Coronary microvascular dysfunction and heart failure with preserved ejection fraction: what are the mechanistic links?

Protective role of the longevity-associated BPIFB4 gene on cardiac microvascular cells and cardiac aging

In recent years, the role of the cardiac microvasculature in modulating the symptoms and disease progression of patients affected by cardiac pathology has been reconsidered. The term cardiac microvascular disease (CMD) describes the set of functional and/or structural alterations of the cardiac microvasculature that reduce the ability of the heart to adequately increase its coronary blood flow to keep up with increased metabolic demand. CMD is involved in the evolution of heart disease of both ischemic and non-ischemic origin as well as in cardiac aging. The primary actors involved in this process are the cells of the stromal compartment, whose nature and biology are now investigated to a new level of detail thanks to single-cell omics studies. Recent studies on the genetics of extreme longevity have identified a polymorphic haplotype variant of the BPIFB4 gene that confers prolonged life span and health span, atheroprotective advantages, and an improved immune response. The aim of this review was to focus on the beneficial effects of the longevity-associated variant (LAV) of BPIFB4 on cardiac microvascular cell biology, providing novel and exciting mechanisms of its action directed against the development or progression of many age-related cardiovascular diseases, thus emphasizing its translational therapeutic potential.

Heart failure and microvascular dysfunction: an in-depth review of mechanisms, diagnostic strategies, and innovative therapies

Microvascular dysfunction (MVD) is increasingly recognized as a critical contributor to the pathogenesis of heart failure (HF), particularly in heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). Coronary microvascular dysfunction (CMD) significantly impacts HFpEF by reducing coronary flow reserve and myocardial perfusion reserve, leading to adverse outcomes such as myocardial ischemia, diastolic dysfunction, and increased risk of major cardiovascular events, including atrial fibrillation. In HFrEF, microvascular impairment is linked to heightened oxidative stress, reduced nitric oxide production, and activation of the renin-angiotensin-aldosterone system, further driving disease progression and contributing to poor prognosis. Advancements in diagnostic techniques, such as positron emission tomography, cardiac magnetic resonance imaging, and biomarker analysis, improve our ability to assess CMD in heart failure patients, enabling earlier diagnosis and risk stratification. Emerging therapies, including sodium-glucose cotransporter-2 inhibitors, angiotensin receptor-neprilysin inhibitors, and endothelial-targeted interventions, enhance microvascular function and improve patient outcomes. The role of personalized medicine is becoming increasingly important, as individualized therapeutic approaches tailored to patient-specific microvascular abnormalities are essential for optimizing treatment effectiveness. This review underscores the pivotal role of MVD in HF. It highlights the urgent need for innovative therapeutic strategies and diagnostic tools to address this complex condition and improve clinical outcomes for HF patients.

Diagnostic and prognostic potential of left atrial strain in cardiovascular disease: a narrative review

Left atrial strain (LAS) was recently introduced as a parameter that reflects on left atrial function. Consequently, changes in LAS can inform the development of cardiovascular diseases, hence providing a window for non-invasive and cost-effective testing of these diseases and their complications at early stages of development, potentially offering a segway towards preventive interventions. LAS has yet to be implemented into standard practice. Therefore, we aimed to synthesize the current evidence on the diagnostic and prognostic potentials of LAS in a variety of cardiovascular diseases. We attempted to elucidate sufficient evidence to support uptake into clinical practice. A systematic search of four databases (Medline, PubMed, Embase, CINAHL) was performed for articles published within the last 5 years, for inclusion in this narrative review. A total of 3921 articles were identified, among which only 43 articles were included. LAS showed diagnostic potential in detecting (1) paroxysmal atrial fibrillation in stroke patients, (2) left atrial appendage dysfunction in patients with nonvalvular atrial fibrillation and heart failure with reduced ejection fraction, and finally (3) diastolic dysfunction in patients with arrhythmias, valvulopathies, acute coronary syndrome, primary arterial hypertension, and heart failure. LAS was also prognostic for the development of (1) atrial fibrillation in hypertensive patients, cardiovascular events in patients with (2) valvular diseases and (3) ischemic heart diseases, and (4) heart failure in patients with and without diastolic dysfunction. This review highlights the potential of LAS in identifying certain cardiac pathologies and their repercussions on patient prognosis, which should prompt courageous integration into the clinical workup while emphasizing areas for future research to guarantee successful and safe implementation into clinical practice.

Healthy longevity-associated protein improves cardiac function in murine models of cardiomyopathy with preserved ejection fraction

AIMS

Aging is influenced by genetic determinants and comorbidities, among which diabetes increases the risk for heart failure with preserved ejection fraction. There is no therapy to prevent heart dysfunction in aging and diabetic individuals. In previous studies, a single administration of the longevity-associated variant (LAV) of the human BPIFB4 gene halted heart decline in older and type 2 diabetic mice. Here, we asked whether orally administered LAV-BPIFB4 protein replicates these benefits.

MATERIALS AND METHODS

In two controlled, randomized studies, 18-month-old male C57BL/6 J mice and 9-week-old C57BLKS/J-Leprdb/Leprdb/Dock7 + [db/db] mice of both sexes underwent baseline echocardiography. They then received a recombinant purified LAV-BPIFB4 protein (3 µg/animal, every three days) or vehicle by gavage. After 30 days, the animals underwent echocardiography, and the hearts were collected post-termination for histology.

RESULTS

All the animals completed the study except one female diabetic mouse, which was culled prematurely because tooth malocclusion caused eating problems. There was no effect of the LAV-BPIFB4 protein on body weight in the two studies or glycosuria in the diabetic study. In aging mice, LAV-BPIFB4 increased myocardial Bpifb4 expression, improving heart contractility and capillarity while reducing perivascular fibrosis and senesce. In male diabetic mice, LAV-BPIFB4 therapy improved systolic function, microvascular density, and senescence, whereas the benefit was limited to systolic function in females.

CONCLUSIONS

This study shows the feasibility and efficacy of a variant protein associated with human longevity in contrasting pivotal risk factors for heart failure in animal models. The diabetic study revealed that sex influences the treatment efficacy.

EASIX (endothelial activation and stress index) predicts mortality in patients with coronary artery disease

BACKGROUND

Coronary interventions reduce morbidity and mortality in patients with acute coronary syndrome. However, the risk of mortality for patients with coronary artery disease (CAD) additionally depends on their systemic endothelial health status. The 'Endothelial Activation and Stress Index' (EASIX) predicts endothelial complications and survival in diverse clinical settings.

OBJECTIVE

We hypothesized that EASIX may predict mortality in patients with CAD.

METHODS

In 1283 patients undergoing coronary catheterization (CC) and having a diagnosis of CAD, EASIX was measured within 52 days (range - 1 year to - 14 days) before CC and correlated with overall survival. In an independent validation cohort of 1934 patients, EASIXval was measured within 174 days (+ 28 days to + 11 years) after CC.

RESULTS

EASIX predicted the risk of mortality after CC (per log2: hazard ratio (HR) 1.29, 95% confidence interval: [1.18-1.41], p < 0.001) in multivariable Cox regression analyses adjusting for age, sex, a high-grade coronary stenosis ≥ 90%, left ventricular ejection fraction, arterial hypertension and diabetes. In the independent cohort, EASIX correlated with EASIXval with rho = 0.7. The long-term predictive value of EASIXval was confirmed (per log2: HR 1.53, [1.42-1.64], p < 0.001) and could be validated by integrated Brier score and concordance index. Pre-established cut-offs (0.88-2.32) associated with increased mortality (cut-off 0.88: HR training: 1.63; HR validation: 1.67, p < 0.0001 and cut-off 2.32: HR training: 3.57; HR validation: 4.65, p < 0.0001).

CONCLUSIONS

We validated EASIX as a potential biomarker to predict death of CAD patients, irrespective of the timing either before or after catheterization.

Beyond the Obstructive Paradigm: Unveiling the Complex Landscape of Nonobstructive Coronary Artery Disease

Traditionally focused on obstructive atherosclerosis, contemporary research indicates that up to 70% of patients undergoing coronary angiography for angina and ischemic symptoms do not exhibit significant stenoses. Nonobstructive coronary artery disease (CAD) has emerged as a prevalent phenotype among these patients. This review emphasizes the emerging understanding that nonobstructive coronary artery disease, encompassing conditions such as ANOCA (Angina with No Obstructive Coronary Artery Disease), INOCA (Ischemia with No Obstructive Coronary Artery Disease), and MINOCA (Myocardial Infarction with No Obstructive Coronary Arteries), represents the most prevalent phenotype in cardiac patients. It delves into the complex pathophysiology underlying these conditions, focusing on microvascular dysfunction and coronary vasoreactivity, which contribute to myocardial ischemia despite the absence of significant coronary obstructions. Additionally, the review critically examines the limitations of current treatments which primarily target obstructive lesions and underscores the necessity for tailored therapies that address the specific microvascular and immunoinflammatory pathways involved in nonobstructive CAD. The main focus of this review is to advocate for a shift in diagnostic and therapeutic strategies to better identify and manage this widely prevalent yet under-recognized subset of CAD.

Microvascular Dysfunction across the Spectrum of Heart Failure Pathology: Pathophysiology, Clinical Features and Therapeutic Implications

Coronary microvascular dysfunction (CMD) plays a crucial role across the spectrum of heart failure (HF) pathology, contributing to disease development, progression, and outcomes. The pathophysiological mechanisms linking CMD to HF are complex and still not completely understood and include chronic inflammation, oxidative stress, and neurohormonal activation. Despite the diagnostic and prognostic relevance in patients with HF, there is no specific therapeutic strategy targeting CMD to date. Moreover, the diagnosis of this clinical condition is challenging. In this review article, we aim to discuss the different clinical pathogenetic mechanisms linking CMD to HF across the different spectra of these diseases, their prognostic relevance, and the possible therapeutic targets along with the remaining knowledge gaps in the field.

The Role of Perivascular Adipose Tissue in the Pathogenesis of Endothelial Dysfunction in Cardiovascular Diseases and Type 2 Diabetes Mellitus

Cardiovascular diseases (CVDs) and type 2 diabetes mellitus (T2DM) are two of the four major chronic non-communicable diseases (NCDs) representing the leading cause of death worldwide. Several studies demonstrate that endothelial dysfunction (ED) plays a central role in the pathogenesis of these chronic diseases. Although it is well known that systemic chronic inflammation and oxidative stress are primarily involved in the development of ED, recent studies have shown that perivascular adipose tissue (PVAT) is implicated in its pathogenesis, also contributing to the progression of atherosclerosis and to insulin resistance (IR). In this review, we describe the relationship between PVAT and ED, and we also analyse the role of PVAT in the pathogenesis of CVDs and T2DM, further assessing its potential therapeutic target with the aim of restoring normal ED and reducing global cardiovascular risk.