Comparison of analytical methods for quantitation of isolated porcine hepatocyte yields

As cell-based therapies receive approval for clinical evaluation and use, t he development of reliable methods to quantify cell number and control the dose of therapy delivered is becoming increasingly important. An example is the determination of the number and volume of primary porcine hepatocytes used in an extracorporeal treatment for patients with liver disease. Conven tional cell counting using optical microscopy was compared against two alte rnate methods to quantify isolated porcine hepatocytes: (1) automated cell counting using a commercially available particle characterization instrumen t, and (2) quantitation by cell mass. Methods were compared based on accura cy, precision, specificity, linear range, and ruggedness. The automated met hod delivered substantially improved accuracy, precision, and ruggedness wh en compared to the conventional optical method. It also provided valuable i nformation about the size distribution of cell preparations, which often co ntained clumps of cells, and showed that processing steps such as cryoprese rvation can alter the size characteristics of a cell population. The automa ted method was also faster, and was well suited to use in a commercial manu facturing process. The mass-based method was simple and inexpensive, but su ffered from nonlinearity at low cell concentrations. Automated cell quantit ation using a commercially available particle characterization instrument p roved to be the preferred method for obtaining accurate and consistent porc ine hepatocyte counts in a timely manner.