MYCOPHENOLATE MOFETIL - A PROMISING NEW IMMUNOSUPPRESSANT THAT DOES NOT CAUSE BONE LOSS IN THE RAT

Background. Posttransplantation bone disease is a well-described pheno menon; among its etiology is immunosuppressant-induced bone disease. M ycophenolate mofetil (MMF) has emerged as a promising new immunosuppre ssant. Our study was designed to investigate the effect of MMF on in v ivo bone mineral metabolism. Methods. Twenty-four 6-month-old male Spr ague-Dawley rats were randomized into two groups to receive either MMF vehicle daily for 28 days or 30 mg/kg MMF daily for 28 days. The seru m was assayed for osteocalcin and 1,25-dihydroxy vitamin D-3. Subseque nt to double-labeling, the right tibiae were removed on day 28 for his tomorphometry. Results. MMF suppressed bone gla protein (osteocalcin) levels on days 14 and 28 (P<0.05). Except for percentage osteoid perim eter, there was no difference in bone histomorphometry between the two groups, Conclusion, In this relatively short-term study, MMF did not cause osteopenia in the rat model, but the suppressed bone gla protein merits further study.