The relatively reduced percentage of positive differentiation events seen in ocular ASC cell lines may have a number of different causes. Three likely explanations may account for these differences. First, a coisolated, more rapidly proliferative, but nonstem cell population eventually overtakes the stem cell cultures by the time the differentiation experiments are performed. Second, the ASCs isolated from these fat depots are not as responsive to the differentiation media used for stem cells derived from other depots in the body. Third, the difference results from both coisolate contaminating cells