Effects of autologous serum on osteoblastic differentiation in human bone marrow cells.

Background: Expanding cells ex vivo is an important step in tissue engineering and the culture medium is usually supplemented with bovine serum. When a patient receives bone marrow stromal cells (BMSCs) grown in a medium containing bovine serum, infection of bovine diseases and/or the patient's unfavorable immune reaction to bovine proteins are of concern. To overcome these problems, we examined whether a patient's autologous serum could support the growth and differentiation of his/her BMSCs.

Methods: Bone marrow was collected from the iliac by aspiration and cultured in a medium supplemented with 10% autologous serum or 10% fetal bovine serum (FBS). Number and area of the colonies of fibroblast-like cells (colony-forming unit fibroblast, CFU-f) were measured 8 days after the cell inoculation (day 8). Number and area of the alkaline phosphatase (ALP) positive colonies were measured on day 10. On day 40, the cultures were stained with alizarin red S. RNA was prepared from the culture on day 20, and the mRNA expression of osteoblastic genes was examined by reverse transcription polymerase chain reaction (RT-PCR) analysis.

Results: BMSCs, which were cultured in the medium supplemented with autologous serum, produced CFU-f, ALP-positive area and mineralized nodules, which is comparable to the BMSCs in the culture supplemented with FBS. The mRNA expressions of osteopontin, parathyroid hormone receptor, osteocalcin, and bone sialoprotein were detected in the culture supplemented with autologous serum.

Conclusions: A patient's autologous serum could expand BMSCs without losing their potentiality for osteoblastic differentiation. Patients' autologous serum could be efficient to expand BMSCs and to be utilized safely for bone regeneration therapy.