Myeloid Fatty Acid Metabolism Activates Neighboring Hematopoietic Stem Cells to Promote Heart Failure With Preserved Ejection Fraction

BACKGROUND

Despite the high morbidity and mortality of heart failure with preserved ejection fraction (HFpEF), treatment options remain limited. The HFpEF syndrome is associated with a high comorbidity burden, including high prevalence of obesity and hypertension. Although inflammation is implicated to play a key role in HFpEF pathophysiology, underlying causal mechanisms remain unclear.

METHODS

Comparing patient samples and animal models, we defined the innate immune response during HFpEF in situ and through flow cytometry and single-cell RNA sequencing. After identifying transcriptional and cell signatures, we implemented a high-fat diet and hypertensive model of HFpEF and tested roles for myeloid and hematopoietic stem cells during HFpEF. Contributions of macrophage metabolism were also evaluated, including through mass spectrometry and carbon labeling. Primary macrophages were studied ex vivo to gain insight into complementary cell-intrinsic mechanisms.

RESULTS

Here we report evidence that patients with cardiometabolic HFpEF exhibit elevated peripheral blood hematopoietic stem cells. This phenotype was conserved across species in a murine mode of high-fat diet and hypertension. Hematopoietic stem cell proliferation was coupled to striking remodeling of the peripheral hematopoietic stem cell niche and expression of the macrophage adhesion molecule Vcam1. This could be partially inhibited by sodium-glucose cotransporter-2 inhibitors and explained by elevated fatty acid metabolism in macrophage mitochondria, which in turn remodeled the Vcam1 promoter to enhance its expression.

CONCLUSIONS

These findings identify a significant new stem cell signature of cardiometabolic HFpEF and support a role for myeloid maladaptive fatty acid metabolism in the promotion of systemic inflammation and cardiac diastolic dysfunction.

Contributions of Inflammation to Cardiometabolic Heart Failure with Preserved Ejection Fraction

The most common form of heart failure is heart failure with preserved ejection fraction (HFpEF). While heterogeneous in origin, the most common form of HFpEF is the cardiometabolic manifestation. Obesity and aging promote systemic inflammation that appears integral to cardiometabolic HFpEF pathophysiology. Accumulation of immune cells within the heart, fueled by an altered metabolome, contribute to cardiac inflammation and fibrosis. In spite of this, broad anti-inflammatory therapy has not shown significant benefit in patient outcomes. Thus, understanding of the nuances to metabolic and age-related inflammation during HFpEF is paramount for more targeted interventions. Here, we review clinical evidence of inflammation in the context of HFpEF and summarize our mechanistic understanding of immunometabolic inflammation, highlighting pathways of therapeutic potential along the way.

Study the relationship between left atrial (LA) volume and left ventricular (LV) diastolic dysfunction and LV hypertrophy: Correlate LA volume with cardiovascular risk factors

Heart failure (HF) with normal ejection fraction - the isolated diastolic heart failure, depicts increasing prevalence and health care burden in recent times. Having less mortality rate compared to systolic heart failure but high morbidity, it is evolving as a major cardiac concern. With increasing clinical use of Left atrial volume (LAV) quantitation in clinical settings, LAV has emerged as an important independent predictor of cardiovascular outcome in HF with normal ejection fraction. This article is intended to review the diastolic and systolic heart failure, their association with left atrial volume, in depth study of Left atrial function dynamics with determinants of various functional and structural changes.

Metabolic inflammation in heart failure with preserved ejection fraction

One in 10 persons in the world aged 40 years and older will develop the syndrome of HFpEF (heart failure with preserved ejection fraction), the most common form of chronic cardiovascular disease for which no effective therapies are currently available. Metabolic disturbance and inflammatory burden contribute importantly to HFpEF pathogenesis. The interplay within these two biological processes is complex; indeed, it is now becoming clear that the notion of metabolic inflammation-metainflammation-must be considered central to HFpEF pathophysiology. Inflammation and metabolism interact over the course of syndrome progression, and likely impact HFpEF treatment and prevention. Here, we discuss evidence in support of a causal, mechanistic role of metainflammation in shaping HFpEF, proposing a framework in which metabolic comorbidities profoundly impact cardiac metabolism and inflammatory pathways in the syndrome.