Different Effects of Insulin and Insulin-Like Growth Factors I and II on Osteoprogenitors and Adipocyte Progenitors in Fetal Rat Bone Cell Populations

Abstract

We investigated the effects of insulin (1-1,000 nM), insulin-like growth factor (IGF)-I, and IGF-II (3-100 nM each) alone or together with 10 nM dexamethasone (DEX) or 10 nM 1,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3)) on proliferation and differentiation of adipocyte and osteoblast progenitors in bone cell populations derived from fetal rat calvaria. The effects on differentiation were evaluated by counting the number of bone or osteoid nodules and adipocyte colonies and the effects on proliferation, by measuring their size by image analysis. The types of cells studied were 1,25(OH)(2)D(3)- and DEX-responsive adipocyte progenitors and DEX-dependent and independent osteoprogenitors. Both IGF-I and IGF-II stimulated osteoprogenitor differentiation both alone and in the presence of DEX, while insulin stimulated osteoprogenitor differentiation only in the absence of DEX. Neither IGF-I/-II nor insulin affected proliferation of osteoprogenitors. Insulin had little effect on adipocyte differentiation by itself but strongly stimulated differentiation in the presence of either 1,25(OH)(2)D(3) or DEX, while IGF-II stimulated adipocyte differentiation in both the absence and presence of 1,25(OH)(2)D(3) or DEX. IGF-I by itself or in the presence of DEX strongly stimulated adipocyte cell differentiation but had little effect in the presence of 1,25(OH)(2)D(3). Our results demonstrate that insulin, IGF-II, and IGF-I have specific and different effects on the differentiation and proliferation of different groups of progenitor cells.

Effects of local insulin delivery on subperiosteal angiogenesis and mineralized tissue formation during fracture healing

“…Local UL treatment did not significantly increase cellular proliferation within the fracture callus, contrary to previous studies examining the effects of insulin and IGF‐1 on fracture healing 17, 18. Others studies suggest that insulin treatment in a non‐diabetic population may not necessarily induce mitogenesis 19, 20. Fulzele et al found that insulin treatment did not affect osteoblast cell proliferation in culture media, compared to untreated osteoblasts 20…”

The Differentiation and Gene Expression Profile of Human Dental Follicle Cells

“…IGF2 is a growth factor that is highly expressed in bone tissue [ 17 ]. A stimulatory effect of IGF2 on cell proliferation, differentiation, and mineralization was demonstrated for rat osteogenic progenitor cells [ 18 ]. We had found in a qRT-PCR analysis that IGF2 was differentially expressed in human DFCs compared with…”

Differential in-gel electrophoresis (DIGE) analysis of human bone marrow osteoprogenitor cell contact guidance

“…These comprise a mixture of cells, from primitive mesenchymal stem cells to mature osteoblasts, with precursor cells in between at different stages of commitment [5,6]. This heterogenous cell mix has the potential to differentiate into bone-forming cells/osteoblasts under appropriate conditions using selected hormones/growth factors [7][8][9], vitamins/chemical reagents [10,11] and/or defined surface topographical guidance [12][13][14][15].…”