Pyran copolymer: effect of molecular weight on stem cell mobilization in mice.

Maleic anhydride divinly ether copolymer polyanions (MVE) of well defined molecular weight ranging from 12,000 to 52,000 and Pyran Copolymer (NSC 46015), a MVE preparation with broader molecular weight range, were tested for their ability to mobilize murine stem cells, colony forming units spleen (CFU-S) and colony forming units in culture (CFU-C). Maximal mobilization of circulating stem cells was seen five days after Pyran Colopymer injection. This time point was chosen to determine the mobilization effect of different MVE preparations. It was found that the mobilization paralleled the molecular weight: the observed increase of circulation CFU-S by fractions MVE II, III, IV, and V and NSC 46015 were 3, 5, 14, and 20 fold.