Evaluation of monolayer, liquid, gelfoam sponge and artificial capillary culture systems for the study of hematopoiesis

This study evaluated the usefulness of a matrix culture system, the artificial capillary culture system, for the growth of hematopoietic cells, the maintenance of CFU(s) and the collection of GM-CSF. The system was compared to monolayer, gelfoam sponge and Dexter liquid cultures. Monolayer cultures of adherent lymphohematopoietic stromal cells were prepared from bone fragments, whole bone marrow (Dexter system), spleen, fetal liver and thymus preparations. Morphologically, all the adherent cell populations were similar and tended to accumulate macrophages. Despite these morphological similarities, the ability of bone marrow adherent cell monolayers to maintain CFU(s) early in the culture period was significantly greater than adherent cells from other sources. Low but significant levels of GM-CSF were detected by bioassay in the supernatants of all but bone marrow adherent cell cultures. However, adherent cells selected from whole marrow cultures by differential trypsinization contained bioassayable levels of CSF suggesting that Dexter cultures contain a supernatant inhibitor/inactivator of GM-CSF. The greatest capability of the artificial capillary culture system was to increase about 500-fold over monolayers the GM-CSF collected from bone fragment derived stromal cells. Unfortunately, CFU(s) maintenance was poor, the system was more expensive than monolayer cultures and, in our hands, suffered many mechanical failures usually resulting in loss of sterility. Histological evaluation suggested there was inadequate matrix for optimal attachment and growth of lymphohematopoietic stromal cells. Even so this system has a much greater potential for development than gelfoam sponges. Overall, Dexter cultures appear to be the most useful system currently available for the study of hematopoiesis and hematopoietic regulatory interactions.