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Biomedical subjects

Roberto Ferrari

Publications and source records attributed to Roberto Ferrari.

14 recordsLinked to original sources
PubMed2003

Short-term heart rate variability strongly predicts sudden cardiac death in chronic heart failure patients.

BACKGROUND: The predictive value of heart rate variability (HRV) in chronic heart failure (CHF) has never been tested in a comprehensive multivariate model using short-term laboratory recordings designed to avoid the confounding effects of respiration and behavioral factors. METHODS AND RESULTS: A multivariate survival model for the identification of sudden (presumably arrhythmic) death was developed with data from 202 consecutive patients referred between 1991 and 1995 with moderate to severe CHF (age 52+/-9 years, left ventricular ejection fraction 24+/-7%, New York Heart Association class 2.3+/-0.7; the derivation sample). Time- and frequency-domain HRV parameters obtained from an 8' recording of ECG at baseline and during controlled breathing (12 to 15 breaths/min) were challenged against clinical and functional parameters. This model was then validated in 242 consecutive patients referred between 1996 and 2001 (validation sample). In the derivation sample, sudden death was independently predicted by a model that included low-frequency power (LFP) of HRV during controlled breathing < or =13 ms2 and left ventricular end-diastolic diameter > or =77 mm (relative risk [RR] 3.7, 95% CI 1.5 to 9.3, and RR 2.6, 95% CI 1.0 to 6.3, respectively). The derivation model was also a significant predictor in the validation sample (P=0.04). In the validation sample, LFP < or =11 ms2 during controlled breathing and > or =83 ventricular premature contractions per hour on Holter monitoring were both independent predictors of sudden death (RR 3.0, 95% CI 1.2 to 7.6, and RR 3.7, 95% CI 1.5 to 9.0, respectively). CONCLUSIONS: Reduced short-term LFP during controlled breathing is a powerful predictor of sudden death in patients with CHF that is independent of many other variables. These results refine the identification of patients who may benefit from prophylactic implantation of a cardiac defibrillator.

Death, Sudden, Cardiac↗
PubMed2003

Serum from patients with acute coronary syndromes displays a proapoptotic effect on human endothelial cells: a possible link to pan-coronary syndromes.

BACKGROUND: Endothelial apoptosis of atherosclerotic lesions is a possible determinant for the stable-to-vulnerable plaque transition. Recent data support the notion that plaque activation may be a pan-coronary process, advocating the existence of circulating triggers. METHODS AND RESULTS: Serum from 40 healthy subjects (group 1) and 73 patients with stable angina (n=32; group 2) or acute coronary syndromes (n=41; group 3) was incubated with human umbilical vein endothelial cells. The percentage of apoptosis by flow cytometry and Fas, Bax, and Bcl-2 protein expression by immunoblotting were evaluated at entry in patients and control subjects and repeated after 12 months in group 3. At baseline, apoptotic nuclei were higher in group 3 (14+/-6%) than in group 2 (3.3+/-1.8%) and group 1 (1.35+/-0.8%) (P<0.001). Fas and Bcl-2 were increased in group 3 with respect to groups 1 and 2 (P<0.01). Coincubation of group 3 serum with anti-tumor necrosis factor-alpha and anti-interleukin-6 monoclonal antibodies did not affect the human umbilical vein endothelial cell apoptotic process, whereas addition of Trolox decreased apoptosis to <50%. The percentage of apoptosis in group 3 significantly correlated to the numbers of coronary complex lesions at angiography (r=0.58, P<0.0005). In group 3, apoptosis and the Bax/Bcl-2 ratio decreased at 1 year (P<0.0001, P<0.05 respectively). CONCLUSIONS: Serum from patients with acute coronary syndromes displays a proapoptotic effect on human endothelial cells, supporting the theory of the existence of circulating triggers potentially able to activate atherosclerotic lesions.

Acute Disease↗
PubMed2003

Skeletal muscle abnormalities in rats with experimentally induced heart hypertrophy and failure.

BACKGROUND: In congestive heart failure (CHF), function and metabolism of skeletal muscles are abnormal. AIM: To evaluate whether the reduced oxidative capacity of skeletal muscles in CHF is due to impaired O(2) utilisation. METHODS: CHF was induced in rats by injecting 50 mg/Kg monocrotaline. Several animals received the same dose of monocrotaline but only compensated right ventricular hypertrophy and no sign of congestion resulted. Two age- and diet-matched groups of control animals were also studied. In soleus and extensor digitorum longus (EDL) muscles, we studied skeletal muscle blood flow, oxidative capacity and respiratory function of skinned muscle fibres. RESULTS: In CHF, we observed a decrease of muscle blood flow (statistically significant in the soleus, p < 0.05 vs. controls). In compensated rats, a similar trend in blood flow was observed. In both soleus and EDL, a significant reduction of high energy phosphate and a shift of the redox potential towards accumulation of reducing equivalents were observed. The reduction of energy charge was not correlated to the decrease of blood flow. In skinned myofibres, the ratio of O(2) utilised in the presence and in absence of ADP (an index of phoshorilating efficiency) was reduced from 8.9 +/- 1.9 to 2.7 +/- 0.2 (p < 0.001) and from 5.7 +/- 1.0 to 2.0 +/- 0.3 (p < 0.01) in soleus and EDL, respectively. Activity of the different complexes of respiratory chain was investigated by means of specific inhibitors, showing major abnormalities at the level of complex I. In fact, inhibition of VO(2) by rotenone was decreased from 83.5 +/- 3.2 to 36.4 +/- 9.6 % (p < 0.005) and from 81.8 +/- 6.1 to 38.2 +/- 7.4 % (p < 0.005) in soleus and EDL, respectively. CONCLUSIONS: In rats with CHF, abnormalities of oxidative phosphorylation of muscles occur and complex I of the respiratory chain seem to be primarily affected. The metabolic alterations of skeletal muscles in CHF may be explained, at least in part, by an impaired O(2) utilisation.

Animals↗
PubMed2003

Species-specific modulation of the nitric oxide pathway after acute experimentally induced endotoxemia.

OBJECTIVE: The derangement of the nitric oxide pathway is an important contributing factor to the pathogenesis of septic shock. The aim of this study was to investigate potential differences in modulation of such a pathway in two experimental models of endotoxemia. DESIGN: Prospective, randomized, placebo-controlled animal investigation. SETTING: Cardiovascular research laboratory. SUBJECTS: Male, anesthetized, and mechanically ventilated New-Zealand rabbits (n = 24) and Sprague-Dawley rats (n = 24). INTERVENTIONS: After pretreatment with 1400W (1 mg kg(-1) subcutaneously), an inhibitor of inducible nitric oxide synthase, animals received an intravenous bolus of Escherichia Coli lipopolysaccharides (5 mg kg(-1)). After 4 hrs, lungs, myocardial left ventricles, and aortas were collected. MEASUREMENTS AND MAIN RESULTS: Blood mean arterial pressure, pH, and nitrite/nitrate were monitored. Nitric oxide in the exhaled air was measured by chemiluminescence. Tissue activity of both constitutive nitric oxide synthase and inducible nitric oxide synthase was determined by measuring the conversion of [3H]L-arginine to [3H]L-citrulline. In lipopolysaccharide-treated animals, both mean arterial pressure (after 60 to 90 mins) and blood pH (after 4 hrs) decreased with respect to baseline values. 1400W prevented lipopolysaccharide-induced hypotension only in rats (p <.01). Exhaled nitric oxide decreased in lipopolysaccharide-treated rabbits by 120 mins (from 12.6 +/- 0.6 to 8.4 +/- 0.6 ppb, p <.01) and remained low until the end of the experiment (p <.01 vs. baseline). Conversely, exhaled nitric oxide increased in lipopolysaccharide-treated rats by 120 mins (from 0.4 +/- 0.1 to 5.3 +/- 1.7 ppb, p <.01) and reached a plateau by 210 mins (19.8 +/- 3.1 ppb, p <.01 vs. baseline). 1400W prevented the lipopolysaccharide-induced increase in exhaled nitric oxide and blood nitrite/nitrate in rats (p <.05). Inducible nitric oxide synthase activity increased in endotoxemic rabbit heart (0.19 +/- 0.05 vs. 0.07 +/- 0.02 pmol L-citrulline/min/mg protein in the control group, p <.05) and in all rat tissues, being more striking in the lungs (25.00 +/- 0.01 vs. 0.19 +/- 0.04 pmol L-citrulline/min/mg protein in the control group, p <.001). CONCLUSIONS: The nitric oxide pathway is differently modulated between endotoxemic rabbits and rats.

Amidines↗
PubMed2002

Urocortin promotes hemodynamic and bioenergetic recovery and improves cell survival in the isolated rat heart exposed to ischemia/reperfusion.

OBJECTIVES: This study evaluates the hemodynamic, bioenergetic and cytoprotective effects of urocortin (Ucn) in the isolated rat heart exposed to ischemia (I)/reperfusion (R). BACKGROUND: We have previously demonstrated that administration of exogenous Ucn reduces infarct size in ischemic-reperfused rat hearts. METHODS: Urocortin 10(-8)M was added to the perfusate before I, before I and during R, and during R alone in the isolated pulsed rat heart exposed to 35 min I followed by 60 min R. RESULTS: Partial to complete recovery of diastolic pressure and developed pressure was seen irrespective of when Ucn was perfused. In particular, beneficial effects are observed when Ucn is only given during R. Urocortin given only before I, and before I and over R, although not during R alone, also produces significant recovery of high-energy phosphate pools. In each group, improvement in ventricular function is associated with reduction both in myocardial damage, assessed by creatine phosphokinase release, and in endothelial cell and cardiomyocyte apoptosis, assessed by caspase 3 activity and fluorescent-based terminal deoxynucleotidyl transferase mediated nick end labelling enhanced with counterstains. These improvements in ventricular performance, bioenergetics and cell survival are not secondary to any inotropic effects of Ucn. CONCLUSIONS: This is the first report to show enhanced cardiac function induced by Ucn during I/R. Because the cytoprotective and functional benefits are still produced when Ucn is given only at R, these data suggest that Ucn may be useful clinically in the management of myocardial infarction.

Adenosine Triphosphate↗
PubMed2002

Cellular thiols redox status: a switch for NF-kappaB activation during myocardial post-ischaemic reperfusion.

Myocardial ischaemia/reperfusion induces NF-kappaB activation, but little is known about the stimuli through which it occurs. Aims of the study were to investigate whether: (a) oxidative stress induced by ischaemia/reperfusion is linked with NF-kappaB activation; (b) counteraction of oxidative stress by N-acetyl cysteine (NAC) reduces NF-kappaB activation. At this purpose, in isolated rat hearts, we induced mild (15 min) and severe (30 min) ischaemia; a group of the hearts submitted to severe ischaemia were treated with NAC. Our data indicate that reperfusion after severe ischaemia activates NF-kappaB: the presence of p65 in the nuclear extracts was 274.5+/-18.6% vs aerobia; (P<0.05) and an induced DNA-binding activity was detected. NF-kappaB translocation occurs in parallel with myocardial decrease in reduced glutathione and protein -SH (from 9.2+/-0.4 to 5.4+/-0.3 nmol/mg prot, P<0.01, and from 350.3+/-16.6 to 296.0+/-9.1 nmol/mg prot, P<0.05) and accumulation of oxidised glutathione-GSSG-(from 0.075+/-0.005 to 0.118+/-0.007 nmol/mg prot, P<0.01). When ischaemia/reperfusion does not result in any oxidative stress (in mild ischaemia or severe ischaemia plus NAC), NF-kappaB does not translocate. A significant correlation was found between the activation of NF-kappaB and the accumulation of GSSG in the myocardium. Our data indicate that an oxidative shift of cellular thiolic pools can modulate the genic transcription of the heart through NF-kappaB activation.

Animals↗
PubMed2002

Metabolic approaches to the treatment of ischemic heart disease: the clinicians' perspective.

This review article discusses pharmacological approaches to optimizing myocardial metabolism during ischemia. Fatty acids are the main fuel for the healthy heart, with a lesser contribution coming from the oxidation of glucose and lactate. Myocardial ischaemia dramatically alters fuel metabolism, causing an accelerated rate of glucose conversion to lactate and a switch from lactate uptake by the heart to lactate production. This causes a dramatic disruption in cell homeostasis (e.g. lactate accumulation and a decrease in pH and ATP). Paradoxically, moderately ischemic tissue (approximately 50% of normal flow) continues to derive most of its energy (50-70%) from the oxidation of fatty acids despite a high rate of lactate production. This ischaemia-induced disruption in cardiac metabolism can be minimized by metabolic agents that reduce fatty acid oxidation and increase the combustion of glucose and lactate, resulting in clinical benefit to the ischemic patient. Agents that inhibit fatty acid beta-oxidation, such as ranolazine and trimetazidine, have proven to be effective in the treatment of stable angina. Treatment of acute myocardial infarction patients with an infusion of the glucose-insulin-potassium, which results in suppression of myocardial fatty acid oxidation and greater glucose combustion, has proven effective in reducing mortality. These metabolic therapies are free of direct hemodynamic or chronotropic effects, and thus are well positioned for use alongside traditional agents such as beta-adrenergic receptor antagonists or calcium channel antagonists.

Humans↗
PubMed2002

Pathophysiologic and therapeutic importance of tissue ACE: a consensus report.

Angiotensin-converting enzyme (ACE) activation and the de novo production of angiotensin II contribute to cardiovascular disease through direct pathological tissue effects, including vascular remodeling and inflammation, as well as indirect action on nitric oxide bioavailability and its consequences. The endothelium plays a pivotal role in both vascular function and structure; thus, the predominant localization of ACE to the endothelium has implications for the pathobiology of vascular disease, such as coronary artery disease. Numerous experimental studies and clinical trials support the emerging realization that tissue ACE is a vital therapeutic target, and that its inhibition may restore endothelial function or prevent endothelial dysfunction. These effects exceed those attributable to blood pressure reduction alone; hence, ACE inhibitors may exert an important part of their effects through direct tissue action. Pharmacologic studies show that while ACE inhibitors may differ according to their binding affinity for tissue ACE the clinical significance remains to be determined.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2002

Future strategies of reverse remodeling prevention of hibernation.

A complex interrelationship exists among chronic ischemic left ventricular dysfunction, persistence of myocardial viability and possibility to limit progression of chronic heart failure. Cardiac remodeling is influenced by several factors still under investigation. Hibernation is basically an adaptive mechanism to chronically abnormal coronary blood flow, characterized by metabolic and structural alterations of the cardiac tissue, that are fully recovered upon revascularization. The estimate of the prevalence of myocardial viability in patients with chronic ischemic left ventricular dysfunction is crucial and different figures can be obtained by applying different diagnostic techniques and analyzing different cohorts of patients. In patients with chronic heart failure and substantial areas of myocardial ischemia and viability, revascularization is likely to prolong survival. The amount of viable myocardium needed to be clinically relevant remains to be established: only randomized prospective studies, focusing on both functional improvement and prognosis, will give an evidence-based conclusion. An aggressive and thoughtful surgical approach to patients with ischemic heart failure can yield satisfying long-term results, with survival rates superior to medical management alone, and can constitute a true and valid alternative to heart transplantation.

Heart Failure↗
PubMed2002

[Echocardiography with reconstructed M-mode: technical aspects and clinical applications].

Reconstructed M-mode imaging is a new post-processing technique that permits the reconstruction of any cardiac structure and flow from cine-loops of different sources (tissue, color Doppler and tissue Doppler cine-loops) in M-mode format. This technique can be useful in a number of clinical situations and can facilitate the echocardiographic examination, allowing for correct and easy M-mode analysis to be performed at any time, both at the patient's bedside as well as off-line. In this paper the fundamental technical features and current clinical applications of reconstructed M-mode imaging are illustrated and discussed.

Arrhythmias, Cardiac↗
PubMed2002

[Refractory heart failure. Antagonism of tumor necrosis factor alpha and endothelin in humans: 2 promises still to be honored].

Excessive biohumoral activation participates in the pathophysiology and progression of congestive heart failure (CHF). Pharmacological inhibition of the renin-angiotensin-aldosterone and beta-adrenergic systems improves the mortality and morbidity of this disease. Among other detrimental molecules, two local factors, tumor necrosis factor (TNF)-alpha and endothelin (ET) both contribute to the worsening of CHF. TNF-alpha can induce many of the cellular modifications typically associated with CHF, such as myocyte death, interstitial tissue derangement and negative inotropism. On the other hand ET promotes vasoconstriction, and cell growth and proliferation. On the premise of some favorable experimental studies, selective antagonism of TNF-alpha or ET has been tested in clinical trials in order to control the progression of or even reverse CHF. However, contrasting results have been obtained so far with either approach, in accordance with other unfavorable data from animal models of heart failure. Etanercept (Enbrel, a recombinant dimer of two p75sTNFR molecules fused to the Fc fragment of human IgG1) has proved to be useful and effective in basic and animal experiments, while contrasting data have been reported on humans. The Randomized EtaNErcept Worldwide evALuation (RENEWAL) trial has recently been prematurely stopped due to impossibility of showing statistically significant results with the pre-specified sample size. Results of phase II to III clinical trials on different ET receptor antagonists in CHF have yielded conflicting results, so that none of the agents of this class have been labeled for CHF. The mechanisms by which TNF-alpha and ET might exert their negative biological actions are discussed together with an analysis of the possible reasons why they have failed so far in human CHF.

Animals↗
PubMed2002

[Quality system Vision 2000].

A recent document of the Italian Ministry of Health points out that all structures which provide services to the National Health System should implement a Quality System according to the ISO 9000 standards. Vision 2000 is the new version of the ISO standard. Vision 2000 is less bureaucratic than the old version. The specific requests of the Vision 2000 are: a) to identify, to monitor and to analyze the processes of the structure, b) to measure the results of the processes so as to ensure that they are effective, d) to implement actions necessary to achieve the planned results and the continual improvement of these processes, e) to identify customer requests and to measure customer satisfaction. Specific attention should be also dedicated to the competence and training of the personnel involved in the processes. The principles of the Vision 2000 agree with the principles of total quality management. The present article illustrates the Vision 2000 standard and provides practical examples of the implementation of this standard in cardiological departments.

Italy↗