Long-term Interactions of Circulating Neutrophils with Titanium Implants, the Role of Platelets in Regulation of Leukocyte Function

Despite the fact that different biomaterials are widely used in many biomedical applications, they can still cause side effects. Therefore, our aim was to assess neutrophil activity during the inflammatory phase of the repair process and long-term interactions between circulating neutrophils and Titanium (Ti) implants. Additionally, neutrophil in vitro response after stimulation by the extract of antimicrobial peptides (AMP extract), pentoxifylline (PTX) and some platelet-rich (L-PRP and PURE PRP) and platelet-poor (PPP) concentrates were tested. The study was conducted on eight sheep after Ti implant insertion into the tibia and revealed that the Ti implant did not cause any side effects during the course of experiment. After addition of L-PRP into neutrophils, culture activity of these cells significantly increased (p < 0.01), whereas treatment with AMP extract, PURE PRP, PPP or PTX caused decrease in neutrophil enzymatic response (on the basis of elastase, myeloperoxidase and alkaline phosphatase release) and free radical generation. These effects were observed in neutrophils isolated during the inflammatory phase as well as 4 and 10 months after implantation. Obtained results will be useful in regulation of inflammatory response during implantation of biomaterial and create possibility to modulate the cells response towards pro- or anti-inflammatory to reduce host tissue damage.