A comparison of the pathological spectrum of hypertensive, diabetic, and hypertensive-diabetic heart disease

The theatrics of collagens in the myocardium: the supreme architect of the fibrotic heart

Heart failure (HF) mediated by cardiac fibrosis (CF) is characterized by an excessive accumulation of collagen-based extracellular matrix (ECM) in the myocardium. CF is a common pathophysiological condition in many heart diseases and can be distinctly categorized into two types: replacement and interstitial. In ischemic heart diseases, sudden loss of cardiomyocytes leads to the replacement of CF to prevent ventricular rupture. In contrast, excessive collagen deposition in the interstitial space between cardiomyocytes (often in response to pressure overload, chronic cardiac stress, hypertension, etc.) is termed interstitial CF. The progression of HF due to cardiac fibrosis is mainly driven by compromised diastolic function, resulting from increased stiffness of the heart wall muscle due to collagen-based scar formation. Increased myocardial stiffness is primarily catalyzed by the differential cross linking of deposited collagens forming the scar in the fibrotic heart. Although collagen deposition remained a hallmark of fibrosis, the pathophysiological progression due to biochemical alterations and mechanistic discrepancy of collagens across cardiac fibrosis subtypes remains elusive. With the advent of next-generation RNA sequencing and high-resolution mass spectrometry, mechanistic insights into collagen-mediated scar maturation have gained impetus. A deeper understanding of the spatiocellular transcriptional heterogeneity and site-specific collagen posttranslational modifications (PTMs) in maneuvering ECM remodeling is gaining attention. The unexplored mechanisms of posttranslational modifications and subsequent collagen cross linking in various cardiac fibrosis may provide the prime target for therapeutic interventions. This review comprehensively summarizes the detailed pattern, role, signaling, and mechanical contributions of different collagens and their PTMs, including cross-linking patterns as newer therapeutic regimens during cardiac fibrosis.

Clinical Impact of Glucose Levels on Patient Outcome after Transcatheter Aortic Valve Replacement

Background

Limited data are available for evaluating the effect of blood glucose on transcatheter aortic valve replacement (TAVR) outcomes in patients with diabetes. We aimed to assess the impact of glucose levels on short-term and long-term adverse outcomes in patients undergoing TAVR.

Methods and Results

Data from severe aortic stenosis (AS) patients who underwent TAVR from 2010 to 2022 were collected retrospectively. In total, 615 patients were enrolled in the study: Among the total patient population, 43% had diabetes mellitus (DM), with a mean hemoglobin A1c (HbA1c) level of 7.4 ± 2.5. Within this cohort, 33% were classified as having uncontrolled diabetes, while 17% were considered well-controlled. Diabetic patients were younger (80.7 ± 6.8 vs. 82.0 ± 6.8 years, p = 0.001) and had more cardiovascular risk factors. No significant differences were found in outcomes between the two groups during the twelve-year follow-up. A multivariable logistic regression analysis was conducted on 270 DM patients to examine the impact of blood glucose levels and HbA1c on outcomes such as arrhythmia, stroke, and acute kidney injury (AKI). For arrhythmia, the odds ratio for HbA1c and blood glucose were 1.1039 (p = 0.23), and 0.998 (p = 0.76), indicating no significant associations. In stroke cases, HbA1c had an odds ratio of 1.194 (p = 0.36), while an odds ratio of 1.020 (p = 0.013) for blood glucose indicated a significant association. Notably, for AKI, the odds ratio for HbA1c was 2.304 (p = 0.02), indicating a significant link between higher HbA1c levels and increased AKI risk, with blood glucose levels trending toward significance (odds ratio = 1.0137, p = 0.061).

Conclusions

Diabetic status is a predictor of short-term outcomes following TAVR. Thus, these screening parameters should be included in risk assessment tools for TAVR candidates.

Association of Glycemic Control With Right Ventricular Function Assessed by Two-Dimensional Speckle-Tracking and Three-Dimensional Echocardiography in Type 2 Diabetes Mellitus

BACKGROUND

Right ventricular (RV) involvement has been reported in type 2 diabetes mellitus (T2DM). The relationship between glycemic control and RV function remains unknown. We aimed to investigate the association between glycemic control and RV function assessed by two-dimensional speckle-tracking echocardiography and three-dimensional echocardiography in T2DM individuals.

METHODS

This study prospectively enrolled 207 patients with T2DM and 84 individuals with normal glucose metabolism. The T2DM patients were divided into 2 subgroups according to glycated hemoglobin (HbA1c) level: controlled (HbA1c < 7.0%, n = 91) and uncontrolled subgroup (HbA1c ≥ 7.0%, n = 116). Right venticular free wall longitudinal strain (RVFWLS) was acquired by two-dimensional speckle-tracking echocardiography, and RV volumes and RV ejection fraction (RVEF) were assessed using three-dimensional echocardiography . Right ventricular coupling to pulmonary circulation was defined as the ratio of RVFWLS/pulmonary artery systolic pressure (PASP).

RESULTS

Controlled and uncontrolled T2DM subgroups had impaired RV function as reflected by reduced RVFWLS and RVEF compared to the normal glucose metabolism group. The reduction in RVFWLS was more pronounced in the uncontrolled subgroup than in the controlled subgroup (P < .001), whereas no significant difference was found in RVEF between these 2 T2DM subgroups. Higher PASP and lower RVFWLS/PASP ratio were also noted in uncontrolled T2DM patients. Additionally, the incidence of RV dysfunction was significantly higher in the uncontrolled T2DM patients than in the controlled subgroup (43.1% vs 17.6%, P < .001). After adjustment for potential clinical confounders, PASP, and left ventricular parameters, HbA1c level was independently associated with RVFWLS (β = 0.290, P = .003) and RVFWLS/PASP ratio (β = 0.028, P = .006).

CONCLUSIONS

Subclinical RV myocardial dysfunction is present in T2DM patients and is more pronounced in patients with uncontrolled blood glucose. HbA1c level is independently associated with subclinical RV myocardial dysfunction, providing further insight into a possible link between poor glycemic control and diabetic cardiomyopathy.

The fate and role of the pericytes in myocardial diseases

The adult mammalian heart contains a large population of pericytes that play important roles in homeostasis and disease. In the normal heart, pericytes regulate microvascular permeability and flow. Myocardial diseases are associated with marked alterations in pericyte phenotype and function. This review manuscript discusses the role of pericytes in cardiac homeostasis and disease. Following myocardial infarction (MI), cardiac pericytes participate in all phases of cardiac repair. During the inflammatory phase, pericytes may secrete cytokines and chemokines and may regulate leukocyte trafficking, through formation of intercellular gaps that serve as exit points for inflammatory cells. Moreover, pericyte contraction induces microvascular constriction, contributing to the pathogenesis of 'no-reflow' in ischemia and reperfusion. During the proliferative phase, pericytes are activated by growth factors, such as transforming growth factor (TGF)-β and contribute to fibrosis, predominantly through secretion of fibrogenic mediators. A fraction of pericytes acquires fibroblast identity but contributes only to a small percentage of infarct fibroblasts and myofibroblasts. As the scar matures, pericytes form a coat around infarct neovessels, promoting stabilization of the vasculature. Pericytes may also be involved in the pathogenesis of chronic heart failure, by regulating inflammation, fibrosis, angiogenesis and myocardial perfusion. Pericytes are also important targets of viral infections (such as SARS-CoV2) and may be implicated in the pathogenesis of cardiac complications of COVID19. Considering their role in myocardial inflammation, fibrosis and angiogenesis, pericytes may be promising therapeutic targets in myocardial disease.

High left ventricular mass associated with increased risk of incident diabetes

Evidence for the role of electrocardiography or echocardiography in determining left ventricular hypertrophy for the risk of diabetes is still controversial. We aimed to explore whether left ventricular mass, as measured by these methods, is associated with the risk of diabetes in a community population. We recruited 2696 participants aged 35 years or older without diabetes who had undergone screening with electrocardiography and echocardiography. Left ventricular mass index (LVMI) was calculated using a formula, and participants were divided into tertiles based on their LVMI tertiles. During a median follow-up period of median, 8.9 years, a total of 405 participants developed diabetes. The incidence and risk of diabetes significantly increased with higher LVMI tertiles. Multivariate Cox regression analysis demonstrated that individuals in the highest LVMI tertile had a greater likelihood of developing incident diabetes, with a hazard ratio of 1.40 (95% CI 1.06-1.91), even after adjusting related covariates. The highest risk of diabetes was observed in the presence of both the uppermost LVMI tertile and electrocardiographically determined left ventricular hypertrophy for the Chinese population. Left ventricular hypertrophy identified by either electrocardiography or echo may serve as a surrogate marker for identifying the risk of diabetes in clinical practice.

Chrysin-based supramolecular cyclodextrin-calixarene drug delivery system: a novel approach for attenuating cardiac fibrosis in chronic diabetes

Introduction: Cardiac fibrosis is strongly induced by diabetic conditions. Both chrysin (CHR) and calixarene OTX008, a specific inhibitor of galectin 1 (Gal-1), seem able to reduce transforming growth factor beta (TGF-β)/SMAD pro-fibrotic pathways, but their use is limited to their low solubility. Therefore, we formulated a dual-action supramolecular system, combining CHR with sulfobutylated β-cyclodextrin (SBECD) and OTX008 (SBECD + OTX + CHR). Here we aimed to test the anti-fibrotic effects of SBECD + OTX + CHR in hyperglycemic H9c2 cardiomyocytes and in a mouse model of chronic diabetes. Methods: H9c2 cardiomyocytes were exposed to normal (NG, 5.5 mM) or high glucose (HG, 33 mM) for 48 h, then treated with SBECD + OTX + CHR (containing OTX008 0.75-1.25-2.5 µM) or the single compounds for 6 days. TGF-β/SMAD pathways, Mitogen-Activated Protein Kinases (MAPKs) and Gal-1 levels were assayed by Enzyme-Linked Immunosorbent Assays (ELISAs) or Real-Time Quantitative Reverse Transcription Polymerase chain reaction (qRT-PCR). Adult CD1 male mice received a single intraperitoneal (i.p.) administration of streptozotocin (STZ) at a dosage of 102 mg/kg body weight. From the second week of diabetes, mice received 2 times/week the following i.p. treatments: OTX (5 mg/kg)-SBECD; OTX (5 mg/kg)-SBECD-CHR, SBECD-CHR, SBECD. After a 22-week period of diabetes, mice were euthanized and cardiac tissue used for tissue staining, ELISA, qRT-PCR aimed to analyse TGF-β/SMAD, extracellular matrix (ECM) components and Gal-1. Results: In H9c2 cells exposed to HG, SBECD + OTX + CHR significantly ameliorated the damaged morphology and reduced TGF-β1, its receptors (TGFβR1 and TGFβR2), SMAD2/4, MAPKs and Gal-1. Accordingly, these markers were reduced also in cardiac tissue from chronic diabetes, in which an amelioration of cardiac remodeling and ECM was evident. In both settings, SBECD + OTX + CHR was the most effective treatment compared to the other ones. Conclusion: The CHR-based supramolecular SBECD-calixarene drug delivery system, by enhancing the solubility and the bioavailability of both CHR and calixarene OTX008, and by combining their effects, showed a strong anti-fibrotic activity in rat cardiomyocytes and in cardiac tissue from mice with chronic diabetes. Also an improved cardiac tissue remodeling was evident. Therefore, new drug delivery system, which could be considered as a novel putative therapeutic strategy for the treatment of diabetes-induced cardiac fibrosis.

Strong independent association between third-degree AV-block and diabetes mellitus using a large database

BACKGROUND

Recent data suggests an association between DM and third-degree AV- Block. The goal of this study was to evaluate the independent association between diabetes and third-degree AV-Block using a very large database.

METHOD

We used ICD-9 Codes for DM and third-degree AV-block from the Nationwide Inpatient Sample (NIS) database. We randomly selected the 1992 and 2002 databases which are 10 years apart as two independent samples. We used uni- and multi-variate analysis to evaluate this association.

RESULTS

1992 database contained a total of 6,195,744 patients. Diabetes occurred in (0.5 %) of patients with third-degree AV-block vs. (0.2 %) of the control (OR: 2.15, CI 2.06-2.25, p < 0.0001). 2002 database contained a total of 7,853,982 patients. Diabetes occurred in (0.4 %) of patients with third-degree AV-block vs. (0.2 %) of the control (OR: 1.86, CI: 1.80-1.93, p < 0.0001). Using Multivariate analysis adjusting for age, congestive heart failure, and coronary artery disease, DM remained independently associated with third-degree AV block in both databases. (for 1999: OR: 2.54, CI 2.51-2.57, p < 0.0001 and for 2002 OR: 1.56, CI 1.55-1.57, p < 0.0001).

CONCLUSION

DM is independently associated with third-degree AV-block with persistent association over a period of 10 years. The cause of this association warrants further investigation.

Haemodynamic effects of hypertension and type 2 diabetes: Insights from a 4D flow MRI-based personalized cardiovascular mathematical model

Type 2 diabetes (T2D) and hypertension increase the risk of cardiovascular diseases mediated by whole-body changes to metabolism, cardiovascular structure and haemodynamics. The haemodynamic changes related to hypertension and T2D are complex and subject-specific, however, and not fully understood. We aimed to investigate the haemodynamic mechanisms in T2D and hypertension by comparing the haemodynamics between healthy controls and subjects with T2D, hypertension, or both. For all subjects, we combined 4D flow magnetic resonance imaging data, brachial blood pressure and a cardiovascular mathematical model to create a comprehensive subject-specific analysis of central haemodynamics. When comparing the subject-specific haemodynamic parameters between the four groups, the predominant haemodynamic difference is impaired left ventricular relaxation in subjects with both T2D and hypertension compared to subjects with only T2D, only hypertension and controls. The impaired relaxation indicates that, in this cohort, the long-term changes in haemodynamic load of co-existing T2D and hypertension cause diastolic dysfunction demonstrable at rest, whereas either disease on its own does not. However, through subject-specific predictions of impaired relaxation, we show that altered relaxation alone is not enough to explain the subject-specific and group-related differences; instead, a combination of parameters is affected in T2D and hypertension. These results confirm previous studies that reported more adverse effects from the combination of T2D and hypertension compared to either disease on its own. Furthermore, this shows the potential of personalized cardiovascular models in providing haemodynamic mechanistic insights and subject-specific predictions that could aid in the understanding and treatment planning of patients with T2D and hypertension. KEY POINTS: The combination of 4D flow magnetic resonance imaging data and a cardiovascular mathematical model allows for a comprehensive analysis of subject-specific haemodynamic parameters that otherwise cannot be derived non-invasively. Using this combination, we show that diastolic dysfunction in subjects with both type 2 diabetes (T2D) and hypertension is the main group-level difference between controls, subjects with T2D, subjects with hypertension, and subjects with both T2D and hypertension. These results suggest that, in this relatively healthy population, the additional load of both hypertension and T2D affects the haemodynamic function of the left ventricle, whereas each disease on its own is not enough to cause significant effects under resting conditions. Finally, using the subject-specific model, we show that the haemodynamic effects of diastolic dysfunction alone are not sufficient to explain all the observed haemodynamic differences. Instead, additional subject-specific variations in cardiac and vascular function combine to explain the complex haemodynamics of subjects affected by hypertension and/or T2D.

Review: Acetylation Mechanisms andTargeted Therapies in Cardiac Fibrosis

Cardiac fibrosis is a common pathophysiological remodeling process that occurs in a variety of cardiovascular diseases and greatly influences heart structure and function, progressively leading to the development of heart failure. However, to date, few effective therapies for cardiac fibrosis exist. Abnormal proliferation, differentiation, and migration of cardiac fibroblasts are responsible for the excessive deposition of extracellular matrix in the myocardium. Acetylation, a widespread and reversible protein post-translational modification, plays an important role in the development of cardiac fibrosis by adding acetyl groups to lysine residues. Many acetyltransferases and deacetylases regulate the dynamic alterations of acetylation in cardiac fibrosis, regulating a range of pathogenic conditions including oxidative stress, mitochondrial dysfunction, and energy metabolism disturbance. In this review, we demonstrate the critical roles that acetylation modifications caused by different types of pathological injury play in cardiac fibrosis. Furthermore, we propose therapeutic acetylation-targeting strategies for the prevention and treatment of patients with cardiac fibrosis.

Gentiopicroside alleviates cardiac inflammation and fibrosis in T2DM rats through targeting Smad3 phosphorylation

BACKGROUND

Cardiac fibrosis is a major structural change observed in the heart of patients with type 2 diabetes mellitus (T2DM), ultimately resulting in heart failure (HF). Suppression of inflammation is an effective therapeutic strategy for treating cardiac fibrosis and HF. Gentiopicroside (GPS), the primary component of Gentiana manshurica Kitagawa, possess potent anti-inflammatory activity. However, its cardioprotective role remains elusive.

PURPOSE

We explored the potential cardioprotective role of GPS in T2DM rats and its underlying mechanisms.

METHODS

T2DM rats built by high-fat diet and streptozotocin were orally administered 25, 50, or 100 mg/kg GPS, daily for 8 weeks. The positive control drug was Metformin (200 mg/kg/day). Primary cardiac fibroblasts (CFs) were induced by high glucose (30 mM) and subsequently treated with GPS (100 μM). Cardiac function and pathological changes were analyzed using echocardiography and histological staining. Potential targets of GPS were predicted using Molecular docking. Real-time PCR as well as western blotting were applied to verify the expression of objective genes.

RESULTS

All three doses reduced fasting blood glucose levels, but only 50 and 100 mg/kg GPS improved cardiac function and alleviated inflammation and fibrosis in T2DM rats. GPS (100 mg/kg) exhibited a better effect, similar to that of metformin. Mechanistically, binding between GPS and the MH2 domain of Smad3 blocked high glucose-induced Smad3 phosphorylation, thus attenuating inflammation, oxidative stress, and activation in CFs.

CONCLUSION

We, for the first time, demonstrated that GPS improved cardiac function in T2DM rats and elucidated the underlying mechanism through which GPS targeted Smad3 phosphorylation to suppress inflammation and activation in CFs, thereby revealing the potential application of GPS in HF therapy.

Bariatric surgery for diabetic comorbidities: A focus on hepatic, cardiac and renal fibrosis

Continuously rising trends in diabetes render this disease spectrum an epidemic proportion worldwide. As the disease progresses, the pathological effects of diabetes may impair the normal function of several vital organs, eventually leading to increase the risk of other diabetic comorbidities with advanced fibrosis such as non-alcoholic fatty liver disease, diabetic cardiomyopathy, and diabetic kidney disease. Currently, lifestyle changes and drug therapies of hypoglycemic and lipid-lowering are effective in improving multi-organ function, but therapeutic efficacy is difficult to maintain due to poor compliance and drug reactions. Bariatric surgery, including sleeve gastrectomy and Roux-en-Y gastric bypass surgery, has shown better results in terms of prognosis for diabetes through long-term follow-up. Moreover, bariatric surgery has significant long-term benefits on the function of the heart, liver, kidneys, and other organs through mechanisms associated with reversal of tissue fibrosis. The aim of this review is to describe the impact of type 2 diabetes mellitus on hepatic, cardiac and renal fibrosis and to summarize the potential mechanisms by which bariatric surgery improves multiple organ function, particularly reversal of fibrosis.

Canadian Contributions in Fibroblast Biology

Fibroblasts are stromal cells found in virtually every tissue and organ of the body. For many years, these cells were often considered to be secondary in functional importance to parenchymal cells. Over the past 2 decades, focused research into the roles of fibroblasts has revealed important roles for these cells in the homeostasis of healthy tissue, and has demonstrated that activation of fibroblasts to myofibroblasts is a key step in disease initiation and progression in many tissues, with fibrosis now recognized as not only an outcome of disease, but also a central contributor to tissue dysfunction, particularly in the heart and lungs. With a growing understanding of both fibroblast and myofibroblast heterogeneity, and the deciphering of the humoral and mechanical cues that impact the phenotype of these cells, fibroblast biology is rapidly becoming a major focus in biomedical research. In this review, we provide an overview of fibroblast and myofibroblast biology, particularly in the heart, and including a discussion of pathophysiological processes such as fibrosis and scarring. We then discuss the central role of Canadian researchers in moving this field forwards, particularly in cardiac fibrosis, and highlight some of the major contributions of these individuals to our understanding of fibroblast and myofibroblast biology in health and disease.

The Dynamic Characteristics of Myocardial Contractility and Extracellular Volume in Type 2 Diabetes Mellitus Mice Investigated by 7.0T Cardiac Magnetic Resonance

Type 2 diabetes mellitus (T2DM) is associated with a high prevalence of diastolic dysfunction and congestive heart failure. A potential contributing factor is the accelerated accumulation of diffuse myocardial fibrosis and stiffness. Novel cardiac magnetic resonance (CMR) imaging techniques can identify both myocardial fibrosis and contractility quantitatively. This study aimed to investigate the dynamic characteristics of the myocardial strain and altered extracellular volume (ECV) fraction as determined by 7.0 T CMR in T2DM mice. C57Bl/6J mice were randomly divided into T2DM (fed a high-fat diet) and control (fed a normal diet) groups. They were scanned on 7.0 T MRI every 4 weeks until the end of week 24. The CMR protocol included multi-slice cine imaging to assess left ventricle strain and strain rate, and pre- and post-contrast T1 mapping images to quantify ECV. The ECV in the T2DM mice was significantly higher (p < 0.05) than that in the control group since week 12 with significantly impaired myocardial strain (p < 0.05). A significant linear correlation was established between myocardial strain and ECV (p < 0.001) and left ventricular-ejection fraction and ECV (p = 0.003). The results suggested that CMR feature tracking-derived myocardial strain analysis can assess functional abnormalities that may be associated with ECM alterations in diabetic cardiomyopathy, contributing to the study of diabetic therapy effects.

Quantitative assessment of left atrial functions by speckle tracking echocardiography in hypertensive patients with and without retinopathy

PURPOSE

The association between hypertensive retinopathy and left atrial (LA) impairment is unknown. Accordingly, it was aimed to investigate the possible relationship between hypertensive retinopathy and LA phasic functions by means of two-dimensional speckle-tracking echocardiography (2D-STE).

METHODS

A total of 124 hypertensive patients and 27 control subjects were included in the study. LA reservoir strain (LA_S-S ), LA conduit strain (LA_S-E ), and LA booster strain (LA_S-A ) parameters were used to evaluate LA myocardial functions.

RESULTS

Hypertensive patients (with and without retinopathy) displayed an obvious reduction in the LA reservoir strain (LA_S-S )_, and LA conduit strain (LA_S-E ). Moreover, further impairment in LA reservoir and conduit strain was found in patients with hypertensive retinopathy than in the isolated hypertensive patients. There were no significant differences in LA booster strain (LA_S-A ) among the three groups. Impaired LA_S-S (OR: 0.764, CI: 0.657-0.888, and p < 0.001), LA_S-E (OR: 0.754, CI: 0.634-0.897, and p = 0.001), and hypertension (HT) duration (OR: 2.345, CI: 1.568-3.507, and p < 0.001) were shown to be independent predictors of hypertensive retinopathy.

CONCLUSION

Impaired LA reservoir and conduit strain may be used to predict hypertensive patients at higher risk of developing hypertensive retinopathy, and to determine which patients should be followed more closely for hypertensive retinopathy.

Current landscape of preclinical models of diabetic cardiomyopathy

Patients with diabetes have an increased risk of developing heart failure, preceded by (often asymptomatic) cardiac abnormalities, collectively called diabetic cardiomyopathy (DC). Diabetic heart failure lacks effective treatment, remaining an urgent, unmet clinical need. Although structural and functional characteristics of the diabetic human heart are well defined, clinical studies lack the ability to pinpoint the specific mechanisms responsible for DC. Preclinical animal models represent a vital component for understanding disease aetiology, which is essential for the discovery of new targeted treatments for diabetes-induced heart failure. In this review, we describe the current landscape of preclinical DC models (genetic, pharmacologically induced, and diet-induced models), highlighting their strengths and weaknesses and alignment to features of the human disease. Finally, we provide tools, resources, and recommendations to assist future preclinical translation addressing this knowledge gap.

Metabolic syndrome in hypertensive and non-hypertensive subjects

BACKGROUND AND AIMS

Hypertension is a major risk factor of cardiovascular diseases (CVDs), which attributes to one-third of all deaths worldwide. It is also considered as a key feature of metabolic syndrome (MetS). The aim of the present study was to compare the presence of characteristic features of MetS in hypertensive and non-hypertensive males and females and find out the percentages of MetS in hypertensive and non-hypertensive adults.

METHODS

This was a cross-sectional study, involving 120 participants that included 60 hypertensives and 60 non-hypertensives (35-55 years). Data were obtained through an interviewer-administered questionnaire. Fasting blood sugar (FBS) and lipid parameters [triglyceride-(TG), high density lipoprotein (HDL)] were analyzed, and waist circumference (WC) was measured. Percentages of MetS among hypertensive and non-hypertensive groups were determined according to both modified Adult Treatment Panel III (ATP III) and new International Diabetes Federation (IDF) criteria. Results were analyzed using SPSS version 21.

RESULTS

Among the characteristic features of MetS, mean FBS and WC were significantly higher in hypertensive males compared with non-hypertensive males (P < .001 and P = .002 respectively), while mean value of TG was significantly higher (P = .005) in hypertensive females compared with non-hypertensive females. Further, the percentage of subjects in the total hypertensive group with increased FBS and increased WC was significantly higher than the non- hypertensive group. The percentage of subjects with MetS was significantly (P < .001) higher in hypertensive group (68%) compared with non-hypertensive group (20%) according to modified ATP III criteria. When compared with new IDF criteria, it was 63% and 20%, respectively.

CONCLUSION

The percentage of subjects with increased FBS, WC, and MetS was significantly higher in the hypertensive group compared with non-hypertensives group. These findings emphasize the urgent need to develop national strategies for early detection, and to take preventive measures to make people aware of the impact of metabolic syndrome.

Fibrosis of the diabetic heart: Clinical significance, molecular mechanisms, and therapeutic opportunities

In patients with diabetes, myocardial fibrosis may contribute to the pathogenesis of heart failure and arrhythmogenesis, increasing ventricular stiffness and delaying conduction. Diabetic myocardial fibrosis involves effects of hyperglycemia, lipotoxicity and insulin resistance on cardiac fibroblasts, directly resulting in increased matrix secretion, and activation of paracrine signaling in cardiomyocytes, immune and vascular cells, that release fibroblast-activating mediators. Neurohumoral pathways, cytokines, growth factors, oxidative stress, advanced glycation end-products (AGEs), and matricellular proteins have been implicated in diabetic fibrosis; however, the molecular links between the metabolic perturbations and activation of a fibrogenic program remain poorly understood. Although existing therapies using glucose- and lipid-lowering agents and neurohumoral inhibition may act in part by attenuating myocardial collagen deposition, specific therapies targeting the fibrotic response are lacking. This review manuscript discusses the clinical significance, molecular mechanisms and cell biology of diabetic cardiac fibrosis and proposes therapeutic targets that may attenuate the fibrotic response, preventing heart failure progression.

The Acute Effects of Different Spironolactone Doses on Oxidative Stress in Streptozotocin-Induced Diabetic Rats

Cardiovascular diseases are the leading cause of morbidity and mortality in patients with diabetes mellitus. Increased bioavailability of reactive oxygen species is defined as oxidative stress and is noticed in type 2 DM and reduced antioxidant enzymes expression/ activity. Aldosterone, an adrenal hormone, is secreted due to renin-angiotensin–aldosterone system activation, representing one of the fundamental physiological reactions in CVD. Spironolactone, a mineralocorticoid receptor antagonist, uses enhanced coronary microvascular function, suggesting a beneficial role of aldosterone in preventing diabetic cardiovascular complications in patients with type 2 DM. In this study, we evaluated the influence of spironolactone's acute administration on oxidative stress in rats with diabetes mellitus induced by streptozotocin. The present study was carried out on 40 adult male Wistar albino rats (8 weeks old). Rats were randomly divided into 4 groups (10 animals per group): healthy rats treated with 0.1 μM of spironolactone, diabetic rats treated with 0.1 μM of spironolactone, healthy rats treated with 3 μM of spironolactone, and diabetic rats treated with 3 μM of spironolactone. Spironolactone achieved different effects on oxidative stress parameters when given acutely in different doses in diabetic and healthy rats. In lower doses, spironolactone's acute administration reached lowered parameters of oxidative stress in healthy rats better than higher doses of spironolactone. In contrast, in the diabetic group, acute effects of higher doses of spironolactone lowered oxidative stress parameters better than lower spironolactone doses.

Hyperglycemia and hyperlipidemia can induce morphophysiological changes in rat cardiac cell line

H9c2 cardiac cells were incubated under the control condition and at different hyperglycemic and hyperlipidemic media, and the following parameters were determined and quantified: a) cell death, b) type of cell death, and c) changes in cell length, width and height. Of all the proven media, the one that showed the greatest differences compared to the control was the medium glucose (G) 33 mM + 500 μM palmitic acid. This condition was called the hyperglycemic and hyperlipidemic condition (HHC). Incubation of H9c2 cells in HHC promoted 5.2 times greater total cell death when compared to the control. Of the total death ofthe HHC cells, 38.6% was late apoptotic and 8.3% early apoptotic. HHC also changes cell morphology. The reordering of the actin cytoskeleton and cell stiffness was also studied in control and HHC cells. The actin cytoskeleton was quantified and the number and distance of actin bundles were not the same in the control as under HHC. Young's modulus images show a map of cell stiffness. Cells incubated in HHC with the reordered actin cytoskeleton were stiffer than those incubated in control. The region of greatest stiffness was the peripheral zone of HHC cells (where the number of actin bundles was higher and the distance between them smaller). Our results suggest a correlation between the reordering of the actin cytoskeleton and cell stiffness. Thus, our study showed that HHC can promote morphophysiological changes in rat cardiac cells confirming that gluco-and lipotoxicity may play a central role in the development of diabetic cardiomyopathy.

Concurrent diabetes and heart failure: interplay and novel therapeutic approaches

Diabetes mellitus increases the risk of developing heart failure, and the co-existence of both diseases worsens cardiovascular outcomes, hospitalization and the progression of heart failure. Despite current advancements on therapeutic strategies to manage hyperglycemia, the likelihood of developing diabetes-induced heart failure is still significant, especially with the accelerating global prevalence of diabetes and an ageing population. This raises the likelihood of other contributing mechanisms beyond hyperglycemia in predisposing diabetic patients to cardiovascular disease risk. There has been considerable interest in understanding the alterations in cardiac structure and function in the diabetic patients, collectively termed as "diabetic cardiomyopathy". However, the factors that contribute to the development of diabetic cardiomyopathies is not fully understood. This review summarizes the main characteristics of diabetic cardiomyopathies, and the basic mechanisms that contribute to its occurrence. This includes perturbations in insulin resistance, fuel preference, reactive oxygen species generation, inflammation, cell death pathways, neurohormonal mechanisms, advanced glycated end-products accumulation, lipotoxicity, glucotoxicity, and posttranslational modifications in the heart of the diabetic. This review also discusses the impact of antihyperglycemic therapies on the development of heart failure, as well as how current heart failure therapies influence glycemic control in diabetic patients. We also highlight the current knowledge gaps in understanding how diabetes induces heart failure.

Myocardial Interstitial Fibrosis in Nonischemic Heart Disease, Part 3/4: JACC Focus Seminar

Myocardial interstitial fibrosis (MIF) is a histological hallmark of several cardiac diseases that alter myocardial architecture and function and are associated with progression to heart failure. MIF is a diffuse and patchy process, appearing as a combination of interstitial microscars, perivascular collagen fiber deposition, and increased thickness of mysial collagen strands. Although MIF arises mainly because of alterations in fibrillar collagen turnover leading to collagen fiber accumulation, there are also alterations in other nonfibrillar extracellular matrix components, such as fibronectin and matricellular proteins. Furthermore, in addition to an excess of collagen, qualitative changes in collagen fibers also contribute to the detrimental impact of MIF. In this part 3 of a 4-part JACC Focus Seminar, we review the evidence on the complex mechanisms leading to MIF, as well as its contribution to systolic and diastolic cardiac dysfunction and impaired clinical outcomes in patients with nonischemic heart disease.

Establishment of Reference Ranges for Normal Organ Weights in Malaysian Adults at Autopsy

Organ weights are routinely measured during autopsies as a crude screening tool to detect possible organ pathology. In several centers, inclusion of major organ weights indicates whether an autopsy report has achieved its standard of practice, which in turn should be subjected to an audit. Previous studies show statistical variation in organ weights across different populations. Malaysian pathologists have relied on Western data and crude subjective determination in the interpretation of normal organ weights. Hence, the need for a reference range as a guide for pathologists is acute. Organ weights from traumatic deaths between 2004 and 2017 were analyzed in the UKM Medical Centre. Statistical analysis was performed to form reference ranges for normal weights of the brain, heart, lung, liver, spleen, and kidneys. In addition, the data were compared between sexes, races, and body mass index values to determine whether organ weights were affected by these parameters. In this study, reference ranges for organ weights are presented for Malaysian adult men and women.

The Effects of DPP-4 Inhibitors, GLP-1RAs, and SGLT-2/1 Inhibitors on Heart Failure Outcomes in Diabetic Patients With and Without Heart Failure History: Insights From CVOTs and Drug Mechanism

Patients with type 2 diabetes (T2D) have a higher risk of heart failure (HF) than healthy people, and the prognosis of patients with diabetes and current or previous HF is worse than that of patients with only diabetes. We reviewed the HF outcomes in recently published cardiovascular outcome trials (CVOTs) of three new classes of anti-diabetic agents, namely, dipeptidyl peptidase-4 inhibitors (DPP-4is), glucagon-like-peptide 1 receptor agonists (GLP-1RAs), and sodium glucose cotransporter-2 inhibitors (SGLT-2is) or SGLT-2 and SGLT-1 dual inhibitors and divided the patients into two groups based on the history of HF (with or without) and analyzed their risks of HHF based on the receipt of the aforementioned anti-diabetes drug types. Since the follow-up period differed among the trials, we expressed the rate of HHF as events/1,000 person-years to describe the HF outcome. At last we pooled the data and analyzed their different effects and mechanisms on heart failure outcomes. Although DPP-4is did not increase the risk of HHF in T2D patients with a history of HF, they were associated with a significantly higher risk of HHF among patients without history of HF. Some GLP-1RAs reduced the risk of macrovascular events, but none of these drugs reduced the risk of HHF in patients with T2D irrespective of their HF history. It was not clarified whether SGLT-1/2is can improve the prognosis of macrovascular events in patients with T2D, but these drugs reduced the risk of HHF regardless of patients' histories of HF. This information may be useful or referential for the "precise" selection of hyperglycemic medications. Further researches still needed to clarify the mechanisms of these anti-diabetic medications.

Cardiac fibrosis

Myocardial fibrosis, the expansion of the cardiac interstitium through deposition of extracellular matrix proteins, is a common pathophysiologic companion of many different myocardial conditions. Fibrosis may reflect activation of reparative or maladaptive processes. Activated fibroblasts and myofibroblasts are the central cellular effectors in cardiac fibrosis, serving as the main source of matrix proteins. Immune cells, vascular cells and cardiomyocytes may also acquire a fibrogenic phenotype under conditions of stress, activating fibroblast populations. Fibrogenic growth factors (such as transforming growth factor-β and platelet-derived growth factors), cytokines [including tumour necrosis factor-α, interleukin (IL)-1, IL-6, IL-10, and IL-4], and neurohumoral pathways trigger fibrogenic signalling cascades through binding to surface receptors, and activation of downstream signalling cascades. In addition, matricellular macromolecules are deposited in the remodelling myocardium and regulate matrix assembly, while modulating signal transduction cascades and protease or growth factor activity. Cardiac fibroblasts can also sense mechanical stress through mechanosensitive receptors, ion channels and integrins, activating intracellular fibrogenic cascades that contribute to fibrosis in response to pressure overload. Although subpopulations of fibroblast-like cells may exert important protective actions in both reparative and interstitial/perivascular fibrosis, ultimately fibrotic changes perturb systolic and diastolic function, and may play an important role in the pathogenesis of arrhythmias. This review article discusses the molecular mechanisms involved in the pathogenesis of cardiac fibrosis in various myocardial diseases, including myocardial infarction, heart failure with reduced or preserved ejection fraction, genetic cardiomyopathies, and diabetic heart disease. Development of fibrosis-targeting therapies for patients with myocardial diseases will require not only understanding of the functional pluralism of cardiac fibroblasts and dissection of the molecular basis for fibrotic remodelling, but also appreciation of the pathophysiologic heterogeneity of fibrosis-associated myocardial disease.

Left atrial stiffness index as a marker of early target organ damage in hypertension

This study aimed to evaluate left atrial (LA) mechanics using two-dimensional speckle-tracking echocardiography (2DSTE) and investigate their correlations with measures of target organ damage (TOD) in hypertension. We enrolled 42 healthy controls (Group I) and 286 hypertension patients: Group II (n = 79) had an LA volume index (LAVI) <28 ml/m²; Group III (n = 92) had an LAVI ≥28 ml/m²; and Group IV (n = 115) had hypertension with left ventricular hypertrophy (LVH). We measured the following parameters: LA reservoir strain and strain rate (LA_S-S, LA_SR-S), LA conduit strain and strain rate (LA_S-E and LA_SR-E), and LA booster strain and strain rate (LA_S-A and LA_SR-A). The LA stiffness index (LASI) was defined as the ratio of early diastolic transmitral flow velocity/lateral mitral annulus myocardial velocity (E/e') to LA_S-S. We performed correlation and regression analyses of individual TOD with LA phasic functions, the LASI, and cardiovascular risk factors. Our findings showed that there was a trend toward a gradual increase in the LASI from controls to normal LA and enlarged LA patients and finally to hypertrophic LV patients. The LASI was significantly higher in Group III [0.28 (0.20, 0.38)] than in Group I [0.20 (0.16, 0.23)] and Group II [0.22 (0.18, 0.27)] and was the highest in Group IV [0.33 (0.26, 0.43)]. The LA reservoir and conduit function gradually decreased from Group I to Group IV. Multivariate regression analysis revealed that the LASI was independently correlated with individual TOD. In conclusion, abnormal LA mechanics precede LA enlargement and LVH, and an increased LASI can be used as a marker of early TOD in hypertension.

Mechanisms of diabetic cardiomyopathy and potential therapeutic strategies: preclinical and clinical evidence

The pathogenesis and clinical features of diabetic cardiomyopathy have been well-studied in the past decade, but effective approaches to prevent and treat this disease are limited. Diabetic cardiomyopathy occurs as a result of the dysregulated glucose and lipid metabolism associated with diabetes mellitus, which leads to increased oxidative stress and the activation of multiple inflammatory pathways that mediate cellular and extracellular injury, pathological cardiac remodelling, and diastolic and systolic dysfunction. Preclinical studies in animal models of diabetes have identified multiple intracellular pathways involved in the pathogenesis of diabetic cardiomyopathy and potential cardioprotective strategies to prevent and treat the disease, including antifibrotic agents, anti-inflammatory agents and antioxidants. Some of these interventions have been tested in clinical trials and have shown favourable initial results. In this Review, we discuss the mechanisms underlying the development of diabetic cardiomyopathy and heart failure in type 1 and type 2 diabetes mellitus, and we summarize the evidence from preclinical and clinical studies that might provide guidance for the development of targeted strategies. We also highlight some of the novel pharmacological therapeutic strategies for the treatment and prevention of diabetic cardiomyopathy.

Examining the Relationship and Prognostic Implication of Diabetic Status and Extracellular Matrix Expansion by Cardiac Magnetic Resonance

BACKGROUND

Although not fully understood, diabetes mellitus is thought to be associated with cardiac fibrosis and stiffness due to alteration of myocardial extracellular matrix. Newer cardiac magnetic resonance techniques may be able to identify extracellular matrix expansion by measuring extracellular volume fraction (ECV). We used cardiac magnetic resonance to evaluate the association of alteration in the extracellular matrix with diabetic status and its implications on incident heart failure events and all-cause mortality.

METHODS

We studied 442 patients who underwent comprehensive contrast cardiac magnetic resonance to assess cardiac morphology and function, left ventricular replacement fibrosis, and pre-post contrast T1 mapping to quantify ECV. The cohort did not have coexisting pathologies associated with ECV alteration. We categorized our final cohort based on diabetic status using criteria from the American Diabetic Association. Subsequent heart failure hospitalization and all-cause death were ascertained.

RESULTS

Our patients were predominantly white with a median age of 57 with 48% being men. Compared with nondiabetes mellitus, diabetes mellitus was significantly associated with elevated ECV after adjusting for clinical and imaging covariates: β coefficient 1.33 (95% CI, 0.22-2.44); P=0.02. Over a median follow-up of 24.5 (interquartile range, 14.8-33.4) months, 52 deaths and 24 heart failure events occurred. Patients with diabetes mellitus and elevated ECV had the worst outcomes compared with patients with diabetes mellitus and normal ECV or nondiabetics. Elevated ECV remained an independent predictor of outcomes (hazard ratio, 3.31 [95% CI, 1.93-5.67]; P<0.001) after adjusting for covariates.

CONCLUSIONS

Elevated ECV is an independent predictor of mortality among patients with diabetes mellitus and may have an additive effect with diabetes mellitus on outcomes. ECV may represent a novel noninvasive biomarker to evaluate severity of diabetic heart disease.

Predictors of functional improvement in the short term after MitraClip implantation in patients with secondary mitral regurgitation

Background and objectives

MitraClip implantation is an established therapy for secondary mitral regurgitation (MR) in high-risk patients and has shown to improve several important outcome parameters such as functional capacity. Patient selection is both challenging and crucial for achieving therapeutic success. This study investigated baseline predictors of functional improvement as it was quantified by the six-minute walk distance (6MWD) after transcatheter mitral valve repair.

Methods and results

We retrospectively analyzed 79 patients with secondary MR treated with MitraClip implantation at an academic tertiary care center. Before and four weeks after the procedure, all patients underwent comprehensive clinical assessment, six-minute walk tests and echocardiography. 6MWD significantly improved after MitraClip therapy (295 m vs. 265 m, p < 0.001). A linear regression model including seven clinical baseline variables significantly predicted the change in 6MWD (p = 0.002, R² = 0.387). Female gender, diabetes mellitus and arterial hypertension were found to be significant negative predictors of 6MWD improvement. At baseline, female patients had significant higher left ventricular ejection fraction (49% vs. 42%, p = 0.019) and lower 6MWD (240 m vs. 288 m, p = 0.034) than male patients.

Conclusion

MitraClip implantation in secondary MR significantly improves functional capacity in high-risk patients even in the short term of four weeks after the procedure. Female gender, diabetes mellitus and arterial hypertension are baseline predictors of a less favourable functional outcome. While further validation in a larger cohort is recommended, these parameters may improve patient selection for MitraClip therapy.

Basic Mechanisms of Diabetic Heart Disease

Diabetes mellitus predisposes affected individuals to a significant spectrum of cardiovascular complications, one of the most debilitating in terms of prognosis is heart failure. Indeed, the increasing global prevalence of diabetes mellitus and an aging population has given rise to an epidemic of diabetes mellitus-induced heart failure. Despite the significant research attention this phenomenon, termed diabetic cardiomyopathy, has received over several decades, understanding of the full spectrum of potential contributing mechanisms, and their relative contribution to this heart failure phenotype in the specific context of diabetes mellitus, has not yet been fully resolved. Key recent preclinical discoveries that comprise the current state-of-the-art understanding of the basic mechanisms of the complex phenotype, that is, the diabetic heart, form the basis of this review. Abnormalities in each of cardiac metabolism, physiological and pathophysiological signaling, and the mitochondrial compartment, in addition to oxidative stress, inflammation, myocardial cell death pathways, and neurohumoral mechanisms, are addressed. Further, the interactions between each of these contributing mechanisms and how they align to the functional, morphological, and structural impairments that characterize the diabetic heart are considered in light of the clinical context: from the disease burden, its current management in the clinic, and where the knowledge gaps remain. The need for continued interrogation of these mechanisms (both known and those yet to be identified) is essential to not only decipher the how and why of diabetes mellitus-induced heart failure but also to facilitate improved inroads into the clinical management of this pervasive clinical challenge.

Myocardial Changes in Diabetic and Nondiabetic Nonhuman Primates

Diabetic human patients have increased risk of heart failure compared to healthy subjects. The underlying mechanisms for this are not fully understood, and to help develop improved treatment strategies, well-characterized animal models are essential. To investigate cardiac dysfunction in diabetes, this study evaluated myocardial changes in 10 aging rhesus monkeys with and without diabetes. Based on evaluation of plasma glycosylated hemoglobin and glucose, 7 of 10 rhesus macaques had diabetes for a minimum of 11 months, while 3 of 10 were categorized as nondiabetic. A detailed histological examination of formalin-fixed left ventricular myocardial samples was followed by a semiquantitative evaluation of myocardial fibrosis and fat infiltration; digital quantifications of myocardial collagen, lipofuscin, and nuclear area fractions; and measurements of cardiomyocyte diameter. Histological myocardial evaluation revealed the presence of lipofuscin; large nuclei; interstitial, replacement, and vascular fibrosis; adipocyte infiltration; and vacuolar degeneration with atrophy of cardiomyocytes and fibrosis. However, there were no differences between groups for semiquantitative fat infiltration, fibrosis, cardiomyocyte size, collagen, or nuclear and lipofuscin area fraction. Lipofuscin area fraction correlated with plasma insulin, triglyceride, total cholesterol, and high-density lipoprotein cholesterol concentrations. In conclusion, myocardial pathological changes were found in left ventricular myocardium in aged rhesus macaques, independent of the stage of diabetes. The duration of diabetes might have been too short to cause differences between groups.

Characterising an Alternative Murine Model of Diabetic Cardiomyopathy

The increasing burden of heart failure globally can be partly attributed to the increased prevalence of diabetes, and the subsequent development of a distinct form of heart failure known as diabetic cardiomyopathy. Despite this, effective treatment options have remained elusive, due partly to the lack of an experimental model that adequately mimics human disease. In the current study, we combined three consecutive daily injections of low-dose streptozotocin with high-fat diet, in order to recapitulate the long-term complications of diabetes, with a specific focus on the diabetic heart. At 26 weeks of diabetes, several metabolic changes were observed including elevated blood glucose, glycated haemoglobin, plasma insulin and plasma C-peptide. Further analysis of organs commonly affected by diabetes revealed diabetic nephropathy, underlined by renal functional and structural abnormalities, as well as progressive liver damage. In addition, this protocol led to robust left ventricular diastolic dysfunction at 26 weeks with preserved systolic function, a key characteristic of patients with type 2 diabetes-induced cardiomyopathy. These observations corresponded with cardiac structural changes, namely an increase in myocardial fibrosis, as well as activation of several cardiac signalling pathways previously implicated in disease progression. It is hoped that development of an appropriate model will help to understand some the pathophysiological mechanisms underlying the accelerated progression of diabetic complications, leading ultimately to more efficacious treatment options.

Lessons from the Trials for the Desirable Effects of Sodium Glucose Co-Transporter 2 Inhibitors on Diabetic Cardiovascular Events and Renal Dysfunction

Recent large placebo-controlled trials of sodium glucose co-transporter 2 (SGLT2) inhibitors revealed desirable effects on heart failure (HF) and renal dysfunction; however, the mechanisms underlying these effects are unknown. The characteristic changes in the early stage of diabetic cardiomyopathy (DCM) are myocardial and interstitial fibrosis, resulting in diastolic and subsequent systolic dysfunction, which leads to clinical HF. Pericytes are considered to play crucial roles in myocardial and interstitial fibrosis. In both DCM and diabetic retinopathy (DR), microaneurysm formation and a decrease in capillaries occur, triggered by pericyte loss. Furthermore, tubulointerstitial fibrosis develops in early diabetic nephropathy (DN), in which pericytes and mesangial cells are thought to play important roles. Previous reports indicate that pericytes and mesangial cells play key roles in the pathogenesis of DCM, DR and DN. SGLT2 is reported to be functionally expressed in pericytes and mesangial cells, and excessive glucose and Na+ entry through SGLT2 causes cellular dysfunction in a diabetic state. Since SGLT2 inhibitors can attenuate the high glucose-induced dysfunction of pericytes and mesangial cells, the desirable effects of SGLT2 inhibitors on HF and renal dysfunction might be explained by their direct actions on these cells in the heart and kidney microvasculature.

Cardiac risk assessment for end-stage renal disease patients on the renal transplant waiting list

Cardiovascular disease is a leading cause of morbidity and mortality and is becoming more prevalent as the population ages and risk factors increase. This is most apparent in the end-stage renal disease (ESRD) patient population. In part, this is due to cofactors such as diabetes and hypertension commonly predisposing to progressive renal disease, as well as being a direct consequence of having renal failure. Of all major organ failures, kidney failure is the most likely to be managed chronically using renal replacement therapy and, ultimately, transplant. However, lack of transplant organs and a large renal failure cohort means waiting lists are often quite long and may extend to 5-10 years. Due to the cardiac risk factors inherent in patients awaiting transplant, many succumb to cardiac issues while waiting and present an increased per-procedural cardiac risk that extends into the post-transplant period. We aim to review the epidemiology of coronary artery disease in this population and the etiology as it relates to ESRD and its associated co-factors. We also will review the current approaches, recommendations and evidence for management of these patients as it relates to transplant waiting lists before and after the surgery. Recommendations on how to best manage patients in this cohort revolve around the available evidence and are best customized to the institution and the structure of the program. It is not clear whether the revascularization of patients without symptoms and with a good functional status yields any improvement in outcomes. Therefore, each individual case should be considered based on the risk factors, symptoms and functional status, and approached as part of a multi-disciplinary assessment program.

Aortic stenosis and diabetes mellitus: An ominous combination

Aortic stenosis and diabetes mellitus are both progressive diseases which, if left untreated, result in significant morbidity and mortality. There is evidence that the prevalence of diabetes is substantially increased in patients with aortic stenosis and those with diabetes have increased rates of progression from mild to severe aortic stenosis. There are good data supporting the hypothesis that aortic stenosis and diabetes mellitus are associated with diabetes mellitus being detrimental towards the quality of life and survival of patients. Thus, a thorough understanding of the pathogenesis of both of these disease processes and the relationship between them aids in designing appropriate preventive and therapeutic approaches. This review aims to give a comprehensive and up-to-date insight into the influence of diabetes mellitus on patients with degenerative aortic stenosis, as well as the prognosis and therapeutic approach to these patients.

Left ventricular diastolic dysfunction in diabetes mellitus and the therapeutic role of exercise training

Abstract Left ventricular diastolic dysfunction (LVDD) with normal ejection fraction is considered common among people with diabetes mellitus (DM). LVDD is a progressive condition and an independent predictor of mortality in diabetic patients. The etiopathogenesis of LVDD is multifactorial, including diabetes associated comorbidities, such as hypertension, coronary atherosclerosis and obesity, as well as myocardial vascular and metabolic disturbances which lead to diabetic cardiomyopathy. Early stages of LVDD may be detected using echocardiographic techniques. Treatment strategies evolve, based on a better understanding of pathogenic mechanisms, although it is still difficult to efficiently control LVDD evolution. This review synthesizes the main pathophysiological processes and clinical features that characterize DM associated LVDD. Among treatment options, the therapeutic relevance of exercise training programs is underlined. Key words: diabetes mellitus, left ventricular diastolic dysfunction, physical training,

Intermittent hypoxia induces beneficial cardiovascular remodeling in left ventricular function of type 1 diabetic rat

OBJECTIVE

Depressed mechanical activity is a marked complication in diabetics. Hypoxia has properties for novel diagnostic and therapeutic strategies, while intermittent hypoxia (IH) provides early functional and histologic remodeling, including some cardio benefits in early hemodynamic alterations with histologic remodeling and delayed changes in peripheral vasoreactivity. Therefore, we aimed to examine whether IH application presents a cardioprotective effect, via stabilization of hypoxia-inducible factor (HIF) in streptozotocin (STZ)-induced diabetic rat heart.

METHODS

Male 10-week-old Wistar rats were randomly assigned as control group (C), IH group, (STZ)-induced diabetic group (DM) and IH applied DM group (DM+IH). Diabetes duration was kept 6 weeks and IH groups were exposed to hypobaric hypoxia at about 70 kPa (including ~14% PO2; 6 h/day for 6-weeks).

RESULTS

Depressed left ventricular developed pressure (LVDP) and prolonged contraction and relaxation of Langendorff-perfused hearts, as well as increased total oxidative status from streptozotocin (STZ)-induced diabetic rats were markedly prevented with IH application. IH application induced significant increase in protein expression levels of both HIF-1α and vascular endothelial growth factor (VEGF), in both control and diabetic rat hearts, whereas there were significant decreases in the protein levels of prolyl-4 hydroxylase domain enzymes, PHD2, and PHD3 in diabetic hearts. Furthermore, IH application induced marked increases in protein levels of matrix metalloproteinases, MMP-2 and MMP-9 and capillary density in left ventricle of diabetic rats.

CONCLUSION

Overall, we presented how IH application has a beneficial cardiovascular remodeling effect in left ventricular function of diabetic rats, at most, via affecting increased oxidative stress and HIF-VEGF related angiogenesis, providing information on hyperglycemia associated new targets and therapeutic strategies.

Risk Factors Associated With Atrioventricular Block

IMPORTANCE

Pacemaker implantations as a treatment for atrioventricular (AV) block are increasing worldwide. Prevention strategies for AV block are lacking because modifiable risk factors have not yet been identified.

OBJECTIVE

To identify risk factors for AV block in community-dwelling individuals.

DESIGN, SETTING, AND PARTICIPANTS

In this population-based cohort study, data from the Mini-Finland Health Survey, conducted from January 1, 1978, to December 31, 1980, were used to examine demographics, comorbidities, habits, and laboratory and electrocardiographic (ECG) measurements as potential risk factors for incident AV block. Data were ascertained during follow-up from January 1, 1987, through December 31, 2011, using a nationwide registry. A total of 6146 community-dwelling individuals were included in the analysis performed from January 15 through April 3, 2018.

MAIN OUTCOMES AND MEASURES

Incidence of AV block (hospitalization for second- or third-degree AV block).

RESULTS

Among the 6146 participants (3449 [56.1%] women; mean [SD] age, 49.2 [12.9] years), 529 (8.6%) had ECG evidence of conduction disease and 58 (0.9%) experienced a hospitalization with AV block. Older age (hazard ratio [HR] per 5-year increment, 1.34; 95% CI, 1.16-1.54; P < .001), male sex (HR, 2.04; 95% CI, 1.19-3.45; P = .01), a history of myocardial infarction (HR, 3.54; 95% CI, 1.33-9.42; P = .01), and a history of congestive heart failure (HR, 3.33; 95% CI, 1.10-10.09; P = .03) were each independently associated with AV block. Two modifiable risk factors were also independently associated with AV block. Every 10-mm Hg increase in systolic blood pressure was associated with a 22% higher risk (HR, 1.22; 95% CI, 1.10-1.34; P = .005), and every 20-mg/dL increase in fasting glucose level was associated with a 22% higher risk (HR, 1.22; 95% CI, 1.08-1.35; P = .001). Both risk factors remained statistically significant (HR for systolic blood pressure, 1.26 [95% CI, 1.06-1.49; P = .007]; HR for glucose level, 1.22 [95% CI, 1.04-1.43; P = .01]) after adjustment for major adverse coronary events during the follow-up period. In population-attributable risk assessment, an estimated 47% (95% CI, 8%-67%) of AV blocks may have been avoided if all participants exhibited ideal blood pressure and 11% (95% CI, 2%-21%) may have been avoided if all had a normal fasting glucose level.

CONCLUSIONS AND RELEVANCE

In this analysis of data from a population-based cohort study, suboptimal blood pressure and fasting glucose level were associated with AV block. These results suggest that a large proportion of AV blocks are assocated with these risk factors, even after adjusting for other major adverse coronary events.

Molecular Mechanisms Responsible for Diastolic Dysfunction in Diabetes Mellitus Patients

In diabetic patients, cardiomyopathy is an important cause of heart failure, but its pathophysiology has not been completely understood thus far. Myocardial hypertrophy and diastolic dysfunction have been considered the hallmarks of diabetic cardiomyopathy (DCM), while systolic function is affected in the latter stages of the disease. In this article we propose the potential pathophysiological mechanisms responsible for myocardial hypertrophy and increased myocardial stiffness leading to diastolic dysfunction in this specific entity. According to our model, increased myocardial stiffness results from both cellular and extracellular matrix stiffness as well as cell–matrix interactions. Increased intrinsic cardiomyocyte stiffness is probably the most important contributor to myocardial stiffness. It results from the impairment in cardiomyocyte cytoskeleton. Several other mechanisms, specifically affected by diabetes, seem to also be significantly involved in myocardial stiffening, i.e., impairment in the myocardial nitric oxide (NO) pathway, coronary microvascular dysfunction, increased inflammation and oxidative stress, and myocardial sodium glucose cotransporter-2 (SGLT-2)-mediated effects. Better understanding of the complex pathophysiology of DCM suggests the possible value of drugs targeting the listed mechanisms. Antidiabetic drugs, NO-stimulating agents, anti-inflammatory agents, and SGLT-2 inhibitors are emerging as potential treatment options for DCM.

Diabetes and Arrhythmias: Pathophysiology, Mechanisms and Therapeutic Outcomes

The prevalence of diabetes is rapidly increasing and closely associated with cardiovascular morbidity and mortality. While the major cardiovascular complication associated with diabetes is coronary artery disease, it is becoming increasingly apparent that diabetes impacts the electrical conduction system in the heart, resulting in atrial fibrillation, and ventricular arrhythmias. The relationship between diabetes and arrhythmias is complex and multifactorial including autonomic dysfunction, atrial and ventricular remodeling and molecular alterations. This review will provide a comprehensive overview of the link between diabetes and arrhythmias with insight into the common molecular mechanisms, structural alterations and therapeutic outcomes.

Dietary normalization from a fat, fructose and cholesterol-rich diet to chow limits the amount of myocardial collagen in a Göttingen Minipig model of obesity

Background

Dietary interventions have been shown to attenuate some of the myocardial pathological alterations associated with obesity. This study evaluated the effect of dietary normalization from a fat/fructose/cholesterol-rich diet to chow on left ventricular (LV) myocardial fibrosis, fat infiltration and hypertrophy but also the specific influence of obesity, plasma lipids and glucose metabolism markers on heart morphology in a Göttingen Minipig model of obesity.

Methods

Forty castrated male Göttingen Minipigs were assigned to three groups fed either standard minipig chow (SD, n = 8) for 13 months, fat/fructose/cholesterol-rich diet (FFC, n = 16) for 13 months or fat/fructose/cholesterol-rich diet for 7 months and then changed to standard minipig chow for the remaining 6 months (FFC/SD, n = 16). Body weight, body fat percentage, plasma lipids and glucose metabolism markers were evaluated in all three groups after 6–7 months (prior to diet adjustment for FFC/SD) and again before termination. Further, biochemical quantification of myocardial collagen and triglyceride content, semi-quantitative histological evaluation of fibrosis and fat infiltration and quantitative histological analysis of collagen and cardiomyocyte diameter were performed and heart weight was obtained after termination. Group differences were evaluated using Kruskal-Wallis test and Fisher’s exact test for categorical variables. Pearson correlation analysis was performed to test for correlations between myocardial changes and selected explanatory variables. For non-parametric response variables, a Spearman correlation analysis was applied.

Results

Myocardial collagen content quantified biochemically was significantly lower in FFC/SD compared to FFC (P = 0.02). Furthermore, dietary normalization from a fat/fructose/cholesterol-rich diet to chow caused stagnation of body weight and body fat percentage, normalized intravenous glucose tolerance index (K_G) and plasma lipid levels.

Conclusion

Dietary normalization led to lower LV collagen content in obese Göttingen Minipigs. Despite gross obesity and significant deteriorations in glucose and lipid metabolism, only mild myocardial changes were found in this model of obesity and therefore further model optimization is warranted in order to induce more severe myocardial changes before dietary or pharmacological interventions.

Prevalence and distribution of left ventricular diastolic dysfunction in treated patients with long-lasting hypertension

BACKGROUND

Although the presence of sub-clinical left ventricular diastolic dysfunction (LVDD) increases cardiovascular risk, the current ESH/ESC guidelines do not include the presence of this condition in the list of target organ damage or cardiovascular risk charts dedicated to the hypertensive population. Several conditions may predict the LVDD occurrence, however, clustering of these factors with hypertension makes the relationship less clear. Therefore, the aim of this study was to evaluate both the occurrence and the severity of diastolic dysfunction in a large cohort of treated hypertensives.

METHODS

We retrospectively analyzed records of 610 hypertensive participants of the CARE NORTH Study who consented to echocardiography and were free of overt cardiovascular disease. Mean age was 54.0 ± 13.9 years (mean ± SD), BMI 29.7 ± 4.8 kg/m². The exclusion criteria were: established heart failure, LVEF <45%, coronary revascularization, valvular defect, atrial fibrillation, or stroke. The staging of LVDD was based on comprehensive transthoracic echocardiographic measurements.

RESULTS

49.7% percent of the patients had normal diastolic function (38.8% vs. 59.0%, females (F) vs. males (M), respectively; p < .001). Grade 1 LVDD was documented in 24.4% (27.8% and 21.6%; F and M; p = .08) and grade 2 LVDD in 19.3% (24.9% and 14.6%; F and M; p = .001) of the patients. None were diagnosed with grade 3 LVDD. In the logistic regression model, female sex, advancing age, obesity status, established diabetes mellitus, higher 24-hour SBP, and increasing LVMI were identified as the independent variables increasing the odds for the presence of LVDD, whereas blood-lowering therapy attenuated the risk.

CONCLUSIONS

There is an unexpectedly high prevalence of different forms of diastolic dysfunction in treated hypertensive patients who are free of overt cardiovascular disease.

Diabetes-related cardiomyopathy: The sweet story of glucose overload from epidemiology to cellular pathways

Type 2 diabetes (T2D) is a major risk factor for heart failure (HF). Although the number of cases of myocardial infarction in the T2D population has been reduced by 25% over the last 10 years, the incidence of HF is continuously increasing, making it the most worrying diabetes complication. This strongly reinforces the urgent need for innovative therapeutic interventions to prevent cardiac dysfunction in T2D patients. To this end, epidemiological, imaging and animal studies have aimed to highlight the mechanisms involved in the development of diabetic cardiomyopathy. Epidemiological observations clearly show that hyperglycaemia correlates with severity of cardiac dysfunction and mortality in T2D patients. Both animal and cellular studies have demonstrated that, in the context of diabetes, the heart loses its ability to utilize glucose, therefore leading to glucose overload in cardiomyocytes that, in turn, promotes oxidative stress, accumulation of advanced glycation end-products (AGEs) and chronic activation of the hexosamine pathway. These have all been found to activate apoptosis and to alter heart contractility, calcium signalling and mitochondrial function. Although, in the past, tight glycaemic control has failed to improve cardiac function in T2D patients, recent clinical trials have reported cardiovascular benefit with hypoglycaemic antidiabetic drugs of the SGLT2-inhibitor family. This review, based on clinical evidence from mechanistic studies as well as several large clinical trials, covers 15 years of research, and strongly supports the idea that hyperglycaemia and glucose overload play a central role in the pathophysiology of diabetic cardiomyopathy.

Determinants of Left Ventricular Hypertrophy and Diastolic Dysfunction in an HIV Clinical Cohort

OBJECTIVE

The aim of this work was to investigate determinants of structural myocardial abnormalities in persons living with human immunodeficiency virus (PLWH).

METHODS AND RESULTS

We reviewed archived transthoracic echocardiograms (TTEs) performed on PLWH at Duke University Medical Center from 2001 to 2012. The primary outcomes were presence of left ventricular hypertrophy (LVH) or diastolic dysfunction (DD). TTEs for 498 human immunodeficiency virus-infected persons were reviewed (median age 44 years, 38% female, 72% black, 34% with hypertension, 15% with diabetes). Among those with usable images, LVH was detected in 174 of 473 persons (37%) according to LV mass criteria and in 99 of 322 persons (31%) according to American Society of Echocardiography LV mass index criteria. Definite DD was detected in 18 of 224 persons (8%). LVH was more common in PLWH with a CD4 count ≤ 200 cells/mm³ proximal to TTE (adjusted OR 1.68, 95% CI 1.08-2.62), CD4 nadir ≤ 200 cells/mm³ (adjusted OR 1.63, 95% CI 1.04-2.54) and less common in persons with viral suppression (OR 0.46, 95% CI 0.27-0.80). Lower CD4 nadirs (P = .002) and proximal CD4 counts (P = .002) were also associated with DD.

CONCLUSIONS

Persons with a history of advanced human immunodeficiency virus-associated immune suppression are at higher risk of LVH and DD than infected persons with preserved immune function.

Extracellular matrix remodeling and cardiac fibrosis

Cardiac fibrosis, characterized by excessive deposition of extracellular matrix (ECM) proteins in the myocardium, distorts the architecture of the myocardium, facilitates the progression of arrhythmia and cardiac dysfunction, and influences the clinical course and outcome in patients with heart failure. This review describes the composition and homeostasis in normal cardiac interstitial matrix and introduces cellular and molecular mechanisms involved in cardiac fibrosis. We also characterize the ECM alteration in the fibrotic response under diverse cardiac pathological conditions and depict the role of matricellular proteins in the pathogenesis of cardiac fibrosis. Moreover, the diagnosis of cardiac fibrosis based on imaging and biomarker detection and the therapeutic strategies are addressed. Understanding the comprehensive molecules and pathways involved in ECM homeostasis and remodeling may provide important novel potential targets for preventing and treating cardiac fibrosis.