Concentration of Insulin-Like Growth Factor (IGF)-I in Iliac Crest Bone Matrix in Premenopausal Women with Idiopathic Osteoporosis

Abstract

Previous studies have shown a link between low serum insulin-like growth factor-I (IGF-I) and decreased bone mass of patients with osteoporosis. However, whether serum levels are representative for the growth factor concentration or activity available in human bone tissue is controversial. In the present study, IGF-I was assessed in serum and bone matrix extracts from the iliac crest in 19 eugonadal women with idiopathic osteoporosis and in 38 age-matched controls. In addition, the relationship between the skeletal levels of IGF-I and bone mineral density (BMD) or the susceptibility to osteoporotic fractures in women with osteoporosis was examined. Bone matrix extraction was performed based on a guanidine-HCL/ethylendiamine-tetraacetic acid (EDTA) method. No significant difference in both serum and bone matrix IGF-I levels between groups was observed. Serum IGF-I concentrations failed to be associated with bone matrix IGF-I levels in osteoporotic patients. However, in premenopausal women with idiopathic osteoporosis, skeletal IGF-I positively correlated with BMD at the lumbar spine (r = + 0.58, p = 0.01). In contrast, neither femoral neck BMD nor Ward's triangle BMD was associated with bone matrix IGF-I concentrations. A tendency towards lower levels of bone matrix IGF-I in subjects with vertebral fractures as compared to those without fractures was observed in age-adjusted analyses, however the difference failed to remain statistically significant after adjustment for bone mineral density. These data provide no clear evidence for low bone matrix IGF-I as a determinant factor of age-unrelated osteoporosis. However, low skeletal IGF-I concentrations may aggravate osteoporosis in these women.

Quantification of growth factors in allogenic bone grafts extracted with three different methods

“…The elution of the homogenized bony material in PBS plus proteinase inhibitor (Complete) is very easy and fast. The two other methods—collagenase digestion ( Blum et al 2004 ; Laitinen et al 1997 ) and guanidine HCl extraction ( Pepene et al 2004 ; Sampath and Reddi 1981 )—are time consuming and laborious. Significant differences were found in the amount of extracted total protein.…”

“… Guanidine HCl/EDTA method: Thirty milligram of sample were placed in 1.5 ml Eppendorf tubes with 1.9 ml 4 M Guanidine HCl, 50 mM EDTA in 50 ml Tris pH 7.4 plus 5 mM benzamidine-HCl, 1 mM phenylmethylsulfonyl, and 0.1 mM aminocaproic acid. The samples were dialyzed against aqua dest at 4°C for 24 h with four changes (modified after ( Pepene et al 2004 ; Sampath and Reddi 1981 )). …”

ETIOLOGIYa I PATOGENEZ SNIZhENIYa KOSTNOYMASSY U ZhENShchIN MOLODOGO VOZRASTA (Obzor literatury)

“…Однако Pepene c соавт. не выяви-ли отличий в содержании ИФР-1 в сыворотке и матриксе кости у молодых женщин с нормой и сниженной МПК [63]. Haden c соавт.…”

Cancellous Bone Properties and Matrix Content of TGF-β2 and IGF-I in Human Tibia: A Pilot Study

“…Studies with human bone tissue indicate that bone matrix concentrations of TGF-β1, TGF-β2, and IGF-I are related to aging, metabolic bone disease, and fracture risk but the relationships may be gender and skeletal site dependent [ 1 , 7 , 29 , 38 , 46 , 49 , 50 , 54 , 57 , 64 ]. A few studies have examined the relationships of local matrix TGF-β1, TGF-β2, and IGF-I with bone mass and mechanical properties in human bone, however, the results have been conflicting [ 1 , 46 , 56 , 57 ].…”

“…For example, despite strong demonstrations in animal experiments, an association between bone volume fraction and the matrix concentrations of TGF- β1 or TGF-β2 was not found in the human iliac crest, femoral shaft, or lumbar spine [ 6 , 50 ]. The matrix concentration of IGF-I is correlated with bone density in the iliac crest and lumbar spine [ 49 , 57 ], but not in the proximal femoral shaft, femoral neck, or Ward’s triangle [ 49 , 56 ]. Apparent density and stiffness differences between the superior and inferior regions of the human femoral head are also not accompanied by differences in the matrix concentrations of IGF-I or IGF-II [ 58 ].…”