Blood translation elongation factor-1δ is a novel marker for cadmium exposure.

Translation elongation factor-1d (TEF-1δ) has been identified as a novel cadmium-responsive proto-oncogene. However, it is still unclear whether TEF-1δ could be a potential biomarker of cadmium exposure. Rats were treated with CdCl2 at different concentrations (high dose 1.225, mid-dose 0.612 and low dose 0.306 mg/kg body weight, respectively) for 14 weeks, and the cadmium levels, weight coefficients, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), serum creatinine (SCR), 24-h urine protein (24hPro), urinary creatinine (Cr) and pathological features were determined. The TEF-1δ expression in white blood cells and multiple organs were examined by reverse transcription polymerase chain reaction (PCR) and were also confirmed with fluorescence quantitative PCR. A cadmium dose-dependent increase (p < 0.05) of cadmium levels in blood, urine, liver, kidney, heart and lung, and the weight coefficients was observed. The liver and renal function indictors including AST, ALT, SCR, BUN and 24hPro, were elevated in a cadmium dose-dependent manner (p < 0.05). Significant pathological changes in liver, kidney, heart and lung were indicated. The TEF-1δ expression was up-regulated in both blood and organs (p < 0.05). Moreover, the expression level of blood TEF-1δ was positively correlated to TEF-1δ expression level, cadmium level and toxicity in the organs (p < 0.01). This study indicates that blood TEF-1δ is a novel valuable biomarker for cadmium exposure and its organ toxicity.

Alterations in the expression of translation factors as molecular markers in cadmium-exposed workers.

Eukaryotic translation initiation factor 3 (eIF3) and elongation factor 1δ (eEF-1δ) are novel cadmium (Cd) responsive proto-oncogenes. This research investigated the expression of these genes in Cd-exposed workers (n = 58), and to evaluate their usefulness as biomarkers of Cd exposure. According to urinary Cd concentration, the subjects were divided into four groups (urinary Cd concentration ≥0.1 µg/g.Cr, ≥1.0 µg/g.Cr, ≥5.0 µg/g.Cr and ≥50.0 µg/g.Cr). Subjects exhibited increased severe health problems with higher urinary Cd concentrations. The eIF3 and eEF-1δ expression in the blood were investigated with real-time PCR. PCR data showed a strong positive correlation between blood eEF-1δ and urinary Cd concentrations (r = 0.788, p < 0.01), and a weak positive correlation between blood eIF3 expression and urinary Cd concentrations (r = 0.569, p < 0.05). These findings, for the first time, demonstrate that the blood eEF-1δ overexpression can be used as a molecular biomarker of Cd-exposed population.