Epidermal growth factor, basic fibroblast growth factor and platelet-derived growth factor-bb can substitute for fetal bovine serum and compete with human platelet-rich plasma in the ex vivo expansion

Background aims

Human mesenchymal stromal cells (MSC) are multipotent cells possessing self-renewal
capacity, long-term viability and multilineage potential. We analyzed the effect of
four different medium supplements on the expansion and differentiation of adipose
tissue-derived MSC (ADSC) in order to avoid the use of xenogeneic serum.

Methods

We compared fetal bovine serum (FBS) with 10% human platelet-rich plasma (hPRP), 3%
human platelet-poor plasma (hPPP) and with a cytokine cocktail composed of epidermal
growth factor (EGF), basic fibroblast growth factor (bFGF) and platelet-derived growth
factor-bb (PDGFbb) added to 3% hPPP. This mixture was developed testing EGF, bFGF,
granulocyte–colony-stimulating factor (G-CSF), hepatocyte growth factor (HGF), insulin-like
growth factor (IGF-I), PDGFbb and transforming growth factor (TGF)-β1 added alone
or in combination with hPPP.

Results

Our data demonstrate that the addition of EGF, bFGF and PDGFbb, in a medium supplemented
with hPPP, obtainable from 150–200 mL whole autologous blood, supports ADSC expansion better than FBS, as confirmed by
cumulative population doublings (cPD; 15.0 ± 0.5 versus 9.4 ± 2.8). The addition of human platelet-rich plasma (hPRP) further improved ADSC proliferation
(cPD 20.0 ± 1.2), but the achievement of hPRP presented a major drawback, requiring 1000–1200 mL autologous or donor whole blood. The medium supplements did not influence ADSC
phenotype: they expressed CD105, CD90 and CD44 lacking hematopoietic antigens. The
exposure to the proposed cocktail or to hPRP increased adipogenic and osteogenic differentiation.

Conclusions

The addition of EGF, bFGF and PDGFbb to hPPP could ensure a sufficient number of ADSC
for clinical applications, avoiding the use of animal serum and representing a novel
approach in regenerative medicine.