Management of obesity cardiomyopathy

The effect of obesity and subsequent weight reduction on cardiac morphology and function in cats

BACKGROUND

In people, obesity is a risk factor for cardiovascular disease, associated with systemic hypertension, cardiac remodelling and systolic and diastolic dysfunction. Weight reduction can reverse myocardial remodelling and reduce risk of subsequent cardiovascular disease. In cats, far less is known regarding the effects of obesity and subsequent weight reduction on cardiovascular morphology and function. This prospective study aimed to assess cardiac morphology and function, heart rate variability, cardiac biomarkers and body composition before and after controlled weight reduction in cats with obesity. Body composition analysis (by dual energy x-ray absorptiometry, DEXA) and cardiovascular assessment (echocardiography, systemic arterial systolic blood pressure, electrocardiography, plasma cardiac biomarkers) were performed prior to weight management in twenty cats with obesity. These investigations were repeated in eleven cats that reached target weight.

RESULTS

At baseline, systemic hypertension was not documented, but the majority of cats with obesity (15 out of 19) showed echocardiographic evidence of diastolic dysfunction. Eleven of 20 cats had increased maximal end-diastolic septal or left ventricular free wall thickness (≥ 6.0 mm) at baseline. Median (interquartile range) percentage of weight lost in the cats reaching target weight was 26% (17-29%), with a median reduction in body fat mass of 45% (26-64%). Both the end-diastolic left ventricular free wall (median magnitude of change -0.85 mm, IQR -0.05 mm to -1.55 mm, P = 0.019; median percentage reduction 14.0%) and end-diastolic interventricular septum (median magnitude of change -0.5 mm, IQR -0.2 mm to -1.225 mm, P = 0.047; median percentage reduction 7.9%) thickness decreased after weight reduction. Following weight reduction, pulsed wave tissue Doppler imaging of the left ventricular free wall was consistent with improved diastolic function in 4 out of 8 cats, however there was no significant difference in overall diastolic function class. Further, there was no change in heart rate variability or cardiac biomarkers with weight reduction.

CONCLUSION

An increase in left ventricular wall thickness and diastolic dysfunction were common echocardiographic features in cats with obesity within our study and may be reversible with successful weight and fat mass loss. Further studies are required to clarify the clinical consequences of these findings.

Toll-like receptor 2 deficiency ameliorates obesity-induced cardiomyopathy via inhibiting NF-κB signaling pathway

Growing evidence demonstrates that chronic low-grade inflammation, which is induced by high-fat diet (HFD) or saturated fatty acid, plays an important role in the obesity-induced cardiomyopathy (OIC) process. Moreover, obesity is associated with the activation of different inflammatory pathways, including nuclear factor-κB (NF-κB), Toll-like-receptor-2 (TLR2) and Toll-like-receptor-4 (TLR4). In this study, we established an HFD-induced cardiac injury mouse model and palmitate (PA)-induced myocardial cell model to evaluate the role of TLR2 in OIC. Our data show that TLR2 blockade using TLR2 knockout (KO) mice or a TLR2-specific inhibitor, C29, markedly ameliorated HFD- or PA-induced inflammation, myocardial fibrosis, and hypertrophy both in vivo and in vitro. Moreover, the PA-induced myocardial cell injury was mediated via inducing the formation of TLR2-MyD88 complex in a TLR4-independent manner in cardiomyocytes. Our data prove the critical role of cardiac TLR2 in the pathogenesis of HFD- and saturated fatty acid-induced myocarditis, fibrosis, myocardial hypertrophy, and cardiac dysfunction. Inhibition of TLR2 pathway may be a therapeutic strategy of OIC.

The effect of obesity and subsequent weight reduction on cardiac structure and function in dogs

Background

In people, the cardiovascular effects of obesity include systemic hypertension, cardiac remodelling and both systolic and diastolic dysfunction, whilst weight reduction can reverse myocardial remodelling and reduce risk of subsequent cardiovascular disease. To date, variable results are reported in studies of the effect of obesity and controlled weight reduction on cardiovascular morphology and function in dogs. This prospective study aimed to assess cardiac function, heart rate variability, cardiac biomarkers and body composition before and after weight reduction in pet dogs with obesity. Twenty-four client-owned dogs referred for weight management due to obesity were recruited. To assess the cardiac effects of obesity, body composition analysis (by dual energy X-ray absorptiometry, DEXA) and cardiovascular assessment (echocardiography, Doppler blood pressure, electrocardiography, cardiac biomarkers) were performed prior to weight management. Twelve dogs completed the study and reached target weight, receiving a further cardiovascular assessment and DEXA. A Wilcoxon-signed rank test was used to compare each variable pre- and post- weight reduction.

Results

Median (interquartile range) duration of weight loss was 224 days (124–245 days), percentage weight loss was 23% (18–31%) of starting weight. Median change in body fat mass was -50% (-44% to -55%; P = 0.004), whilst median change in lean mass was -7% (+ 1% to -18%, P = 0.083).

Before weight reduction, diastolic dysfunction (evidence of impaired relaxation in all dogs), increased left ventricular wall thickness and mildly elevated systolic blood pressure (14/24 ≥ 160 mmHg, median 165 mmHg (140–183)) were common features in dogs with obesity. However, systolic left ventricular wall dimensions were the only variables that changed after weight reduction, with a decrease in both the systolic interventricular septum (P = 0.029) and systolic left ventricular free wall (P = 0.017). There was no evidence of decreased heart rate variability in dogs with obesity (P = 0.367), and no change in cardiac biomarker concentrations with weight reduction (N-terminal proBNP, P = 0.262; cardiac troponin I P = 0.657).

Conclusions

Canine obesity results in diastolic dysfunction and left ventricular hypertrophy, the latter of which improves with significant weight and fat mass reduction. Further studies are required to clarify the clinical consequences of these findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03449-4.

Epigenetics and obesity cardiomyopathy: From pathophysiology to prevention and management

Uncorrected obesity has been associated with cardiac hypertrophy and contractile dysfunction. Several mechanisms for this cardiomyopathy have been identified, including oxidative stress, autophagy, adrenergic and renin-angiotensin aldosterone overflow. Another process that may regulate effects of obesity is epigenetics, which refers to the heritable alterations in gene expression or cellular phenotype that are not encoded on the DNA sequence. Advances in epigenome profiling have greatly improved the understanding of the epigenome in obesity, where environmental exposures during early life result in an increased health risk later on in life. Several mechanisms, including histone modification, DNA methylation and non-coding RNAs, have been reported in obesity and can cause transcriptional suppression or activation, depending on the location within the gene, contributing to obesity-induced complications. Through epigenetic modifications, the fetus may be prone to detrimental insults, leading to cardiac sequelae later in life. Important links between epigenetics and obesity include nutrition, exercise, adiposity, inflammation, insulin sensitivity and hepatic steatosis. Genome-wide studies have identified altered DNA methylation patterns in pancreatic islets, skeletal muscle and adipose tissues from obese subjects compared with non-obese controls. In addition, aging and intrauterine environment are associated with differential DNA methylation. Given the intense research on the molecular mechanisms of the etiology of obesity and its complications, this review will provide insights into the current understanding of epigenetics and pharmacological and non-pharmacological (such as exercise) interventions targeting epigenetics as they relate to treatment of obesity and its complications. Particular focus will be on DNA methylation, histone modification and non-coding RNAs.

Reversible Cardiomyopathies

Cardiomyopathies (CMs) have many etiological factors that can result in severe structural and functional dysregulation. Fortunately, there are several potentially reversible CMs that are known to improve when the root etiological factor is addressed. In this article, we discuss several of these reversible CMs, including tachycardia-induced, peripartum, inflammatory, hyperthyroidism, Takotsubo, and chronic illness-induced CMs. Our discussion also includes a review on their respective pathophysiology, as well as possible management solutions.

Management of obesity cardiomyopathy

Obesity causes a variety of hemodynamic alterations that may lead to changes in cardiac structure and function. Although such abnormalities may occur in patients with mild-to-moderate obesity, they are most pronounced in those with morbid obesity. When these alterations produce congestive heart failure, obesity cardiomyopathy is said to be present. In this review, the authors will first discuss the pathogenesis and clinical manifestations of obesity cardiomyopathy and then describe the management of this clinical syndrome with emphasis on the effects of weight reduction.

Cardiac ryanodine receptor in metabolic syndrome: is JTV519 (K201) future therapy?

Metabolic syndrome is characterized by a combination of obesity, hypertension, insulin resistance, dyslipidemia, and impaired glucose tolerance. This multifaceted syndrome is often accompanied by a hyperdynamic circulatory state characterized by increased blood pressure, total blood volume, cardiac output, and metabolic tissue demand. Experimental, epidemiological, and clinical studies have demonstrated that patients with metabolic syndrome have significantly elevated cardiovascular morbidity and mortality rates. One of the main and frequent complications seen in metabolic syndrome is cardiovascular disease. The primary endpoints of cardiometabolic risk are coronary and peripheral arterial disease, myocardial infarction, congestive heart failure, arrhythmia, and stroke. Alterations in expression and/or functioning of several key proteins involved in regulating and maintaining ionic homeostasis can cause cardiac disturbances. One such group of proteins is known as ryanodine receptors (intracellular calcium release channels), which are the major channels through which Ca(2+) ions leave the sarcoplasmic reticulum, leading to cardiac muscle contraction. The economic cost of metabolic syndrome and its associated complications has a significant effect on health care budgets. Improvements in body weight, blood lipid profile, and hyperglycemia can reduce cardiometabolic risk. However, constant hyperadrenergic stimulation still contributes to the burden of disease. Normalization of the hyperdynamic circulatory state with conventional therapies is the most reasonable therapeutic strategy to date. JTV519 (K201) is a newly developed 1,4-benzothiazepine drug with antiarrhythmic and cardioprotective properties. It appears to be very effective in not only preventing but also in reversing the characteristic myocardial changes and preventing lethal arrhythmias. It is also a unique candidate to improve diastolic heart failure in metabolic syndrome.

Cardiac β-adrenoceptor expression is markedly depressed in Ossabaw swine model of cardiometabolic risk

Ossabaw swine have a “thrifty genotype” and consumption of excess calories induces many classical components of the metabolic syndrome, including obesity, insulin resistance, impaired glucose tolerance, dyslipidemia, hyperleptinemia, and hypertension. Earlier studies indicate that the metabolic syndrome is associated with diminished cardiac function; however, to what degree this impairment is associated with alterations in myocardial β₁- and β₂-adrenoceptor (AR) expression has not been fully elucidated. Accordingly, the present study was designed to investigate the effects of the metabolic syndrome on cardiac β₁- and β₂-AR expression. Studies were conducted on left ventricular tissue samples obtained from control lean and chronically (50 weeks) high-fat-fed obese animals. Chronic feeding significantly increased fasting plasma insulin, total cholesterol, triglycerides, blood glucose, systolic and diastolic blood pressure, and heart rate. Real-time polymerase chain reaction revealed no significant alterations in cardiac β₁- and β₂-AR mRNA expression. In contrast, Western blot analysis revealed a significant decrease in ventricular β₁- and β₂-AR protein expression. This is the first report in a novel large animal model that induction of metabolic syndrome is accompanied by a significant reduction in cardiac β₁- and β₂-AR protein expression that could contribute to impaired cardiac function.

Effects of weight loss on the cardiac parameters of obese dogs

Obesity is one of the most frequent nutritional problems in companion animals and can lead to severe health problems in dogs and cats, such as cardiovascular diseases. This research aimed to evaluate the structural and functional cardiac changes after weight loss in obese dogs. Eighteen obese healthy dogs were assigned into three different groups, according with their initial body weight: Group I (dogs up to 15 kg), Group II (dogs weighing between 15.1 and 30 kg), and Group III (dogs weighing over 30 kg). The animals were submitted to a caloric restriction weight-loss program until they lose 15% of the body weight. The M-mode echocardiogram, electrocardiogram, and blood pressure evaluations were performed before the diet has started and after the dogs have reached the target weight. Data showed a decrease in left ventricular free wall thickness during diastole and systole in Group III, decrease in the systolic blood pressure in Group III, and also in the mean blood pressure in Group II. It was possible to conclude that the weight loss program can reverse structural cardiac changes such as left ventricle eccentric hypertrophy in dogs weighing more than 30 kg, and decrease the arterial blood pressure in obese dogs.

How 40 kilograms of fluid retention can be overlooked: two case reports

INTRODUCTION

With a rising incidence of severe obesity in developed nations, heart failure, a well-recognised co-morbidity, is becoming more common.

CASE PRESENTATION

We describe two recent patients encountered, a 64 year old and a 42 year old, who are both severely obese and presented with fluid retention of approximately 40 kilograms. Assessment revealed that the explanation of the gross clinical features were relatively subtle cardiac abnormalities. These cases illustrate how fluid retention in severe obesity can differ from that seen in 'traditional' heart failure in terms of clinical assessment and management.

CONCLUSION

Severe obesity can result in insidious fluid retention, which can be easily overlooked until large volumes of fluid have accumulated. Cardiac abnormalities are usually found in these patients, but may be relatively subtle, leading to current debate in the definition and classification of heart failure. These scenarios are increasingly being encountered in clinical practice. Recognition, assessment and treatment of the 'clinical syndrome of heart failure' in severe obesity is often difficult.

The effects of obesity and non-pharmacological weight loss on vascular and ventricular function and structure

AIMS

The mechanisms by which obesity confers increased cardiovascular risk and the effects of moderate weight loss on cardiovascular health are incompletely understood. We sought to characterize the preclinical changes in cardiac and vascular health that accompany obesity and the influence of lifestyle modification on these parameters.

METHODS

Preclinical markers of vasculopathy in resistance vessels and conduit arteries and left ventricular structure and function were assessed in 39 obese subjects (BMI > 30 kg/m(2)) and 11 healthy weight controls. The influence of serum on cellular adhesion molecule (CAM) expression on human endothelial cells was studied ex vivo in a subgroup of 13 obese and nine healthy weight subjects. These analyses were repeated in all 17 of the obese subjects who complied with 4-9 months of lifestyle modification treatment (six with weight loss >5% and 11 with weight loss <5%).

RESULTS

Compared with healthy weight controls, obese subjects had decreased peak hyperaemic forearm blood flow (p = 0.015), increased carotid intima-media thickness (p = 0.009), increased left ventricular wall thickness and volume and evidence of systolic and diastolic dysfunction as assessed using tissue Doppler imaging (S', p = 0.09; E'/A', p = 0.02), and serum from obese subjects increased the intercellular CAM-1 expression on human endothelial cells (p = 0.009). However, arterial endothelial function assessed by flow-mediated dilatation was not altered (p = 0.99). Lifestyle modification treatment resulted in potentially beneficial changes in fibrinogen (p = 0.003), HDL cholesterol (p = 0.05) and soluble vascular CAM-1 (p = 0.06). In subjects with weight loss greater than 5% of body weight, there was also a decrease in low-level inflammation (high-sensitivity C-reactive protein, p = 0.05), lipid peroxidation (thiobarbituric acid-reactive substances, p = 0.05) and triglycerides (p = 0.07).

CONCLUSIONS

Obesity is associated with widespread alterations in cardiac and vascular structure and function. Moderate short-term weight loss by lifestyle modification results in some beneficial changes in serum profile; however, these are not accompanied by significant alterations to either cardiac or vascular structure and function.

Canadian Cardiovascular Society Consensus Conference guidelines on heart failure--2008 update: best practices for the transition of care of heart failure patients, and the recognition, investigation and treatment of cardiomyopathies

Heart failure is a clinical syndrome that normally requires health care to be provided by both specialists and nonspecialists. This is advantageous because patients benefit from complementary skill sets and experience, but can present challenges in the development of a common, shared treatment plan. The Canadian Cardiovascular Society published a comprehensive set of recommendations on the diagnosis and management of heart failure in January 2006, and on the prevention, management during intercurrent illness or acute decompensation, and use of biomarkers in January 2007. The present update builds on those core recommendations. Based on feedback obtained through a national program of heart failure workshops during 2006 and 2007, several topics were identified as priorities because of the challenges they pose to health care professionals. New evidence-based recommendations were developed using the structured approach for the review and assessment of evidence that was adopted and previously described by the Society. Specific recommendations and practical tips were written for best practices during the transition of care of heart failure patients, and the recognition, investigation and treatment of some specific cardiomyopathies. Specific clinical questions that are addressed include: What information should a referring physician provide for a specialist consultation? What instructions should a consultant provide to the referring physician? What processes should be in place to ensure that the expectations and needs of each physician are met? When a cardiomyopathy is suspected, how can it be recognized, how should it be investigated and diagnosed, how should it be treated, when should the patient be referred, and what special tests are available to assist in the diagnosis and treatment? The goals of the present update are to translate best evidence into practice, apply clinical wisdom where evidence for specific strategies is weaker, and aid physicians and other health care providers to optimally treat heart failure patients, resulting in a measurable impact on patient health and clinical outcomes in Canada.

Cardiac Surgery in Patients With Body Mass Index of 50 or Greater

BACKGROUND

The seemingly inexorable rise in obesity worldwide is creating a new set of challenges for healthcare providers. Demand for cardiac surgical intervention among patients at extreme levels of obesity (body mass index [BMI] > or = 50) is increasing; however, the risks, benefits, and resources required to meet this need have not been established.

METHODS

Between 1993 and 2004, 57 patients with a BMI of 50 or more underwent cardiac surgical procedures at our institution. The mean BMI was 54 +/- 4, weight range was 124 to 226 kg. The mean age of the study group was 55 +/- 12 years, and comorbidities included diabetes mellitus in 29 (51%), hypertension in 40 (70%), hyperlipidemia in 22 (39%), and obstructive sleep apnea in 16 (28%).

RESULTS

The operative mortality was 7% (4 patients). Eleven patients (20%) required prolonged intubation (more than 24 hours), and mean intensive care unit stay was 5 +/- 9 days. Wound complications requiring surgery occurred in 3 (5%). Survival at 1 and 5 years was 93% +/- 4% and 76 +/- 8%, respectively. By univariate analysis, age and endocarditis were associated with long-term mortality and major perioperative complications. As a dichotomous variable, BMI greater than 54 was a significant predictor of renal failure and prolonged mechanical ventilation.

CONCLUSIONS

Cardiac surgery in the patient with a BMI of 50 or greater is associated with significant resource utilization, including prolonged intensive care unit and hospital stay, with prolonged intubation and wound complications relatively common.

Effect of Orlistat in obese patients with heart failure: a pilot study

Heart failure is the leading cause of hospitalization. Obesity is increasingly common and is a major public health problem. The aim of this study is to assess whether obese patients with heart failure can benefit from losing weight via an orlistat-assisted diet. This randomized clinical trial included obese patients with ejection fractions < or =40%. Orlistat and diet counseling were compared with diet counseling alone. Twenty-one consecutive obese patients with heart failure were recruited. Significant improvement in 6-minute walk test (45.8 m; 95% confidence interval, 5.2-86.4 m; p=0.031), functional class (-0.6+/-0.5, p=0.014), weight loss (-8.55 kg; 95% confidence interval, -13.0 to -4.1 kg; p<0.001) and also significant decreases in total cholesterol (p=0.017), low-density lipoprotein cholesterol (p=0.03), and triglycerides (p=0.036) were observed in the orlistat group. Orlistat can promote significant weight loss and symptoms of relief in obese patients with heart failure, as measured by 6-minute walk test and functional capacity. The lipid profile improved. Orlistat was safe and well tolerated.

Effects of weight loss after gastric bypass on right and left ventricular function assessed by tissue Doppler imaging

To evaluate the effects of substantial weight loss on tissue Doppler imaging parameters of right ventricular (RV) and left ventricular (LV) systolic and diastolic function, we performed standard echocardiography and tissue Doppler imaging in 17 patients with severe obesity before and after gastric bypass. Patients lost 39 +/- 10 kg over 7.6 +/- 3.6 months. Adjusted LV mass decreased (134 +/- 41 to 119 +/- 31 kg/m, p = 0.031). After weight loss, the ratios of early-to-late diastolic mitral and tricuspid inflow velocities increased (1.3 +/- 0.2 to 1.6 +/- 0.5, p = 0.02; 1.0 +/- 0.1 to 1.6 +/- 0.3, p = 0.003). Early diastolic tissue Doppler velocities increased at both the lateral and septal mitral annulus (7.6 +/- 1.5 to 9.3 +/- 2.5 cm/s, p = 0.009; and 6.6 +/- 1.4 to 7.7 +/- 1.7 cm/s; p = 0.028, respectively) and for their 2-site average (7.2 +/- 1.0 to 8.5 +/- 1.7 cm/s, p = 0.007). Early diastolic tricuspid annular velocity increased (7.2 +/- 2.8 to 10.6 +/- 2.3 cm/s, p <0.001) as did the ratio of early-to-late tricuspid annular diastolic velocity (0.9 +/- 0.4 to 1.1 +/- 0.2, p = 0.038). Tricuspid annular systolic velocity increased (8.6 +/- 2.5 to 10.3 +/- 2.7 cm/s, p = 0.037). In patients with severe obesity, significant weight loss results in an increase in tricuspid annular systolic and early diastolic velocities and mitral annular early diastolic velocities.

Obesity and hypertension: two epidemics or one?

The association between obesity and hypertension is well documented, although the exact nature of this relation remains unclear. Sympathetic nervous and renin-angiotensin-aldosterone system activation appear to play an important role in the sodium and water retention, rightward shift in the pressure-natriuresis, and blood pressure elevation observed in obese individuals. Visceral obesity and the ectopic deposition of adipose tissue may be important in the activation of these systems and in the target organ damage that ensues. Weight loss is critical in the effective management of obesity hypertension and the accompanying target organ damage, although recidivism rates are high. However, prevention of weight gain should be the major priority for combating hypertension and its consequences in the future. The present review will provide an overview of our understanding of the etiology, pathophysiology, and treatment of obesity hypertension. Our focus is on the state of knowledge in humans. The potential role of abdominal obesity is considered throughout our review. We refer to relevant animal literature for supportive evidence and where little or no data in humans are available.

Improvement in hypertrophic cardiomyopathy after significant weight loss: case report

A 17-year-old obese boy found to have familial apical hypertrophic cardiomyopathy on routine screening was enrolled in a weight loss program on the basis of the hypothesis that significant weight loss would improve his cardiac status. He was followed with serial dual-energy x-ray absorptiometry, electrocardiography, echocardiography, and blood pressure and pulse rate measurements. Within 1 year, he lost 49 kg, with a body mass index reduction from 43.6 to 28.1 kg/m2 and associated reductions in systolic blood pressure, diastolic blood pressure, pulse pressure, mean heart rate, rate pressure product, and echocardiographic indices of left ventricular mass that resulted in a change from the initial geometric finding of eccentric left ventricular hypertrophy to a "normal" left ventricular mass with minimal asymmetric apical left ventricular thickening. Significant weight loss in an obese adolescent with presumed familial apical hypertrophic cardiomyopathy was associated with striking improvement in cardiac functional indices, which could have profound implications for long-term cardiovascular risk.

Mechanisms of obesity-associated cardiovascular and renal disease

Obesity is the most common nutritional disorder in the United States. Growing evidence suggests that obesity initiates a cascade of disorders including hypertension, diabetes, atherosclerosis, and chronic renal disease, many of which are interdependent. Abnormal kidney function, caused by increased renal tubular reabsorption, initiates volume expansion and increased blood pressure during excess weight gain, and the hypertension and metabolic abnormalities associated with obesity, in turn, contribute to chronic renal disease. Obesity causes cardiac and vascular disease through well-known mediators such as hypertension, type II diabetes, and dyslipidemia, but there is evidence for less well-characterized mediators such as chronic inflammation and hypercoagulation. Although obesity is increasingly recognized as a serious health problem, there are still many unanswered questions about how the multiple disorders associated with excess weight gain interact to cause cardiovascular and renal disease. Also, there are few studies that have examined whether sustained weight loss in obese subjects can reverse these changes. In view of the "epidemic" of obesity in our country and the excess burden of cardiovascular and renal disease in minority populations, addressing these issues is of paramount importance for the Jackson Heart Study, as well as for other national health initiatives.