High-frequency ultrasonic detection of protein crosslinking in myocardial tissue

The progressive increase in stiffening of the myocardium associated with the aging process and abetted by comorbid conditions such as diabetes may be linked to an excessive number of collagen cross links within the myocardial extra-cellular matrix. The time-evolution of the crosslinking of proteins was monitored with high frequency ultrasound (30-50 MHz). Rats hearts (n=5 each group) were arrested at end-diastole and then insonified fresh within a few minutes of excision in a phosphate buffered solution. The solution was then replaced with a fixative and the tissue was insonified at 30-minute intervals thereafter for 24 hours. A parametric image of the magnitude and frequency dependence of ultrasonic attenuation in heart tissue was constructed at each time point to yield a time-lapse visualization of the process of protein crosslinking.