Effects of granulation-tissue-conditioned medium on the growth of human keratinocytes in-vitro

Human keratinocyte cultures were seeded and grown for 24 hours in the presence of medium conditioned by exposure to granulation tissue and to normal tissue. The effects on cell proliferation were investigated by measurement of [3H]thymidine incorporation into cellular DNA. Keratinocyte growth was found to be markedly inhibited in the presence of granulation-tissue-conditioned medium (p much less than 0.05). Possible factors responsible for the inhibition have been investigated and the observations suggest that fibrin, or products derived from fibrin/fibrinogen may play a role in the suppression of cell growth.