Effect of Different Forms of Human Platelet Lysate on the Proliferation and Phenotype of Human Osteoblasts

Background and aims: Enhanced cell proliferation is crucial for reducing production time and cost in cell therapy, and human platelet lysate (HPL) is often used to boost cell proliferation due to its favorable safety profile. Understanding the roles of different HPL components and their effects on cell culture can lead to more informed choices in medium formulation, which in turn can influence cell behavior and outcomes. Therefore, this study aimed to investigate the effects of two types of HPL, i.e., heparin-supplemented HPL (He-HPL) and fibrinogen-depleted HPL without heparin (Fd-HPL), on human osteoblasts. Materials and Methods: He-HPL and Fd-HPL were prepared from expired platelet concentrates. The presence of growth factors, i.e., brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), and cytokines, i.e., interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha), in HPL was evaluated. Human fetal osteoblast (hFOB) cells were cultured in Dulbecco's Modified Eagle Medium supplemented with either He-HPL or Fd-HPL. The cell morphology, viability, calcium deposition, and expression of osteogenic genes were assessed. Results: Comparable levels of BDNF (p > 0.05), VEGF (p > 0.05), and IL-6 (p > 0.05) were detected in both types of HPL, whereas He-HPL exhibited significantly higher levels of TNF-alpha (p < 0.05). However, there were no notable differences in cell morphology, viability, population doubling time, or total cell yield between the two HPL types. Similarly, no differences were observed in the mineralization of cells treated with He-HPL compared to Fd-HPL. Nonetheless, hFOB cells cultured with He-HPL demonstrated significantly higher expression of osteogenic markers Runx2 and ALP (p < 0.05) compared to those cultured with Fd-HPL. Conclusions: He-HPL and Fd-HPL demonstrate comparable performance in promoting osteoblast proliferation and mineralization, making both usable for bone tissue engineering. However, He-HPL might have a slight edge as it enhances osteogenic gene expression.