A genetic abnormality of cardiac myocytes from the blind mutant (RC) chick heart: abnormalities of cardiac structure and choline transport.

A new genetic cardiomyopathy was identified in a blind mutant avian strain. Cardiac myocytes were cultured from 7-day-old chick embryos from Rhode Island Red chickens and from another strain of this species that has been identified to have several abnormalities, the most striking of which is blindness. Cardiac myocytes were maintained in tissue culture. Morphologically, in culture, the cardiac myocyte from the blind mutant strain assumed a spherical shape and showed abnormalities of sarcolemmal membrane compared to control myocytes from heterozygous animals. Choline uptake and metabolism were examined, using [methyl 3H] choline, because it is a sarcolemmal transport process and choline is metabolised to phosphatidylcholine, an important phospholipid for cellular structure and function. Choline uptake through the active transport process was markedly and significantly reduced in the mutant cells compared to control cells, while choline metabolism to phosphatidylcholine was not significantly altered. These results demonstrate a new abnormality of cardiac myocytes, a cardiomyopathy that can be studied in cell culture and one with abnormalities of cellular choline transport.