Methods of isolating cellular products, such as pancreatic islets, may be used in diabetes research and therapeutic transplantation. The methods may involve providing a donor tissue having desired cells and undesired cells, perfusing the donor tissue with a perfusion solution, developing edema during perfusion of the donor tissue to form a swelled tissue, and separating the desired cells from undesired cellular material to obtain a cellular product. The methods may also include disrupting the tissue, and separating the desired cells from undesired cellular material to obtain the cellular product. The methods may result in an increased yield of cellular product that retains sufficient functional integrity to be useful as a transplantation resource.