Accumulation of cadmium in insulin-producing beta cells

作者：El Muayed Malek^*; Raja Meera R; Zhang Xiaomin; MacRenaris Keith W; Bhatt Surabhi; Chen Xiaojuan; Urbanek Margrit; O'Halloran Thomas V; Lowe William L Jr

来源：Islets, 2012, 4(6): 405-416.

DOI：10.4161/isl.23101

• cadmium
• zinc transporters
• metallothionein
• insulin secretion
• beta cells

Evidence suggests that chronic low level cadmium exposure impairs the function of insulin-producing beta cells and may be associated with type-2 diabetes mellitus. Herein, we describe the cadmium content in primary human islets and define the uptake kinetics and effects of environmentally relevant cadmium concentrations in cultured beta cells. The average cadmium content in islets from 10 non-diabetic human subjects was 29 +/- 7 nmol/g protein (range 7 to 72 nmol/g protein). Exposure of the beta-cell line MIN6 to CdCl2 concentrations between 0.1 and 1.0 mu mol/L resulted in a dose-and time-dependent uptake of cadmium over 72 h. This uptake resulted in an induction of metallthionein expression, likely enhancing cellular cadmium accumulation. Furthermore, cadmium accumulation resulted in an inhibition of glucose stimulated insulin secretion in MIN6 cells and primary mouse islets. Our results indicate that this impairment in beta-cell function is not due to an increase in cell death or due to an increase in oxidative stress. We conclude that mouse beta cells accumulate cadmium in a dose-and time-dependent manner over a prolonged time course at environmentally relevant concentrations. This uptake leads to a functional impairment of beta-cell function without significant alterations in cell viability, expression of genes important for beta-cell function or increase in oxidative stress.

• 出版日期2012-12
• 单位西北大学