Structural and Metabolic Effects of Obesity on the Myocardium and the Aorta

The evaluation of bariatric surgery effect on cardiac structure and function using transthoracic echocardiography: a cohort study

BACKGROUND

Obesity is a pathology and a leading cause of death worldwide. Obesity can harm multiple organs, including the heart. In this study, we aim to investigate the effect of bariatric surgery and following weight loss on cardiac structure and functions using echocardiography parameters in patients with morbid obesity.

METHODS

In this cohort study, 30 patients older than 18 with BMI > 40 or BMI > 35 and comorbidity between March 2020 to March 2021 were studied. The patients underwent transthoracic echocardiography before and after six months of the bariatric surgery.

RESULTS

In total, 30 patients (28 women, 93.3%) with a mean age of 38.70 ± 9.19 were studied. Nine (30%) were diabetic, and 9 (30%) had hypertension. After six months of bariatric surgery, all physical measurements, including weight, Body mass index, and Body surface area, decreased significantly (p < 0.001). After bariatric surgery, all parameters regarding left ventricular morphology, including left ventricular mass, interventricular septal thickness, left ventricular posterior wall thickness, left ventricular end-systolic diameter, and left ventricular end-diastolic diameter, improved significantly (p < 0.001). Also, LVEF rose post-bariatric surgery (p < 0.001). TAPSE parameter indicating right ventricular function also improved (p < 0.001). Right ventricular diameter, left atrium volume, and mitral inflow E/e' decreased significantly (p < 0.001).

CONCLUSION

Systolic and diastolic parameters refine significantly after bariatric surgery in patients with obesity. Bariatric surgery lead to significant cardiac structure and function improvement.

Body Composition and Risk of Incident Heart Failure in 1 Million Adults: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Background The aim of this systematic review was to quantify the associations between body composition measures and risk of incident heart failure (HF) and its subtypes in the general population. Methods and Results We searched Medline, Embase, and Global Health databases from each database inception to January 19, 2023 for prospective studies reporting on body composition and HF risk. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Newcastle-Ottawa scale was used to assess the risk of bias of included studies. Fixed-effects models were used for meta-analysis. Thirty-five studies were included (ntotal=1 137 044; ncases=34 422). Summary relative risk (RR) per 5-kg/m2 higher body mass index was 1.42 (95% CI, 1.40-1.42; 𝜁2=0.02, I2=94.4%), 1.28 (95% CI, 1.26-1.31; 𝜁2=0.01, I2=75.8%) per 10-cm higher waist circumference, and 1.33 (95% CI, 1.28-1.37; 𝜁2=0.04, I2=94.9%) per 0.1-unit higher waist-hip ratio. Pooled estimates of the few studies that reported on regional fat suggested significant positive association between HF risk and both visceral fat (RR, 1.08 [95% CI, 1.04-1.12]) and pericardial fat (RR, 1.08 [95% CI, 1.06-1.10]). Among HF subtypes, associations were stronger for HF with preserved ejection fraction than HF with reduced ejection fraction. No study reported on lean mass. Conclusions Pooled data suggested strong associations between adiposity and HF. The association with adiposity is stronger for HF with preserved ejection fraction than HF with reduced ejection fraction, indicating that different mechanisms may be at play in etiopathogenesis of HF subtypes. Future studies are needed to investigate role of regional fat mass and lean mass in HF risk. Registration Information REGISTRATION: URL: www.crd.york.ac.uk/prospero/. Unique identifier: CRD42020224584.

Morphological changes in the heart and aorta of rats with diet-induced metabolic syndrome

Aim. To identify early morphological changes in the heart and aorta of rats with experimental metabolic syndrome induced by a high-fat and high-carbohydrate diet (HFHCD).

Materials and methods. The study was carried out on male Wistar rats. The animals were divided into two groups: a control group (n = 10) and an experimental group (n = 10). The rats from the control group were fed with a standard laboratory diet. The rats from the experimental group received HFHCD for 12 weeks. Body weight, blood pressure (BP), and individual parameters of carbohydrate and lipid metabolism were assessed in the rats.   A histologic examination of the heart and aorta in the animals was performed.

Results. Feeding rats with HFHCD led to an increase in body weight, elevation of BP, obesity, hyperglycemia, and triglyceridemia. The histologic examination of the heart in the rats of the experimental group showed signs of vascular disease, lipomatosis, and focal myocardial degeneration. Lipid accumulation in the cells of the media, hyperplasia of adipocytes in the adventitia, and depletion and fragmentation of the elastic lamina were revealed in the aortic wall of the rats receiving HFHCD.

Conclusion. The study indicated that HFHCD is an effective way to model metabolic syndrome. Structural disorders in the heart and aorta may be the mainstay for the development of cardiomyopathy and arterial hypertension in diet-induced metabolic syndrome.

Relationship between overweight and obesity and cardiac dimensions and function in a paediatric population

Obesity in adults is associated with left ventricular hypertrophy, dilatation, and myocardial fibrosis, as well as heart failure and coronary heart disease. These associations have been studied to a lesser extent in the paediatric population. This study aims to investigate the relationship between obesity and cardiac structure and function in the paediatric population. In a southern Spanish village, we selected all inhabitants aged 6-17 years stratifying by age, gender, and educational centres. We performed a complete transthoracic echocardiogram evaluating all the cardiac morphological and functional parameters commonly measured in an echocardiographic study. There were 212 children and adolescents included. Of them, 48.1% were males. The mean age was 10.9 ± 3.0 years. A total of 106 (50%) were normal weight, 57 (26.9%) overweight, and 49 (23.1%) obese. Sex and age were similar in all three groups. Overweight and obesity were associated with larger left ventricular end-diastolic and end-systolic volumes (p < 0.0005), greater left ventricular mass (p < 0.0005), and smaller ejection fraction (p < 0.0005). They were also associated with larger atrial, aortic, and right ventricular size. Lateral and mean E/e' ratios were higher (p = 0.007 and p = 0.01 respectively). Body mass index was independently associated with all cavity size variables as well as left ventricular ejection fraction.

CONCLUSION

Childhood obesity is independently associated with larger heart chambers, greater left ventricle mass, and smaller left ventricle ejection fraction.

WHAT IS KNOWN

• Childhood obesity is related to the development of cardiovascular risk factors and is considered an epidemic of the twenty-first century; its prevalence is rising.

WHAT IS NEW

• Childhood overweight and obesity lead to changes in cardiac structure and function which, although not considered clinically pathological, are significant and a result of obesity, and which behave as unfavourable incipient alterations at an early age.

Fat cardiomyopathy in patients with severe degree of obesity. Case report

Currently, the world is constantly increasing the number of people with obesity. As was shown by the Framingham study, obesity is a risk factor for many cardiovascular diseases. The effect of obesity on the structure and function of the heart is manifested in the form of cardiac remodeling, the effect on energy metabolism in the heart and infiltration of both myocardium with lipids, and an increase in the accumulation of adipose tissue in the pericardium, imbalance of adipokines and activation of inflammatory markers. Cardiac remodeling occurs primarily due to thickening of the left ventricle (LV) walls and an increase in the LV myocardium mass. Systolic dysfunction of the heart is less common in obese individuals compared with diastolic dysfunction. However, more modern methods (tissue Doppler, visualization of the deformation of the chambers of the heart strain imaging) reveal a subclinical decrease in systolic function in people with obesity. It is not fully known whether obesity is associated with systolic dysfunction, regardless of other risk factors. In any case, it has been proven that heart failure in people with obesity can develop independently of other risk factors. As an illustration, we give an example when the presence of obesity and concomitant pathology (arterial hypertension, diabetes) led to the development of systolic dysfunction with a decrease in the LV ejection fraction to 35% (fat cardiopathy), which show the potential for the influence of both obesity itself and in combination with concomitant diseases to lead to severe systolic heart failure.

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.

The Anti-Inflammatory Effect of Taurine on Cardiovascular Disease

Taurine is a non-protein amino acid that is expressed in the majority of animal tissues. With its unique sulfonic acid makeup, taurine influences cellular functions, including osmoregulation, antioxidation, ion movement modulation, and conjugation of bile acids. Taurine exerts anti-inflammatory effects that improve diabetes and has shown benefits to the cardiovascular system, possibly by inhibition of the renin angiotensin system. The beneficial effects of taurine are reviewed.

Obesity-related ventricular remodelling is exacerbated in dilated and hypertrophic cardiomyopathy

Background

Obesity causes significant cardiac remodelling even in health, and yet the contribution of this maladaptation in the setting of an additional cardiomyopathic process is poorly understood. Cardiovascular magnetic resonance is the gold-standard tool for assessing cardiac geometry, especially in an obese population, and hence perfectly suited to investigate this important question.

Methods

Using data from our extensive imaging registry (n=1,554), we documented the relationship between increasing BMI and left ventricular (LV) remodelling in patients with dilated (DCM; n=529) and hypertrophic cardiomyopathy (HCM; n=297), compared to the normal heart (n=728).

Results

Regardless of cardiac status, increasing BMI resulted in similar increases in LV stroke volume (P>0.18). However, there was a difference in the degree of LV cavity dilatation associated with this change in stroke volume; when compared to normal hearts [increase in end-diastolic volume of 0.7 mL per unit of rising BMI (mL/kg/m²)], there was a threefold greater LV cavity dilatation in DCM (+2.2 mL/kg/m²) and twofold greater in HCM (+1.9 mL/kg/m², all P<0.04). Whilst obesity was related to LV hypertrophy in all groups (normal +1.3 g, DCM +2.2g, HCM +2.3 g/kg/m², all P<0.001), additional obesity-related concentric LV remodelling only occurred in normal hearts and DCM (normal +0.006 vs. +0.003 mass:volume ratio, both P<0.001).

Conclusions

In both DCM and HCM, the increase in stroke volume required by obesity appears to be achieved by excessive LV cavity dilatation. The impact of obesity on LV geometry was more pronounced in concomitant cardiovascular disease, and therefore carries potential to become an important therapeutic target in cardiomyopathy.

The use of cardiovascular magnetic resonance for the assessment of left ventricular hypertrophy

Cardiovascular magnetic resonance (CMR) is a powerful tool to assess and diagnose the cause of left ventricular hypertrophy (LVH). This review provides an overview of the typical CMR findings in the various causes of LVH, focusing mainly on late gadolinium enhancement (LGE) imaging. It will also cover the more novel techniques of T1 mapping, extracellular volume (ECV) fraction estimation and diffusion tensor imaging (DTI) and their role in the imaging assessment of LVH.

Obesity and Mechanisms of its Negative Impact on the Cardiovascular System

Currently, the number of obese people in the world is constantly increasing. Obesity has a direct negative impact on the heart and blood vessels, which can be considered not only as an appropriate response to an increase in the volume of circulating blood due to an increase in body weight, but also as a side tissue reaction of the myocardium to hormonal and metabolic changes inherent in obesity. Our review is devoted to the description of the mechanisms of influence of obesity on the structural and functional parameters of the heart, which create prerequisites for the development of cardiovascular diseases, as well as the existing contradictions. Currently, the accumulated data suggest that an excessive amount of adipose tissue, in addition to metabolic disorders, including insulin resistance, imbalance of adipokines and inflammation markers, leading to the development of lipotoxicity, can directly penetrate the myocardium and cause violations of its contractile properties, as well as affect the conduction of excitation pulses and provoke the development of rhythm and conduction disorders. The development of endothelial dysfunction in obesity ultimately leads to the development of atherosclerosis and coronary heart disease. In addition, obesity contributes to the emergence of risk factors for hypertension, diabetes, atrial fibrillation, chronic heart failure, obstructive sleep apnea syndrome. Given the differences in the literature on the effect of obesity on long-term outcomes in patients with cardiovascular diseases, it is important to conduct prospective studies on the role of individual factors and their combinations that affect the mortality of patients with cardiovascular diseases.

Obesity and its cardiovascular effects

Obesity is described in terms of body fat percentage or body mass index (BMI), despite the fact that these measures do not give full insight about the body fat distribution. It is presently a consistently growing universal challenge since it has tripled in the last 10 years, killing approximately 28 million people each year. In this review, we aim to clarify the different results of obesity on the working and physiology of the cardiovascular system and to reveal changes in the obesity "paradox"-a variety of cardiovascular outcomes in typical/overweight people. Central fat build-up in ordinary/overweight populaces has been related to expanded occurrences of myocardial infarction, heart failure, or all-cause mortality when contrasted with the obese populace. These discoveries are additionally clarified as the abundance and prolonged vulnerability to free fatty acids (FFAs) in obesity. This has been believed to cause the myocardial substrate to move from glucose to FFAs digestion, which causes lipid gathering in cardiomyocytes, spilling over to other lean tissues, and prompting a general atherogenic impact. This cardiomyocyte lipid aggregation has been demonstrated to cause insulin resistance and cardiovascular hypertrophy, and to lessen the heart functions in general. There is a proof backing the fact that fat tissue is not only an energy reservoir, it also coordinates hormones and proinflammatory cytokines and deals with the energy transition of the body by putting away abundant lipids in diverse tissues.

Adenosine stress CMR T1-mapping detects early microvascular dysfunction in patients with type 2 diabetes mellitus without obstructive coronary artery disease

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with coronary microvascular dysfunction in the absence of obstructive coronary artery disease (CAD). Cardiovascular magnetic resonance (CMR) T1-mapping at rest and during adenosine stress can assess coronary vascular reactivity. We hypothesised that the non-contrast T1 response to vasodilator stress will be altered in patients with T2DM without CAD compared to controls due to coronary microvascular dysfunction.

METHODS

Thirty-one patients with T2DM and sixteen matched healthy controls underwent CMR (3 T) for cine, rest and adenosine stress non-contrast T1-mapping (ShMOLLI), first-pass perfusion and late gadolinium enhancement (LGE) imaging. Significant CAD (>50% coronary luminal stenosis) was excluded in all patients by coronary computed tomographic angiography.

RESULTS

All subjects had normal left ventricular (LV) ejection and LV mass index, with no LGE. Myocardial perfusion reserve index (MPRI) was lower in T2DM than in controls (1.60 ± 0.44 vs 2.01 ± 0.42; p = 0.008). There was no difference in rest native T1 values (p = 0.59). During adenosine stress, T1 values increased significantly in both T2DM patients (from 1196 ± 32 ms to 1244 ± 44 ms, p < 0.001) and controls (from 1194 ± 26 ms to 1273 ± 44 ms, p < 0.001). T2DM patients showed blunted relative stress non-contrast T1 response (T2DM: ΔT1 = 4.1 ± 2.9% vs.

CONTROLS

ΔT1 = 6.6 ± 2.6%, p = 0.007) due to a blunted maximal T1 during adenosine stress (T2DM 1244 ± 44 ms vs. controls 1273 ± 44 ms, p = 0.045).

CONCLUSIONS

Patients with well controlled T2DM, even in the absence of arterial hypertension and significant CAD, exhibit blunted maximal non-contrast T1 response during adenosine vasodilatory stress, likely reflecting coronary microvascular dysfunction. Adenosine stress and rest T1 mapping can detect subclinical abnormalities of the coronary microvasculature, without the need for gadolinium contrast agents. CMR may identify early features of the diabetic heart phenotype and subclinical cardiac risk markers in patients with T2DM, providing an opportunity for early therapeutic intervention.

Mild and Short-Term Caloric Restriction Prevents Obesity-Induced Cardiomyopathy in Young Zucker Rats without Changing in Metabolites and Fatty Acids Cardiac Profile

Caloric restriction (CR) ameliorates cardiac dysfunction associated with obesity. However, most of the studies have been performed under severe CR (30-65% caloric intake decrease) for several months or even years in aged animals. Here, we investigated whether mild (20% food intake reduction) and short-term (2-weeks) CR prevented the obese cardiomyopathy phenotype and improved the metabolic profile of young (14 weeks of age) genetically obese Zucker fa/fa rats. Heart weight (HW) and HW/tibia length ratio was significantly lower in fa/fa rats after 2 weeks of CR than in counterparts fed ad libitum. Invasive pressure measurements showed that systolic blood pressure, maximal rate of positive left ventricle (LV) pressure, LV systolic pressure and LV end-diastolic pressure were all significantly higher in obese fa/fa rats than in lean counterparts, which were prevented by CR. Magnetic resonance imaging revealed that the increase in LV end-systolic volume, stroke volume and LV wall thickness observed in fa/fa rats was significantly lower in animals on CR diet. Histological analysis also revealed that CR blocked the significant increase in cardiomyocyte diameter in obese fa/fa rats. High resolution magic angle spinning magnetic resonance spectroscopy analysis of the LV revealed a global decrease in metabolites such as taurine, creatine and phosphocreatine, glutamate, glutamine and glutathione, in obese fa/fa rats, whereas lactate concentration was increased. By contrast, fatty acid concentrations in LV tissue were significantly elevated in obese fa/fa rats. CR failed to restore the LV metabolomic profile of obese fa/fa rats. In conclusion, mild and short-term CR prevented an obesity-induced cardiomyopathy phenotype in young obese fa/fa rats independently of the cardiac metabolic profile.

Improvements in ECG accuracy for diagnosis of left ventricular hypertrophy in obesity

OBJECTIVES

The electrocardiogram (ECG) is the most commonly used tool to screen for left ventricular hypertrophy (LVH), and yet current diagnostic criteria are insensitive in modern increasingly overweight society. We propose a simple adjustment to improve diagnostic accuracy in different body weights and improve the sensitivity of this universally available technique.

METHODS

Overall, 1295 participants were included-821 with a wide range of body mass index (BMI 17.1-53.3 kg/m(2)) initially underwent cardiac magnetic resonance evaluation of anatomical left ventricular (LV) axis, LV mass and 12-lead surface ECG in order to generate an adjustment factor applied to the Sokolow-Lyon criteria. This factor was then validated in a second cohort (n=520, BMI 15.9-63.2 kg/m(2)).

RESULTS

When matched for LV mass, the combination of leftward anatomical axis deviation and increased BMI resulted in a reduction of the Sokolow-Lyon index, by 4 mm in overweight and 8 mm in obesity. After adjusting for this in the initial cohort, the sensitivity of the Sokolow-Lyon index increased (overweight: 12.8% to 30.8%, obese: 3.1% to 27.2%) approaching that seen in normal weight (37.8%). Similar results were achieved in the validation cohort (specificity increased in overweight: 8.3% to 39.1%, obese: 9.4% to 25.0%) again approaching normal weight (39.0%). Importantly, specificity remained excellent (>93.1%).

CONCLUSIONS

Adjusting the Sokolow-Lyon index for BMI (overweight +4 mm, obesity +8 mm) improves the diagnostic accuracy for detecting LVH. As the ECG, worldwide, remains the most widely used screening tool for LVH, implementing these findings should translate into significant clinical benefit.

Effects of exercise and L-arginine intake on inflammation in aorta of high-fat diet induced obese rats

PURPOSE

In the present study, we investigated the effect of exercise and arginine on the inflammatory makers and Cu-Mn superoxide dismutase (SOD) expression in the aortas of high-fat-induced obese rats.

METHODS

Fifty 6-month-old male Sprague-Dawley rats were randomly assigned as follows: HF-Con: high-fat diet, HF-Ex: high-fat diet and exercise, HF-Ex+A: high-fat diet and combined exercise and arginine, HF-A: high-fat diet and arginine. The high-fat diet was fed for 12 weeks following 1 week of environmental adaptation with mixed solid chow. The rats performed treadmill exercise 6 times per week for 12 weeks at20 m/min for 60 min. L-argininewas mixed with saline and orally administered at 150 mg/kg once a day. Expressions of inflammatory markers (including NF- κB, TNF-α, COX-2) and SOD were evaluated using western blotting.

RESULTS

NF-κB expression decreased significantly (p<0.05) in the HF-Ex group compared with HF-Con group, and we found additional effects(p<0.01) on NF-κB expression in HF-EX+A compared withHF-Ex. TNF-α expression decreased significantly (p<0.01) in HF-Ex, FH-Ex+A, and FH-A compared with HF-Con. In a similar trend with NF-κB expression, COX-2 expression decreased significantly in HF-Ex compared withHF-Con. In Cu-Mn SOD expression, there was no difference between HF and HF-Ex, but significant increases (p<0.01) inCu-Mn SOD werefound in HF-Ex+A and HF-A.

CONCLUSION

Based on our results, treatment that combines exercise and arginine might be effective for modulatingvascular inflammation and oxidative stress in obesity.