Biomarkers of early vascular endothelial injury with low-arsenic exposure in drinking water

Objective To observes the change of early effective biomarkers of endothelial injury with lowarsenic exposure in drinking water. Methods Ninety rurad residents, who had lived in Yanhe village, Xuyi county and Jiangsu province for at least 10 years, were recruited by simple random sampling in this study. The level of arsenic in their household shallow well were divided into three groups, which were ＜ 10 (32 people), 10 - 50(28 people) and ＞ 50 μg/L(30 people). Blood samples from individuals were collected. Malondialdehyde(MDA) in human plasma, which is considered as the most important marker for monitoring lipid peroxidation, was determined as conjugate with tetrabutylammonium hydrogen sulphate(TBA). The level of anti-superoxide anion radical(O-·2),C-reactive protein(CRP) and NO in human plasma was measured with colorimetry, turbidimetry and nitric acid reductase, respectively. The number of circulating endothelial progenitor cells(CEPCs) in peripheral blood was analyzed by CD133+/KDR+ antibodies and flow cytometry. Results Ninety cases underwent questionnaires. Between the groups, the difference of the levels of MDA (61.1, 65.5, 67.5 μmol/kg), O-·2 (4774.6, 5143.3, 4736.0 U/kg) ,CRP[(5.92 ± 2.44), (5.11 ± 2.40), (5.55 ± 2.96)mg/L], and NO[(659.8 ± 387.5), (667.4 ± 486.6), (762.1 ±763.2)μmol/kg], was not statistically significant (F =0.00, 0.46, 0.80, 0.47, all P ＞ 0.05). The difference of the number of CEPCs in different groups of arsenic in drinking water was statistically significant(0.96 x 10-5, 0.77 x 10-5,1.59 x 10-5, F=5.08, P＜ 0.05), where ＜ 10, 10 - 50 μg/L groups were significantly lower than ＞ 50 μg/L group (q =4.58, 6.65, all P ＜ 0.05). Conclusions The number of CEPCs in peripheral blood changes significantly with lower-arsenic exposure, whereas there are no obvious changes with the markers of oxidized damage and inflammation. This is the first human demonstration showing that lower-arsenic exposure may cause endothelial injury. Key words: Arsenic ;  Endothelium, vascular;  Circulating endothelial progenitor cells;  Biomarkers