Interfaces between AISI 304 stainless steel screws and cranial bone were investigated after long-term implantation lasting for 42 years. Samples containing the interface regions were analyzed using state-of-the-art analytical techniques including secondary ion mass, Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopies. Local samples for scanning transmission electron microscopy were cut from the interface regions using the focused ion beam technique. A chemical composition across the interface was recorded in length scales covering micrometric and nanometric resolutions and relevant differences were found between peri-implant and the distant cranial bone, indicating generally younger bone tissue in the peri-implant area. Furthermore, the energy dispersive spectroscopy revealed an 80 nm thick steel surface layer enriched by oxygen suggesting that the AISI 304 material undergoes a corrosion attack. The attack is associated with transport of metallic ions, namely, ferrous and ferric iron, into the bone layer adjacent to the implant. The results comply with an anticipated interplay between released iron ions and osteoclast proliferation. The interplay gives rise to an autocatalytic process in which the iron ions stimulate the osteoclast activity while a formation of fresh bone resorption sites boosts the corrosion process through interactions between acidic osteoclast extracellular compartments and the implant surface. The autocatalytic process thus may account for an accelerated turnover of the peri-implant bone.
- MeSH
- fotoelektronová spektroskopie MeSH
- koroze MeSH
- kostní šrouby * škodlivé účinky MeSH
- lebka * patologie MeSH
- lidé MeSH
- nerezavějící ocel * chemie MeSH
- povrchové vlastnosti MeSH
- Ramanova spektroskopie MeSH
- rozhraní kost/implantát MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- železo chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE OF THE STUDY Nitinol (NiTi) is a biomaterial widely used in medicine based on super-elastic and shape memory properties. miR-124 has a key role in inflammatory process, osteoblasts differentiation, and mineralization. The aim of study was evaluating the differences in gene expression of miR-124 of human physiological osteoblasts (HOB) and human osteoarthritic osteoblasts (OSBA) as a response to NiTi alloy in different heat treatments. MATERIAL AND METHODS The cells were cultivated with NiTi discs with/without addition of bacterial lipopolysaccharide (LPS) for 72 hours. MicroRNAs were isolated, underwent reverse transcription and were analyzed by RT-PCR. RESULTS As a response to LPS, HOB overexpressed miR-124, while in OSBA expression change did not occur. Overexpression was also observed in both cell lines as a response to hydrogen and helium treated NiTi discs. HOB expressed significantly higher amount of miR-124 than OSBA as a response to hydrogen treatment of NiTi discs. In addition, hydrogen treatment caused significantly higher expression in HOB than LPS. The combination of NiTi disc and LPS treatment in HOB didn't cause any expression changes. Comparing to LPS-only treatment, the expression in HOB with combination of LPS and alloy was significantly lower. In OSBA, the expression was increased by the combination of LPS and hydrogen disc, in case of helium disc, the expression was decreased. CONCLUSIONS In conclusion, human physiological and osteoarthritic osteoblasts respond to NiTi alloy with both surface (hydrogen and helium atmosphere) treatment by overexpression of miR-124. The effect of LPS as inflammatory modulator suggests the presence of an "anti-inflammatory preconditioning" in osteoarthritic osteoblasts, as physiological osteoblasts overexpression was significantly higher. Key words: nitinol, osteoblast, miR-124, lipopolysaccharide.
- MeSH
- helium metabolismus farmakologie MeSH
- lidé MeSH
- lipopolysacharidy * farmakologie metabolismus MeSH
- mikro RNA * genetika metabolismus farmakologie MeSH
- osteoartróza genetika MeSH
- osteoblasty metabolismus MeSH
- slitiny metabolismus farmakologie MeSH
- titan MeSH
- vodík metabolismus farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Nickel-titanium alloys have been used in medical applications for several years; however, biocompatibility of the material remains controversial. In the present study, the human umbilical vein endothelial cells (HUVEC) were cultured in contact with the nitinol used in two different heat treatment surface modifications-helium and hydrogen. The amount of Ni ions released from these alloys in contact with HUVEC was measured in media and in the cells by ICP-MS. An increased release of Ni ions was detected in He alloy compared with H2 alloy modification with an elevation with the metal exposition duration (24 h vs. 72 h). The cells contained the Ni ions in both selected alloy modifications with the lower levels in H2 alloys. To evaluate the potential of multiple metal applications, similar values were observed in media and in cell suspension for all surface modification combinations. The model analysis of effect of metal ion release on distant cells in the body showed that the concentration is interestingly similar to concentrations in cells in direct contact with the metal alloy. The cells are able to regulate the concentration of Ni ions within the cell. According to our best knowledge, the study for the first time describes the presence of Ni ions released from nitinol directly in the cells. In the case of the H2 modification, the lowest levels of Ni ions were detected both in medium and in the cells, which likely increases the biocompatibility of the nitinol alloy.
Nickel-titanium alloy (nitinol, NiTi) is a biomaterial with unique thermal shape memory, superelasticity and high damping properties. Therefore NiTi has been used in medical applications. In this in vitro study, the effect of NiTi alloy (with two surface modifications - helium and hydrogen) on gene expression profile of selected interleukins (IL-1β, IL-6 and IL-8) and matrix metalloproteinases (MMP-1 and MMP-2) in human physiological osteoblasts and human osteoarthritic osteoblasts was examined to respond to a question of the different behavior of bone tissue in the implantation of metallic materials in the presence of cells affected by the osteoarthritic process. The cells were cultivated in contact with NiTi and with or without LPS (bacterial lipolysaccharide). Changes in expression of target genes were calculated by 2-ΔΔCt method. An increased gene expression of IL-1β in osteoarthritic osteoblasts, with even higher expression in cells collected directly from the metal surface was observed. In case of physiological osteoblasts, the change in expression was detected after LPS treatment in cells surrounding the disc. Higher expression levels of IL-8 were observed in osteoarthritic osteoblasts after NiTi treatment in contact with alloy, and in physiological osteoblasts without relation to location in combination of NiTi and LPS. IL-6 was slightly increased in physiological osteoblastes after application of LPS. MMP-1 expression level was obviously significantly higher in osteoarthritic osteoblasts with differences regarding the metal surface and location. MMP-2 expression was decreased in both cell lines after LPS treatment. In conclusion, results of present study show that the NiTi alloy and the treatment by LPS, especially repeated doses of LPS, change the gene expression of selected ILs and MMPs in human osteoblast cell cultures. Some of the changes were depicted solely to osteoarthritic osteoblasts.
- MeSH
- biokompatibilní materiály chemie farmakologie MeSH
- cytokiny MeSH
- kultivované buňky MeSH
- lidé MeSH
- lipopolysacharidy MeSH
- nikl farmakologie MeSH
- osteoartróza * MeSH
- osteoblasty účinky léků metabolismus MeSH
- regulace genové exprese účinky léků MeSH
- testování materiálů MeSH
- titan farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
