Multi-omic analysis of the cardiac cellulome defines a vascular contribution to cardiac diastolic dysfunction in obese female mice

Coronary microvascular dysfunction (CMD) is associated with cardiac dysfunction and predictive of cardiac mortality in obesity, especially in females. Clinical data further support that CMD associates with development of heart failure with preserved ejection fraction and that mineralocorticoid receptor (MR) antagonism may be more efficacious in obese female, versus male, HFpEF patients. Accordingly, we examined the impact of smooth muscle cell (SMC)-specific MR deletion on obesity-associated coronary and cardiac diastolic dysfunction in female mice. Obesity was induced in female mice via western diet (WD) feeding alongside littermates fed standard diet. Global MR blockade with spironolactone prevented coronary and cardiac dysfunction in obese females and specific deletion of SMC-MR was sufficient to prevent obesity-associated coronary and cardiac diastolic dysfunction. Cardiac gene expression profiling suggested reduced cardiac inflammation in WD-fed mice with SMC-MR deletion independent of blood pressure, aortic stiffening, and cardiac hypertrophy. Further mechanistic studies utilizing single-cell RNA sequencing of non-cardiomyocyte cell populations revealed novel impacts of SMC-MR deletion on the cardiac cellulome in obese mice. Specifically, WD feeding induced inflammatory gene signatures in non-myocyte populations including B/T cells, macrophages, and endothelium as well as increased coronary VCAM-1 protein expression, independent of cardiac fibrosis, that was prevented by SMC-MR deletion. Further, SMC-MR deletion induced a basal reduction in cardiac mast cells and prevented WD-induced cardiac pro-inflammatory chemokine expression and leukocyte recruitment. These data reveal a central role for SMC-MR signaling in obesity-associated coronary and cardiac dysfunction, thus supporting the emerging paradigm of a vascular origin of cardiac dysfunction in obesity.

Differential impact of severe familial hypercholesterolemia on regional skeletal muscle and organ blood flows during exercise: Effects of PDE5 inhibition

OBJECTIVE

Swine with familial hypercholesterolemia (FH) exhibit attenuated exercise-induced systemic vasodilation that is restored by phosphodiesterase 5 (PDE5) inhibition. Whether the impacts of FH and PDE5 inhibition to impair and restore exercise-induced vasodilation, respectively, results from tissue-specific or generalized effects remains unclear. Thus, we hypothesized that FH induces generalized impairment of skeletal muscle vasodilation that would be alleviated by PDE5 inhibition.

METHODS

Systemic vascular responses to exercise were assessed in chronically instrumented normal and FH swine before and after PDE5 inhibition with EMD360527. Skeletal muscle and organ blood flows and conductances were determined via the microsphere technique.

RESULTS

As previously reported, vs normal swine, FH swine have pronounced elevation of total cholesterol and impaired exercise-induced vasodilation that is restored by PDE5 inhibition. Blood flows to several, not all, skeletal muscle vascular beds were severely impaired by FH associated with reduced blood flow to many visceral organs. PDE5 inhibition differentially impacted skeletal muscle and organ blood flows in normal and FH swine.

CONCLUSIONS

These data indicate that FH induces regional, not generalized, vasomotor dysfunction and that FH and normal swine exhibit unique tissue blood flow responses to PDE5 inhibition thereby adding to accumulating evidence of vascular bed-specific dysfunction in co-morbid conditions.