An in vitro pancreas acinar cell model for testing the modulating effects of caloric restriction and ageing on cellular proliferation and transformation.

Pancreatic acinar cells were isolated for culture from a young (Y) and an old (O) Brown-Norway or Fischer 344 rat fed an ad libitum (AL) or calorically restricted (CR) diet. The cells were cultured and cellular growth rates were determined as a function of passage number. An overall increase in cellular growth rate and transformation frequency with age and/or AL diet relative to youth as well as a decrease with CR diet were concordant with reported responses in vivo. Transformation frequency was measured in Brown-Norway cells and followed the same pattern as the growth response: AL/O > AL/Y = CR/Y > CR/O. The cellular model is shown to fit the general multistage requirements of the carcinogenic process as well as general age and diet characteristics of pancreatic cancer. This pancreatic acinar cell age-diet approach may prove to be a valuable tool for determining mechanisms of exocrine pancreatic carcinogenesis as well as other disease states; it may also be of utility in in vitro gerontological nutritional and pharmacological studies since some of the age and diet determinants of biological effects appear to be segregable. Propensity of cells from an old and/or AL diet animal for faster growth and for cellular transformation are programmed into the cells by the time of their excision from the animal (as late as 14 months), indicating a heritable component in the model or a mechanism that is dependent upon elements that control gene expression.