Osteogenic Activity Associated With Porous Tantalum Implants in Diabetic Patients

Objectives: The aim of this study was to identify differentially expressed genes and associated molecular pathways involved in early wound healing and osteogenesis (at two weeks) around porous tantalum implants as compared to titanium implants among diabetic patients.
Methods: Eight controlled type 2 diabetes mellitus (T2DM) patients with HbA1c levels of 7.0–8.9 were enrolled following an IRB approved protocol. For each patient, porous tantalum test cylinders or titanium cylinders were placed on the mandible using a split mouth approach. Test cylinders were removed at 2 weeks using a slightly larger trephine drill and sites received a screw vent implant (Zimmer Dental, Carlsbad, CA, USA). Biopsy samples collected from each test cylinder were processed for quantitative mRNA expression measurements relative to housekeeping genes using TaqMan® microarray panels focusing on wound healing and osteogenesis and major molecular and cellular pathways were identified using Ingenuity Pathway Analysis.
Results: Analysis revealed a 4-9 fold upregulation of genes BGLAP, BMP5, COL1A1, FGFR2, IGF1, MMP2, PHEX, RUNX2, TGFB1, TWIST1, VEGFB in diabetic patients with porous tantalum cylinders as compared to diabetic patients with titanium cylinders at 2 weeks post-cylinder placement. MMP10 and CSF3 appeared downregulated in the porous tantalum diabetes patient group at this early osteogenic phase.
Conclusions: These preliminary data suggest that the use of porous tantalum cylinders implanted in subjects with controlled T2DM showed upregulation of key genes involved in osteogenesis during initial phase of wound healing when compared to titanium cylinders. These findings suggest that further refinement of implant material and design may lead to improved osteogenesis among subjects with diabetes.