A new method for isolation of cardiac myocytes by percutaneous endomyocardial biopsy

The objective of this study was to demonstrate the feasibility of isolating viable canine cardiac myocytes from percutaneous right ventricular endomyocardial biopsy specimens. Although histologic data can be obtained from percutaneous endomyocardial biopsies, this approach has not been used as a source of viable cells for evaluating pathological conditions. Study of isolated viable myocytes may provide insight into the electrical, biochemical, and physiologic functions of the heart. Using a standard 8F sheath, a 5F bioptome was introduced via the right femoral vein and advanced to the right ventricle, where 85 biopsies were obtained from 8 mongrel dogs. An average of six biopsy specimens were pooled for processing to provide adequate tissue substrate. This resulted in 14 groups of specimens which were then processed to isolate individual myocytes. Viable myocytes were striated, rod-shaped, and excluded trypan blue dye. Nonviable myocytes were rounded, had no cross-striations, and did stain with trypan blue. Partially-injured myocytes contracted spontaneously and had a region of loss of cross-striations. The average number of viable cells recovered per group of pooled specimens was 1.8 x 10(4) (1.8 x 10(3) cells/mg of tissue). The greatest yield of viable myocytes recovered was 8.0 x 10(4), which represented a viability of 90% by trypan blue dye exclusion and morphological criteria. Percutaneous right ventricular endomyocardial biopsy is a novel method for obtaining viable cardiac myocytes. Its feasibility and utility in humans warrant further investigation.