A new study published in Spine examines implant materials for spinal surgery.
The researchers examined the difference between PEEK, which has fibrous connective tissue surface interface, and Ti-alloy implants with a complex micron/submicron scale roughness designed to promote osteoblastic differentiation. The researchers cultured human mesenchymal stem cells on tissue culture polystyrene, PEEK, smooth TiAIV or macro-/micro-/nano-textured rough TiAIV discs, according to the study abstract.
The researchers found:
1. The cells on PEEK upregulated mRNAs for:
• Chemokine ligand-2
• Interleukin 1ß
• IL6
• IL8
• Tumor necrosis
2. The cells on the mmnTiAIV showed an eight-fold mRNA reduction for toll-like receptor-4.
3. The mmnTiAIV cells also showed reduced proinflammatory interleukins levels.
4. The cells on PEEK reported higher mRNAs for the factors that were strongly associated with cell death/apoptosis.
5. The mmnTiAIV cells showed reduced cytokine factor levels.
"These results suggest that fibrous tissue around PEEK implants may be due to several factors: reduced osteoblastic differentiation of progenitor cells and production of an inflammatory environment that favors cell death via apoptosis and necrosis," concluded the study authors. "Ti alloy surfaces with complex macro/micro/nanoscale roughness promote osteoblastic differentiation and foster a certain specific cellular environment that favors bone formation."