Association of liver and kidney functions with Klotho gene methylation in a population environment exposed to cadmium in China

Abstract

Exposure to the heavy metal cadmium has adverse effects on human health, including DNA methylation. This study aimed to investigate the effects of cadmium on liver and kidney functions and <i>Klotho</i> gene methylation and to explore the relationship of methylation level with indicators of liver and kidney functions. Graphite furnace atomic absorption spectrometry was conducted to determine urinary cadmium, and an automatic biochemical analyzer was used to detect indices of liver and kidney functions. PCR pyrosequencing was performed to detect the methylation rate of Klotho. One-way ANOVA was adopted to compare the differences between groups, and the linear correlation to variables was analyzed. Cadmium exposure was negatively correlated with albumin level (r=-0.143, <i>p</i>=0.021) and positively correlated with urinary β₂-microglobulin level (r=0.229, <i>p</i><0.001). However, the methylation levels of <i>Klotho</i> gene was decreased and increased by low and high doses of cadmium exposure, respectively. And <i>Klotho</i>methylation levels were negatively correlated with albumin levels and positively correlated with β₂-microglobulin levels.In this study, cadmium exposure affects liver and kidney functions as well as <i>Klotho</i> methylation levels, but the effect on <i>Klotho</i> methylation levels is not linear. <i>Klotho</i> methylation levels also influence liver and kidney functions.