Cardiac remodeling in obesity

Consumption of a high-fat-high-sucrose diet partly diminishes mechanical and structural adaptations of cardiac muscle following resistance training

[Purpose]

The purpose of this study was to investigate the effects of a high-fat high-sucrose (HFHS) diet on previously reported adaptations of cardiac morphological and contractile properties to resistance training.

[Methods]

Twelve-week-old rats participated in 12-weeks of resistance exercise training and consumed an HFHS diet. Echocardiography and skinned cardiac muscle fiber bundle testing were performed to determine the structural and mechanical adaptations.

[Results]

Compared to chow-fed sedentary animals, both HFHS- and chow-fed resistance-trained animals had thicker left ventricular walls. Isolated trabecular fiber bundles from chow-fed resistance-trained animals had greater force output, shortening velocities, and calcium sensitivities than those of chow-fed sedentary controls. However, trabeculae from the HFHS resistance-trained animals had greater force output but no change in unloaded shortening velocity or calcium sensitivity than those of the chow-fed sedentary group animals.

[Conclusion]

Resistance exercise training led to positive structural and mechanical adaptations of the heart, which were partly offset by the HFHS diet.

Long-Term High-Fat Diet Inhibits the Recovery of Myocardial Mitochondrial Function After Chronic Hypoxia Reoxygenation in Rats

Yan, Jun, Kang Song, Sisi Zhou, and Ri-Li Ge. Long-term high-fat diet inhibits the recovery of myocardial mitochondrial function after chronic hypoxia reoxygenation in rats. High Alt Med Biol. 16:000-000, 2021. Aims: A high-fat diet (HFD) is associated with cardiovascular diseases and mitochondrial dysfunction. Obesity incidence is low at high altitudes, but the impact of HFD, which is closely associated with obesity at high altitudes, and the effects of reoxygenation on the heart are unclear. In this study, we investigated the effects of long-term HFD consumption on mitochondrial function in the myocardium after chronic hypoxia reoxygenation. Main Methods: Sprague-Dawley rats were randomized into the following six groups: normoxia groups, including a control group and HFD group; chronic hypoxia groups, including a normal chow diet (CH-CD) group and an HFD (CH-HFD) group; and hypoxic-reoxygenated (HR) groups, including a hypoxia-reoxygenation normal chow diet (HR-CD) group and a hypoxia-reoxygenation HFD (HR-HFD) group. All rats were euthanized in this study. Results: We found that chronic hypoxia aggravated myocardial mitochondrial dysfunction. The Flameng score (in which the higher the score, the more severe the mitochondrial damage) was used to assess the extent of mitochondrial structural damage. Compared with the control group and HFD group, the Flameng scores of the CH-CD and CH-HFD groups were significantly increased, respectively [1.260 ± 0.063 vs. 0.68 ± 0.05 (p < 0.05); 2.03 ± 0.07 vs. 1.48 ± 0.05 (p < 0.05)]. Moreover, progressive reoxygenation facilitated the recovery of myocardial mitochondrial function; this process was inhibited by long-term HFD. After reoxygenation, the Flameng scores in the HR-CD group became comparable to those in the CH-CD group [0.86 ± 0.05 vs. 1.26 ± 0.06 (p < 0.05)]. However, no significant changes were observed in the Flameng score between the HR-HFD and CH-HFD groups. Significance: Long-term HFD consumption inhibits myocardial mitochondrial function after reoxygenation. This finding may be helpful for the prevention and control of risk factors related to cardiovascular diseases in plateau residents.

Social inequalities and trends in pre-pregnancy body mass index in Swedish women

Obesity rates in adolescence and young adulthood have increased in Sweden, reflecting global trends. To which extent this occurs across different socioeconomic strata has not been clarified. The aim of the present study was to investigate trends in social inequalities in body mass index (BMI) in young/mid-adulthood Swedish women. We obtained weight and height for all women aged 20–45 years, at their first registered pregnancy (< 12 weeks of gestation) in the Swedish Medical Birth Register 1982–2013 (1,022,330, mean age = 28.8 years), documenting education and county of residence. Trends in mean BMI and in the prevalence of BMI categories between 1982 and 2013 were estimated across education levels and geographical location. Overall, mean BMI increased from 22.7 kg/m² (SD 3.2) to 24.3 kg/m² (SD 4.4) between 1982 and 2013. Simultaneously, the prevalence of overweight and obesity (BMI ≥ 25 kg/m²) increased from 18.1 to 33.4% while that of moderate obesity (BMI ≥ 30 to < 35 kg/m²) and severe obesity (BMI ≥ 35 kg/m²) increased markedly from 3.4 and 0.4% to 7.4 and 3.1%, respectively. The prevalence of moderate and severe obesity more than doubled during the study period across all educational levels. In conclusion, BMI and moderate and severe obesity increased markedly among young/mid-adulthood Swedish women regardless of education with a widening gap between those with lower and higher education. These growing social inequalities in BMI are likely to cause a rising divide in serious health problems following early and long-lasting obesity.

Atrial and Ventricular Structural and Functional Alterations in Obese Children

Background and objectives: Childhood obesity has reached epidemic levels in the world. Obesity in children is defined as a body mass index (BMI) equal to or above the 95th percentile for age and sex. The aim of this study was to determine early changes in cardiac structure and function in obese children by comparing them with their nonobese peers, using echocardiography methods. Materials and methods: The study enrolled 35 obese and 37 age-matched nonobese children. Standardized 2-dimensional (2D), pulsed wave tissue Doppler, and 2D speckle tracking echocardiography were performed. The z-score BMI and lipid metabolism were assessed in all children. Results: Obese children (aged 13.51 ± 2.15 years; 20 boys; BMI z-score of 0.88 ± 0.63) were characterized by enlarged ventricular and atrial volumes, a thicker left ventricular posterior wall, and increased left ventricular mass. Decreased LV and RV systolic and diastolic function was found in obese children. Atrial peak negative (contraction) strain (−2.05% ± 2.17% vs. −4.87% ± 2.97%, p < 0.001), LV and RV global longitudinal strain (−13.3% ± 2.88% vs. −16.87% ± 3.39%; −12.51% ± 10.09% vs. −21.51% ± 7.42%, p < 0.001), and LV global circumferential strain (−17.0 ± 2.7% vs. −19.5 ± 2.9%, p < 0.001) were reduced in obese children. LV torsion (17.94° ± 2.07° vs. 12.45° ± 3.94°, p < 0.001) and normalized torsion (2.49 ± 0.4°/cm vs. 1.86 ± 0.61°/cm, p = 0.001) were greater in obese than nonobese children. A significant inverse correlation was found between LV and RV global longitudinal strain and BMI (r = −0.526, p < 0.01; r = −0.434, p < 0.01) and total cholesterol (r = −0.417, p < 0.01). Multivariate analysis revealed that the BMI z-score was independently related to LV and RV global longitudinal strain as well as LV circumferential and radial strain. Conclusion: 2D speckle tracking echocardiography is beneficial in the early detection of regional LV systolic and diastolic dysfunctions, with preserved ejection fraction as well as additional RV and atrial involvement, in obese children. Obesity may negatively influence atrial and ventricular function, as measured by 2D speckle tracking echocardiography. Obese children, though they are apparently healthy, may have subclinical myocardial dysfunction.

Molecular basis of ventricular arrhythmogenicity in a Pgc-1α deficient murine model

Mitochondrial dysfunction underlying metabolic disorders such as obesity and diabetes mellitus is strongly associated with cardiac arrhythmias. Murine Pgc-1α-/- hearts replicate disrupted mitochondrial function and model the associated pro-arrhythmic electrophysiological abnormalities. Quantitative PCR, western blotting and histological analysis were used to investigate the molecular basis of the electrophysiological changes associated with mitochondrial dysfunction. qPCR analysis implicated downregulation of genes related to Na+-K+ ATPase activity (Atp1b1), surface Ca2+ entry (Cacna1c), action potential repolarisation (Kcnn1), autonomic function (Adra1d, Adcy4, Pde4d, Prkar2a), and morphological properties (Myh6, Tbx3) in murine Pgc-1α-/- ventricles. Western blotting revealed reduced NaV1.5 but normal Cx43 expression. Histological analysis revealed increased tissue fibrosis in the Pgc-1α-/- ventricles. These present findings identify altered transcription amongst a strategically selected set of genes established as encoding proteins involved in cardiac electrophysiological activation and therefore potentially involved in alterations in ventricular activation and Ca2+ homeostasis in arrhythmic substrate associated with Pgc-1α deficiency. They complement and complete previous studies examining such expression characteristics in the atria and ventricles of Pgc-1 deficient murine hearts.

The effects of two types of Western diet on the induction of metabolic syndrome and cardiac remodeling in obese rats

Metabolic syndrome (MetS) include obesity as a critical feature and is strongly associated with risk of cardiovascular disease (CVD). Insights into mechanisms involved in the pathophysiology of these clinical manifestations are essential for the development of therapeutic strategies. Thus, Western diets (WD) have been widely employed in diet-induced obesity (DIO) model. However, there are variations in fat and sugar proportions of such diets, making comparisons challenging. We aimed to assess the impact of two types of the WD on metabolic status and cardiac remodeling, to achieve a DIO model that better mimics the human pathogenesis of MetS-induced CVD. Male Wistar rats were distributed into three groups: control diet, Western diet fat (WDF), and Western diet sugar (WDS) for 41 weeks. Metabolic and inflammatory parameters and cardiac changes were characterized. WDF and WDS feeding promoted higher serum triglycerides, glucose intolerance, and insulin resistance, while just WDF presented inflammation in adipose tissue. WDF-fed rats showed increased catalase activity and malondialdehyde (MDA) and carbonyl protein levels, suggesting cardiac oxidative stress, while WDS-fed rats only raised MDA. Both WD equally elevated protein expressions involved in lipid metabolism, but only WDF downregulated the glycolysis pathway. Furthermore, the mechanical myocardial function was impaired in obese rats, being more relevant in WDF. In conclusion, both WD effectively triggered MetS features, although inflammation was detected just on the WDF-fed animals. Moreover, the WDF promoted a more pronounced functional, metabolic, and oxidative cardiac disorder, suggesting to be an adequate model for studying CVD in the scenario of MetS.

Deficiency of ataxia-telangiectasia mutated kinase modulates functional and biochemical parameters of the heart in response to Western-type diet

Ataxia-telangiectasia mutated (ATM) kinase deficiency exacerbates heart dysfunction late after myocardial infarction. Here, we hypothesized that ATM deficiency modulates Western-type diet (WD)-induced cardiac remodeling with an emphasis on functional and biochemical parameters of the heart. Weight gain was assessed in male wild-type (WT) and ATM heterozygous knockout (hKO) mice on weekly basis, whereas cardiac functional and biochemical parameters were measured 14 wk post-WD. hKO-WD mice exhibited rapid body weight gain at weeks 5, 6, 7, 8, and 10 versus WT-WD. WD decreased percent fractional shortening and ejection fraction, and increased end-systolic volumes and diameters to a similar extent in both genotypes. However, WD decreased stroke volume, cardiac output, peak velocity of early ventricular filling, and aortic ejection time and increased isovolumetric relaxation time (IVRT) and Tei index versus WT-NC (normal chow). Conversely, IVRT, isovolumetric contraction time, and Tei index were lower in hKO-WD versus hKO-NC and WT-WD. Myocyte apoptosis and hypertrophy were higher in hKO-WD versus WT-WD. WD increased fibrosis and expression of collagen-1α1, matrix metalloproteinase (MMP)-2, and MMP-9 in WT. WD enhanced AMPK activation, while decreasing mTOR activation in hKO. Akt and IKK-α/β activation, and Bax, PARP-1, and Glut-4 expression were higher in WT-WD versus WT-NC, whereas NF-κB activation and Glut-4 expression were lower in hKO-WD versus hKO-NC. Circulating concentrations of IL-12(p70), eotaxin, IFN-γ, macrophage inflammatory protein (MIP)-1α, and MIP-1β were higher in hKO-WD versus WT-WD. Thus, ATM deficiency accelerates weight gain, induces systolic dysfunction with increased preload, and associates with increased apoptosis, hypertrophy, and inflammation in response to WD.NEW & NOTEWORTHY Ataxia-telangiectasia mutated (ATM) kinase deficiency in humans associates with enhanced susceptibility to ischemic heart disease. Here, we provide evidence that ATM deficiency accelerates body weight gain and associates with increased cardiac preload, hypertrophy, and apoptosis in mice fed with Western-type diet (WD). Further investigations of the role of ATM deficiency in WD-induced alterations in function and biochemical parameters of the heart may provide clinically applicable information on treatment and/or nutritional counseling for patients with ATM deficiency.

Nonalcoholic Fatty Liver Disease: An Emerging Driver of Cardiac Arrhythmia

Cardiac arrhythmias and the resulting sudden cardiac death are significant cardiovascular complications that continue to impose a heavy burden on patients and society. An emerging body of evidence indicates that nonalcoholic fatty liver disease (NAFLD) is closely associated with the risk of cardiac arrhythmias, independent of other conventional cardiometabolic comorbidities. Although most studies focus on the relationship between NAFLD and atrial fibrillation, associations with ventricular arrhythmias and cardiac conduction defects have also been reported. Mechanistic investigations suggest that a number of NAFLD-related pathophysiological alterations may potentially elicit structural, electrical, and autonomic remodeling in the heart, contributing to arrhythmogenic substrates in the heart. NAFLD is now the most common liver and metabolic disease in the world. However, the upsurge in the prevalence of NAFLD as an emerging risk factor for cardiac arrhythmias has received little attention. In this review, we summarize the clinical evidence and putative pathophysiological mechanisms for the emerging roles of NAFLD in cardiac arrhythmias, with the purpose of highlighting the notion that NAFLD may serve as an independent risk factor and a potential driving force in the development and progression of cardiac arrhythmias.

The effect of Systolic and diastolic blood pressure on Tp-e interval in patients divided according to World Health Organization classification for body mass index

Background: Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio are electrocardiographic markers and indices of ventricular arrhythmogenic events. We aimed to investigate ventricular repolarization in normal weight, overweight, obese and morbidly obese individuals by using ECG parameters including the above markers.Methods: A total of 310 obese patients with various cardiac complaints, who were admitted to our outpatient clinic between May 2020 and January 2021, were prospectively included in the study. Using the World Health Organization (WHO) body mass index (BMI) classification, patients were divided into four groups: normal weight (18.5-24.9 kg/m², n = 48), overweight (25-29.9 kg/m², n = 98), obese (30-39.9 kg/m², n = 119), and morbidly obese (>40 kg/m², n = 45).Results: The morbidly obese and normal groups were younger in age than the other two groups. The Tp-e interval values for Groups I-IV were 72.1 ± 6.9, 73.1 ± 6.2, 75.7 ± 7.3 and 81.1 ± 6.9, respectively, and significantly different (P < .001). We found that age, BMI, systolic blood pressure (BP) and diastolic BP were independent predictors of a prolonged Tp-e interval.Conclusions: The principal finding of our study was the gradual increase in Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio starting from the overweight stage and these parameters gradually increase in obese and morbidly obese patients. Additionally, systolic and diastolic blood pressure predicted Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio.

Short-term rapid weight loss induced by bariatric surgery improves ventricular ejection fraction in patients with severe obesity and heart failure

BACKGROUND

Obesity is a major risk factor for the development of metabolic syndrome, coronary artery disease, and heart failure (HF). Rapid weight loss following bariatric surgery can significantly improve outcomes for patients with these diseases.

OBJECTIVES

To assess whether bariatric surgery improves ventricular ejection fraction in patients with obesity who have heart failure.

SETTING

Private practice, United States.

METHODS

We conducted a retrospective review of echocardiographic changes in systolic functions in patients with obesity that underwent bariatric surgery at our institution. Patients were divided into 2 groups, those (1) without known preoperative HF and (2) with preoperative HF. We compared the left ventricular ejection fraction (LVEF) before and after bariatric surgery in both groups. Common demographics and co-morbidities were also analyzed.

RESULTS

A total of 68 patients were included in the analysis: 49 patients in group 1 and 19 in group 2. In group 1, 59.2% (n = 29) of patients were female, versus 57.9% (n = 11) in group 2. The excess body mass index lost at 12 months was 52.06 ± 23.18% for group 1 versus 67.12 ± 19.27% for group 2 (P = .0001). Patients with heart failure showed a significant improvement in LVEF, from 38.79 ± 13.26% before to 48.47 ± 14.57% after bariatric surgery (P = .039). Systolic function in patients from group 1 showed no significant changes (59.90 ± 6.37 mmHg) before and (59.88 ± 7.85 mmHg) after surgery (P = .98).

CONCLUSION

Rapid weight loss after bariatric surgery is associated with a considerable increase in LVEF and a significant improvement of systolic function.

Galangin Resolves Cardiometabolic Disorders through Modulation of AdipoR1, COX-2, and NF-κB Expression in Rats Fed a High-Fat Diet

Galangin is a natural flavonoid. In this study, we evaluated whether galangin could alleviate signs of metabolic syndrome (MS) and cardiac abnormalities in rats receiving a high-fat (HF) diet. Male Sprague–Dawley rats were given an HF diet plus 15% fructose for four months, and they were fed with galangin (25 or 50 mg/kg), metformin (100 mg/kg), or a vehicle for the last four weeks. The MS rats exhibited signs of MS, hypertrophy of adipocytes, impaired liver function, and cardiac dysfunction and remodeling. These abnormalities were alleviated by galangin (p < 0.05). Interleukin-6 and tumor necrosis factor-α concentrations and expression were high in the plasma and cardiac tissue in the MS rats, and these markers were suppressed by galangin (p < 0.05). These treatments also alleviated the low levels of adiponectin and oxidative stress induced by an HF diet in rats. The downregulation of adiponectin receptor 1 (AdipoR1) and cyclooxygenase-2 (COX-2) and the upregulation of nuclear factor kappa B (NF-κB) expression were recovered in the galangin-treated groups. Metformin produced similar effects to galangin. In conclusion, galangin reduced cardiometabolic disorders in MS rats. These effects might be linked to the suppression of inflammation and oxidative stress and the restoration of AdipoR1, COX-2, and NF-κB expression.

Metabolism and Chronic Inflammation: The Links Between Chronic Heart Failure and Comorbidities

Heart failure (HF) patients often suffer from multiple comorbidities, such as diabetes, atrial fibrillation, depression, chronic obstructive pulmonary disease, and chronic kidney disease. The coexistance of comorbidities usually leads to multi morbidity and poor prognosis. Treatments for HF patients with multi morbidity are still an unmet clinical need, and finding an effective therapy strategy is of great value. HF can lead to comorbidity, and in return, comorbidity may promote the progression of HF, creating a vicious cycle. This reciprocal correlation indicates there may be some common causes and biological mechanisms. Metabolism remodeling and chronic inflammation play a vital role in the pathophysiological processes of HF and comorbidities, indicating metabolism and inflammation may be the links between HF and comorbidities. In this review, we comprehensively discuss the major underlying mechanisms and therapeutic implications for comorbidities of HF. We first summarize the potential role of metabolism and inflammation in HF. Then, we give an overview of the linkage between common comorbidities and HF, from the perspective of epidemiological evidence to the underlying metabolism and inflammation mechanisms. Moreover, with the help of bioinformatics, we summarize the shared risk factors, signal pathways, and therapeutic targets between HF and comorbidities. Metabolic syndrome, aging, deleterious lifestyles (sedentary behavior, poor dietary patterns, smoking, etc.), and other risk factors common to HF and comorbidities are all associated with common mechanisms. Impaired mitochondrial biogenesis, autophagy, insulin resistance, and oxidative stress, are among the major mechanisms of both HF and comorbidities. Gene enrichment analysis showed the PI3K/AKT pathway may probably play a central role in multi morbidity. Additionally, drug targets common to HF and several common comorbidities were found by network analysis. Such analysis has already been instrumental in drug repurposing to treat HF and comorbidity. And the result suggests sodium-glucose transporter-2 (SGLT-2) inhibitors, IL-1β inhibitors, and metformin may be promising drugs for repurposing to treat multi morbidity. We propose that targeting the metabolic and inflammatory pathways that are common to HF and comorbidities may provide a promising therapeutic strategy.

Obesity cardiomyopathy: evidence, mechanisms, and therapeutic implications

The prevalence of heart failure is on the rise and imposes a major health threat, in part, due to the rapidly increased prevalence of overweight and obesity. To this point, epidemiological, clinical, and experimental evidence supports the existence of a unique disease entity termed “obesity cardiomyopathy,” which develops independent of hypertension, coronary heart disease, and other heart diseases. Our contemporary review evaluates the evidence for this pathological condition, examines putative responsible mechanisms, and discusses therapeutic options for this disorder. Clinical findings have consolidated the presence of left ventricular dysfunction in obesity. Experimental investigations have uncovered pathophysiological changes in myocardial structure and function in genetically predisposed and diet-induced obesity. Indeed, contemporary evidence consolidates a wide array of cellular and molecular mechanisms underlying the etiology of obesity cardiomyopathy including adipose tissue dysfunction, systemic inflammation, metabolic disturbances (insulin resistance, abnormal glucose transport, spillover of free fatty acids, lipotoxicity, and amino acid derangement), altered intracellular especially mitochondrial Ca²⁺ homeostasis, oxidative stress, autophagy/mitophagy defect, myocardial fibrosis, dampened coronary flow reserve, coronary microvascular disease (microangiopathy), and endothelial impairment. Given the important role of obesity in the increased risk of heart failure, especially that with preserved systolic function and the recent rises in COVID-19-associated cardiovascular mortality, this review should provide compelling evidence for the presence of obesity cardiomyopathy, independent of various comorbid conditions, underlying mechanisms, and offer new insights into potential therapeutic approaches (pharmacological and lifestyle modification) for the clinical management of obesity cardiomyopathy.

Adiponectin Synthesis, Secretion and Extravasation from Circulation to Interstitial Space

Adiponectin, an adipokine that circulates as multiple multimeric complexes at high levels in serum, has antidiabetic, anti-inflammatory, antiatherogenic, and cardioprotective properties. Understanding the mechanisms regulating adiponectin's physiological effects is likely to provide critical insight into the development of adiponectin-based therapeutics to treat various metabolic-related diseases. In this review, we summarize our current understanding on adiponectin action in its various target tissues and in cellular models. We also focus on recent advances in two particular regulatory aspects; namely, the regulation of adiponectin gene expression, multimerization, and secretion, as well as extravasation of circulating adiponectin to the interstitial space and its degradation. Finally, we discuss some potential therapeutic approaches using adiponectin as a target and the current challenges facing adiponectin-based therapeutic interventions.

The Effects of Laparoscopic Sleeve Gastrectomy on Cardiac Diastolic Function, Aortic Elasticity, and Atrial Electromechanics Delay

BACKGROUND

Obesity is a well-known risk factor for cardiovascular diseases. The aim of this study was to prospectively investigate the short-term effects of laparoscopic sleeve gastrectomy (LSG) on cardiac functions.

METHODS

Forty-four morbidly obese patients who underwent LSG were included in the study. The aortic systolic and diastolic diameters, left ventricular (LV) diameter, LV cardiac output and cardiac index, LV ejection fraction, LV septal and lateral wall velocities, deceleration time of the E wave, the LA volume index and atrial mechanic functions, and atrial conduction times were evaluated.

RESULTS

The patients' aortic stiffness index showed a significant improvement at postoperative control: 3.23 ± 0.58, 2.49 ± 0.36; p<0.001 for preoperative and postoperative aortic stiffness index, respectively. A significant reduction was observed in the LV mass and relative wall thickness (RWT) of the patients: 182.41 ± 36.87 g, 154.85 ± 24.32 g; p<0.001 and 0.42 ± 0.07, 0.39 ± 0.05; p=0.010 for the preoperative and postoperative LV mass and RWT, respectively. A statistically significant decrease was observed in total atrial conduction time and interatrial and intraatrial conduction time in the postoperative period: 120.95 ± 22.27 ms, 106.57 ± 20.46 ms; p=0.001; 13.82 ± 8.21 ms, 10.66 ± 6.78 ms; p=0.038, and 29.64 ± 14.18 ms, 24.09 ± 10.95 ms; p=0.047 for preoperative and postoperative total atrial conduction time, intraatrial electromechanical delay, and interatrial electromechanical delay, respectively.

CONCLUSIONS

Weight loss reduced aortic stiffness, IVS and posterior wall thickness, LAV, LAVi, LA passive emptying fraction, and atrial electromechanical delays in morbidly obese patients.

Influence of cardiometabolic comorbidities on myocardial function, infarction, and cardioprotection: Role of cardiac redox signaling

The morbidity and mortality from cardiovascular diseases (CVD) remain high. Metabolic diseases such as obesity, hyperlipidemia, diabetes mellitus (DM), non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) as well as hypertension are the most common comorbidities in patients with CVD. These comorbidities result in increased myocardial oxidative stress, mainly from increased activity of nicotinamide adenine dinucleotide phosphate oxidases, uncoupled endothelial nitric oxide synthase, mitochondria as well as downregulation of antioxidant defense systems. Oxidative and nitrosative stress play an important role in ischemia/reperfusion injury and may account for increased susceptibility of the myocardium to infarction and myocardial dysfunction in the presence of the comorbidities. Thus, while early reperfusion represents the most favorable therapeutic strategy to prevent ischemia/reperfusion injury, redox therapeutic strategies may provide additive benefits, especially in patients with heart failure. While oxidative and nitrosative stress are harmful, controlled release of reactive oxygen species is however important for cardioprotective signaling. In this review we summarize the current data on the effect of hypertension and major cardiometabolic comorbidities such as obesity, hyperlipidemia, DM, NAFLD/NASH on cardiac redox homeostasis as well as on ischemia/reperfusion injury and cardioprotection. We also review and discuss the therapeutic interventions that may restore the redox imbalance in the diseased myocardium in the presence of these comorbidities.

Relationship between extreme obesity and mortality in patients with reduced ejection fraction

AIMS

Although obesity is associated with increased mortality, epidemiologic studies in heart failure have reported lower mortality in obese patients compared with matched nonobese patients (the 'obesity paradox'). However, the relationship between survival and extreme (morbid) obesity (BMI ≥ 40) is poorly understood. We evaluate survival in low ejection fraction patients across a range of BMI categories, including extreme obesity.

METHODS

In a retrospective review, 12 181 consecutive patients receiving nuclear stress testing at a tertiary care center were stratified based on BMI and ejection fraction. Eight-year mortality data were collected using the social security death index.

RESULTS

Normal ejection fraction patients (internal control, ejection fraction ≥50%) exhibited the J-shaped association between mortality and BMI that is observed in the general population. Among patients with reduced ejection fraction (<50%), survival improved as obesity increased (P < 0.0001). Those with extreme obesity had the lowest mortality (n = 1134, P < 0.05).

CONCLUSION

In this cohort of reduced Ejection fraction patients, the obesity paradox was observed in all weight categories, with the highest survival of all observed in the extremely obese BMI category. This further supports hypotheses that an obesity-related physiologic phenomenon affects mortality in reduced ejection fraction patients.

Does bariatric surgery improve cardiac autonomic modulation assessed by heart rate variability? A systematic review

Our study aimed to explore the influence of bariatric surgery (BS) on heart rate (HR) variability (HRV) through a systematic review. Manuscripts were selected based on electronic searches of the MEDLINE, EMBASE, and CINAHL databases from the inception of each database up to year 2020, and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Searching of these studies was systematized using the Population Intervention Comparison Outcome Study Design strategy. We selected randomized and nonrandomized controlled trials and cohorts from prospective studies that reported the influence of BS on HRV. We assessed the quality rating using the Black and Downs questionnaire. Following the screening and eligibility stages, 14 studies were included in the review. All studies agreed that BS promotes an increase in parasympathetic HR control and HRV and a decrease in HR. Yet the literature does not provide evidence that these outcomes are directly caused by the surgical procedure. There is limited evidence to support that patients with type 2 diabetes have greater improvement in HRV as an interim measure, to individuals without. The decrease in insulin resistance was correlated with the increase in HRV in some studies, but, other studies are unsupportive of this outcome. Improvements in 2 metabolic parameters (e.g., leptin, N-terminal pro B-type natriuretic peptide) were connected with superior increases in HRV. This review demonstrated that BS promotes an increase in HRV, indicating improved autonomic control of HR.

Molecular Mechanisms of Obesity-Linked Cardiac Dysfunction: An Up-Date on Current Knowledge

Obesity is defined as excessive body fat accumulation, and worldwide obesity has nearly tripled since 1975. Excess of free fatty acids (FFAs) and triglycerides in obese individuals promote ectopic lipid accumulation in the liver, skeletal muscle tissue, and heart, among others, inducing insulin resistance, hypertension, metabolic syndrome, type 2 diabetes (T2D), atherosclerosis, and cardiovascular disease (CVD). These diseases are promoted by visceral white adipocyte tissue (WAT) dysfunction through an increase in pro-inflammatory adipokines, oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and adverse changes in the gut microbiome. In the heart, obesity and T2D induce changes in substrate utilization, tissue metabolism, oxidative stress, and inflammation, leading to myocardial fibrosis and ultimately cardiac dysfunction. Peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of carbohydrate and lipid metabolism, also improve insulin sensitivity, triglyceride levels, inflammation, and oxidative stress. The purpose of this review is to provide an update on the molecular mechanisms involved in obesity-linked CVD pathophysiology, considering pro-inflammatory cytokines, adipokines, and hormones, as well as the role of oxidative stress, inflammation, and PPARs. In addition, cell lines and animal models, biomarkers, gut microbiota dysbiosis, epigenetic modifications, and current therapeutic treatments in CVD associated with obesity are outlined in this paper.

Cardiovascular Imaging in Obesity

Obesity represents one of the most challenging public health problems of our century. It accounts for approximately 5% of deaths worldwide, mostly owing to cardiovascular disease and its associated complications. Cardiovascular noninvasive imaging may provide early accurate information about hypertrophy and ischemia/fibrosis in obese subjects. Echocardiography and nuclear cardiology have serious limitations in obese subjects owing to poor acoustic window and attenuation artifacts, respectively. Coronary computed tomography angiography can provide information about obstructive coronary disease; however, the use of radiation is a serious disadvantage. Finally, cardiac magnetic resonance (CMR) holds the promise of an "all in one" examination by combining evaluation of function, wall motion/thickness, stress rest/perfusion, replacement and diffuse fibrosis without radiation. Future studies are required to document the cost/benefit ratio of the CMR in the evaluation of cardiovascular risk in overweight/obese children and adolescents.

Effects of Green Banana Biomass (Musa spp.) on Laboratory Parameters of Animal Models of Wistar Mice under Hyperlipidic Diet

AIM

Analyze the effects of green banana biomass (Musa spp.) on the biochemical parameters in Wistar male rats under standard and hyperlipidic diet.

METHODS

Ethical approval for this study was obtained from Ethics Committee on the Use of Animals CEUA - PUC-GO and consisted in the division of 32 rats in 4 differentiated groups according to their diet (standard - CT; standard with green banana biomass - CTBM; hyperlipidic - HL and hyperlipidic with green banana biomass - HLBM). Through 8 weeks animals were weighted and their glycemia were measured. After this period, they were euthanized and biological material was collected to evaluate the biochemical parameters, which analysis used the ANOVA test.

RESULTS

The weekly evaluation confirmed that the efficacy of the hyperlipidic model since the final weight was bigger in the HL group in comparison with the CT group, from the sixth to the eighth week. It was also possible to observe that the CTBM group had a smaller weight compared to the CT group. Besides, the measurement of glycemia, high-density lipoprotein, triglycerides, alanine aminotransferase, aspartate aminotransferase, serum total bilirubin, direct bilirubin, alkaline phosphatase, urea, serum creatine, uric acid, calcium, phosphor, magnesium and the hematological parameters from the 8 animal of each group were compared by the ANOVA test without any significative difference (p < 0.05) in the comparisons.

CONCLUSIONS

This study it did not demonstrate significative changes of the green banana biomass on the observed laboratory parameters during the 8 weeks in comparison to the standard group, indicating an absence of interference of the probiotics in the laboratory parameters on the hyperlipidic model during the analyzed period. Therefore, it is necessary an evaluation of its efficacy in obesity treatment in longer studies with molecular parameters.

Anti-IL-20 Antibody Protects against Ischemia/Reperfusion-Impaired Myocardial Function through Modulation of Oxidative Injuries, Inflammation and Cardiac Remodeling

Acute myocardial infarction (AMI) is the most critical event in the disease spectrum of coronary artery disease. To rescue cardiomyocytes in AMI, it is important to restore blood supply as soon as possible to reduce ischemia-induced injury. However, worse damage can occur during the reperfusion phase, called the reperfusion injury. Under ischemia/reperfusion (I/R) injury, elevated oxidative stress plays a critical role in regulation of apoptosis, inflammation and remodeling of myocardium. Our previous study has demonstrated that interleukin (IL)-20 is increased during hypoxia/reoxygenation stimulation and promotes apoptosis in cardiomyocytes. This study was, therefore, designed to investigate whether IL-20 antibody could reduce I/R-induced myocardial dysfunction. Results from this study revealed that IL-20 antibody treatment significantly suppressed I/R-induced nicotinamide adenine dinucleotide phosphate oxidase, oxidative stress, apoptosis, proinflammatory responses, cardiac fibrosis, and expression of cardiac remodeling markers in Sprague-Dawley rats. Plasma B-type natriuretic peptide level was also reduced by IL-20 antibody injection. IL-20 antibody treatment appeared to restore cardiac function under the I/R injury in terms of greater values of ejection fraction and fractional shortening compared to the control group. Two commonly used indicators of cardiac injury, lactate dehydrogenase and creatine kinase-MB, were also lower in the IL-20 antibody injection group. Taken together, our results suggested that IL-20 antibody holds the potential to reduce the I/R-elicited cardiac dysfunction by preventing cardiac remodeling.

The Role of Obesity in the Development and Management of Gynecologic Cancer

Importance

Endometrial cancer is the most common gynecologic malignancy, with an estimated 54,000 new cases and 10,000 deaths in the United States in 2015. The obesity epidemic directly contributes to the escalating prevalence of chronic diseases, including obesity-related cancers. Patient body weight and nutritional status markedly impact perioperative oncologic care, chemotherapy administration, recurrence risk, and survivorship goals.

Objectives

The objective of this review is to explore the association between obesity and the development, treatment, and survival outcomes of gynecologic cancers.

Evidence Acquisition

A systematic literature review was performed utilizing PubMed and ClinicalTrials.gov.

Conclusions and Relevance

Caring for obese women with gynecologic cancers presents unique challenges. A coordinated multidisciplinary and system effort is required to address the prevention and treatment of obesity, as the sequela of this disease is a clear risk factor for the development of gynecologic malignancy and other comorbidities. Health care providers must be ready to address this worldwide health problem.

Left ventricular myocardial oxygen demand and subclinical dysfunction in patients with severe obesity referred for bariatric surgery

BACKGROUND AND AIMS

Increased myocardial oxygen (O₂) demand carries higher cardiovascular risk in hypertension. We hypothesized that myocardial O₂ demand is increased in severe obesity and linked to early left ventricular (LV) dysfunction.

METHODS AND RESULTS

Baseline data from 106 severely obese subjects referred for gastric bypass surgery (42 ± 11 years, 74% women, body mass index [BMI] 41.9 ± 4.8 kg/m², 32% with hypertension) in the prospective FatWest (Bariatric Surgery on the West Coast of Norway) study was used. LV systolic function was assessed by biplane ejection fraction (EF), midwall shortening (MWS) and endocardial global longitudinal strain (GLS), and LV diastolic function by mitral annular early diastolic velocity (e'). Myocardial O₂ demand was estimated from the LV mass-wall stress-heart rate product (high if > 1.62 × 10⁶/2.29 × 10⁶ g kdyne/cm² bpm in women/men). High myocardial O₂ demand was found in 33% and associated with higher BMI and high prevalence of low GLS (65%) and low MWS (63%) despite normal EF. In ROC analyses, higher myocardial O₂ demand discriminated between patients with low vs. normal MWS and GLS (area under curve 0.71 and 0.63, p < 0.05). In successive multiple regression analyses, higher myocardial O₂ demand was associated with lower LV MWS, GLS and average e', respectively, independent of age, gender, BMI, pulse pressure, diabetes mellitus, and EF (all p < 0.05).

CONCLUSION

In obese patients without known heart disease and with normal EF referred for bariatric surgery, high myocardial O₂ demand is associated with lower myocardial function whether assessed by GLS or MWS independent of confounders. CLINICALTRIALS.

GOV IDENTIFIER

NCT01533142.

Favorable electrocardiographic changes after substantial weight loss in patients with morbid obesity : Results of a prospective study

BACKGROUND

Obese patients have an increased risk of arrhythmias and sudden death, even in the absence of structural heart disease and cardiac dysfunction. This study aimed to determine whether weight loss by bariatric surgery has an effect on arrhythmia-related electrocardiographic (ECG) variables in morbidly obese patients.

METHODS

In this prospective study, the data of 48 patients were analyzed. All ECG variables that have the potential to predict ventricular arrhythmia were evaluated before surgery, and were compared with the 1‑month and 6‑month follow-up results.

RESULTS

The mean body mass index was 45.74 ± 5.60 kg/m² before surgery. There was a statistically significant decline in body mass index in the first and sixth month after surgery (39.26 ± 5.00 kg/m² and 31.71 ± 4.49 kg/m², respectively; p < 0.001). Furthermore, notable reduction was found in terms of heart rate measurements-QTc‑d, JTc, JTc‑d, Tp‑e, TP-e/QT, TP-e/QTc-in the first month and sixth month compared with baseline (p < 0.001 for all comparisons). Several ECG variables, such as heart rate (r = 0.369, p = 0.001), QTc‑d (r = 0.449, p = 0.001), JTc‑d (r = 0.324, p = 0.002), Tp‑e (r = 0.592, p = 0.001), Tp-e/QTc (r = 0.543, p = 0.001), Tp-e/JTc (r = 0.515, p = 0.001), exhibited a positive and significant correlation with weigh loss. Moreover, a negative and weakly significant correlation was found between the index of cardiac electrophysiological balance (r = -0.239, p = 0.004) and body mass index.

CONCLUSION

Substantial weight loss following laparoscopic sleeve gastrectomy in obese patients is accompanied by a significant improvement in ventricular repolarization. Therefore, this effect may lead to a decrease in the incidence of lethal ventricular arrhythmia and sudden cardiac death.

Effects of Caloric Restriction Diet on Arterial Hypertension and Endothelial Dysfunction

The most common manifestation of cardiovascular (CV) diseases is the presence of arterial hypertension (AH), which impacts on endothelial dysfunction. CV risk is associated with high values of systolic and diastolic blood pressure and depends on the presence of risk factors, both modifiable and not modifiable, such as overweight, obesity, physical exercise, smoking, age, family history, and gender. The main target organs affected by AH are the heart, brain, vessels, kidneys, and eye retina. AH onset can be counteracted or delayed by adopting a proper diet, characterized by a low saturated fat and sodium intake, a high fruit and vegetable intake, a moderate alcohol consumption, and achieving and maintaining over time the ideal body weight. In this review, we analyzed how a new nutritional approach, named caloric restriction diet (CRD), can provide a significant reduction in blood pressure values and an improvement of the endothelial dysfunction. In fact, CRD is able to counteract aging and delay the onset of CV and neurodegenerative diseases through the reduction of body fat mass, systolic and diastolic values, free radicals production, and oxidative stress. Currently, there are few studies on CRD effects in the long term, and it would be advisable to perform observational studies with longer follow-up.

Inhibition of MyD88 by LM8 Attenuates Obesity-Induced Cardiac Injury

Obesity-induced cardiomyopathy involves chronic and sustained inflammation. The toll-like receptor 4 (TLR4) signaling pathway can associate innate immunity with obesity. Myeloid differentiation primary response 88 (MyD88), an indispensable downstream adaptor molecule of TLR4, has been reported to mediate obesity complications. However, whether inhibition of MyD88 can mitigate obesity-induced heart injury remains unclear. LM8, a new MyD88 inhibitor, exhibits prominent anti-inflammatory activity in lipopolysaccharide-treated macrophages. In this study, the protective effects of LM8 on a high-fat diet (HFD)-induced heart injury were assessed in a mouse model of obesity. As suggested from the achieved results, LM8 treatment alleviated HFD-induced pathological and functional damages of the heart in mice. Meantime, the treatment of mice with LM8 could significantly inhibit myocardial hypertrophy, fibrosis, inflammatory cytokines expression, and inflammatory cell infiltration induced by HFD. Besides, LM8 administration inhibited the formation of MyD88/TLR4 complex, phosphorylation of ERK, and activation of nuclear factor-κB induced by HFD. According to the achieved results, MyD88 inhibitor LM8 ameliorated obesity-induced heart injury by inhibiting MyD88-ERK/nuclear factor-κB dependent cardiac inflammatory pathways. Furthermore, targeting MyD88 might be a candidate of a therapeutic method to treat obesity-induced heart injury.

Morphometric Characterization of Human Coronary Veins and Subvenous Epicardial Adipose Tissue-Implications for Cardiac Resynchronization Therapy Leads

Subvenous epicardial fat tissue (SEAT), which acts as an electrical insulation, and the venous diameter (VD) both constitute histomorphological challenges for optimal application and lead design in cardiac synchronization therapy (CRT). In this study, we characterized the morphology of human coronary veins to improve the technical design of future CRT systems and to optimize the application of CRT leads. We retrospectively analyzed data from cardiac computed tomography (CT) of 53 patients and did studies of 14 human hearts using the postmortem freeze section technique and micro CT. Morphometric parameters (tributary distances, offspring angles, luminal VD, and SEAT thickness) were assessed. The left posterior ventricular vein (VVSP) had a mean proximal VD of 4.0 ± 1.4 mm, the left marginal vein (VMS) of 3.2 ± 1.5 mm and the anterior interventricular vein (VIA) of 3.9 ± 1.3 mm. More distally (5 cm), VDs decreased to 2.4 ± 0.6 mm, 2.3 ± 0.7 mm, and 2.4 ± 0.6 mm, respectively. In their proximal portions (15 mm), veins possessed mean SEAT thicknesses of 3.2 ± 2.4 (VVSP), 3.4 ± 2.4 mm (VMS), and 4.2 ± 2.8 mm (VIA), respectively. More distally (20-70 mm), mean SEAT thicknesses decreased to alternating low levels of 1.3 ± 1.1 mm (VVSP), 1.7 ± 1.1 mm (VMS), and 4.3 ± 2.6 mm (VIA), respectively. In contrast to the VD, SEAT thicknesses alternated along the further distal vein course and did not display a continuous decrease. Besides the CRT responsiveness of different areas of the LV myocardium, SEAT is a relevant electrophysiological factor in CRT, potentially interfering with sensing and pacing. A sufficient VD is crucial for successful CRT lead placement. Measurements revealed a trend toward greater SEAT thickness for the VIA compared to VVSP and VMS, suggesting a superior signal-to-noise-ratio in VVSP and VMS.

Utility of Three Adiposity Indices for Identifying Left Ventricular Hypertrophy and Geometric Remodeling in Chinese Children

BACKGROUND

Previous studies have shown that waist-to-height ratio (WHtR) performed similarly well when compared to body mass index (BMI) and waist circumference (WC) for identifying cardiovascular risk factors. However, to our knowledge, the performance of these three adiposity indices for identifying left ventricular hypertrophy (LVH) and left ventricular geometric (LVG) remodeling in youth has not been assessed. We aimed to determine the utility of BMI, WC and WHtR for identifying LVH and LVG in Chinese children.

METHODS

This study included 1,492 Chinese children aged 6-11 years. Adiposity indices assessed were BMI, WC and WHtR. LVH and high relative wall thickness (RWT) were defined using sex- and age-specific 90th percentile values of left ventricular mass index and RWT, respectively, based on the current population. LVG remodeling included concentric remodeling (CR), eccentric hypertrophy (EH) and concentric hypertrophy (CH), which was defined based on the combination of LVH and high RWT.

RESULTS

The magnitude of association of central obesity defined by WHtR with LVH [odds ratio (OR) =10.09, 95% confidence interval (CI) =6.66-15.29] was similar with general obesity defined by BMI (OR=10.49, 95% CI=6.97-15.80), and both were higher than central obesity defined by WC (OR=6.87, 95% CI=4.57-10.33). Compared with BMI, WHtR had better or similar predictive utility for identifying LVH, EH, and CH [the area under the curve (AUC): 0.84 vs. 0.79; 0.84 vs. 0.77; 0.87 vs. 0.88, respectively]; WC had worse or similar discriminatory utility with AUCs of 0.73, 0.70, 0.83, respectively.

CONCLUSION

WHtR performed similarly or better than BMI or WC for identifying LVH and LVG remodeling among Chinese children. WHtR provides a simple and convenient measure of central obesity that might improve the discrimination of children with cardiac structural damage.

APPLICATION OF QUERCETIN FOR CORRECTION OF THE IMPAIRMENT OF THE FUNCTIONAL STATE OF THE ENDOTHELIUS OF VESSELS (CLINICAL AND EXPERIMENTAL STUDY)

OBJECTIVE

in the experiment, to investigate the effect of Quercetin on the NO-dependent reactions of isolated vessels involving endothelium and perivascular adipose tissue (PVAT) after a single X-ray irradiation of rats at a sublethal dose. In a clinical study, to investigate the effect of long-term use of Quercetin on the functional state of themicrovascular endothelium in the elderly patients with metabolic syndrome (MS).

MATERIAL AND METHODS

Experimental studies were performed on vascular fragments obtained from adult male rats(7-8 months) of the control group, in animals exposed to a single R-irradiation at a dose of 7 Gy and animals irradiated in the same dose, which received Quercetin orally for 14 days three times a week based on 10 mg/kg bodyweight. Fragments of the thoracic aorta (TA) and mesenteric artery (MA) were cleaned of perivascular adipose tissue (PVAT-) or left uncleaned (PVAT+), and then were cut into rings (up to 2 mm). The amplitude of the contractionof the rings TA and MA under the influence of phenylephrine (PE, 3 x 10-6 M), the amplitude of the contraction of therings TA and MA in the presence of a competitive blocker of NO-synthase methyl ester of N-nitro-L-arginine(L-NAME, 10-5 M), the amplitude of relaxation of the rings TA and MA in the presence of N-acetylcysteine (NAC, 10-4 M)were measured. The clinical study examined 110 patients with MS criteria in accordance with ATP III (2001).Patients in the main group for 3 months received Quercetin from the same manufacturer, 80 mg three times a day,patients in the control group received placebo.

RESULTS

Single R-irradiation disrupts the regulation of the contractile function of TA and MA, which is evidenced bychanges in the contractile reactions of isolated fragments of these vessels as a response to the action of vasoactivecompounds. Course use of Quercetin in irradiated rats leads to the normalization of contractile and dilatory vascular responses due to partial correction of NO metabolism in the endothelium and PVAT. For the majority of patients(69 %) who received Quercetin, a post-occlusive hyperemia test showed a statistically significant increase of maximal volumetric velocity of the skin blood flow rate and duration of the recovery period to the baseline, which indicates about improvement of vasomotor vascular endothelial function.

CONCLUSIONS

Course use of Quercetin improves the functional state of the microvascular endothelium among theelderly people with MS, normalizes contractile and dilatory vascular responses in irradiated rats due to partial correction of NO metabolism in the endothelium and PVAT.

Assessment of Intramyocardial Fat Content Using Computed Tomography: Is There a Relationship With Obesity?

BACKGROUND

Fat deposition in the liver and the skeletal muscle are linked to cardiovascular risk factors. Fat content in tissues can be estimated by measuring attenuation on noncontrast computed tomography (CT). Quantifying intramyocardial fat content is of interest as it may be related to myocardial dysfunction or development of heart failure. We hypothesized that myocardial fat content would correlate with severity of obesity, liver fat, and components of the metabolic syndrome.

METHODS

We measured attenuation values on 121 noncontrast CT scans from the spleen, liver, erector spinae muscle, and myocardial septum. A chart review was performed for patient demographics and clinical characteristics. We tested for correlations between attenuation values in each of the tissues and various clinical parameters.

RESULTS

We studied 78 females and 43 males, with a mean age of 54.5±11.2 years. Weak, but significant inverse Spearman correlation between body mass index and attenuation values were found in the liver (ρ=-0.228, P=0.012), spleen (ρ=-0.225, P=0.017), and erector spinae muscle (ρ=-0.211, P=0.022) but not in the myocardial septum (ρ=0.012, P=0.897). Mean attenuation in the nonobese group versus obese group (body mass index >30 kg/m2) were 41.1±5.0 versus 42.3±6.9 (P=0.270) in myocardial septum, 56.1±8.7 versus 51.7±10.9 (P=0.016) in the liver, 43.9±8.9 versus 40.1±10.4 (P=0.043) in the spleen, and 41.7±8.3 versus 39.0±8.8 (P=0.087) in the erector spinae muscle.

CONCLUSIONS

Although CT is a theoretically appealing modality to assess fat content of the myocardium, we did not find a relationship between myocardial CT attenuation and obesity, or other cardiovascular risk factors. These findings suggest that the degree of myocardial fat accumulation in obesity or metabolic syndrome is too small to be detected with this modality.

Effect of bariatric surgery on cardiac structure and function in obese patients: Role of the renin-angiotensin system

Echocardiographic alterations have been described in obesity, but their modifications after bariatric surgery (BS) and mechanisms are little known, mostly in normotensive patients. We aimed to analyze cardiac changes 1 year post‐BS and to explore possible mechanisms. A cohort of patients with severe obesity (58% normotensives) were prospectively recruited and examined before surgery and after 12 months. Clinical and echocardiographic data, 24 h BP, renin‐angiotensin‐aldosterone system (RAAS) components, cytokines, and inflammatory markers were analyzed at these two time points. Overall reduction in body weight was mean (IQR) = 30.0% (25.9–33.8). There were statistically significant decreases in left ventricle mass index^2.7(LVMI)^2.7, septum thickness (ST), posterior wall thickness (PWT), relative wall thickness (RWT), and E/e’, both in the whole cohort and in patients without RAAS blockers (p ≤ .04 for all). Plasma renin activity (PRA) decreased from (median, IQR) = 0.8 (0.3;1.35) to 0.4 (0.2;0.93) ng/ml/h, plasma aldosterone from 92 (58.6;126) to 68.1 (56.2;83.4) ng/dl, and angiotensin‐converting enzyme (ACE)‐2 activity from 7.7 (5.7;11.8) to 6.8 (5.3;11.2) RFU/µl/h, p < .05. The body weight loss correlated with a decrease in both 24 h SBP and 24 h DBP (Pearson's coefficient 0.353, p = .022 and 0.384, p = .012, respectively). Variation (Δ) of body weight correlated with ΔE/e’ (Pearson's coeff. 0.414, p = .008) and with Δ lateral e’ (Pearson's coeff. = −0.363, p = .018). Generalized linear models showed that ΔPRA was an independent variable for the final (12‐months post‐BS) LVMI^2.7 (p = .028). No other changes in cardiac parameters correlated with ΔBP. In addition to the respective baseline value, final values of PWT and RWT were dependent on 12‐month Δ of PRA, ACE, and ACE/ACE2 (p < .03 for all). We conclude that there are cardiac changes post‐BS in patients with severe obesity, normotensives included. Structural changes appear to be related to modifications in the renin‐angiotensin axis.

NLRP3 inflammasome deficiency attenuates metabolic disturbances involving alterations in the gut microbial profile in mice exposed to high fat diet

Obesity-related diseases (e.g. type 2 diabetes mellitus and cardiovascular disorders) represent an increasing health problem worldwide. NLRP3 inflammasome activation may underlie obesity-induced inflammation and insulin resistance, and NLRP3 deficient mice exposed to high fat diet (HFD) appear to be protected from left ventricle (LV) concentric remodeling. Herein, we investigated if these beneficial effects were associated with alterations in plasma metabolites, using metabolomic and lipidomic analysis, and gut microbiota composition, using 16S rRNA sequencing of cecum content, comparing NLRP3 deficient and wild type (WT) mice on HFD and control diet. Obese NLRP3 deficient mice had lower systemic ceramide levels, potentially resulting attenuating inflammation, altered hepatic expression of fatty acids (FA) with lower mono-saturated FA and higher polyunsaturated FA levels, potentially counteracting development of liver steatosis, downregulated myocardial energy metabolism as assessed by proteomic analyses of LV heart tissue, and different levels of bile acids as compared with WT mice. These changes were accompanied by an altered composition of gut microbiota associated with decreased systemic levels of tri-methylamine-N-oxide and lipopolysaccharide, potentially inducing attenuating systemic inflammation and beneficial effects on lipid metabolism. Our findings support a role of NLRP3 inflammasome in the interface between metabolic and inflammatory stress, involving an altered gut microbiota composition.

Feasibility of weight loss in obese atrial fibrillation patients attending a specialist arrhythmia clinic and its impact on ablation outcomes

BACKGROUND

The feasibility of significant weight reduction in a specialist arrhythmia service, and its impact on atrial fibrillation (AF) ablation outcomes are unclear. We aimed to assess these factors in a real-world cohort in the United Kingdom.

METHODS

Patients from one specialized arrhythmia clinic were instructed to follow the "Intermittent Fasting 5:2 diet" ("diet group", n = 50), and their outcomes were compared to a propensity matched cohort who received no specific dietary advice ("control group", n = 42). The primary outcome was recurrence of AF or atrial tachycardia (AT) at 12 months postablation, with or without drugs.

RESULTS

Body weight and body mass index (BMI) at baseline were 105.0 (±15.3) kgs and 36.0 (±4.0), respectively. Baseline characteristics between the two groups were comparable. Patients in diet group experienced a mean weight loss of 8.2 (±7.1) kgs prior to AF ablation (P < .01 for comparison to baseline and control group). About 14 (28%) patients in the diet group lost >10% of their body weight. Overall, 11 (22%) patients in the diet group and five (12%) in the control group had AF recurrence at 1 year, P = .21. AF recurrence was similar in patients with BMI ≥ 35 (15%) as compared to BMI < 35 (19%), P = .60. There was one procedural complication (pulmonary edema) in the diet group.

CONCLUSION

It is feasible to achieve significant weight reduction in obese AF patients in a specialist arrhythmia clinic setting with unsupervised dietary advice. Low rates of procedural complications and excellent medium-term success rates were observed in this traditionally challenging population. Additional improvements in outcomes were not demonstrable in patients who exhibited significant weight loss.

The Pivotal Role of Adipocyte-Na K peptide in Reversing Systemic Inflammation in Obesity and COVID-19 in the Development of Heart Failure

This review summarizes data from several laboratories that have demonstrated a role of the Na/K-ATPase, specifically its α1 subunit, in the generation of reactive oxygen species (ROS) via the negative regulator of Src. Together with Src and other signaling proteins, the Na/K-ATPase forms an oxidant amplification loop (NKAL), amplifies ROS, and participates in cytokines storm in obesity. The development of a peptide fragment of the α1 subunit, NaKtide, has been shown to negatively regulate Src. Several groups showed that the systemic administration of the cell permeable modification of NaKtide (pNaKtide) or its selective delivery to fat tissue-adipocyte specific expression of NaKtide-ameliorate the systemic elevation of inflammatory cytokines seen in chronic obesity. Severe acute respiratory syndrome - coronavirus 2 (SARS-CoV-2), the RNA Coronavirus responsible for the COVID-19 global pandemic, invades cells via the angiotensin converting enzyme 2 (ACE-2) receptor (ACE2R) that is appended in inflamed fat tissue and exacerbates the formation of the cytokines storm. Both obesity and heart and renal failure are well known risks for adverse outcomes in patients infected with COVID-19. White adipocytes express ACE-2 receptors in high concentration, especially in obese patients. Once the virus invades the white adipocyte cell, it creates a COVID19-porphyrin complex which degrades and produces free porphyrin and iron and increases ROS. The increased formation of ROS and activation of the NKAL results in a further potentiated formation of ROS production, and ultimately, adipocyte generation of more inflammatory mediators, leading to systemic cytokines storm and heart failure. Moreover, chronic obesity also results in the reduction of antioxidant genes such as heme oxygenase-1 (HO-1), increasing adipocyte susceptibility to ROS and cytokines. It is the systemic inflammation and cytokine storm which is responsible for many of the adverse outcomes seen with COVID-19 infections in obese subjects, leading to heart failure and death. This review will also describe the potential antioxidant drugs and role of NaKtide and their demonstrated antioxidant effect used as a major strategy for improving obesity and epicardial fat mediated heart failure in the context of the COVID pandemic.

Voluntary activity reverses spermidine-induced myocardial fibrosis and lipid accumulation in the obese male mouse

Obesity due to high calorie intake induces cardiac hypertrophy and dysfunction, thus contributing to cardiovascular morbidity and mortality. Recent studies in aging suggest that oral supplementation with the natural polyamine spermidine has a cardioprotective effect. Here, the hypothesis was tested that spermidine or voluntary activity alone or in combination protect the heart from adverse effects induced by obesity. Therefore, C57Bl/6 mice (n = 8–10 per group) were subjected to control or high fat diet (HFD) and were left untreated, or either received spermidine via drinking water or were voluntarily active or both. After 30 weeks, the mice were killed and the left ventricle of the hearts was processed for light and electron microscopy. Design-based stereology was used to estimate parameters of hypertrophy, fibrosis, and lipid accumulation. HFD induced cardiac hypertrophy as demonstrated by higher volumes of the left ventricle, cardiomyocytes, interstitium, myofibrils and cardiomyocyte mitochondria. These changes were not influenced by spermidine or voluntary activity. HFD also induced myocardial fibrosis and accumulation of lipid droplets within cardiomyocytes. These HFD effects were enhanced in spermidine treated animals but not in voluntarily active mice. This was even the case in voluntarily active mice that received spermidine. In conclusion, the data confirm the induction of left ventricular hypertrophy by high-fat diet and suggest that—under high fat diet—spermidine enhances cardiomyocyte lipid accumulation and interstitial fibrosis which is counteracted by voluntary activity.

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.

Obesity related changes in cardiac structure and function: role of blood pressure and metabolic abnormalities

Background: It has been reported that changes in cardiac structure and ventricular function associated with obesity have to be attributable to hemodynamic and non-hemodynamic alterations. Accordingly, the aim of this was to evaluate left ventricular hypertrophy (LVH) prevalence and its effect on left ventricular systolic and diastolic function in a cohort of obese patients.Materials and Methods: LV internal diameter (LVID), left ventricular mass (LVM) and LVM/height^2.7(LVMI), relative wall thickness (RWT), LV ejection fraction (LVEF), E/A ratio, isovolumic relaxation time, deceleration time of E velocity by echocardiography and pulsed-wave Doppler and total circulating adiponectin (ADPN) by radioimmunoassay were measured in 319 obese subjects with and without LVH.Results: Increased values of BMI, WHR, SBP, DBP, MBP LVID, LVM, LVMI, IVST (p < .001), increased prevalence of subjects with LVEF< 50%,(p < .001), central fat distribution (p < .001), hypertension (p < .001), diabetes (p < .001), metabolic syndrome (p < .02), and reduced value of ADPN (p < .0001) and LVEF (p < .001) were detected in LVH obese subjects than controls without LVH. No significant differences in diastolic parameters were observed between the two groups. LVEF correlated directly with ADPN (p < .0001) and inversely with age (p < .01), BMI (p < .01), WHR (p < .001), MBP (p < .01) MetS (p < .02) and LVMI (p < .001). WHR, MBP, LVMI and ADPN were independently associated with LVEF.Conclusions: In conclusion, our data indicate that obese subjects with LVH might be considered a distinct phenotype of obesity, characterised by LVH, increased prevalence of cardiometabolic comorbidities, central fat distribution, hypoadiponectinemia and early left ventricular systolic dysfunction.

Obesity-induced activation of JunD promotes myocardial lipid accumulation and metabolic cardiomyopathy

AIMS

Metabolic cardiomyopathy (MC)-characterized by intra-myocardial triglyceride (TG) accumulation and lipotoxic damage-is an emerging cause of heart failure in obese patients. Yet, its mechanisms remain poorly understood. The Activator Protein 1 (AP-1) member JunD was recently identified as a key modulator of hepatic lipid metabolism in obese mice. The present study investigates the role of JunD in obesity-induced MC.

METHODS AND RESULTS

JunD transcriptional activity was increased in hearts from diet-induced obese (DIO) mice and was associated with myocardial TG accumulation and left ventricular (LV) dysfunction. Obese mice lacking JunD were protected against MC. In DIO hearts, JunD directly binds PPARγ promoter thus enabling transcription of genes involved in TG synthesis, uptake, hydrolysis, and storage (i.e. Fas, Cd36, Lpl, Plin5). Cardiac-specific overexpression of JunD in lean mice led to PPARγ activation, cardiac steatosis, and dysfunction, thereby mimicking the MC phenotype. In DIO hearts as well as in neonatal rat ventricular myocytes exposed to palmitic acid, Ago2 immunoprecipitation, and luciferase assays revealed JunD as a direct target of miR-494-3p. Indeed, miR-494-3p was down-regulated in hearts from obese mice, while its overexpression prevented lipotoxic damage by suppressing JunD/PPARγ signalling. JunD and miR-494-3p were also dysregulated in myocardial specimens from obese patients as compared with non-obese controls, and correlated with myocardial TG content, expression of PPARγ-dependent genes, and echocardiographic indices of LV dysfunction.

CONCLUSION

miR-494-3p/JunD is a novel molecular axis involved in obesity-related MC. These results pave the way for approaches to prevent or treat LV dysfunction in obese patients.

Compound LM9, a novel MyD88 inhibitor, efficiently mitigates inflammatory responses and fibrosis in obesity-induced cardiomyopathy

Mechanisms of cardiomyopathy caused by obesity/hyperlipidemia are complicated. Obesity is usually associated with chronic low-grade inflammation and may lead to the onset and progression of myocardial fibrosis and remodeling. TLR4/MyD88 signaling pathway, as a key regulator of inflammation, plays an important role in the pathogenesis of obesity-induced cardiomyopathy. We previously demonstrated that LM9, a novel MyD88 inhibitor, attenuated inflammatory responses and fibrosis in obesity-induced cardiomyopathy by inhibiting the formation of TLR4/MyD88 complex. In this study, we investigated the protective effects of LM9 on obesity-induced cardiomyopathy in vitro and in vivo. We showed that LM9 (5, 10 μM) significantly attenuates palmitic acid (PA)-induced inflammation in mouse peritoneal macrophages, evidenced by decreased expression of proinflammatory genes including TNF-α, IL-6, IL-1β, and ICAM-1. In cardiac-derived H9C2 cells, LM9 treatment suppressed PA-induced inflammation, lipid accumulation, and fibrotic responses. In addition, LM9 treatment also inhibited PA-activated TLR4/MyD88/NF-κB signaling pathway. We further revealed in HEK293 cells that LM9 treatment blocked the TLR4/MyD88 binding and MyD88 homodimer formation. In HFD-fed mice, administration of LM9 (5, 10 mg/kg, ig, every other days for 8 weeks) dose-dependently alleviated inflammation and fibrosis in heart tissues and decreased serum lipid concentration. In conclusion, this study demonstrates that MyD88 inhibitor LM9 exerts protective effects against obesity-induced cardiomyopathy, suggesting LM9 to be a promising therapeutic candidate drug for the obesity-related cardiac complications.

Brown adipose tissue-derived exosomes mitigate the metabolic syndrome in high fat diet mice

The ever-increasing incidence of obesity and related disorders impose serious challenges on public health worldwide. Brown adipose tissue (BAT) has strong capacity for promoting energy expenditure and has shown great potential in treating obesity. Exosomes are nanovesicles that share the characteristics of their donor cells. Whether BAT derived exosomes (BAT-Exos) might exert similar metabolic benefits on obesity is worthy of investigation. Methods: Obese mice were established by high-fat-diet (HFD) feeding and were treated with Seum-Exos or BAT-Exos isolated from young healthy mice. Blood glucose, glucose tolerance and blood lipids were tested in mice with indicated treatments. Histology examinations were performed on adipose tissue, liver and heart by HE staining and/or Oil Red O staining. Echocardiography was performed to evaluate cardiac function of mice. In vivo distribution of exosomes was analyzed by fluorescence labeling and imaging and in vitro effects of exosomes were evaluated by cell metabolism analysis. Protein contents of BAT-Exos were analyzed by mass spectrometry. Results: The results showed that BAT-Exos reduced the body weight, lowered blood glucose and alleviated lipid accumulation in HFD mice independently of food intake. Echocardiography revealed that the abnormal cardiac functions of HFD mice were significantly restored after treatment with BAT-Exos. Cell metabolism analysis showed that treatment with BAT-Exos significantly promoted oxygen consumption in recipient cells. Protein profiling of exosomes demonstrated that BAT-Exos were rich in mitochondria components and involved in catalytic processes. Conclusions: Collectively, our study showed that BAT-Exos significantly mitigated the metabolic syndrome in HFD mice. Detailed elucidation of the reactive molecules and mechanism of action would provide new insights in combating obesity and related disorders.

Hemodynamic and Functional Impact of Epicardial Adipose Tissue in Heart Failure With Preserved Ejection Fraction

OBJECTIVES

This study determined the impact of excess epicardial adipose tissue (EAT) in patients with the obese phenotype of heart failure with preserved ejection fraction (HFpEF).

BACKGROUND

Patients with HFpEF and an elevated body mass index differ from nonobese patients, but beyond generalized obesity, fat distribution may be more important. Increases in EAT are associated with excess visceral adiposity, inflammation, and cardiac fibrosis, and EAT has been speculated to play an important role in the pathophysiology of HFpEF, but no study has directly evaluated this question.

METHODS

Patients with HFpEF and obesity (n = 169) underwent invasive hemodynamic exercise testing with expired gas analysis and echocardiography. Increased EAT was defined by echocardiography (EAT thickness ≥9 mm).

RESULTS

Compared with obese patients without increased EAT (HFpEF_EAT-, n = 92), obese patients with HFpEF with increased EAT (HFpEF_EAT+; n = 77) displayed a higher left ventricular eccentricity index, indicating increased pericardial restraint, but similar resting biventricular structure and function. In contrast, hemodynamics were more abnormal in patients with HFpEF_EAT+, with higher right atrial, pulmonary artery, and pulmonary capillary wedge pressures at rest and during exercise compared with those of patients with HFpEF_EAT-. Peak oxygen consumption (VO₂) was reduced in both groups but was 20% lower in patients with HFpEF_EAT+ (p < 0.01).

CONCLUSIONS

Among patients with the obese phenotype of HFpEF, the presence of increased EAT is associated with more profound hemodynamic derangements at rest and exercise, including greater elevation in cardiac filling pressures, more severe pulmonary hypertension, and greater pericardial restraint, culminating in poorer exercise capacity. Further study is needed to understand the biology and treatment of excessive EAT in patients with HFpEF.

Human Cardiac Mesenchymal Stromal Cells From Right and Left Ventricles Display Differences in Number, Function, and Transcriptomic Profile

BACKGROUND

Left ventricle (LV) and right ventricle (RV) are characterized by well-known physiological differences, mainly related to their different embryological origin, hemodynamic environment, function, structure, and cellular composition. Nevertheless, scarce information is available about cellular peculiarities between left and right ventricular chambers in physiological and pathological contexts. Cardiac mesenchymal stromal cells (C-MSC) are key cells affecting many functions of the heart. Differential features that distinguish LV from RV C-MSC are still underappreciated.

AIM

To analyze the physiological differential amount, function, and transcriptome of human C-MSC in LV versus (vs.) RV.

METHODS

Human cardiac specimens of LV and RV from healthy donors were used for tissue analysis of C-MSC number, and for C-MSC isolation. Paired LV and RV C-MSC were compared as for surface marker expression, cell proliferation/death ratio, migration, differentiation capabilities, and transcriptome profile.

RESULTS

Histological analysis showed a greater percentage of C-MSC in RV vs. LV tissue. Moreover, a higher C-MSC amount was obtained from RV than from LV after isolation procedures. LV and RV C-MSC are characterized by a similar proportion of surface markers. Functional studies revealed comparable cell growth curves in cells from both ventricles. Conversely, LV C-MSC displayed a higher apoptosis rate and RV C-MSC were characterized by a higher migration speed and collagen deposition. Consistently, transcriptome analysis showed that genes related to apoptosis regulation or extracellular matrix organization and integrins were over-expressed in LV and RV, respectively. Besides, we revealed additional pathways specifically associated with LV or RV C-MSC, including energy metabolism, inflammatory response, cardiac conduction, and pluripotency.

CONCLUSION

Taken together, these results contribute to the functional characterization of RV and LV C-MSC in physiological conditions. This information suggests a possible differential role of the stromal compartment in chamber-specific pathologic scenarios.

Early Growth Patterns and Cardiac Structure and Function at Midlife: Northern Finland 1966 Birth Cohort Study

OBJECTIVES

To evaluate the influence of early growth patterns that have previously been associated with later cardiometabolic risk on cardiac left ventricular (LV) structure and function in midlife.

STUDY DESIGN

A subpopulation of the Northern Finland Birth Cohort 1966 took part in follow-up, including echocardiography (n = 1155) at the age of 46 years. Body mass index (BMI) growth curves were modeled based on frequent anthropometric measurements in childhood. Age and BMI at adiposity peak (n = 482, mean age 9.0 months) and at adiposity rebound (n = 586, mean age 5.8 years) were determined. Results are reported as unstandardized beta (β) or OR with 95% CIs for 1 SD increase in early growth variable.

RESULTS

Earlier adiposity rebound was associated with increased LV mass index (β = -4.10 g/m² (-6.9, -1.3); P = .004) and LV end-diastolic volume index (β = -2.36 mL/m² (-3.9, -0.84); P = .002) as well as with eccentric LV hypertrophy (OR 0.54 [0.38, 0.77]; P = .001) in adulthood in males. BMI at adiposity rebound was directly associated with LV mass index (β = 2.33 g/m² [0.80, 3.9]; P = .003). Higher BMI at both adiposity peak and at adiposity rebound were associated with greater LV end-diastolic volume index (β = 1.47 mL/m²; [0.51, 2.4], β = 1.28 mL/m² [0.41, 2.2], respectively) and also with eccentric LV hypertrophy (OR 1.41 [1.10, 1.82], OR 1.53 [1.23, 1.91], respectively) and LV concentric remodeling (OR 1.38 [1.02, 1.87], OR 1.40 [1.06, 1.83], respectively) in adulthood (P < .05 for all). These relationships were only partly mediated by adult BMI.

CONCLUSIONS

Early growth patterns in infancy and childhood contribute to cardiac structure at midlife.

Basic Mechanisms of Diabetic Heart Disease

Diabetes mellitus predisposes affected individuals to a significant spectrum of cardiovascular complications, one of the most debilitating in terms of prognosis is heart failure. Indeed, the increasing global prevalence of diabetes mellitus and an aging population has given rise to an epidemic of diabetes mellitus-induced heart failure. Despite the significant research attention this phenomenon, termed diabetic cardiomyopathy, has received over several decades, understanding of the full spectrum of potential contributing mechanisms, and their relative contribution to this heart failure phenotype in the specific context of diabetes mellitus, has not yet been fully resolved. Key recent preclinical discoveries that comprise the current state-of-the-art understanding of the basic mechanisms of the complex phenotype, that is, the diabetic heart, form the basis of this review. Abnormalities in each of cardiac metabolism, physiological and pathophysiological signaling, and the mitochondrial compartment, in addition to oxidative stress, inflammation, myocardial cell death pathways, and neurohumoral mechanisms, are addressed. Further, the interactions between each of these contributing mechanisms and how they align to the functional, morphological, and structural impairments that characterize the diabetic heart are considered in light of the clinical context: from the disease burden, its current management in the clinic, and where the knowledge gaps remain. The need for continued interrogation of these mechanisms (both known and those yet to be identified) is essential to not only decipher the how and why of diabetes mellitus-induced heart failure but also to facilitate improved inroads into the clinical management of this pervasive clinical challenge.

Plasma antioxidants and oxidative stress status in obese women: correlation with cardiopulmonary response

INTRODUCTION

A high body fat coupled with low cardiopulmonary fitness and an increase in oxidative stress has been connoted as contributing factors in developing cardiovascular comorbidities. This study aimed to investigate the correlation between antioxidants and oxidative stress status with cardiopulmonary responses in women of different body mass index (BMI).

SUBJECTS AND METHODS

Eighty female adults were recruited and divided into three groups; normal weight (n = 23), overweight (n = 28) and obese (n = 29), according to their BMI. Blood samples were obtained prior to cardiopulmonary exercise testing. Plasma samples were separated by centrifugation and analysed for enzymatic antioxidant activity including catalase, glutathione peroxidase and superoxide dismutase. Non-enzymatic antioxidant activities were assessed using 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging and ferric reducing ability of plasma (FRAP) assays. To evaluate the oxidative stress status of subjects, levels of reactive oxygen species and malondialdehyde, the by-product of lipid peroxidation, were measured. Cardiopulmonary responses were analysed using cardiopulmonary exercise testing (CPET) which involved 15 various parameters such as peak oxygen consumption, metabolic equivalents and respiratory exchange ratio.

RESULTS

The obese group had significantly lower ABTS radical scavenging and FRAP activities than the normal weight group. A higher catalase activity was observed in the obese group than the normal weight group. Spearman's correlation showed an inverse relationship between catalase and peak oxygen consumption, while partial correlation analysis showed inverse correlations between superoxide dismutase and respiratory frequency, ABTS activity and oxygen pulse, and between ABTS activity and cardiac output.

CONCLUSION

Our results demonstrate a lower cardiovascular fitness and antioxidant capacity in obese women; the higher catalase activity may be a compensatory mechanism. The negative correlations found between these two parameters may indicate the potential effect of antioxidants on the cardiopulmonary system and deserve further analysis in a larger population. Nevertheless, this study provides the basis for future studies to further explore the relationships between redox status and cardiopulmonary responses. This can potentially be used to predict future risk of developing diseases associated with oxidative stress, especially pulmonary and cardiovascular diseases.

Obesity and heart failure with preserved ejection fraction: a paradox or something else?

Obesity represents one of the most common comorbidities in patients with heart failure and preserved ejection fraction (HFpEF). Studies have shown that obesity is not only a comorbidity, but it could also be an important risk factor for HFpEF development. The mechanisms that connect obesity and HFpEF vary from obesity-induced hemodynamic changes to important biohumoral systems such as adipocitokines, renin-angiotensin-aldosterone and sympathetic nervous systems, natriuretic peptide, and oxidative stress. Studies agree about the negative influence of morbid obesity on cardiac remodeling and HFpEF development. However, there is still no agreement regarding the relationship between body mass index, as the most commonly used parameter of obesity, and HFpEF incidence or outcome in patients who already have HFpEF. The relationship varies from the linear to the U-shaped and, therefore, the "obesity paradox," which refers to the reduced risk in mildly overweight subjects in comparison with normal and underweight individuals, deserves more attention not only in the research but also in the clinical approach to these patients. In the absence of a satisfactory pharmacological approach, which would improve the outcome of this large group of patients, alternative methods such as weight loss and physical activity seem to provide encouraging results. This review article provides a clinical overview of the available data about the mechanisms that connect obesity and HFpEF, the most relevant studies on this topic, clinical relevance of the obesity paradox, and the therapeutic approach including weight loss and physical activity in obese patients with HFpEF.

Caloric restriction reverses left ventricular hypertrophy through the regulation of cardiac iron homeostasis in impaired leptin signaling mice

Leptin-deficient and leptin-resistant mice manifest obesity, insulin resistance, and left ventricular hypertrophy (LVH); however, LVH’s mechanisms are not fully understood. Cardiac iron dysregulation has been recently implicated in cardiomyopathy. Here we investigated the protective effects of caloric restriction on cardiac remodeling in impaired leptin signaling obese mice. RNA-seq analysis was performed to assess the differential gene expressions in the heart of wild-type and ob/ob mice. In particular, to investigate the roles of caloric restriction on iron homeostasis-related gene expressions, 10-week-old ob/ob and db/db mice were assigned to ad libitum or calorie-restricted diets for 12 weeks. Male ob/ob mice exhibited LVH, cardiac inflammation, and oxidative stress. Using RNA-seq analysis, we identified that an iron uptake-associated gene, transferrin receptor, was upregulated in obese ob/ob mice with LVH. Caloric restriction attenuated myocyte hypertrophy, cardiac inflammation, fibrosis, and oxidative stress in ob/ob and db/db mice. Furthermore, we found that caloric restriction reversed iron homeostasis-related lipocalin 2, divalent metal transporter 1, transferrin receptor, ferritin, ferroportin, and hepcidin expressions in the heart of ob/ob and db/db mice. These findings demonstrate that the cardioprotective effects of caloric restriction result from the cellular regulation of iron homeostasis, thereby decreasing oxidative stress, inflammation, and cardiac remodeling. We suggest that decreasing iron-mediated oxidative stress and inflammation offers new therapeutic approaches for obesity-induced cardiomyopathy.

Ticagrelor reverses the mitochondrial dysfunction through preventing accumulated autophagosomes-dependent apoptosis and ER stress in insulin-resistant H9c2 myocytes

Ticagrelor, a P₂Y₁₂-receptor inhibitor, and a non-thienopyridine agent are used to treat diabetic patients via its effects on off-target mechanisms. However, the exact sub-cellular mechanisms by which ticagrelor exerts those effects remains to be elucidated. Accordingly, the present study aimed to examine whether ticagrelor influences directly the cardiomyocytes function under insulin resistance through affecting mitochondria-sarco(endo)plasmic reticulum (SER) cross-talk. Therefore, we analyzed the function and ultrastructure of mitochondria and SER in insulin resistance-mimicked (50-μM palmitic acid for 24-h) H9c2 cardiomyocytes in the presence or absence of ticagrelor (1-µM for 24-h). We found that ticagrelor treatment significantly prevented depolarization of mitochondrial membrane potential and increases in reactive oxygen species with a marked increase in the ATP level in insulin-resistant H9c2 cells. Ticagrelor treatment also reversed the increases in the resting level of free Ca²⁺ and mRNA level of P₂Y₁₂ receptors as well as preserved ER stress and apoptosis in insulin-resistant H9c2 cells. Furthermore, we determined marked repression with ticagrelor treatment in the increased number of autophagosomes and degeneration of mitochondrion, including swelling and loss of crista besides recoveries in enlargement and irregularity seen in SER in insulin-resistant H9c2 cells. Moreover, ticagrelor treatment could prevent the altered mRNA levels of Becklin-1 and type 1 equilibrative nucleoside transporter (ENT1), which are parallel to the preservation of ultrastructural ones. Our overall data demonstrated that ticagrelor can directly affect cardiomyocytes and provide marked protection against ER stress and dramatic induction of autophagosomes, and therefore, can alleviate the ER stress-induced oxidative stress increase and cell apoptosis during insulin resistance.