IADR Abstract Archives

Impact of IGF-2 on PDL Cell Homeostasis in Different Conditions

Objectives: Insulin-like Growth Factor (IGF) 2 has a high sequence similarity to insulin and represents a member of the IGF system, which also includes IGF-1, cell-surface receptors, IGF-binding proteins (IGFBPs) and their degrading enzymes. Although the role of IGF-1 has been clarified in our previous studies, little is as yet known about the effects of IGF-2 on the periodontal ligament (PDL). This in-vitro study was established to examine the impact of IGF-2 on PDL cell proliferation, differentiation, and apoptosis as well as the IGF system in several clinically relevant conditions, such as oxygen deficiency and biomechanical loading.

Methods: PDL cells derived from human teeth were stimulated with IGF-2 in the presence and absence of oxygen deficiency (3% O2) or dynamic tensile strain applied to mimic biomechanical loading conditions for different time periods. Proliferation was analyzed by WST-1, nuclear incorporation of bromodeoxyuridine, cell counting, and real-time PCR. Apoptosis was determined by a cell death detection ELISA. Cell differentiation was assessed by studying the gene expression of osteogenesis-related molecules (alkaline phosphatase, runx2, osteopontin, periostin and S100A4 by real-time PCR. For blocking the phosphoinositide 3-kinase pathway, wortmannin was used. For statistical analysis, the Mann-Whitney test (p<0.05) was applied.

Results: Under normal conditions, IGF-2 increased significantly cell proliferation and this stimulatory effect could be neutralized by wortmannin. In the presence of oxygen deficiency, the IGF-2-induced effect on cell proliferation was significantly enhanced. IGF-2 did not change the apoptosis rate in any condition. Additionally, IGF-2 stimulated its own synthesis but did not affect IGF-1 expression. Finally, IGF-2 regulated the expression of IGFBPs and these effects were modified by oxygen deficiency and biomechanical loading.

Conclusions: Our findings show that IGF-2 can regulate, at least in part, PDL homeostasis. However, the IGF-2 effects seem to be strongly dependent on the cellular environment.

Acknowledgment: Clinical Research Unit (KFO208/TP7)

Pan European Region Meeting
2012 Pan European Region Meeting (Helisinki, Finland)
Helisinki, Finland
2012
79
Scientific Groups
  • Rath-deschner, Birgit  ( University of Bonn, Bonn, N/A, Germany )
  • Memmert, Svenja  ( University of Bonn, Bonn, N/A, Germany )
  • Deschner, James  ( University of Bonn, Bonn, N/A, Germany )
  • Jäger, Andreas  ( University of Bonn, Bonn, N/A, Germany )
  • Götz, Werner  ( University of Bonn, Bonn, N/A, Germany )
    • Oral Session
    Periodontal Research
    09/13/2012