Impaired glucose tolerance and insulin resistance in heart failure: underrecognized and undertreated?

Association between Hemoglobin Glycation Index and In-Hospital all-cause mortality of patients with Congestive Heart Failure: a retrospective study utilizing the MIMIC-IV database

Background

The aim of this study was to explore the relationship between the hemoglobin glycation index (HGI) of Congestive Heart Failure (CHF) patients and their risk of mortality within 365 days.

Patients and methods

The Medical Information Mart for Intensive Care (MIMIC-IV) database supplied the patient data for this study, which was categorized into quartiles based on the HGI. The primary endpoint was all-cause mortality within a 365-day period. Kaplan-Meier (K-M) analysis was utilized to compare this primary endpoint across the four aforementioned groups. The relationship between the HGI and the endpoint was examined using restricted cubic splines (RCS) and a Cox proportional hazards analysis.

Results

A total of 985 patients were included in this study. HGI was significantly associated with 30 days mortality (15.9%; HR, 0.79; 95% CI, (0.67~0.92); P=0.003) and 60 days mortality (19.3%; HR, 0.83; 95% CI, (0.72~0.96); P=0.011) and 90 days mortality (22.1%; HR, 0.86; 95% CI, (0.75~0.99); P=0.031) and 365 days mortality (30.7%; HR, 0.97; 95% CI, (0.86~1.09); P=0.611) in patients with critical CHF in the completely adjusted Cox proportional risk model. RCS analysis revealed a U-shaped relationship between HGI and outcome events. KM curves survival analysis suggests a correlation between 30 days and 365 days mortality in HGI and CHF patients.

Conclusions

A higher HGI has a more protective effect than a low HGI for patients with CHF and was directly associated with short-term mortality rates. These findings may be helpful in the management of patients with CHF.

Impact of diabetes mellitus on mortality in pulmonary hypertension: A systematic review and meta-analysis

BACKGROUND

Pulmonary hypertension (PH) is a progressive disease characterized by endothelial dysfunction and vascular remodeling and is a leading cause of mortality worldwide. Although it is independently associated with multiple comorbidities, the impact of diabetes mellitus (DM) on mortality in patients with PH remains uncertain. To address this issue, we conducted a systematic review and meta-analysis to investigate the effect of DM on survival in patients with pulmonary hypertension.

AIM

To investigate the impact of diabetes mellitus on mortality in pulmonary hypertension patients.

METHODS

We conducted a comprehensive search of four major electronic bibliographic databases like PubMed, Google Scholar, Scopus, and Embase, and identified 106 relevant studies, out of 1561 articles, published since the year 2000 for full-text review. Fourteen retrospective and prospective cohort studies that compared survival between patients with DM and those without DM in the context of PH were deemed eligible for inclusion in our meta-analysis. The study was registered on PROSPERO with the identifier CRD42023390232.

RESULTS

A total of 116455 patients with PH were included in the meta-analysis, of whom 41228 suffered from DM and 75227 did not. The results of our meta-analysis indicate an elevated mortality rate among PH patients with diabetes mellitus in comparison to those without DM [odds ratio (OR) = 1.40, 95%CI: 1.15-1.70, P = 0.0006]. The meta-regression analysis unveiled a statistically significant negative association between mean age and effect size (coefficient = -0.036, P value = 0.018). Conversely, a statistically significant positive association was detected between female proportion and effect size (coefficient = 0.000, P value < 0.001).

CONCLUSION

Our meta-analysis, which included approximately 116500 PH patients, revealed that the presence of diabetes mellitus was associated with increased odds of mortality when compared to non-diabetic patients. The meta-regression analysis indicates that studies with older participants and lower proportions of females tend to exhibit smaller effect sizes. Clinically, these findings underscore the importance of incorporating diabetes status into the risk stratification of patients with PH with more aggressive monitoring and early intervention to improve prognosis potentially.

Associations between non-insulin-based insulin resistance indices and heart failure prevalence in overweight/obesity adults without diabetes mellitus: evidence from the NHANES 2001-2018

BACKGROUND

The triglyceride glucose (TyG) index and triglyceride-to-high-density lipoprotein cholesterol (TG/HDL-C) ratio are recognized as simple non-insulin-based insulin resistance indices. Our study aimed to explore the relationship between these two indicators and heart failure (HF) in overweight or obesity individuals without diabetes.

METHODS

This cross-sectional study selected 13,473 participants from the National Health and Nutrition Examination Survey (NHANES) 2001-2018 dataset. Weighted multivariable logistic regression and subgroup analysis were employed to evaluate the relationships between TyG index, TG/HDL-C ratio, and HF prevalence, respectively. Additionally, smooth curve fitting was utilized to analyze the dose-response relationships.

RESULTS

A total of 13,473 obesity or overweight people without diabetes were included in this study through screening, among whom 291 (2.16%) had comorbid HF. The results of multivariable logistic regression suggested that the highest TyG index (OR = 2.4, 95% CI = 1.4-4.2, p = 0.002) and the highest TG/HDL-C ratio (OR = 1.2, 95% CI = 1.1-1.3, p < 0.001) both increased the prevalence of HF, especially in the non-Hispanic population. Dose-response relationships suggested nonlinear relationships between these two indicators and HF.

CONCLUSION

Our study demonstrated that elevated TyG index and TG/HDL-C ratio were closely associated with the prevalence of HF, and both exhibited nonlinear relationships with HF prevalence in overweight/obesity adults without diabetes. Based on these findings, additional prospective studies are needed for further validation.

Association between triglyceride glucose-body mass and one-year all-cause mortality of patients with heart failure: a retrospective study utilizing the MIMIC-IV database

BACKGROUND

The triglyceride glucose-body mass (TyG-BMI) index is acknowledged as both a reliable indicator of the risk of cardiovascular disease and an accurate surrogate biomarker for evaluating insulin resistance (IR). The importance of the TyG-BMI index among people with heart failure (HF), however, requires more investigation. The objective of this study was to inquire about the relationship between HF patients' TyG-BMI index and their risk of 360-day mortality.

METHODS

The Medical Information Mart for Intensive Care (MIMIC-IV) database provided the study's patient data, which were divided into quartiles according to their TyG-BMI index. The endpoint was mortality from all causes within 360 days. Kaplan-Meier analysis was used to compare this primary endpoint amongst the four groups indicated above. The association between the TyG-BMI index and the endpoint was investigated using restricted cubic splines and Cox proportional hazards analysis.

RESULTS

The study enrolled a total of 423 patients with HF (59.2% male), of whom 70 patients (16.9%) died within 360 days. Patients with higher TyG-BMI indexes had significantly lower mortality risks, according to the Kaplan-Meier analysis (log-rank P = 0.003). Furthermore, the restricted cubic spline analysis illustrated a decrease in the risk of all-cause mortality with an increasing TyG-BMI index. Additionally, multivariable Cox proportional hazards analyses showed that the risk of 360-day death from all causes was considerably higher in the lowest quartile of TyG-BMI. In comparison to the lowest TyG-BMI group, the fully adjusted Cox model yielded a hazard ratio (HR) of 0.24 (95% CI: 0.10, 0.59; p = 0.002) for 360-day mortality.

CONCLUSIONS

In patients diagnosed with HF, a lower TyG-BMI index is strongly related to a higher risk of 360-day mortality. This index can be employed to categorize the risk levels of patients with HF and predict their one-year all-cause mortality .

Insulin Resistance Is Associated With Heart Failure With Recovered Ejection Fraction in Patients Without Diabetes

Background Because of advances in medical treatments, a substantial proportion of patients with heart failure (HF) have experienced recovery of ejection fraction (EF), termed HF with recovered EF (HFrecEF). Insulin resistance (IR) is prevalent in HF and tightly related with prognosis. This study investigates the relationship between IR and the incidence of HFrecEF in patients who are nondiabetic. Methods and Results A total of 262 patients with HF with reduced EF (HFrEF) who were nondiabetic were consecutively enrolled. Patients were classified into HFrecEF (follow-up EF>40% and ≥10% absolute increase) or otherwise persistent HFrEF based on repeat echocardiograms after 12 months. IR was estimated by an updated homeostasis model assessment for IR (HOMA2-IR). The median HOMA2-IR level was 1.05 (interquartile range [IQR], 0.67-1.63) in our cohort of patients with HF who were nondiabetic. During follow-up, 121 (odds ratio [OR], 46.2% [95% CI 40.2-52.2]) patients developed HFrecEF. Compared with patients with HFrEF, patients with HFrecEF had significantly lower HOMA2-IR levels (0.92 [IQR, 0.61-1.37] versus 1.14 [IQR, 0.75-1.78], P=0.007), especially in nonischemic HF. Log₂-transformed HOMA2-IR was inversely correlated to improvements in EF (Pearson's r=-0.25, P<0.001). After multivariable adjustment, a doubling of HOMA2-IR was associated with a 42.8% decreased likelihood of HFrecEF (OR, 0.572 [95% CI, 0.385-0.827]). Conclusions This study reveals that IR is independently associated with compromised development of HFrecEF in patients who are nondiabetic.

Systems Pharmacology-Based Strategy to Investigate Pharmacological Mechanisms of Total Flavonoids in Dracocephalum moldavica on Chronic Heart Failure

Heart failure (HF) is a clinical syndrome of cardiac insufficiency caused by abnormalities in cardiac structure and function that arise for various reasons, and it is the final stage of most cardiovascular diseases’ progression. Total flavonoid extract from Dracocephalum moldavica L. (TFDM) has many pharmacological and biological roles, such as cardioprotective, neuroprotective, anti-atherogenic, antihypertensive, anti-diabetic, anti-inflammatory, antioxidant, etc. However, its effect on HF and its molecular mechanism are still unclear. In this study, we used systems pharmacology and an animal model of HF to investigate the cardioprotective effect of TFDM and its molecular mechanism. Eleven compounds in TFDM were obtained from the literature, and 114 overlapping genes related to TFDM and HF were collected from several databases. A PPI network and C-T network were established, and GO enrichment analysis and KEGG pathway analysis were performed. The top targets from the PPI network and C-T network were validated using molecular docking. The pharmacological activity was investigated in an HFpEF (heart failure with preserved ejection fraction) mouse model. This study shows that TFDM has a protective effect on HFpEF, and its protective mechanism may be related to the regulation of proinflammatory cytokines, apoptosis-related genes, fibrosis-related genes, etc. Collectively, this study offers new insights for researchers to understand the protective effect and mechanism of TFDM against HFpEF using a network pharmacology method and a murine model of HFpEF, which suggest that TFDM is a promising therapy for HFpEF in the clinic.

Friedreich's Ataxia related Diabetes: Epidemiology and management practices

AIMS

Friedreich's Ataxia (FRDA) is a progressive neuromuscular disorder typically caused by GAA triplet repeat expansions in both frataxin gene alleles. FRDA can be complicated by diabetes mellitus (DM). The objective of this study was to describe the prevalence of, risk factors for, and management practices of FRDA-related DM.

METHODS

FACOMS, a prospective, multi-site natural history study, includes 1,104 individuals. Extracted data included the presence of DM and other co-morbidities, genetic diagnosis, and markers of disease severity. We performed detailed medical record review and a survey for the subset of individuals with FRDA-related DM followed at one FACOMS site, Children's Hospital of Philadelphia.

RESULTS

FRDA-related DM was reported by 8.7% of individuals. Age, severe disease, and FRDA cardiac complications were positively associated with DM risk. FRDA-related DM was generally well-controlled, as reflected by HbA1c, though diabetic ketoacidosis did occur. Insulin is the mainstay of treatment (64-74% overall); in adults, metformin use was common and newer glucose-lowering agents were used rarely.

CONCLUSIONS

Clinical factors identify individuals at increased risk for FRDA-related DM. Future studies should test strategies for FRDA-related DM screening and management, in particular the potential role for novel glucose-lowering therapies in preventing or delaying FRDA-related cardiac disease.

Prediabetes and the risk of heart failure: A meta-analysis

AIM

To determine the role of prediabetes in the incidence of heart failure (HF).

MATERIALS AND METHODS

We searched electronic databases (PubMed, Embase, Google Scholar and OpenGrey) for studies up to 31 December 2020. Studies were included for meta-analysis if they reported adjusted relative risks (RRs) and 95% confidence intervals (CIs) for the risk of HF for prediabetes compared with normoglycaemia. Prediabetes was defined as impaired fasting glucose (IFG) according to the World Health Organization (WHO) criteria (IFG-WHO), or according to the American Diabetes Association (ADA) definition (IFG-ADA), impaired glucose tolerance (IGT), raised HbA1c according to the ADA criteria (HbA1c-ADA), or according to the International Expert Committee (IEC) recommendation (HbA1c-IEC).

RESULTS

A total of 15 studies comprising 9,827,430 individuals provided data for this analysis. The median follow-up duration of the included studies was 8.0 years. Compared with normoglycaemia, prediabetes was associated with an increased risk for HF: IFG-ADA (RR: 1.09, 95% CI: 1.05-1.13), IFG-WHO (RR: 1.18, 95% CI: 1.07-1.30), IGT (RR 1.58, 95% CI 1.04-2.39), HbA1c-ADA (RR 1.28, 95% CI 1.16-1.41) or HbA1c-IEC (RR 1.40, 95% CI 1.09-1.79), respectively.

CONCLUSIONS

Prediabetes is associated with an increased risk of HF. Future studies are needed to evaluate effective treatments for prediabetes to prevent the development and progression of HF.

Impact of peroxisome proliferator-activated receptor-α on diabetic cardiomyopathy

The prevalence of cardiomyopathy is higher in diabetic patients than those without diabetes. Diabetic cardiomyopathy (DCM) is defined as a clinical condition of abnormal myocardial structure and performance in diabetic patients without other cardiac risk factors, such as coronary artery disease, hypertension, and significant valvular disease. Multiple molecular events contribute to the development of DCM, which include the alterations in energy metabolism (fatty acid, glucose, ketone and branched chain amino acids) and the abnormalities of subcellular components in the heart, such as impaired insulin signaling, increased oxidative stress, calcium mishandling and inflammation. There are no specific drugs in treating DCM despite of decades of basic and clinical investigations. This is, in part, due to the lack of our understanding as to how heart failure initiates and develops, especially in diabetic patients without an underlying ischemic cause. Some of the traditional anti-diabetic or lipid-lowering agents aimed at shifting the balance of cardiac metabolism from utilizing fat to glucose have been shown inadequately targeting multiple aspects of the conditions. Peroxisome proliferator-activated receptor α (PPARα), a transcription factor, plays an important role in mediating DCM-related molecular events. Pharmacological targeting of PPARα activation has been demonstrated to be one of the important strategies for patients with diabetes, metabolic syndrome, and atherosclerotic cardiovascular diseases. The aim of this review is to provide a contemporary view of PPARα in association with the underlying pathophysiological changes in DCM. We discuss the PPARα-related drugs in clinical applications and facts related to the drugs that may be considered as risky (such as fenofibrate, bezafibrate, clofibrate) or safe (pemafibrate, metformin and glucagon-like peptide 1-receptor agonists) or having the potential (sodium-glucose co-transporter 2 inhibitor) in treating DCM.

Diabetic Cardiomyopathy: From Mechanism to Management in a Nutshell

Diabetic cardiomyopathy (DCM) is a significant complication of diabetes mellitus characterized by gradually failing heart with detrimental cardiac remodelings, such as fibrosis and diastolic and systolic dysfunction, which is not directly attributable to coronary artery disease. Insulin resistance and resulting hyperglycemia is the main trigger involved in the initiation of diabetic cardiomyopathy. There is a constellation of many pathophysiological events, such as lipotoxicity, oxidative stress, inflammation, inappropriate activation of the renin-angiotensin-aldosterone system, dysfunctional immune modulation promoting increased rate of cardiac cell injury, apoptosis, and necrosis, which ultimately culminates into interstitial fibrosis, cardiac stiffness, diastolic dysfunction, initially, and later systolic dysfunction too. These events finally lead to clinical heart failure of DCM. Herein, The pathophysiology of DCM is briefly discussed. Furthermore, potential therapeutic strategies currently used for DCM are also briefly mentioned.

Glucocorticoid exposure causes disrupted glucoregulation, cardiac inflammation and elevated dipeptidyl peptidase-4 activity independent of glycogen synthase kinase-3 in female rats

Objective: We tested the hypothesis that glucocorticoid (GC) exposure in female rats would lead to glucose dysregulation and elevated cardiac inflammatory biomarkers, which are dipeptidyl peptidase-4 (DPP-4)- and glycogen synthase kinase-3 (GSK-3)-dependent. Methods: Female Wistar rats received vehicle (control; n = 6) or GC (dexamethasone; n = 6; 0.2 mg/kg; p.o.) for six days. Insulin resistance was determined by HOMA-IR. DPP-4 activity was determined by fluorescence method, whereas vascular cell adhesion molecule-1 (VCAM-1), uric acid, malondialdehyde (MDA), lactate dehydrogenase (LDH) and nitric oxide (NO) from plasma and cardiac homogenate were estimated as cardiac pro-inflammatory biomarkers. Results: Results showed that GC exposure resulted in glucose dysregulation and increased plasma and cardiac pro-inflammatory markers which are associated with elevated DPP-4 activity but reduced GSK-3. Conclusions: The present results demonstrate that GC exposure would cause glucose dysregulation, increased DPP-4 activity and cardiac inflammation that is independent of GSK-3.

Treatment of Heart Failure with Sodium-Glucose Cotransporter 2 Inhibitors and Other Anti-diabetic Drugs

Patients with type 2 diabetes are at increased risk of developing heart failure, cardiovascular death and renal failure. The recent results of three large sodium-glucose cotransporter 2 inhibitor cardiovascular outcomes trials have demonstrated a reduction in heart failure hospitalisation and progressive renal failure. One trial also showed a fall in cardiovascular and total death. A broad spectrum of patients with diabetes benefit from these salutary effects in cardiac and renal function and so these trials have important implications for the management of patients with type 2 diabetes. Selected glucagon-like peptide 1 receptor agonists have also been shown to reduce adverse cardiovascular outcomes.

Diabetic cardiomyopathy: where we are and where we are going

The global burden of diabetes mellitus and its related complications are currently increasing. Diabetes mellitus affects the heart through various mechanisms including microvascular impairment, metabolic disturbance, subcellular component abnormalities, cardiac autonomic dysfunction, and a maladaptive immune response. Eventually, diabetes mellitus can cause functional and structural changes in the myocardium without coronary artery disease, a disorder known as diabetic cardiomyopathy (DCM). There are many diagnostic tools and management options for DCM, although it is difficult to detect its development and effectively prevent its progression. In this review, we summarize the current research regarding the pathophysiology and pathogenesis of DCM. Moreover, we discuss emerging diagnostic evaluation methods and treatment strategies for DCM, which may help our understanding of its underlying mechanisms and facilitate the identification of possible new therapeutic targets.

Cardiometabolic Syndrome and Increased Risk of Heart Failure

Approximately 50 % of patients with heart failure have diastolic heart failure (HFPEF) with the major predisposing risk factors age, inactivity, obesity, insulin resistance (IR), type-2 diabetes, and hypertension. The prognosis of HFPEF is comparable to that of systolic heart failure, but without any specific or effective treatment. This review presents a biomathematically corrected diagnostic approach for quantification of diastolic dysfunction (DD) via the age dependency of diastolic function. Pathophysiological mechanisms for DD in the cardiometabolic syndrome (CMS) are mainly based on downstream effects of IR including insufficient myocardial energy supply. The second section discusses therapeutic strategies for the control and therapy of CMS, IR, and the associated DD/HFPEF with a focus on dietary therapy that is independent of weight loss but improves all manifestations of the CMS and reduces cardiovascular risk.

Clinical effects of carvedilol and trimetazidine for the treatmentof alcoholic myocardiopathy

The aim of the study was to compare the clinical effects of carvedilol and trimetazidine for the treatment of alcoholic cardiomyopathy. A total of 60 patients diagnosed with alcoholic cardiomyopathy were enrolled in the study. The patients were randomly divided into the carvedilol (n=20), trimetazidine (n=20) and control (n=20) groups. The patients in the control, carvedilol and trimetazidine groups were treated with conventional drugs, conventional drugs + carvedil and conventional drugs + trimetazidine respectively, for 12 weeks. The patients were compared for their heart functions [left ventricular ejection fraction (LVEF), C-reactive protein (CRP) and 6 min walking], heart rate, blood pressure and heart enlargement (cardiothoracic proportion and left ventricular diameter) before and after treatment. The parameters studied for heart functions, heart rate, blood pressure, heart enlargement, clinical effects before and after treatment were statistically insignificant (p>0.05). After treatment, the carvedilol and trimetazidine groups showed higher LVEF and CRP, longer walking distance in 6 min, as well as lower heart rate and blood pressure (both systolic and diastolic) compared to the control group. Similarly, the cardiothoracic proportion and left ventricular internal diameter for the carvedilol and trimetazidine groups was lower than those of the control group, with better clinical effects (p<0.05). In conclusion, the curative effects of the carvedilol and trimetazidine groups of alcoholic myocardiopathy similar. Both are safe agents that may improve the cardiac function and heart expansion of patients.

Insulin resistance and hyperinsulinaemia in diabetic cardiomyopathy

Insulin resistance, type 2 diabetes mellitus and associated hyperinsulinaemia can promote the development of a specific form of cardiomyopathy that is independent of coronary artery disease and hypertension. Termed diabetic cardiomyopathy, this form of cardiomyopathy is a major cause of morbidity and mortality in developed nations, and the prevalence of this condition is rising in parallel with increases in the incidence of obesity and type 2 diabetes mellitus. Of note, female patients seem to be particularly susceptible to the development of this complication of metabolic disease. The diabetic cardiomyopathy observed in insulin- resistant or hyperinsulinaemic states is characterized by impaired myocardial insulin signalling, mitochondrial dysfunction, endoplasmic reticulum stress, impaired calcium homeostasis, abnormal coronary microcirculation, activation of the sympathetic nervous system, activation of the renin-angiotensin-aldosterone system and maladaptive immune responses. These pathophysiological changes result in oxidative stress, fibrosis, hypertrophy, cardiac diastolic dysfunction and eventually systolic heart failure. This Review highlights a surge in diabetic cardiomyopathy research, summarizes current understanding of the molecular mechanisms underpinning this condition and explores potential preventive and therapeutic strategies.

Amino acids and derivatives, a new treatment of chronic heart failure?

Amino acids play a key role in multiple cellular processes. Amino acids availability is reduced in patients with heart failure (HF) with deleterious consequences on cardiac and whole-body metabolism. Several metabolic abnormalities have been identified in the failing heart, and many of them lead to an increased need of amino acids. Recently, several clinical trials have been conducted to demonstrate the benefits of amino acids supplementation in patients with HF. Although they have shown an improvement of exercise tolerance and, in some cases, of left ventricular function, they have many limitations, namely small sample size, differences in patients' characteristics and nutritional supplementations, and lack of data regarding outcomes. Moreover recent data suggest that a multi-nutritional approach, including also antioxidants, vitamins, and metals, may be more effective. Larger trials are needed to ascertain safety, efficacy, and impact on prognosis of such an approach in HF.

Impact of left ventricular assist device on diabetes management: an evaluation through case analysis and clinical impact

BACKGROUND

Diabetes is a major risk factor for the development of heart failure (HF). In patients with advanced HF, left ventricular assist devices (LVADs) are increasingly used as a bridge to heart transplantation and destination therapy. It has been our observation that, post-LVAD implantation, diabetes management improves dramatically.

OBJECTIVE

We evaluated insulin requirements in a group of type 2 diabetes patients after LVAD implantation, compared them to a small control group, and performed a pertinent literature review.

METHODS

Relevant clinical and biochemical data were collected by chart review of 11 patients with known type 2 diabetes mellitus and HF who underwent LVAD implantation. Patients treated only with insulin were evaluated and compared with 5 control patients undergoing other cardiac procedures.

RESULTS

Insulin requirement decreased by 73% at 6 months from the pre-LVAD dose despite no significant changes in weight or glomerular filtration rate. Mean hemoglobin A1c reduced post-LVAD to 6.4% from 8.6%. Patients undergoing other cardiac procedures showed no significant changes in hemoglobin A1c or insulin requirements.

CONCLUSION

Patients with diabetes undergoing LVAD implantation demonstrated a significant reduction in insulin requirements. This finding underscores the importance of HF in the progression of insulin resistance.

Mandatory oral glucose tolerance tests identify more diabetics in stable patients with chronic heart failure: a prospective observational study

BACKGROUND

Many patients with chronic heart failure (CHF) are believed to have unrecognized diabetes, which is associated with a worse prognosis. This study aimed to describe glucose tolerance in a general stable CHF population and to identify determinants of glucose tolerance focusing on body composition and skeletal muscle strength.

METHODS

A prospective observational study was set up. Inclusion criteria were diagnosis of CHF, stable condition and absence of glucose-lowering medication. Patients underwent a 2 h oral glucose tolerance test (OGTT), isometric strength testing of the upper leg and dual energy x-ray absorptiometry. Health-related quality of life and physical activity level were assessed by questionnaire.

RESULTS

Data of 56 participants were analyzed. Despite near-normal fasting glucose values, 55% was classified as prediabetic, 14% as diabetic, and 20% as normal glucose tolerant. Of all newly diagnosed diabetic patients, 79% were diagnosed because of 2 h glucose values only and none because of HbA1c. Univariate mixed model analysis revealed ischaemic aetiology, daily physical activity, E/E', fat trunk/fat limbs and extension strength as possible explanatory variables for the glucose curve during the glucose tolerance test. When combined in one model, only fat trunk/fat limbs and E/E' remained significant predictors. Furthermore, fasting insulin was correlated with fat mass/height2 (r = 0.51, p < 0.0001), extension strength (r = -0.33, p < 0.01) and triglycerides (r = 0.39, p < 0.01).

CONCLUSIONS

Our data confirm that a large majority of CHF patients have impaired glucose tolerance. This glucose intolerance is related to fat distribution and left ventricular end-diastolic pressure.

Association between serum adipocyte fatty-acid binding protein concentrations, left ventricular function and myocardial perfusion abnormalities in patients with coronary artery disease

BACKGROUND

Adipokines, including adipocyte fatty acid-binding protein (A-FABP), have been demonstrated to be involved in the pathogenesis of atherosclerosis. In the present study, we investigated the association of circulating A-FABP level with severity of myocardial perfusion abnormalities analyzed by Tl-201 dipyridamole single-photon emission computed tomography.

METHODS

A total of 170 patients with coronary artery disease (CAD) from cardiovascular clinics were enrolled in the study. Serum A-FABP levels, echocardiography, and stress myocardial perfusion imaging results were analyzed.

RESULTS

Compared with the patients with mild CAD (summed stress score [SSS] ≤ 8), those with moderate to severe CAD (SSS > 8) had significantly higher A-FABP concentrations. However, the difference was attenuated in the subgroup of patients with heart failure. In the correlation analyses, A-FABP level was correlated with age, body mass index, waist circumference, levels of creatinine, fasting glucose, high-sensitivity C-reactive protein, N-terminal pro-brain natriuretic peptide, adiponectin, and several echocardiographic parameters, including left ventricular ejection fraction. Multivariate logistic regression analysis demonstrated that the A-FABP level was not only associated with higher SSS (odds ratio, 1.30; 95% confidence interval [CI], 1.01-1.69; P = 0.048), but also an independent risk factor for heart failure (odds ratio 2.71, 95% CI, 1.23-5.94; P = 0.013).

CONCLUSIONS

Serum A-FABP levels not only were associated with myocardial perfusion abnormalities and left ventricular function, but also predicted the presence of heart failure in our patients with CAD.

Low intrinsic exercise capacity in rats predisposes to age-dependent cardiac remodeling independent of macrovascular function

Rats selectively bred for low (LCR) or high (HCR) intrinsic running capacity simultaneously present with contrasting risk factors for cardiovascular and metabolic disease. However, the impact of these phenotypes on left ventricular (LV) morphology and microvascular function, and their progression with aging, remains unresolved. We tested the hypothesis that the LCR phenotype induces progressive age-dependent LV remodeling and impairments in microvascular function, glucose utilization, and β-adrenergic responsiveness, compared with HCR. Hearts and vessels isolated from female LCR (n = 22) or HCR (n = 26) were studied at 12 and 35 wk. Nonselected N:NIH founder rats (11 wk) were also investigated (n = 12). LCR had impaired glucose tolerance and elevated plasma insulin (but not glucose) and body-mass at 12 wk compared with HCR, with early LV remodeling. By 35 wk, LV prohypertrophic and glucose transporter GLUT4 gene expression were up- and downregulated, respectively. No differences in LV β-adrenoceptor expression or cAMP content between phenotypes were observed. Macrovascular endothelial function was predominantly nitric oxide (NO)-mediated in both phenotypes and remained intact in LCR for both age-groups. In contrast, mesenteric arteries microvascular endothelial function, which was impaired in LCR rats regardless of age. At 35 wk, endothelial-derived hyperpolarizing factor-mediated relaxation was impaired whereas the NO contribution to relaxation is intact. Furthermore, there was reduced β2-adrenoceptor responsiveness in both aorta and mesenteric LCR arteries. In conclusion, diminished intrinsic exercise capacity impairs systemic glucose tolerance and is accompanied by progressive development of LV remodeling. Impaired microvascular perfusion is a likely contributing factor to the cardiac phenotype.

Regional evidence of modulation of cardiac adiponectin level in dilated cardiomyopathy: pilot study in a porcine animal model

Background

The role of systemic and myocardial adiponectin (ADN) in dilated cardiomyopathy is still debated. We tested the regulation of both systemic and myocardial ADN and the relationship with AMP-activated protein kinase (AMPK) activity in a swine model of non-ischemic dilated cardiomyopathy.

Methods and results

Cardiac tissue was collected from seven instrumented adult male minipigs by pacing the left ventricular (LV) free wall (180 beats/min, 3 weeks), both from pacing (PS) and opposite sites (OS), and from five controls. Circulating ADN levels were inversely related to global and regional cardiac function. Myocardial ADN in PS was down-regulated compared to control (p < 0.05), yet ADN receptor 1 was significantly up-regulated (p < 0.05). No modifications of AMPK were observed in either region of the failing heart. Similarly, myocardial mRNA levels of PPARγ, PPARα, TNFα, iNOS were unchanged compared to controls.

Conclusions

Paradoxically, circulating ADN did not show any cardioprotective effect, confirming its role as negative prognostic biomarker of heart failure. Myocardial ADN was reduced in PS compared to control in an AMPK-independent fashion, suggesting the occurrence of novel mechanisms by which reduced cardiac ADN levels may regionally mediate the decline of cardiac function.

T(-786)→C polymorphism of the endothelial nitric oxide synthase gene is associated with insulin resistance in patients with ischemic or non ischemic cardiomyopathy

BACKGROUND

Insulin resistance (IR) and endothelial dysfunction are frequently associated in cardiac disease. The T(-786)→C variant in the promoter region of the endothelial nitric oxide synthase (eNOS) gene has been associated with IR in both non-diabetic and diabetic subjects. Aim of the study was to assess the reciprocal relationships between T(-786)→C eNOS polymorphism and IR in ischemic and non-ischemic cardiomyopathy.

METHOD

A group of 132 patients (108 males, median age 65 years) with global left ventricular (LV) dysfunction secondary to ischemic or non-ischemic heart disease was enrolled. Genotyping of T(-786)→C eNOS gene promoter, fasting glucose, insulin, and insulin resistance (defined as HOMA-IR index > 2.5) were determined in all patients.

RESULTS

Genotyping analysis yielded 37 patients homozygous for the T allele (TT), 70 heterozygotes (TC) and 25 homozygous for C (CC). Patients with CC genotype had significantly higher systemic arterial pressure, blood glucose, plasma insulin and HOMA index levels than TT. At multivariate logistic analysis, the history of hypertension and the genotype were the only predictors of IR. In particular, CC genotype increased the risk of IR (CI% 1.4-15.0, p < 0.01) 4.5-fold. The only parameter independently associated with the extent of LV dysfunction and the presence of heart failure (HF) was the HOMA index (2.4 CI% 1.1-5.6, p < 0.04).

CONCLUSIONS

T(-786)→C eNOS polymorphism was the major independent determinant of IR in a population of patients with ischemic and non-ischemic cardiomyopathy. The results suggest that a condition of primitive eNOS lower expression can predispose to an impairment of glucose homeostasis, which in turn is able to affect the severity of heart disease.

Insulin resistance and heart failure: molecular mechanisms

This article addresses the issue of insulin resistance and associated reductions in cardiac insulin metabolic signaling, which is emerging as a major factor in the development of heart failure, and assumes more importance because of an epidemic increase in obesity and the cardiorenal metabolic syndrome in our aging population. The effects of cardiac insulin resistance are exacerbated by metabolic, endocrine, and cytokine alterations associated with systemic insulin resistance. Understanding the molecular mechanisms linking insulin resistance and heart failure may help to design new and more effective mechanism-based drugs to improve myocardial and systemic insulin resistance.

Heart failure among South Asians: a narrative review of risk, nature, outcomes and management

Individuals of South Asian descent have a high prevalence of comorbidities that are risk factors for the development of heart failure (HF), including diabetes mellitus and metabolic syndrome. However, little is known about the prevalence of HF, its management and prognosis for this population compared to Caucasians. Therefore, a literature review relating to the nature, outcome and treatment of HF in South Asian patients compared to Caucasians was conducted. It was anticipated that collating existing studies in this manner would be useful for guiding professionals in managing HF within this ethnic group, given that to achieve optimal care, regimens need to take into account cultural differences that may impact on adherence. Reviewed literature showed that South Asians with HF were more likely to be younger and have diabetes and hypertension. These papers also implied that outcomes for South Asians with HF were similar or even better than for Caucasians. The review highlighted the under-representation of South Asians in HF trials, meaning that evidence-based recommendations tailored to this specific population are limited. This is an important consideration because ethnic differences in response to medication have been reported; it cannot be assumed that treatments shown to work for Caucasians will be efficacious for those from minority ethnic groups.

Unrecognized glucose intolerance is common in pulmonary arterial hypertension

BACKGROUND

Animal and human data suggest insulin resistance is common in pulmonary arterial hypertension (PAH). Although routine assessment of insulin resistance is difficult, hemoglobin A(1c) (HbA(1c)) is a sensitive test to detect diabetes mellitus (DM) and those at high risk for DM. We aimed to define the prevalence of elevated HbA(1c) in PAH patients and to correlate HbA(1c) levels with functional assessment.

METHODS

HbA(1c) was measured in 41 PAH patients without a diagnosis of DM, along with demographic, functional, and hemodynamic data. Using published criteria, HbA(1c) ≤ 5.9% defined normal, 6.0% to 6.4% was glucose intolerance, and ≥ 6.5% was DM.

RESULTS

Twenty-three patients (56%) had HbA(1c) ≥ 6.0%, and 6 (15%) had unrecognized DM (HbA(1c) ≥ 6.5%). Age and body mass index were similar in patients with HbA(1c) ≥ 6.0% vs < 6.0%. There was a trend towards lower mean 6-minute walk distance in patients with elevated HbA(1c) (331.0 ± 126.6 vs 413.6 ± 74.9 meters, p = 0.07). The 6-month event-free survival was not significantly different in patients with elevated HbA(1c).

CONCLUSIONS

Unrecognized glucose intolerance as assessed by HbA(1c) is common in PAH. Further studies are needed to discern if glucose or insulin dysregulation mediates PAH pathogenesis or is secondary to advanced PAH.