The paradox of obesity cardiomyopathy and the potential for weight loss as a therapy

The Unrestrained Overeating Behavior and Clinical Perspective

Obesity-related co-morbidities decrease life quality, reduce working ability, and lead to early death. In the adult population, eating addiction manifests with excessive food consumption and the unrestrained overeating behavior, which is associated with increased risk of morbidity and mortality and defined as the binge eating disorder (BED). This hedonic intake is correlated with fat preference and the total amount of dietary fat consumption is the most potent risk factor for weight gain. Long-term BED leads to greater sensitivity to the rewarding effects of palatable foods and results in obesity fatefully. Increased plasma concentrations of non-esterified free fatty acids and lipid-overloaded hypertrophic adipocytes may cause insulin resistance. In addition to dietary intake of high-fat diet, sedentary lifestyle leads to increased storage of triglycerides not only in adipose tissue but also ectopically in other tissues. Lipid-induced apoptosis, ceramide accumulation, reactive oxygen species overproduction, endoplasmic reticulum stress, and mitochondrial dysfunction play role in the pathogenesis of lipotoxicity. Food addiction and BED originate from complex action of dopaminergic, opioid, and cannabinoid systems. BED may also be associated with both obesity and major depressive disorder. For preventing morbidity and mortality, as well as decreasing the impact of obesity-related comorbidities in appropriately selected patients, opiate receptor antagonists and antidepressant combination are recommended. Pharmacotherapy alongside behavioral management improves quality of life and reduces the obesity risk; however, the number of licensed drugs is very few. Thus, stereotactic treatment is recommended to break down the refractory obesity and binge eating in obese patient. As recent applications in the field of non-invasive neuromodulation, transcranial magnetic stimulation and transcranial direct current stimulation are thought to be important in image-guided deep brain stimulation in humans. Chronic overnutrition most likely provides repetitive and persistent signals that up-regulate inhibitor of nuclear factor kappa B (NF-κB) kinase beta subunit/NF-κB (IKKβ/NF-κB) in the hypothalamus before the onset of obesity. However, how the mechanisms of high-fat diet-induced peripheral signals affect the hypothalamic arcuate nucleus remain largely unknown.

Is the obesity paradox in outpatients with heart failure reduced ejection fraction real?

Background

The obesity occurrence has achieved epidemic levels worldwide and several studies indicate a paradoxical similarity among obesity and the prognosis in heart failure (HF). The primary objective was to understand the association between body mass index (BMI) and heart failure with reduced ejection fraction (HFREF) of ischemic etiology in outpatients, using mortality as a parameter. The secondary objectives were to determine the differences in HF functional class, pharmacological therapy and evaluate the prognostic value of MAGGIC Score in this population.

Methods

We analyzed 1,556 medical records from the HF outpatient clinic of a quaternary hospital and 242 were selected according to the criteria. Most were male, average age 62.6 (56-70), BMI 18.5-24.9 = 35.1%, 25-29.9 = 37.2%, 30-34.9 = 17.8%, 35-39.9 = 7%; BMI <18.5 and >40 groups were eliminated from the central analyzes because of scarce testing.

Results

BMI 30-34.9 and BMI 18.5-24.9 had the best prognosis, BMI 25-29.9 had an average performance, and BMI -39.9 group provided the worst outcome (p = 0.123). In the subcategory analysis, BMI 30-34.9 group had a better prognosis compared to the BMI 35-39.9 group (p = 0.033). In the multivariate analysis The MAGGIC score was not able to foretell mortality in this population according to BMI.

Conclusion

In not hospitalized patients with HFREF of ischemic etiology, obesity was not a protective factor.

Adverse right ventricular remodelling, function, and stress responses in obesity: insights from cardiovascular magnetic resonance

AIMS

We aimed to determine the effect of increasing body weight upon right ventricular (RV) volumes, energetics, systolic function, and stress responses using cardiovascular magnetic resonance (CMR).

METHODS AND RESULTS

We first determined the effects of World Health Organization class III obesity [body mass index (BMI) > 40 kg/m2, n = 54] vs. healthy weight (BMI < 25 kg/m2, n = 49) upon RV volumes, energetics and systolic function using CMR. In less severe obesity (BMI 35 ± 5 kg/m2, n = 18) and healthy weight controls (BMI 21 ± 1 kg/m2, n = 9), we next performed CMR before and during dobutamine to evaluate RV stress response. A subgroup undergoing bariatric surgery (n = 37) were rescanned at median 1 year to determine the effects of weight loss. When compared with healthy weight, class III obesity was associated with adverse RV remodelling (17% RV end-diastolic volume increase, P < 0.0001), impaired cardiac energetics (19% phosphocreatine to adenosine triphosphate ratio reduction, P < 0.001), and reduction in RV ejection fraction (by 3%, P = 0.01), which was related to impaired energetics (R = 0.3, P = 0.04). Participants with less severe obesity had impaired RV diastolic filling at rest and blunted RV systolic and diastolic responses to dobutamine compared with healthy weight. Surgical weight loss (34 ± 15 kg weight loss) was associated with improvement in RV end-diastolic volume (by 8%, P = 0.006) and systolic function (by 2%, P = 0.03).

CONCLUSION

Increasing body weight is associated with significant alterations in RV volumes, energetic, systolic function, and stress responses. Adverse RV modelling is mitigated with weight loss. Randomized trials are needed to determine whether intentional weight loss improves symptoms and outcomes in patients with obesity and heart failure.

Nutrition in chronic heart failure patients: a systematic review

Nutrition is the primary source of energy production for myocardial contractility and to maintaining cardiac efficiency. Although many studies provided evidence of the benefits of nutritional intervention in chronic heart failure patients (CHF), these effects are not still completely understood. We searched in PubMed and Embase articles related to the following keywords: "chronic heart failure" with "diet," "nutrition," "insulin resistance," and "caloric restriction." Of the 975 retrieved articles, 20 have been selected. The primary endpoint was the left ventricular (LV) function and the secondary mortality rate in HF patients. Some studies showed that the Mediterranean diet (MedDiet) had a beneficial effect on cardiac function, while others did not find any positive impact. Nutritional supplements and hypercaloric intake had positive effects on underweight HF patients, while hypocaloric diet was beneficial in obese HF patients improving glucose control and cardiac function. The effect of MedDiet in HF patients showed conflicting results. Changes in the dietary pattern can reduce the evolution of HF, considering not only the quality of food but also the caloric intake. The discriminant factor to prescribe a diet regime in HF patients is represented by body mass index (BMI). A well-balanced caloric diet represents an effective therapy in overweight HF patients to reduce the mortality rate. Long-term studies evaluating cause-effect of energy and macronutrients intake on cardiac function in HF patients are necessary.

Obesity in the absence of comorbidities is not related to clinically meaningful left ventricular hypertrophy

Obesity is associated with the development of left ventricular (LV) hypertrophy. Whether obesity in in the absence of comorbidities can cause LV hypertrophy to an extent which could create diagnostic uncertainty with pathological states (such as hypertrophic cardiomyopathy) is unknown. We used cine cardiovascular magnetic resonance imaging to precisely measure LV wall thickness in the septum and lateral wall in 764 people with body mass indices ranging from 18.5 kg/m2 to 59.2 kg/m2 in the absence of major comorbidities. Obesity was related to LV wall thickness across the cohort (basal septum r 0.30, P < 0.001 and basal lateral wall r 0.18, P < 0.001). Although no participant had hypertension, these associations remained highly significant after controlling for systolic blood pressure (all P < 0.01). Each 10 kg/m2 increase in BMI was associated with an increase in basal septal wall thickness of 1.0 mm males and 0.8 mm in females, with no statistically significant difference between genders (P = 0.1). Even in class 3 obesity (BMI > 40 kg/m2), no LV wall thickness > 13.4 mm in males or > 12.7 mm in females was observed in this cohort. We confirm that obesity in the absence of comorbidities is associated with LV hypertrophy, and establish that the magnitude of this change is modest even in severe obesity. LV hypertrophy > 14 mm cannot safely be attributed to obesity alone and alternative diagnoses should be considered.

Preserved Skeletal Muscle Mitochondrial Function, Redox State, Inflammation and Mass in Obese Mice with Chronic Heart Failure

Background: Skeletal muscle (SM) mitochondrial dysfunction, oxidative stress, inflammation and muscle mass loss may worsen prognosis in chronic heart failure (CHF). Diet-induced obesity may also cause SM mitochondrial dysfunction as well as oxidative stress and inflammation, but obesity per se may be paradoxically associated with high SM mass and mitochondrial adenosine triphosphate (ATP) production, as well as with enhanced survival in CHF. Methods: We investigated interactions between myocardial infarction(MI)-induced CHF and diet-induced obesity (12-wk 60% vs. standard 10% fat) in modulating gastrocnemius muscle (GM) mitochondrial ATP and tissue superoxide generation, oxidized glutathione (GSSG), cytokines and insulin signalling activation in 10-wk-old mice in the following groups: lean sham-operated, lean CHF (LCHF), obese CHF (ObCHF; all n = 8). The metabolic impact of obesity per se was investigated by pair-feeding ObCHF to standard diet with stabilized excess body weight until sacrifice at wk 8 post-MI. Results: Compared to sham, LCHF had low GM mass, paralleled by low mitochondrial ATP production and high mitochondrial reative oxygen species (ROS) production, pro-oxidative redox state, pro-inflammatory cytokine changes and low insulin signaling (p < 0.05). In contrast, excess body weight in pair-fed ObCHF was associated with high GM mass, preserved mitochondrial ATP and mitochondrial ROS production, unaltered redox state, tissue cytokines and insulin signaling (p = non significant vs. Sham, p < 0.05 vs. LCHF) despite higher superoxide generation from non-mitochondrial sources. Conclusions: CHF disrupts skeletal muscle mitochondrial function in lean rodents with low ATP and high mitochondrial ROS production, associated with tissue pro-inflammatory cytokine profile, low insulin signaling and muscle mass loss. Following CHF onset, obesity per se is associated with high skeletal muscle mass and preserved tissue ATP production, mitochondrial ROS production, redox state, cytokines and insulin signaling. These paradoxical and potentially favorable obesity-associated metabolic patterns could contribute to reported obesity-induced survival advantage in CHF.

Sinensol-C Isolated from Spiranthes sinensis Inhibits Adipogenesis in 3T3-L1 Cells through the Regulation of Adipogenic Transcription Factors and AMPK Activation

Obesity is an abnormal medical condition caused by accumulation of body fat that presents negative health impacts. Adipocyte hyperplasia, also known as adipogenesis, is one of the major manifestations of obesity. In the present study, we isolated six phenanthrene derivatives (compounds 1–6) from the ethyl acetate fraction of Spiranthes sinensis and investigated their anti-adipogenic activity. We found that among the six phenanthrene derivatives, compound 6 (sinensol-C) exhibited strong inhibitory activity against intracellular lipid accumulation in 3T3-L1 adipocytes, with an IC₅₀ value of 12.67 μM. Sinensol-C remarkably suppressed the accumulation of lipid droplets and adipogenesis, via down-regulation of adipogenic transcription factors, including peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), sterol regulatory element binding protein-1 (SREBP-1c), fatty acid synthase (FAS), and fatty acid binding protein 4 (FABP4), during adipocyte differentiation in 3T3-L1 cells. In addition, treatment with sinensol-C significantly increased the adenosine monophosphate-activated protein kinase (AMPK) activity in 3T3-L1 cells. Taken together, these data strongly suggest that sinensol-C regulates adiogenesis via down-regulation of adipogenic transcription factors and up-regulation of AMPK. Furthermore, this is the first study that demonstrates that sinensol-C has the capacity to modulate adipogenesis.

SIRT3 Ablation Deteriorates Obesity-Related Cardiac Remodeling by Modulating ROS-NF-κB-MCP-1 Signaling Pathway

Obesity and the associated complications are a major public health issue as obesity incidence increases yearly, worldwide. Effects of obesity on heart failure have been reported previously. Obesity-related cardiac remodeling includes structural and functional dysfunctions, in which cardiac inflammation and fibrosis play a key role. The main mitochondrial deacetylase, SIRT3 participates in numerous cellular processes; however, its role in obesity-related cardiac remodeling remains unclear. In our study, high-fat diet (HFD) feeding induced downregulation of SIRT3 protein level in mice. SIRT3-KO mice fed on HFD exhibited higher cardiac dysfunction and cardiac remodeling compared with the wild-type controls. Further study revealed increases in collagen accumulation and inflammatory cytokine expression including MCP-1, IL-6, TGF-β, TNF-α in mice fed on HFD compared with chow diet, with higher levels observed in SIRT3-KO mice. Furthermore, significantly high levels of cardiac MCP-1 expression and macrophage infiltration, and ROS generation and activated NF-κB were observed in HFD-fed SIRT3-KO mice. We presumed that SIRT3 ablation-mediated MCP-1 upregulation is attributed to ROS-NF-κB activation. Thus, we concluded that SIRT3 prevents obesity-related cardiac remodeling by attenuating cardiac inflammation and fibrosis, through modulation of ROS-NF-κB-MCP-1 pathway.

Up regulated Tmbim1 activation promotes high fat diet (HFD)-induced cardiomyopathy by enhancement of inflammation and oxidative stress

The prevalence of cardiomyopathy due to metabolic stress has up-regulated dramatically; nevertheless, its molecular mechanisms remain unclear. Here we suggested that transmembrane BAX inhibitor motif-containing 1 (Tmbim1) is down-regulated in the hearts of mice fed with high fat diet (HFD). We provided evidence that Tmbim1 knockout (KO) accelerated HFD-induced metabolic disorders in mice, as supported by the remarkable increase of fasting serum glucose and insulin levels. HFD-induced cardiac dysfunctions were greatly intensified by the loss of Tmbim1, along with higher levels of lactate dehydrogenase (LDH) and creatine kinase (CK) in serum. In addition, Tmbim1 deletion significantly enhanced lipid accumulation in heart of mice administrated with HFD. Furthermore, Tmbim1 knockout reinforced myocardial inflammation, evidenced by increasing the expression of pro-inflammatory cytokines (interleukin 1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α)), and the activation of nuclear factor-κB (NF-κB) signaling pathway. Tmbim1 deficiency strengthened oxidative damage in hearts of HFD-fed mice, accompanied with a significant reduction of nuclear factor-erythroid 2 related factor 2 (Nrf-2) pathway. In palmitate (PA)-treated primary cardiomyocytes, Tmbim1 ablation markedly enhanced cell inflammation and oxidative stress, which were abolished by the suppression of ROS generation and NF-κB activation. Taken together, these findings suggested that Tmbim1 might be a key suppressor of metabolic stress-induced cardiomyopathy, which could be a promising target for the treatment of metabolic syndrome-triggered myocardial damage and heart failure.

Effects of intentional weight loss in patients with obesity and heart failure: a systematic review

OBJECTIVE

Obesity is an independent risk factor for the development of heart failure, and the two commonly co-exist. The European Society of Cardiology does not provide guidance regarding weight loss strategies in heart failure. The aim of this study was to systematically review the evidence for outcomes following intentional weight loss in patients with heart failure and obesity.

METHOD

A systematic review of English articles was undertaken using databases PubMed, Embase and CENTRAL. Randomized controlled trials and observational studies reporting outcomes following intentional weight loss by lifestyle, surgical or pharmacotherapy intervention in patients with obesity and heart failure were included.

RESULTS

Four randomized controlled trials and seven observational studies were identified. Two randomized controlled trials used diet and exercise as an intervention, one used diet alone and one used a pharmacological intervention (orlistat). All but one reported significant weight loss. Two reported improvement in exercise capacity and quality of life. One reported improvement in New York Heart Association functional class in heart failure with preserved ejection fraction. The observational studies, five of which reported on outcomes following bariatric surgery, despite being small, heterogeneous and high risk of bias, suggested a trend in improvement of left ventricular function, quality of life and exercise capacity following weight loss.

CONCLUSION

Weight loss is achievable with lifestyle intervention in those with heart failure and obesity and may result in improvements in New York Heart Association classification, quality of life and exercise capacity.

Joint statement of the European Association for the Study of Obesity and the European Society of Hypertension: obesity and heart failure

Obese individuals are more likely to develop heart failure. Yet, once heart failure is established, the impact of overweight and obesity on prognosis and survival is unclear. The purpose of this joint scientific statement of the European Association for the Study of Obesity and the European Society of Hypertension is to provide an overview on the current scientific literature on obesity and heart failure in terms of prognosis, mechanisms, and clinical management implications. Moreover, the document identifies open questions that ought to be addressed. The need for more tailored weight management recommendations in heart failure will be emphasized and, in line with the emerging evidence, aims to distinguish between primary disease and secondary outcome prevention. In the primary prevention of heart failure, it appears prudent advising obese individuals to lose or achieve a healthy body weight, especially in those with risk factors such as hypertension or type 2 diabetes. However, there is no evidence from clinical trials to guide weight management in overweight or obese patients with established heart failure. Prospective clinical trials are strongly encouraged.

Metabolic remodeling in hypertrophied and failing myocardium: a review

The energy starvation hypothesis proposes that maladaptive metabolic remodeling antedates, initiates, and maintains adverse contractile dysfunction in heart failure (HF). Better understanding of the cardiac metabolic phenotype and metabolic signaling could help identify the role metabolic remodeling plays within HF and the conditions known to transition toward HF, including "pathological" hypertrophy. In this review, we discuss metabolic phenotype and metabolic signaling in the contexts of pathological hypertrophy and HF. We discuss the significance of alterations in energy supply (substrate utilization, oxidative capacity, and phosphotransfer) and energy sensing using observations from human and animal disease models and models of manipulated energy supply/sensing. We aim to provide ways of thinking about metabolic remodeling that center around metabolic flexibility, capacity (reserve), and efficiency rather than around particular substrate preferences or transcriptomic profiles. We show that maladaptive metabolic remodeling takes multiple forms across multiple energy-handling domains. We suggest that lack of metabolic flexibility and reserve (substrate, oxidative, and phosphotransfer) represents a final common denominator ultimately compromising efficiency and contractile reserve in stressful contexts.

Eat and Death: Chronic Over-Eating

Obesity-related co-morbidities decrease life quality, reduce working ability and lead to early death. The total amount of dietary fat consumption may be the most potent food-related risk factor for weight gain. In this respect, dietary intake of high-caloric, high-fat diets due to chronic over-eating and sedentary lifestyle lead to increased storage of triglycerides not only in adipose tissue but also ectopically in other tissues . Increased plasma concentrations of non-esterified free fatty acids and lipid-overloaded hypertrophic adipocytes may cause insulin resistance in an inflammation-independent manner. Even in the absence of metabolic disorders, mismatch between fatty acid uptake and utilization leads to the accumulation of toxic lipid species resulting in organ dysfunction. Lipid-induced apoptosis, ceramide accumulation, reactive oxygen species overproduction, endoplasmic reticulum stress, and mitochondrial dysfunction may play role in the pathogenesis of lipotoxicity. The hypothalamus senses availability of circulating levels of glucose, lipids and amino acids, thereby modifies feeding according to the levels of those molecules. However, the hypothalamus is also similarly vulnerable to lipotoxicity as the other ectopic lipid accumulated tissues. Chronic overnutrition most likely provides repetitive and persistent signals that up-regulate inhibitor of nuclear factor kappa B kinase beta subunit/nuclear factor kappa B (IKKβ/NF-κB) in the hypothalamus before the onset of obesity. However, the mechanisms by which high-fat diet induced peripheral signals affect the hypothalamic arcuate nucleus remain largely unknown. In this chapter, besides lipids and leptin, the role of glucose and insulin on specialized fuel-sensing neurons of hypothalamic neuronal circuits has been debated.

The obesity paradox in patients with severe soft tissue infections

BACKGROUND

The "obesity paradox" has been demonstrated in chronic diseases but not in acute surgery. We sought to determine whether obesity is associated with improved outcomes in patients with severe soft tissue infections (SSTIs).

METHODS

The 2006 to 2010 Nationwide Inpatient Sample was used to identify adult patients with SSTIs. Patients were categorized into nonobese and obese (nonmorbid [body mass index 30 to 39.9] and morbid [body mass index ≥ 40]). Logistic regression provided risk-adjusted association between obesity categories and inhospital mortality.

RESULTS

There were 2,868 records with SSTI weighted to represent 14,080 patients. Obese patients were less likely to die in hospital than nonobese patients (odds ratio [OR] = .42; 95% confidence interval [CI], .25 to .70; P = .001). Subanalysis revealed a similar trend, with lower odds of mortality in nonmorbid obesity (OR = .46; 95% CI, .23 to .91; P = .025) and morbid obesity (OR = .39; 95% CI, .19 to .80; P = .011) groups.

CONCLUSIONS

Obesity is independently associated with reduced inhospital mortality in patients with SSTI regardless of the obesity classification. This suggests that the obesity paradox exists in this acute surgical population.

Diabetes mellitus related biomarker: The predictive role of growth-differentiation factor-15

Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine, which belongs to super family of the transforming growth factor beta. GDF-15 is widely presented in the various cells (macrophages, vascular smooth muscle cells, adipocytes, cardiomyocytes, endothelial cells, fibroblasts), tissues (adipose tissue, vessels, tissues of central and peripheral nervous system) and organs (heart, brain, liver, placenta) and it plays an important role in the regulation of the inflammatory response, growth and cell differentiation. Elevated GDF-15 was found in patients with established CV diseases including hypertension, stable coronary artery disease, acute coronary syndrome, myocardial infarction, ischemic and none ischemic-induced cardiomyopathies, heart failure, atrial fibrillation, as well as stroke, type two diabetes mellitus (T2DM), chronic kidney disease, infection, liver cirrhosis, malignancy. Therefore, aging, smoking, and various environmental factors, i.e. chemical pollutants are other risk factors that might increase serum GDF-15 level. Although GDF-15 has been reported to be involved in energy homoeostasis and weight loss, to have anti-inflammatory properties, and to predict CV diseases and CV events in general or established CV disease population, there is no large of body of evidence regarding predictive role of elevated GDF-15 in T2DM subjects. The mini review is clarified the role of GDF-15 in T2DM subjects.