The effect of extended storage on EGF and TGF-β1 biochemical factor stability in AM substrates.

EGF (A) and TGF-β1 (B) levels were measured by ELISA in AM substrates stored for extended periods of 4, 8, 12, 24, 48 and 60 weeks, away from direct light and at ambient temperature. No significant changes in EGF concentration were measured in any of the AM substrates following extended storage. The TGF-β1 profile illustrates biological variation between samples and a significant decrease (*p<0.05) in TGF-β1 levels in cryopreserved AM following 60 weeks of storage compared to 4 weeks. Data are expressed as mean ± SEM based on three separate experiments.