Selective cytotoxicity of MIA Pa Ca-2 conditioned medium to acinar cells: a novel approach to reduce acinar cell contaminants in isolated islet preparations from BALB/c mice.

Contamination of acinar cells in islet preparations has been shown to affect islet viability, functionality and yield adversely. Therefore, a strategy which would reduce acinar contamination in islet preparations is much sought. We here demonstrate selective cytotoxicity of conditioned medium (CM) of MIA Pa Ca-2 (human pancreatic carcinoma) cells to acinar cells and suitability of this approach as a simple method of obtaining a pure islet population without affecting their viability and yield. When isolated, islet preparations from BALB/c mice were exposed to conditioned media of MIA Pa Ca-2, acinar cells underwent extensive degeneration to yield 80-85% pure islet population, and islets showed comparable viability to controls not exposed to conditioned media. They also maintained their normal morphology, as assessed by digital image analysis. Islets treated with a conditioned medium also preserved in vitro insulin secretion. Flow cytometric analysis of acinar cells treated with conditioned media revealed accelerated DNA damage (45%), compared to controls (22%). Results emphasize the role of factors secreted by MIA Pa Ca-2 cells in inducing selective toxicity to acinar cells.