Bone disease in long-term renal transplant recipients with severe osteopenia: a cross-sectional study.
BACKGROUND
Fracture is a disabling clinical outcome after transplantation, but there is little histopathological information on long-term renal recipients with severe osteopenia.


METHODS
Twenty kidney recipients (8.3+/-1.9 years after transplantation), 13 males and 7 females (five postmenopausal) with nearly normal renal function, affected by severe osteopenia (T-score: males= -4.9+/-0.28; females= -5.08+/-0.47) underwent bone biopsy and morphometric X-ray absorptiometry to evaluate vertebral fractures.


RESULTS
Histopathological diagnosis was osteoporosis-osteopenia in seven patients, osteitis fibrosa in six, prevalent osteomalacic lesion in six, and "normal" bone in one patient. Significant increases in osteoid volume (OV/BV), osteoid surface, osteoblastic surface (ObS/BS) and osteoid thickness were observed. OV/BV and Obs/BS ratios were inversely correlated to cumulative doses of MPRED (r2=0.85 P<.0001 for both ratios), whereas age, sex, time after transplantation, iPTH levels, and cumulative cyclosporine A dose were not related to osteoblastic indices. Osteoclast surface was slightly increased. Widened mineralization lag times were observed, with normalcy of the bone formation rate. Half of the patients showed fractured vertebrae. No differences in T scores were found when patients were subdivided into groups "with" or "without" vertebral fractures. A higher prevalence of fractures was observed in patients with osteoporosis-osteopenia compared to other osteopathies (P<0.02). No relationships between bone volume versus T-scores were observed.


CONCLUSIONS
In long-term renal transplant recipients, severe osteopenia does not predict osteoporosis alone. The main abnormality we found was an increase in osteoblastic activity with a slight mineralization defect. The heterogeneous bone illness we observed would suggest performing bone biopsy in these patients.
Rolla
Davide
D
Division of Nephrology, Dialysis, and Transplantation, Azienda Ospedale S. Martino, Largo R. Benzi 10, 16132 Genoa, Italy. davide.rolla@hsanmartino.it
Ballanti
Paola
P
Marsano
Luigina
L
Bianchi
Gerolamo
G
Messa
Piergiorgio
P
Paoletti
Ernesto
E
Cannella
Giuseppe
G
D000328:Adult; D000368:Aged; D001706:Biopsy; D001847:Bone Diseases / Q000209:etiology*; D001851:Bone Diseases, Metabolic / Q000150:complications*; D001842:Bone and Bones / Q000473:pathology; D003430:Cross-Sectional Studies; D016572:Cyclosporine / Q000494:pharmacology; D005260:Female; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000502:physiology; D016103:Spinal Fractures / Q000209:etiology
D016572:Cyclosporine