IMMUNOREACTIVE OSTEOCALCIN FORMS IN CONDITIONED MEDIA FROM HUMAN OSTEOBLAST CULTURE AND IN SERA FROM HEALTHY ADULT CONTROL SUBJECTS AND PATIENTS WITH BONE PATHOLOGIES
Emd. Diego et al., IMMUNOREACTIVE OSTEOCALCIN FORMS IN CONDITIONED MEDIA FROM HUMAN OSTEOBLAST CULTURE AND IN SERA FROM HEALTHY ADULT CONTROL SUBJECTS AND PATIENTS WITH BONE PATHOLOGIES, European journal of clinical investigation, 28(1), 1998, pp. 48-58
Citations number
28
Categorie Soggetti
Medicine, Research & Experimental","Medicine, General & Internal
Background The aim of this work was to study the immunoreactive forms
of bone Gla protein (BGP) present in conditioned media of human osteob
last cultures (BGP released from osteoblast) and in the sera of health
y adult control subjects and patients with bone pathologies (chronic r
enal failure on haemodialysis, Pager's disease of bone and postmenopau
sal osteoporosis). Methods The technical procedure used was a combinat
ion of high-performance liquid chromatography (HPLC) and different BGP
assays with several specificities to analyse BGP levels in the differ
ent HPLC fractions. Aliquots of conditioned media or sera were purifie
d through a Sephadex G-50m column and by HPLC (C-4 reverse-phase colum
n) in a 25-40% acetonitrile gradient. Two-minute fractions were collec
ted and divided into three aliquots in order to determine osteocalcin
content using three different assays: (a) ELSA-OST-NAT IRMA, which onl
y detects intact osteocalcin; (b) ELSA-OSTEO IRMA, which detects intac
t osteocalcin and N-terminal fragments; and (c) OSCA Test RIA, which d
etects intact osteocalcin, C-terminal and other fragments. Results We
found different immunoreactive forms of osteocalcin in the culture med
ium of human osteoblasts and in sera from control subjects and patient
s for the bone pathologies studied. We did not find great qualitative
differences between the immunoreactive osteocalcin profile found in th
e culture medium from human osteoblasts and the sera from healthy cont
rol subjects. However, the different bone pathologies show different c
haracteristic patterns of immunoreactive forms of osteocalcin. Conclus
ions An interesting finding has been the detection, both in sera and i
n osteoblast culture media, of several immunoreactive forms of intact
osteocalcin that eluted from HPLC at different acetonitrile percentage
s, and therefore correspond to different molecular forms.