Nickel hydroxy carbonate increases tumour necrosis factor alpha and interleukin 6 secretion by alveolar macrophages

Cytocompatibility and early inflammatory response of human endothelial cells in direct culture with Mg-Zn-Sr alloys

Crystalline Mg-Zinc (Zn)-Strontium (Sr) ternary alloys consist of elements naturally present in the human body and provide attractive mechanical and biodegradable properties for a variety of biomedical applications. The first objective of this study was to investigate the degradation and cytocompatibility of four Mg-4Zn-xSr alloys (x=0.15, 0.5, 1.0, 1.5wt%; designated as ZSr41A, B, C, and D respectively) in the direct culture with human umbilical vein endothelial cells (HUVEC) in vitro. The second objective was to investigate, for the first time, the early-stage inflammatory response in cultured HUVECs as indicated by the induction of vascular cellular adhesion molecule-1 (VCAM-1). The results showed that the 24-h in vitro degradation of the ZSr41 alloys containing a β-phase with a Zn/Sr at% ratio ∼1.5 was significantly faster than the ZSr41 alloys with Zn/Sr at% ∼1. Additionally, the adhesion density of HUVECs in the direct culture but not in direct contact with the ZSr41 alloys for up to 24h was not adversely affected by the degradation of the alloys. Importantly, neither culture media supplemented with up to 27.6mM Mg2+ ions nor media intentionally adjusted up to alkaline pH 9 induced any detectable adverse effects on HUVEC responses. In contrast, the significantly higher, yet non-cytotoxic, Zn2+ ion concentration from the degradation of ZSr41D alloy was likely the cause for the initially higher VCAM-1 expression on cultured HUVECs. Lastly, analysis of the HUVEC-ZSr41 interface showed near-complete absence of cell adhesion directly on the sample surface, most likely caused by either a high local alkalinity, change in surface topography, and/or surface composition. The direct culture method used in this study was proposed as a valuable tool for studying the design aspects of Zn-containing Mg-based biomaterials in vitro, in order to engineer solutions to address current shortcomings of Mg alloys for vascular device applications.

STATEMENT OF SIGNIFICANCE

Magnesium (Mg) alloys specifically designed for biodegradable implant applications have been the focus of biomedical research since the early 2000s. Physicochemical properties of Mg alloys make these metallic biomaterials excellent candidates for temporary biodegradable implants in orthopedic and cardiovascular applications. As Mg alloys continue to be investigated for biomedical applications, it is necessary to understand whether Mg-based materials or the alloying elements have the intrinsic ability to direct an immune response to improve implant integration while avoiding cell-biomaterial interactions leading to chronic inflammation and/or foreign body reactions. The present study utilized the direct culture method to investigate for the first time the in vitro transient inflammatory activation of endothelial cells induced by the degradation products of Zn-containing Mg alloys.

Interstitial pneumonia caused by inhalation of fumes of nickel and chrome

Two male industrial painters were admitted to hospital with dry cough and dyspnoea on exertion following a tank coating operation using a high-temperature spray paint consisting of a nickel-chromium alloy. Both patients showed hypoxaemia, peripheral leukocytosis, high levels of serum cytokines and bilateral ground-glass opacities on a chest CT scan. They were diagnosed with interstitial pneumonia caused by inhalation of nickel and chrome fumes and successfully treated with corticosteroid. These are rare cases of interstitial pneumonia associated with nickel/chromium inhalation.

Glucocorticoids augment the chemically induced production and gene expression of interleukin-1alpha through NF-kappaB and AP-1 activation in murine epidermal cells

To clarify the mechanism of the glucocorticoid-induced augmentation of skin response, we attempted to demonstrate the modulatory effect of glucocorticoids on the regulation of cytokines produced by keratinocytes stimulated with various chemicals in vitro. Haptens, irritants, and a superantigen (staphylococcal enterotoxin B) induced a significant release of interleukin-1alpha and tumor necrosis factor alpha, but not interleukin-10, from a murine keratinocyte cell line, Pam 212 cells. Glucocorticoids (10(-6)-10(-12) M) significantly augmented the production of interleukin-1alpha by Pam 212 cells at both the protein and mRNA levels when stimulated by either haptens or irritants, but not by staphylococcal enterotoxin B, whereas glucocorticoids alone had no effect. In contrast, glucocorticoids had no effect on the production of tumor necrosis factor alpha and interleukin-10 by chemically stimulated Pam 212 cells. Electrophoretic mobility shift assays revealed that chemical stimulation induced NF-kappaB activation in Pam 212 cells; however, augmented NF-kappaB activation by 10(-6)-10(-8) M of glucocorticoids was observed in Pam 212 cells stimulated by both haptens and irritants, but not by staphylococcal enterotoxin B. Furthermore, pyrrolidine dithiocarbamate inhibited the hapten-induced interleukin-1alpha production and NF-kappaB expression by Pam 212 cells. Pyrrolidine dithiocarbamate did not completely abrogate the hapten-induced interleukin-1alpha production augmented by glucocorticoids, however. To determine the effect on transcription factors other than NF-kappaB, AP-1 activity was examined by electrophoretic mobility shift assays. Hapten was founded to induce AP-1 activation in Pam 212 cells. In addition, AP-1 activation was augmented in the hapten-stimulated Pam 212 cells in the presence of 10(-8)-10(-10) M of glucocorticoids. The augmented inflammatory reaction by glucocorticoids may therefore reflect the augmentation of interleukin-1alpha production by keratinocytes mediated through the NF-kappaB and AP-1 pathway.

Effects of nickel sulfate on pulmonary natural immunity in Wistar rats

This study was designed to investigate the in vivo effect of nickel sulfate on the pulmonary non-specific immune defences. Groups of four male Wistar rats were treated with a single intratracheal instillation of NiSO(4) at different doses: 1, 2, 4 and 8 micromol of NiSO(4) per rat. Control rats received a corresponding instillation of the saline vehicle. The effect of NiSO(4) on the cytotoxic activity of the pulmonary natural killer (NK) cells and alveolar macrophages (AM), as well as the pulmonary production of cytokines such as alpha-tumor necrosis factor (TNF-alpha) and gamma-interferon (IFN-gamma), were examined 1, 2 and 7 days later. Spontaneous NK-cytotoxicity towards mouse-derived tumor cell line, Yac-1 was suppressed 1 day after treatment at doses of 2 micromol/rat and above with only one result significant (P<0.05); 2 days after treatment the suppression was increased with all results significant at the same doses; 1 week after treatment NK activity restoration was observed except for the highest dose, 8 micromol/rat. AM-mediated cytotoxicity towards mouse-derived tumor cell line, 3T12, did not show any significant difference in treated and untreated animals. In contrast, whereas moderate levels of TNF-alpha were detected in the broncho-alveolar lavage (BAL) fluid supernatants of controls, the NiSO(4) treatment highly suppressed TNF-alpha production with a maximum observed after 2 days. TNF-alpha suppression was found to be transient, at least with the lowest NiSO(4) dose, with levels returning to normal after 7 days. A non-significant increase in IFN-gamma was observed in the BAL fluids of treated animals at each time of examination. Taken together, these results indicate that NK cell activity and TNF-alpha secretion are sensitive targets for instilled NiSO(4) in Wistar rats.