Effects of soluble metals on human peri‐implant cells

Abstract

Despite reports associating tissue necrosis with implant failure, the degree to which processes, such as metal toxicity, negatively impact implant performance is unknown. We evaluated representative human peri-implant cells (i.e., osteoblasts, fibroblasts, and lymphocytes) when challenged by Al+3, Co+2, Cr+3, Fe+3, Mo+5, Ni+2, and V+3 chloride solutions (and Na+2 as a control) over a wide range of concentrations (0.01-10.0 mM). Cell responses were measured using proliferation assays, viability assays, and microscopic cell morphology assessments. Differential effects were found to be less a function of the cell type than of the composition and concentration of metal challenge. No preferential immunosuppression was demonstrated. Below 0.01 mM, no metal was toxic. The most toxic metals (i.e., Co, Ni, and V) reduced proliferation (IC50), and viability (LC50) and cell morphology of osteoblasts, fibroblasts, and lymphocytes by <50% at challenge concentrations <1 mM. All other metals tested required >5 mM to exact the same responses. Below 1 mM, these toxic metals also induced alterations in all cell morphology consisting of loss of filopodia or lamellipodia or changes in cell shape. Metals that were toxic at clinically relevant concentrations (less than previously reported values in peri-implant tissues/fluids) include Co (0.6 mM), Ni (0.8 mM), V (0.5 mM) for lymphocytes and Co (0.8 mM), V (0.3 mM), Al (1-5 mM), Fe (1-5 mM) for fibroblasts, and Co (0.8 mM), Ni (0.7 mM), V (0.1 mM) for osteoblasts. Only Co and V were toxic in vitro at concentrations below that detected in vivo in synovial fluid (V at 0.1 mM and Co at 0.8 mM for fibroblasts, and V at 0.4 mM and Co at 0.8 mM on osteoblasts). Thus, soluble Co and V released from Co- and Ti-based alloys, respectively, could be implicated as the most likely to mediate cell toxicity in the periprosthetic milieu.

Potential of FeAlCr intermetallics reinforced with nanoparticles as new biomaterials for medical devices

“…41 In a recent study using both primary and established cells Cr and Al are classified as "moderately to mildly toxic" for osteoblasts, as some effects on cells were assessed at a concentration around 5mM. 42 Our results confirm that osteoblast-like cells can easily bear ion release from ALUSI alloys.…”

Biocompatibility of Ti-8Ta-3Nb alloy with fetal rat calvarial cells

“…Okazaki et al 25) reported that metallic ions such as Ti, Zr, Sn, Nb, and Ta had evidently no harmful effects on the growth ratios of cells however, Al and V ions presented lower rate as compared to that of titanium ion. Hallab et al 26) . also showed that cobalt (Co) and V released from Co-and Ti-based alloys respectively, could mediate cell cytotoxicity in the joint periprosthetic milieu.…”

“…Among titanium alloys employed as metallic implant materials, Ti-6Al-4V has been widely used in dental and medical fields. Although this alloy is still widely used in dental and medical fields, some concerns such as toxicity of V and Al and high elastic modulus, have been reported [6][7][8] . Surface roughness and topography can greatly affect the proliferation and protein synthesis of osteoblast cells that are cultured on a metal substrate characteristics in the healing of bone 21,22) .…”

“…However because of needs to improve its mechanical properties, titanium alloys such as Ti-6Al-4V, Ti-6Al-7Nb, have also been used for dental and orthopedic material [3][4][5] . 1) Although titanium alloys are still widely used in medicine, some concern has been expressed over its use since it appears that small amounts of both vanadium and aluminum, released in the human body, induce possible cytotoxic effect and neurological disorders, respectively [6][7][8] .…”

Microstructure, mechanical property, corrosion behavior, and in vitro biocompatibility of Zr–Mo alloys

“…Early studies demonstrated that below 0.01 mM, neither Zr nor Mo was toxic to osteoblasts and fibroblasts. 5,55 In addition, the biocompatibility of Zr-Mo alloys was primarily evaluated by culturing L-929 cells and MG 63 cells in their extraction media and positive results were obtained, indicating an excellent in vitro biocompatibility.…”