[Biomarkers for the diagnosis and management of heart failure: natriuretic peptides]. / Biomarcatori per la diagnosi e la gestione dello scompenso cardiaco: i peptidi natriuretici.

Heart failure (HF) is the final common pathway of many cardiovascular diseases and is associated with increased morbidity and mortality. Natural history of HF patients can be improved when early diagnosis is achieved, and a timely treatment is initiated. Circulating biomarkers, reflecting pathophysiological pathways involved in HF development and progression, help clinicians diagnose and manage patients with HF. Natriuretic peptides are cardioprotective hormones released by cardiomyocytes in response to pressure/volume overload. B-type natriuretic peptides, namely B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, have been widely validated as tools for diagnosis and risk stratification of HF, and their use appears promising also for screening the population at risk and as a guide for preventive measures halting progression towards HF. Conversely, there is conflicting evidence regarding their role as a guidance for HF therapy.

Traditional and new candidate cardiac biomarkers assessed before, early, and late after half marathon in trained subjects.

PURPOSE: Cardiac Troponins (cTnI, cTnT), NT-proBNP, and galectin-3 (GAL-3) mirror cardiomyocyte injury, stretch, and fibrosis. However, although these biomarkers has been thoroughly studied in marathon or ultramarathon, the effects occurring running shorter distances, as half-marathon, are less known and data are generally limited to immediately post-race evaluation. Moreover, significant variation of alpha-1 antitrypsin (AAT), an anti-protease factor with anti-inflammatory properties, has been recently observed in heart failure, but not investigated in paraphysiological settings. The aim of the study was to evaluate these biomarkers concentration and trends in trained runners before half-marathon run and during a 48-h recovery period. METHODS: In 18 half-marathon runners (15 males, 46 ± 6 years), cTnI, GAL-3 (Architect, Abbott), cTnT, NT-proBNP (Cobas e411, Roche), and AAT (Abcam, Cambridge, UK) were evaluated at rest, immediately post-run, and at 24 and 48-h recovery period. RESULTS: cTnT, NT-proBNP, and GAL-3 transiently increased after post-race, but normalized at 24 h (GAL-3 p < 0.01, cTnT < 0.001) or 48 h (NT-proBNP < 0.001), while cTnI and AAT did not significantly change. The frequency of values exceeding the diagnostic threshold, as evaluated at baseline and after the race, did not differ for cTnI ([Formula: see text] = 1.1, p = ns), and NT-proBNP ([Formula: see text] = 6, p = ns), but significantly increased for cTnT ([Formula: see text] = 23, p < 0.001) and GAL-3 ([Formula: see text] = 6.3, p < 0.05). None of the subjects showed AAT values exceeding the reference range at baseline and at any of the time points after the race. CONCLUSION: The transient cTnT, NT-proBNP, and GAL-3 increase may suggest a temporary stress on the myocyte. However, being the increase of all biomarkers moderate and reversible, it may represent a physiological response to acute exercise.

Significance of the ionized calcium measurement to assess calcium status in osteopenic/osteoporosis postmenopausal outpatients.

INTRODUCTION: Evaluation of calcium status is important in the osteoporotic risk assessment. Although guidelines indicate total calcium (tCa) as first-line measurement, directly measured ionized calcium (m-iCa), considered as the gold standard, is more and more often required. Aim of this study is to evaluate the agreement between m-iCa, tCa and iCa calculated from a formula based on total calcium and albumin (c-iCa) in osteopenic/osteoporotic postmenopausal outpatients. METHODS: A total of 140 postmenopausal outpatients, 41 osteopenic (OPN) and 99 osteoporotic (OP) were enrolled. Levels of tCa, m-iCa, c-iCa, total protein and albumin, vitamin D (25-OHD), parathyroid hormone 1-84 (PTH), bone alkaline phosphatase, osteocalcin and serum collagen type 1 cross-linked C-telopeptide (CTX) were also measured. RESULTS: There were no statistically significant differences between OPN and OP groups regarding values of tCa, m-iCa, and c-iCa, 25-OHD and PTH. However, OP women had lower levels of CTX (p < 0.05). A significant direct correlation between m-iCa and tCa (r = 0.60, p < 0.001) and c-iCa (r = 0.61, p < 0.001) was found. Women with isolated hyper-m-iCa had similar DEXA parameter levels respect to the other patients. However, one patient with confirmed primary hyperparathyroidism presented hyper-m-iCa versus normal tCa and c-iCa values. CONCLUSIONS: The use of tCa could be sufficient to characterize the calcium status in postmenopausal outpatients, but reflexive calcium testing strategy for m-iCa test is necessary to women presenting the low or high extremes of tCa levels, or in women with suspected PHPT.

Mid-regional-pro-adrenomedullin plasma levels are increased in obese adolescents.

PURPOSE: Recently, adrenomedullin (ADM) was defined as a new member of the adipokine family. ADM secreted by adipocytes, through its vasodilator and antioxidant actions, might be protective against metabolic syndrome-associated cardiovascular complications. The aim of the study was to assess plasma mid-regional (MR)-proADM levels in obese adolescents compared to normal-weight subjects and its relation with BMI, body composition and metabolic indices. METHODS: Plasma MR-proADM was measured in 32 healthy adolescents [BMI z-score (mean ± SEM) = 0.6 ± 0.09 and 0.8 ± 0.07 in females and males, respectively] and in 51 age-matched obese adolescents [BMI z-score (mean ± SEM) = 2.8 ± 0.12 and 2.9 ± 0.08 in female and males, respectively] by a time-resolved amplified cryptate emission technology assay. RESULTS: Plasma MR-proADM levels resulted significantly higher in obese than in normal-weight adolescents (MR-proADM: 0.33 ± 0.1 vs 0.40 ± 0.1 nmol/L, p < 0.0001). Using univariate analysis, we observed that MR-proADM correlated significantly with BMI z-score (p < 0.0001), fat mass (p < 0.0001), circulating insulin (p < 0.004), HOMA-IR (p < 0.005), total cholesterol (p < 0.03) and LDL-cholesterol (p < 0.05). Including MR-proADM as response variable and its significant correlates into a multiple regression analysis, we observed that fat mass (p = 0.014) and BMI z-score (p = 0.036) were independent determinants of circulating MR-proADM. CONCLUSIONS: Our study shows for the first time that obese adolescents have higher circulating levels of MR-proADM compared with normal-weight, appropriate controls suggesting its important involvement in obese patients.

Independent effects of circulating glucose, insulin and NEFA on cardiac triacylglycerol accumulation and myocardial insulin resistance in a swine model.

AIMS/HYPOTHESIS: Cardiac steatosis and myocardial insulin resistance elevate the risk of cardiac complications in obesity and diabetes. We aimed to disentangle the effects of circulating glucose, insulin and NEFA on myocardial triacylglycerol (TG) content and myocardial glucose uptake. METHODS: Twenty-two pigs were stratified according to four protocols: low NEFA + low insulin (nicotinic acid), high NEFA + low insulin (fasting) and high insulin + low NEFA ± high glucose (hyperinsulinaemia-hyperglycaemia or hyperinsulinaemia-euglycaemia). Positron emission tomography, [U-(13)C]palmitate enrichment techniques and tissue biopsies were used to assess myocardial metabolism. Heart rate and rate-pressure product (RPP) were monitored. RESULTS: Myocardial glucose extraction was increased by NEFA suppression and was similar in the hyperinsulinaemia-hypergylcaemia, hyperinsulinaemia-euglycaemia and nicotinic acid groups. Hyperglycaemia enhanced myocardial glucose uptake due to a mass action. Myocardial TG content was greatest in the fasting group, whereas hyperinsulinaemia had a mild effect. Heart rate and RPP increased in hyperinsulinaemia-euglycaemia, in which cardiac glycogen content was reduced. Heart rate correlated with myocardial TG and glycogen content. CONCLUSIONS/INTERPRETATION: Elevated NEFA levels represent a powerful, self-sufficient promoter of cardiac TG accumulation and are a downregulator of myocardial glucose uptake, indicating that the focus of treatment should be to 'normalise' adipose tissue function to lower the risk of cardiac TG accumulation and myocardial insulin resistance. The observation that hyperinsulinaemia and nicotinic acid led to myocardial fuel deprivation provides a potential explanation for the cardiovascular outcomes reported in recent intensive glucose-lowering and NEFA-lowering clinical trials.

Maternal and sex dependency of insulin resistance: longitudinal PET and echocardiography study from the healthy fetus to the adult minipig.

UNLABELLED: Cardiovascular and metabolic vulnerability have an early developmental origin. We evaluated the potential influence of innate life factors, including the metabolism of the mother and the sex of the offspring, on cardiometabolic risk, including organ-specific insulin resistance, subclinical cardiac dysfunction, and DNA oxidative damage throughout the lifespan. METHODS: Two female minipigs were studied during late pregnancy, and their offspring were restudied at the ages of 1 mo (n = 11), 6 mo (n = 9), and 9 mo (n = 10, 6 offspring and 4 age-matched animals). We measured insulin-mediated glucose disposal in skeletal muscle, adipose tissue, liver, and myocardium using (18)F-FDG PET; cardiac function using 2-dimensional strain echocardiography; and DNA damage using the comet assay. RESULTS: Glucose metabolism showed the 2 sows to have differences similar to those in their respective 1-mo-old offspring. Over time, compared with female animals, male animals developed myocardial insulin resistance (male animals vs. female animals: 34 ± 5 vs. 58 ± 8 µmol/min/kg at 6 mo, P = 0.03; 29 ± 8 vs. 60 ± 7 µmol/min/kg at 9 mo, P = 0.02). Cardiac function progressively deteriorated in male animals from 1 mo (radial strain, -60% ± 7%; strain rate, -5.4 ± 0.9 s(-1)) to 6 mo (radial strain, -41% ± 5%; strain rate, -2.5 ± 0.2 s(-1), P < 0.05 vs. 1 mo) and 9 mo (radial strain, -32% ± 5%; strain rate, -1.6 ± 0.2 s(-1), P < 0.01 vs. 1 mo) and was significantly different from that in female animals (radial strain, -48% ± 4%; strain rate, -3.1 ± 0.2 s(-1), P < 0.05 and P < 0.01, respectively). Oxidative damage was reduced in female animals and increased in male animals across age categories (P < 0.05). CONCLUSION: The metabolism of minipig offspring is influenced by maternal insulin sensitivity during early life stages. Sex-related effects prevail thereafter in healthy minipigs, documenting a precocious onset of cardiometabolic vulnerability in male offspring.

A dose-response elevation in hepatic glucose uptake is paralleled by liver triglyceride synthesis and release.

BACKGROUND AND AIMS: Enhanced release of triglycerides (TG) by the liver is implicated in the pathogenesis of the metabolic syndrome. The aim of the study was to evaluate whether a primary elevation in hepatic glucose utilization (HGU), as induced by an acute rise in circulating glucose values during physiological hyperinsulinemia, promotes TG synthesis in spite of the reduction in free fatty acids (FFA) levels. METHODS: Glucose dose-response studies were conducted in anesthetized pigs using positron emission tomography (PET) to quantify HGU during fasting euglycemic conditions (EF), and under two-step hyperglycemic hyperinsulinemia (1st-HH +3.0, 2nd-HH +6.0 mmol/L over EF glucose values). Liver biopsies were obtained in three animals to evaluate the relationship between glucose exposure and hepatic fat content. RESULTS: Plasma glucose levels were progressively increased in the two-step studies, and otherwise stable within every hour of PET scanning. HGU increased almost fivefold with raising glucose levels, from 0.033 ± 0.009 in EF to 0.149 ± 0.043 in 1st-HH, p = 0.02, and to 0.138 ± 0.050 µmol/min/g in 2nd-HH, p = 0.03. Circulating TG concentrations increased by 50 and 100% in the two hyperglycemic conditions (p = 0.03 2nd-HH vs. EF), in spite of a 70% suppression in plasma FFA levels. The hepatic TG content paralleled the glucose loads. Plasma γ-glutamyl transferase (γ-GT) was increased by 17% (p < 0.05). CONCLUSIONS: A short-term elevation in circulating glucose levels within the physiological postprandial range was sufficient to increase HGU, resulting in a significant synthesis and release of TG by the liver, which was accompanied by an acute rise in γ-GT and liver fat content.

Heart-type fatty acid binding protein is an early marker of myocardial damage after radiofrequency catheter ablation.

OBJECTIVES: Radiofrequency (RF) ablation of arrhythmias induces myocardial damage and release of biomarkers. This study aimed to assess the kinetics of heart-type fatty acid-binding protein (h-FABP), a cytosolic protein released after myocardial injury incurred by both atrial and ventricular RF ablation, compared to other markers of myocardial injury. DESIGN AND METHODS: h-FABP, cTnI, CK-MB(mass) and myoglobin were evaluated in 30 patients with atrial or ventricular tachyarrhythmias before, immediately after and at 3, 6 and 24h after the procedure. RESULTS: h-FABP increased immediately after the procedure in all subjects (6.6 ± 1.2 µg/L vs 2.7 ± 0.3, p<0.001) but increased significantly only in ventricular ablations. The peak of h-FABP significantly correlates with the values of time for mean power of RF application in both the entire patient cohort and in ventricular ablations. CONCLUSIONS: h-FABP may be an early parameter for monitoring RF-induced lesions and the site of ablation was relevant for biomarker increase.

[Role of biomarkers in the detection of sub-clinical myocardial injury: H-FABP and radiofrequency ablation of ventricular arrhythmias]. / Utilità dei biomarcatori nella valutazione del danno cardiaco subclinico: H-FABP e ablazione in radiofrequenza delle aritmie ventricolari.

The importance of biomarker assay such as cardiac troponins and H-FABP is assuming a pivotal role not only in the diagnosis and follow-up of patients with acute coronary syndromes. Radiofrequency (RF) ablation represents a widely used method for the non pharmacologic treatment of arrhythmias.We report a case of a patient complaining of life-threatening arrhythmias treated by RF in whom temporal changes of cardiac biomarkers was determined after the procedure.

Circulating levels of lectin-like oxidized low-density lipoprotein receptor-1 are associated with inflammatory markers.

Lectin-like oxidized-low-density lipoprotein receptor-1 (LOX-1) is increasingly linked to atherosclerotic plaque formation and the soluble form of this receptor may reflect activities of disease. We investigated the associations among levels of sLOX-1, oxidized-low-density lipoprotein (ox-LDL), cytokines and the extension of atherosclerosis in patients with coronary artery disease (CAD). Lipid, TNF-alpha, IL-6, C reactive protein (CRP), ox-LDL, peroxy radical and sLOX-1 levels were measured in 29 controls and 60 patients with CAD, 30 of which with one or two vessels involved (group 1), and 30 patients with three or four vessels involved (group 2). The serum levels of sLOX-1 were significantly and progressively higher in group 1 [611 (346-1,313) pg/ml, median (interquartile range)] and in group 2 [2,143 (824-3,201) pg/ml] than in control subjects [268 (111-767) pg/ml]. LOX-1 levels positively correlated with IL-6 (r = 0.38, P = 0.0042), TNF-alpha (r = 0.38, P = 0.0037), CRP levels (r = 0.32, P = 0.027) and age (r = 0.25, P = 0.048). In the multivariate analysis TNF-alpha resulted the only independent determinant of LOX-1 serum levels (beta-value = 0.304, P = 0.017). These findings suggest that sLOX-1 levels are up-regulated during CAD progression and are associated with inflammatory markers. The measurement of the circulating soluble form of this receptor may be potentially useful in predicting CAD progression in humans.

Automation and validation of a fast method for the assessment of in vivo oxidative stress levels.

BACKGROUND: The d-ROMs test for the evaluation of serum hydroperoxides (HP) is simple, reliable, and cheap. Furthermore, it can easily be adapted to automated analyzers. Changing from the manual to an automated procedure allows the simultaneous processing of a large number of samples in a greatly reduced time, avoiding manual handling of samples and reagents and reducing variability sources. METHODS: This study was performed to adjust the manual procedure to a routine automated method in the clinical laboratory. We carried out the d-ROMs test in sera from 90 subjects of both sexes (34 men and 56 women) with age ranging from 20 to 80 years (mean 51+/-14 years). All subjects were free from acute or chronic inflammatory disease, immunological disease and history or evidence of malignancy. Subjects were not on vitamin and/or antioxidant therapies. RESULTS: The detection limit of the assay was 40 AU. Linearity was observed up to 475 AU. The recovery ranged between 97% and 105%. Within- and between-run imprecision was <5%. The mean HP value was 304+/-8 AU, with no significant difference between men (291+/-10 AU) and women (311+/-11 AU). A significant positive correlation was observed between age and HP in the whole population (r=0.4, p=0.0002). CONCLUSIONS: The automated test for the estimation of serum hydroperoxides represents a reliable and feasible procedure for increasing efficiency and reducing costs compared to the manual method, and is particularly suitable for evaluating oxidative stress in a variety of clinical conditions.

Elevated hydroperoxide levels as a prognostic predictor of mortality in a cohort of patients with cardiovascular disease.

The aim of this study was to evaluate whether hydroperoxide levels, an index of oxidative stress, predict cardiac and total death in patients with cardiovascular disease. Serum hydroperoxide levels were measured in 157 consecutive inpatients, followed during a mean follow-up of 20+/-0.3 months. Elevated oxidative stress resulted in an independent predictors for cardiac death, suggesting that hydroperoxide evaluation could provide an adjunctive estimate in the evaluation of prognosis in the cardiovascular clinical setting.

Endogenous ouabain and acute salt loading in low-renin hypertension.

BACKGROUND: Endogenous ouabain (EO), which is structurally identical to the cardiac glycoside ouabain, has been isolated in human plasma. The substance EO has been implicated in states of volume expansion and in some types of arterial hypertension, especially as a factor of salt sensitivity of blood pressure. On the other hand, salt sensitivity has been described in low-renin hypertension. The aim of this study was to determine the response of plasma EO to acute sodium expansion in low-renin hypertension. METHODS: We performed an acute intravenous sodium load (2 L of saline in 4 h) in 13 hypertensive subjects with low renin values (<0.65 ng/mL/h). We measured EO in plasma extracts by a radioimmunoassay and compared it with other endocrine parameters including atrial natriuretic peptide (ANP), aldosterone (ALDO), cortisol (CORT), adrenocorticotropic hormone (ACTH), and plasma renin activity (PRA). RESULTS: We found that EO showed only a mild nonsignificant decrease after saline infusion (from 938.8+/-218.8 pmol/L to 781.4+/-181.4 pmol/L ouabain equivalents), whereas ALDO and PRA significantly decreased (P<.0001; P<.05 respectively). The ANP significantly increased, as a marker of effective volume expansion (P<.01). At the end of the infusion, we found that EO was positively related to ACTH levels and to ALDO changes from baseline. CONCLUSIONS: Our results do not support the hypothesis that EO is stimulated in low-renin hypertension by acute salt-volume expansion. ACTH could be a factor modulating EO secretion in this condition.