Harmful Interactions of Non-Essential Heavy Metals with Cells of the Innate Immune System

Abstract

In trace amounts, some heavy metals are essential for optimum health, while exposure to others, which are non-essential, presents the potential hazard of acute or chronic organ toxicity. Cadmium, mercury, lead, vanadium, platinum and palladium are commonly encountered, non-essential heavy metals which mediate their toxic activities by various mechanisms. All have the potential to interact with extracellular and intracellular protein sulfhydryls, rendering them not only potentially allergenic, but also predisposing to oxidative stress, while displacement of essential elements from their protein carriers may result in deficiency disorders. In addition, several of these metals, especially cadmium, palladium, platinum, and vanadium interact pro-oxidatively with the phagocytic cells of the innate immune system, potentiating the reactivity and toxicity of phagocyte-derived reactive oxygen species. This review is focused on the pro-oxidative/pro-inflammatory interactions of non-essential heavy metals with the cells of the innate immune system, a somewhat under-appreciated mechanism of metal induced toxicity.