title: Osteoblastic proliferation in bone biopsies from patients with end-stage chronic renal failure.
abstract: Osteoblasts have traditionally been considered to be terminally differentiated cells and therefore unable to divide. Data in recent years, however, indicate that cellular differentiation does not usually preclude preservation of proliferative ability and that most differentiated cells are able to divide under adequate stimuli. The aim of this study was to assess whether cubic osteoblasts undergo proliferation during the formation phase of the remodeling cycle under a stimulus that increased bone turnover. For that purpose, the osteoblastic proliferation index (OPI) was analyzed by DNA image cytometry in transiliac bone biopsies from 33 patients with chronic renal failure (23 men, 10 women; mean age 50.4 +/- 15.1 years) who have been classified into low (n = 13), normal (n = 15), and high (n = 15) bone turnover according to activation frequency (Ac.f). OPI was significantly higher (p < 0.002) in the high bone turnover group (13.90 +/- 4.72%) compared with the low (2.38 +/- 4.13%) and normal turnover groups (2.84 +/- 4.04%). There was a positive correlation between OPI and the following histomorphometric parameters: bone formation rate, surface referent (r = 0.76, p = 0.00001), activation frequency (r = 0.73, p = 0.00001), mineral apposition rate (r = 0.73, p = 0.00001), bone formation rate, volume referent (r = 0.71, p = 0.00001), and mineralizing surface (r = 0.62, p = 0.0001). This study shows that a rise in bone turnover is associated with a marked increase of bone-forming cell proliferation in patients with end-stage chronic renal failure. From this finding, it may be concluded that cubic osteoblasts do not behave as "terminally differentiated" cells in vivo, because a high proportion of them are still able to divide.
authors.affiliation: Metabolic Unit, Hospital del Mar-IMIM, Autonomous University of Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Serrano
authors.forename: M L
authors.initials: ML
authors.lastname: Mariñoso
authors.forename: A
authors.initials: A
authors.lastname: Torres
authors.forename: V
authors.initials: V
authors.lastname: Lorenzo
authors.forename: U
authors.initials: U
authors.lastname: Keysers
authors.forename: J
authors.initials: J
authors.lastname: Lloreta
authors.forename: M
authors.initials: M
authors.lastname: Nacher
authors.forename: C
authors.initials: C
authors.lastname: Garcia
authors.forename: J
authors.initials: J
authors.lastname: Ballester
authors.forename: A
authors.initials: A
authors.lastname: Diez
authors.forename: J
authors.initials: J
authors.lastname: Aubia
mesh_terms: D000328:Adult; D000368:Aged; D001842:Bone and Bones / Q000378:metabolism; D002455:Cell Division; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D019044:Image Cytometry; D007676:Kidney Failure, Chronic / Q000097:blood / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000473:pathology*; D011446:Prospective Studies