A Non-Invasive Method for Measuring Contractility in Cardiocytes

We are developing a noninvasive procedure for measuring contractile responses of both adult and neonatal mammalian cardiocytes. This method can be employed to quantify pharmacological effects of drugs on myocytes. Methods for quantifying neonatal cell contraction reported in the literature have required the use of elaborate equipment such as a proximity detector or an atomic force microscope (to measure the increase in cell elevation as a cardiocyte contracts), and typically interfere with simultaneous optical recording of cell signals. Such contraction quantification methods are expensive due to the equipment needed. Our approach to contractile measurement is being developed with the goal to be a practical and relatively inexpensive method. Our approach uses two different image processing procedures that allow us to produce contractility records of both adult and neonatal cardiocytes. In our first procedure we analyze neonatal myocytes. Contraction curves generated from neonatal cells with our new method exhibit a very similar profile and time course to those produced by more sophisticated and expensive methods [11, 15]. Our second image processing procedure is an application that allows measurement of the adult cardiocytes area in each frame. Application of our two dimensional quantification technique to the study of adult cardiocytes produces contraction vs. time records virtually identical in time course and shape to records obtained from traditional one dimensional, cell boundary tracking procedures [12]. The contractility graphs created by the two image processing procedures are consistent with the expected results and graphs resulting from past studies performed on myocytes [10]. This new non-invasive approach to contractile quantification will be useful in the analysis of the myocyte contractile dynamics in the presence of drugs.