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

One-hour post-load glucose levels are associated with hepatic steatosis assessed by transient elastography

AIM

To examine the association between 1-hour plasma glucose (PG) concentration and markers of non-alcoholic fatty liver disease (NAFLD) assessed by transient elastography (TE).

METHODS

We performed TE in 107 metabolically well-characterized non-diabetic White individuals. Controlled attenuation parameter (CAP) was used to quantify liver steatosis, while liver stiffness marker (LS) was used to evaluate fibrosis.

RESULTS

Controlled attenuation parameter correlated significantly with 1-hour PG (r = 0.301, P < 0.01), fasting insulin (r = 0.285, P < 0.01), 2-hour insulin (r = 0.257, P < 0.02), homeostasis model assessment index of insulin resistance (r = 0.252, P < 0.01), high-density lipoprotein cholesterol (r = -0.252, P < 0.02), body mass index (BMI; r = 0.248, P < 0.02) and age (r = 0.212, P < 0.03), after correction for age, sex and BMI. In a multivariable linear regression analysis, 1-hour PG (β = 0.274, P = 0.008) and fasting insulin levels (β = 0.225, P = 0.029) were found to be independent predictors of CAP. After excluding subjects with prediabetes, 1-hour PG was the sole predictor of CAP variation (β = 0.442, P < 0.001). In a logistic regression model, we observed that the group with 1-hour PG ≥  8.6 mmol/L (155 mg/dL) had a significantly higher risk of steatosis (odds ratio 3.98, 95% confidence interval 1.43-11.13; P = 0.008) than individuals with 1-hour PG <  8.6 mmol/L, after correction for potential confounders. No association was observed between 1-hour PG and LS.

CONCLUSION

Our data confirm that 1-hour PG ≥  8.6 mmol/L is associated with higher signs of NAFLD, even among individuals with normal glucose tolerance, categorized as low risk by canonical diagnostic standards. TE is a safe low-impact approach that could be employed for stratifying the risk profile in these patients, with a high level of accuracy.

Association between epicardial adipose tissue and myocardial work by non-invasive left ventricular pressure-strain loop in people with suspected metabolic syndrome

Given the inconsistent results on the prognostic significance of epicardial adipose tissue (EAT), the purpose of the present study was to investigate the association of EAT thickness and myocardial work by non-invasive left ventricular pressure-strain loop in people with suspected metabolic syndrome (MS). A total of 194 participants imaged with echocardiography were evaluated. In accordance with the median EAT thickness, MS patients fell into thin EAT group and thick EAT group. Conventional echocardiographic parameters, global longitudinal strain (GLS) and the global myocardial work parameters obtained by pressure-strain loop analysis, comprising the global work index (GWI), global work efficiency (GWE), global constructive work (GCW) and global wasted work (GWW) were compared between the two groups. In comparison with the thin EAT group, thick EAT group achieved significantly higher values in interventricular septal thickness, end-diastolic left ventricular posterior wall thickness, left ventricular mass index and GWW (p < 0.05). while the absolute value of GLS, GWI, GCW, and GWE were notably lower in the thick EAT group (p < 0.001). EAT thickness showed a significant correlation with GWI and GCW (r = - 0.328, p = 0.001; r = - 0.253, p = 0.012), and also independently correlated with GWI and GCW in the multivariate regression analysis (β = - 0.310, p = 0.001; β = - 0.199, p = 0.049). EAT thickness is associated with left ventricular myocardial function in subjects with suspected metabolic syndrome, independently of other risk factors. Further studies are supposed to ensure the causal associations and related mechanisms.

Genetic Determinants of Body Mass Index and Fasting Glucose Are Mediators of Grade 1 Diastolic Dysfunction

Background Early (grade 1) cardiac left ventricular diastolic dysfunction (G1DD) increases the risk for heart failure with preserved ejection fraction and may improve with aggressive risk factor modification. Type 2 diabetes, obesity, hypertension, and coronary heart disease are associated with increased incidence of diastolic dysfunction. The genetic drivers of G1DD are not defined. Methods and Results We curated genotyped European ancestry G1DD cases (n=668) and controls with normal diastolic function (n=1772) from Vanderbilt's biobank. G1DD status was explored through (1) an additive model genome-wide association study, (2) shared polygenic risk through logistic regression, and (3) instrumental variable analysis using 2-sample Mendelian randomization (the inverse-variance weighted method, Mendelian randomization-Egger, and median) to determine potential modifiable risk factors. There were no common single nucleotide polymorphisms significantly associated with G1DD status. A polygenic risk score for BMI was significantly associated with increased G1DD risk (odds ratio [OR], 1.20 for 1-SD increase in BMI [95% CI, 1.08-1.32]; P=0.0003). The association was confirmed by the inverse-variance weighted method (OR, 1.89 [95% CI, 1.37-2.61]). Among the candidate mediators for BMI, only fasting glucose was significantly associated with G1DD status by the inverse-variance weighted method (OR, 4.14 for 1-SD increase in fasting glucose [95% CI, 1.55-11.02]; P=0.005). Multivariable Mendelian randomization showed a modest attenuation of the BMI association (OR, 1.84 [95% CI, 1.35-2.52]) when adjusting for fasting glucose. Conclusions These data suggest that a genetic predisposition to elevated BMI increases the risk for G1DD. Part of this effect may be mediated through altered glucose homeostasis.

Air Pollution in American Indian Versus Non-American Indian Communities, 2000-2018

Objectives. To compare fine particulate matter (PM2.5) concentrations in American Indian (AI)-populated with those in non-AI-populated counties over time (2000-2018) in the contiguous United States. Methods. We used a multicriteria approach to classify counties as AI- or non--AI-populated. We ran linear mixed effects models to estimate the difference in countywide annual PM2.5 concentrations from well-validated prediction models and monitoring sites (modeled and measured PM2.5, respectively) in AI- versus non-AI-populated counties. Results. On average, adjusted modeled PM2.5 concentrations in AI-populated counties were 0.38 micrograms per cubic meter (95% confidence interval [CI] = 0.23, 0.54) lower than in non-AI-populated counties. However, this difference was not constant over time: in 2000, modeled concentrations in AI-populated counties were 1.46 micrograms per cubic meter (95% CI = 1.25, 1.68) lower, and by 2018, they were 0.66 micrograms per cubic meter (95% CI = 0.45, 0.87) higher. Over the study period, adjusted modeled PM2.5 mean concentrations decreased by 2.13 micrograms per cubic meter in AI-populated counties versus 4.26 micrograms per cubic meter in non-AI-populated counties. Results were similar for measured PM2.5. Conclusions. This study highlights disparities in PM2.5 trends between AI- and non-AI-populated counties over time, underscoring the need to strengthen air pollution regulations and prevention implementation in tribal territories and areas where AI populations live. (Am J Public Health. 2022;112(4): 615-623. https://doi.org/10.2105/AJPH.2021.306650).

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.

Obesity cardiomyopathy: evidence, mechanisms, and therapeutic implications

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

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.

Triglycerides are related to left ventricular mass in hypertensive patients independently of other cardiometabolic risk factors: the effect of gender

Given the inconsistent results on the prognostic significance of triglycerides (TGs), the purpose of the present study was to investigate the association of plasma TGs with left ventricular mass (LVM) in hypertensive patients. We studied 760 never treated, non diabetic, hypertensive patients. Τransthoracic echocardiography was performed and LVMI was calculated according to the Devereux formula, adjusted to body surface area. Triglycerides were associated with LVMI after adjustment for age, gender, systolic blood pressure (SBP), smoking and fasting glucose (b = 0.08, p = 0.009). This relationship remained significant even after adjustment for BMI, LDL-C and ApoB/ApoA1 ratio (b = 0.07, p = 0.04). Gender-stratified analysis indicated that TGs were related to LVMI in men (p = 0.001) but not in women (p = NS). In addition, TGs were related with LV hypertrophy (LVH) in men, increasing the odds by 7% to present LVMI over 115 g/m² (OR = 1.07 per 10 mg/dl increase in TGs, p = 0.01). In conclusion, TGs are associated with LVMI in hypertensive patients, independently of other risk factors, including LDL-C. Given the prognostic significance of LVH, it might be suggested that TGs may serve as a useful marker for indentifying hypertensive patients at high risk. The gender discrepancy may suggest a possible gender-specific modulatory effect of TGs on LV structure.

An Overall Glance of Evidence Supportive of One-Hour and Two-Hour Postload Plasma Glucose Levels as Predictors of Long-Term Cardiovascular Events

This review summarizes the vast literature describing the long-term epidemiological studies with emphasis on postprandial glucose as a stronger predictor of cardiovascular complications as compared to fasting glucose and HbA1c. Many molecular studies also supported this fact by illustrating that postchallenge hyperglycemia is associated with elevated biomarkers of systemic inflammation in the plasma and thus increasing the chances of vascular damage. Large-scale studies have proved that vascular stiffness, brachial-ankle pulse-wave velocity, carotid intima thickness, and left ventricular hypertrophy have been associated with postprandial glucose as compared to fasting glucose or glycosylated hemoglobin.

HYPOCALCEMIC CARDIOMYOPATHY - A RARE HEART FAILURE ETIOLOGY IN ADULT

Introduction

Heart failure and dilated cardiomyopathy (DCM) in adults are rarely caused by hypoparathyroidism induced hypocalcemia.

Case report

Female patient, 40 years old, diabetic, with previous history of thyroidectomy for Graves' disease, was hospitalized for syncope and symptoms of heart failure. ECG revealed sinus tachycardia, long QT, negative T from V1 up to V4. Chest X-ray, cardiac ultrasound and contrast cardiac MRI confirmed dilated left chambers, severe systolic dysfunction of the left ventricle (left ventricle ejection fraction=15%) due to diffuse hypokinesia and restrictive type of diastolic dysfunction. Patient status insignificantly improved with specific heart failure depletion treatment but important signs of hypocalcemia occurred. Low levels of total and ionic serum calcium were detected (total serum calcium 3.6 mg/dL, ionic calcium=2.2 mg/dL) along with low serum levels of parathormone (10 pg/mL) and high level of phosphatemia (6.4 mg/dL). After one month of parenteral treatment with calcium and oral vitamin D, hypocalcemic signs disappeared and heart failure significantly improved.

Conclusion

This rare adult condition is refractory to heart failure conventional therapy but promptly responds to restoration of normocalcemia. It is important to be aware of this pathophysiological setting, in order to treat it correctly.

Cardiac function is not associated with glucose control in older women

The present study evaluated the effect of age on glucose tolerance and cardiac function and assessed the relationship between metabolic control and cardiac function and performance. Thirty-four healthy women aged 40 to 81 years were divided into two age groups: younger (≤50 years of age, N = 19) and older (≥60 years of age, N = 15). Participants performed an oral glucose tolerance test and a graded cardiopulmonary exercise test with non-invasive haemodynamic measurements. Compared to younger, older women demonstrated significantly higher 2-hour glucose (4.67 ± 1.01 vs 6.08 ± 1.54 mmol/l, P < 0.01), but lower peak exercise O₂ consumption (1.96 ± 0.44 vs 1.38 ± 0.26 l/min, P < 0.01) and cardiac power output (4.06 ± 0.76 vs 3.35 ± 0.73 W, P = 0.01). When data from all study participants were combined, there was a significant negative relationship between 2-hour glucose and peak cardiac power (r = -0.39, P = 0.02), and peak O₂ consumption (r = -0.40, P = 0.02). The strength of these relationships was affected by age, with moderate negative relationship identified between 2-hour glucose and peak cardiac power output in younger compared to older participants (r = -0.38, P = 0.11 vs. r = -0.09, P = 0.75). Metabolic control and cardiac function decline with age. The lack of relationship between glucose control and cardiac power may suggest that metabolic control does not influence cardiac function and performance in older women.

Evaluation of plaque characteristics in coronary artery patients with impaired glucose tolerance through optical coherence tomography

OBJECTIVE

With the adoption of optical coherence tomography (OCT), this study targets the impacts on plaque characteristics brought about by impaired glucose tolerance (IGT) in patients with coronary artery disease.

METHODS

For this study, 150 patients with coronary artery disease were recruited. Regarding glycosylated hemoglobin (HbAlc), the patients were sectioned into normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes mellitus (DM) groups. Coronary angiography (CAG) and OCT were conducted for 150 patients.

RESULTS

There were 186 plaques discovered in 150 patients (37, 40, 44, and 65 in the NGT, IFG, IGT, and DM groups, respectively). Compared to the NGT group, the lipid core size, which is presented as the average angle of the lipid arc, was markedly larger in the IFG,IGT and DM groups ( 135.7 ± 32.7 Ê, 161.2 ± 55.7 Ê, 162.5 ± 55.8 Ê, and 170.2 ± 59.7 Ê, respectively, all P values< 0.05). Meanwhile, the fibrous cap over the lipid core in the NGT group was remarkably thicker than that in the IFG, IGT, and DM groups (115.7 ± 47.7 μm vs. 77.7 ± 23.5 μm, 75.1 ± 23.2 µm, 71.2 ± 22.1 µm, all P values<0.05).

CONCLUSION

Coronary plaques in coronary artery patients with NDT are more stable than in those with IGT and DM.

Association of glycemic status and segmental left ventricular wall thickness in subjects without prior cardiovascular disease: a cross-sectional study

Background

Left ventricular (LV) hypertrophy and changes in LV geometry are associated with increased cardiovascular mortality. Subjects with type 2 diabetes have an increased risk of such alterations in cardiac morphology. We sought to assess the association of glycemic status and LV wall thickness measured by cardiac magnetic resonance (CMR), and potential interactions of hypertension and diabetes.

Methods

CMR was performed on 359 participants from a cross-sectional study nested in a population-based cohort (KORA FF4) free of overt cardiovascular disease. Participants were classified according to their glycemic status as either control (normal glucose metabolism), prediabetes or type 2 diabetes. Segmentation of the left ventricle was defined according to the American Heart Association (AHA) 16-segment model. Measurements of wall thickness were obtained at end-diastole and analyzed by linear regression models adjusted for traditional cardiovascular risk factors.

Results

LV wall thickness gradually increased from normoglycemic controls to subjects with prediabetes and subjects with diabetes (8.8 ± 1.4 vs 9.9 ± 1.4 vs 10.5 ± 1.6 mm, respectively). The association was independent of hypertension and traditional cardiovascular risk factors (β-coefficient: 0.44 mm for prediabetes and 0.70 mm for diabetes, p-values compared to controls: p = 0.007 and p = 0.004, respectively). Whereas the association of glycemic status was strongest for the mid-cavity segments, the association of hypertension was strongest for the basal segments.

Conclusion

Abnormal glucose metabolism, including pre-diabetes, is associated with increased LV wall thickness independent of hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0900-7) contains supplementary material, which is available to authorized users.

Dysfunctional HDL in diabetes mellitus and its role in the pathogenesis of cardiovascular disease

Coronary artery disease, the leading cause of death in the developed and developing countries, is prevalent in diabetes mellitus with 68% cardiovascular disease (CVD)-related mortality. Epidemiological studies suggested inverse correlation between HDL and CVD occurrence. Therefore, low HDL concentration observed in diabetic patients compared to non-diabetic individuals was thought to be one of the primary causes of increased risks of CVD. Efforts to raise HDL level via CETP inhibitors, Torcetrapib and Dalcetrapib, turned out to be disappointing in outcome studies despite substantial increases in HDL-C, suggesting that factors beyond HDL concentration may be responsible for the increased risks of CVD. Therefore, recent studies have focused more on HDL function than on HDL levels. The metabolic environment in diabetes mellitus condition such as hyperglycemia-induced advanced glycation end products, oxidative stress, and inflammation promote HDL dysfunction leading to greater risks of CVD. This review discusses dysfunctional HDL as one of the mechanisms of increased CVD risks in diabetes mellitus through adversely affecting components that support HDL function in cholesterol efflux and LDL oxidation. The dampening of reverse cholesterol transport, a key process that removes cholesterol from lipid-laden macrophages in the arterial wall, leads to increased risks of CVD in diabetic patients. Therapeutic approaches to keep diabetes under control may benefit patients from developing CVD.

Inhibition of IKKɛ and TBK1 Improves Glucose Control in a Subset of Patients with Type 2 Diabetes

Numerous studies indicate an inflammatory link between obesity and type 2 diabetes. The inflammatory kinases IKKɛ and TBK1 are elevated in obesity; their inhibition in obese mice reduces weight, insulin resistance, fatty liver and inflammation. Here we studied amlexanox, an inhibitor of IKKɛ and TBK1, in a proof-of-concept randomized, double-blind, placebo-controlled study of 42 obese patients with type 2 diabetes and nonalcoholic fatty liver disease. Treatment of patients with amlexanox produced a statistically significant reduction in Hemoglobin A1c and fructosamine. Interestingly, a subset of drug responders also exhibited improvements in insulin sensitivity and hepatic steatosis. This subgroup was characterized by a distinct inflammatory gene expression signature from biopsied subcutaneous fat at baseline. They also exhibited a unique pattern of gene expression changes in response to amlexanox, consistent with increased energy expenditure. Together, these data suggest that dual-specificity inhibitors of IKKɛ and TBK1 may be effective therapies for metabolic disease in an identifiable subset of patients.

Diabetes and impaired glucose metabolism is associated with more cold-related cardiorespiratory symptoms

AIMS

Diabetes and impaired glucose metabolism cause metabolic, neural and circulatory disturbances that may predispose to adverse cooling and related symptoms during the cold season. This study assessed the prevalence of cold-related cardiorespiratory symptoms in the general population according to glycaemic status.

METHODS

The study population consisted of 2436 men and 2708 women aged 45-74years who participated in the National FINRISK cold sub-studies in 2002 and 2007. A questionnaire assessed cold-related symptoms (respiratory, cardiac, peripheral circulation). Glycaemic status was determined based on fasting blood glucose, oral glucose tolerance tests or reported diagnosis of diabetes and categorized into normal glucose metabolism, impaired fasting blood glucose, impaired glucose tolerance, screening-detected type 2 diabetes and type 2 diabetes.

RESULTS

Type 2 diabetes was associated with increased odds for cold-related dyspnoea [Adjusted OR 1.72 (95% CI, 1.28-2.30)], chest pain [2.10 (1.32-3.34)] and respiratory symptoms [1.85 (1.44-2.38)] compared with normal glucose metabolism. Screened type 2 diabetes showed increased OR for cold-related dyspnoea [1.36 (1.04-1.77)], cough [1.41 (1.06-1.87)] and cardiac symptoms [1.51 (1.04-2.20)]. Worsening of glycaemic status was associated with increased odds for cold-related dyspnoea (from 1.16 in impaired fasting glucose to 1.72 in type 2 diabetes, P=0.000), cough (1.02-1.27, P=0.032), chest pain (1.28-2.10, P=0.006), arrhythmias (0.87-1.74, P=0.020), cardiac (1.11-1.99, P=0.000), respiratory (1.14-1.84, P=0.000) and all symptoms (1.05-1.66, P=0.003).

CONCLUSIONS

Subjects with diabetes and pre-diabetes experience more cold-related cardiorespiratory symptoms and need instructions for proper protection from cold weather to reduce adverse health effects.

Plaque Characteristics in Coronary Artery Disease Patients with Impaired Glucose Tolerance

BACKGROUND

Impaired glucose tolerance (IGT) patients are known to have a high risk of cardiovascular events and their prognosis has been reported to be poor. The present study aimed to compare coronary plaque characteristics among coronary artery disease (CAD) patients with normal glucose tolerance (NGT), those with IGT, and those with diabetes mellitus (DM) by using optical coherence tomography (OCT).

METHODS

The present study included 101 coronary artery disease patients (mean age, 67.9 ± 10.4 years; 82.4% male). OCT was performed for target and non-target vessels during percutaneous coronary intervention. The patients were divided into the following 3 groups: the NGT, IGT, and DM groups.

RESULTS

A total of 136 non-target residual plaques were found in 101 patients (27, 30, and 44 in the NGT, IGT, and DM groups, respectively). The size of the lipid core expressed as the mean angle of the lipid arc was significantly greater in the IGT and DM groups than in the NGT group (163.0 ± 58.7°, 170.1 ± 59.3°, and 130.9 ± 37.7°, respectively, P < 0.05). The fibrous cap covering the lipid core was significantly thinner in the IGT group than in the NGT group (77.0 ± 23.4 μm vs. 105.6 ± 47.0 μm, P = 0.040).

CONCLUSION

The coronary plaques in CAD patients are more vulnerable when having IGT compared to those with NGT, and similar to those with DM. This finding may explain the high risk of cardiovascular events in CAD patients with IGT.

Inverse association of total testosterone with central haemodynamics and left ventricular mass in hypertensive men

BACKGROUND

There is evidence for inverse association between endogenous testosterone and blood pressure. Furthermore, low plasma testosterone is associated with increased risk of major cardiovascular events in middle-aged hypertensive men. Central (aortic) blood pressures determine left ventricular hypertrophy and predict cardiovascular mortality. The aim of the present study was to assess the relationship of total testosterone (TT) with central haemodynamics and left ventricular mass in hypertensive men.

METHODS

We investigated 134 non-diabetic, middle-aged, hypertensive men and 60 age-matched normotensive males. All participants were subject to measurement of aortic systolic (aoSBP) and pulse pressure (aoPP) by pulse wave analysis using the SphygmoCor device. Wave reflections were assessed by the measurement of heart rate corrected augmentation index (AIx75). Echocardiography was performed in all individuals and left ventricular mass (LVM) was calculated using the Devereux's formula. Plasma TT was measured by enzyme immunoassay.

RESULTS

In hypertensive men, univariate analysis showed an inverse, significant correlation between TT and aoSBP (r = -20, p = 0.02), aoPP (r = -0.21, p = 0.01), AIx75 (r = -0.22, p = 0.01) and LVM (r = -0.19, p = 0.008). Multivariate regression analysis demonstrated an independent inverse association of TT with aoPP (b = -0.21, p = 0.02), AIx75 (b = -0.19, p = 0.03) and LVM (b = -0.28, p = 0.005) after adjustment for age, BMI, smoking, total cholesterol, triglycerides, fasting glucose, mean arterial pressure, antihypertensive treatment and statin use. Independent associations were retained even after inclusion of normotensive subjects in the analysis.

CONCLUSIONS

In hypertensive men, TT is independently and inversely associated with central pulse pressure, wave reflections and left ventricular mass. Considering the adverse prognostic role of central blood pressures and LV hypertrophy on cardiovascular outcomes in hypertensive patients, the present findings might explain part of the increased cardiovascular risk associated with low testosterone. Whether measurement of central haemodynamics may improve risk stratification in hypertensive men with low testosterone warrants further investigation.

ACE2 Deficiency Worsens Epicardial Adipose Tissue Inflammation and Cardiac Dysfunction in Response to Diet-Induced Obesity

Obesity is increasing in prevalence and is strongly associated with metabolic and cardiovascular disorders. The renin-angiotensin system (RAS) has emerged as a key pathogenic mechanism for these disorders; angiotensin (Ang)-converting enzyme 2 (ACE2) negatively regulates RAS by metabolizing Ang II into Ang 1-7. We studied the role of ACE2 in obesity-mediated cardiac dysfunction. ACE2 null (ACE2KO) and wild-type (WT) mice were fed a high-fat diet (HFD) or a control diet and studied at 6 months of age. Loss of ACE2 resulted in decreased weight gain but increased glucose intolerance, epicardial adipose tissue (EAT) inflammation, and polarization of macrophages into a proinflammatory phenotype in response to HFD. Similarly, human EAT in patients with obesity and heart failure displayed a proinflammatory macrophage phenotype. Exacerbated EAT inflammation in ACE2KO-HFD mice was associated with decreased myocardial adiponectin, decreased phosphorylation of AMPK, increased cardiac steatosis and lipotoxicity, and myocardial insulin resistance, which worsened heart function. Ang 1-7 (24 µg/kg/h) administered to ACE2KO-HFD mice resulted in ameliorated EAT inflammation and reduced cardiac steatosis and lipotoxicity, resulting in normalization of heart failure. In conclusion, ACE2 plays a novel role in heart disease associated with obesity wherein ACE2 negatively regulates obesity-induced EAT inflammation and cardiac insulin resistance.

Impaired fasting glucose and left ventricular diastolic dysfunction in middle-age adults: a retrospective cross-sectional analysis of 2971 subjects

BACKGROUND

Left ventricular (LV) diastolic dysfunction (LVDD) is a well-established and early echocardiographic characteristic of diabetic cardiomyopathy. However, there are limited data on the association between impaired fasting glucose (IFG) and LVDD.

OBJECTIVE

To determine whether IFG is associated with LVDD among middle age adults.

METHODS

Amongst 3781 subjects screened in an annual health survey program and referred for an echocardiogram, 2971 individuals without LV systolic dysfunction or valvular heart disease were selected. Mean age of study population was 59 ± 12 years and 75% were men. The subjects were categorized into three groups: euglycemia (N = 2025), IFG (N = 534) and diabetes mellitus (DM; N = 412). Doppler echocardiography readers were blinded to glycemic state. Subjects with impaired LV relaxation, pseudo-normal or restrictive filling patterns were defined as having LVDD.

RESULTS

LVDD was diagnosed in 574 (19 %) of subjects and it was more prevalent among patients with IFG and DM than in euglycemic individuals (27, 30 and 15%, respectively; p < 0.001). Patients with IFG and DM had lower ratios of early (E) to late (A) trans-mitral flow (0.9 ± 0.3 and 0.9 ± 0.3 vs. 1.1 ± 0.4, respectively, p < 0.001). LV hypertrophy (LVH) was also more prevalent among patients with IFG and DM (11 and 18%, respectively, vs. 9%; p < 0.001). Multivariate binary logistic regression model adjusted to age, gender, obesity, LVH, renal function, total, high and low density lipoprotein cholesterol, triglycerides, ischemic heart disease, hypertension and LV ejection fraction showed that patients with IFG were 43% more likely to have LVDD compared with euglycemic subjects (95% confidence interval 1.12-1.83, p = 0.004).

CONCLUSIONS

IFG is independently associated with a significant increase in the likelihood for the presence of LVDD in middle aged adults.

Periodontal infection, impaired fasting glucose and impaired glucose tolerance: results from the Continuous National Health and Nutrition Examination Survey 2009-2010

AIM

We investigated the relationship between periodontal disease, a clinical manifestation of periodontal infection, and pre-diabetes.

METHODS

The National Health and Nutrition Examination Survey, 2009-2010 enrolled 1165 diabetes-free adults (51% female) aged 30-80 years (mean ± SD=50 ± 14) who received a full-mouth periodontal examination and an oral glucose tolerance test. Participants were classified as having none/mild, moderate or severe periodontitis and also according to mean probing depth ≥ 2.19 mm or attachment loss ≥ 1.78 mm, (respective 75th percentiles). Pre-diabetes was defined according to ADA criteria as either: (i) impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). In multivariable logistic regression models, the odds of IFG and IGT were regressed on levels of periodontitis category.

RESULTS

The odds ratios and 95% confidence intervals for having IGT among participants with moderate or severe periodontitis, relative to participants with none/mild periodontitis were 1.07 [0.50, 2.25] and 1.93 [1.18, 3.17], p = 0.02. The ORs for having IFG were 1.14 [0.74, 1.77] and 1.12 [0.58, 2.18], p = 0.84. PD ≥ 75 th percentile was related to a 105% increase in the odds of IGT: OR [95% CI] = 2.05 [1.24, 3.39], p = 0.005.

CONCLUSIONS

Periodontal infection was positively associated with prevalent impaired glucose tolerance in a cross-sectional study among a nationally representative sample.

Cardiometabolic risk in overweight subjects with or without relative fat-free mass deficiency: the Strong Heart Study

BACKGROUND AND AIM

Sarcopenia is a condition mainly due to loss of fat-free mass (FFM) in elderly individuals. RFFMD, however, is also frequent in obese subjects due to abnormal body composition. Objective of this study was to evaluate the impact of relative fat-free mass deficiency (RFFMD) on cardiometabolic (CM) risk in obese normoglycemic individuals.

METHODS AND RESULTS

Overweight/obese American Indians from the Strong Heart Study population, without diabetes and with FBG ≤ 110 mg/dL and with GFR >60 mg/mL/1.73 m(2) were selected for this analysis (n = 742). RFFMD was defined on the basis of a multivariable equation previously reported. Fasting glucose and 2 h-OGTT were measured together with urine albumin/creatinine excretion, laboratory and anthropometric parameters. In addition to lower FFM and greater adipose mass, participants with RFFMD had higher body mass index, waist circumference, C-reactive protein, fibrinogen, insulin resistance and urinary albumin/creatinine than participants with normal FFM (all p < 0.001); they also had a greater prevalence of hypertension, impaired glucose tolerance (IGT) or OGTT-diabetes than participants with normal FFM (all p < 0.003) and a near 2-fold greater probability of significant proteinuria (p < 0.01). RFFMD was more frequent in women than in men: significant sex-RFFMD interactions were found for BMI and waist circumference (both p < 0.0001).

CONCLUSIONS

RFFMD in overweight/obese normoglycemic individuals is associated with greater probability of hypertension, abnormalities of glucose tolerance and proteinuria. Assessment of RFFRMD might, therefore, help stratifying cardiometabolic risk among normoglycemic individuals with overweight/obesity.

Early impairment of contractility reserve in patients with insulin resistance in comparison with healthy subjects

Background

Insulin resistance (IR) is currently considered a crucial cardiovascular (CV) risk factor, which seems to play a dominant role in the evolution toward cardiac and vascular impairment. Early IR-induced cardiac dysfunction can be assessed by Doppler-derived myocardial systolic strain rate (SR) index, measured at baseline and after dobutamine stress echocardiography (DSE).

Methods

Thirty IR patients (HOMA-IR = 7 ± 5.2, age 52.6 ± 2.1 years), and 20 healthy, age and sex matched controls were studied. IR had been diagnosed in all patients in the 3 months preceding the study. Dobutamine echocardiography was performed in all subjects to exclude ischemic heart disease, and left ventricular contractile reserve (LVCR) was then assessed. LVCR was evaluated as an increase in the peak of an average longitudinal SR, measured in the basal and mid segments of 2 and 4 chamber ventricular walls.

Results

No significant differences between the 2 groups were revealed by baseline echocardiography. In contrast, after DSE a significant decrease of Delta SR was found in the IR group in comparison to the controls (0.54 ± 0.31 s⁻¹vs 1.14 ± 0.45 s⁻¹; p < 0.0001).

Conclusions

Our results show that IR, even if isolated and arising within a short time period, not only represents the initial phase of future diabetes, but may adversely affect heart function, as evidenced by the depressed LVCR. Our data strengthen the need for attention to be paid to IR state and for an early therapeutic approach.