Alterations in manganese, copper, and zinc contents, and intracellular status of the metal-containing superoxide dismutase in human mesothelioma cells

Associations between age and 50 trace element contents and relationships in intact thyroid of males

BACKGROUND

It is unclear why a prevalence of thyroid dysfunction is higher in the elderly as compared to the younger population. An excess or deficiency of trace element contents in thyroid may play important role in goitre- and carcinogenesis of gland.

AIM

To examine the variation with age of the mass fraction of 50 trace elements in intact (normal) male thyroid.

METHOD

Samples of thyroid parenchyma obtained from 72 healthy males (mean age 37.8 years, range 2-80 years) was investigated. Measurements were performed using a combination of non-destructive and destructive methods: instrumental neutron activation analysis and inductively coupled plasma mass spectrometry, respectively. Tissue samples were divided into two portions. One was used for morphological study while the other was intended for trace element analysis.

RESULTS

There is a statistically significant increase in Cd and Se mass fraction, as well as a decrease in Al, Be, Dy, Ga, Gd, Li, Mn, U, and Y mass fraction in the normal thyroid of male during a lifespan. Moreover, a disturbance of intra-thyroidal chemical element relationships (correlations) with increasing age was found.

DISCUSSION

Our findings suggest that, at least, a goitrogenic and carcinogenic effect of Cd overload and Mn deficiency in the thyroid of old males may be assumed. Many trace elements in human thyroid behave themselves as antagonists or synergists. Therefore, an age-related disturbance in correlations between Mn and other trace element mass fractions in thyroid parenchyma may also contribute to harmful effects on the gland.

CONCLUSION

Age-related changes in intra-thyroidal trace element contents and disturbances in trace element relationships are involved in goitre- and carcinogenesis.

Trace elements in hazardous mineral fibres

Both occupational and environmental exposure to asbestos-mineral fibres can be associated with lung diseases. The pathogenic effects are related to the dimension, biopersistence and chemical composition of the fibres. In addition to the major mineral elements, mineral fibres contain trace elements and their content may play a role in fibre toxicity. To shed light on the role of trace elements in asbestos carcinogenesis, knowledge on their concentration in asbestos-mineral fibres is mandatory. It is possible that trace elements play a synergetic factor in the pathogenesis of diseases caused by the inhalation of mineral fibres. In this paper, the concentration levels of trace elements from three chrysotile samples, four amphibole asbestos samples (UICC amosite, UICC anthophyllite, UICC crocidolite and tremolite) and fibrous erionite from Jersey, Nevada (USA) were determined using inductively coupled plasma mass spectrometry (ICP-MS). For all samples, the following trace elements were measured: Li, Be, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Sb, Cs, Ba, La, Pb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, U. Their distribution in the various mineral species is thoroughly discussed. The obtained results indicate that the amount of trace metals such as Mn, Cr, Co, Ni, Cu and Zn is higher in anthophyllite and chrysotile samples, whereas the amount of rare earth elements (REE) is higher in erionite and tremolite samples. The results of this work can be useful to the pathologists and biochemists who use asbestos minerals and fibrous erionite in-vitro studies as positive cyto- and geno-toxic standard references.

MWCNTs Induce ROS Generation, ERK Phosphorylation, and SOD-2 Expression in Human Mesothelial Cells

Biological oxidative responses are involved in the toxicity of multiwall carbon nanotubes (MWCNTs), which may cause asbestos-like pathogenicity. Superoxide dismutase 2 (SOD-2) has been proposed as a biomarker of early responses to mesothelioma-inducing fibers. This study was conducted to investigate the alteration of SOD-2 expression in the human mesothelial cell lines Met-5A after exposure to nontoxic doses of MWCNTs and the potential signaling pathway. The parameters measured included the viability, morphological change, superoxide formation, extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation, and messenger RNA (mRNA)/protein levels of SOD-2. Our results showed that MWCNTs upregulated SOD-2 expression at both mRNA and protein level. Coincidently, both superoxide formation and ERK1/2 phosphorylation were observed in Met-5A cells exposed to MWCNTs and were diminished by pretreatment with the reactive oxidative species (ROS) scavenger, N-acetyl-l-(+)-cysteine (NAC). To further investigate the role of ROS/ERK1/2 in MWCNTs-induced SOD-2 overexpression, prior to MWCNTs exposure, cells were pretreated with the Mitogen-activated protein kinase kinase 1/2 (MEK 1/2) inhibitor (U0126) or with NAC. Both pretreatments decreased the MWCNTs-induced overexpression of SOD-2. These results suggest that upregulation of SOD-2 in Met-5A cells exposed to MWCNTs is mediated by ROS formation and ERK1/2 activation.

Oxidative status and acute phase reactants in patients with environmental asbestos exposure and mesothelioma

Background and Objectives. The aim of this study was to investigate inflammatory indicators and oxidative status in patients with asbestos exposure with and without mesothelioma and to compare results with data from healthy subjects. Methods. Eighty people with exposure to environmental asbestos and without any disease, 46 mesothelioma patients, and a control group of 50 people without exposure to environmental asbestos were enrolled in this prospective study. Serum total oxidant level (TOL), total antioxidant capacity (TAC), and oxidative stress index (OSI), CRP, transferrin, ceruloplasmin, α-1 antitrypsin, ferritin, and copper levels were measured. Results. Mesothelioma group exhibited higher TOL, OSI, α1-antitrypsin, ferritin and copper levels as compared to the other groups (P < 0.001, P = 0.007, P < 0.0001, P < 0.001, and P < 0.001, resp.). Transferrin was lower in the mesothelioma group than in the other two groups (P < 0.001). The asbestos group had higher TOL, TAC, α1-antitrypsin, and transferrin levels (P < 0.001, P < 0.001, P < 0.001, and P < 0.001, resp.), as well as lower OSI and ferritin levels as compared to the control group (P < 0.001 and P < 0.001). Conclusions. We believe that elevated acute phase reactants and oxidative stress markers (TOL and OSI) in the mesothelioma group can be used as predictive markers for the development of asbestos-related malignancy.

Correlation of trace elemental profiles in blood samples of Indian patients with leukoplakia and oral submucous fibrosis

In order to ascertain possible correlation between alterations in trace elemental profile and the progression or regression of two most common potentially malignant disorders affecting oral cavity, namely oral submucous fibrosis and leukoplakia, blood from 60 patients from each group of patients as well from 30 healthy individuals was analyzed for elemental profiling employing EDXRF technique. Out of the 16 detected elements (K, Si, Ca, V, Cr, Ni, Mn, Fe, Cu, Zn, Se, Br, Rb, Sr, Co, and Pb), Mn, Fe, Zn, Br, and Co showed remarkable alteration in their profile in both leukoplakia and oral submucous fibrosis patients with respect to the normal healthy individuals. While Zn, Br, and Fe reflected similar changes--showing gross depletion in both the diseased groups, Mn and Co depicted inverse pattern of alterations in their concentrations in the two types of precancerous disorders when compared to the control subjects.

Molecular imaging of mesothelioma by detection of manganese-superoxide dismutase activity using manganese-enhanced magnetic resonance imaging

Malignant mesothelioma (MM) is a fatal malignancy with a rapidly increasing incidence in industrialized countries because of the widespread use of asbestos in the past centuries. Early diagnosis of MM is critical for a better prognosis, but this is often difficult because of the lack of disease-specific diagnostic imaging. Here, we report that manganese-enhanced magnetic resonance imaging (MEMRI) represents a promising approach for a more selective mesothelioma imaging by monitoring a high-level expression of manganese-superoxide dismutase (Mn-SOD), which is observed in many MM. We found that most human MM cells overexpressed Mn-SOD protein compared with human mesothelial cells and that NCI-H226 human MM cells highly expressed Mn-SOD and augmented Mn accumulation when loaded with manganese chloride (MnCl(2)). The cells showed marked T(1)-signal enhancement on in vitro MRI after incubation with MnCl(2) because of the T(1) shortening effect of Mn(2+). H226 subcutaneous tumor was preferentially enhanced compared with a lung adenocarcinoma cell tumor and another human MM cell tumor in MnCl(2)-enhanced T(1)-weighted MR image (T(1)WI), correlating with their respective Mn-SOD expression levels. Moreover, in a more clinically relevant setting, H226 xenografted pleural tumor was markedly enhanced and readily detected by MEMRI using manganese dipyridoxyl diphosphate (MnDPDP), a clinically used contrast agent, as well as MnCl(2). Therefore, we propose that MEMRI can be a potentially powerful method for noninvasive detection of MM, with high spatial resolution and marked signal enhancement, by targeting Mn-SOD.