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Mariann R Piano

Publications and source records attributed to Mariann R Piano.

10 recordsLinked to original sources
PubMed2006

Biphasic changes in cardiac excitation-contraction coupling early in chronic alcohol exposure.

Although the negative inotropic effects of both acute and chronic ethanol (EtOH) exposure are well known, little is known concerning the acute-to-chronic transition of such effects. In this study, our objective was to address this question by detailing the effects that acute EtOH exposure induces on cellular excitation-contraction (EC) coupling and, subsequently, comparing whether and how such changes translate to the early chronic EtOH condition in a rat model known to develop alcohol-induced cardiomyopathy. Acute EtOH exposure, as formerly reported, indeed induced dose-dependent negative inotropic changes in cellular EC coupling, manifest as reductions in cell shortening, Ca2+ transient amplitude, Ca2+ decay rate, and sarcoplasmic reticulum Ca2+ content of isolated rat ventricular cardiac myocytes. Supplementary to this, we found Ca2+ spark character not to be significantly affected by acute EtOH exposure. In contrast, the results obtained from cardiac myocytes isolated from rats fed a diet containing approximately 9% (vol/vol) EtOH for 1 mo revealed changes in these parameters reflecting positive inotropy, whereas at 3 mo, these parameters again reflected negative inotropy similar but not identical to that induced by acute EtOH exposure. No significant changes were evident at either 1- or 3-mo chronic EtOH administration in echocardiographic parameters known to be perturbed in alcoholic cardiomyopathy (ACM), thus indicating that we were examining an asymptomatic stage in chronic EtOH administration consistent with an acute-to-chronic transition phase. Continued study of such transition-phase events should provide important insight into which molecular-cellular components of EC coupling play pivotal roles in EtOH-induced disease processes, such as ACM.

Animals↗
PubMed2006

Detection of cardiac variability in the isolated rat heart.

Cardiac variability can be assessed from two perspectives: beat-to-beat performance and continuous performance during the cardiac cycle. Linear analysis techniques assess cardiac variability by measuring the physical attributes of a signal, whereas nonlinear techniques evaluate signal dynamics. This study sought to determine if recurrence quantification analysis (RQA), a nonlinear technique, could detect pharmacologically induced autonomic changes in the continuous left ventricular pressure (LVP) and electrographic (EC) signals from an isolated rat heart-a model that theoretically contains no inherent variability. LVP and EC signal data were acquired simultaneously during Langendorff perfusion of isolated rat hearts before and after the addition of acetylcholine (n = 11), norepinephrine (n = 12), or no drug (n = 12). Two-minute segments of the continuous LVP and EC signal data were analyzed by RQA. Findings showed that%recurrence,%determinism, entropy, maxline, and trend from the continuous LVP signal significantly increased in the presence of both acetylcholine and norepinephrine, although systolic LVP significantly increased only with norepinephrine. In the continuous EC signal, the RQA trend variable significantly increased in the presence of norepinephrine. These results suggest that when either the sympathetic or parasympathetic division of the autonomic nervous system overwhelms the other, the dynamics underlying cardiac variability become stationary. This study also shows that information concerning inherent variability in the isolated rat heart can be gained via RQA of the continuous cardiac signal. Although speculative, RQA may be a tool for detecting alterations in cardiac variability and evaluating signal dynamics as a nonlinear indicator of cardiac pathology.

Acetylcholine↗
PubMed2005

Sex differences in ethanol liquid diet consumption in Sprague-Dawley rats.

There are reports of sex differences in ethanol intake between different strains of male and female rats; however, ethanol consumption (via an ethanol liquid diet) and blood ethanol levels (BELs) between male and female rats of the Sprague-Dawley strain have not been studied. Therefore, the aims of this study were to examine body growth, ethanol consumption (ml/day and g.kg(-1).day(-1)), and BELs in adult male and female (n=6-8 per group; sham-operated and ovariectomized) Sprague-Dawley rats consuming different concentrations (3% to 9% volume/volume) of the Lieber-DeCarli liquid ethanol diet. Throughout the study, male rats weighed significantly more than both female groups, and ovariectomized female rats weighed more than sham female rats. Ethanol diet consumption (ml/day) was significantly greater in male rats than in female rats at higher ethanol concentrations, whereas, when the diet consumption was expressed in grams of ethanol per kilogram of body weight per day, the sham female group was shown to consume significantly more ethanol than the male group. Even though there were differences in ethanol intake, BELs were similar among the groups. The data indicate that, similar to other strains, Sprague-Dawley rats also exhibit sex differences in their pattern of body growth (weight gain) and ethanol intake; however, BELs were similar among the groups.

Alcohol Drinking↗
PubMed2003

Cardiac structure and function after short-term ethanol consumption in rats.

Using an animal model of alcoholism, we investigated whether 4 months of ethanol consumption was associated with a preclinical stage of alcoholic cardiomyopathy (ACM), as well as activation of the renin-angiotensin system and natriuretic peptides (NPs). In other forms of cardiovascular disease, the latter peptide systems have been used as markers of left ventricular (LV) remodeling and dysfunction. Rats were fed either a liquid ethanol or control diet, and serial blood samples were collected at baseline, as well as at 2 and 4 months, for plasma renin activity (PRA), angiotensin II (ANG II), atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP) levels. Serial echocardiography (echo) was performed at the same time points, and isolated heart studies were performed to assess ex vivo contractility at 4 months. In both groups at 4 months, there were significant and similar increases in end-diastolic and end-systolic echo dimensions and LV mass. At 4 months, however, a significant decrease was found in the relative wall thickness in the ethanol-fed group compared with findings for the control group. In both groups at 4 months, significant and similar time-dependent decreases were shown in BNP and ANP levels compared with baseline values. No differences were found in NP gene expression or tissue levels. In both groups at 4 months, significant and similar increases were found in ANG II levels compared with baseline values. Over time, in both groups, PRA levels were unchanged. In this study, the only cardiac structural feature characteristic of a preclinical ACM was a decrease in relative wall thickness.

Alcohol Drinking↗
PubMed2003

Neurohormone activation.

Neurohormonal activation plays a significant role in left ventricular remodeling and progression of heart failure. Treatment strategies that antagonize the RAS and sympathetic nervous system can attenuate the left ventricular remodeling process. Natriuretic peptides, specifically BNP, are a marker of left ventricular dysfunction. With the progressive increase in the incidence and prevalence of heart failure, treatment approaches must focus on the underlying cause as well as on blocking the neurohormonal activation that leads to the remodeling process.

Aldosterone↗
PubMed2002

Alcohol and heart failure.

BACKGROUND: Current heart failure (HF) guidelines note that alcohol use should be discouraged or restricted in patients with HF resulting from left ventricular systolic dysfunction. Existing knowledge is limited in the area of HF and alcohol. METHODS AND RESULTS: The purpose of this article is to review the evidence regarding the acute and long-term use of alcohol in the setting of HF. In addition, general aspects about alcohol and alcoholic beverages that are important for understanding and interpreting alcohol-related literature are reviewed and that can be used when discussing alcoholic beverage use with patients with HF. CONCLUSIONS: There is some emerging evidence that suggests light drinking (1 to 14 drinks per week) is safe and even beneficial in HF patients with ischemic left ventricular dysfunction (LVD). However, there are no effects of light drinking in HF patients with nonischemic LVD. Clinicians should reinforce the importance of evidence based pharmacologic and nonpharmacologic therapies in HF.

Alcohol Drinking↗
PubMed2002

Alcoholic cardiomyopathy: incidence, clinical characteristics, and pathophysiology.

In the United States, in both sexes and all races, long-term heavy alcohol consumption (of any beverage type) is the leading cause of a nonischemic, dilated cardiomyopathy, herein referred to as alcoholic cardiomyopathy (ACM). ACM is a specific heart muscle disease of a known cause that occurs in two stages: an asymptomatic stage and a symptomatic stage. In general, alcoholic patients consuming > 90 g of alcohol a day (approximately seven to eight standard drinks per day) for > 5 years are at risk for the development of asymptomatic ACM. Those who continue to drink may become symptomatic and develop signs and symptoms of heart failure. ACM is characterized by an increase in myocardial mass, dilation of the ventricles, and wall thinning. Changes in ventricular function may depend on the stage, in that asymptomatic ACM is associated with diastolic dysfunction, whereas systolic dysfunction is a common finding in symptomatic ACM patients. The pathophysiology of ACM is complex and may involve cell death (possibly due to apoptosis) and changes in many aspects of myocyte function. ACM remains an important cause of a dilated cardiomyopathy, and in latter stages can lead to heart failure. Alcohol abstinence, as well as the use of specific heart failure pharmacotherapies, is critical in improving ventricular function and outcomes in these patients.

Animals↗
PubMedDate not supplied

Cellular cardiomyoplasty: a new therapeutic approach for regenerating the myocardium.

One of the most promising new therapeutic techniques for the augmentation and regeneration of the myocardium is cellular cardiomyoplasty. Reports from animal and clinical investigations indicate that the transplant of different cell types, such as autologous skeletal myoblasts and adult stem cells, into injured myocardium results in the generation of new cardiac myocytes and improvement in myocardial performance. Although there is no consensus with regard to the best cell type to transplant or the extent of myocardial renewal and regeneration, the technique of cardiac cellular myoplasty may become one of the most important advancements in the treatment of cardiovascular diseases such as myocardial infarction and heart failure.

Animals↗
PubMedDate not supplied

The effects of a sliding scale diuretic titration protocol in patients with heart failure.

Patients with heart failure (HF) are often instructed to temporarily adjust their diuretic dose. This approach has become routine in some HF management programs; however, no study has specifically examined the effects of a patient-directed flexible diuretic protocol. For the purposes of this study, patients were randomized into a usual care (UC) group (n = 31) or a flexible diuretic titration (DT) group (n = 35). The DT group completed a 6-item diuretic titration protocol once a day, for 3 months. The 6-minute walk distance, plasma B-type natriuretic peptide (NT-BNP), plasma norepinephrine (NE), and quality of life (QOL) were measured at baseline and at 3 months. Hospitalizations, emergency department (ED) visits, and mortality rates were measured at 3 months. Compared to baseline, at 3 months, there was a significant increase in the DT group's 6-minute walk distance (646 +/- 60 ft vs 761 +/- 61 ft, P = .01) and total QOL score (53 +/- 5 vs 38 +/- 5, P = .001), whereas these parameters remained unchanged within the UC group. There were significantly less ED visits in the DT group compared with those in the UC group (3% vs 23%, P = .015). No differences were found between the groups in HF-related hospitalizations or mortality. Within both groups, no differences were found between baseline and 3-month NE or NT-BNP plasma values. Patients with heart failure who used a sliding scale diuretic titration protocol had significant improvements in their exercise tolerance and QOL, had fewer ED visits, and had no change in plasma NE or NT-BNP levels.

Clinical Protocols↗