Enzyme prevents fatal heart condition associated with athletes

Scientists at the University of Manchester's Faculty of Life Science have discovered an important enzyme molecule that may prevent fatal cardiac disorders associated with cardiac hypertrophy – the leading cause of sudden cardiac death in young athletes.

Research into fatal heart condition has identified potential therapeutic enzyme

Cardiac hypertrophy is a disease of the heart muscle where a portion of the tissue is thickened without any obvious cause. It is commonly linked to high blood pressure (hypertension) and excessive exercises and results in a shrinking of the heart chamber and a reduction of its blood-pumping volume.

The condition is also associated with fatal cardiac disorders related to irregular heart beats (arrhythmias), leading to millions of deaths worldwide each year, and is perhaps the most well-known cause of sudden cardiac arrest in young sports people.

The researchers used laboratory experiments and computer simulations to show that the enzyme MKK4 is involved in preventing arrhythmias. They believe it does this by modifying another protein, connexin, which forms an electrical bridge between adjacent heart cells to ensure the conduction of electrical activity across the heart as an excitation wave, triggering synchronised mechanical contraction of the heart with a regular heartbeat rhythm.

The multidisciplinary team, writing in The Journal of Biological Chemistry, found that loss of the MKK4 protein disrupts the spatial distribution of connexin, resulting in reduced and non-uniform electrical coupling between heart cells.