American Heart Association

Progenitor cells are decreased in heart failure and specific to HF type

Contributor: Mat Bull

Do progenitor cells matter for patients with HF? First, what is a progenitor cell? A progenitor cell is a stem cell that has potential to differentiate into multiple different cell types. Progenitor cells are classified by cluster of differentiation surface markers, which act as receptors and ligands to their target tissue. CD34+ progenitor cells have been shown to play a role in vascular and myocardial regeneration and in this article are shown to be an important biomarker in heart failure.

Impaired relaxation and elevated intracellular Ca2+ in contracting myocardium of hypertensive heart disease and HFpEF

Contributor: Steven Stroud

Relaxing can be hard in hypertensive heart disease (HHD). Specifically, for the stiff ventricle destined for HFpEF. Is it a problem with relaxation of myocytes, or is it due to stiffening from fibrosis?

Entry of Ca2+ into the myocyte begins a flood of stored Ca2+, stimulating contraction. The cell can relax only when this Ca2+ is taken away from the contractile apparatus. Along with SERCA and phospholamban, the sarcolemmal Na+/Ca2+ exchanger (NCX) handles this important duty.

Rapid decline in high energy phosphate leads to exercise intolerance in HF patients

Contributor: Steven Stroud

Exercise intolerance is a hallmark of HF. We tend to blame the weak heart for not delivering enough oxygen to exercising muscles, but this is wrong.

Muscles without oxygen are hypoxic. This could happen because of poor cardiac output or because the skeletal muscle cells are not handling oxygen well. In other words, does low cardiac output cause fatigability or are there differences in skeletal muscle energetics in HF?