0%) had euthyroidism, and 182 (3.7%) subclinical hyperthyroidism. For patients with subclinical hypothyroidism, euthyroidism, and subclinical hyperthyroidism, primary outcome occurred in 9 (8.3%), 712 (15.6%), and 23 (12.6%) patients, respectively. No statistically significant relationship was found between subclinical thyroid dysfunction and primary endpoint with adjusted hazard ratios of 0.51 (0.24–1.07) comparing subclinical hyperthyroidism and 0.90 (0.58–1.39) comparing subclinical hypothyroidism with euthyroidism. Neither was this relationship present in any of the strata of kidney function, nor did kidney function interact with subclinical thyroid dysfunction in the association with primary endpoint (P interaction = 0.602 for subclinical hyperthyroidism and 0.388 for subclinical hypothyroidism).
In this secondary analysis from PROSPER, we found no evidence that the potential association between thyroid hormones and cardiovascular disease is modified by kidney function in older patients with subclinical thyroid dysfunction.
Cardiovascular risk factors in mild adrenal autonomous cortisol secretion in a Caucasian population
Agnieszka Adamska, Vitalii Ulychnyi, Katarzyna Siewko, Anna Popławska-Kita, Małgorzata Szelachowska, Marcin Adamski, Angelika Buczyńska, and Adam Jacek Krętowski
Cardiovascular risk factors could be present in mild adrenal autonomous cortisol secretion (MACS). However, the most frequent cardiovascular risk factors in MACS have not been established. The aim of the presseent study was to analyse the difference in cardiovascular risk factors in patients with MACS in comparison to those with non-functioning adrenal tumour (NFAT). A total of 295 patients with adrenal incidentaloma were included in this retrospective study. We divided our group into those who showed suppression in 1 mg overnight dexamethasone suppression test (DST) (NFAT) (serum cortisol level ≤1.8 μg/dL) and those who did not show suppression in the DST (MACS) (serum concentration of cortisol > 1.8 μg/dL and ≤5 μg/dL). In the studied groups, we analysed the presence of cardiovascular risk factors, such as obesity, prediabetes, type 2 diabetes mellitus (T2DM), hypertension, hyperlipidaemia, chronic kidney disease and cardiovascular events. In our study, 18.9% of patients were defined as MACS. Importantly, T2DM was diagnosed in 41% of MACS vs 23% of NFAT (P < 0.01) and higher frequency of occurrence of hyperlipidaemia in NFAT (72.4%) vs MACS (53.6%) (P = 0.01) was observed. We did not observed differences in the frequency of obesity, hypertension, chronic kidney disease, prediabetes, atrial fibrillation, stroke, ST and non-ST elevation myocardial infarction and coronary angioplasty between patients with MACS and NFAT (all P > 0.05; respectively). In MACS, T2DM is more prevalent than in NFAT; hyperlipidaemia is more prevalent in NFAT. Accordingly, no differences were found in the incidence of obesity, hypertension, prediabetes, chronic kidney disease between studied groups as well as cardiovascular events.
Angiopoietin-like proteins 3, 4 and 8 are linked to cardiovascular function in naïve sub-clinical and overt hypothyroid patients receiving levothyroxine therapy
Sahar Hossam El Hini, Yehia Zakaria Mahmoud, Ahmed Abdelfadel Saedii, Sayed Shehata Mahmoud, Mohamed Ahmed Amin, Shereen Riad Mahmoud, and Ragaa Abdelshaheed Matta
Angiopoietin-like proteins (ANGPTL) 3, 4 and 8 are upcoming cardiovascular biomarkers. Experimental studies showed that thyroid hormones altered their levels. We assessed ANGPTL3, 4 and 8 as predictors of cardiovascular functions among naïve subclinical and naïve overt hypothyroidism (SCH and OH) and altered ANGPTL levels with levothyroxine replacement (LT4) and their association with improved cardiovascular risk factors and cardiovascular function.
Design and methods
The study was a prospective follow-up study that assessed ANGPTL3, 4 and 8 levels, vascular status (flow-mediated dilation% of brachial artery (FMD%), carotid intima-media thickness (CIMT), aortic stiffness index (ASI)), left ventricle (LV) parameters (ejection fraction (EF), myocardial performance index (MPI), and LV mass), well-known cardiovascular risk factors and homeostatic model for the assessment of insulin resistance, at two time points, that is, among naïve SCH, naïve OH, and healthy subjects groups; and at 6 months after achieving the euthyroid state with LT4 by calculating their increased or decreased delta changes (∆↑ or ∆↓) in longitudinal arm among LT4-hypothyroid groups.
Significantly elevated levels of ANGPTL3, 4 and 8 among hypothyroid groups than the healthy subjects were reduced with LT4. Multivariate analysis revealed ANGPTLs as independent predictors of cardiovascular functions and the contributors for ANGPTL level included ANGPTL3 and 4 for impaired FMD%, and ANGPTL8 for LV mass among naïve SCH; ANGPTL3 for EF% and ANGPTL8 for CIMT in naïve OH; ∆↓ANGPTL3 for ∆↓ASI meanwhile ∆↑freeT4 for ∆↓ANGPTL3, ∆↓fasting glucose, ∆↓triglyceride, and ∆↓thyroid peroxidase antibody for ∆↓ANGPTL4 among LT4-SCH. ∆↓ANGPTL4 for ∆↓MPI and ∆↓LV mass, meanwhile ∆↓TSH and ∆↓triglyceride for ∆↓ANGPTL3, ∆↑free T3 and ∆↓HOMA-IR for ∆↓ANGPTL4, and systolic blood pressure and waist circumference for ∆↓ANGPTL8 among LT4-OH.
Elevated ANGPTL3, 4 and 8 levels are differentially independent predictors of endothelial and cardiac function and are reduced with LT4 in SCH and OH.
Optimal LDL cholesterol levels in young and old patients with type 2 diabetes for secondary prevention of cardiovascular diseases are different
Chaiho Jeong, Bongseong Kim, Jinyoung Kim, Hansang Baek, Mee Kyoung Kim, Tae-Seo Sohn, Ki-Hyun Baek, Ki-Ho Song, Hyun-Shik Son, Kyungdo Han, and Hyuk-Sang Kwon
Real-world-based population data about the optimal low-density lipoprotein cholesterol (LDL-C) level for preventing cardiovascular disease in very high-risk populations is scarce.
From 2009 to 2012, 26,922 people aged ≥ 40 years with type 2 diabetes mellitus (T2DM) who had a history of percutaneous coronary intervention (PCI) were analyzed. Data from the Korean National Health Insurance System were used. They were followed up to the date of a cardiovascular event or the time to death, or until December 31, 2018. Endpoints were recurrent PCI, newly stroke or heart failure, cardiovascular death, and all-cause death. Participants were divided into the following categories according to LDL-C level: <55 mg/dL, 55–69 mg/dL, 70–99 mg/dL, 100–129 mg/dL, 130–159 mg/dL, and ≥ 160 mg/dL.
Compared to LDL-C < 55 mg/dL, the hazard ratios (HR) for re-PCI and stroke increased linearly with increasing LDL-C level in the population < 65 years. However, in ≥ 65 years old, HRs for re-PCI and stroke in LDL-C = 55–69 mg/dL were 0.97 (95% CI: 0.85–1.11) and 0.96 (95% CI: 0.79–2.23), respectively. The optimal range with the lowest HR for heart failure and all-cause mortality were LDL-C = 70–99 mg/dL and LDL-C = 55–69 mg/dL, respectively, in all age groups (HR: 0.99, 95% CI: 0.91–1.08 and HR: 0.91, 95% CI: 0.81–1.01).
LDL-C level below 55 mg/dL appears to be optimal in T2DM patients with established cardiovascular disease aged < 65 years, while an LDL-C level of 55–69 mg/dL may be optimal for preventing recurrent PCI and stroke in patients over 65 years old.
The STC2–PAPP-A–IGFBP4–IGF1 axis and its associations to mortality and CVD in T2D
Mette Faurholdt Gude, Rikke Hjortebjerg, Mette Bjerre, Morten Haaning Charles, Daniel R Witte, Annelli Sandbæk, and Jan Frystyk
Physiologically, pregnancy-associated plasma protein-A (PAPP-A) serves to liberate bound IGF1 by enzymatic cleavage of IGF-binding proteins (IGFBPs), IGFBP4 in particular. Clinically, PAPP-A has been linked to cardiovascular disease (CVD). Stanniocalcin-2 (STC2) is a natural inhibitor of PAPP-A enzymatic activity, but its association with CVD is unsettled. Therefore, we examined associations between the STC2–PAPP-A–IGFBP4–IGF1 axis and all-cause mortality and CVD in patients with type 2 diabetes (T2D).
We followed 1284 participants with T2D from the ADDITION trial for 5 years.
Circulating concentrations of STC2, PAPP-A, total and intact IGFBP4 and IGF1 and -2 were measured at inclusion. End-points were all-cause mortality and a composite CVD event: death from CVD, myocardial infarction, stroke, revascularisation or amputation. Survival analysis was performed by Cox proportional hazards model.
During follow-up, 179 subjects presented with an event. After multivariable adjustment, higher levels of STC2, PAPP-A, as well as intact and total IGFBP4, were associated with all-cause mortality; STC2: hazard ratio (HR) = 1.84 (1.09–3.12) (95% CI); P = 0.023, PAPP-A: HR = 2.81 (1.98–3.98); P < 0.001, intact IGFBP4: HR = 1.43 (1.11–1.85); P = 0.006 and total IGFBP4: HR = 3.06 (1.91–4.91); P < 0.001. Higher PAPP-A levels were also associated with CVD events: HR = 1.74 (1.16–2.62); P = 0.008, whereas lower IGF1 levels were associated with all-cause mortality: HR = 0.51 (0.34–0.76); P = 0.001.
This study supports that PAPP-A promotes CVD and increases mortality. However, STC2 is also associated with mortality. Given that STC2 inhibits the enzymatic effects of PAPP-A, we speculate that STC2 either serves to counteract harmful PAPP-A actions or possesses effects independently of the PAPP-A–IGF1 axis.
PAPP-A has pro-atherosclerotic effects and exerts these most likely through IGF1. IGF1 is regulated by the STC2–PAPP-A–IGFBP4–IGF1 axis, where STC2, an irreversible inhibitor of PAPP-A, has been shown to reduce the development of atherosclerotic lesions in mice. We examined the association of this axis to mortality and CVD in T2D. We demonstrated an association between PAPP-A and CVD. All components of the STC2–PAPP-A–IGFBP4–IGF1 axis were associated with mortality and it is novel that STC2 was associated with mortality in T2D. Our study supports that inhibition of PAPP-A may be a new approach to reducing mortality and CVD. Whether modification of STC2 could serve as potential intervention warrants further investigation.
Cardiac magnetic resonance imaging of myocardial mass and fibrosis in primary aldosteronism
Marianne Aa Grytaas, Kjersti Sellevåg, Hrafnkell B Thordarson, Eystein S Husebye, Kristian Løvås, and Terje H Larsen
Primary aldosteronism (PA) is associated with increased cardiovascular morbidity, presumably due to left ventricular (LV) hypertrophy and fibrosis. However, the degree of fibrosis has not been extensively studied. Cardiac magnetic resonance imaging (CMR) contrast enhancement and novel sensitive T1 mapping to estimate increased extracellular volume (ECV) are available to measure the extent of fibrosis.
To assess LV mass and fibrosis before and after treatment of PA using CMR with contrast enhancement and T1 mapping.
Fifteen patients with newly diagnosed PA (PA1) and 24 age- and sex-matched healthy subjects (HS) were studied by CMR with contrast enhancement. Repeated imaging with a new scanner with T1 mapping was performed in 14 of the PA1 and 20 of the HS median 18 months after specific PA treatment and in additional 16 newly diagnosed PA patients (PA2).
PA1 had higher baseline LV mass index than HS (69 (53–91) vs 51 (40–72) g/m2; P < 0.001), which decreased significantly after treatment (58 (40–86) g/m2; P < 0.001 vs baseline), more with adrenalectomy (n = 8; −9 g/m2; P = 0.003) than with medical treatment (n = 6; −5 g/m2; P = 0.075). No baseline difference was found in contrast enhancement between PA1 and HS. T1 mapping showed no increase in ECV as a myocardial fibrosis marker in PA. Moreover, ECV was lower in the untreated PA2 than HS 10 min post-contrast, and in both PA groups compared with HS 20 min post-contrast.
Specific treatment rapidly reduced LV mass in PA. Increased myocardial fibrosis was not found and may not represent a common clinical problem.
Aldosterone-induced cardiac damage in primary aldosteronism depends on its subtypes
Satoshi Higuchi, Hideki Ota, Yuta Tezuka, Kazumasa Seiji, Hidenobu Takagi, Jongmin Lee, Yi-Wei Lee, Kei Omata, Yoshikiyo Ono, Ryo Morimoto, Masataka Kudo, Fumitoshi Satoh, and Kei Takase
This study compared cardiac function, morphology, and tissue characteristics between two common subtypes of primary aldosteronism (PA) using a 3T MR scanner.
A retrospective, single-center, observational study.
We retrospectively reviewed 143 consecutive patients with PA, who underwent both adrenal venous sampling and cardiac magnetic resonance. We acquired cine, late gadolinium enhancement, and pre- and postcontrast myocardial T1-mapping images.
PA was diagnosed as unilateral aldosterone-producing adenoma (APA) in 70 patients and bilateral hyperaldosteronism (BHA) in 73. The APA group showed significantly higher plasma aldosterone concentration (PAC) and aldosterone to renin rate (ARR) than the BHA group. After controlling for age, sex, antihypertensive drugs, systolic and diastolic blood pressure, and disease duration, the parameters independently associated with APA were: left ventricular end-diastolic volume index (EDVI: adjusted odds ratio (aOR) = 1.06 (95% CI: 1.030–1.096), P < 0.01), end-systolic volume index (ESVI: 1.06 (1.017–1.113), P < 0.01), stroke index (SI: 1.07 (1.020–1.121), P < 0.01), cardiac index (CI: 1.001 (1.000–1.001), P < 0.01), and native T1 (1.01 (1.000–1.019), P = 0.038). Weak positive correlations were found between PAC and EDVI (R = 0.28, P < 0.01), ESVI (0.26, P < 0.01), and SI (0.18, P = 0.03); and between ARR and EDVI (0.25, P < 0.01), ESVI (0.24, P < 0.01), and native T1 (0.17, P = 0.047).
APA is associated with greater LV volumetric parameters and higher native T1 values, suggesting a higher risk of volume overload and myocardial damage.
The heart as an endocrine organ
Tsuneo Ogawa and Adolfo J de Bold
The concept of the heart as an endocrine organ arises from the observation that the atrial cardiomyocytes in the mammalian heart display a phenotype that is partly that of endocrine cells. Investigations carried out between 1971 and 1983 characterised, by virtue of its natriuretic properties, a polypeptide referred to atrial natriuretic factor (ANF). Another polypeptide isolated from brain in 1988, brain natriuretic peptide (BNP), was subsequently characterised as a second hormone produced by the mammalian heart atria. These peptides were associated with the maintenance of extracellular fluid volume and blood pressure. Later work demonstrated a plethora of other properties for ANF and BNP, now designated cardiac natriuretic peptides (cNPs). In addition to the cNPs, other polypeptide hormones are expressed in the heart that likely act upon the myocardium in a paracrine or autocrine fashion. These include the C-type natriuretic peptide, adrenomedullin, proadrenomedullin N-terminal peptide and endothelin-1. Expression and secretion of ANF and BNP are increased in various cardiovascular pathologies and their levels in blood are used in the diagnosis and prognosis of cardiovascular disease. In addition, therapeutic uses for these peptides or related substances have been found. In all, the discovery of the endocrine heart provided a shift from the classical functional paradigm of the heart that regarded this organ solely as a blood pump to one that regards this organ as self-regulating its workload humorally and that also influences the function of several other organs that control cardiovascular function.