Giorgio Iervasi

Low-T3 Syndrome A Strong Prognostic Predictor of Death in Patients With Heart Disease

Background—Clinical and experimental data have suggested a potential negative impact of low-T3 state on the prognosis of cardiac diseases. The aim of the present prospective study was to assess the role of thyroid hormones in the prognosis of patient population with heart disease. Methods and Results—A total of 573 consecutive cardiac patients underwent thyroid function profile evaluation. They were divided in two subgroups: group I, 173 patients with low T3, ie, with free T3 (fT3) <3.1 pmol/L, and group II, 400 patients with normal fT3 (≥3.1 pmol/L). We considered cumulative and cardiac death events. During the 1-year follow-up, there were 25 cumulative deaths in group I and 12 in group II (14.4% versus 3%, P <0.0001); cardiac deaths were 13 in group I and 6 in group II (7.5% versus 1.5%, P =0.0006). According to the Cox model, fT3 was the most important predictor of cumulative death (hazard ratio [HR] 3.582, P <0.0001), followed by dyslipidemia (HR 2.955, P =0.023), age (HR 1.051, P <0.005), and left ventricular ejection fraction (HR 1.037, P =0.006). At the logistic multivariate analysis, fT3 was the highest independent predictor of death (HR 0.395, P =0.003). A prevalence of low fT3 levels was found in patients with NYHA class III-IV illness compared with patients with NYHA class I-II (&khgr;2 5.65, P =0.019). Conclusions—Low-T3 syndrome is a strong predictor of death in cardiac patients and might be directly implicated in the poor prognosis of cardiac patients.

Circulating levels of cardiac natriuretic peptides (ANP and BNP) measured by highly sensitive and specific immunoradiometric assays in normal subjects and in patients with different degrees of heart failure

Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels increase in patients with heart failure with the progression of clinical symptoms and with the deterioration of hemodynamics; consequently, assay methods for these peptides may be useful in the follow-up of cardiac patients. Non-competitive immunoradiometric assay (IRMA) methods for ANP or BNP do not generally require preliminary extraction and/or purification of the plasma sample, and so may be more suitable than competitive immunoradiometric assay (RIA) methods for the routinary assay of plasma peptide concentrations. We evaluated the analytical characteristics and clinical usefulness of two IRMAs for plasma ANP and BNP, to verify whether these methods may be considered suitable for the follow-up of patients with heart failure. Both methods are based on the solid-phase sandwich IRMA system, which uses two monoclonal antibodies prepared against two sterically remote epitopes of peptide molecule; the first antibody was coated on the beads solid-phase and the second was radiolabeled with 125I. Blood samples were collected from a brachial vein in ice-chilled disposable polypropylene tubes containing aprotinin and EDTA after the patient had rested for at least 20 min in the recumbent position. Plasma samples were immediately separated by centrifugation and stored at −20 C until assay. The IRMA methods showed a better sensitivity and a wider working range sensitivity (about 2 ng/l) than those of RIA methods. Moreover, the normal range found with these methods (ANP= 16.1±8.6 ng/l, 5.2±2.8 pmol/l, BNP= 8.6±8.2 ng/l, 2.5±2.4 pmol/l) was similar to that generally reported using the most accurate methods, such as the other IRMAs or RIAs, using a preliminary extraction and purification of plasma samples with chromatographic procedures. Our results obtained in patients with different degrees of heart failure indicate that plasma ANP and BNP increase with the progression of clinical symptoms (NYHA class) (ANOVA p<0.0001). Indeed, circulating levels of ANP (R=− 0.701, no.=86) and BNP (R=−0.745, no.=55) were significantly (p<0.0001) and negatively correlated with the left ventricular ejection fraction values. Furthermore, a close curvilinear regression (R= 0.960, no.= 215) was found between ANP and BNP values, because plasma BNP progressively increases more than plasma ANP in patients with different stages of heart failure. In conclusion, IRMA methods are preferable for the measurement of plasma ANP and BNP for experimental studies and routine assay because they are more practicable, sensitive and accurate than RIA procedures. Finally, BNP assay appears to be better than ANP for discriminating between normal subjects and patients with different degrees of heart failure.

Acute Effects of Triiodothyronine (T3) Replacement Therapy in Patients with Chronic Heart Failure and Low-T3 Syndrome: A Randomized, Placebo-Controlled Study

CONTEXT Low-T(3) syndrome is a predictor of poor outcome in patients with cardiac dysfunction. The study aimed to assess the short-term effects of synthetic L-T(3) replacement therapy in patients with low-T(3) syndrome and ischemic or nonischemic dilated cardiomyopathy (DC). DESIGN A total of 20 clinically stable patients with ischemic (n = 12) or nonischemic (n = 8) DC were enrolled. There were 10 patients (average age 72 yr, range 66-77; median, 25-75th percentile) who underwent 3-d synthetic L-T(3) infusion (study group); the other 10 patients (average age 68 yr, range 64-71) underwent placebo infusion (control group). Clinical examination, electrocardiography, cardiac magnetic resonance, and bio-humoral profile (free thyroid hormones, TSH, plasma renin activity, aldosterone, noradrenaline, N-terminal-pro-B-Type natriuretic peptide, and IL-6) were assessed at baseline and after 3-d synthetic L-T(3) (initial dose: 20 microg/m(2) body surface.d) or placebo infusion. RESULTS After T(3) administration, free T(3) concentrations increased until reaching a plateau at 24-48 h (3.43, 3.20-3.84 vs. 1.74, 1.62-1.93 pg/ml; P = 0.03) without side effects. Heart rate decreased significantly after T(3) infusion (63, 60-66 vs. 69, 60-76 beats per minute; P = 0.008). Plasma noradrenaline (347; 270-740 vs. 717, 413-808 pg/ml; P = 0.009), N-terminal pro-B-Type natriuretic peptide (3000, 438-4005 vs. 3940, 528-5628 pg/ml; P = 0.02), and aldosterone (175, 152-229 vs. 231, 154-324 pg/ml; P = 0.047) significantly decreased after T(3) administration. Neurohormonal profile did not change after placebo infusion in the control group. After synthetic L-T(3) administration, left-ventricular end-diastolic volume (142, 132-161 vs. 133, 114-158 ml/m(2) body surface; P = 0.02) and stroke volume (40, 34-44 vs. 35, 28-39 ml/m(2) body surface; P = 0.01) increased, whereas external and intracardiac workload did not change. CONCLUSIONS In DC patients, short-term synthetic L-T(3) replacement therapy significantly improved neuroendocrine profile and ventricular performance. These data encourage further controlled trials with more patients and longer periods of synthetic L-T(3) administration.

Clinical relevance of highly sensitive Tg assay in monitoring patients treated for differentiated thyroid cancer

Objective  Serum thyroglobulin (Tg) represents a highly specific biomarker for detecting residual thyroid tissue/recurrence/metastases after treatment for differentiated thyroid cancer (DTC). We evaluated the clinical impact of a highly sensitive Tg assay during routine follow‐up of DTC patients.

The role of thyroid hormone in the pathophysiology of heart failure: clinical evidence

Thyroid hormone (TH) has a fundamental role in cardiovascular homeostasis in both physiological and pathological conditions, influencing cardiac contractility, heart rate (HR), diastolic function and systemic vascular resistance (SVR) through genomic and non-genomic mediated effects. In heart failure (HF) the main alteration of thyroid function is referred to as “low-triiodothyronine (T3) syndrome” (LT3S) characterized by decreased total serum T3 and free T3 (fT3) with normal levels of thyroxine (T4) and thyrotropin (TSH). Even if commonly interpreted as an adaptive factor, LT3S may have potential negative effects, contributing to the progressive deterioration of cardiac function and myocardial remodeling in HF and representing a powerful predictor of mortality in HF patients. All these observations, together with the early evidence of the benefits of T3 administration in HF patients indicate that placebo-controlled prospective studies are now needed to better define the safety and prognostic effects of chronic treatment with synthetic TH in HF.

Expression of thyrotropin and thyroid hormone receptors in adipose tissue of patients with morbid obesity and/or type 2 diabetes: effects of weight loss

Objective:Increased thyroid-stimulating hormone (TSH) and FT3 levels are often found in clinically euthyroid obese individuals. Information on thyroid gene expression in human adipose tissue is scarce. The objective of this study was to measure the expression of the TSH receptor (TSHR) and the thyroid hormone receptor (TRα1) genes in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in obese individuals and to test the effect of weight loss on these genes.Study Design and Participants:This study is a prospective study involving 107 obese (body mass index (BMI)=46±8 kg m−2, 52 with type 2 diabetes or impaired glucose tolerance) and 12 lean nondiabetic participants. A total of 27 obese patients were restudied 1 year after gastric bypass surgery. Total RNA was extracted from SAT and VAT obtained at baseline from all participants, and from SAT in obese patients post surgery.Results:Circulating TSH and FT3 levels were 170 and 36%, respectively, higher in obese patients than in controls. In SAT, TSHR and TRα1 were reduced in the obese by 67 and 33%, respectively, regardless of glucose tolerance. A similar trend was found in VAT. Post surgery, a BMI decrease of 33% was associated with a decrease in TSH and FT3 levels and with a 150 and 70% increase in SAT of TSHR and TRα1, respectively.Conclusion:In both subcutaneous and visceral fat, the thyroid gene expression (especially TSHR) is reduced in obesity. The reversal of these changes with major weight loss and the reciprocal changes in plasma TSH and FT3 levels suggest a role for adipocytes in the regulation of TSH and thyroid hormones.

Stress/Rest Myocardial Perfusion Abnormalities by Gated SPECT: Still the Best Predictor of Cardiac Events in Stable Ischemic Heart Disease

The prognostic power of myocardial perfusion imaging in patients with ischemic heart disease (IHD) has been demonstrated since planar imaging. We aimed to investigate whether gated SPECT retains this value in current cardiology if compared with a complete diagnostic work-up and with more recent prognostic indicators. Methods: We selected from our database a cohort of 676 consecutive inpatients who underwent a complete diagnostic work-up that included gated SPECT and coronary arteriography for known or suspected IHD. Patients with acute myocardial infarction (MI), previous coronary artery bypass surgery, or overt hyperthyroidism and patients who were undergoing dialysis treatment were excluded. During follow-up (median, 37 mo), 24 patients died from cardiac causes and 19 experienced a nonfatal MI. Results: The following were determined to be independent predictors of event-free survival (cardiac death and nonfatal MI) in the different phases of diagnostic work-up using Cox proportional hazards regression analysis: among clinical variables, a previous MI; among laboratory examinations, serum creatinine and low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels; among electrocardiographic and echocardiographic variables, left ventricular ejection fraction; and among SPECT variables, summed rest score (SRS) and summed difference score (SDS). In addition, a score of coronary stenoses at angiography was an independent predictor. When the above predictors were tested together, SRS (P < 0.0001), SDS (P = 0.0108), and serum creatinine (P = 0.0186) and LDL and HDL cholesterol levels (P = 0.0222) were the final independent predictors of event-free survival. When gated SPECT was added to the clinical, laboratory, electrocardiographic, and echocardiographic variables, the prognostic stratification significantly improved (P < 0.05); when coronary arteriography was added to gated SPECT, prognostic stratification did not further improve (P > 0.25). If the information provided by gated SPECT was made available after clinical, laboratory, electrocardiographic, echocardiographic, and angiographic variables, the prognostic stratification still improved significantly (P < 0.05). In 492 of these patients with ascertained IHD, SRS and SDS were the final independent predictors of survival. Medical treatment and coronary revascularization did not affect the prognostic information of gated SPECT. Conclusion: Myocardial perfusion abnormalities at rest and after stress are still the best predictors of cardiac event–free survival in patients with known or suspected IHD, even when compared with an extensive diagnostic work-up.

Exercise and oxidative stress: Potential effects of antioxidant dietary strategies in sports

Free radicals are produced during aerobic cellular metabolism and have key roles as regulatory mediators in signaling processes. Oxidative stress reflects an imbalance between production of reactive oxygen species and an adequate antioxidant defense. This adverse condition may lead to cellular and tissue damage of components, and is involved in different physiopathological states, including aging, exercise, inflammatory, cardiovascular and neurodegenerative diseases, and cancer. In particular, the relationship between exercise and oxidative stress is extremely complex, depending on the mode, intensity, and duration of exercise. Regular moderate training appears beneficial for oxidative stress and health. Conversely, acute exercise leads to increased oxidative stress, although this same stimulus is necessary to allow an up-regulation in endogenous antioxidant defenses (hormesis). Supporting endogenous defenses with additional oral antioxidant supplementation may represent a suitable noninvasive tool for preventing or reducing oxidative stress during training. However, excess of exogenous antioxidants may have detrimental effects on health and performance. Whole foods, rather than capsules, contain antioxidants in natural ratios and proportions, which may act in synergy to optimize the antioxidant effect. Thus, an adequate intake of vitamins and minerals through a varied and balanced diet remains the best approach to maintain an optimal antioxidant status. Antioxidant supplementation may be warranted in particular conditions, when athletes are exposed to high oxidative stress or fail to meet dietary antioxidant requirements. Aim of this review is to discuss the evidence on the relationship between exercise and oxidative stress, and the potential effects of dietary strategies in athletes. The differences between diet and exogenous supplementation as well as available tools to estimate effectiveness of antioxidant intake are also reported. Finally, we advocate the need to adopt an individualized diet for each athlete performing a specific sport or in a specific period of training, clinically supervised with inclusion of blood analysis and physiological tests, in a comprehensive nutritional assessment.

Large needle aspiration biopsy and galectin-3 determination in selected thyroid nodules with indeterminate FNA-cytology.

Thyroid fine-needle aspiration biopsy (FNA)-cytology is widely used for the preoperative characterisation of thyroid nodules but this task is difficult for follicular lesions, which often remain undefined. We propose a strategy for improving the preoperative characterisation of selected follicular thyroid proliferations, which is based on large needle aspiration biopsy (LNAB) and galectin-3 expression analysis. Eighty-five thyroid specimens were obtained by LNAB (20-gauge needles) from thyroid nodules with indeterminate follicular FNA-cytology. Aspirated material was processed as a tissue microbiopsy to obtain cell blocks for both cyto/histo-morphological evaluation and galectin-3 expression analysis, by using a purified monoclonal antibody to galectin-3 and a biotin-free immunoperoxidase staining method. Preoperative diagnosis was compared to the final histology. LNAB and cell-block technique allow a preliminary distinction between nodules with a homogeneous microfollicular/trabecular structure, as frequently observed in tumours, and lesions with mixed normo–micro–macrofollicular architecture, as observed in goitre. Furthermore, LNAB provides optimal substrates for galectin-3 expression analysis. Among 85 cases tested, 14 galectin-3-positive cases were discovered preoperatively (11 thyroid cancers and three adenomas confirmed at the final histology), whereas galectin-3-negative cases were 71 (one carcinoma and 70 benign proliferations at the final histology). Sensitivity, specificity and diagnostic accuracy of this integrated morphologic and phenotypic diagnostic approach were 91.6, 97.2 and 95.3%, respectively. In conclusion, LNAB plus galectin-3 expression analysis when applied preoperatively to selected thyroid nodules candidate to surgery can potentially reduce unnecessary thyroid resections.

Early long-term L-T3 replacement rescues mitochondria and prevents ischemic cardiac remodelling in rats

3,5,3′‐Levo‐triiodothyronine (L‐T3) is essential for DNA transcription, mitochondrial biogenesis and respiration, but its circulating levels rapidly decrease after myocardial infarction (MI). The main aim of our study was to test whether an early and sustained normalization of L‐T3 serum levels after MI exerts myocardial protective effects through a mitochondrial preservation. Seventy‐two hours after MI induced by anterior interventricular artery ligation, rats were infused with synthetic L‐T3 (1.2 μg/kg/day) or saline over 4 weeks. Compared to saline, L‐T3 infusion restored FT3 serum levels at euthyroid state (3.0 ± 0.2 versus 4.2 ± 0.3 pg/ml), improved left ventricular (LV) ejection fraction (39.5 ± 2.5 versus 65.5 ± 6.9%), preserved LV end‐systolic wall thickening in the peri‐infarct zone (6.34 ± 3.1 versus 33.7 ± 6.21%) and reduced LV infarct‐scar size by approximately 50% (all P < 0.05). Moreover, L‐T3 significantly increased angiogenesis and cell survival and enhanced the expression of nuclear‐encoded transcription factors involved in these processes. Finally, L‐T3 significantly increased the expression of factors involved in mitochondrial DNA transcription and biogenesis, such as hypoxic inducible factor‐1α, mitochondrial transcription factor A and peroxisome proliferator activated receptor γ coactivator‐1α, in the LV peri‐infarct zone. To further explore mechanisms of L‐T3 protective effects, we exposed isolated neonatal cardiomyocytes to H2O2 and found that L‐T3 rescued mitochondrial biogenesis and function and protected against cell death via a mitoKATP dependent pathway. Early and sustained physiological restoration of circulating L‐T3 levels after MI halves infarct scar size and prevents the progression towards heart failure. This beneficial effect is likely due to enhanced capillary formation and mitochondrial protection.