Human Cell Culture

Recent findings in human cell cultures in vitro and in rats in vivo indicate that tungsten may have a synergistic effect with cobalt or nickel leading to tumorigenicity (Miller et al., 2001; Kalinich et al., 2005). Studies by Gatti et al. (2004) have documented nanometer-scale particles containing toxic metals (i.e. tungsten, aluminum, antimony, copper, gold, iron, lead, mercury, nickel, silver, titanium, zinc) in the bloodstream of humans. Since particles are suspected to trigger blood coagulation, this finding addresses the emerging problem of the lack of risk evaluation of nanoparticles in general.

Studies on human peripheral lymphocytes showed that genotoxic effects (DNA single-strand breaks) were evident after exposure to a combination of tungsten and cobalt (Anard et al., 1997; De Boeck et al., 1998).

Histological Clearing Agent

The use of tungsten in some diagnostic equipment such as radio-opaque catheters has led to a call for increased testing of biomaterialsTungsten acid added as a pure substance to culture medium stimulated metabolic activity in human urothelial cells (Pariente et al., 1999). Other studies using tungsten in aqueous solution support the view that tungsten itself produces toxicity at high concentrations that may not be exceeded in human serum (Peuster et al., 2003).

However, exposure to a metal powder containing tungsten in combination with cobalt and nickel resulted in a synergistic increase in DNA strand breakage and chromosomal aberrations in human osteoblast cells (Miller et al., 2001). Transformed cells showed alterations in ras oncogene expression and induced tumors when transplanted to nude mice, which was interpreted as representing neoplastic transformation of the osteoblast cells to a tumorigenic phenotype. Later studies indicate that synergistic effects may be related to epigenetic modifications triggered by tungsten alloy exposure that affect changes in intracellular calcium homeostasis (Verma et al., 2011).

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