Decreases in neprilysin and vasoconstrictors and increases in vasodilators following bariatric surgery

Neprilysin activity is increased in metabolic dysfunction-associated steatotic liver disease and normalizes after bariatric surgery or GLP-1 therapy

Inhibitors of neprilysin improve glycemia in patients with heart failure and type 2 diabetes (T2D). The effect of weight loss by diet, surgery, or pharmacotherapy on neprilysin activity (NEPa) is unknown. We investigated circulating NEPa and neprilysin protein concentrations in obesity, T2D, metabolic dysfunction-associated steatotic liver disease (MASLD), and following bariatric surgery, or GLP-1-receptor-agonist therapy. NEPa, but not neprilysin protein, was enhanced in obesity, T2D, and MASLD. Notably, MASLD associated with NEPa independently of BMI and HbA1c. NEPa decreased after bariatric surgery with a concurrent increase in OGTT-stimulated GLP-1. Diet-induced weight loss did not affect NEPa, but individuals randomized to 52-week weight maintenance with liraglutide (1.2 mg/day) decreased NEPa, consistent with another study following 6-week liraglutide (3 mg/day). A 90-min GLP-1 infusion did not alter NEPa. Thus, MASLD may drive exaggerated NEPa, and lowered NEPa following bariatric surgery or liraglutide therapy may contribute to the reported improved cardiometabolic effects.

Vasoactive mediators of hypertension in obesity

Obesity is associated with hypertension. However, the mechanisms involved are not fully understood. Therefore, we investigated the relationship between obesity and vasoactive mediators. In this cross-sectional study, blood pressure (BP) and vasoactive mediators of hypertension are compared among 135 adults in the nonobese, obese, and morbidly obese body mass index (BMI) ranges (BMI ≤27, 30-40, and >40 kg/m2, respectively). Angiotensinogen, angiotensin II, renin, aldosterone, endothelin-1 (ET-1), neprilysin, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), cyclic guanosine monophosphate (cGMP), and cyclic adenosine monophosphate (cAMP) levels were measured and their relationship to BP, BMI, race, and gender were investigated. Systolic and diastolic BP (SBP and DSP) were significantly higher in subjects with obesity and morbid obesity compared with nonobese. Angiotensin II, ET-1, and neprilysin were significantly higher in subjects with morbid obesity while BNP was lower. Levels of angiotensinogen, renin, aldosterone, ANP, cGMP, and cAMP did not differ between the groups. BMI was positively related to SBP, DBP, angiotensin II, ET-1, and neprilysin, and inversely related to cGMP and BNP. Age, male gender, and African-American race were associated with higher SBP. SBP was positively related to angiotensin II and ET-1 and inversely related to aldosterone, renin, and cGMP. On multivariate analyses, age, BMI, gender, and race were the main determinants of SBP, and excluding these variables, angiotensin II, aldosterone, renin, and ET-1 accounted for 21.1% ability to predict SBP. Obesity, especially morbid obesity, is associated with higher BP, higher angiotensin II and ET-1 (vasoconstrictors), and lower levels BNP and cGMP (vasodilators). SBP variability can be partly explained by angiotensin II, aldosterone, renin, and ET-1.NEW & NOTEWORTHY Our data show that obesity, especially morbid obesity, is associated with higher blood pressure levels and increases angiotensin II and endotherlin-1 (ET-1) (vasoconstrictors) and lower levels BNP and cGMP (vasodilators) and that systolic blood pressure variability can be partly explained by levels of angiotensin II, aldosterone, renin, and ET-1. The effect of these mediators on blood pressure is in addition to the effects of other known factors related to age, male gender, and AA race.

Cardiovascular Effects of Weight Loss in Obese Patients with Diabetes: Is Bariatric Surgery the Additional Arrow in the Quiver?

Obesity is an increasingly widespread disease worldwide because of lifestyle changes. It is associated with an increased risk of cardiovascular disease, primarily type 2 diabetes mellitus, with an increase in major cardiovascular adverse events. Bariatric surgery has been shown to be able to reduce the incidence of obesity-related cardiovascular disease and thus overall mortality. This result has been shown to be the result of hormonal and metabolic effects induced by post-surgical anatomical changes, with important effects on multiple hormonal and molecular axes that make this treatment more effective than conservative therapy in determining a marked improvement in the patient's cardiovascular risk profile. This review, therefore, aimed to examine the surgical techniques currently available and how these might be responsible not only for weight loss but also for metabolic improvement and cardiovascular benefits in patients undergoing such procedures.

Regulatory role of atrial natriuretic peptide in brown adipose tissue: A narrative review

Atrial natriuretic peptide (ANP) has been considered to exert an essential role as a cardiac secretory hormone in the regulation of hemodynamic homeostasis. As the research progresses, the role of ANP in the crosstalk between heart and lipid metabolism has become an interesting topic that is attracting the interest of researchers. The regulation of ANP in lipid metabolism shows favorable effects, particularly the activation of brown adipose tissue (BAT). The complex regulatory network of ANP on BAT has not been fully outlined. This narrative review critically evaluated the existing literature on the regulatory effects of ANP on BAT. In general, we have summarized the expression of ANP and its receptors in various human tissues, analyzed the progress of research on the relationship between the ANP and BAT, and described several potential pathways of ANP to BAT. Exogenous ANP, natriuretic peptide receptor C (NPRC) deficiency, cold exposure, bariatric surgery, and cardiac or renal insufficiency could all contribute to BAT expression by increasing circulating ANP levels.

The Impact of Bariatric Surgery Versus Non-Surgical Treatment on Blood Pressure: Systematic Review and Meta-Analysis

The purpose of this study was to compare bariatric surgery versus non-surgical treatment on blood pressure for patients with obesity. Nineteen RCTs (1353 total patients) were included. In the pooled analyses, bariatric surgery reduces more systolic blood pressure (WMD: - 3.937 mmHg, CI95%: - 6.000 to - 1.875, p < 0.001, I² = 0%), diastolic blood pressure (WMD: - 2.690 mmHg, CI95%: - 3.994 to - 1.385, P < 0.001, I² = 0%) and more antihypertensives. In subgroup analyses, patients after Roux-en-Y gastric bypass, with poor control of hypertension (BP > 130/80 mmHg) and diabetes mellitus (HbA1C > 7.0%, FPG > 7.0 mmol/L), elder patients (> 45 years), non-severe obesity (BMI < 40 kg/cm², body weight < 120 kg), less waist circumference (< 115 cm) tend to decrease more blood pressure. Besides, patients after surgery also lost more weight (p < 0.001), decreased more waist circumference (p < 0.001), fasting plasma glucose (p < 0.001), glycosylated hemoglobin (p < 0.001), triglycerides (p < 0.001), hsCRP (p = 0.001), increased more high-density lipoprotein cholesterol (p < 0.001), and had better remission of metabolic syndrome (p < 0.001). Changes in total cholesterol, low-density lipoprotein cholesterol, renal function, resting heart rate, and 6-min walking test were not significantly different. Therefore, bariatric surgery is more effective than non-surgical treatment in controlling patients' blood pressure.

Heart failure with preserved ejection fraction based on aging and comorbidities

Heart failure (HF) with preserved ejection fraction (HFpEF) is a leading cause of hospitalizations and mortality when diagnosed at the age of ≥ 65 years. HFpEF represents multifactorial and multisystemic syndrome and has different pathophysiology and phenotypes. Its diagnosis is difficult to be established based on left ventricular ejection fraction and may benefit from individually tailored approaches, underlying age-related changes and frequent comorbidities. Compared with the rapid development in the treatment of heart failure with reduced ejection fraction, HFpEF presents a great challenge and needs to be addressed considering the failure of HF drugs to improve its outcomes. Further extensive studies on the relationships between HFpEF, aging, and comorbidities in carefully phenotyped HFpEF subgroups may help understand the biology, diagnosis, and treatment of HFpEF. The current review summarized the diagnostic and therapeutic development of HFpEF based on the complex relationships between aging, comorbidities, and HFpEF.

Dapagliflozin reduces systolic blood pressure and modulates vasoactive factors

AIM

To investigate the mechanisms underlying improvements in blood pressure (BP) and congestive heart failure outcomes following treatment with dapagliflozin, a sodium-glucose co-transporter-2 inhibitor.

RESEARCH DESIGN AND METHODS

A total of 52 patients with type 2 diabetes (T2D) with an HbA1c of less than 8% participated in this prospective, double-blind and placebo-controlled study. Patients were randomized (1:1) to either dapagliflozin 10 mg daily or placebo for 12 weeks. Half the patients were also monitored for 6 h following their first dose for acute effects on BP. Blood and urine samples were collected and levels of angiotensinogen, angiotensin II, renin, aldosterone, endothelin-1, atrial natriuretic peptide (ANP), brain natriuretic peptide, cyclic adenosine monophosphate, cyclic guanosine monophosphate (cGMP) and neprilysin were measured. The expression of angiotensin-converting enzyme, guanylate cyclase and phosphodiesterase 5 (PDE5) was measured in circulating mononuclear cells (MNC).

RESULTS

A total of 24 and 23 patients receiving dapagliflozin and placebo, respectively, completed the 12-week study. Systolic BP decreased significantly, compared with placebo, both after single-dose (by 7 ± 3 mmHg) and 12-week (by 7 ± 2 mmHg) treatment with dapagliflozin. Dapagliflozin suppressed angiotensin II and angiotensinogen (by 10.5 ± 2.1 and 1.45 ± 0.42 μg/mL, respectively) and increased ANP and cGMP (by 34 ± 11 and 29 ± 11 pmol/mL, respectively) compared with the placebo group. cGMP levels also increased acutely following a single dose of dapagliflozin. Dapagliflozin also suppressed PDE5 expression by 26% ± 11% in MNC. There were no changes observed in the other vasoactive mediators investigated.

CONCLUSIONS

Dapagliflozin administration in T2D resulted in both acute and chronic reduction in systolic BP, a reduction in vasoconstrictors and an increase in vasodilators. These changes may potentially contribute to its antihypertensive effects and its benefits in congestive cardiac failure.

Effect of laparoscopic sleeve gastrectomy on vasoactive mediators in obese hypertensive patients: A prospective study

INTRODUCTION

The causal relationship between obesity and high blood pressure is established; however, the detailed pathways for such association are still under research. This work aims to assess the changes in neprilysin, vasoconstrictor and vasodilatory molecules in obese hypertensive patients undergoing laparoscopic sleeve gastrectomy (LSG).

PATIENTS

The present prospective study was done on 59 hypertensive obese patients in whom LGS was performed. Blood pressure, as well as blood samples for neprilysin, angiotensinogen, angiotensin II, renin, endothelin-1 "ET-1", aldosterone, atrial natriuretic peptide "ANP" and B-type natriuretic peptide "BNP", were assessed before and 15 months after surgery. Patients were divided into two groups according to the remission of hypertension (HTN).

RESULTS

After 15 months, remission of hypertension was seen in 42 patients (71%). The declines in the following measurements were significantly higher in patients with remission than those with persistent HTN: aldosterone (p = .029567), angiotensin II (p < .000001), angiotensinogen (p = .000021), neprilysin (p = .000601), renin (p = .000454) and endothelin-1(p = .000030). There was a significantly higher increment in ANP (p = .000002) and a non-significant increment in BNP (p = .081740). Angiotensin II 15 months after LSG and Δ ANP % were significant independent predictors of persistent HTN.

CONCLUSION

In the setting of LSG, aldosterone, angiotensinogen, angiotensin II, renin and neprilysin were significantly lower in patients with remission of HTN after 15 months than those with persistent HTN, and natriuretic peptides were significantly higher. A lower postoperative level of angiotensin II and a larger percentage increment of ANP are independently associated with hypertension remission after LSG.

Effect of bariatric surgery on natriuretic peptide levels: a systematic review and meta-analysis

The effect of bariatric surgery on natriuretic peptide levels in patients with obesity is unclear. The purpose of this study was to conduct a systematic review and meta-analysis to determine the effect of bariatric surgery on BNP and NT-proBNP levels. MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched to February 2020. Primary outcomes included change in NT-proBNP or BNP levels following bariatric surgery and change in weight and body mass index (BMI). Secondary outcomes included change in blood pressure, echocardiographic findings, and heart failure symptoms. MINORS tool was used to assess quality of evidence. Twelve studies with 622 patients were included. Most patients underwent Roux-en-Y gastric bypass (RYGB) (70.5%). Mean absolute reduction in BMI was 23%. NT-proBNP levels increased significantly from baseline at 6 months (mean difference (MD) 53.67 pg/mL; 95% CI, 28.72-78.61; P = <0.001, I2 = 99%; 8 studies) and 12 months (MD 51.16 pg/mL; 95% CI, 20.46-81.86; P = 0.001, I2 = 99%; 8 studies) post-bariatric surgery. BNP levels also increased significantly at 6 months (MD 17.57 pg/mL; 95% CI, 7.62-27.51; P <0.001, I2 = 95%; 4 studies). Systolic and diastolic blood pressure decreased significantly 12 months after surgery. Studies measuring echocardiographic findings saw improvement in LV mass and E/A ratio, but no significant change in ejection fraction. Bariatric surgery is associated with increased natriuretic peptide levels in the absence of deteriorating cardiac function, and may be associated with improved cardiac and metabolic function after the procedure.

Lifestyle interventions for the prevention and treatment of hypertension

Hypertension affects approximately one third of the world's adult population and is a major cause of premature death despite considerable advances in pharmacological treatments. Growing evidence supports the use of lifestyle interventions for the prevention and adjuvant treatment of hypertension. In this Review, we provide a summary of the epidemiological research supporting the preventive and antihypertensive effects of major lifestyle interventions (regular physical exercise, body weight management and healthy dietary patterns), as well as other less traditional recommendations such as stress management and the promotion of adequate sleep patterns coupled with circadian entrainment. We also discuss the physiological mechanisms underlying the beneficial effects of these lifestyle interventions on hypertension, which include not only the prevention of traditional risk factors (such as obesity and insulin resistance) and improvements in vascular health through an improved redox and inflammatory status, but also reduced sympathetic overactivation and non-traditional mechanisms such as increased secretion of myokines.

Narcolepsy, depression, and severe flushing in an obese man

Hypogonadism as a cause of depression, daytime sleepiness, and flushing is often missed in young males. Our case report highlights the importance of screening for hypogonadotropic hypogonadism and its treatment in symptomatic men with severe obesity, especially if they have depression, excessive sleepiness, and narcolepsy.

Bariatric Surgery: Remission of Inflammation, Cardiometabolic Benefits, and Common Adverse Effects

Obesity is associated with increased mortality as a result of several comorbidities which occur in tandem with the obese state. Chronic inflammation is well documented in obesity, and evidence from numerous studies support the notion that the increased inflammation in individuals with obesity accentuates the comorbidities seen in this condition. The remission of comorbidities such as metabolic, cardiovascular, and neurological complications occurs following bariatric procedures. Bariatric surgery significantly reduces mortality and results in remarkable weight loss and reversal in several obesity-related comorbidities. There is indisputable evidence that the resolution of inflammation that occurs after bariatric surgery mitigates some of these comorbidities. With the increasing use of bariatric surgery for the treatment of severe obesity, it is pivotal to elucidate the underlying mechanisms responsible for the notable improvements seen after the procedure. This review summarizes underlying mechanisms responsible for the remission of obesity-related abnormalities and discusses the common adverse effects of bariatric surgery. Well-stratified, large-scale studies are still needed for a proper evaluation of these underlying mechanisms.

Link Between Synovial and Myocardial Inflammation: Conceptual Framework to Explain the Pathogenesis of Heart Failure with Preserved Ejection Fraction in Patients with Systemic Rheumatic Diseases

Patients with a broad range of systemic rheumatic diseases are at increased risk of heart failure (HF), an event that is not related to traditional cardiovascular risk factors or underlying ischaemic heart disease. The magnitude of risk is linked to the severity of arthritic activity, and HF is typically accompanied by a preserved ejection fraction. Subclinical evidence for myocardial fibrosis, microcirculatory dysfunction and elevated cardiac filling pressures is present in a large proportion of patients with rheumatic diseases, particularly those with meaningful systemic inflammation. Drugs that act to attenuate pro-inflammatory pathways (methotrexate and antagonists of tumour necrosis factor and interleukin-1) may ameliorate myocardial inflammation and cardiac structural abnormalities and reduce the risk of HF events.

Cardiovascular Effects of Metabolic Surgery on Type 2 Diabetes

INTRODUCTION

Cardiovascular, together with renal disease, claims a significant proportion of morbidity and mortality in association with type 2 diabetes mellitus (T2DM) and obesity. To improve the long-term renal and cardiovascular outcome, there is the incorporation of bariatric surgery (BS), which seems to be a pivotal intervention. Areas Explored: Cohort studies and randomized controlled trial (RCT) research of BS among patients with T2DM, were conducted by screening, and then information on renal effects and the cardiovascular outcome was gathered. Metabolic surgery (MS) and BS reduce both mortality and the risk of cardiovascular disorder, chronic kidney diseases and albuminuria. MS refers to a surgical approach, the primary intent of which is the control of metabolic alterations/hyperglycemia in contrast to BS which is a mere weight-reduction therapy. Patients suffering from poor glycaemic control and other macro and micro-vascular diseases will benefit from a surgical approach. The approach implicates hypertension glomerular remission, gut microbiota shift, reduced renal inflammation and fewer instances of chronic cardiac remodelling.

CONCLUSION

MS is beneficial where the main aim is to attain significant and long-lasting weight loss results. The RCTs have depicted the superiority which surgical mechanisms hold over medically- based therapy, for enhancing glycaemic control, and achieving remission of diabetes. This type of surgery improves life quality, reduces incidences of other obesity and diabetes related diseases like microvascular disases, sleep apnea, fatal disorder, and fatty liver disease.

Do most patients with obesity or type 2 diabetes, and atrial fibrillation, also have undiagnosed heart failure? A critical conceptual framework for understanding mechanisms and improving diagnosis and treatment

Obesity and diabetes can lead to heart failure with preserved ejection fraction (HFpEF), potentially because they both cause expansion and inflammation of epicardial adipose tissue and thus lead to microvascular dysfunction and fibrosis of the underlying left ventricle. The same process also causes an atrial myopathy, which is clinically evident as atrial fibrillation (AF); thus, AF may be the first manifestation of HFpEF. Many patients with apparently isolated AF have latent HFpEF or subsequently develop HFpEF. Most patients with obesity or diabetes who have AF and exercise intolerance have increased left atrial pressures at rest or during exercise, even in the absence of diagnosed HFpEF. Among patients with AF, those who also have latent HFpEF have increased risk for systemic thromboembolism and death. The identification of HFpEF in patients with obesity or diabetes alters the risk-to-benefit relationship of commonly prescribed treatments. Bariatric surgery and statins can ameliorate AF and reduce the risk for HFpEF. Conversely, antihyperglycaemic drugs that promote adipogenesis or cause sodium retention (insulin and thiazolidinediones) may increase the risk for heart failure in patients with an underlying ventricular myopathy. Patients with obesity and diabetes who undergo catheter ablation for AF are at increased risk for AF recurrence and for post-ablation increases in pulmonary venous pressures and worsening heart failure, especially if HFpEF coexists. Therefore, AF may be the earliest indicator of HFpEF in patients with obesity or type 2 diabetes, and recognition of HFpEF alters the management of these patients.

Macronutrient-Mediated Inflammation and Oxidative Stress: Relevance to Insulin Resistance, Obesity, and Atherogenesis

CONTEXT

The intake of macronutrients as components of a Western dietary pattern leads to oxidative stress and inflammation.

EVIDENCE ACQUISITION

Data were largely retrieved from our previous and most recent work. PubMed and Google Scholar were searched for recent articles on the effect of macronutrients/dietary intake on inflammation, insulin resistance, obesity, and atherogenesis. The most relevant, high-quality articles were included in our review.

EVIDENCE SYNTHESIS

Our previous work has demonstrated the molecular mechanisms of macronutrient-mediated oxidative stress and inflammation. With the induction of inflammation, proinflammatory molecules potentially interfere with insulin signal transduction, thus causing insulin resistance. In addition, other molecules promote atherogenic inflammation. More recently, our work has also shown that certain foods are noninflammatory or anti-inflammatory and thus, do not interfere with insulin signaling. Finally, as obesity is induced by chronic excessive caloric intake, it is characterized by an increase in the expression of proinflammatory molecules, which are induced acutely by a Western diet. Caloric restriction, including fasting, is associated with a reduction in oxidative and inflammatory stress.

CONCLUSIONS

This review summarizes and attempts to provide an up-to-date profile of the molecular mechanisms involved in macronutrient-mediated oxidative/inflammatory stress and its potential consequences. An understanding of these underlying mechanisms is crucial for making appropriate dietary choices.

Hypertensive Heart Disease and Obesity: A Review

Metabolic syndrome is an increasingly prevalent constellation of disease processes among the global population. Hypertension and obesity are among the contributing etiologies, and obesity increases the likelihood of hypertensive heart disease by creating a proinflammatory state, as well as increasing sympathetic tone and formation of reactive oxygen species. Hypertensive heart disease is characterized by myocardial fibrosis, which portends higher risk of developing reduced ejection fraction, diastolic dysfunction, ischemia, and arrhythmias, making early diagnosis and treatment essential to the prevention of cardiac events.

Weight Loss and Hypertension in Obese Subjects

Arterial hypertension is strongly related to overweight and obesity. In obese subjects, several mechanisms may lead to hypertension such as insulin and leptin resistance, perivascular adipose tissue dysfunction, renal impairment, renin-angiotensin-aldosterone-system activation and sympathetic nervous system activity. Weight loss (WL) seems to have positive effects on blood pressure (BP). The aim of this review was to explain the mechanisms linking obesity and hypertension and to evaluate the main studies assessing the effect of WL on BP. We analysed studies published in the last 10 years (13 studies either interventional or observational) showing the effect of WL on BP. Different WL strategies were taken into account-diet and lifestyle modification, pharmacological intervention and bariatric surgery. Although a positive effect of WL could be identified in each study, the main difference seems to be the magnitude and the durability of BP reduction over time. Nevertheless, further follow-up data are needed: there is still a lack of evidence about long term effects of WL on hypertension. Hence, given the significant results obtained in several recent studies, weight management should always be pursued in obese patients with hypertension.

Elevated plasma endothelin-1 is associated with reduced weight loss post vertical sleeve gastrectomy

BACKGROUND

Obesity and insulin resistance are positively correlated with plasma endothelin-1 (ET-1) levels; however, the mechanisms leading to increased ET-1 are not understood. Similarly, the full physiological complexity of ET-1 has yet to be described, especially in obesity. To date, one of the best treatments available for morbid obesity is bariatric surgery to quickly reduce body fat and the factors associated with obesity-related disease; however, the effects of vertical sleeve gastrectomy (SG) on plasma ET-1 have not been described.

OBJECTIVES

To determine if SG will reduce plasma ET-1 levels and to determine if plasma ET-1 concentration is associated with weight loss after surgery.

SETTING

The studies were undertaken at a University Hospital.

METHODS

This was tested by measuring plasma ET-1 levels from 12 obese patients before and after SG. All data were collected from clinic visits before SG, 6 weeks after SG, and 6 months after surgery.

RESULTS

At 6 weeks after SG, plasma ET-1 levels increased by 24%; however, after 6 months, there was a 27% decrease compared with presurgery. Average weight loss in this cohort was 11.3% ± 2.4% body weight after 6 weeks and 21.4% ± 5.7% body weight after 6 months. Interestingly, we observed an inverse relationship between baseline plasma ET-1 and percent body weight loss (R² = .49, P = .01) and change in body mass index 6 months (R² = .45, P = .011) post bariatric surgery.

CONCLUSIONS

Our results indicate that SG reduces plasma ET-1 levels, a possible mechanism for improved metabolic risk in these patients. These data also suggest that ET-1 may serve as a predictor of weight loss after bariatric surgery.

Microvascular Endothelial Dysfunction in Human Obesity: Role of TNF-α

CONTEXT

Endothelium guarantees vascular homeostasis by the opposite action of substances by vasodilating/antithrombogenic and vasoconstricting/prothrombotic activities. Obesity is characterized by endothelial dysfunction associated with a condition of vascular low-grade inflammation.

EVIDENCE ACQUISITION

Analysis of available basic or clinical papers published in peer-reviewed international journals on microcirculation and obesity.

EVIDENCE SYNTHESIS

Vascular low-grade inflammation, which characterizes obesity, is secondary to abnormal production of proinflammatory cytokines, including TNF-α. TNF-α, generated either in small vessels or within the perivascular adipose tissue (PVAT) of patients with obesity, stimulates reactive oxygen species generation, mainly through NAD(P)H oxidase activation, which in turn reduces nitric oxide (NO) availability. These aspects are highlighted by the insulin resistance status and macronutrient intake that characterize the obesity condition. Oxidant excess has also been proposed as a mechanism whereby TNF-α interferes with the endothelin-1/NO system at the level of small vessels from patients with obesity.

CONCLUSIONS

In obesity, microvasculature from visceral fat is an important source of low-grade inflammation and oxidative stress that, together with the PVAT, directly contribute to vascular changes, favoring the development and acceleration of the vascular atherothrombotic process in this clinical condition.

The conundrum of patients with obesity, exercise intolerance, elevated ventricular filling pressures and a measured ejection fraction in the normal range

Patients with obesity, a reduced exercise capacity, increased cardiac filling pressures and a measured left ventricular ejection fraction in the normal range do not have a homogeneous disorder, but instead, exhibit one of three phenotypes. First, many obese people exhibit sodium retention, plasma volume expansion and cardiac enlargement, and some are likely to have heart failure that is related to hypervolaemia, even though cardiac index and circulating levels of natriuretic peptides are not meaningfully increased. Second, in some middle-aged men and women (particularly those with minimal co-morbidities), levels of natriuretic peptides increase markedly and can lower systemic vascular resistance, thus leading to high-output heart failure (HOHF) and glomerular hyperfiltration. Third, older obese people, particularly women with multiple co-morbidities, exhibit the syndrome of heart failure with a preserved ejection fraction (HFpEF). Despite degrees of plasma volume expansion similar to HOHF, these patients exhibit only modestly increased ventricular dimensions and circulating levels of natriuretic peptides (despite a high prevalence of atrial fibrillation), and glomerular function is characteristically impaired. A conceptual framework is proposed to distinguish among the three phenotypes seen in obese patients with exercise intolerance, increased ventricular filling pressures and a measured left ventricular ejection fraction in the normal range, since they may respond differently to therapeutic interventions. Efforts are needed to enhance the recognition of heart failure in obese people and to ensure that clinical trials that are designed to study patients with HFpEF actually enrol those who have the disease.