Wearable technologies such as smartwatches require only a quick glance
at the wrist to check one’s heart rate and rhythm. While these devices provide wearers with lots
of information about their heart’s output, additional methods are required to
examine the cells responsible for the functioning of the heart. A group of researchers have recently engineered heart tissue out of stems cells to do just that. These engineered cells allow scientists to
examine mechanisms underlying tachycardia-induced cardiomyopathy which is impairment
in the functioning of the heart that can occur secondary to a chronic rapid heart
rate. While the observation that rapid and protracted heart pacing can lead to heart
failure was first identified in the 1960s the precise mechanisms responsible
for the contractile dysfunction have not been well understood. Scientists at Stanford University found that
when the engineered heart cells were induced to create tachycardia, metabolic rewiring of heart cells drove
contractile dysfunction by promoting tissue hypoxia (lack of oxygen), elevated
glucose utilization and the suppression of oxidative phosphorylation. Not only
did this study help understand the root causes of the pathophysiology, but the
researchers found that by providing damaged cells with molecules believed to
play a role in the metabolic dysfunction (e.g., NAD, a molecule that supports
energy reactions) resulted in the cells recovering most of their original
function. Therefore, because prolonged tachycardia can reduce the heart’s
ability to pump blood sufficiently, understanding how metabolic rewiring occurs
opens up opportunities for novel therapeutic interventions.