Preferential degradation of osteoclasts by titanium tetrachloride

Abstract

Although titanium alloys are known to be biocompatible with bone tissue after implantation in human beings, the effect of titanium on osteoclasts remains to be studied. We examined the effect of titanium salt on the formation and survival of osteoclasts in cell culture. The addition of 10 microM titanium tetrachloride caused a decrease in the cell number of osteoclast-like cells induced in bone marrow cell cultures taken from mice. The addition of 10 microM titanium tetrachloride caused degradation of the disaggregated osteoclasts taken from neonatal rats and a decrease in bone resorption. Along with the increase in the degradation of osteoclasts, the number of apoptotic cells increased. Titanium tetrachloride dose-dependently decreased the cell number and alkaline phosphatase activity of osteoblastic cell cultures taken from rat calvaria. However, these concentrations were 30-40 times higher than those in the case of osteoclast-like cell formation. These results showed that titanium ions caused a preferential degradation of osteoclasts rather than osteoblasts, most likely by apoptosis.

Inhibitory effect of titanium particles on osteoclast formation generated by treatment of mouse bone marrow cells with PGE2

“…However, recent evidence shows that these inflammatory responses to Ti particles are based on the adherent endotoxin to Ti particles (Bi et al , 2001) and that Ti ions inhibit osteoclast formation induced by PGE 2 . In an in vitro study Matsunaga et al (2001) questioned whether Ti particles are directly involved in osteolysis caused by wear debris. In the present study, we found, rather unexpectedly, that Ti particles with no adherent endotoxin inhibited osteoclastogenesis without affecting osteoclastic bone resorbing activity.…”

Effects of thirty elements on bone metabolism

“…Some data indicates they promote osteoclast-induced bone resorption, possibly through cytokine modulation. Other data indicates titanium ions induce osteoclast apoptosis [13,88,290].…”

Behavior of SaOS-2 Cells Cultured on Different Titanium Surfaces

“…Apoptosis, or physiologic cell death, is based on an endogenous cell suicide mechanism, which can be selectively triggered by the cells in response to as-yet-largely-unknown stimuli (Cohen, 1993). Recently, it has been shown that titanium ions cause a preferential degradation of osteoclasts rather than osteoblasts, most likely by an apoptotic mechanism (Matsunaga et al, 2001). However, studies regarding the effects on apoptosis of surface topography of titanium dental implants are limited, and such effects, if any, are largely unknown.…”