Source of atrial fibrillation investigated

PHILADELPHIA, Oct. 13 (UPI) -- U.S. scientists say they've found a group of cells that might be part of the cause of atrial fibrillation -- the most common type of abnormal heart beat.

University of Pennsylvania scientists led by Professor Jonathan Epstein and Assistant Professor Vickas Patel said they have identified a population of cells that are like skin pigment-producing cells (melanocytes) located in the atria of the heart and pulmonary veins of mice and humans, uncovering evidence in mice that the cells contribute to atrial fibrillation.

Initial analysis showed the cells express the protein DCT, which is involved in making the skin pigment melanin. Further study, the scientists said, showed DCT-expressing cells in the mouse heart were distinct from both heart muscle cells and skin melanocytes, although they could conduct electrical currents that are important for coordinated contraction of the heart.

Adult mice lacking DCT were susceptible to induced and spontaneous atrial fibrillation and the melanocyte-like cells in their heart exhibited abnormal conduction of electrical currents in vitro.

Mice lacking both melanocyte-like cells in the heart and DCT failed to develop either induced or spontaneous atrial fibrillation, suggesting dysfunctional melanocyte-like cells in the heart might be a trigger of atrial fibrillation in humans.

The study is reported in the Journal of Clinical Investigations.