Role of endogenous polyamines in the proliferation of normal hematopoietic progenitor cells: high-proliferative potential colony-forming cells (HPP-CFC), and low-proliferative potential colony-forming cells (LPP-CFC). Studies "in vitro"

This study concerns the role of endogenous polyamines in the proliferation of normal hematopoietic progenitor cells: high-proliferative potential colony-forming cells (HPP-CFC), and low-proliferative potential colony-forming cells (LPP-CFC) in CFW/ep mouse bone marrow cells in the agar culture system. DL-a-difluoromethylornithine (DFMO) was used as a selective and irreversible inhibitor of ornithine decarboxylase which is the first limiting step in polyamine biosynthesis. The polyamines have been implicated in cell proliferation and differentiation. The results showed that DFMO significantly inhibited the formation of LPP-CFC colonies and completely inhibited the growth of the HPP-CFC colonies. Addition of exogenous putrescine at the concentration of 10(-7) M reverses the suppressive action of DFMO in both progenitor cells. At this concentration putrescine alone had no affect on the number or the size of the colonies. It was then concluded that endogenous polyamines appear to be essential for HPP-CFC proliferation and an important requirement for LPP-CFC proliferation.

Synergistic activity for high proliferative potential colony forming cell (HPP CFC) development, stable to trypsin digestion, present in pregnant mouse uterus and placenta extract

Se estudió la ación "in vitro" del extracto de embriones y úteros de ratón preñado (PMUE), que promueve el desarrollo de grandes colonias de células progenitoras comprometidas de alto potencial prolifarativo (HPP-CFC) y su diferenciación a macrófagos. El extracto se obtuvo de la cepa CFW/ep y tanto las células de la médula ósea de ésta como las de ratones suizos normales se cultivaron en medio semisólido con agar para demostrar la acción biológica del PMUE y medio condicionante de placenta humana (HPCM). La proliferación de esas células progenitoreas muy primitivas requiere la presencia concurrente de un factor estimulante de macrófagos - CSF - y de un factor sinergístico (SF). La actividad biológica de ambos está presente en el extracto, encontrándose la mayor actividad en útero y placenta. El SF precipita con sulfato de amonio con más de 45% de saturación, no es dializable y es termiestable (a 70-C durante 15 min). Se destaca su resistencia a la acción enzimática de la tripsina