Metabolic syndrome is associated with abnormal left ventricular diastolic function independent of left ventricular mass

Sex-based differences in short- and longer-term diet-induced metabolic heart disease

Sex-based differences in the development of obesity-induced cardiometabolic dysfunction are well documented, however, the specific mechanisms are not completely understood. Obesity has been linked to dysregulation of the epitranscriptome, but the role of N6-methyladenosine (m6A) RNA methylation has not been investigated in relation to the sex differences during obesity-induced cardiac dysfunction. In the current study, male and female C57BL/6J mice were subjected to short- and long-term high-fat/high-sucrose (HFHS) diet to induce obesogenic stress. Cardiac echocardiography showed males developed systolic and diastolic dysfunction after 4 mo of diet, but females maintained normal cardiac function despite both sexes being metabolically dysfunctional. Cardiac m6A machinery gene expression was differentially regulated by duration of HFHS diet in male, but not female mice, and left ventricular ejection fraction correlated with RNA machinery gene levels in a sex- and age-dependent manner. RNA-sequencing of cardiac transcriptome revealed that females, but not males may undergo protective cardiac remodeling early in the course of obesogenic stress. Taken together, our study demonstrates for the first time that cardiac RNA methylation machinery genes are regulated early during obesogenic stress in a sex-dependent manner and may play a role in the sex differences observed in cardiometabolic dysfunction.NEW & NOTEWORTHY Sex differences in obesity-associated cardiomyopathy are well documented but incompletely understood. We show for the first time that RNA methylation machinery genes may be regulated in response to obesogenic diet in a sex- and age-dependent manner and levels may correspond to cardiac systolic function. Our cardiac RNA-seq analysis suggests female, but not male mice may be protected from cardiac dysfunction by a protective cardiac remodeling response early during obesogenic stress.

Prevalence and secular trends in premetabolic syndrome in the United States: Findings from 1999-2020 nationally representative data of adults

PURPOSE

Although Premetabolic syndrome (PeMetSyn) is a precursor for metabolic syndrome (MetSyn), its prevalence and trends are unknown. This study examined the prevalence and trends in PreMetSyn and its association with sociodemographic risk factors in American adults.

METHODS

The 1999-2000 to 2017-2020 United States National Health and Nutritional Health Surveys (NHANES) data were used. PreMetSyn was defined as co-occurrence two cardiometabolic risk factors consisting of abdominal obesity, elevated triglycerides, reduced HDL-C, elevated blood pressure, and fasting plasma glucose. We calculated sex-specific overall prevalence of PreMetSyn and by race/ethnicity, age, education, poverty, and body mass index (BMI) categories. Sex-specific logistic regression models were used to test the association between sociodemographic risk factors and PreMetSyn.

RESULTS

From 1999 - 2000 to 2017-2020, the age-adjusted overall prevalence of PreMetSyn increased by 155.4% (from 9.2% to 23.5%) in men and by 131.3% (from 11.2% to 25.9%) in women. Increases in prevalence of PreMetSyn were observed by race/ethnicity, age, education, poverty and BMI levels in men and women from 1999-2000 to 2017-2020. Survey cycle, race/ethnicity, age, education, poverty-income ratio, and BMI were independently associated with greater odds of PreMetSyn in males and females. During this period, the co-occurrence of abdominal obesity and elevated blood pressure was the most common comorbidity and increased from 20.6% to 30.8% in men and from 27.8% to 36.1% in women.

CONCLUSIONS

This nationally representative study indicates a rapid increase from 1999-2000 to 2017-2020 in the proportion of American adults who meet the criteria for PreMetSyn. Early identification of subjects with PreMetSyn in the U.S. is a public health priority for initiating effective strategies to prevent the development of MetSyn and its associated chronic diseases.

Plasma metabolic fingerprints for large-scale screening and personalized risk stratification of metabolic syndrome

Direct diagnosis and accurate assessment of metabolic syndrome (MetS) allow for prompt clinical interventions. However, traditional diagnostic strategies overlook the complex heterogeneity of MetS. Here, we perform metabolomic analysis in 13,554 participants from the natural cohort and identify 26 hub plasma metabolic fingerprints (PMFs) associated with MetS and its early identification (pre-MetS). By leveraging machine-learning algorithms, we develop robust diagnostic models for pre-MetS and MetS with convincing performance through independent validation. We utilize these PMFs to assess the relative contributions of the four major MetS risk factors in the general population, ranked as follows: hyperglycemia, hypertension, dyslipidemia, and obesity. Furthermore, we devise a personalized three-dimensional plasma metabolic risk (PMR) stratification, revealing three distinct risk patterns. In summary, our study offers effective screening tools for identifying pre-MetS and MetS patients in the general community, while defining the heterogeneous risk stratification of metabolic phenotypes in real-world settings.

Cardiac metabolism in HFpEF: from fuel to signalling

Heart failure (HF) is marked by distinctive changes in myocardial uptake and utilization of energy substrates. Among the different types of HF, HF with preserved ejection fraction (HFpEF) is a highly prevalent, complex, and heterogeneous condition for which metabolic derangements seem to dictate disease progression. Changes in intermediate metabolism in cardiometabolic HFpEF-among the most prevalent forms of HFpEF-have a large impact both on energy provision and on a number of signalling pathways in the heart. This dual, metabolic vs. signalling, role is played in particular by long-chain fatty acids (LCFAs) and short-chain carbon sources [namely, short-chain fatty acids (SCFAs) and ketone bodies (KBs)]. LCFAs are key fuels for the heart, but their excess can be harmful, as in the case of toxic accumulation of lipid by-products (i.e. lipotoxicity). SCFAs and KBs have been proposed as a potential major, alternative source of energy in HFpEF. At the same time, both LCFAs and short-chain carbon sources are substrate for protein post-translational modifications and other forms of direct and indirect signalling of pivotal importance in HFpEF pathogenesis. An in-depth molecular understanding of the biological functions of energy substrates and their signalling role will be instrumental in the development of novel therapeutic approaches to HFpEF. Here, we summarize the current evidence on changes in energy metabolism in HFpEF, discuss the signalling role of intermediate metabolites through, at least in part, their fate as substrates for post-translational modifications, and highlight clinical and translational challenges around metabolic therapy in HFpEF.

Endothelial cell-specific mineralocorticoid receptor activation promotes diastolic dysfunction in diet-induced obese male mice

Widespread consumption of diets high in fat and fructose (Western diet, WD) has led to increased prevalence of obesity and diastolic dysfunction (DD). DD is a prominent feature of heart failure with preserved ejection fraction (HFpEF). However, the underlying mechanisms of DD are poorly understood, and treatment options are still limited. We have previously shown that deletion of the cell-specific mineralocorticoid receptor in endothelial cells (ECMR) abrogates DD induced by WD feeding in female mice. However, the specific role of ECMR activation in the pathogenesis of DD in male mice has not been clarified. Therefore, we fed 4-wk-old ECMR knockout (ECMRKO) male mice and littermates (LM) with either a WD or chow diet (CD) for 16 wk. WD feeding resulted in DD characterized by increased left ventricle (LV) filling pressure (E/e') and diastolic stiffness [E/e'/LV inner diameter at end diastole (LVIDd)]. Compared with CD, WD in LM resulted in increased myocardial macrophage infiltration, oxidative stress, and increased myocardial phosphorylation of Akt, in concert with decreased phospholamban phosphorylation. WD also resulted in focal cardiomyocyte remodeling, characterized by areas of sarcomeric disorganization, loss of mitochondrial electron density, and mitochondrial fragmentation. Conversely, WD-induced DD and associated biochemical and structural abnormalities were prevented by ECMR deletion. In contrast with our previously reported observations in females, WD-fed male mice exhibited enhanced Akt signaling and a lower magnitude of cardiac injury. Collectively, our data support a critical role for ECMR in obesity-induced DD and suggest critical mechanistic differences in the genesis of DD between males and females.

Left ventricular diastolic dysfunction and cardiovascular disease in different ambient air pollution conditions: A prospective cohort study

Although previous studies indicated that the left ventricular diastolic dysfunction (LVDD) is associated with cardiovascular disease (CVD), it remains unclear whether effects would be enhanced or accelerated by long-term air pollution exposure. During 4.65 years (107,726 person-years) of follow-up, 942 cases of CVD events incident were identified among 23,143 participants from the China Hypertension Survey (CHS). Grading diastolic dysfunction was based on Recommendations for the evaluation of left ventricular diastolic function by echocardiography (2009). The annual average PM_2.5, PM₁₀ and NO₂ concentrations were obtained by the chemical data assimilation system. Cox proportional hazards models were employed to estimate hazard ratios (HRs) for CVD in relation to LVDD. At baseline, the participants' mean age was 56.7 years, 46.8% were male. Compared to normal group, the HR (95% CI) of LVDD was 1.27 (1.07-1.50) after adjusting for all covariates. When stratified by ambient air pollution, we found that in middle and worst third PM_2.5 areas, increased CVD risk was associated with increasing LVDD grade, both P for trend <0.05; The HRs (95% CI) of the CVD incidence were 1.52 (0.68-3.44), 4.97 (1.76-14.03) and 4.07 (1.44-11.49) for severe LVDD in the best, middle and worst third PM_2.5 areas, respectively. Similar results were also presented for PM₁₀ and NO₂. In conclusion, our study highlights a stronger detectable adverse association between LVDD with CVD in worse ambient air quality assessed by any of the three primary ambient air pollutants (PM_2.5, PM₁₀ and NO₂). Our study calls for appropriate interventions to reduce air pollution, which may promote great benefits to public health potentially by providing protection against the adverse CVD events.

Investigating the Relationship Between Cardiac Function and Insulin Sensitivity in Horses: A Pilot Study

Metabolic syndrome in humans is commonly associated with cardiovascular dysfunction, including atrial fibrillation and left ventricular diastolic dysfunction. Although many differences exist between human and equine metabolic syndrome, both of these conditions share some degree of insulin resistance. The aims of this pilot study were to investigate the relationship between insulin sensitivity and cardiac function. Seven horses (five mares, two geldings, aged 17.2 ± 4.2 years, weight 524 ± 73 kg) underwent insulin-modified frequently sampled intravenous glucose tolerance testing to determine insulin sensitivity (mean 2.21 ± 0.03 × 10−4 L/min/mU). Standard echocardiograms were performed on each horse, including two-dimensional, M-mode, and pulse-wave tissue Doppler imaging. Pearson and Spearman correlation analyses were used to determine the association of insulin sensitivity with echocardiographic measures of cardiac function in 5 horses. Insulin sensitivity was found to be significantly correlated with peak myocardial velocity during late diastole (r = 0.89, P = 0.0419), ratio between peak myocardial velocity in early and late diastole (r = −0.92, P = 0.0263), isovolumetric relaxation time (r = −0.97, P = 0.0072), and isovolumetric contraction time (ρ = −0.90, P = 0.0374). These preliminary data suggest that decreased insulin sensitivity is correlated with alterations in both systolic and diastolic function, as measured with tissue Doppler imaging (TDI). Due to the small sample size of this study, the relationship between insulin sensitivity and myocardial function in horses requires further investigation.

Association between metabolic syndrome and left ventricular geometric change including diastolic dysfunction

BACKGROUND

We investigated the association between individual components of metabolic syndrome (MetS) and left ventricular (LV) geometric changes, including diastolic dysfunction, in a large cohort of healthy individuals.

METHODS

Overall, 148 461 adults who underwent echocardiography during a health-screening program were enrolled. Geographic characteristics on echocardiography and several markers of LV relaxation function were identified according to individual MetS components. Univariate linear regression analysis and a multivariate regression model adjusted for factors known to influence LV relaxation function were conducted.

RESULTS

The prevalence of LV diastolic dysfunction (LVDD) was higher in the MetS group than in the non-MetS group (0.56% vs. 0.27%, p < .001). In univariate and multivariate analyses, E/A ratio, e' velocity, and left atrial volume index were significantly associated with each component of MetS and covariates (all p ≤ .001). In the age- and sex-adjusted model, MetS was significantly associated with LVDD (odds ratio [95% confidence interval], 1.350 [1.103, 1.652]). However, subjects with more MetS components did not have a significantly higher risk of LVDD. As the analysis was stratified by sex, the multivariate regression model showed that MetS was significantly associated with LVDD only in men (1.3 [1.00, 1.68]) with higher risk in more MetS component (p for trend < .001). In particular, triglyceride (TG) and waist circumference (WC) among MetS components were significantly associated with LVDD in men.

CONCLUSIONS

MetS was associated with the risk of LVDD, especially in men, with a dose-dependent association between an increasing number of components of MetS and LVDD. TG and WC were independent risk factors for LVDD in men.

Ellagic Acid Prevents Myocardial Infarction-induced Left Ventricular Diastolic Dysfunction in Ovariectomized Rats

Estrogen deficiency is associated with increased oxidative stress, which can contribute to left ventricular diastolic dysfunction (LVDD). We hypothesized that oral treatment with ellagic acid (EA), a potent and natural antioxidant compound, can improve MI-induced LVDD in ovariectomized rats, by reducing the formation of reactive oxygen species (ROS). Ovariectomized rats MI-induced LVDD followed by treatment with vehicle (DD) or EA (DD+EA) for 4 weeks. Non-LVDD-induced rats treated with vehicle (S) or EA (S+EA) were used as controls. Left ventricular systolic pressure: LVSP; left ventricular end-diastolic pressure: LVEDP; maximum rate of pressure rise: +dP/dt and fall: -dP/dt) were evaluated in all animals after treatment. Left ventricle superoxide anion formation was quantified in situ by fluorescence. Phospho-CAMKII, SOD2, catalase and gp91-phox abundances were evaluated by Western blot analyses. SOD and catalase activities were measured by spectrophotometry. The results showed that the LVEDP was significantly increased in both DD and DD+EA groups compared to S and S+EA. However, LVEDP in the DD+EA group was significantly decreased compared to DD, indicating an EA-mediated effect. In the DD group, superoxide production and gp91-phox protein abundance were increased while SOD2 abundance was decreased when compared to the S and S+EA groups. An increase in SOD activity was also observed in the DD+EA group. EA treatment reduced CaMKII phosphorylation in the DD+EA group compared to the DD. We concluded that EA treatment attenuated diastolic dysfunction in our experimental model, via reduction of ROS and CaMKII activity, indicating EA as a promising natural therapeutic option for cardiac dysfunction.

Lipotoxicity: a driver of heart failure with preserved ejection fraction?

Heart failure with preserved ejection fraction (HFpEF) is a growing public health concern, with rising incidence alongside high morbidity and mortality. However, the pathophysiology of HFpEF is not yet fully understood. The association between HFpEF and the metabolic syndrome (MetS) suggests that dysregulated lipid metabolism could drive diastolic dysfunction and subsequent HFpEF. Herein we summarise recent advances regarding the pathogenesis of HFpEF in the context of MetS, with a focus on impaired lipid handling, myocardial lipid accumulation and subsequent lipotoxicity.

Pre-Metabolic Syndrome and Incidence of Type 2 Diabetes and Hypertension: From the Korean Genome and Epidemiology Study

The aim of this study was to investigate the prevalence of premetabolic syndrome (pre-MetSyn) and its components and to longitudinally examine their association with new-onset type 2 diabetes (T2D) or hypertension. A total of 4037 men and 4400 women aged 40 to 69 years were selected from the Korean Genome and Epidemiology Study, observed from 2001 to 2014. Pre-MetSyn was defined as the presence of one or two components of MetSyn (B, elevated blood pressure; G, elevated glucose; H, low HDL-cholesterol; T, elevated triglycerides; W, increased waist circumference). The prevalence of pre-MetSyn was higher than that of non-MetSyn and MetSyn in both men and women. In multivariate Cox regression analyses, G, T, G+T, W+G, B+G, B+T, W+T, B+H, and H+T in men and G, T, G+H, B+T, and H+T in women were significantly associated with new-onset T2D. B, W, B+H, B+T, W+H, and W+T in men and B, B+T, B+H, B+W, and W+H in women were significantly associated with new-onset hypertension. The prevalence of pre-MetSyn components and their associations with new-onset T2D or hypertension differed according to sex and disease. Our results suggest that specific phenotypes of pre-MetSyn may be important factors for predicting and preventing the development of T2D and hypertension.

Effects of Sodium-Glucose Linked Transporter 2 Inhibition With Ertugliflozin on Mitochondrial Function, Energetics, and Metabolic Gene Expression in the Presence and Absence of Diabetes Mellitus in Mice

Background Inhibitors of the sodium-glucose linked transporter 2 improve cardiovascular outcomes in patients with or without type 2 diabetes mellitus, but the effects on cardiac energetics and mitochondrial function are unknown. We assessed the effects of sodium-glucose linked transporter 2 inhibition on mitochondrial function, high-energy phosphates, and genes encoding mitochondrial proteins in hearts of mice with and without diet-induced diabetic cardiomyopathy. Methods and Results Mice fed a control diet or a high-fat, high-sucrose diet received ertugliflozin mixed with the diet (0.5 mg/g of diet) for 4 months. Isolated mitochondria were assessed for functional capacity. High-energy phosphates were assessed by 31P nuclear magnetic resonance spectroscopy concurrently with contractile performance in isolated beating hearts. The high-fat, high-sucrose diet caused myocardial hypertrophy, diastolic dysfunction, mitochondrial dysfunction, and impaired energetic response, all of which were prevented by ertugliflozin. With both diets, ertugliflozin caused supernormalization of contractile reserve, as measured by rate×pressure product at high work demand. Likewise, the myocardial gene sets most enriched by ertugliflozin were for oxidative phosphorylation and fatty acid metabolism, both of which were enriched independent of diet. Conclusions Ertugliflozin not only prevented high-fat, high-sucrose-induced pathological cardiac remodeling, but improved contractile reserve and induced the expression of oxidative phosphorylation and fatty acid metabolism gene sets independent of diabetic status. These effects of sodium-glucose linked transporter 2 inhibition on cardiac energetics and metabolism may contribute to improved structure and function in cardiac diseases associated with mitochondrial dysfunction, such as heart failure.

Elevated Plasma Homocysteine Level Associated with Further Left Ventricular Structure and Function Damages in Type 2 Diabetic Patients: A Three-Dimensional Speckle Tracking Echocardiography Study

Aims: The aims of this study were to explore the left ventricular (LV) structural remodeling and its risk factors in type 2 diabetes mellitus (T2DM) patients with or without hyperhomocysteinemia (hHcy) and to detect the accompanied LV dysfunction using three-dimensional speckle tracking echocardiography (3DSTE). Methods: There were totally 80 T2DM patients with undamaged LV ejection fraction (≥55%) in this study, 40 of whom were also diagnosed with hHcy as co-morbidity. Forty age- and gender-matched controls were also recruited. The risk factors and corresponding diagnostic values for LV remodeling (LVR) were, respectively, determined using logistic regression and area under the receiver operating characteristic curves (AUC). The 3DSTE was used to measure global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS). Results: The constituent ratio of LV geometry showed significant differences among the study populations (P = 0.01). Compared with the controls, three types of LVR accounted for larger proportion in the two T2DM groups, whereas LV hypertrophy was most prevalent in those with T2DM and hHcy. Glycosylated hemoglobin (HbA1c), total plasma homocysteine (tHcy), and HbA1c plus tHcy were all significant risk factors associated with LVR in T2DM patients (AUC values: 0.741, 0.746 and 0.851, respectively). The patients with T2DM alone had significantly lower GLS and GAS than the controls (both P < 0.05). The patients with T2DM and hHcy had significantly lower GLS, GCS, GAS, and GRS than the controls (all P < 0.001), and also had significantly lower GLS, GCS, and GRS than the patients with T2DM alone (all P < 0.05). Conclusions: The 3DSTE plus conventional echocardiography could be used as an effective supplement for detecting early and occult cardiac damages in T2DM patients with plasma homocysteine at normal or elevated levels.

Metformin in non-diabetic patients with metabolic syndrome and diastolic dysfunction: the MET-DIME randomized trial

PURPOSE

Metabolic syndrome (MetS) affects one out of 3 adults in the western world and is associated with preclinical diastolic dysfunction that impairs functional capacity and quality of life (QoL). This randomized trial was designed to evaluate if the addition of metformin to the standard treatment of non-diabetic patients with MetS improves diastolic dysfunction.

METHODS

Prospective, randomized, open-label, blinded-endpoint trial. Fifty-four non-diabetic adults with MetS and diastolic dysfunction were randomized to lifestyle counseling or lifestyle counseling plus metformin (target dose 1000 mg bid). The primary endpoint was the change in mean e' velocity (assessed at baseline, 6, 12 and 24 months). Secondary endpoints were improvements in insulin resistance, functional capacity and QoL. Linear mixed effects modeling was used for longitudinal data analysis using modified intention-to-treat (mITT) and per-protocol (PP) approaches.

RESULTS

Forty-nine patients were included in the mITT analysis (mean age = 51.8 ± 6.4; 55% males). Metformin treatment was associated with a significant decrease in HOMA-IR. There was a significantly different mean change in e' velocity during the study period between trial arms, both in the mITT (at 24 months, change of +0.67 ± 1.90 cm/s in metformin arm vs. -0.33 ± 1.50 cm/s in control arm) and PP populations (+0.80 ± 1.99 cm/s in metformin arm vs. -0.37 ± 1.52 cm/s in control arm), using a random intercept linear mixed model. There were no significant differences in peak oxygen uptake and SF-36 scores between trial arms.

CONCLUSIONS

Treatment with metformin of non-diabetic MetS patients with diastolic dysfunction, on top of lifestyle counseling, is associated with improved diastolic function.

Famoxadone-cymoxanil induced cardiotoxicity in zebrafish embryos

Famoxadone-cymoxanil is a new protective and therapeutic fungicide, but little research has been done on it or its toxicity in aquatic organisms. In this study, we used zebrafish to investigate the cardiotoxicity of famoxadone-cymoxanil and the potential mechanisms involved. Zebrafish embryos were exposed to different concentrations of famoxadone-cymoxanil until 72 h post-fertilization (hpf), then changes of heart morphology in zebrafish embryos were observed. We also detected the levels of oxidative stress, myocardial-cell proliferation and apoptosis, ATPase activity, and the expression of genes related to the cardiac development and calcium-signaling pathway. After famoxadone-cymoxanil exposure, pericardial edema, cardiac linearization, and reductions in the heart rate and cardiac output positively correlated with concentration. Although myocardial-cell apoptosis was not detected, proliferation of the cells was severely reduced and ATPase activity significantly decreased, resulting in a severe deficiency in heart function. In addition, indicators of oxidative stress changed significantly after exposure of the embryos to the fungicide. To better understand the possible molecular mechanisms of cardiovascular toxicity in zebrafish, we studied the transcriptional levels of cardiac development, calcium-signaling pathways, and genes associated with myocardial contractility. The mRNA expression levels of key genes in heart development were significantly down-regulated, while the expression of genes related to the calcium-signaling pathway (ATPase [atp2a1], cardiac troponin C [tnnc1a], and calcium channel [cacna1a]) was significantly inhibited. Expression of klf2a, a major endocardial flow-responsive gene, was also significantly inhibited. Mechanistically, famoxadone-cymoxanil toxicity might be due to the downregulation of genes associated with the calcium-signaling pathway and cardiac muscle contraction. Our results found that famoxadone-cymoxanil exposure causes cardiac developmental toxicity and severe energy deficiency in zebrafish.

Differential Effects of Sacubitril/Valsartan on Diastolic Function in Mice With Obesity-Related Metabolic Heart Disease

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MHD associated with obesity, diabetes, and/or metabolic syndrome is an important precursor of HFpEF.

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Mice fed a HFHS diet develop MHD with myocardial hypertrophy, fibrosis, diastolic dysfunction, and impaired energetics.

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Mice on HFHS diet were treated with matched doses of VAL or sac SAC/VAL for 16 weeks.

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Only SAC/VAL prevented diastolic dysfunction and fibrosis, and to a lesser extent oxidative stress, whereas VAL and SAC/VAL had similar effects on hypertrophy and energetics.

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Neprilysin inhibition exerts beneficial effects on MHD that are complimentary to VAL, suggesting that SAC/VAL has promise to prevent the development of HFpEF in patients with or at risk for MHD.

Mice with obesity and metabolic heart disease (MHD) due to a high-fat, high-sucrose diet were treated with placebo, a clinically relevant dose of sacubitril (SAC)/valsartan (VAL), or an equivalent dose of VAL for 4 months. There were striking differences between SAC/VAL and VAL with regard to: 1) diastolic dysfunction; 2) interstitial fibrosis; and to a lesser degree; 3) oxidative stress—all of which were more favorably affected by SAC/VAL. SAC/VAL and VAL similarly attenuated myocardial hypertrophy and improved myocardial energetics. In mice with obesity-related MHD, neprilysin inhibition exerts favorable effects on diastolic function.

The association of the metabolic syndrome with target organ damage: focus on the heart, brain, and central arteries

INTRODUCTION

The metabolic syndrome (MetS) is an adverse metabolic state composed of obesity, hyperglycemia/pre-diabetes, hypertension, and dyslipidemia. It substantially increases the risk of type 2 diabetes, cardiovascular disease (CVD) and mortality, and has a huge impact on public health.

AREA COVERED

The present review gives an update on the definition and prevalence of MetS, and its impact on cardiac structure and function as well as on the brain and central arteries. The association with CVD and mortality risk is discussed. Focus is mainly directed toward the subclinical target organ damage related to MetS. Data is also critically reviewed to provide evidence on the incremental prognostic value of overall MetS over its individual components.

EXPERT COMMENTARY

MetS is a clinical risk condition associated with subclinical and clinical CVD and mortality. Roughly, 30% of the world population suffer from MetS. As all components of the MetS are modifiable, optimal preventive and therapeutic measures should be initiated to improve CV risk control, particularly aggressively treating hypertension and hyperglycemia, and encouraging people to adopt healthy lifestyle as early as possible is of great importance.

Metabolic Risk Factors and Left Ventricular Diastolic Function in Middle-Aged Chinese Living in the Tibetan Plateau

Background

Data regarding the metabolic risk factors clustering on the risk of left ventricular diastolic dysfunction (LVDD) are lacking among people living at high altitude and under hypoxic conditions. In this study, we explored the association between metabolic risk factor clustering and LVDD among the Tibetan population of China.

Methods and Results

We conducted a cross‐sectional survey in a representative sample of 1963 Tibetans in 2014 to 2016. Grading LVDD was based on recommendations for the evaluation of LV diastolic function by echocardiography (2009). The prevalence of LVDD among 1963 participants (mean age: 51.51 years, 41.11% male) was 34.39%. Odds ratios (95% CI) of LVDD for the 1, 2, and 3 to 5 risk factors clustering were 1.45 (0.96–2.17), 2.68 (1.8–3.98), and 2.9 (1.9–4.43), respectively (P for trend <0.001). The association between metabolic risk factors clustering and LVDD was much more pronounced in the middle‐aged group than in the elderly (P for interaction=0.0170). High altitude was one of the major independent risk factors for LVDD; however, habitation altitude had no significant effect on the association between metabolic risk factors and LVDD (P for interaction=0.1022). The multivariable dominance analysis indicated that abdominal obesity, hypertension, and elevated blood glucose were the significant contributors to LVDD.

Conclusions

There was a significant positive association between the metabolic risk factor clustering number and LVDD among a population living at high altitude, especially in middle‐aged adults. However, habitation altitude itself has no significant effect on the association between metabolic risk factors and LVDD.

Impact of Recreational Sports Activities on Metabolic Syndrome Components in Adolescents

We investigated the impact of a sports activities program on metabolic syndrome (MetS) components and pre-MetS among adolescents. Blood samples, blood pressure, weight, height, body mass index, waist circumference, body fat percentage, frequency of food consumption, daily time in moderate-to-vigorous physical activity (MVPA), and sedentary behavior (SB) of 92 male adolescents aged 14-18 years (16.07 ± 0.93) were evaluated. From this initial sample, 36 participants (39.1%) were diagnosed with pre-MetS or MetS and were invited to participate in the intervention program. Twelve individuals diagnosed with pre-MetS or MetS agreed to participate in a recreational sports activities program lasting 14 weeks. The pre- and post-sport program comparison showed a reduction in total cholesterol, low-density lipoprotein, and non-high-density lipoprotein (HDL), and an increase in HDL and MVPA time in the intervention group. Sports activities accounted for 42% of the MVPA daily recommendation, and at the end of the intervention period, only seven subjects maintained a positive diagnosis for pre-MetS or MetS. This study showed that recreational sports activities had a significant impact on the lipid profile.

Exercise Training Promotes Cardiac Hydrogen Sulfide Biosynthesis and Mitigates Pyroptosis to Prevent High-Fat Diet-Induced Diabetic Cardiomyopathy

Obesity increases the risk of developing diabetes and subsequently, diabetic cardiomyopathy (DMCM). Reduced cardioprotective antioxidant hydrogen sulfide (H₂S) and increased inflammatory cell death via pyroptosis contribute to adverse cardiac remodeling and DMCM. Although exercise training (EX) has cardioprotective effects, it is unclear whether EX mitigates obesity-induced DMCM by increasing H₂S biosynthesis and mitigating pyroptosis in the heart. C57BL6 mice were fed a high-fat diet (HFD) while undergoing treadmill EX for 20 weeks. HFD mice developed obesity, hyperglycemia, and insulin resistance, which were reduced by EX. Left ventricle pressure-volume measurement revealed that obese mice developed reduced diastolic function with preserved ejection fraction, which was improved by EX. Cardiac dysfunction was accompanied by increased cardiac pyroptosis signaling, structural remodeling, and metabolic remodeling, indicated by accumulation of lipid droplets in the heart. Notably, EX increased cardiac H₂S concentration and expression of H₂S biosynthesis enzymes. HFD-induced obesity led to features of type 2 diabetes (T2DM), and subsequently DMCM. EX during the HFD regimen prevented the development of DMCM, possibly by promoting H₂S-mediated cardioprotection and alleviating pyroptosis. This is the first report of EX modulating H₂S and pyroptotic signaling in the heart.

Energetic Dysfunction Is Mediated by Mitochondrial Reactive Oxygen Species and Precedes Structural Remodeling in Metabolic Heart Disease

Aims: Metabolic syndrome is associated with metabolic heart disease (MHD) that is characterized by left ventricular (LV) hypertrophy, interstitial fibrosis, contractile dysfunction, and mitochondrial dysfunction. Overexpression of catalase in mitochondria (transgenic expression of catalase targeted to the mitochondria [mCAT]) prevents the structural and functional features of MHD caused by a high-fat, high-sucrose (HFHS) diet for ≥4 months. However, it is unclear whether the effect of mCAT is due to prevention of reactive oxygen species (ROS)-mediated cardiac remodeling, a direct effect on mitochondrial function, or both. To address this question, we measured myocardial function and energetics in mice, with or without mCAT, after 1 month of HFHS, before the development of cardiac structural remodeling. Results: HFHS diet for 1 month had no effect on body weight, heart weight, LV structure, myocyte size, or interstitial fibrosis. Isolated cardiac mitochondria from HFHS-fed mice produced 2.2- to 3.8-fold more H2O2, and 16%-29% less adenosine triphosphate (ATP). In isolated beating hearts from HFHS-fed mice, [phosphocreatine (PCr)] and the free energy available for ATP hydrolysis (ΔG∼ATP) were decreased, and they failed to increase with work demands. Overexpression of mCAT normalized ROS and ATP production in isolated mitochondria, and it corrected myocardial [PCr] and ΔG∼ATP in the beating heart. Innovation: This is the first demonstration that in MHD, mitochondrial ROS mediate energetic dysfunction that is sufficient to impair contractile function. Conclusion: ROS produced and acting in the mitochondria impair myocardial energetics, leading to slowed relaxation and decreased contractile reserve. These effects precede structural remodeling and are corrected by mCAT, indicating that ROS-mediated energetic impairment, per se, is sufficient to cause contractile dysfunction in MHD.

Hypoxia-inducible factor 1-alpha (HIF-1α) as a factor mediating the relationship between obesity and heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF), a common condition with an increased mortality, is strongly associated with obesity and the metabolic syndrome. The latter two conditions are associated with increased epicardial fat that can extend into the heart. This review advances the proposition that hypoxia-inhibitory factor-1α (HIF-1α) maybe a key factor producing HFpEF. HIF-1α, a highly conserved transcription factor that plays a key role in tissue response to hypoxia, is increased in adipose tissue in obesity. Increased HIF-1α expression leads to expression of a potent profibrotic transcriptional programme involving collagen I, III, IV, TIMP, and lysyl oxidase. The net effect is the formation of collagen fibres leading to fibrosis. HIF-1α is also responsible for recruiting M1 macrophages that mediate obesity-associated inflammation, releasing IL-6, MCP-1, TNF-α, and IL-1β with increased expression of thrombospondin, pro α2 (I) collagen, transforming growth factor β, NADPH oxidase, and connective tissue growth factor. These factors can accelerate cardiac fibrosis and impair cardiac diastolic function. Inhibition of HIF-1α expression in adipose tissue of mice fed a high-fat diet suppressed fibrosis and reduces inflammation in adipose tissue. Delineation of the role played by HIF-1α in obesity-associated HFpEF may lead to new potential therapies.

Right ventricular dysfunction and remodeling in diabetic cardiomyopathy

The increasing prevalence of diabetic cardiomyopathy (DCM) is an important threat to health worldwide. While left ventricular (LV) dysfunction in DCM is well recognized, the accurate detection, diagnosis, and treatment of changes in right ventricular (RV) structure and function have not been well characterized. The pathophysiology of RV dysfunction in DCM may share features with LV diastolic and systolic dysfunction, including pathways related to insulin resistance and oxidant injury, although the RV has a unique cellular origin and composition and unique biomechanical properties and is coupled to the lower-impedance pulmonary vascular bed. In this review, we discuss potential mechanisms responsible for RV dysfunction in DCM and review the imaging approaches useful for early detection, protection, and intervention strategies. Additional data are required from animal models and clinical trials to better identify the onset and features of altered RV and pulmonary vascular structure and function during the onset and progression of DCM and to determine the efficacy of early detection and treatment of RV dysfunction on clinical symptoms and outcomes.

Effects of multiparity on left ventricular diastolic dysfunction in women: cross-sectional study of the KoRean wOmen'S chest pain rEgistry (KoROSE)

OBJECTIVES

To investigate the association between left ventricular (LV) diastolic dysfunction and multiparity in patients with suspected coronary artery disease (CAD).

DESIGN

Cross-sectional study.

SETTING

Linked secondary and tertiary care records from 29 cardiac centres which participated in KoRean wOmen'S chest pain rEgistry.

PARTICIPANTS

960 women with suspected CAD who underwent invasive coronary angiography from February 2011 to May 2017. The patients were classified by parity number, as follows: low-parity, 0 to <3; multiparity, ≥3 pregnancies.

MAIN OUTCOME MEASURE

Prevalence of LV diastolic dysfunction.

RESULTS

There were 302 and 658 low-parity and multiparity patients, respectively. The prevalence of LV diastolic dysfunction was significantly higher in the multiparity than in the low-parity group. The multiparity group had significantly lower E and e´ septal velocities and E/A ratio, and had a significantly higher E/e´ ratio and right ventricular systolic pressure, which are parameters of LV diastolic dysfunction, than the low-parity group. The prevalence of CAD was significantly higher in the multiparity than in the low-parity group. Receiver operating characteristic curve analysis identified a parity of 2.5 as the cut-off for predicting LV diastolic dysfunction (area under the curve, 0.66; sensitivity, 74.1%; specificity, 52.0%; 95% CI 0.607 to 0.706; p<0.001). After adjustment for confounding factors, multivariate regression analysis showed that multiparity had a 1.80-fold increased risk for LV diastolic dysfunction (OR 1.80, 95% CI 1.053 to 3.081, p=0.032).

CONCLUSIONS

The prevalence of LV diastolic dysfunction was higher in multiparity than in low-parity women with suspected CAD. Multiparity was an independent risk factor for LV diastolic dysfunction. LV diastolic dysfunction should be evaluated in multiparous women for the risk of subsequent cardiovascular disease and facilitate the initiation of appropriate treatment.

Adverse physiologic effects of Western diet on right ventricular structure and function: role of lipid accumulation and metabolic therapy

Little is known about the impact of metabolic syndrome (MS) on right ventricular (RV) structure and function. We hypothesized that mice fed a Western diet (WD) would develop RV lipid accumulation and impaired RV function, which would be ameliorated with metformin. Male C57/Bl6 mice were fed a WD or standard rodent diet (SD) for eight weeks. A subset of mice underwent pulmonary artery banding (PAB). Treated mice were given 2.5 g/kg metformin mixed in food. Invasive hemodynamics, histology, Western, and quantitative polymerase chain reaction (qPCR) were performed using standard techniques. Lipid content was detected by Oil Red O staining. Mice fed a WD developed insulin resistance, RV hypertrophy, and higher RV systolic pressure compared with SD controls. Myocardial lipid accumulation was greater in the WD group and disproportionately affected the RV. These structural changes were associated with impaired RV diastolic function in WD mice. PAB-WD mice had greater RV hypertrophy, increased lipid deposition, and lower RV ejection fraction compared with PAB SD controls. Compared to untreated mice, metformin lowered HOMA-IR and prevented weight gain in mice fed a WD. Metformin reduced RV systolic pressure, prevented RV hypertrophy, and reduced RV lipid accumulation in both unstressed stressed conditions. RV diastolic function improved in WD mice treated with metformin. WD in mice leads to an elevation in pulmonary pressure, RV diastolic dysfunction, and disproportionate RV steatosis, which are exacerbated by PAB. Metformin prevents the deleterious effects of WD on RV function and myocardial steatosis in this model of the metabolic syndrome.

Association of central obesity with sex hormonebinding globulin: a cross-sectional study of 1166 Chinese men

Background Both sex hormone-binding globulin and central obesity have been found to be associated with metabolic and cardiovascular diseases. However, the direct relation between sex hormone-binding globulin and central obesity has not been demonstrated.

Methodology We performed a cross-sectional study of 1166 male participants from Zunyi, Guizhou, western China, in 2013. Each participant completed a questionnaire and had a brief clinical exam with a fasting blood sample taken. All blood samples underwent standard laboratory testing for sex hormone-binding globulin. Level of serum sex hormone-binding globulin was compared by demographic characteristics, and multiple linear regression was used to evaluate the independent association of variables and sex hormone-binding globulin level.

Results The mean serum level of sex hormone-binding globulin was increased in old-aged men (older than 40 years; mean 44.68±20.58 nmol/L), low diastolic blood pressure (<90mmHg; 43.76±20.50 nmol/L), waist-to-height ratio <0.5 (48.73±20.59 nmol/L), no education (52.36±22.91 nmol/L), farm occupation (43.58±20.60nmol/L), non-alcohol or former user (44.78±20.94 nmol/L) and long-term medication history (44.79±21.50 nmol/L). Factors independently associated with sex hormone binding globulin level on multiple regression were waist-to-height ratio (β=- 11.84 [95% confidence interval -13.96,-9.72]), age(β=12.40 [9.63,15.17]) and diastolic blood pressure (β=-5.07 [-7.44,-2.71]).

Conclusions Central obesity has an independent inverse relation with serum level of sex hormone binding globulin among western Chinese men

Obesity and metabolic features associated with long-term developing diastolic dysfunction in an initially healthy population-based cohort

BACKGROUND

Diastolic dysfunction (DD) is increasingly common. However, its metabolic determinants are poorly known. This study aims to determine which metabolic and inflammatory features predict DD in initially healthy adults.

METHODS

We prospectively analyzed the association between metabolic features and DD in 728 initially healthy adults aged 30-60 from Eastern France enrolled in the STANISLAS population-based cohort. Clinical and biological cardiovascular features were collected at baseline (1994-1995). DD was assessed twenty years later (2011-2016) by echocardiography using current international guidelines. For replication purposes, 1463 subjects from the Malmö Preventive Project cohort were analyzed.

RESULTS

In the STANISLAS cohort, 191 subjects (26.2%) developed DD. In age-sex-adjusted logistic models, significant predictors of DD were body mass index (BMI, odds ratio for 1-standard-deviation increase (OR) 1.28, 95% CI 1.08-1.52), waist circumference (WC, OR 1.48, 95% CI 1.18-1.84), waist-hip ratio (OR 1.53, 95% CI 1.16-2.02), systolic blood pressure (OR 1.19, 95% CI 1.00-1.43) and triglycerides (TG, OR 1.18, 95% CI 1.00-1.40). Subjects with elevated WC (> 80th percentile) and TG (> 50th percentile) had a twofold higher DD risk (age-sex-adjusted odds ratio 2.00, 95% CI 1.20-3.31, P = 0.008), whereas no such interplay was observed for BMI. In the Malmö cohort, BMI was similarly associated with DD; participants with both elevated BMI and TG were at higher DD risk (age-sex-adjusted odds ratio 1.61, 95% CI 1.18-2.20, P = 0.002).

CONCLUSIONS

Subjects with elevated WC and TG may have a higher long-term DD risk. Prevention targeting visceral obesity may help reduce the incidence of DD.

Cardiovascular Risk in Patients with Prehypertension and the Metabolic Syndrome

Prehypertension (pHTN) and metabolic syndrome (MetS) are both lifestyle diseases that are potentiated by increased adiposity, as both disease processes are closely related to weight. In the case of pHTN, increased adiposity causes dysregulation of the renin-angiotensin-aldosterone-system (RAAS) as well as adipokine- and leptin-associated increases in adrenergic tone. In MetS, excess weight potentiates hyperglycemia and insulin resistance which causes positive feedback into the RAAS system, activates an inflammatory cascade that potentiates atherosclerosis, and causes lipid dysregulation which together contribute to cardiovascular disease, especially coronary heart disease (CHD) and heart failure (HF). The relationship with all-cause mortality is not as clear-cut in part because of some protective effects associated with the obesity paradox in chronic diseases such as CHD and HF. However, in healthy populations, the absence of excess weight and its associated effects on prehypertension and MetS are associated with a longer absolute and disease-free lifespan.

Association of Age at Menarche With Left Ventricular Diastolic Dysfunction in Middle-Aged Women

BACKGROUND

There is sparse research on whether if early menarche is related to left ventricular (LV) diastolic dysfunction. The present study examined this relationship in Korean women.Methods and Results:In a cross-sectional study we analyzed the records of 18,910 Korean women (≥30 years) who underwent echocardiography as part of a comprehensive health examination. Age at menarche was assessed using standardized, self-administered questionnaires. Presence of LV diastolic dysfunction was determined from the echocardiographic findings. Of the 18,910 women, 3,449 had LV diastolic dysfunction. Age at menarche was inversely associated with prevalence of LV diastolic dysfunction. In a multivariable-adjusted model, odds ratios (95% confidence interval) for LV diastolic dysfunction comparing menarche age to menarche at 15-18 years were 1.77 (1.38-2.27) for <12 years, 1.31 (1.11-1.54) for 12 years, 1.26 (1.11-1.43) for 13 years, and 1.03 (0.91-1.15) for 14 years (P for trend <0.001). Adjusting for body mass index or percent fat mass partially reduced these associations.

CONCLUSIONS

This large study found an inverse relationship between menarche age and LV diastolic dysfunction. Future prospective studies are needed to investigate potential causal relationships.

Decreased ATP production and myocardial contractile reserve in metabolic heart disease

Metabolic syndrome is a cluster of obesity-related metabolic abnormalities that lead to metabolic heart disease (MHD) with left ventricular pump dysfunction. Although MHD is thought to be associated with myocardial energetic deficiency, two key questions have not been answered. First, it is not known whether there is a sufficient energy deficit to contribute to pump dysfunction. Second, the basis for the energy deficit is not clear. To address these questions, mice were fed a high fat, high sucrose (HFHS) ‘Western’ diet to recapitulate the MHD phenotype. In isolated beating hearts, we used ³¹P NMR spectroscopy with magnetization transfer to determine a) the concentrations of high energy phosphates ([ATP], [ADP], [PCr]), b) the free energy of ATP hydrolysis (ΔG_~ATP), c) the rate of ATP production and d) flux through the creatine kinase (CK) reaction. At the lowest workload, the diastolic pressure-volume relationship was shifted upward in HFHS hearts, indicative of diastolic dysfunction, whereas systolic function was preserved. At this workload, the rate of ATP synthesis was decreased in HFHS hearts, and was associated with decreases in both [PCr] and ΔG_~ATP. Higher work demands unmaske^d the inability of HFHS hearts to increase systolic function and led to a further decrease in ΔG_~ATP to a level that is not sufficient to maintain normal function of sarcoplasmic Ca²⁺-ATPase (SERCA). While [ATP] was preserved at all work demands in HFHS hearts, the progressive increase in [ADP] led to a decrease in ΔG_~ATP with increased work demands. Surprisingly, CK flux, CK activity and total creatine were normal in HFHS hearts. These findings differ from dilated cardiomyopathy, in which the energetic deficiency is associated with decreases in CK flux, CK activity and total creatine. Thus, in HFHS-fed mice with MHD there is a distinct metabolic phenotype of the heart characterized by a decrease in ATP production that leads to a functionally-important energetic deficiency and an elevation of [ADP], with preservation of CK flux.

Multimarker Assessment of Diastolic Dysfunction in Metabolic Syndrome Patients

BACKGROUND

Metabolic syndrome (MetS) has been associated with left ventricular diastolic dysfunction (LVDD) with preserved systolic function. This study aims at identifying the predictive factors for LVDD in MetS patients.

METHODS

The studied group comprised 72 consecutive hospitalized patients (2010-2011) diagnosed with MetS based on AHA/NHLBI/IDF 2009 definition, free of cardiovascular disease (36.11% males, age 59.19 ± 5.26 years), who underwent echocardiographic examination. Laboratory measurements of high-sensitivity C-reactive protein (hs-CRP), fibrinogen (Fbg) and interleukin-6 (IL-6), 8-isoprostaglandin-F2alpa (8-isoPGF2α), uric acid, glutathione peroxidases, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were measured.

RESULTS

LVDD was identified in 47 (65.27%) of the MetS patients. The diastolic blood pressure (DBP) was the strongest prediction factor for LVDD (areas under the receiver operating curve [AUC]: 0.73, odds ratios [OR]: 1.065). The number of MetS criteria was also significantly predictive for LVDD (AUC: 0.65, OR: 2.029, P < 0.04). IL-6, hs-CRP, Fbg, and NT-proBNP were predictive for LVDD when receiver operating curve (ROC) analyses were used. The multimarker model comprising age, sex, SBP and DBP, waist, circumference, triglycerides along with hs-CRP, IL-6, and NT-proBNP had the best predictive capacity (AUC: 0.88, P = 0.0001). In multivariate analysis, IL-6 remained an independent predictive biomarker for LVDD (OR: 2.045).

CONCLUSION

Both MetS components and biomarkers of inflammation (IF) are predictive factors for LVDD. The best predictive multimarker model for LVDD in MetS patients is composed of waist, triglycerides (TGL), SBP, DBP, fasting glucose, IL-6, hs-CRP, and NT-proBNP. IL-6 remains an independent predictive biomarker for LVDD in MetS patients, underlining the importance of IF in the evolution of MetS to subclinical cardiac damage.

Soluble ST2 Levels and Left Ventricular Structure and Function in Patients With Metabolic Syndrome

BACKGROUND

A biomarker that is of great interest in relation to adverse cardiovascular events is soluble ST2 (sST2), a member of the interleukin family. Considering that metabolic syndrome (MetS) is accompanied by a proinflammatory state, we aimed to assess the relationship between sST2 and left ventricular (LV) structure and function in patients with MetS.

METHODS

A multicentric, cross-sectional study was conducted on180 MetS subjects with normal LV ejection fraction as determined by echocardiography. LV hypertrophy (LVH) was defined as an LV mass index greater than the gender-specific upper limit of normal as determined by echocardiography. LV diastolic dysfunction (DD) was assessed by pulse-wave and tissue Doppler imaging. sST2 was measured by using a quantitative monoclonal ELISA assay.

RESULTS

LV mass index (β=0.337, P<0.001, linear regression) was independently associated with sST2 concentrations. Increased sST2 was associated with an increased likelihood of LVH [Exp (B)=2.20, P=0.048, logistic regression] and increased systolic blood pressure [Exp (B)=1.02, P=0.05, logistic regression]. Comparing mean sST2 concentrations (adjusted for age, body mass index, gender) between different LV remodeling patterns, we found the greatest sST2 level in the group with concentric hypertrophy. There were no differences in sST2 concentration between groups with and without LV DD.

CONCLUSIONS

Increased sST2 concentration in patients with MetS was associated with a greater likelihood of exhibiting LVH. Our results suggest that inflammation could be one of the principal triggering mechanisms for LV remodeling in MetS.

Relationship between Metabolic Syndrome and Ocular Microcirculation Shown by Laser Speckle Flowgraphy in a Hospital Setting Devoted to Sleep Apnea Syndrome Diagnostics

PURPOSE

To clarify whether the incidence of metabolic syndrome (MetS) and the overlap of MetS components are affecting the ocular circulation shown by laser speckle flowgraphy (LSFG).

MATERIALS AND METHODS

We studied 76 consistent patients. Blowout score (BOS) and blowout time (BOT), which are the pulse waveform analysis parameters, and mean blur rate (MBR) using LSFG in the optic nerve head (ONH) and choroid were evaluated. Throughout, the ONH was separated out from the vessels and tissue for analysis and MBRs in the ONH were divided into four sections (superior, temporal, inferior, and nasal).

RESULTS

Thirty-two patients were diagnosed having Mets. MBR-Tissue (P = 0.003), MBR-All (P = 0.01), MBR-Choroid (P = 0.04), and BOS-Choroid (P = 0.03) were significantly lower in patients with MetS than in the patients without MetS. Multiple-regression analysis revealed the temporal side of MBR-Tissue and BOS-Choroid which were identified as factors contributing independently to the overlap of the MetS components. Multiple-regression analysis also revealed that the MetS components were identified to be factors independently contributing to the BOS-Choroid and temporal side of MBR-Tissue.

CONCLUSION

Our study clarified that the incidence of MetS and the overlap of the MetS components are significantly affecting the ONH and choroidal microcirculation.

Insulin resistance-associated decreases in left ventricular diastolic function are strongly modified by the extent of concentric remodeling in a community sample

BACKGROUND

Whether excess adiposity, associated metabolic abnormalities or alternative risk factors for left ventricular (LV) diastolic function are modified rather than mediated by geometric LV remodeling, is uncertain.

METHODS

Echocardiographic LV mass index (LVMI), relative wall thickness (RWT) and diastolic function (lateral and septal wall myocardial tissue lengthening at the level of the mitral annulus [e'] [n=430], ratio of early-to-late transmitral blood flow velocity (E/A), and E/e' [n=430]) were determined in 737 randomly recruited participants of a community-based study (43% obese).

RESULTS

Independent of LVMI and confounders, indexes of adiposity and the homeostasis model of insulin resistance (HOMA-IR) were independently associated with LV diastolic function (p<0.05). In addition, RWT was independently associated with LV diastolic function (p<0.002). Importantly, an independent interaction between HOMA-IR and RWT, but not between blood pressure or age and RWT, was related to LV diastolic function (p<0.05). This translated into an independent relationship between HOMA-IR and lateral e' (partial r=-0.17, p<0.02), septal e' (partial r=-0.14, p=0.05), E/A (partial r=-0.17, p<0.005) and E/e' (partial r=0.19, p<0.01) in those with RWT above, but a lack of relationship between HOMA-IR and LV diastolic function (p>0.59) in those with RWT below the median for the sample. Similarly, HOMA-IR was independently associated with LV diastolic dysfunction in those with RWT above (p<0.05) but not below (p>0.19) the median for the sample.

CONCLUSIONS

The relationship between insulin resistance, but not alternative risk factors and LV diastolic function is markedly modified by the presence of a more concentrically remodeled LV.

Effects of Metformin and Exercise Training, Alone or in Combination, on Cardiac Function in Individuals with Insulin Resistance

Introduction

In patients affected by insulin resistance (IR), metformin (MET) therapy has been shown to exert its positive effects by improving glucose tolerance and preventing the evolution to diabetes. Recently, it was shown that the addition of metformin to physical training did not improve sensitivity to insulin or peak oxygen consumption (peak VO2). The purpose of this study was to establish the effect of metformin and exercise, separately or in combination, on systolic left ventricular (LV) function in individuals with IR.

Methods

Seventy-five patients with IR were enrolled and subsequently assigned to MET, combination MET and exercise, or exercise alone. The LV systolic and diastolic functions were evaluated with standard echocardiography tissue Doppler imaging (TDI) and speckle tracking echocardiography at baseline and after 12 weeks of treatment.

Results

MET, administered alone or in association with exercise, improved longitudinal LV function, as evidenced by an increase in systolic (S) wave on TDI, alongside increases in longitudinal global strain and strain rate in comparison to the group undergoing physical training alone. The traditional echocardiographic parameters showed no statistically significant differences among the three groups before or after the different cycles of therapy.

Conclusions

Treatment with MET, either with or without exercise, but not exercise alone, produced a significant increase in global longitudinal LV systolic function at rest. These findings validate the observation that the use of MET alone or in association with exercise has a crucial role to counteract the negative effects of IR on cardiovascular function.

Electronic supplementary material

The online version of this article (doi:10.1007/s40119-016-0057-3) contains supplementary material, which is available to authorized users.

Preclinical Systolic and Diastolic Dysfunctions in Metabolically Healthy and Unhealthy Obese Individuals

BACKGROUND

Despite the substantial overlap of obesity and metabolic disease, there is heterogeneity with respect to cardiovascular risk. We sought to investigate preclinical differences in systolic and diastolic function in obesity, and specifically compare obese individuals with and without metabolic syndrome (MS).

METHODS AND RESULTS

Obese individuals without cardiac disease with (OB/MS+, n=124) and without (OB/MS-, n=37) MS were compared with nonobese controls (n=29). Diastolic function was assessed by transmitral and tissue Doppler. Global longitudinal strain (LS) and time-based dyssynchrony were assessed by speckle tracking. Both OB/MS- and OB/MS+ groups had similar ejection fraction but worse systolic mechanics as assessed by LS and dyssynchrony when compared with nonobese controls. Specifically, OB/MS- had 2.5% lower LS (SE, 0.7%; P=0.001 in multivariable-adjusted analyses) and 10.8 ms greater dyssynchrony (SE, 3.3 ms; P=0.002), and OB/MS+ had 1.0% lower LS (SE, 0.3%; P<0.001) and 7.8 ms greater dyssynchrony (SE, 1.5 ms; P<0.001) when compared with controls. Obesity was associated with impaired diastolic function regardless of MS status, as evidenced by greater left atrial diameter and left ventricular mass although diastolic dysfunction was more pronounced in OB/MS+ than in OB/MS- individuals.

CONCLUSIONS

Obesity is associated with subclinical differences in both systolic and diastolic function regardless of the presence or absence of MS although MS seems to be associated with worse diastolic dysfunction. When compared with controls, metabolically healthy obese had lower LS, greater dyssynchrony, and early diastolic dysfunction, supporting the notion that obesity per se may have adverse cardiovascular effects regardless of metabolic disease.

Fatty acid metabolism in pulmonary arterial hypertension: role in right ventricular dysfunction and hypertrophy

Pulmonary arterial hypertension (PAH) is a complex, multifactorial disease in which an increase in pulmonary vascular resistance leads to increased afterload on the right ventricle (RV), causing right heart failure and death. Our understanding of the pathophysiology of RV dysfunction in PAH is limited but is constantly improving. Increasing evidence suggests that in PAH RV dysfunction is associated with various components of metabolic syndrome, such as insulin resistance, hyperglycemia, and dyslipidemia. The relationship between RV dysfunction and fatty acid/glucose metabolites is multifaceted, and in PAH it is characterized by a shift in utilization of energy sources toward increased glucose utilization and reduced fatty acid consumption. RV dysfunction may be caused by maladaptive fatty acid metabolism resulting from an increase in fatty acid uptake by fatty acid transporter molecule CD36 and an imbalance between glucose and fatty acid oxidation in mitochondria. This leads to lipid accumulation in the form of triglycerides, diacylglycerol, and ceramides in the cytoplasm, hallmarks of lipotoxicity. Current interventions in animal models focus on improving RV dysfunction through altering fatty acid oxidation rates and limiting lipid accumulation, but more specific and effective therapies may be available in the coming years based on current research. In conclusion, a deeper understanding of the complex mechanisms of the metabolic remodeling of the RV will aid in the development of targeted treatments for RV failure in PAH.

A 12-week randomized double-blind parallel pilot trial of Sinetrol XPur on body weight, abdominal fat, waist circumference, and muscle metabolism in overweight men

Overweight and obesity are associated to increased risk of developing non-communicable diseases that might dramatically affect life expectancy according World Health Organization. Overweight, obesity, and decline in physical activity are correlated to a significant propensity to lose skeletal muscle mass as a result of prolonged inflammation and oxidative stress whereas cohort surveys and clinical investigations have demonstrated health benefits of Citrus-based polyphenols to reverse such regression. Overweight men were included in a double-blind, randomized, parallel pilot trial where they received daily for a 12-week period 900 mg of a Citrus-based polyphenol extract, Sinetrol® XPur. Body composition, anthropometric, and blood parameters were assessed before and at the end of the intervention period. After 12 weeks, while the silhouette slimmed down, metabolic parameters were significantly improved and skeletal muscle catabolism held back. These data suggest that over a 12-week period, the efficacy of the supplement improve both overweight process and correlated skeletal muscle mass metabolism.

Impact of diabetes in patients with pulmonary hypertension

Diabetes complicates management in a number of disease states and adversely impacts survival; how diabetes affects patients with pulmonary hypertension (PH) has not been well characterized. With insulin resistance having recently been demonstrated in PH, we sought to examine the impact of diabetes in these patients. Demographic characteristics, echo data, and invasive hemodynamic data were prospectively collected for 261 patients with PH referred for initial hemodynamic assessment. Diabetes was defined as documented insulin resistance or treatment with antidiabetic medications. Fifty-five patients (21%) had diabetes, and compared with nondiabetic patients, they were older (mean years ± SD, 61 ± 13 vs. 56 ± 16; [Formula: see text]), more likely to be black (29% vs. 14%; [Formula: see text]) and hypertensive (71% vs. 30%; [Formula: see text]), and had higher mean (±SD) serum creatinine levels (1.1 ± 0.5 vs. 1.0 ± 0.4; [Formula: see text]). Diabetic patients had similar World Health Organization functional class at presentation but were more likely to have pulmonary venous etiology of PH (24% vs. 10%; [Formula: see text]). Echo findings, including biventricular function, tricuspid regurgitation, and pressure estimates were similar. Invasive pulmonary pressures and cardiac output were similar, but right atrial pressure was appreciably higher (14 ± 8 mmHg vs. 10 ± 5 mmHg; [Formula: see text]). Despite similar management, survival was markedly worse and remained so after statistical adjustment. In summary, diabetic patients referred for assessment of PH were more likely to have pulmonary venous disease than nondiabetic patients with PH, with hemodynamics suggesting greater right-sided diastolic dysfunction. The markedly worse survival in these patients merits further study.

Gender differences in predictors of left ventricular myocardial relaxation in non-obese, healthy individuals

Background

Previous studies indicate that individuals with metabolic syndrome (MetS) might be at risk for left ventricular (LV) diastolic dysfunction. However, little is known about which metabolic factors contribute to the development of LV dysfunction in individuals who are not obese or overweight and who do not have diabetes mellitus and/or cardiovascular disease.

Methods

Participants without diabetes mellitus, systolic dysfunction, or other heart diseases underwent a thorough physical examination, including tissue Doppler echocardiography. A peak early mitral annular velocity (e′) of <5.0 was designated as indicating abnormal LV myocardial relaxation (LVMR). We performed single and multiple logistic regression analyses of e′ and cardiovascular risk factors, including MetS factors and indicators of major organ dysfunction. Normal-weight subjects (body mass index <25 kg/m²) were also analyzed.

Results

A total of 1055 individuals (mean age, 63 ± 13 years) participated, of which 307 (29.1%) had MetS and 199 (18.9%) had abnormal LVMR. Multiple logistic regression analysis revealed waist circumference (WC) (odds ratio [OR] 1.04, P < 0.05) and age (OR 1.10, P < 0.05) to be predictors of abnormal LVMR. In normal-weight subjects (n = 806), aging (OR 1.08, P < 0.01), abnormal WC (OR 3.80, P < 0.01), and renal dysfunction (OR 2.14, P < 0.01) were predictors of abnormal LVMR. Among MetS factors, abnormal WC in men (OR 3.70, P < 0.01) and high diastolic blood pressure (DBP) in women (OR 4.00, P = 0.01) were related to abnormal LVMR.

Impaired right ventricular hemodynamics indicate preclinical pulmonary hypertension in patients with metabolic syndrome

Background

Metabolic disease can lead to intrinsic pulmonary hypertension in experimental models. The contributions of metabolic syndrome (MetS) and obesity to pulmonary hypertension and right ventricular dysfunction in humans remain unclear. We investigated the association of MetS and obesity with right ventricular structure and function in patients without cardiovascular disease.

Methods and Results

A total of 156 patients with MetS (mean age 44 years, 71% women, mean body mass index 40 kg/m²), 45 similarly obese persons without MetS, and 45 nonobese controls underwent echocardiography, including pulsed wave Doppler measurement of pulmonary artery acceleration time (PAAT) and ejection time. Pulmonary artery systolic pressure was estimated from PAAT using validated equations. MetS was associated with lower tricuspid valve e′ (right ventricular diastolic function parameter), shorter PAAT, shorter ejection time, and larger pulmonary artery diameter compared with controls (P<0.05 for all). Estimated pulmonary artery systolic pressure based on PAAT was 42±12 mm Hg in participants with MetS compared with 32±9 and 32±10 mm Hg in obese and nonobese controls (P for ANOVA <0.0001). After adjustment for age, sex, hypertension, diabetes, body mass index, and triglycerides, MetS remained associated with a 20‐ms–shorter PAAT (β=−20.4, SE=6.5, P=0.002 versus obese). This association persisted after accounting for left ventricular structure and function and after exclusion of participants with obstructive sleep apnea.

Conclusions

MetS is associated with abnormal right ventricular and pulmonary artery hemodynamics, as shown by shorter PAAT and subclinical right ventricular diastolic dysfunction. Estimated pulmonary artery systolic pressures are higher in MetS and preclinical metabolic heart disease and raise the possibility that pulmonary hypertension contributes to the pathophysiology of metabolic heart disease.

Diastolic dysfunction in the diabetic continuum: association with insulin resistance, metabolic syndrome and type 2 diabetes

Background

Diabetes increases the risk of heart failure but the underlying mechanisms leading to diabetic cardiomyopathy are poorly understood. Left ventricle diastolic dysfunction (LVDD) is one of the earliest cardiac changes in these patients. We aimed to evaluate the association between LVDD with insulin resistance, metabolic syndrome (MS) and diabetes, across the diabetic continuum.

Methods

Within a population-based study (EPIPorto), a total of 1063 individuals aged ≥45 years (38% male, 61.2 ± 9.6 years) were evaluated. Diastolic function was assessed by echocardiography, using tissue Doppler analysis (E’ velocity and E/E’ ratio) according to the latest consensus guidelines. Insulin resistance was assessed using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) score.

Results

The HOMA-IR score correlated to E’ velocity (ρ = −0.20;p < 0.0001) and E/E’ ratio (ρ = 0.20; p < 0.0001). There was a progressive worsening in E’ velocity (p for trend < 0.001) and in E/E’ ratio across HOMA-IR quartiles (p for trend <0.001). Individuals in the highest HOMA-IR quartile were more likely to have LVDD, even after adjustment for age, sex, blood pressure and body mass index (adjusted OR: 1.82; 95% CI: 1.09-3.03). From individuals with no MS, to patients with MS and no diabetes, to patients with diabetes, there was a progressive decrease in E’ velocity (11.2 ± 3.3 vs 9.7 ± 3.1 vs 9.2 ± 2.8 cm/s; p < 0.0001), higher E/E’ (6.9 ± 2.3 vs 7.8 ± 2.7 vs 9.0 ± 3.6; p < 0.0001) and more diastolic dysfunction (adjusted OR: 1.62; 95% CI: 1.12-2.36 and 1.78; 95% CI: 1.09-2.91, respectively).

Conclusions

HOMA-IR score and metabolic syndrome were independently associated with LVDD. Changes in diastolic function are already present before the onset of diabetes, being mainly associated with the state of insulin resistance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-014-0168-x) contains supplementary material, which is available to authorized users.

Metabolic syndrome is associated with atrial electrical and mechanical dysfunction

OBJECTIVE

In this study, we aimed to investigate the left atrial (LA) electrical and mechanical functions in patients with metabolic syndrome (MetS).

SUBJECTS AND METHODS

The study population consisted of 87 patients with MetS and 67 controls. Intra-atrial and interatrial electromechanical delays (EDs) were measured with tissue Doppler imaging. P-wave dispersion (Pd) was calculated from the 12-lead electrocardiograms. LA volumes were measured echocardiographically by the biplane area-length method.

RESULTS

Intra-atrial and interatrial EDs and Pd were significantly higher in patients with MetS (10.3 ± 6.3, 21.0 ± 11.5 and 41.7 ± 10.8) than in controls (7.4 ± 5.5, 12.3 ± 10.4 and 29.2 ± 7.4; p = 0.003, p < 0.001 and p < 0.001, respectively). The LA preatrial contraction volume and active emptying volumes were higher in this population, but the LA passive emptying fraction was lower. In the multivariate linear regression analysis, the presence of MetS, LA active emptying volume and left ventricular early diastolic (E) wave velocity/late diastolic (A) wave velocity (E/A) ratios were independent correlates of interatrial ED (p = 0.002, p = 0.001 and p = 0.025, respectively).

CONCLUSIONS

This study showed that intra-atrial and interatrial EDs and Pd were prolonged and LA mechanical functions were impaired in patients with MetS.

Quantification of diastolic dysfunction via the age dependence of diastolic function - impact of insulin resistance with and without type 2 diabetes

BACKGROUND

The alarming prevalence of heart failure with preserved ejection fraction requires quantification of diastolic dysfunction (DDF). Myocardial diastolic velocity E' implies that age is the most important determinant. We tested the hypothesis that age allows for quantification of DDF and assessment of the structural and metabolic determinants in patients with and without type 2 diabetes (D).

METHODS

This prospective, cross-sectional study assessed cardiovascular, metabolic and ultrasound data in 409 consecutive patients (Diabetes Center, Bogenhausen-Munich) between 20 and 90 years without known cardiac disease and either with (n=204) or without D but with common prevalence of cardiovascular risk factors, including a subgroup of healthy individuals (H, n=94).

RESULTS

In H, E' related to age as: E'norm=-0.163∗years+19.69 (R(2)=0.77, p<0.0001). According to this 1% reduction by annual physiologic aging, DDF was quantitated as E'-E' norm. Compared to nondiabetics, D patients were older, had greater BMI, lower E', more cardiovascular risk and greater DDF. In nondiabetics, grading of DDF by E-E'norm correlated with grading by filling pressure E/E'. Determinants of DDF by multivariate analysis included pulse wave velocity, diastolic blood pressure and the triglyceride/HDL ratio (a marker of insulin resistance) in nondiabetics and in D the same risk factors in reverse sequence and heart rate. Neither left atrial size nor left ventricular mass had significant impact.

CONCLUSIONS

The physiological impact of age on myocardial function consists of a 1% annual reduction in E' and enables precise quantification of diastolic dysfunction thereby unmasking the importance of metabolic risk for DDF.

Subclinical atherosclerosis and ambulatory blood pressure in children with metabolic syndrome

BACKGROUND

The metabolic syndrome (MS) has reached epidemic proportions worldwide. This syndrome is associated with cardiovascular risk factors, including functional and structural cardiac and vascular changes. The aim of our study was to evaluate subclinical atherosclerosis and its associated risk factors in children with MS.

METHODS

The study cohort comprised 52 children with MS and 38 age- and sex-matched healthy children. The diagnosis of MS was made according to criteria adopted by the World Health Organization. Blood pressure based on 24-h ambulatory blood pressure monitoring (ABPM), carotid intima-media thickness (cIMT), carotid distensibility coefficient (DC) and flow-mediated endothelium-dependent dilation (EDD) were assessed in all children.

RESULTS

We found a significantly higher cIMT in children with MS than in healthy children, but carotid DC and flow-mediated EDD were lower in the former. Multivariate analysis revealed that a higher cIMT was independently associated with a higher nighttime systolic blood pressure (SBP) and lower high-density lipoprotein-cholesterol (β = 0.386, p = 0.011 and β = 0.248, p = 0.042, respectively). Also, higher nighttime SBP remained an independent predictor of lower DC (β = 0.495, p = 0.009), and higher 24-h SBP was the only independent predictor for a lower EDD (β = 0.532, p = 0.004).

CONCLUSIONS

Atherosclerotic vascular changes were common among our pediatric patients with MS and easily determined by high-resolution ultrasound imaging. In particular, subclinical atherosclerosis was clearly associated with nocturnal or 24-h systolic hypertension as measured by ABPM. We therefore recommend that subclinical vascular changes and AMBP measurements should be used as diagnostic markers to predict atherosclerotic risks in this pediatric patient group.