Abnormalities in the replicative capacity of osteoblastic cells in the proximal femur of patients with osteonecrosis of the femoral head.
OBJECTIVE
Aseptic nontraumatic osteonecrosis (ON) of the femoral head is a painful disorder that often leads to femoral head collapse due to subchondral fracture. We postulated that alteration of osteoblast function might play a role in the pathophysiology of ON. We evaluated the ex vivo proliferation rate and differentiation capacity of osteoblasts derived from the intertrochanteric region of the femur and of the iliac crest of patients with ON of the femoral head and compared it with patients with hip osteoarthritis (OA).


METHODS
We examined the function of osteoblastic cells in cultures derived from bone biopsies of the intertrochanteric region of the femur and of the iliac crest obtained from 13 patients with ON of the femoral head and 8 patients with hip OA. The replicative capacity was assessed by the proliferation rate in secondary culture. The phenotypic characterization was evaluated by the level of alkaline phosphatase activity, the sensitivity to 1,25 (OH)2 vitamin D3, and collagen synthesis.


RESULTS
The replicative capacity of the osteoblastic cells of the intertrochanteric area of the femur in ON patients was significantly reduced compared to patients with OA. The capacity of differentiation, however, was not different between ON and OA patients.


CONCLUSIONS
The replicative capacity of osteoblastic cells is significantly reduced in the femur of patients with ON. Our results confirm that altered osteoblastic function plays a role in the pathophysiology of ON of the femoral head.
Gangji
Valérie
V
Department of Rheumatology, Erasme University Hospital, Brussels, Belgium. vgangvi@ulb.ac.be
Hauzeur
Jean-Philippe
JP
Schoutens
André
A
Hinsenkamp
Maurice
M
Appelboom
Thierry
T
Egrise
Dominique
D
D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000378:metabolism; D002117:Calcitriol / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002455:Cell Division; D002478:Cells, Cultured; D005260:Female; D005270:Femur Head / Q000473:pathology*; D005271:Femur Head Necrosis / Q000473:pathology*; D006801:Humans; D007085:Ilium / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000473:pathology*; D010006:Osteoblasts / Q000187:drug effects / Q000201:enzymology / Q000473:pathology*; D010641:Phenotype
D002120:Calcium Channel Agonists; D000469:Alkaline Phosphatase; D002117:Calcitriol