Distinct Myocardial Targets for Diabetes Therapy in Heart Failure With Preserved or Reduced Ejection Fraction

ACMSD mediated de novo NAD+ biosynthetic impairment in cardiac endothelial cells as a potential therapeutic target for diabetic cardiomyopathy

OBJECT

The highly conserved α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) is the key enzyme that regulates the de novo NAD+ synthesis from tryptophan. NAD+ metabolism in diabetic cardiomyopathy (DCM) was not elucidated yet.

METHODS

Mice were assigned to non-diabetic (NDM) group, streptozocin (STZ)-induced diabetic (DM) group, and nicotinamide (NAM) treated (DM + NAM) group. ACMSD mediated NAD+ metabolism were studied both in mice and patients with diabetes.

RESULTS

NAD+ level was significantly lower in the heart of DM mice than that of the NDM group. Supplementation with NAM could partially increased myocardial capillary density and ameliorated myocardial fibrosis by increasing NAD+ level through salvage pathway. Compared with NDM mice, the expression of ACMSD in myocardial endothelial cells of DM mice was significantly increased. It was further confirmed that in endothelial cells, high glucose promoted the expression of ACMSD. Inhibition of ACMSD could increase de novo NAD+ synthesis and improve endothelial cell function by increasing Sirt1 activity. Targeted mass spectrometry analysis indicated increased ACMSD enzyme activity in diabetic patients, higher ACMSD activity increased risk of heart diastolic dysfunction.

CONCLUSION

In summary, increased expression of ACMSD lead to impaired de novo NAD+ synthesis in diabetic heart. Inhibition of ACMSD could potentially improve DCM.

Exosomes and their derivatives as biomarkers and therapeutic delivery agents for cardiovascular diseases: Situations and challenges

Microvesicles known as exosomes have a diameter of 40 to 160 nm and are derived from small endosomal membranes. Exosomes have attracted increasing attention over the past ten years in part because they are functional vehicles that can deliver a variety of lipids, proteins, and nucleic acids to the target cells they encounter. Because of this function, exosomes may be used for the diagnosis, prognosis and treatment of many diseases. All throughout the world, cardiovascular diseases (CVDs) continue to be a significant cause of death. Because exosomes are mediators of communication between cells, which contribute to many physiological and pathological aspects, they may aid in improving CVD therapies as biomarkers for diagnosing and predicting CVDs. Many studies demonstrated that exosomes are associated with CVDs, such as coronary artery disease, heart failure, cardiomyopathy and atrial fibrillation. Exosomes participate in the progression or inhibition of these diseases mainly through the contents they deliver. However, the application of exosomes in diferent CVDs is not very mature. So further research is needed in this field.

Diabetic microvascular disease in non-classical beds: the hidden impact beyond the retina, the kidney, and the peripheral nerves

Diabetes microangiopathy, a hallmark complication of diabetes, is characterised by structural and functional abnormalities within the intricate network of microvessels beyond well-known and documented target organs, i.e., the retina, kidney, and peripheral nerves. Indeed, an intact microvascular bed is crucial for preserving each organ's specific functions and achieving physiological balance to meet their respective metabolic demands. Therefore, diabetes-related microvascular dysfunction leads to widespread multiorgan consequences in still-overlooked non-traditional target organs such as the brain, the lung, the bone tissue, the skin, the arterial wall, the heart, or the musculoskeletal system. All these organs are vulnerable to the physiopathological mechanisms that cause microvascular damage in diabetes (i.e., hyperglycaemia-induced oxidative stress, inflammation, and endothelial dysfunction) and collectively contribute to abnormalities in the microvessels' structure and function, compromising blood flow and tissue perfusion. However, the microcirculatory networks differ between organs due to variations in haemodynamic, vascular architecture, and affected cells, resulting in a spectrum of clinical presentations. The aim of this review is to focus on the multifaceted nature of microvascular impairment in diabetes through available evidence of specific consequences in often overlooked organs. A better understanding of diabetes microangiopathy in non-target organs provides a broader perspective on the systemic nature of the disease, underscoring the importance of recognising the comprehensive range of complications beyond the classic target sites.

Therapeutic targets of fibrosis: Translational advances and current challenges

In a physiological context, the extracellular matrix (ECM) provides an important scaffold for organs. Dysregulation of ECM in disease conditions, characterised by excess deposition of connective tissue and extracellular matrix in response to a pathological insult, is a key driver of disease progression in multiple organs. The resultant fibrosis is predominantly an irreversible process and directly contributes to, and exacerbates, dysfunction of an affected organ. This is particularly paramount in the kidney, liver, heart and lung. A hybrid Joint Meeting of NC-IUPHAR and British Pharmacological Society was held in Paris and via a webinar in November 2020, when two successive sessions were devoted to translational advances in fibrosis as a therapeutic target. On the upsurge of response to these sessions, the concept of a special themed issue on this topic emerged, and is entitled Translational Advances in Fibrosis as a Therapeutic Target. In this special issue, we seek to provide an up-to-date account of the diverse molecular mechanisms and causal role that fibrosis plays in disease progression (contributing to, and exacerbating, dysfunction of affected organs). Recent developments in the understanding of molecular targets involved in fibrosis, and how their actions can be manipulated therapeutically, are included. LINKED ARTICLES: This article is part of a themed issue on Translational Advances in Fibrosis as a Therapeutic Target. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.22/issuetoc.

Current challenges in the treatment of cardiac fibrosis: Recent insights into the sex-specific differences of glucose-lowering therapies on the diabetic heart: IUPHAR Review 33

A significant cardiac complication of diabetes is cardiomyopathy, a form of ventricular dysfunction that develops independently of coronary artery disease, hypertension and valvular diseases, which may subsequently lead to heart failure. Several structural features underlie the development of diabetic cardiomyopathy and eventual diabetes-induced heart failure. Pathological cardiac fibrosis (interstitial and perivascular), in addition to capillary rarefaction and myocardial apoptosis, are particularly noteworthy. Sex differences in the incidence, development and presentation of diabetes, heart failure and interstitial myocardial fibrosis have been identified. Nevertheless, therapeutics specifically targeting diabetes-associated cardiac fibrosis remain lacking and treatment approaches remain the same regardless of patient sex or the co-morbidities that patients may present. This review addresses the observed anti-fibrotic effects of newer glucose-lowering therapies and traditional cardiovascular disease treatments, in the diabetic myocardium (from both preclinical and clinical contexts). Furthermore, any known sex differences in these treatment effects are also explored. LINKED ARTICLES: This article is part of a themed issue on Translational Advances in Fibrosis as a Therapeutic Target. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.22/issuetoc.

Blood Immune Cell Alterations in Patients with Hypertensive Left Ventricular Hypertrophy and Heart Failure with Preserved Ejection Fraction

(1) Background: Chronic inflammation and fibrosis are key players in cardiac remodeling associated with left ventricular hypertrophy (LVH) and heart failure with a preserved ejection fraction (HFpEF). Monocytes and T-helpers (Th) are involved in both pro-inflammatory and fibrotic processes, while regulatory T-cells (Treg) could be considered to suppress chronic inflammation in the hypertrophied myocardium. We aimed to estimate the relationship between the frequencies of circulating CD4⁺ T-cell and monocyte subpopulations and the variables of left ventricular (LV) diastolic function in patients with LVH depending on the presence of HFpEF. (2) Methods: We enrolled 57 patients with asymptomatic hypertensive LVH (n = 21), or LVH associated with HFpEF (n = 36). A clinical assessment and echocardiographs were analyzed. CD4⁺ Treg, activated Th (Th-act), and monocyte (classical, intermediate, and non-classical) subpopulations were evaluated via direct immunofluorescence and flow cytometry. (3) Results: Patients with HFpEF had a lower Treg/Th-act ratio (p = 0.001). Though asymptomatic patients and patients with HFpEF were comparable in terms of both the total monocyte number and monocyte subsets, there were moderate correlations between intermediate monocyte count and conventional and novel echocardiographic variables of LV diastolic dysfunction in patients with HFpEF. (4) Conclusions: In patients with LVH, the clinical deterioration (transition to HFpEF) and progression of LV diastolic dysfunction are probably associated with T-cell disbalance and an increase in intermediate monocyte counts.

Potential molecular mechanism underlying cardiac fibrosis in diabetes mellitus: a narrative review

BACKGROUND

Diabetes mellitus (DM) is among the most common risk factors for cardiovascular disease in the world with prevalence of more than 500 million population in 2021. Cardiac fibrosis with its complex process has been hypothesized as one of the mechanisms explaining development of heart failure in diabetic patients. Recently, the biomolecular mechanism of cardiac fibrosis in the hyperglycemia setting has been focusing around transforming growth factor β-1 (TGFβ-1) as a major factor. However, there is interplay role of several factors including microRNAs (miRNAs) which acts as a potential regulator of cardiac fibrosis connected with TGFβ-1. In this review, we explored interplay role of several factors including microRNAs which acts as a potential regulator of cardiac fibrosis connected with TGFβ-1 in diabetes mellitus. This narrative review included articles from the PubMed and Science Direct databases published in the last 10 years (2012-2022).

MAIN TEXT

In diabetic patients, excessive activation of myofibroblasts occurs and triggers pro-collagen to convert into mature collagen to fill the cardiac interstitial space resulting in a pathological process of extracellular matrix remodeling. The balance between matrix metalloproteinase (MMP) and its inhibitor (tissue inhibitor of metalloproteinase, TIMP) is crucial in degradation of the extracellular matrix. Diabetes-related cardiac fibrosis is modulated by increasing level of TGF-β1 mediated by cellular components, including cardiomyocyte and non-cardiomyocyte cells involving fibroblasts, vascular pericytes smooth muscle cells, endothelial cells, mast cells, macrophages, and dendritic cells. Several miRNAs such as miR-21, miR-9, miR-29, miR-30d, miR-144, miR-34a, miR-150, miR-320, and miR-378 are upregulated in diabetic cardiomyopathy. TGF-β1, together with inflammatory cytokines, oxidative stress, combined sma and the mothers against decapentaplegic (smad) protein, mitogen-activated protein kinase (MAPK), and microRNAs, is interconnectedly involved in extracellular matrix production and fibrotic response. In this review, we explored interplay role of several factors including microRNAs which acts as a potential regulator of cardiac fibrosis connected with TGFβ-1 in diabetes mellitus.

CONCLUSIONS

Long-term hyperglycemia activates cardiac fibroblast via complex processes involving TGF-β1, miRNA, inflammatory chemokines, oxidative stress, smad, or MAPK pathways. There is increasing evidence of miRNA's roles lately in modulating cardiac fibrosis.

Effects of myocardial sheetlet sliding on left ventricular function

Left ventricle myocardium has a complex micro-architecture, which was revealed to consist of myocyte bundles arranged in a series of laminar sheetlets. Recent imaging studies demonstrated that these sheetlets re-orientated and likely slided over each other during the deformations between systole and diastole, and that sheetlet dynamics were altered during cardiomyopathy. However, the biomechanical effect of sheetlet sliding is not well-understood, which is the focus here. We conducted finite element simulations of the left ventricle (LV) coupled with a windkessel lumped parameter model to study sheetlet sliding, based on cardiac MRI of a healthy human subject, and modifications to account for hypertrophic and dilated geometric changes during cardiomyopathy remodeling. We modeled sheetlet sliding as a reduced shear stiffness in the sheet-normal direction and observed that (1) the diastolic sheetlet orientations must depart from alignment with the LV wall plane in order for sheetlet sliding to have an effect on cardiac function, that (2) sheetlet sliding modestly aided cardiac function of the healthy and dilated hearts, in terms of ejection fraction, stroke volume, and systolic pressure generation, but its effects were amplified during hypertrophic cardiomyopathy and diminished during dilated cardiomyopathy due to both sheetlet angle configuration and geometry, and that (3) where sheetlet sliding aided cardiac function, it increased tissue stresses, particularly in the myofibre direction. We speculate that sheetlet sliding is a tissue architectural adaptation to allow easier deformations of the LV walls so that LV wall stiffness will not hinder function, and to provide a balance between function and tissue stresses. A limitation here is that sheetlet sliding is modeled as a simple reduction in shear stiffness, without consideration of micro-scale sheetlet mechanics and dynamics.

Effects and mechanism of Compound Qidan Formula on rats with HFpEF induced by hypertension and diabetes mellitus based on Ang Ⅱ/TGF-β1/Smads signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Compound Qidan Formula is composed of traditional Chinese herbs and has a good curative effect in the clinical application of cardiovascular diseases such as heart failure. However, its potential molecular mechanisms of action remain highly unknown.

AIM OF THE STUDY

To observe the effect of Compound Qidan Formula on cardiac function in rats with HFpEF induced by hypertension and diabetes mellitus, and to explore its mechanism from Ang Ⅱ/TGF-β1/Smads signaling pathway.

MATERIALS AND METHODS

A total of 50 SPF-grade spontaneously hypertensive rats (SHR) aged 14 weeks, fed with a high-fat and high-sucrose diet for 16 weeks, and after 2 weeks of a high-fat and high-sucrose diet, 1% streptozotocin (25 mg/kg body weight)was injected intraperitoneally to establish a rat model of HFpEF induced by hypertension and diabetes mellitus. After 8 weeks of intragastric administration, the changes in cardiac morphology and function were evaluated by echocardiography after anesthesia; the heart tissue was taken and embedded in paraffin for Masson staining, and the pathomorphological changes of left atrial tissue were observed under the optical microscope; the mRNA transcription levels of Ang Ⅱ, AT1R, TGF-β1, Smad2, Smad3, MMP-9 and TIMP-1in left atrial tissue of rats were detected by RT-PCR; and the protein expressions were detected by Western blot.

RESULTS

Compared with the SHR-DM group, the QD-Low and QD-High groups significantly decreased the left atrial (LA) anteroposterior diameter and interventricular septal thickness (IVST) and improved the peak velocity of mitral valve blood flow in early diastolic period (E), maximum mitral valve blood flow in systolic period (A), mitral ring myocardial movement velocity in early diastolic period (e') and E/e' ratio; the QD-High group significantly improved the E/A ratio, left atrial ejection fraction (LAEF) and left ventricular ejection fraction(LVEF). Masson staining showed that compared with the WKY group, the SHR-DM group had obvious myocardial histomorphological lesions. Compared with the SHR-DM group, the Compound Qidan Formula groups significantly improved cardiomyocyte hypertrophy and disordered arrangement and inhibited myocardial fibrosis; the mRNA expression levels of Ang Ⅱ, AT1R, TGF-β1, Smad2, Smad3, and MMP-9 in myocardial tissue of Compound Qidan Formula groups were significantly decreased, and the mRNA expression level of TIMP-1 was significantly increased. The protein expression levels of Ang Ⅱ, TGF-β1, P-Smad2/3, and MMP-9 were significantly decreased.

CONCLUSION

Compound Qidan Formula, composed of traditional Chinese herbs, can significantly improve cardiac function, improve atrial and ventricular remodeling, and prevent myocardial fibrosis and hypertrophy in rats with HFpEF induced by hypertension and diabetes mellitus. The mechanism may be related to regulating the Ang Ⅱ/TGF-β1/Smad2/3 signaling pathway.

Epidemiology, Pathophysiology, Diagnosis, and Therapy of Heart Failure With Preserved Ejection Fraction in Japan

Heart failure (HF) with preserved ejection fraction (HFpEF) is a global health care problem, with diagnostic difficulty, limited treatment options and high morbidity and mortality rates. The prevalence of HFpEF is increasing because of the aging population and the increasing burden of cardiac and metabolic comorbidities, such as systemic hypertension, diabetes, chronic kidney disease, and obesity. The knowledge base is derived primarily from the United States and Europe, and data from Asian countries, including Japan, remain limited. Given that phenotypic differences may exist between Japanese and Western patients with HFpEF, careful characterization may hold promise to deliver new therapy specific to the Japanese population. In this review, we summarize the current knowledge regarding the epidemiology, pathophysiology and diagnosis of and the potential therapies for HFpEF in Japan.

Is non-alcoholic fatty liver disease a sign of left ventricular diastolic dysfunction in patients with type 2 diabetes mellitus? A systematic review and meta-analysis

Recent studies have associated non-alcoholic fatty liver disease (NAFLD) with impaired cardiac function. However, patients with type 2 diabetes mellitus (T2DM), a high-risk group for left ventricular diastolic dysfunction (LVDD), were not analyzed as an independent study population. A systematic review was conducted to identify all published clinical trials using the PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang databases from inception to September 14, 2022. Observational studies that reported echocardiographic parameters in T2DM patients with NAFLD compared with those without NAFLD were included for further selection. The Agency for Healthcare Research and Quality checklist was used to appraise the study quality. Ten observational studies (all cross-sectional in design) comprising 1800 T2DM patients (1124 with NAFLD, 62.4%) were included. We found that T2DM patients with NAFLD had a significantly lower E/A ratio, higher peak A velocity, higher E/e' ratio, lower e' velocity, greater left atrial maximum volume index, and greater left ventricular mass index than non-NAFLD patients. These findings reinforced the importance of NAFLD being associated with an increased risk of LVDD in the T2DM population, and NAFLD may be a sign of LVDD in patients with T2DM.PROSPERO registration numberCRD42022355844.

Diabetes mellitus is associated with more adverse non-hemodynamic left ventricular remodeling and less recovery in patients with primary aldosteronism

The elevated aldosterone in primary aldosteronism (PA) is associated with increased insulin resistance and prevalence of diabetes mellitus (DM). Both aldosterone excess and DM lead to left ventricular (LV) pathological remodeling. In this study, we investigated the impact of DM on LV non-hemodynamic remodeling in patients with PA. We enrolled 665 PA patients, of whom 112 had DM and 553 did not. Clinical, biochemical, and echocardiographic data were analyzed at baseline and 1 year after adrenalectomy. LV non-hemodynamic remodeling was represented by inappropriate excess left ventricular mass index (ieLVMI), which was defined as the difference between left ventricular mass index (LVMI) and predicted left ventricular mass index (pLVMI). Propensity score matching (PSM) was used with age, sex, systolic, and diastolic blood pressure to adjust for baseline variables. After PSM, the patient characteristics were balanced between the DM and non-DM groups, except for fasting glucose, HbA1c, and lipid profile. A total of 111 DM and 419 non-DM patients were selected for further analysis. Compared to the non-DM group, the DM group had significantly higher ieLVMI and LVMI. After multivariable linear regression analysis, the presence of DM remained a significant predictor of increased ieLVMI. After adrenalectomy, ieLVMI decreased significantly in the non-DM group but not in DM group. The presence of DM in PA patients was associated with more prominent non-hemodynamic LV remodeling and less recovery after adrenalectomy.

Hemoglobin A1c in type 2 diabetes mellitus patients with preserved ejection fraction is an independent predictor of left ventricular myocardial deformation and tissue abnormalities

BACKGROUND

Early detection of subclinical myocardial dysfunction in patients with type 2 diabetes mellitus (T2DM) is essential for preventing heart failure. This study aims to search for predictors of left ventricular (LV) myocardial deformation and tissue abnormalities in T2DM patients with preserved ejection fraction by using CMR T1 mapping and feature tracking.

METHODS

70 patients and 44 sex- and age-matched controls (Cs) were recruited and underwent CMR examination to obtain LV myocardial extracellular volume fraction (ECV) and global longitudinal strain (GLS). The patients were subdivided into three groups, including 19 normotensive T2DM patients (G1), 19 hypertensive T2DM patients (G2) and 32 hypertensive patients (HT). The baseline biochemical indices were collected before CMR examination.

RESULTS

LV ECV in T2DM patients was significantly higher than that in Cs (30.75 ± 3.65% vs. 26.33 ± 2.81%; p < 0.05). LV GLS in T2DM patients reduced compared with that in Cs (-16.51 ± 2.53% vs. -19.66 ± 3.21%, p < 0.001). In the subgroup analysis, ECV in G2 increased compared with that in G1 (31.92 ± 3.05% vs. 29.59 ± 3.90%, p = 0.032) and that in HT, too (31.92 ± 3.05% vs. 29.22 ± 6.58%, p = 0.042). GLS in G2 significantly reduced compared with that in G1 (-15.75 ± 2.29% vs. -17.27 ± 2.57%, p < 0.05) and in HT, too (-15.75 ± 2.29% vs. -17.54 ± 3.097%, p < 0.05). In T2DM group, including both G1 and G2, hemoglobin A1c (HbA1c) can independently forecast the increase in ECV (β = 0.274, p = 0.001) and decrease in GLS (β = 0.383, p = 0.018).

CONCLUSIONS

T2DM patients with preserved ejection fraction show increased ECV but deteriorated GLS, which may be exacerbated by hypertension of these patients. Hemoglobin A1c is an index that can independently predict T2DM patients' LV myocardial deformation and tissue abnormalities.

Emerging concepts in heart failure management and treatment: focus on SGLT2 inhibitors in heart failure with preserved ejection fraction

The role of sodium-glucose cotransporter 2 inhibitors (SLTG2i), developed initially as glucose-lowering agents, has represented a novelty in patients with heart failure (HF) and reduced ejection fraction (HFrEF) since dapagliflozin (DAPA-HF study) and empagliflozin (EMPEROR-Reduced study) were able to reduce morbidity and mortality in this setting regardless of the presence or absence of diabetes. In previous large clinical trials (EMPA-REG OUTCOME study, CANVAS, DECLARE-TIMI 58), SGLT2i have been shown to attenuate HF progression expressed by reducing the risk of HF hospitalizations in patients with type 2 diabetes mellitus mostly without HF at baseline. This benefit was then corroborated with positive results in HF outcomes (cardiovascular mortality and HF hospitalizations) in patients with HF with preserved ejection fraction (HFpEF) in the EMPEROR-Preserved (empagliflozin) and DELIVER (dapagliflozin) trials. Several biological mechanisms apart from the glycosuria are attributed to these agents in this last context, including anti-inflammatory effects, reduction of fibrosis and apoptosis, improvement of myocardial metabolism, mitochondrial function optimization, and oxidative stress protection. Moreover, SGLT2i can also improve ventricular loading conditions by forcing diuresis and natriuresis, and by enhancing vascular and renal function. In addition, SGLT2i can reduce myocardial passive stiffness (diastolic function) by enforcing the phosphorylation of myofilament modulatory proteins. This article provided an overview of the main pathophysiological characteristics of HFpEF and of the diverse mechanisms of action of SGLT2i in this setting. The supporting clinical evidence of SGLT2i in HFpEF (EMPEROR-Preserved and DELIVER trials) is also reviewed. This article is part of the Emerging concepts in heart failure management and treatment Special Issue: https://www.drugsincontext.com/special_issues/emerging-concepts-in-heart-failure-management-and-treatment.

Research Update on the Pathophysiological Mechanisms of Heart Failure with Preserved Ejection Fraction

Heart failure (HF) is a serious clinical syndrome, usually occurs at the advanced stage of various cardiovascular diseases, featured by high mortality and rehospitalization rate. According to left ventricular (LV) ejection fraction (LVEF), HF has been categorized as HF with reduced EF (HFrEF; LVEF<40%), HF with mid-range EF (HFmrEF; LVEF 40-49%), and HF with preserved EF (HFpEF; LVEF ≥50%). HFpEF accounts for about 50% of cases of heart failure and has become the dominant form of heart failure. The mortality of HFpEF is similar to that of HFrEF. There are no welldocumented treatment options that can reduce the morbidity and mortality of HFpEF now. Understanding the underlying pathological mechanisms is essential for the development of novel effective therapy options for HFpEF. In recent years, significant research progress has been achieved on the pathophysiological mechanism of HFpEF. This review aimed to update the research progress on the pathophysiological mechanism of HFpEF.

Duration of Diabetes, Glycemic Control, and Risk of Heart Failure Among Adults With Diabetes: A Cohort Study

CONTEXT

The influences of diabetes duration and glycemic control and their potential interplays on the risk of heart failure (HF) remain unclear.

OBJECTIVE

This work aimed to investigate the association of diabetes duration and glycemic control with the risk of HF.

METHODS

A total of 23 754 individuals with diabetes but without HF during the baseline recruitment of UK Biobank were included in this study. Duration of diabetes was self-reported, and the status of glycemic control was reflected by glycated hemoglobin A1c (HbA1c) levels. Their associations with incident HF were assessed using multivariate Cox models adjusting for traditional risk factors.

RESULTS

Duration of diabetes and HbA1c levels both were positively associated with the risk of HF. The hazard ratios (HRs) (95% CI) for diabetes durations of 5 to less than 10, 10 to less than 15, and 15 years or more were 1.09 (0.97-1.23), 1.13 (0.97-1.30), and 1.32 (1.15-1.53), respectively (vs < 5 years); and the HRs for HbA1c of 53.0 to less than 58.5 mmol/mol (7.0% to < 7.5%), 58.5 to less than 63.9 mmol/mol (7.5% to < 8.0%), and 63.9 mmol/mol or greater (8.0%) were 1.15 (1.02-1.31), 1.07 (0.91-1.26), and 1.46 (1.30-1.65), respectively (vs < 53.0 mmol/mol [7.0%]). Individuals with the longest disease duration (≥ 15 years) and poorer glycemic control (HbA1c  ≥ 63.9 mmol/mol [8.0%]) had a particularly higher risk of HF (P for interaction = .026).

CONCLUSION

The risk of HF among individuals with diabetes increases with a longer duration of diabetes and increasing HbA1c levels. This finding may contribute to the individualized prevention of HF in patients with diabetes if being considered in clinical practices and policy-making.

Preoperative Liver Stiffness is Associated With Hospital Length of Stay After Cardiac Surgery

OBJECTIVES

Risk assessment models for cardiac surgery do not account for the degrees of liver dysfunction. Ultrasound shear-wave elastography measures liver stiffness (LSM), a quantitative measurement related to fibrosis, congestion, and inflammation. The authors hypothesized that preoperative liver stiffness would be associated with hospital length of stay after cardiac surgery.

DESIGN

Prospective observational study.

SETTING

University hospital, single center.

PARTICIPANTS

One hundred five adult patients undergoing nonemergent cardiac surgery.

INTERVENTIONS

Preoperative liver stiffness measured by ultrasound elastography.

MEASUREMENTS AND MAIN RESULTS

The associations were analyzed using linear mixed models, with adjustments for preoperative variables, duration of cardiopulmonary bypass, and type of surgery. Median liver stiffness was 6.4 kPa (range, 4.1-18.6 kPa). The median length of hospital stay was 6 days (range, 3-18 d). Each unit increase in liver stiffness, treated as a continuous variable, was associated with an increase of 0.32 ± 0.10 days in the hospital (p = 0.002). When treated as a categorical variable (<6 kPa, 6-9.4 kPa, and ≥9.5 kPa), LSM ≥9.5 kPa v LSM <6 kPa was associated strongly with an increase in hospital length of stay of 3.25 ± 0.87 days (p = 0.0003).

CONCLUSIONS

A preoperative LSM ≥9.5 kPa was associated with a significantly longer postoperative hospital length of stay. This association appeared independent of preoperative comorbidities commonly associated with coronary disease. Preoperative liver stiffness is a novel risk metric that is associated with the postoperative hospital length of stay after cardiac surgery.

Glycemic Markers and Heart Failure Subtypes: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Although diabetes increases heart failure (HF) risk, it is unclear how various dysglycemia markers (hemoglobin A1C [HbA1C], fasting plasma glucose [FPG], homeostasis model assessment of insulin resistance, and fasting insulin) are associated with HF subtypes (HF with preserved ejection fraction [HFpEF] and HF with reduced ejection fraction [HFrEF]). We assessed the relation of markers of dysglycemia and risks of HFpEF and HFrEF.

METHODS AND RESULTS

We included 6688 adults without prevalent cardiovascular disease who attended the first MESA visit (2000-2002) and were followed for incident hospitalized HF (HFpEF or HFrEF). Association of glycemic markers and status (normoglycemia, prediabetes, diabetes) with HFpEF and HFrEF were evaluated using adjusted Cox models. Over a median follow-up of 14.9 years, there were 356 HF events (145 HFpEF, 173 HFrEF, and 38 indeterminate HF events). Diabetes status conferred higher risks of HFpEF (hazard ratio [HR] 1.85, 95% confidence interval [CI] 1.57-2.68) and HFrEF (HR 2.02, 95% CI 1.38-2.97) compared with normoglycemia. Higher levels of FPG (≥126 mg/dL) and HbA1C (≥6.5%) were associated with similarly higher risks of HFpEF (HR for FPG 1.96, 95% CI 1.21-3.17; HR for HbA1C 2.00, 95% CI 1.20-3.31) and HFrEF (HR for FPG 1.84, 95% CI 1.18-2.88; HR for HbA1C 1.99, 95% CI 1.28-3.09) compared with reference values. Prediabetic range HbA1C (5.7%-6.4%) or FPG (100%-125 mg/dL), homeostasis model assessment of insulin resistance, and fasting insulin were not significantly associated with HFpEF or HFrEF.

CONCLUSIONS

Among community-dwelling individuals, HbA1C and FPG in the diabetes range were each associated with higher risks of HFpEF and HFrEF, with similar magnitudes of their associations.

LAY ABSTRACT

Heart failure (HF) has 2 major subtypes (the heart's inability to pump or to fill up). Diabetes is known to increase HF risk, but its effects and that of markers of high glucose levels (fasting blood glucose and hemoglobin A1C) on the occurrence of HF subtypes remains unknown. Among 6688 adults without known cardiovascular disease followed for nearly 15 years, diabetes conferred significantly higher risks of both HF types, compared with those with normal blood glucose levels. Higher levels of fasting blood glucose and hemoglobin A1C were similarly associated with higher risks of both types of HF.

Gaseous signal molecule SO2 regulates autophagy through PI3K/AKT pathway inhibits cardiomyocyte apoptosis and improves myocardial fibrosis in rats with type II diabetes

Myocardial fibrosis is a key link in the occurrence and development of diabetic cardiomyopathy. Its etiology is complex, and the effect of drugs is not good. Cardiomyocyte apoptosis is an important cause of myocardial fibrosis. The purpose of this study was to investigate the effect of gaseous signal molecule sulfur dioxide (SO₂) on diabetic myocardial fibrosis and its internal regulatory mechanism. Masson and TUNEL staining, Western-blot, transmission electron microscopy, RT-qPCR, immunofluorescence staining, and flow cytometry were used in the study, and the interstitial collagen deposition, autophagy, apoptosis, and changes in phosphatidylinositol 3-kinase (PI3K)/AKT pathways were evaluated from in vivo and in vitro experiments. The results showed that diabetic myocardial fibrosis was accompanied by cardiomyocyte apoptosis and down-regulation of endogenous SO₂-producing enzyme aspartate aminotransferase (AAT)_1/2. However, exogenous SO₂ donors could up-regulate AAT1/2, reduce apoptosis of cardiomyocytes induced by diabetic rats or high glucose, inhibit phosphorylation of PI3K/AKT protein, up-regulate autophagy, and reduce interstitial collagen deposition. In conclusion, the results of this study suggest that the gaseous signal molecule SO₂ can inhibit the PI3K/AKT pathway to promote cytoprotective autophagy and inhibit cardiomyocyte apoptosis to improve myocardial fibrosis in diabetic rats. The results of this study are expected to provide new targets and intervention strategies for the prevention and treatment of diabetic cardiomyopathy.

Sodium houttuyfonate protects against cardiac injury by regulating cardiac energy metabolism in diabetic rats

Diabetic cardiomyopathy is a diabetic complication with complicated pathophysiological changes and pathogenesis and difficult treatment. Sodium houttuyfonate is the adduct of sodium bisulfite and houttuynin, the main volatile component in Houttuynia cordata Thunb, possesses a variety of activities including multiple interventions on inhibiting ventricular remodeling. The study aims to explore effect of sodium houttuyfonate on diabetic myocardial injury and its underlying mechanisms. The diabetes model was established by intraperitoneal injection of streptozotocin at a dose of 85 mg/kg. By intragastric administration for 26 days, sodium houttuyfonate (50 and 100 mg/kg/d) reversed the abnormal serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol and low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio, improved the abnormal levels of serum aspartate aminotransferase and brain natriuretic peptide, reduced electrocardiogram P-R and QRS interval extension, accelerated the heart rate, decreased serum malondialdehyde content, up-regulated the myocardial energy metabolism including elevated the contents of ATP, ADP, total adenine nucleotides and phosphocreatine in myocardium, decreased AMP/ATP ratio, elevated myocardial Ca²⁺-Mg²⁺-ATPase activity, and down-regulated the mRNA expressions of AMP protein activation kinase α₂ (AMPK-α₂) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α). In a conclusion, these results suggest that sodium houttuyfonate can improve cardiac energy metabolism disorder caused by diabetes by increasing cardiac Ca²⁺-Mg²⁺-ATPase activity and regulating AMPK signaling pathway, and then attenuates cardiac injury caused by hyperglycemia. In addition, sodium houttuyfonate also has the effects of anti-oxidation and improving abnormal levels of blood lipid.

Genomic, Proteomic, and Metabolic Comparisons of Small Animal Models of Heart Failure With Preserved Ejection Fraction: A Tale of Mice, Rats, and Cats

Heart failure with preserved ejection fraction (HFpEF) remains a medical anomaly that baffles researchers and physicians alike. The overall phenotypical changes of diastolic function and left ventricular hypertrophy observed in HFpEF are definable; however, the metabolic and molecular alterations that ultimately produce these changes are not well established. Comorbidities such as obesity, hypertension, and diabetes, as well as general aging, play crucial roles in its development and progression. Various animal models have recently been developed to better understand the pathophysiological and metabolic developments in HFpEF and to illuminate novel avenues for pharmacotherapy. These models include multi‐hit rodents and feline aortic constriction animals. Recently, genomic, proteomic, and metabolomic approaches have been used to define altered signaling pathways in the heart associated with HFpEF, including those involved in inflammation, cGMP‐related, Ca²⁺ handling, mitochondrial respiration, and the unfolded protein response in endoplasmic reticulum stress. This article aims to present an overview of what has been learnt by these studies, focusing mainly on the findings in common while highlighting unresolved issues. The knowledge gained from these research models will not simply be of benefit for treating HFpEF but will undoubtedly provide new insights into the mechanisms by which the heart deals with external stresses and how the processes involved can fail.

Exosomal microRNAs miR-30d-5p and miR-126a-5p Are Associated with Heart Failure with Preserved Ejection Fraction in STZ-Induced Type 1 Diabetic Rats

Exosomal microRNAs (EXO-miRNAs) are promising non-invasive diagnostic biomarkers for cardiovascular disease. Heart failure with preserved ejection fraction (HFpEF) is a poorly understood cardiovascular complication of diabetes mellitus (DM). Little is known about whether EXO-miRNAs can be used as biomarkers for HFpEF in DM. We aimed to investigate the relationship between EXO-miRNAs and HFpEF in STZ-induced diabetic rats. We prepared STZ-induced diabetic rats exhibiting a type 1 DM phenotype with low body weight, hyperglycemia, hyperlipidemia and hypoinsulinemia. Histological sections confirmed atrophy and fibrosis of the heart, with collagen accumulation representing diabetic cardiomyopathy. Significant decreases in end-diastolic volume, stroke volume, stroke work, end-systolic elastance and cardiac output indicated impaired cardiac contractility, as well as mRNA conversion of two isoforms of myosin heavy chain (α-MHC and β-MHC) and increased atrial natriuretic factor (ANF) mRNA indicating heart failure, were consistent with the features of HFpEF. In diabetic HFpEF rats, we examined a selected panel of 12 circulating miRNAs associated with HF (miR-1-3p, miR-21-5p, miR-29a-5p, miR-30d-5p, miR-34a-5p, miR-126a-5p, miR-143-3p, miR-145-5p, miR-195-5p, miR-206-3p, miR-320-3p and miR-378-3p). Although they were all expressed at significantly lower levels in the heart compared to non-diabetic controls, only six miRNAs (miR-21-5p, miR-30d-5p, miR-126a-5p, miR-206-3p, miR-320-3p and miR-378-3p) were also reduced in exosomal content, while one miRNA (miR-34a-5p) was upregulated. Similarly, although all miRNAs were correlated with reduced cardiac output as a measure of cardiovascular performance, only three miRNAs (miR-30d-5p, miR-126a-5p and miR-378-3p) were correlated in exosomal content. We found that miR-30d-5p and miR-126a-5p remained consistently correlated with significant reductions in exosomal expression, cardiac expression and cardiac output. Our findings support their release from the heart and association with diabetic HFpEF. We propose that these two EXO-miRNAs may be important for the development of diagnostic tools for diabetic HFpEF.

Patients phenotypes and cardiovascular risk in type 2 diabetes: the Jackson Heart Study

Background

Cardiovascular prognosis related to type 2 diabetes may not be adequately captured by information on comorbid conditions such as obesity and hypertension. To inform the cardiovascular prognosis among diabetic individuals, we conducted phenotyping using a clustering approach based on clinical data, echocardiographic indices and biomarkers.

Methods

We performed a cluster analysis on clinical, biochemical and echocardiographic variables from 529 Blacks with diabetes in the Jackson Heart Study. An association between identified clusters and major adverse cardiovascular events (MACE- composite of coronary heart disease, stroke, heart failure and atrial fibrillation) was assessed using Cox proportional hazards modeling.

Results

Cluster analysis separated individuals with diabetes (68% women, mean age 60 ± 10 years) into three distinct clusters (Clusters 1,2 &3 - with Cluster 3 being a hypertrophic cluster characterized by highest LV mass, levels of brain natriuretic peptide [BNP] and high-sensitivity cardiac troponin-I [hs-cTnI]). After a median 12.1 years, there were 141 cardiovascular events. Compared to Cluster1, Clusters 3 had an increased risk of cardiovascular disease (hazard ratio [HR] 1.60; 95% confidence interval [CI] 1.08, 2.37), while Cluster 2 had a similar risk of outcome (HR 1.11; 95% CI 0.73, 168).

Conclusions

Among Blacks with diabetes, cluster analysis identified three distinct echocardiographic and biomarkers phenotypes, with cluster 3 (high LV mass, high cardiac biomarkers) associated with worse outcomes, thus highlighting the prognostic value of subclinical myocardial dysfunction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01501-z.

Diabetes leading to heart failure and heart failure leading to diabetes: epidemiological and clinical evidence

Type 2 diabetes mellitus (T2DM) is a risk factor that plays a major role in the onset of heart failure (HF) both directly, by impairing cardiac function, and indirectly, through associated diseases such as hypertension, coronary disease, renal dysfunction, obesity, and other metabolic disorders. In a population of HF patients, the presence of T2DM ranged from 20 to 40%, according to the population studied, risk factor characteristics, geographic area, and age, and it is associated with a worse prognosis. Finally, patients with HF, when compared with those without HF, show an increased risk for the onset of T2DM due to several mechanisms that predispose the HF patient to insulin resistance. Despite the epidemiological data confirmed the relationship between T2DM and HF, the exact prevalence of HF in T2DM comes from interventional trials rather than from observational registries aimed to prospectively evaluate the risk of HF occurrence in T2DM population. This review is focused on the vicious cycle linking HF and T2DM, from epidemiological data to prognostic implications.

miR-141-3p regulates saturated fatty acid-induced cardiomyocyte apoptosis through Notch1/PTEN/AKT pathway via targeting PSEN1

It has been reported that miR-141-3p levels are markedly upregulated in the cardiomyocytes of obese rats induced by a high-fat diet. However, the role of miR-141-3p in myocardial lipotoxicity remains elusive. In the present study, the role of miR-141-3p in lipotoxic injury of H9c2 cells induced by palmitic acid (PA) and its possible mechanisms were assessed. The results indicated that miR-141-3p was significantly upregulated in PA-induced cardiomyocytes. miR-141-3p inhibitor enhanced the cell viability, reduced the release of lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), and troponin I (CTN-I), decreased cell apoptosis rate, and repressed the activation of mitochondrial apoptosis pathway in PA-treated H9c2, whereas treatment with miR-141-3p mimics resulted in the opposite effects. Mechanistically, it was further revealed that miR-141-3p could specifically bind to presenilin 1 (PSEN1) 3'UTR, and upregulating miR-141-3p levels reduced the expression of PSEN1, thereby inhibiting the activation of the Notch1/PTEN/AKT pathway. Additionally, inhibition of Notch1/AKT signaling pathway by its inhibitor could abrogate the effect of miR-141-3p on mitochondrial-mediated apoptosis induced by PA. In conclusion, the present study demonstrates that miR-141-3p regulates saturated fatty acid-induced cardiomyocyte apoptosis through Notch1/PTEN/AKT pathway via targeting PSEN1, which gains a new insight into the mechanisms of myocardial lipotoxic injury.

Free L-Lysine and Its Methyl Ester React with Glyoxal and Methylglyoxal in Phosphate Buffer (100 mM, pH 7.4) to Form Nε-Carboxymethyl-Lysine, Nε-Carboxyethyl-Lysine and Nε-Hydroxymethyl-Lysine

Glyoxal (GO) and methylglyoxal (MGO) are highly reactive species formed in carbohydrate metabolism. N^ε-Carboxymethyllysine (CML) and N^ε-carboxyethyllysine (CEL) are considered to be the advanced glycation end-products (AGEs) of L-lysine (Lys) with GO and MGO, respectively. Here, we investigated the reaction of free L-lysine (Lys) with GO and MGO in phosphate buffer (pH 7.4) at 37 °C and 80 °C in detail in the absence of any other chemicals which are widely used to reduce Schiff bases. The concentrations of Lys, GO and MGO used in the experiments were 0.5, 2.5, 5.0, 7.5 and 10 mM. The reaction time ranged between 0 and 240 min. Experiments were performed in triplicate. The concentrations of remaining Lys and of CML and CEL formed in the reaction mixtures were measured by stable-isotope dilution gas chromatography-mass spectrometry (GC-MS). Our experiments showed that CML and CEL were formed at higher concentrations at 80 °C compared to 37 °C. CML was found to be the major reaction product. In mixtures of GO and MGO, MGO inhibited the formation of CML from Lys (5 mM) in a concentration-dependent manner. The highest CML concentration was about 300 µM corresponding to a reaction yield of 6% with respect to Lys. An addition of Lys to GO, MGO and their mixtures resulted in strong reversible decreases in the Lys concentration up to 50%. It is assumed that free Lys reacts rapidly with GO and MGO to form many not yet identified reaction products. Reaction mixtures of Lys and MGO were stronger colored than those of Lys and GO, notably at 80 °C, indicating higher reactivity of MGO towards Lys that leads to polymeric colored MGO species. We have a strong indication of the formation of N^ε-(hydroxymethyl)-lysine (HML) as a novel reaction product of Lys methyl ester with MGO. A mechanism is proposed for the formation of HML from Lys and MGO. This mechanism may explain why Lys and GO do not react to form a related product. Preliminary analyses show that HML is formed at higher concentrations than CEL from Lys methyl ester and MGO. No Schiff bases or their hydroxylic precursors were identified as reaction products. In their reactions with Lys, GO and MGO are likely to act both as chemical oxidants on the terminal aldehyde group to a carboxylic group (i.e., R-CHO to R-COOH) and as chemical reductors on labile Schiff bases (R-CH=N-R to R-CH₂-NH-R) presumably via disproportionation and hydride transfer. Our study shows that free non-proteinic Lys reacts with GO and MGO to form CML, CEL and HML in very low yield. Whether proteinic Lys also reacts with MGO to form HML residues in proteins remains to be investigated. The physiological occurrence and concentration of HML in biological fluids and tissues and its relation to CML and CEL are elusive and warrant further investigations in health and disease. Chemical synthesis and structural characterization of HML are expected to advance and accelerate the scientific research in this topic.

Mean and Variability of Lipid Measurements and Risk for Development of Subclinical Left Ventricular Diastolic Dysfunction

BACKGROUND

Subclinical left ventricular diastolic dysfunction (LVDD) is an emerging consequence of increased insulin resistance, and dyslipidemia is one of the few correctable risk factors of LVDD. This study evaluated the role of mean and visit-to-visit variability of lipid measurements in risk of LVDD in a healthy population.

METHODS

This was a 3.7-year (interquartile range, 2.1 to 4.9) longitudinal cohort study including 2,817 adults (median age 55 years) with left ventricular ejection fraction >50% who underwent an annual or biannual health screening between January 2008 and July 2016. The mean, standard deviation (SD), coefficient of variation (CV), variability independent of the mean (VIM), and average real variability of total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), apolipoprotein B (apoB), non-HDL-C, and triglycerides were obtained from three to six measurements during the 5 years preceding the first echocardiogram.

RESULTS

Among the 2,817 patients, 560 (19.9%) developed LVDD. The mean of no component of lipid measurements was associated with risk of LVDD. CV (hazard ratio [HR], 1.35; 95% confidence interval [CI], 1.10 to 1.67), SD (HR, 1.27; 95% CI, 1.03 to 1.57), and VIM (HR, 1.26; 95% CI, 1.03 to 1.55) of LDL-C and all the variability parameters of apoB were significantly associated with development of LVDD. The association between CV-LDL and risk of LVDD did not have significant interaction with sex, increasing/decreasing trend at baseline, or use of stain and/or lipid-modifying agents.

CONCLUSION

The variability of LDL-C and apoB, rather than their mean, was associated with risk for LVDD.

Fragmented QRS on electrocardiography as a predictor for diastolic cardiac dysfunction in type 2 diabetes

Aims/Introduction

Diastolic cardiac dysfunction in type 2 diabetes (DD2D) is a critical risk of heart failure with preserved ejection fraction. However, there is no established biomarker to detect DD2D. We aimed to investigate the predictive impact of fragmented QRS (fQRS) on electrocardiography on the existence of DD2D.

Materials and Methods

We included in‐hospital patients with type 2 diabetes without heart failure symptoms who were admitted to our institution for glycemic management between November 2017 and April 2021. An fQRS was defined as an additional R′ wave or notching/splitting of the S wave in two contiguous electrocardiography leads. DD2D was diagnosed according to the latest guidelines of the American Society of Echocardiography.

Results

Of 320 participants, 122 patients (38.1%) had fQRS. DD2D was diagnosed in 82 (25.6%). An fQRS was significantly associated with the existence of DD2D (odds ratio 4.37, 95% confidence interval 2.33–8.20; p < 0.0001) adjusted for seven potential confounders. The correlation between DD2D and diabetic microvascular disease was significant only among those with fQRS. Classification and regression tree analysis showed that fQRS was the most relevant optimum split for DD2D.

Conclusions

An fQRS might be a simple and promising predictor of the existence of DD2D. The findings should be validated in a larger‐scale cohort.

Dysregulated Epicardial Adipose Tissue as a Risk Factor and Potential Therapeutic Target of Heart Failure with Preserved Ejection Fraction in Diabetes

Cardiovascular (CV) disease and heart failure (HF) are the leading cause of mortality in type 2 diabetes (T2DM), a metabolic disease which represents a fast-growing health challenge worldwide. Specifically, T2DM induces a cluster of systemic metabolic and non-metabolic signaling which may promote myocardium derangements such as inflammation, fibrosis, and myocyte stiffness, which represent the hallmarks of heart failure with preserved ejection fraction (HFpEF). On the other hand, several observational studies have reported that patients with T2DM have an abnormally enlarged and biologically transformed epicardial adipose tissue (EAT) compared with non-diabetic controls. This expanded EAT not only causes a mechanical constriction of the diastolic filling but is also a source of pro-inflammatory mediators capable of causing inflammation, microcirculatory dysfunction and fibrosis of the underlying myocardium, thus impairing the relaxability of the left ventricle and increasing its filling pressure. In addition to representing a potential CV risk factor, emerging evidence shows that EAT may guide the therapeutic decision in diabetic patients as drugs such as metformin, glucagon-like peptide‑1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 inhibitors (SGLT2-Is), have been associated with attenuation of EAT enlargement.

OUP accepted manuscript

Type 2 diabetes mellitus (T2DM or T2D) is a devastating metabolic abnormality featured by insulin resistance, hyperglycemia, and hyperlipidemia. T2D provokes unique metabolic changes and compromises cardiovascular geometry and function. Meanwhile, T2D increases the overall risk for heart failure (HF) and acts independent of classical risk factors including coronary artery disease, hypertension, and valvular heart diseases. The incidence of HF is extremely high in patients with T2D and is manifested as HF with preserved, reduced, and midrange ejection fraction (HFpEF, HFrEF, and HFmrEF, respectively), all of which significantly worsen the prognosis for T2D. HFpEF is seen in approximately half of the HF cases and is defined as a heterogenous syndrome with discrete phenotypes, particularly in close association with metabolic syndrome. Nonetheless, management of HFpEF in T2D remains unclear, largely due to the poorly defined pathophysiology behind HFpEF. Here, in this review, we will summarize findings from multiple preclinical and clinical studies as well as recent clinical trials, mainly focusing on the pathophysiology, potential mechanisms, and therapies of HFpEF in T2D.

NOX1 mediates metabolic heart disease in mice and is upregulated in monocytes of humans with diastolic dysfunction

AIMS

Microvascular inflammation plays an important role in the pathogenesis of diastolic dysfunction (DD) and metabolic heart disease. NOX1 is expressed in vascular and immune cells and has been implicated in the vascular pathology of metabolic disease. However, its contribution to metabolic heart disease is less understood.

METHODS AND RESULTS

NOX1-deficient mice (KO) and male wild-type (WT) littermates were fed a high-fat high-sucrose diet (HFHS) and injected streptozotocin (75 mg/kg i.p.) or control diet (CTD) and sodium citrate. Despite similar weight gain and increase in fasting blood glucose and insulin, only WT-HFHS but not KO-HFHS mice developed concentric cardiac hypertrophy and elevated left ventricular filling pressure. This was associated with increased endothelial adhesion molecule expression, accumulation of Mac-2-, IL-1β- and NLRP3-positive cells and nitrosative stress in WT-HFHS but not KO-HFHS hearts. Nox1 mRNA was solidly expressed in CD45+ immune cells isolated from healthy mouse hearts, but was negligible in cardiac CD31+ endothelial cells. However, in vitro, Nox1 expression increased in response to LPS in endothelial cells and contributed to LPS-induced upregulation of Icam-1. Nox1 was also upregulated in mouse bone marrow-derived macrophages in response to LPS. In peripheral monocytes from age- and sex-matched symptomatic patients with and without DD, NOX1 was significantly higher in patients with DD compared to those without DD.

CONCLUSIONS

NOX1 mediates endothelial activation and contributes to myocardial inflammation and remodeling in metabolic disease in mice. Given its high expression in monocytes of humans with DD, NOX1 may represent a potential target to mitigate heart disease associated with DD.

TRANSLATIONAL PERSPECTIVE

In their multifactorial pathogenesis, diastolic dysfunction (DD) and heart failure with preserved ejection fraction (HFpEF) still remain poorly understood. They frequently occur in patients with obesity and metabolic syndrome. Microvascular inflammation and dysfunction have recently been recognized as major driving forces. We show that genetic deletion of Nox1 prevents cardiac inflammation, remodeling and dysfunction in metabolic disease in mice and find NOX1 upregulated in peripheral monocytes of patients with DD. These findings add to our understanding how obesity, inflammation and heart disease are linked, which is a prerequisite to find therapeutic strategies beyond the control of co-morbidities in HFpEF.

Impact of diabetes on cardiopulmonary function: the added value of a combined cardiopulmonary and echocardiography stress test

Type 2 diabetes mellitus (T2DM) represents a major health issue worldwide, as patients with T2DM show an excess risk of death for cardiovascular causes, twice as high as the general population. Among the many complications of T2DM, heart failure (HF) deserves special consideration as one of the leading causes of morbidity and reduced life expectancy. T2DM has been associated with different phenotypes of HF, including HF with reduced and preserved ejection fraction. Cardiopulmonary exercise testing (CPET) can evaluate the metabolic and ventilatory alterations related to myocardial dysfunction and/or peripheral impairment, representing a unique tool for the clinician to study the whole HF spectrum. While CPET allows for a thorough evaluation of functional capacity, it cannot directly differentiate central and peripheral determinants of effort intolerance. Combining CPET with imaging techniques could provide even higher accuracy and further insights into the progression of the disease since signs of left ventricular systolic and diastolic dysfunction can be detected during exercise, even in asymptomatic diabetic individuals. This review aims to dissect the alterations in cardiopulmonary function characterising patients with T2DM and HF to improve patient risk stratification.

Intersection Between Diabetes and Heart Failure: Is SGLT2i the "One Stone for Two Birds" Approach?

Purpose of Review

Diabetes mellitus (DM) is a major comorbidity of heart failure (HF). Comparing the similarities and differences in disease characteristics and treatment between the HF patients with and without DM, this review was to investigate whether and how the novel class of sodium-glucose transport protein 2 inhibitors (SGLT2i) would benefit both populations.

Recent Findings

Despite the obviously different clinical profiles, patients of HF with reduced ejection fraction (HFrEF) should be treated the same with guideline directed medical therapy, irrespective of DM status. Upon the mounting evidence that supported its use in diabetic patients at high risk of HF, recent large clinical trials demonstrated that SGLT2i could further reduce HF hospitalization or cardiovascular mortality and improve quality of life in diabetic and non-diabetic HFrEF patients who were optimally managed.

Summary

SGLT2i expands the foundation of HFrEF therapy. Whether it is equally effective in HF with preserved ejection fraction awaits more evidence.

Determinants of the survival benefit associated with statins in patients with acute heart failure

Aims

The benefit of statins in patients with heart failure (HF) remains controversial and the mechanism of action is largely speculative. We investigated the determinants of the survival benefit associated with statins in HF patients.

Methods and results

We enrolled 1680 acute HF patients receiving statins and 2157 patients not receiving statins admitted between 2009 and 2016. The left ventricular (LV) global longitudinal strain (GLS) was assessed as a measure of myocardial contractility. The primary outcome was 5 year all‐cause mortality. Statin therapy was independently associated with improved survival in patients with HF with preserved ejection fraction (HFpEF) [adjusted hazard ratio (HR) 0.781, 95% confidence interval (CI) 0.621–0.981, P = 0.034], but not in those with HF with reduced EF (HFrEF) (adjusted HR 0.881, 95% CI 0.712–1.090, P = 0.244). Mortality reduction associated with statin therapy was significant in patients with ischaemic HF (adjusted HR 0.775, 95% CI 0.607–0.989, P = 0.040), but not in those with non‐ischaemic HF (adjusted HR 0.895, 95% CI 0.734–1.092, P = 0.275). The relative magnitude of survival benefit with statin therapy increased as LV‐EF and LV‐GLS increased, with a steeper dose–response relationship in patients with ischaemic HF. In the subgroup of patients with ischaemic HF, survival benefit with statin therapy was confined to those ≤75 years of age.

Conclusions

Our study suggests that the survival benefit of statins is confined to patients with HFpEF and those with ischaemic HF. Myocardial contractility may modulate the prognostic effects of statins in HF patients, particularly when the aetiology is ischaemic rather than non‐ischaemic.

Chronic low-grade inflammation in heart failure with preserved ejection fraction

Heart failure (HF) with preserved ejection fraction (HFpEF) is currently the predominant form of HF with a dramatic increase in risk with age. Low-grade inflammation, as occurs with aging (termed "inflammaging"), is a common feature of HFpEF pathology. Suppression of proinflammatory pathways has been associated with attenuated HFpEF disease severity and better outcomes. From this perspective, inflammasome signaling plays a central role in mediating chronic inflammation and cardiovascular disease progression. However, the causal link between the inflammasome-immune signaling axis on the age-dependent progression of HFpEF remains conjectural. In this review, we summarize the current understanding of the role of inflammatory pathways in age-dependent cardiac function decline. We will also evaluate recent advances and evidence regarding the inflammatory pathway in the pathophysiology of HFpEF, with special attention to inflammasome signaling.

Does a strict glycemic control during acute coronary syndrome play a cardioprotective effect? Pathophysiology and clinical evidence

A hyperglycemic state, also in non-diabetic subjects, may be associated with acute coronary syndrome (ACS). Aim of this review is to describe the pathophysiologic association between ACS and hyperglycemic state, the protective mechanisms of a tight glycaemic control in ACS on CV outcomes, and the supporting clinical evidence. Several mechanisms may be responsible of a poor CV outcome in subjects with hyperglycemia during ACS. Endothelial NAPDH oxidase-2 (NOX2) activation in response to high glucose alters the balance between Raf/MAPK-dependent vasoconstriction and PI3K/Akt-dependent vasodilation in favour of constriction. Hyperglycaemia induces an overproduction of superoxide by the mitochondrial electron transport chain through different molecular mechanisms. Moreover, hyperglycaemia increases the size of the infarct by causing myocardial cell death through apoptosis and reducing the collateral blood flow. High FFA concentrations lead to toxicity mechanisms in acutely ischemic myocardium. On the other hand, a tight glycaemic control in ACS exerts a cardioprotective action by anti-inflammatory and anti-apoptotic mechanisms, anti-oxidative stress, endothelium protection, FFA reduction, anti-glucotoxic effect, IR and cardiac fuel metabolisms improvement, heart stem cells protection and reduced activation of adrenergic system. Unfortunately, the clinical studies supporting the above pathophysiological background are few and sometimes controversial, more likely due the risk of hypoglycemia linked to the insulin therapy generally used during ACS. Intriguingly, GLP-1 RA and SGLT2i, demonstrated highly effective in the cardiovascular prevention in high-risk subjects without the risk of hypoglycemia, might keep this cardioprotective effect even in acute conditions such as ASC.

Serum Magnesium Is Inversely Associated With Heart Failure, Atrial Fibrillation, and Microvascular Complications in Type 2 Diabetes

OBJECTIVE

We investigated whether serum magnesium (Mg²⁺) was prospectively associated with macro- or microvascular complications and mediated by glycemic control (hemoglobin A_1c [HbA_1c]), in type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

We analyzed in 4,348 participants the association of serum Mg²⁺ with macrovascular disease and mortality (acute myocardial infarction [AMI], coronary heart disease [CHD], heart failure [HF], cerebrovascular accident [CVA], and peripheral arterial disease [PAD]), atrial fibrillation (AF), and microvascular complications (chronic kidney disease [CKD], diabetic retinopathy, and diabetic foot) using Cox regression, adjusted for confounders. Mediation analysis was performed to assess whether HbA_1c mediated these associations.

RESULTS

The average baseline serum Mg²⁺ concentration was 0.80 ± 0.08 mmol/L. During 6.1 years of follow-up, serum Mg²⁺ was inversely associated with major macrovascular, 0.87 (95% CI 0.76; 1.00); HF, 0.76 (95% CI 0.62; 0.93); and AF, 0.59 (95% CI 0.49; 0.72). Serum Mg²⁺ was not associated with AMI, CHD, CVA, and PAD. During 5.1 years of follow-up, serum Mg²⁺ was inversely associated with overall microvascular events, 0.85 (95% CI 0.78; 0.91); 0.89 (95% CI 0.82; 0.96) for CKD, 0.77 (95% CI 0.61; 0.98) for diabetic retinopathy, and 0.85 (95% CI 0.78; 0.92) for diabetic foot. HbA_1c mediated the associations of serum Mg²⁺ with HF, overall microvascular events, diabetic retinopathy, and diabetic foot.

CONCLUSIONS

Serum Mg²⁺ concentration is inversely associated with the risk to develop HF and AF and with the occurrence of CKD, diabetic retinopathy, and foot complications in T2D. Glycemic control partially mediated the association of serum Mg²⁺ with HF and microvascular complications.

Development, validation of a GC-MS method for the simultaneous measurement of amino acids, their PTM metabolites and AGEs in human urine, and application to the bi-ethnic ASOS study with special emphasis to lysine

A gas chromatography-mass spectrometry (GC-MS) method was developed and validated in relevant concentration ranges for the simultaneous measurement of L-lysine (Lys, L) and its N^ε- and N^α-methylated (M), N^ε- and N^α-acetylated (Ac), N^ε-carboxymethylated (CM) and N^ε-carboxyethylated (CE) metabolites in human urine. Analyzed Lys metabolites were the post-translational modification (PTM) products N^ε-mono-, di- and trimethyllsine, N^ε-MML, N^ε-DML, N^ε-TML, respectively, N^α-ML, N^ε-AcL, N^α-AcL, and its advanced glycation end-products (AGEs) N^ε-CML, N^ε-CM-[2,4,4-²H₃]Lys (d₃-CML), N^ε-CEL and furosine. AGEs of arginine (Arg) and cysteine (Cys) were also analyzed. De novo synthesized trideutero-methyl esters (R-COOCD₃) from unlabelled amino acids and derivatives were used as internal standards. Native urine samples (10 µL aliquots) were evaporated to dryness under a stream of nitrogen. Analytes were esterified using 2 M HCl in methanol (60 min, 80 °C) and subsequently amidated by pentafluoropropionic anhydride in ethyl acetate (30 min, 65 °C). The generated methyl ester-pentafluoropropionyl (Me-PFP) derivatives were reconstituted in borate buffer and extracted immediately with toluene. GC-MS analyses were performed by split-less injection of 1-µL aliquots, oven-programmed separation and negative-ion chemical ionization (NICI). Mass spectra were generated in the scan mode (range, m/z 50-1000). Quantification was performed in the selected-ion monitoring (SIM) mode using a dwell time of 50 or 100 ms for each ion. The GC-MS method was suitable for the measurement of Lys and all of its metabolites, except for the quaternary ammonium cation N^ε-TML. The Me-PFP derivatives of Lys, Arg and Cys and its metabolites eluted in the retention time window of 9 to 14 min. The derivatization of N^ε-CML, d₃-CML and N^ε-CEL was accompanied by partial N^ε-decarboxylation and formation of the Me-PFP Lys derivative. The lowest derivatization yield was observed for N^ε-DML, indicating a major role of the N^ε-DML group in Lys derivatization. The GC-MS method enables precise (relative standard deviation, RSD < 20%) and accurate (bias, < ± 20%) simultaneous measurement of 33 analytes in human urine in relevant concentration ranges. We used the method to measure the urinary excretion rates of Lys and its PTM metabolites and AGEs in healthy black (n = 39) and white (n = 41) boys of the Arterial Stiffness in Offspring Study (ASOS). No remarkable differences were found indicating no ethnic-related differences in PTM metabolites and AGEs except for N^ε-monomethyllysine and S-(2-carboxymethylcysteine).

Profile of urinary amino acids and their post-translational modifications (PTM) including advanced glycation end-products (AGEs) of lysine, arginine and cysteine in lean and obese ZSF1 rats

Heart failure with preserved ejection fraction (HFpEF) is associated with high mortality and has an increasing prevalence associated with the demographic change and limited therapeutic options. Underlying mechanisms are largely elusive and need to be explored to identify specific biomarkers and new targets, which mirror disease progression and intervention success. Obese ZSF1 (O-ZSF1) rats are a useful animal model, as they spontaneously develop hypertension, hyperlipidemia and glucose intolerance and finally HFpEF. The urinary profile of amino acids and their metabolites of post-translational modifications (PTM), including the advanced glycation end-products (AGEs) of lysine, arginine and cysteine, are poorly investigated in HFpEF and ZSF1 rats. The aim of the present study was to characterize the status of free amino acids and their metabolites of PTM and glycation in lean ZSF1 (L-ZSF1) and O-ZSF1 rats in urine aiming to find possible effects of glucose on the excretion of native and modified amino acids. In the urine of twelve L-ZSF1 and twelve O-ZFS1 rats collected at the age of 20 weeks, we measured the concentration of native and modified amino acids by reliable previously validated stable-isotope dilution gas chromatography-mass spectrometry (GC–MS) approaches. Serum glucose was 1.39-fold higher in the O-ZSF1 rats, while urinary creatinine concentration was 2.5-fold lower in the O-ZSF1 rats. We observed many differences in urinary amino acids excretion between L-ZSF1 and O-ZSF1 rats. The creatinine-corrected homoarginine excretion was twofold lower in the O-ZSF1 rats. We also observed distinct associations between the concentrations of serum glucose and urinary amino acids including their PTM and AGE metabolites in the L-ZSF1 and O-ZSF1 rats. Our study shows that PTM metabolites and AGEs are consistently lower in the L-ZSF1 than in the O-ZSF1 rats. Serum malondialdehyde (MDA) concentration was higher in the O-ZSF1 rats. These results suggest that hyperglycemia, hyperlipidemia and elevated oxidative stress in the O-ZSF1 rats favor PTM methylation of arginine and lysine and the glycation of lysine and cysteine. The area under the receiver operation characteristic (ROC) curve values were 0.996 for serum glucose, 0.951 for urinary creatinine, 0.939 for serum MDA, 0.885 for N^ε-carboxyethyl-lysine, 0.830 for carboxyethyl-cysteine, and 0.792 for monomethyl-lysine. Non-invasive measurement of methylation and glycation products of arginine, lysine and cysteine residues in proteins in urine of L-ZSF1 and O-ZSF1 rats may be useful in studying pathophysiology and pharmacology of HFpEF.

Mitochondrial Arrest on the Microtubule Highway-A Feature of Heart Failure and Diabetic Cardiomyopathy?

A pathophysiological consequence of both type 1 and 2 diabetes is remodelling of the myocardium leading to the loss of left ventricular pump function and ultimately heart failure (HF). Abnormal cardiac bioenergetics associated with mitochondrial dysfunction occurs in the early stages of HF. Key factors influencing mitochondrial function are the shape, size and organisation of mitochondria within cardiomyocytes, with reports identifying small, fragmented mitochondria in the myocardium of diabetic patients. Cardiac mitochondria are now known to be dynamic organelles (with various functions beyond energy production); however, the mechanisms that underpin their dynamism are complex and links to motility are yet to be fully understood, particularly within the context of HF. This review will consider how the outer mitochondrial membrane protein Miro1 (Rhot1) mediates mitochondrial movement along microtubules via crosstalk with kinesin motors and explore the evidence for molecular level changes in the setting of diabetic cardiomyopathy. As HF and diabetes are recognised inflammatory conditions, with reports of enhanced activation of the NLRP3 inflammasome, we will also consider evidence linking microtubule organisation, inflammation and the association to mitochondrial motility. Diabetes is a global pandemic but with limited treatment options for diabetic cardiomyopathy, therefore we also discuss potential therapeutic approaches to target the mitochondrial-microtubule-inflammatory axis.

Association of sodium-glucose cotransporter-2 inhibitors with outcomes in type 2 diabetes with reduced and preserved left ventricular ejection fraction: Analysis from the CVD-REAL 2 study

This study of real-world data from the Maccabi database in Israel compared the risk of heart failure hospitalization (HHF) or death in patients with type 2 diabetes (T2D) initiating sodium-glucose cotransporter-2 (SGLT2) inhibitors versus other glucose-lowering drugs (OGLDs) according to baseline left ventricular (LV) ejection fraction (EF). After propensity-matching patients by baseline EF there were 10 614 episodes of treatment initiation; 57% had diabetes for >10 years, the mean glycated haemoglobin level was 66 mmol/mol (8.2%), ∼43% had cardiovascular disease, ∼7% had heart failure and ∼ 20% had chronic kidney disease. A total of 2876 patients (∼9%) had reduced EF (<50%). Over a mean follow-up of 1.5 years there were 371 HHFs or deaths, 88 (23.7%) in patients with reduced EF. Initiation of SGLT2 inhibitors versus OGLDs was associated with lower risk of HHF or death overall (hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.46-0.70]; P < 0.001) and in patients with both reduced EF (HR 0.61, 95% CI 0.40-0.93) and preserved EF (HR 0.55, 95% CI 0.43-0.70), with no significant heterogeneity (P_interaction = 0.72). Our findings from real-world clinical practice show that the lower risk of HHF and death associated with use of SGLT2 inhibitors versus OGLDs is consistent in T2D patients with both reduced and preserved EF.

Therapeutic Stalemate in Heart Failure With Preserved Ejection Fraction

The findings of randomized trials of neurohormonal modulation have been neutral in heart failure with preserved ejection fraction and consistently positive in heart failure with reduced ejection. Left ventricular remodeling promotes the development and progression of heart failure with preserved and reduced ejection fraction. However, different stimuli mediate left ventricular remodeling that is commonly concentric in heart failure with preserved ejection fraction and eccentric in heart failure with reduced ejection. The stimuli that promote concentric left ventricular remodeling may account for the neutral findings of neuhormonal modulation in heart failure with preserved ejection fraction. Low‐grade systemic inflammation‐induced microvascular endothelial dysfunction is currently the leading hypothesis behind the development and progression of heart failure with preserved ejection fraction. The hypothesis provided the rationale for several randomized controlled trials that have led to neutral findings. The trials and their limitations are reviewed.

Non-alcoholic fatty liver disease and heart failure with preserved ejection fraction: from pathophysiology to practical issues

The prevalence of non‐alcoholic fatty liver disease (NAFLD) in heart failure (HF) preserved left ventricular ejection fraction (HFpEF) patients could reach 50%. Therefore, NAFLD is considered an emerging risk factor. In 20% of NAFLD patients, the condition progresses to non‐alcoholic steatohepatitis (NASH), the aggressive form of NAFLD characterized by the development of fibrosis in the liver, leading to cirrhosis. The purpose of this review is to provide an overview of the relationships between NAFLD and HFpEF and to discuss its impact in clinical setting. Based on international reports published during the past decade, there is growing evidence that NAFLD is associated with an increased incidence of cardiovascular diseases, including impaired cardiac structure and function, arterial hypertension, endothelial dysfunction, and early carotid atherosclerosis. NAFLD and HFpEF share common risk factors, co‐morbidities, and cardiac outcomes, in favour of a pathophysiological continuum. Currently, NAFLD and NASH are principally managed with non‐specific therapies targeting insulin resistance like sodium‐glucose co‐transporter‐2 inhibitors and liraglutide, which can effectively treat hepatic and cardiac issues. Studies including HFpEF patients are ongoing. Several specific NAFLD‐oriented therapies are currently being developed either alone or as combinations. NAFLD diagnosis is based on a chronic elevation of liver enzymes in a context of metabolic syndrome and insulin resistance, with fibrosis scores being available for clinical practice. In conclusion, identifying HF patients at risk of NAFLD is a critically important issue. As soon as NAFLD is confirmed and its severity determined, patients should be proposed a management focused on symptoms and co‐morbidities.

Network Pharmacology-Based Strategy Reveals the Effects of Hedysarum multijugum Maxim.-Radix Salviae Compound on Oxidative Capacity and Cardiomyocyte Apoptosis in Rats with Diabetic Cardiomyopathy

Objective

To explore the effects of the Hedysarum multijugum Maxim.-Radix Salviae compound (Huangqi-Danshen Compound (HDC)) on oxidative capacity and cardiomyocyte apoptosis in rats with diabetic cardiomyopathy by a network pharmacology-based strategy.

Methods

Traditional Chinese Medicine (TCM)@Taiwan, TCM Systems Pharmacology Database and Analysis Platform (TCMSP), TCM Integrated Database (TCMID), and High-Performance Liquid Chromatography (HPLC) technology were used to obtain and screen HDC's active components, and the PharmMapper database was used to predict HDC human target protein targets. The DCM genes were collected from the GeneCards and OMIM databases, and the network was constructed and analyzed by Cytoscape 3.7.1 and the Database for Annotation, Visualization, and Integrated Discovery (DAVID). Finally, HDC was used to intervene in diabetic cardiomyopathy (DCM) model rats, and important biological processes and signaling pathways were verified using techniques such as immunohistochemistry.

Results

A total of 176 of HDC's active components and 442 potential targets were obtained. The results of network analysis show that HDC can regulate DCM-related biological processes (such as negative regulation of the apoptotic process, response to hypoxia, the steroid hormone-mediated signaling pathway, cellular iron ion homeostasis, and positive regulation of phosphatidylinositol 3-kinase signaling) and signaling pathways (such as the HIF-1 signaling pathway, the estrogen signaling pathway, insulin resistance, the PPAR signaling pathway, the VEGF signaling pathway, and the PI3K-Akt signaling pathway). Animal experiments show that HDC can reduce fasting plasma glucose (FPG), HbA1c, and malondialdehyde (MDA) and increase superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) (P < 0.05). The results of immunohistochemistry showed that HDC can regulate the protein expression of apoptosis-related signaling pathways in DCM rats (P < 0.05).

Conclusion

It was initially revealed that HDC improves DCM through its antiapoptotic and anti-inflammatory effects. HDC may play a therapeutic role by improving cardiomyocyte apoptosis in DCM rats.

Depressed Cardiac Mechanical Energetic Efficiency: A Contributor to Cardiovascular Risk in Common Metabolic Diseases-From Mechanisms to Clinical Applications

Cardiac mechanical energetic efficiency is the ratio of external work (EW) to the total energy consumption. EW performed by the left ventricle (LV) during a single beat is represented by LV stroke work and may be calculated from the pressure-volume loop area (PVLA), while energy consumption corresponds to myocardial oxygen consumption (MVO₂) expressed on a per-beat basis. Classical early human studies estimated total mechanical LV efficiency at 20-30%, whereas the remaining energy is dissipated as heat. Total mechanical efficiency is a joint effect of the efficiency of energy transfer at three sequential stages. The first step, from MVO₂ to adenosine triphosphate (ATP), reflects the yield of oxidative phosphorylation (i.e., phosphate-to-oxygen ratio). The second step, from ATP split to pressure-volume area, represents the proportion of the energy liberated during ATP hydrolysis which is converted to total mechanical energy. Total mechanical energy generated per beat-represented by pressure-volume area-consists of EW (corresponding to PVLA) and potential energy, which is needed to develop tension during isovolumic contraction. The efficiency of the third step of energy transfer, i.e., from pressure-volume area to EW, decreases with depressed LV contractility, increased afterload, more concentric LV geometry with diastolic dysfunction and lower LV preload reserve. As practical assessment of LV efficiency poses methodological problems, De Simone et al. proposed a simple surrogate measure of myocardial efficiency, i.e., mechano-energetic efficiency index (MEEi) calculated from LV stroke volume, heart rate and LV mass. In two independent cohorts, including a large group of hypertensive subjects and a population-based cohort (both free of prevalent cardiovascular disease and with preserved ejection fraction), low MEEi independently predicted composite adverse cardiovascular events and incident heart failure. It was hypothesized that the prognostic ability of low MEEi can result from its association with both metabolic and hemodynamic alterations, i.e., metabolic syndrome components, the degree of insulin resistance, concentric LV geometry, LV diastolic and discrete systolic dysfunction. On the one part, an increased reliance of cardiomyocytes on the oxidation of free fatty acids, typical for insulin-resistant states, is associated with both a lower yield of ATP per oxygen molecule and lesser availability of ATP for contraction, which might decrease energetic efficiency of the first and second step of energy transfer from MVO₂ to EW. On the other part, concentric LV remodeling and LV dysfunction despite preserved ejection fraction can impair the efficiency of the third energy transfer step. In conclusion, the association of low MEEi with adverse cardiovascular outcome might be related to a multi-step impairment of energy transfer from MVO₂ to EW in various clinical settings, including metabolic syndrome, diabetes, hypertension and heart failure. Irrespective of theoretical considerations, MEEi appears an attractive simple tool which couldt improve risk stratification in hypertensive and diabetic patients for primary prevention purposes. Further clinical studies are warranted to estimate the predictive ability of MEEi and its post-treatment changes, especially in patients on novel antidiabetic drugs and subjects with common metabolic diseases and concomitant chronic coronary syndromes, in whom the potential relevance of MEE can be potentiated by myocardial ischemia.

Cellular, mitochondrial and molecular alterations associate with early left ventricular diastolic dysfunction in a porcine model of diabetic metabolic derangement

The prevalence of diabetic metabolic derangement (DMetD) has increased dramatically over the last decades. Although there is increasing evidence that DMetD is associated with cardiac dysfunction, the early DMetD-induced myocardial alterations remain incompletely understood. Here, we studied early DMetD-related cardiac changes in a clinically relevant large animal model. DMetD was established in adult male Göttingen miniswine by streptozotocin injections and a high-fat, high-sugar diet, while control animals remained on normal pig chow. Five months later left ventricular (LV) function was assessed by echocardiography and hemodynamic measurements, followed by comprehensive biochemical, molecular and histological analyses. Robust DMetD developed, evidenced by hyperglycemia, hypercholesterolemia and hypertriglyceridemia. DMetD resulted in altered LV nitroso-redox balance, increased superoxide production—principally due to endothelial nitric oxide synthase (eNOS) uncoupling—reduced nitric oxide (NO) production, alterations in myocardial gene-expression—particularly genes related to glucose and fatty acid metabolism—and mitochondrial dysfunction. These abnormalities were accompanied by increased passive force of isolated cardiomyocytes, and impaired LV diastolic function, evidenced by reduced LV peak untwist velocity and increased E/e′. However, LV weight, volume, collagen content, and cardiomyocyte cross-sectional area were unchanged at this stage of DMetD. In conclusion, DMetD, in a clinically relevant large-animal model results in myocardial oxidative stress, eNOS uncoupling and reduced NO production, together with an altered metabolic gene expression profile and mitochondrial dysfunction. These molecular alterations are associated with stiffening of the cardiomyocytes and early diastolic dysfunction before any structural cardiac remodeling occurs. Therapies should be directed to ameliorate these early DMetD-induced myocardial changes to prevent the development of overt cardiac failure.

Endothelial Dysfunction: A Contributor to Adverse Cardiovascular Remodeling and Heart Failure Development in Type 2 Diabetes beyond Accelerated Atherogenesis

Endothelial dysfunction, associated with depressed nitric oxide (NO) bioavailability, is awell-recognized contributor to both accelerated atherogenesis and microvascular complications intype 2 diabetes (DM). However, growing evidence points to the comorbidities-driven endothelialdysfunction within coronary microvessels as a key player responsible for left ventricular (LV)diastolic dysfunction, restrictive LV remodeling and heart failure with preserved ejection fraction(HFpEF), the most common form of heart failure in DM. In this review we have described: (1)multiple cellular pathways which may link depressed NO bioavailability to LV diastolicdysfunction and hypertrophy; (2) hemodynamic consequences and prognostic effects of restrictiveLV remodeling and combined diastolic and mild systolic LV dysfunction on cardiovascularoutcomes in DM and HFpEF, with a focus on the clinical relevance of endothelial dysfunction; (3)novel therapeutic strategies to improve endothelial function in DM. In summary, beyondassociations with accelerated atherogenesis and microvascular complications, endothelialdysfunction supplements the multiple interwoven pathways affecting cardiomyocytes, endothelialcells and the extracellular matrix with consequent LV dysfunction in DM patients. The associationamongst impaired endothelial function, reduced coronary flow reserve, combined LV diastolic anddiscrete systolic dysfunction, and low LV stroke volume and preload reserve-all of which areadverse outcome predictors-is a dangerous constellation of inter-related abnormalities, underlyingthe development of heart failure. Nevertheless, the relevance of endothelial effects of novel drugsin terms of their ability to attenuate cardiovascular remodeling and delay heart failure onset in DMpatients remains to be investigated.

Skin Autofluorescence as a Predictor of First Heart Failure Hospitalization in Patients With Heart Failure With Preserved Ejection Fraction

Background

An autofluorescence (AF) reader can be used to diagnose skin AF non-invasively by measuring local accumulation of advanced glycation end-products. A number of studies have investigated the relationships between skin AF and cardiovascular disease. However, data regarding the usefulness of skin AF as a predictor of chronic heart failure remain limited. This prospective study aimed to elucidate the usefulness of skin AF as a predictor of first heart failure (HF) hospitalization in patients with HF with preserved ejection fraction (HFpEF).

Methods

A total of 412 outpatients with HFpEF with no history of HF hospitalization were enrolled. Patients were assigned to either the low (group L; skin AF ≤ 2.9 arbitrary units (AU); n = 303) or the high (group H; skin AF ≥ 3.0 AU; n = 109) group according to optimal skin AF cut-off levels determined using receiver operating characteristic curves. Clinical parameters and the usefulness of skin AF as a predictor of first HF hospitalization were evaluated.

Results

The E/e' ratio as a marker of left ventricular diastolic function was significantly higher in group H patients than in group L patients at baseline (group H, 11.8 ± 3.8; group L, 10.6 ± 3.3; P = 0.002). During the 72.7-month follow-up period, 43 HF cases were hospitalized (group L, 15 cases; group H, 28 cases; P < 0.001, log-rank test). Multivariate Cox regression analyses revealed that group H exhibited a significantly higher risk of first HF hospitalization than did group L (hazard ratio, 2.26; 95% confidence interval, 1.21 - 3.52; P = 0.014).

Conclusions

The present study demonstrated that skin AF can predict the risk of first HF hospitalization in patients with HFpEF. Prospective studies, including intervention therapies, are required to validate our observations.

Circulating Cardiac Biomarkers in Diabetes Mellitus: A New Dawn for Risk Stratification-A Narrative Review

The aim of this narrative review is to update the current knowledge on the differential choice of circulating cardiac biomarkers in patients with prediabetes and established type 2 diabetes mellitus (T2DM). There are numerous circulating biomarkers with unconfirmed abilities to predict clinical outcomes in pre-DM and DM individuals; the prognostication ability of the cardiac biomarkers reported here has been established, and they are still being studied. The conventional cardiac biomarkers, such as natriuretic peptides (NPs), soluble suppressor tumorigenisity-2, high-sensitivity circulating cardiac troponins and galectin-3, were useful to ascertain cardiovascular (CV) risk. Each cardiac biomarker has its strengths and weaknesses that affect the price of usage, specificity, sensitivity, predictive value and superiority in face-to-face comparisons. Additionally, there have been confusing reports regarding their abilities to be predictably relevant among patients without known CV disease. The large spectrum of promising cardiac biomarkers (growth/differential factor-15, heart-type fatty acid-binding protein, cardiotrophin-1, carboxy-terminal telopeptide of collagen type 1, apelin and non-coding RNAs) is discussed in the context of predicting CV diseases and events in patients with known prediabetes and T2DM. Various reasons have been critically discussed related to the variable findings regarding biomarker-based prediction of CV risk among patients with metabolic disease. It was found that NPs and hs-cTnT are still the most important tools that have an affordable price as well as high sensitivity and specificity to predict clinical outcomes among patients with pre-DM and DM in routine clinical practice, but other circulating biomarkers need to be carefully investigated in large trials in the future.