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 affec t islet viability, functionality and yield adversely. Therefore, a strategy which would reduce acinar contamination in islet preparations is much soug ht. We here demonstrate selective cytotoxicity of conditioned medium (CM) o f MIA Pa Ca-2 (human pancreatic carcinoma) cells to acinar cells and suitab ility of this approach as a simple method of obtaining a pure islet populat ion without affecting their viability and yield. When isolated, islet prepa rations 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 po pulation, and islets showed comparable viability to controls not exposed to conditioned media. They also maintained their normal morphology, as assess ed by digital image analysis. Islets treated with a conditioned medium also preserved in vitro insulin secretion. Flow cytometric analysis of acinar c ells 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.