Relationship of impaired glucose tolerance to left ventricular structure and function: The Strong Heart Study

Influence of gestational diabetes mellitus on subclinical myocardial dysfunction during pregnancy: A systematic review and meta-analysis

OBJECTIVE

The correlation between gestational diabetes mellitus (GDM) and subclinical myocardial dysfunction has been poorly investigated. Accordingly, we performed a meta-analysis to examine the influence of GDM on left ventricular (LV) global longitudinal strain (GLS), assessed by speckle tracking echocardiography (STE), during pregnancy.

STUDY DESIGN

All echocardiographic studies assessing conventional echoDoppler parameters and LV-GLS in GDM women vs. healthy controls, selected from PubMed and EMBASE databases, were included. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment of Case-Control Studies. The subtotal and overall standardized mean differences (SMDs) of LV-GLS were calculated using the random-effect model.

RESULTS

The full-texts of 10 studies with 1147 women with GDM and 7706 pregnant women without diabetes were analyzed. GDM women enrolled in the included studies were diagnosed with a small reduction in LV-GLS in comparison to controls (average value -19.4 ± 2.5 vs -21.8 ± 2.5 %, P < 0.001) and to the accepted reference values (more negative than -20 %). Substantial heterogeneity was detected for the included studies, with an overall statistic value I2 of 94.4 % (P < 0.001). Large SMDs were obtained for the included studies, with an overall SMD of -0.97 (95 %CI -1.32, -0.63, P < 0.001). Egger's test for a regression intercept gave a P-value of 0.99, indicating no publication bias. On meta-regression analysis, all moderators and/or potential confounders (age at pregnancy, BMI, systolic blood pressure and ethnicity) were not significantly associated with effect modification (all P < 0.05).

CONCLUSIONS

GDM is independently associated with subclinical myocardial dysfunction in pregnancy. STE analysis allows to identify, among GDM women, those who might benefit of targeted non-pharmacological and/or pharmacological interventions, aimed at reducing the risk of developing type 2 diabetes and cardiovascular complications later in life.

The interplay of inflammation, exosomes and Ca2+ dynamics in diabetic cardiomyopathy

Diabetes mellitus is one of the prime risk factors for cardiovascular complications and is linked with high morbidity and mortality. Diabetic cardiomyopathy (DCM) often manifests as reduced cardiac contractility, myocardial fibrosis, diastolic dysfunction, and chronic heart failure. Inflammation, changes in calcium (Ca²⁺) handling and cardiomyocyte loss are often implicated in the development and progression of DCM. Although the existence of DCM was established nearly four decades ago, the exact mechanisms underlying this disease pathophysiology is constantly evolving. Furthermore, the complex pathophysiology of DCM is linked with exosomes, which has recently shown to facilitate intercellular (cell-to-cell) communication through biomolecules such as micro RNA (miRNA), proteins, enzymes, cell surface receptors, growth factors, cytokines, and lipids. Inflammatory response and Ca²⁺ signaling are interrelated and DCM  has been known to adversely affect many of these signaling molecules either qualitatively and/or quantitatively. In this literature review, we have demonstrated that Ca²⁺ regulators are tightly controlled at different molecular and cellular levels during various biological processes in the heart. Inflammatory mediators, miRNA and exosomes are shown to interact with these regulators, however how these mediators are linked to Ca²⁺ handling during DCM pathogenesis remains elusive. Thus, further investigations are needed to understand the mechanisms to restore cardiac Ca²⁺ homeostasis and function, and to serve as potential therapeutic targets in the treatment of DCM.

Effects of Exercise On Coronary Flow Reserve And Biochemical Parameters in Patients With Type 2 Diabetes Mellitus

The most important mortality and morbidity causes in diabetic patients are coronary, peripheral and cerebral diseases. The aim of our study was to noninvasively determine dysfunction in epicardial coronary arteries and microvascular circulation with measurement of coronary flow reserve using transthoracic echocardiography in patients with type 2 diabetes despite absence of ischemic symptoms, and to demonstrate the amelioration in endothelial functions, glycemic control and insulin resistance along with increase in coronary flow reserve after 8 weeks of regular exercise. 40 patients diagnosed with type 2 diabetes in Istanbul Facuty of Medicine, Department of Diabetes, who were on follow-up for at least three years due to diabetes, without ischemic symptoms and 20 healthy subjects took part in study. Basal values before exercise of diabetic patients who were included in the exercise program were compared with basal values of diabetic patients who did not exercise regularly. To summarize, regular exercise and physical activity are highly important in diabetic patients for primary and secondary protection against cardiovascular incidents. Physical activity increases insulin sensitivity in diabetic patients, and has many positive effects on glucose metabolism. It is the important way to decrease obesity and visceral fat tissue. There is evidence pointing out that regular exercise can defer or even prevent initiation of diabetes.

Two-dimensional speckle tracking echocardiography in assessing the subclinical myocardial dysfunction in patients with gestational diabetes mellitus

Background

Gestational diabetes mellitus (GDM) may increase the risk of cardiovascular disease and accompany asymptomatic deterioration of the myocardial function. This study aims to identify the subclinical impact of GDM on maternal left ventricular function by two-dimensional speckle tracking echocardiography (2D-STE).

Methods

We prospectively recruited 47 women with GDM and 62 healthy pregnant women who underwent transthoracic echocardiography (TTE) at 24 to 28 weeks of pregnancy. GDM diagnosis agreed with the IADPSG criteria. TTE was performed according to the criteria of the American Society of Echocardiography. Conventional echocardiographic data and 2D-STE parameters were compared between the two groups.

Results

Age, gestational weeks, heart rate, and conventional echocardiographic parameters had no difference between the two groups. The average LV global longitudinal strain (LV-GLS) of GDM patients was lower than controls (18.14 ± 2.53 vs. 22.36 ± 6.33, p < 0.001), and 31 patients (66%) in our study had an absolute LV-GLS less than 20%. The LA reservoir and conduit strain in patients with GDM were also significantly reduced (32.71 ± 6.64 vs. 38.00 ± 7.06, 20.41 ± 5.69 vs. 25.56 ± 5.73, p < 0.001). However, there was no significant difference in LA contractile function between the two groups. In multiple regression analysis, LV-GLS and LA conduit strain independently associated with GDM.

Conclusions

2D-STE could detect the subclinical myocardial dysfunction more sensitively than conventional echocardiography, with LV-GLS and LA conduit strain as independent indicators of the GDM impact on maternal cardiac function during pregnancy.

Disturbed Glucose Metabolism and Left Ventricular Geometry in the General Population

Background: This study sought to investigate the prevalence and clinical outcome of left ventricular (LV) geometry in prediabetes and type 2 diabetes mellitus (T2DM) and the impact of glucose metabolism on the incidence of left ventricular hypertrophy (LVH). Methods: 15,010 subjects (35–74 years) of the population-based Gutenberg Health Study were categorized into euglycemia, prediabetes, and T2DM according to clinical and metabolic (HbA1c) information. Clinical outcome was assessed via structured follow-up. Results: The study comprised 12,121 individuals with euglycemia (81.6%), 1415 with prediabetes (9.5%), and 1316 with T2DM (8.9%). Prevalence of LVH increased from euglycemia (10.2%) over prediabetes (17.8%) to T2DM (23.8%). Prediabetes and T2DM were associated with increased LV mass index (prediabetes: β1.3 (95% CI 0.78–1.81), p < 0.0001; T2DM: β2.37 (95% CI 1.81; 2.92), p < 0.0001) independent of age, sex, and cardiovascular risk factors (CVRF). The frequency of LVH was related to the presence of T2DM (prevalence ratio (PR)T2DM 1.2 (95% CI 1.06–1.35), p = 0.0038). T2DM was related to mortality independent of age, sex, and CVRF regardless of LVH (hazard ratio (HR)T2DM-LVH 2.67 (95% CI 1.94–3.66), p < 0.0001; HRT2DM-noLVH 1.59 (95% CI 1.29–1.96), p < 0.0001), prediabetes was only associated with outcome in individuals with LVH independent of age and sex (HRprediabetes-LVH 1.51 (95% CI 1.01–2.25), p = 0.045). Neither T2DM nor prediabetes were predictors of incident LVH after adjustment for clinical covariates. Conclusions: Prediabetes and T2DM promote alterations of cardiac geometry. T2DM and particularly the coprevalence of T2DM with LVH substantially reduce life expectancy. These findings highlight the need for new therapeutic and screening approaches to prevent and detect cardiometabolic diseases at an early stage.

Three-dimensional echocardiography and cardiac strain imaging in women with gestational diabetes mellitus

OBJECTIVES

Gestational diabetes mellitus (GDM) is associated with premature cardiovascular disease and adverse cardiovascular outcome in the mother. Subclinical cardiac functional changes in the left ventricle have been reported during pregnancy in women with GDM using conventional echocardiography, but results are inconsistent. The aims of the current study were to assess whether GDM is associated with biventricular systolic dysfunction in the mother and whether these cardiac changes can be detected using the novel echocardiographic modalities of strain imaging and three-dimensional (3D) echocardiography.

METHODS

This was a cross-sectional study in women with GDM and controls examined at 26-40 weeks of gestation. All women underwent echocardiography, and 3D volumes of the left and right ventricles and left atrium were collected. Ejection fraction and left ventricular mass were measured using 3D echocardiography. Left ventricular mass was indexed to body surface area. Speckle-tracking echocardiography was used to assess global longitudinal strain of the left and right ventricles and strain of the left atrium.

RESULTS

The study population included 123 women with GDM and 246 controls. Women with GDM, compared to controls, were older (35.1 ± 5.2 vs 32.4 ± 5.5 years; P < 0.001), had higher body mass index (30.6 (interquartile range (IQR), 26.2-35.2) vs 27.5 (IQR, 24.7-30.7) kg/m² ; P < 0.001) and had higher systolic blood pressure (119.9 ± 11.2 vs 116.4 ± 12.0 mmHg; P = 0.007). In all women with GDM, there was good glycemic control. In women with GDM, compared to controls, there was lower global longitudinal strain of the left ventricle (-19.3% (IQR, -21.4 to -17.6%) vs -20.1% (IQR, -22.1 to -18.7%); P = 0.002) and right ventricle (-22.2% (IQR, -26.1 to -19.8%) vs -24.1% (IQR, -27.0 to -21.9%); P < 0.001). There was no significant difference between the groups in ejection fraction, left ventricular mass, diastolic function assessed by left atrial strain, or 3D functional indices.

CONCLUSIONS

Women with GDM, compared to women with uncomplicated pregnancy, have lower left and right ventricular myocardial deformation. Volumetric assessment using 3D echocardiography does not provide additional information about maternal cardiac function. Strain imaging is a sensitive echocardiographic modality to detect early cardiac functional changes in women with GDM. Further studies are needed to assess the pattern of deterioration of cardiac function with advancing age in women with a history of GDM. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Specific amino acid supplementation rescues the heart from lipid overload-induced insulin resistance and contractile dysfunction by targeting the endosomal mTOR-v-ATPase axis

Objective

The diabetic heart is characterized by extensive lipid accumulation which often leads to cardiac contractile dysfunction. The underlying mechanism involves a pivotal role for vacuolar-type H⁺-ATPase (v-ATPase, functioning as endosomal/lysosomal proton pump). Specifically, lipid oversupply to the heart causes disassembly of v-ATPase and endosomal deacidification. Endosomes are storage compartments for lipid transporter CD36. However, upon endosomal deacidification, CD36 is expelled to translocate to the sarcolemma, thereby inducing myocardial lipid accumulation, insulin resistance, and contractile dysfunction. Hence, the v-ATPase assembly may be a suitable target for ameliorating diabetic cardiomyopathy. Another function of v-ATPase involves the binding of anabolic master-regulator mTORC1 to endosomes, a prerequisite for the activation of mTORC1 by amino acids (AAs). We examined whether the relationship between v-ATPase and mTORC1 also operates reciprocally; specifically, whether AA induces v-ATPase reassembly in a mTORC1-dependent manner to prevent excess lipids from entering and damaging the heart.

Methods

Lipid overexposed rodent/human cardiomyocytes and high-fat diet-fed rats were treated with a specific cocktail of AAs (lysine/leucine/arginine). Then, v-ATPase assembly status/activity, cell surface CD36 content, myocellular lipid uptake/accumulation, insulin sensitivity, and contractile function were measured. To elucidate underlying mechanisms, specific gene knockdown was employed, followed by subcellular fractionation, and coimmunoprecipitation.

Results

In lipid-overexposed cardiomyocytes, lysine/leucine/arginine reinternalized CD36 to the endosomes, prevented/reversed lipid accumulation, preserved/restored insulin sensitivity, and contractile function. These beneficial AA actions required the mTORC1–v-ATPase axis, adaptor protein Ragulator, and endosomal/lysosomal AA transporter SLC38A9, indicating an endosome-centric inside-out AA sensing mechanism. In high-fat diet-fed rats, lysine/leucine/arginine had similar beneficial actions at the myocellular level as in vitro in lipid-overexposed cardiomyocytes and partially reversed cardiac hypertrophy.

Conclusion

Specific AAs acting through v-ATPase reassembly reduce cardiac lipid uptake raising the possibility for treatment in situations of lipid overload and associated insulin resistance.

• High physiological concentrations of specific AAs (K/L/R) activate v-ATPase.

• The KLR mix activates v-ATPase by mutually dependent activation of mTORC1.

• KLR-induced v-ATPase activation enables endosomes to retain lipid transporter CD36.

• KLR mends lipid-induced insulin resistance and cardiomyocytic contractile dysfunction.

• KLR reverses v-ATPase disassembly and cardiac hypertrophy in high-fat diet-fed rats.

The TRIB3 R84 variant is associated with increased left ventricular mass in a sample of 2426 White individuals

BACKGROUND

Prior studies in animal models showed that increased cardiac expression of TRIB3 has a pathogenic role in inducing left ventricular mass (LVM). Whether alterations in TRIB3 expression or function have a pathogenic role in inducing LVM increase also in humans is still unsettled. In order to address this issue, we took advantage of a nonsynonymous TRIB3 Q84R polymorphism (rs2295490), a gain-of-function amino acid substitution impairing insulin signalling, and action in primary human endothelial cells which has been associated with insulin resistance, and early vascular atherosclerosis.

METHODS

SNP rs2295490 was genotyped in 2426 White adults in whom LVM index (LVMI) was assessed by validated echocardiography-derived measures.

RESULTS

After adjusting for age and sex, LVMI progressively and significantly increased from 108 to 113, to 125 g/m2 in Q84Q, Q84R, and R84R individuals, respectively (Q84R vs. Q84Q, P = 0.03; R84R vs. Q84Q, P < 0.0001). The association between LVMI and the Q84R and R84R genotype remained significant after adjusting for blood pressure, smoking habit, fasting glucose levels, glucose tolerance status, anti-hypertensive treatments, and lipid-lowering therapy (Q84R vs. Q84Q, P = 0.01; R84R vs. Q84Q, P < 0.0001).

CONCLUSIONS

We found that the gain-of-function TRIB3 Q84R variant is significantly associated with left ventricular mass in a large sample of White nondiabetic individual of European ancestry.

Sex-specific differences in left ventricular mass and myocardial energetic efficiency in non-diabetic, pre-diabetic and newly diagnosed type 2 diabetic subjects

Background

Women with type 2 diabetes (T2DM) have a higher excess risk for cardiovascular disease (CVD) than their male counterparts. However, whether the risk for CVD is higher in prediabetic women than men is still debated. We aimed to determine whether sex-related differences exist in left ventricular mass index (LVMI), and myocardial mechano-energetic efficiency (MEEi) in with normal glucose tolerant (NGT), pre-diabetic and newly diagnosed type 2 diabetic subjects.

Methods

Sex-related differences in LVMI and myocardial MEEi, assessed by validated echocardiography-derived measures, were examined among 1562 adults with NGT, prediabetes, and newly diagnosed T2DM, defined according to fasting glucose, 2-h post-load glucose, or HbA1c.

Results

Worsening of glucose tolerance in both men and women was associated with an increase in age-adjusted LVMI and myocardial MEEi. Women with newly diagnosed T2DM exhibited greater relative differences in LVMI and myocardial MEEi than diabetic men when compared with their NGT counterparts. Prediabetic women exhibited greater relative differences in myocardial MEEi, but not in LVMI, than prediabetic men when compared with their NGT counterparts. The statistical test for interaction between sex and glucose tolerance on both LVMI (P < 0.0001), and myocardial MEEi (P < 0.0001) was significant suggesting a sex-specific association.

Conclusions

Left ventricle is subject to maladaptive changes with worsening of glucose tolerance, especially in women with newly diagnosed T2DM. The sex-specific increase in LVM and decrease in MEEi, both being predictors of CVD, may have a role in explaining the stronger impact of T2DM on the excess risk of CVD in women than in men.

Association between insulin resistance and left ventricular hypertrophy in asymptomatic, Black, sub-Saharan African, hypertensive patients: a case-control study

Background

Conflicting information exists regarding the association between insulin resistance (IR) and left ventricular hypertrophy (LVH). We described the associations between obesity, fasting insulinemia, homeostasis model assessment of insulin resistance (HOMA-IR), and LVH in Black patients with essential hypertension.

Methods

A case–control study was conducted at the Centre Médical de Kinshasa (CMK), the Democratic Republic of the Congo, between January and December 2019. Cases and controls were hypertensive patients with and without LVH, respectively. The relationships between obesity indices, physical inactivity, glucose metabolism and lipid disorder parameters, and LVH were assessed using linear and logistic regression analyses in simple and univariate exploratory analyses, respectively. When differences were observed between LVH and independent variables, the effects of potential confounders were studied through the use of multiple linear regression and in conditional logistic regression in multivariate analyses. The coefficients of determination (R²), adjusted odds ratios (aORs), and their 95% confidence intervals (95% CIs) were calculated to determine associations between LVH and the independent variables.

Results

Eighty-eight LVH cases (52 men) were compared against 132 controls (81 men). Variation in left ventricular mass (LVM) could be predicted by the following variables: age (19%), duration of hypertension (31.3%), body mass index (BMI, 44.4%), waist circumference (WC, 42.5%), glycemia (20%), insulinemia (44.8%), and HOMA-IR (43.7%). Hypertension duration, BMI, insulinemia, and HOMA-IR explained 68.3% of LVM variability in the multiple linear regression analysis. In the logistic regression model, obesity increased the risk of LVH by threefold [aOR 2.8; 95% CI (1.06–7.4); p = 0.038], and IR increased the risk of LVH by eightfold [aOR 8.4; 95 (3.7–15.7); p < 0.001].

Conclusion

Obesity and IR appear to be the primary predictors of LVH in Black sub-Saharan African hypertensive patients. The comprehensive management of cardiovascular risk factors should be emphasized, with particular attention paid to obesity and IR. A prospective population-based study of Black sub-Saharan individuals that includes the use of serial imaging remains essential to better understand subclinical LV deterioration over time and to confirm the role played by IR in Black sub-Saharan individuals with hypertension.

The role of insulin resistance in the relation of visceral, abdominal subcutaneous and total body fat to cardiovascular function

BACKGROUND AND AIMS

The separate cardiovascular effects of type 2 diabetes and adiposity remain to be examined. This study aimed to investigate the role of insulin resistance in the relations of visceral (VAT), abdominal subcutaneous (aSAT) adipose tissue and total body fat (TBF) to cardiovascular remodeling.

METHODS AND RESULTS

In this cross-sectional analysis of the population-based Netherlands Epidemiology of Obesity study, 914 middle-aged individuals (46% men) were included. Participants underwent magnetic resonance imaging. Standardized linear regression coefficients (95%CI) were calculated, adjusted for potential confounding factors. All fat depots and insulin resistance (HOMA-IR), separate from VAT and TBF, were associated with lower mitral early and late peak filling rate ratios (E/A): -0.04 (-0.09;0.01) per SD (54 cm²) VAT; -0.05 (-0.10;0.00) per SD (94 cm²) aSAT; -0.09 (-0.16;-0.02) per SD (8%) TBF; -0.11 (-0.17;-0.05) per 10-fold increase in HOMA-IR, whereas VAT and TBF were differently associated with left ventricular (LV) end-diastolic volume: -8.9 (-11.7;-6.1) mL per SD VAT; +5.4 (1.1;9.7) mL per SD TBF. After adding HOMA-IR to the model to evaluate the mediating role of insulin resistance, change in E/A was -0.02 (-0.07;0.04) per SD VAT; -0.03 (-0.08;0.02) per SD aSAT; -0.06 (-0.13;0.01) per SD TBF, and change in LV end-diastolic volume was -7.0 (-9.7;-4.3) mL per SD VAT. In women, adiposity but not HOMA-IR was related to higher aortic arch pulse wave velocity.

CONCLUSION

Insulin resistance was associated with reduced diastolic function, separately from VAT and TBF, and partly mediated the associations between adiposity depots and lower diastolic function.

Paired maternal and fetal cardiac functional measurements in women with gestational diabetes mellitus at 35-36 weeks' gestation

BACKGROUND

Gestational diabetes mellitus is associated with early-onset cardiovascular disease and increased incidence of adverse cardiovascular outcomes in mothers and their offspring. Few studies with a limited number of patients have reported subclinical cardiac changes in association with gestational diabetes mellitus; however, it remains unclear whether the mother and the fetus respond in a similar fashion to gestational diabetes mellitus; thus, by assessing the heart of one, we can estimate or predict changes in the other.

OBJECTIVE

This study aimed to compare maternal and fetal cardiovascular functions in the third trimester between women with gestational diabetes mellitus and women with uncomplicated pregnancy and to explore whether gestational diabetes mellitus affects to the same extent the maternal and fetal heart.

STUDY DESIGN

This was a cross-sectional study of maternal and fetal echocardiography for assessment of cardiovascular function in the third trimester in women with singleton pregnancies who received a diagnosis of gestational diabetes mellitus and the control group with uncomplicated pregnancies.

RESULTS

In this study, we included 161 women with gestational diabetes mellitus and 483 women with uncomplicated pregnancies. Compared with women in the control group, women with gestational diabetes mellitus were older (34.5, standard deviation, 5.3 years] vs 32.5, standard deviation, 4.8 years]; P<.001), had higher body mass index (31.3 kg/m² [standard deviation, 5.8] vs 28.6 kg/m² [standard deviation, 4.4]; P<.001), had lower weight gain during pregnancy (8.3 [interquartile range, 4.8-11 kg] vs 10.8 [interquartile range, 8.2-13.5 kg]; P<.001), and delivered babies with lower birthweight (P<.001). After multivariable analysis, accounting for differences in maternal characteristics and fetal weight, mothers with gestational diabetes mellitus had lower left ventricular diastolic and systolic (tissue Doppler systolic [s'] wave) functional indices (P<.01 for both) compared with those of mothers in the control group. The noted cardiac changes did not fulfill the adult criteria for clinical cardiac dysfunction. No differences in hemodynamic indices (cardiac output and peripheral vascular resistance) and left ventricular mass were noted between the groups. Fetuses of mothers with gestational diabetes mellitus had more globular-shaped hearts with increased right and left ventricular sphericity indices (P<.001 for both) and reduced global longitudinal right and left ventricular systolic functional indices (P<.001 for both). The effect of gestational diabetes mellitus on maternal and fetal hearts was different, and there was no clear association between the two.

CONCLUSION

In the third trimester, in pregnancies with gestational diabetes mellitus, there were subclinical cardiac changes in both the mother and the fetus, but there was no significant difference in any of the fetal cardiac parameters between women with and women without unfavorable cardiac profile. This suggests that the stimulus for cardiovascular responses in the mother and fetus may not be the same in pregnancies with gestational diabetes mellitus.

Maternal cardiac function in gestational diabetes mellitus at 35-36 weeks' gestation and 6 months postpartum

OBJECTIVE

Women with gestational diabetes mellitus (GDM) are at increased risk for adverse cardiovascular outcome later in life. However, it is uncertain whether this increased risk is due to cardiovascular changes occurring during pregnancy and persisting thereafter or to an adverse underlying cardiovascular risk factor profile. Some studies have reported that GDM is associated with reduced systolic and diastolic left ventricular function in pregnancy; however, it remains unknown whether these changes persist after delivery. The objective of this study was to compare cardiac function and structure in women with GDM and those with uncomplicated pregnancy at 35-36 weeks' gestation and about 6 months after delivery.

METHODS

This was a longitudinal study in which women with GDM and those with uncomplicated pregnancy had detailed cardiovascular assessment at 35-36 weeks' gestation and repeat examination around 6 months after delivery. In all women, left ventricular systolic and diastolic indices were measured and left ventricular mass indexed for body surface area was calculated. Cardiac output and peripheral vascular resistance were also calculated using echocardiography. Linear mixed model analysis accounting for differences in maternal characteristics was carried out to compare findings of cardiovascular function between the GDM group and controls and within each group at 35-36 weeks' gestation and at 6 months after delivery.

RESULTS

We studied 73 women with GDM and 73 controls with uncomplicated pregnancy. At 35-36 weeks' gestation, women with GDM, compared to controls, had higher E/e' ratio and lower E/A ratio and global longitudinal systolic strain; there were no significant differences between the groups in ejection fraction. Left ventricular mass indexed for body surface area was also increased in women with GDM. There were no significant differences between the groups in cardiac output and peripheral vascular resistance. At 6 months after delivery, cardiac functional indices improved in both patients with GDM and controls, but in the GDM group, compared to controls, there was a lower degree of improvement in E/A ratio and global longitudinal systolic strain.

CONCLUSION

In the third trimester, patients with GDM have subtle differences in diastolic and systolic left ventricular function compared to controls and, despite improvement after delivery, these changes persist for at least 6 months. Long-term follow-up is therefore needed to assess whether women with GDM are at risk for an accelerated decline in their cardiac function and, if so, whether this trend can be reversed or delayed by optimal cardiovascular risk factor modification. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Diabetes Mellitus Is an Independent Predictor for the Development of Heart Failure: A Population Study

OBJECTIVES

To delineate the impact of diabetes mellitus (DM) on the development of cardiovascular diseases in a community population.

PATIENTS & METHODS

Cross-sectional survey of residents randomly selected through the Rochester Epidemiology Project, 45 years or older, of Olmsted County as of June 1, 1997, through September 30, 2000. Responders (2042) underwent assessment of systolic and diastolic function using echocardiography. The current analyses included all participants with DM and were compared with a group of participants without DM matched 1:2 for age, sex, hypertension, and coronary artery disease. Baseline characteristics and laboratory and echocardiography findings between groups were compared along with rates of mortality due to various cardiovascular conditions.

RESULTS

We identified 116 participants with DM and 232 matched participants without DM. Those with DM had a higher body mass index and plasma insulin and serum glucose levels. Although left ventricular ejection fractions were similar, E/e' ratio (9.7 vs 8.5; P=.001) was higher in DM vs non-DM. During a follow-up of 10.8 (interquartile range, 7.8-11.7) years, participants with DM had a higher incidence of heart failure (HF); hazard ratio, 2.1; 95% confidence limits, 1.2-3.6; P=.01) and 10-year Kaplan-Meier rate of 21% (22 of 116) vs 12% (24 of 232) compared with those without DM. We also examined the subgroup of participants without diastolic dysfunction. In this subgroup, those with DM had an increased risk for HF; hazard ratio, 2.5; 95% confidence limits, 1.0-6.3; P=.04).

CONCLUSION

In this cohort, participants with DM have an increased incidence of HF over a 10-year follow-up period even in the absence of underlying diastolic dysfunction. These findings suggest that DM is an independent risk factor for the development of HF and supports the concept of DM cardiomyopathy.

Elevated 1-h post-load plasma glucose is associated with right ventricular morphofunctional parameters in hypertensive patients

PURPOSE

Emerging data demonstrate that type 2 diabetes mellitus (T2DM) is associated with right ventricular (RV) dysfunction. A cutoff point of 155 mg/dL for the 1-hour (h) post-load plasma glucose, during oral glucose tolerance test (OGTT), identifies patients with normal glucose tolerance (NGT) at high risk to develop T2DM and cardiovascular (CV) disease. We investigated if 1-h post-load glucose may affect RV geometry and function in a group of never-treated hypertensive individuals.

METHODS

We enrolled 446 Caucasian newly diagnosed hypertensive outpatients. All patients underwent an OGTT and a standard echocardiography. The tricuspid annular plane systolic excursion (TAPSE) and the RV fractional area change (RVFAC) were measured together with systolic pulmonary arterial pressure (s-PAP) and pulmonary vascular resistances (PVR). Insulin sensitivity was evaluated using the Matsuda index.

RESULTS

Among all partecipants, 296 had NGT, 100 impaired glucose tolerance (IGT), and 50 T2DM. Considering the cutoff point of 155 mg/dl for 1-h glucose, NGT subjects were stratified into two groups: NGT < 155 (n = 207), NGT ≥ 155 (n = 89). Subjects NGT ≥ 155 presented a worse metabolic and inflammatory profile than NGT < 155. RV functional parameters (TAPSE, RVFAC, TAPSE/s-PAP, and TAPSE/PVR) were significantly reduced in NGT ≥ 155 subjects compared with NGT < 155 patients. On the contrary, s-PAP and PVR were significantly higher. At multiple regression analysis, 1-h glucose was the strongest predictor of TAPSE in NGT ≥ 155, IGT, and T2DM.

CONCLUSIONS

The presence of RV impairment in hypertensive NGT ≥ 155 subjects further complicates their CV burden and it may, at least in part, justify the worse clinical outcome in this setting of patients.

Vascular endothelial dysfunction, a major mediator in diabetic cardiomyopathy

Diabetes mellitus is currently a major public health problem. A common complication of diabetes is cardiac dysfunction, which is recognized as a microvascular disease that leads to morbidity and mortality in diabetic patients. While ischemic events are commonly observed in diabetic patients, the risk for developing heart failure is also increased, independent of the severity of coronary artery disease and hypertension. This diabetes-associated clinical entity is considered a distinct disease process referred to as "diabetic cardiomyopathy". However, it is not clear how diabetes promotes cardiac dysfunction. Vascular endothelial dysfunction is thought to be one of the key risk factors. The impact of diabetes on the endothelium involves several alterations, including hyperglycemia, fatty acid oxidation, reduced nitric oxide (NO), oxidative stress, inflammatory activation, and altered barrier function. The current review provides an update on mechanisms that specifically target endothelial dysfunction, which may lead to diabetic cardiomyopathy.

Diabetes mellitus and insulin resistance associate with left ventricular shape and torsion by cardiovascular magnetic resonance imaging in asymptomatic individuals from the multi-ethnic study of atherosclerosis

BACKGROUND

Although diabetes mellitus (DM) and insulin resistance associate with adverse cardiac events, the associations of left ventricular (LV) remodeling and function with compromised glucose metabolism have not been fully evaluated in a general population. We used cardiovascular magnetic resonance (CMR) to evaluate how CMR indices are associated with DM or insulin resistance among participants before developing cardiac events.

METHODS

We studied 1476 participants who were free of clinical cardiovascular disease and who underwent tagged CMR in the Multi-Ethnic Study of Atherosclerosis (MESA). LV shape and longitudinal myocardial shortening and torsion were assessed by CMR. A higher sphericity index represents a more spherical LV shape. Multivariable linear regression was used to evaluate the associations of DM or homeostasis model assessment-estimated insulin resistance (HOMA-IR) with CMR indices.

RESULTS

In multiple linear regression, longitudinal shortening was lower in impaired fasting glucose than normal fasting glucose (NFG) (0.36% lower vs. NFG, p < 0.05); torsion was greater in treated DM (0.24 °/cm greater vs. NFG, p < 0.05) after full adjustments. Among participants without DM, greater log-HOMA-IR was correlated with greater LV mass (3.92 g/index, p < 0.05) and LV mass-to-volume ratio (0.05 /index, p < 0.01), and lower sphericity index (- 1.26/index, p < 0.01). Greater log-HOMA IR was associated with lower longitudinal shortening (- 0.26%/index, p < 0.05) and circumferential shortening (- 0.30%/index, p < 0.05). Torsion was positively correlated with log-HOMA-IR until 1.5 of log-HOMA-IR (0.16 °/cm/index, p = 0.030).), and tended to fall once above 1.5 of log-HOMA-IR (- 0.50 °/cm/index, p = 0.203). The sphericity index was associated negatively with LV mass-to-volume ratio (- 0.02/%, p < 0.001) and torsion (- 0.03°/cm/%, p < 0.001).

CONCLUSIONS

Glucose metabolism disorders are associated with LV concentric remodeling, less spherical shape, and reduced systolic myocardial shortening in the general population. Although torsion is higher in participants who are treated for DM and impaired insulin resistance, myocardial shortening was progressively decreased with higher HOMA-IR and torsion was increased only with less severe insulin resistance.

CLINICAL TRIAL REGISTRATION

Multi-Ethnic Study of Atherosclerosis (MESA): A full list of participating MESA investigators and institutions can be found at http://www.mesa-nhlbi.org/ . Study Start Date: January 1999 ( NCT00005487 ).

Echocardiographic feature of diabetic cardiomyopathy: where are we now?

We are now entering the very exciting era of treatment and management of diabetes mellitus (DM) with the emergence of new therapeutic agents, including sodium-glucose cotransporter 2 inhibitors (SGLT2i) and dipeptidyl peptidase-4 inhibitor (DPP-4i). From a cardiology and echocardiography perspective, the existence of diabetic cardiomyopathy has been proven through over four decades of discussion. DM is highly prevalent in patients with heart failure (HF). Independent associations are found after adjusting for hypertension (HTN) and coronary artery disease (CAD). In patients with both DM and HF, the prognosis is extremely dismal. In this review, the main focus is on both diabetic cardiomyopathy per se and its typical features (including myocardial additive insult related to DM), diagnosis, and management.

Human embryonic stem cell-derived cardiomyocytes as an in vitro model to study cardiac insulin resistance

Patients with type 2 diabetes (T2D) and/or insulin resistance (IR) have an increased risk for the development of heart failure (HF). Evidence indicates that this increased risk is linked to an altered cardiac substrate preference of the insulin resistant heart, which shifts from a balanced utilization of glucose and long-chain fatty acids (FAs) towards an almost complete reliance on FAs as main fuel source. This shift leads to a loss of endosomal proton pump activity and increased cardiac fat accumulation, which eventually triggers cardiac dysfunction. In this review, we describe the advantages and disadvantages of currently used in vitro models to study the underlying mechanism of IR-induced HF and provide insight into a human in vitro model: human embryonic stem cell-derived cardiomyocytes (hESC-CMs). Using functional metabolic assays we demonstrate that, similar to rodent studies, hESC-CMs subjected to 16h of high palmitate (HP) treatment develop the main features of IR, i.e., decreased insulin-stimulated glucose and FA uptake, as well as loss of endosomal acidification and insulin signaling. Taken together, these data propose that HP-treated hESC-CMs are a promising in vitro model of lipid overload-induced IR for further research into the underlying mechanism of cardiac IR and for identifying new pharmacological agents and therapeutic strategies. This article is part of a Special issue entitled Cardiac adaptations to obesity, diabetes and insulin resistance, edited by Professors Jan F.C. Glatz, Jason R.B. Dyck and Christine Des Rosiers.

Metabolic and Biochemical Stressors in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) or diabetes-induced cardiac dysfunction is a direct consequence of uncontrolled metabolic syndrome and is widespread in US population and worldwide. Despite of the heterogeneous and distinct features of DCM, the clinical relevance of DCM is now becoming established. DCM progresses to pathological cardiac remodeling with the higher risk of heart attack and subsequent heart failure in diabetic patients. In this review, we emphasize lipid substrate quality and the phenotypic, metabolic, and biochemical stressors of DCM in the rodent and human pathophysiology. We discuss lipoxygenase signaling in the inflammatory pathway with multiple contributing and confounding factors leading to DCM. Additionally, emerging biochemical pathways are emphasized to make progress toward therapeutic advancement to treat DCM.

Small heterodimer partner (SHP) contributes to insulin resistance in cardiomyocytes

Small heterodimer partner (SHP) is an atypical nuclear receptor expressed in heart that has been shown to inhibit the hypertrophic response. Here, we assessed the role of SHP in cardiac metabolism and inflammation. Mice fed a high-fat diet (HFD) displayed glucose intolerance accompanied by increased cardiac mRNA levels of Shp. In HL-1 cardiomyocytes, SHP overexpression inhibited both basal and insulin-stimulated glucose uptake and impaired the insulin signalling pathway (evidenced by reduced AKT and AS160 phosphorylation), similar to insulin resistant cells generated by high palmitate/high insulin treatment (HP/HI; 500μM/100nM). In addition, SHP overexpression increased Socs3 mRNA and reduced IRS-1 protein levels. SHP overexpression also induced Cd36 expression (~6.2 fold; p<0.001) linking to the observed intramyocellular lipid accumulation. SHP overexpressing cells further showed altered expression of genes involved in lipid metabolism, i.e., Acaca, Acadvl or Ucp3, augmented NF-κB DNA-binding activity and induced transcripts of inflammatory genes, i.e., Il6 and Tnf mRNA (~4-fold induction, p<0.01). Alterations in metabolism and inflammation found in SHP overexpressing cells were associated with changes in the mRNA levels of Ppara (79% reduction, p<0.001) and Pparg (~58-fold induction, p<0.001). Finally, co-immunoprecipitation studies showed that SHP overexpression strongly reduced the physical interaction between PPARα and the p65 subunit of NF-κB, suggesting that dissociation of these two proteins is one of the mechanisms by which SHP initiates the inflammatory response in cardiac cells. Overall, our results suggest that SHP upregulation upon high-fat feeding leads to lipid accumulation, insulin resistance and inflammation in cardiomyocytes.

Cardiac Abnormalities in Youth with Obesity and Type 2 Diabetes

Childhood obesity has been linked to cardiovascular disease (CVD) risk in adulthood. Of great concern is the expected increase in the population's CVD burden in relation to childhood obesity. This is compounded by the risk related to chronic hyperglycemia exposure in youth with type 2 diabetes. We herein provide an overview of the spectrum of early cardiovascular disease manifestation in youth with obesity and type 2 diabetes, in particular abnormalities in cardiac structure and function. Cardiac remodeling and adverse target organ damage is already evident in the pediatric age group in children with obesity and type 2 diabetes. This supports the importance of intensifying obesity prevention efforts and early intervention to treat comorbidities of obesity in the pediatric age group to prevent cardiac events in early adulthood.

Association of Gestational Diabetes Mellitus With Left Ventricular Structure and Function: The CARDIA Study

OBJECTIVE

Gestational diabetes mellitus (GDM) predicts incident cardiovascular disease (CVD). However, mechanisms linking GDM to CVD beyond intervening incident diabetes are not well understood. We examined the relation of GDM with echocardiographic parameters of left ventricular (LV) structure and function, which are important predictors of future CVD risk.

RESEARCH DESIGN AND METHODS

We studied 609 women (43% black) from the Coronary Artery Risk Development in Young Adults (CARDIA) study who delivered one or more births during follow-up and had echocardiograms in 1990-1991 (mean age 28.8 years) and 2010-2011.

RESULTS

During the 20-year follow-up, 965 births were reported, with GDM developing in 64 women (10.5%). In linear regression models adjusted for sociodemographic factors, BMI, physical activity, parity, smoking, use of oral contraceptives, alcohol intake, family history of coronary heart disease, systolic blood pressure, and lipid levels, women with GDM had impaired longitudinal peak strain (-15.0 vs. -15.7%, P = 0.025), circumferential peak strain (-14.8 vs. -15.6%, P = 0.028), lateral e' wave velocity (11.0 vs. 11.8 cm/s, P = 0.012), and septal e' wave velocity (8.6 vs. 9.3 cm/s, P = 0.015) in 2010-2011 and a greater 20-year increase in LV mass indexed to body surface area (14.3 vs. 6.0 g/m(2), P = 0.006) compared with women with non-GDM pregnancies. Further adjustment for incident type 2 diabetes after pregnancy did not attenuate these associations.

CONCLUSIONS

Pregnancy complicated by GDM is independently associated with increased LV mass and impaired LV relaxation and systolic function. Implementation of postpartum cardiovascular health interventions in women with a history of GDM may offer an additional opportunity to reduce future CVD risk.

Exercise Training Attenuates Upregulation of p47(phox) and p67(phox) in Hearts of Diabetic Rats

Exercise training (ExT) is currently being used as a nonpharmacological strategy to improve cardiac function in diabetic patients. However, the molecular mechanism(s) underlying its beneficial effects remains poorly understood. Oxidative stress is known to play a key role in the pathogenesis of diabetic cardiomyopathy and one of the enzyme systems that produce reactive oxygen species is NADH/NADPH oxidase. The goal of this study was to investigate the effect of streptozotocin- (STZ-) induced diabetes on expression of p47(phox) and p67(phox), key regulatory subunits of NADPH oxidase, in cardiac tissues and determine whether ExT can attenuate these changes. Four weeks after STZ treatment, expression of p47(phox) and p67(phox) increased 2.3-fold and 1.6-fold, respectively, in left ventricles of diabetic rats and these increases were attenuated with three weeks of ExT, initiated 1 week after onset of diabetes. In atrial tissues, there was increased expression of p47(phox) (74%), which was decreased by ExT in diabetic rats. Furthermore, increased collagen III levels in diabetic hearts (52%) were significantly reduced by ExT. Taken together, ExT attenuates the increased expression of p47(phox) and p67(phox) in the hearts of diabetic rats which could be an underlying mechanism for improving intracardiac matrix and thus cardiac function and prevent cardiac remodeling in diabetic cardiomyopathy.

Sympathovagal balance and 1-h postload plasma glucose in normoglucose tolerant hypertensive patients

AIMS

Normoglucose tolerant (NGT) subjects with a 1-h postload plasma glucose (PLPG) value ≥155 mg/dL have an increased risk of type-2 diabetes and subclinical organ damage. Heart rate variability (HRV) reflects cardiac autonomic balance, frequently impaired in course of diabetes. At this time, no data support the association between 1-h PLPG and HRV; thus, we investigated the possible association between 1-h PLPG and HRV.

METHODS

We enrolled 92 never-treated hypertensive subjects (56 women, 36 men), aged 55 ± 9.8 years. During OGTT, the patients underwent electrocardiographic recordings to evaluate HRV in the time domain (SDNN). Insulin sensitivity was assessed by Matsuda index.

RESULTS

Among participants, 56 were NGT, 20 had impaired glucose tolerance (IGT), and 16 had type-2 diabetes. According to the 1-h PLPG cutoff point of 155 mg/dL, we divided NGT subjects into: NGT < 155 (n = 38) and NGT ≥ 155 (n = 18). Glucose tolerance status was associated with a significant (P < 0.0001) increase in PLPG and insulin and the reduction in Matsuda index. In all groups, the SDNN values significantly (P < 0.0001) decreased during the first hour of OGTT. A complete recovery in NGT groups was observed at the end of the second hour; in IGT and type-2 diabetes, SDNN remained significantly lower with respect to baseline values. At multiple regression analysis, Matsuda index resulted in the only determinant of SDNN modification, explaining the 12.3 % of its variability.

CONCLUSIONS

Our data demonstrate that during OGTT, sympathovagal balance is acutely affected by both glucose and insulin modifications. Particularly, NGT ≥ 155 subjects behave in the same way of IGT and type-2 diabetes patients.

Ryanodine receptor phosphorylation by CaMKII promotes spontaneous Ca(2+) release events in a rodent model of early stage diabetes: The arrhythmogenic substrate

BACKGROUND

Heart failure and arrhythmias occur more frequently in patients with type 2 diabetes (T2DM) than in the general population. T2DM is preceded by a prediabetic condition marked by elevated reactive oxygen species (ROS) and subclinical cardiovascular defects. Although multifunctional Ca2+ calmodulin-dependent protein kinase II (CaMKII) is ROS-activated and CaMKII hyperactivity promotes cardiac diseases, a link between prediabetes and CaMKII in the heart is unprecedented.

OBJECTIVES

To prove the hypothesis that increased ROS and CaMKII activity contribute to heart failure and arrhythmogenic mechanisms in early stage diabetes.

METHODS-RESULTS

Echocardiography, electrocardiography, biochemical and intracellular Ca2+ (Ca2+i) determinations were performed in fructose-rich diet-induced impaired glucose tolerance, a prediabetes model, in rodents. Fructose-rich diet rats showed decreased contractility and hypertrophy associated with increased CaMKII activity, ROS production, oxidized CaMKII and enhanced CaMKII-dependent ryanodine receptor (RyR2) phosphorylation compared to rats fed with control diet. Isolated cardiomyocytes from fructose-rich diet showed increased spontaneous Ca2+i release events associated with spontaneous contractions, which were prevented by KN-93, a CaMKII inhibitor, or addition of Tempol, a ROS scavenger, to the diet. Moreover, fructose-rich diet myocytes showed increased diastolic Ca2+ during the burst of spontaneous Ca2+i release events. Mice treated with Tempol or with sarcoplasmic reticulum-targeted CaMKII-inhibition by transgenic expression of the CaMKII inhibitory peptide AIP, were protected from fructose-rich diet-induced spontaneous Ca2+i release events, spontaneous contractions and arrhythmogenesis in vivo, despite ROS increases.

CONCLUSIONS

RyR2 phosphorylation by ROS-activated CaMKII, contributes to impaired glucose tolerance-induced arrhythmogenic mechanisms, suggesting that CaMKII inhibition could prevent prediabetic cardiovascular complications and/or evolution.

Present Insights on Cardiomyopathy in Diabetic Patients

The pathogenesis of diabetic cardiomyopathy (DCM) is partially understood and is likely to be multifactorial, involving metabolic disturbances, hypertension and cardiovascular autonomic neuropathy (CAN). Therefore, an important need remains to further delineate the basic mechanisms of diabetic cardiomyopathy and to apply them to daily clinical practice. We attempt to detail some of these underlying mechanisms, focusing in the clinical features and management. The novelty of this review is the role of CAN and reduction of blood pressure descent during sleep in the development of DCM. Evidence has suggested that CAN might precede left ventricular hypertrophy and diastolic dysfunction in normotensive patients with type 2 diabetes, serving as an early marker for the evaluation of preclinical cardiac abnormalities. Additionally, a prospective study demonstrated that an elevation of nocturnal systolic blood pressure and a loss of nocturnal blood pressure fall might precede the onset of abnormal albuminuria and cardiovascular events in hypertensive normoalbuminuric patients with type 2 diabetes. Therefore, existing microalbuminuria could imply the presence of myocardium abnormalities. Considering that DCM could be asymptomatic for a long period and progress to irreversible cardiac damage, early recognition and treatment of the preclinical cardiac abnormalities are essential to avoid severe cardiovascular outcomes. In this sense, we recommend that all type 2 diabetic patients, especially those with microalbuminuria, should be regularly submitted to CAN tests, Ambulatory Blood Pressure Monitoring and echocardiography, and treated for any abnormalities in these tests in the attempt of reducing cardiovascular morbidity and mortality.

Individuals with impaired glucose tolerance demonstrate normal cardiac sympathetic innervation using I-123 mIBG scintigraphy

BACKGROUND

Impaired glucose tolerance (IGT) is associated with an increased risk of type 2 diabetes (T2DM) and cardiovascular disease. Some but not all studies have reported cardiac autonomic dysfunction in subjects with IGT and there is only one direct study of cardiac innervation in subjects with IGT. The purpose of this study was to assess global and regional cardiac sympathetic innervation and cardiac autonomic function in individuals with IGT.

METHODS AND RESULTS

We undertook (123)I-mIBG scintigraphy and cardiac autonomic function in 15 subjects with IGT and 15 age and sex-matched healthy controls. Early heart to mediastinum ratio (HMR) (1.71 ± 0.17 vs 1.67 ± 0.13, P = .49), late HMR (1.73 ± 0.18 vs 1.73 ± 0.16, P = .97) and washout rate (WR) (18.6 ± 4.2 vs 19.1 ± 7.6%, P = .84), did not differ between subjects with IGT and control subjects. More detailed regional analysis revealed reduced tracer uptake at the apex, base and inferior wall in all subjects and the anterior wall in a minority of subjects. There were no differences in total score (56.6 ± 4.0 vs 53.3 ± 8.4, P = .193), modified score (48.5 ± 3.3 vs 46.2 ± 6.0, P = .215), anterior wall score (10.2 ± 1.3 vs 10.1 ± 1.6, P = .898), inferior wall score (8.9 ± 1.9 vs 7.7 ± 2.6, P = .163), basal score (18.7 ± 1.9 vs 18.2 ± 3.3, P = .636) and tests of cardiac autonomic function between the groups.

CONCLUSION

Global and regional measures of MIBG uptake and washout as well as cardiac autonomic function did not differ between subjects with IGT and healthy controls.

New-onset diabetes and glucose regulation are significant determinants of left ventricular hypertrophy in renal transplant recipients

BACKGROUND

New-onset diabetes after transplantation (NODAT) is associated with decreased graft survival and an increased risk for cardiovascular disease. The objective of this study was to evaluate the risk factors for development of NODAT and its' relationship with arterial stiffness and left ventricular mass index (LVMI) in kidney transplant recipients.

METHODS

159 kidney transplant recipients were selected from our transplantation center who underwent renal transplantation between years 2007 and 2010.

RESULTS

Among 159 patients, 57 (32.2%) patients were with NODAT who were significantly older than patients without diabetes (P: 0.0001). Patients with NODAT had significantly higher pulse wave velocity (PWv) (P: 0.033) and left ventricular mass index LVMI (P: 0.001) compared to patients without NODAT. Further analysis was done according to LVMI as follows: LVMI > 130 g/m(2) (n: 57) and LVMI ≤ 130 g/m(2) (n: 102). We observed higher office systolic and diastolic BP, serum trygliceride, glucose, creatinine, age, and HbA1c (P: 0.0001) levels in patients with LVMI > 130 g/m(2). Linear regression analysis revealed that HbA1c was the major determinant of LVMI (P: 0.026, β: 0.361).

CONCLUSIONS

HbA1c is the major determinant of LVMI, so strict control of serum glucose levels is essential for preventing cardiovascular disease in patients with NODAT.

Insulin-resistance HCV infection-related affects vascular stiffness in normotensives

BACKGROUND AND AIMS. Arterial stiffness evaluated as pulse wave velocity, is an early marker of vascular damage and an independent predictor for cardiovascular events. We investigated if the insulin resistance/hyperinsulinemia chronic hepatitis C virus infection-related could influence arterial stiffness. METHODS. We enrolled 260 outpatients matched for age, body mass index, gender, ethnicity: 52 with never-treated uncomplicated chronic hepatitis C virus infection (HCV(+)), 104 never-treated hypertensives (HT) and 104 healthy subjects (NT). Pulse wave velocity was evaluated by a validated system employing high-fidelity applanation tonometry. We also measured: fasting plasma glucose and insulin, total, LDL- and HDL-cholesterol, triglyceride, creatinine, e-GFR-EPI, HOMA, quantitative HCV-RNA. RESULTS. HCV(+) patients with respect to NT had an increased pulse wave velocity (7.9 ± 2.1 vs 6.4 ± 2.1 m/s; P < 0.0001), similar to that observed in HT group (8.8 ± 3.2 m/s). HCV(+) patients, in comparison with NT, had higher triglyceride, creatinine, fasting insulin and HOMA (3.2 ± 1.3 vs 2.5 ± 1.0; P < 0.0001). At linear regression analysis, the correlation between pulse wave velocity and HOMA was similar in HT (r = 0.380, P < 0.0001) and HCV(+) (r = 0.369, P = 0.004) groups. At multiple regression analysis, HOMA resulted the major determinant of pulse wave velocity in all groups, explaining respectively 11.8%, 14.4% and 13.6% of its variation in NT, HT and HCV(+). At correlational analysis hepatitis C virus-RNA and HOMA demonstrated a strong and linear relationship between them, explaining the 72.4% of their variation (P = 0.022). CONCLUSIONS. We demonstrated a significant and direct correlation between HOMA and pulse wave velocity in HCV(+) patients, similar to that observed in hypertensives.

Fibrosis and heart failure

The extracellular matrix (ECM) is a living network of proteins that maintains the structural integrity of the myocardium and allows the transmission of electrical and mechanical forces between the myocytes for systole and diastole. During ventricular remodeling, as a result of iterations in the hemodynamic workload, collagen, the main component of the ECM, increases and occupies the areas between the myocytes and the vessels. The resultant fibrosis (reparative fibrosis) is initially a compensatory mechanism and may progress adversely influencing tissue stiffness and ventricular function. Replacement fibrosis appears at sites of previous cardiomyocyte necrosis to preserve the structural integrity of the myocardium, but with the subsequent formation of scar tissue and widespread distribution, it has adverse functional consequences. Continued accumulation of collagen impairs diastolic function and compromises systolic mechanics. Nevertheless, the development of fibrosis is a dynamic process wherein myofibroblasts, the principal cellular elements of fibrosis, are not only metabolically active and capable of the production and upregulation of cytokines but also have contractile properties. During the process of reverse remodeling with left ventricular assist device unloading, cellular, structural, and functional improvements are observed in terminal heart failure patients. With the advent of anti-fibrotic pharmacologic therapies, cellular therapy, and ventricular support devices, fibrosis has become an important therapeutic target in heart failure patients. Herein, we review the current concepts of fibrosis as a main component of ventricular remodeling in heart failure patients. Our aim is to integrate the histopathologic process of fibrosis with the neurohormonal, cytochemical, and molecular changes that lead to ventricular remodeling and its physiologic consequences in patients. The concept of fibrosis as living scar allows us to envision targeting this scar as a means of improving ventricular function in heart failure patients.

Chronic HCV infection increases cardiac left ventricular mass index in normotensive patients

BACKGROUND & AIMS

Left ventricular hypertrophy (LVH), is an independent predictor for cardiovascular events. We investigated if chronic hepatitis C virus (HCV) infection and the related insulin resistance (IR)/hyperinsulinemia could influence the increase of left ventricular mass (LVM).

METHODS

We enrolled 260 outpatients matched for age, body mass index, gender, ethnicity: 52 with never-treated uncomplicated chronic HCV infection (HCV(+)), 104 never-treated hypertensives (HT) and 104 healthy subjects (NT). LVM was calculated according to the Devereux formula and indexed for body surface area. The following laboratory parameters were measured: fasting plasma glucose and insulin, total, LDL- and HDL-cholesterol, triglyceride, creatinine, e-GFR-EPI, HOMA. Quantitative HCV-RNA was assessed by PCR.

RESULTS

HCV(+) patients with respect to healthy normotensive subjects had an increased LVMI (100 ± 23 vs. 83 ± 15 g/m(2); p < 0.0001), similar to that observed in HT group (103 ± 25 g/m(2)). Regarding biochemical variables, HCV(+) patients, in comparison with normotensive healthy subjects, had higher triglyceride, creatinine, fasting insulin and HOMA (3.2 ± 1.3 vs. 2.5 ± 1.0; p < 0.0001). At linear regression analysis, the correlation between LVMI and HOMA was similar in HT (r = 0.528, p < 0.0001) and HCV(+) (r = 0.489, p < 0.0001) groups. At multiple regression analysis, HOMA resulted the major determinant of LMVI in all groups, explaining respectively 21.8%, 27.8%, and 23.9% of its variation in NT, HT and HCV(+). At correlational analysis HCV-RNA and HOMA demonstrated a strong and linear relationship between them, explaining the 72.4% of their variation (p = 0.022).

CONCLUSIONS

We demonstrated a significant and direct correlation between HOMA and LVMI in patients with chronic HCV infection, similar to that observed in hypertensives.

Dietary patterns and 1-h post-load glucose in essential hypertension

BACKGROUND AND AIMS

Normoglucosetolerants (NGT) are considered at low risk, even if a 1-h post-load glucose (PLG) value ≥ 155 mg dl(-1) identifies NGTs at high risk of type-2 diabetes (T2D) and sub-clinical organ damage. Specific dietary factors may affect insulin sensitivity and the risk of T2D. However, it is unknown whether dietary components affect 1-h PLG in hypertensive NGT. Therefore, we investigate the effect of dietary patterns on 1-h PLG.

METHODS AND RESULTS

We selected 188 subjects (94 NGTs < 155 mg dl(-1) and 94 NGTs ≥ 155 mg dl(-1) PLG), well matched for age, gender and body mass index (BMI). Insulin sensitivity was evaluated using the Matsuda index. Dietary intake was quantified by a semiquantitative food frequency questionnaire (FEQ) validated in the European Investigation into Cancer and Nutrition (EPIC) study. The NGT ≥ 155 group had significantly reduced insulin sensitivity (40.3 ± 19.8 vs. 73.3 ± 28.8; P < 0.0001). With the exclusion of total calories, lipids, alcohol and fiber consumption we observed a significant difference, between groups, in starch (214.1 ± 52.4 vs. 268.8 ± 71.8 g; P < 0.0001), saturated (27.4 ± 8.7 vs. 24.1 ± 8.5 g; P = 0.009), monounsaturated (45.5 ± 8.9 vs. 48.8 ± 10.7 g; P = 0.023) and polyunsaturated fatty acids (FAs) (14.5 ± 4.0 vs. 16.8 ± 4.7 g; P < 0.0001), fructose (14.5 ± 5.3 vs. 11.2 ± 4.8 g; P < 0.0001), and oligosaccharides (103.2 ± 26.6 vs. 89.9 ± 29.2 g; P = 0.001) consumption. In the whole population, starch was the major predictor of 1-h PLG, explaining 23.2% of variation (P < 0.0001). In the NGT < 155 group, fructose was the strongest predictor, accounting for 15.4% of the variation; BMI, gender and polyunsaturated FAs added another 6.6%, 3.6% and 3.2%, respectively. In the NGT ≥ 155 group, saturated and polyunsaturated FAs were retained as the major predictors of 1-h PLG, explaining 18.2% and 11.4% of the variation.

CONCLUSIONS

The present data demonstrate that dietary patterns affect 1-h PLG, remarking the importance of both quantitative and qualitative composition of a diet.

The prevalence of diabetic cardiomyopathy: a population-based study in Olmsted County, Minnesota

BACKGROUND

Diabetic cardiomyopathy defined as either systolic or diastolic dysfunction in otherwise healthy diabetic persons is not clearly understood. The prevalence and outcomes of this disease in a community-based population have not been defined.

METHODS AND RESULTS

Cross-sectional survey of 2042 randomly selected residents of Olmsted County, Minnesota, aged 45 years or older between June 1997 and September 2000. All patients underwent Doppler echocardiographic assessment of systolic and diastolic function. Diabetic cardiomyopathy was defined in a person with diabetes and any systolic or at least moderate diastolic dysfunction without a history of coronary disease, hypertension, significant valvular disease, or congenital heart disease. The diagnosis of diabetic cardiomyopathy was made in 23 people, corresponding to a community population prevalence rate of 1.1%. Among diabetic patients, 16.9% met criteria for diabetic cardiomyopathy and 54.4% had diastolic dysfunction. Diabetes was associated with a 1.9-fold increase in risk of any left ventricular dysfunction, a 1.7-fold increase in risk of diastolic dysfunction, and a 2.2-fold increase in risk of systolic dysfunction. Among patients with diabetic cardiomyopathy, the cumulative probability of death was 18%, development of heart failure was 22%, and development of death or heart failure was 31% at 9 years.

CONCLUSION

Diabetic cardiomyopathy is relatively common in the community with a prevalence of 1.1%. The morbidity and mortality of patients with diabetic cardiomyopathy is high.

Hydrogen sulfide inhibits high-glucose-induced apoptosis in neonatal rat cardiomyocytes

Hydrogen sulfide (H2S), an endogenous signaling molecule with potent cytoprotective effects, has been shown to provide cardioprotection in various models of cardiac injury. The present study was designed to investigate the protective effects of H2S against high-glucose-induced cardiomyocyte apoptosis and explore the potential mechanisms using cultured neonatal rat cardiomyocytes. The apoptotic rate of cardiomyocytes was determined by flow cytometry with Annexin V/propidium iodide staining. Oxidative stress was evaluated by detecting concentration of malondialdehyde and superoxide dismutase in the supernatant of culture media. The mRNA and protein expression of Bax and Bcl-2 was determined by realtime PCR and Western blotting. Our findings suggested that H2S could protect against cardiomyocyte apoptosis induced by high glucose. Moreover, H2S was also found to reduce high-glucose-induced oxidative stress and alter the mRNA and protein expression of Bax and Bcl-2. In conclusion, our study demonstrates that H2S protects against high-glucose-induced cardiomyocyte apoptosis by attenuating oxidative stress and altering apoptosis regulatory gene expression.

Asymptomatic obese hypertensives and need of routine echocardiography for left ventricular mass assessment and treatment

BACKGROUND

Echocardiographic determination of Left Ventricle Mass (LVM) - an important marker of cardiovascular disease, has been given a lot of importance in clinical diagnosis and in planning of treatment. Clinically asymptomatic compensated hypertensives show some pathological findings which are indicative of left ventricular dysfunction.

METHODS

The study population of 106 males, after a detailed clinical examination, were evaluated by echocardiography and were classified as per the body mass index classification of WHO Western Pacific Region in 2000 for Asian population. Fasting blood samples were taken to estimate blood sugar and lipid profile.

RESULTS

It was observed that subjects in normal range of body mass index <45 years (23.68%) and >45 years (16.1%), subjects of overweight <45 years (15.7%) and >45 years (10.29%) and obese I and II<45 years (60.52%) and >45 years (73.52%). The comparison between left ventricular mass which was indexed to height(2.7) in subjects who were <45 years and >45years was observed to be statistically significant (p<0.03). On comparing LVM/ht(2.7) of normal BMI group with that of those with higher BMIs, it was noted to be significantly different (p<0.009), which was suggestive of adverse effects of increasing BMI on LVM. It was also observed that persons with increased BMIs showed changes in left ventricular geometry - 30.13% had concentric hypertrophy, 17.80% had concentric remodeling, 8.21% had eccentric hypertrophy and that 38.35% had normal left ventricle geometry.

CONCLUSION

The present study therefore, indicated that it was better to do an echocardiographic screening of asymptomatic subjects who had even a marginal increase in blood pressure and BMI, to diagnose potential cardiac dysfunction.

Update on the pathophysiological activities of the cardiac molecule cardiotrophin-1 in obesity

Cardiotrophin-1 (CT-1) is a heart-targeting cytokine that has been reported to exert a variety of activities also in other organs such as the liver, adipose tissue, and atherosclerotic arteries. CT-1 has been shown to induce these effects via binding to a transmembrane receptor, comprising the leukaemia inhibitory factor receptor (LIFR β ) subunit and the glycoprotein 130 (gp130, a common signal transducer). Both local and systemic concentrations of CT-1 have been shown to potentially play a critical role in obesity. For instance, CT-1 plasma concentrations have been shown to be increased in metabolic syndrome (a cluster disease including obesity) probably due to adipose tissue overexpression. Interestingly, treatment with exogenous CT-1 has been shown to improve lipid and glucose metabolism in animal models of obesity. These benefits might suggest a potential therapeutic role for CT-1. However, beyond its beneficial properties, CT-1 has been also shown to induce some adverse effects, such as cardiac hypertrophy and adipose tissue inflammation. Although scientific evidence is still needed, CT-1 might be considered as a potential example of damage/danger-associated molecular pattern (DAMP) in obesity-related cardiovascular diseases. In this narrative review, we aimed at discussing and updating evidence from basic research on the pathophysiological and potential therapeutic roles of CT-1 in obesity.

Diabetic cardiomyopathy: understanding the molecular and cellular basis to progress in diagnosis and treatment

Diabetes mellitus is an important and prevalent risk factor for congestive heart failure. Diabetic cardiomyopathy has been defined as ventricular dysfunction that occurs in diabetic patients independent of a recognized cause such as coronary artery disease or hypertension. The disease course consists of a hidden subclinical period, during which cellular structural insults and abnormalities lead initially to diastolic dysfunction, later to systolic dysfunction, and eventually to heart failure. Left ventricular hypertrophy, metabolic abnormalities, extracellular matrix changes, small vessel disease, cardiac autonomic neuropathy, insulin resistance, oxidative stress, and apoptosis are the most important contributors to diabetic cardiomyopathy onset and progression. Hyperglycemia is a major etiological factor in the development of diabetic cardiomyopathy. It increases the levels of free fatty acids and growth factors and causes abnormalities in substrate supply and utilization, calcium homeostasis, and lipid metabolism. Furthermore, it promotes excessive production and release of reactive oxygen species, which induces oxidative stress leading to abnormal gene expression, faulty signal transduction, and cardiomyocytes apoptosis. Stimulation of connective tissue growth factor, fibrosis, and the formation of advanced glycation end-products increase the stiffness of the diabetic hearts. Despite all the current information on diabetic cardiomyopathy, translational research is still scarce due to limited human myocardial tissue and most of our knowledge is extrapolated from animals. This paper aims to elucidate some of the molecular and cellular pathophysiologic mechanisms, structural changes, and therapeutic strategies that may help struggle against diabetic cardiomyopathy.

Cardiovascular characteristics in subjects with increasing levels of abnormal glucose regulation: the Strong Heart Study

OBJECTIVE

To evaluate whether impaired fasting glucose (IFG) or the combination of IFG and impaired glucose tolerance (IGT) is associated with progressive abnormalities of cardiac geometry and function.

RESEARCH DESIGN AND METHODS

We studied 562 nondiabetic (311 women), nonhypertensive participants of the second Strong Heart Study exam, without prevalent cardiovascular (CV) disease and with estimated glomerular filtration rate ≥60 mL/min/1.73 m(2) (age 46-65 years, 198 with isolated IFG [35%], and 132 with combined IFG and IGT [23%]). Anthropometric parameters, insulin resistance, fibrinogen, C-reactive protein (CRP), lipid profile, blood pressure (BP), and echocardiographic parameters were compared with 232 participants with normal glucose tolerance (NGT).

RESULTS

BMI, prevalence of central obesity, homeostatic model assessment index of insulin resistance, plasma triglycerides, fibrinogen, and CRP increased progressively across categories of glucose intolerance (P < 0.0001), with the IFG+IGT group having higher values than those with isolated IFG (0.05 < P < 0.0001). Compared with NGT, both IFG and IFG+IGT exhibited greater left ventricular (LV) mass (P < 0.0001) and lower Doppler early peak rapid filling velocity to peak atrial filling velocity ratio (P < 0.005), without differences in LV systolic function. The odds of LV hypertrophy (LV mass index >46.7 in women or >49.2 g/m(2.7) in men) was 3.5 in IFG participants (95% CI 0.68-17.76; P = NS) and 9.76 (2.03-46.79; P = 0.004) in IFG+IGT, compared with NGT, after adjustment for age, sex, heart rate, systolic BP, and waist circumference (WC). In the overall sample, LV mass index was associated with WC (P = 0.033), CRP (P = 0.027), and 2-h oral glucose tolerance test (P = 0.001) independently of confounders.

CONCLUSIONS

Cardiometabolic profile and markers of inflammation are more severely altered in men and women with both IFG and IGT compared with those with IFG alone. These individuals, in the absence of hypertension, have a 10-fold greater probability of preclinical CV disease (LV hypertrophy).

Evolution of left ventricular mass in renal transplant recipients: the influence of glucose homeostasis and oxidative stress

BACKGROUND

Left ventricular hypertrophy, considered an independent factor for cardiovascular mortality, is frequent among renal transplant recipients (RTR), in whom we investigated changes in left ventricular mass (LVM) after grafting and associations with possible causal factors, especially glucose metabolism and oxidative stress.

METHODS

We performed a prospective study of 37 RTR without prior diabetes mellitus who were evaluated at three times after transplantation (medians of 0.6, 16 and 28 months) by means of the LVM index (LVMI, echocardiographic measure of LVM related to body surface area, g/m(2)), oral glucose tolerance test and determinations of malondialdehyde and total glutathione (GSH), as well as glomerular filtration rate (GFR) estimate by the Modification of Diet in Renal Disease formula. We calculated the overall increment (DeltaLVMI) and percent change of LVMI. Patients were diagnosed to be prediabetic (PD) or new-onset diabetes after transplant (NODAT) according to ADA criteria.

RESULTS

The mean LVMI decreased significantly over time among whole group baseline = 108.34 ± 27.71 g/m(2) versus middle: 100.03 ± 27.53 g/m(2) versus final: 90.62 ± 24.06 g/m(2) (P = .000). However, 13.5% of subjects showed an increased LVMI and 59.5%, a decrease less than 20%. Patients with NODAT at the end of the study showed a positive DeltaLVMI, which was negative in nondiabetics (0.24 ± 16.14 versus -19.86 ± 12.61 g/m(2), P = .018). Compared with DeltaLVMI(-) recipients, patients with DeltaLVMI(+) showed a greater proportion of PD and NODAT at baseline (60% and 40% versus 18.8% and 12.5%, P = .017), and significantly higher all-time fasting glycemia, lower estimated GFR, and greater increments of malondialdehyde and GSH over time. Those with a <20% LVMI decrease experienced progressive GFR impairment over time, as opposed to those with an LVMI decrease > 20%, who showed greater and improving GFR over the whole study.

CONCLUSIONS

LVMI does not always improve in RTR; the evolution of ventricular mass after renal transplantation is influenced by glucose metabolism disorders, oxidative stress, and graft function.