Evaluation of human polymorphonuclear behavior on textured titanium and calcium-phosphate coated surfaces

Few studies have evaluated the effects of titanium (Ti) surface modifications on polymorphonuclear neutrophils (PMNs). Human PMNs' viability and release of key mediators - such as IL1β, IL6, TNFα, IL12, IL10, IL4, TGFβ1, IL8, IP-10, and Mig - were evaluated on three different Ti surface treatments: (1) machined Ti; (2) alumina-blasted and acid-etched Ti (AB/AE); and (3) calcium phosphate coating of 300-500 nm by ion beam onto the AB/AE Ti surface (CaP). A polystyrene surface was used as a negative control. The PMNs were purified from whole human blood and cultured for 6 h. Cell viability was determined by flow cytometry, and the supernatant was evaluated to determine the levels of cytokines and chemokines. Results showed that the percentage of viable cells was significantly lower on the CaP surface compared to the control (p < 0.05) relative to the other groups. No differences in the levels of IL8, MIG, and IP10 were detected between groups. Significantly higher levels of IL1β (p = 0.046) and TNFα (p = 0.016) were detected for the CaP surfaces compared to AB/AE surface only. The levels of IL4, IL10, and TGFβ1 secreted from the PMNs in the CaP group were significantly lower than in the control and machined groups (p < 0.05) that were statistically comparable to AB/AE. Overall, the addition of a thin CaP coating to the AB/AE Ti surface influenced the secretion profile of pro-inflammatory cytokines due to the higher release of pro-inflammatory cytokines (IL1β and TNFα) on these surfaces.