Transforming growth factor-beta 1 (TGF-β1) prevents the age-dependent decrease in bone formation in human osteoblast/implant cultures

Titanium implants have been extensively used in orthopedic surgery and dentistry. Most of the patients who receive such implants are elderly with a compromised ability to heal and form new bone. By using an in vitro osteoblast/implant culture system, the potency of TGF-beta 1 in enhancing mineralization of human osteoblast cultures from elderly subjects was investigated in this study. Primary human osteoblast (HOB) cells obtained from different age group human subjects [Young (Y), Middle (M), and Old (0)] were cultured on Ti alloy (Ti-6Al-4V) disks with or without continuous administration of 0.2 ng/mL TGF-beta 1 in the medium for 2 or 4 weeks. TGF-beta 1 significantly (p < 0.05) increased calcium content and the size of calcified nodules on implant disks in the 0 group, but had no effect on the Y or M groups. The number of calcified nodules was not different with or without TGF-beta 1 in all age groups. As measured by Northern blot analysis and RT-PCR, TGF-beta 1 significantly increased the expression of bone-specific extracellular matrix proteins, including alkaline phosphatase, Type I collagen, bone sialoprotein and osteocalcin, after both 2 and 4 weeks in the 0 group but not in the Y group. In conclusion, TGF-beta 1 enhances mineralization on implant materials of osteoblast cultures from elderly human subjects. (c) 2005 Wiley Periodicals, Inc.