While it’s long been known that the industrially important metal cadmium is toxic, the exact mechanisms behind the toxicity and the accompanying cellular damage has remained something of an unknown. New research from the University of Adelaide is now changing this though.
Considering that cadmium has been accumulating in the food chain over recent decades — mostly owing to industrial activity — the work is notable, and may perhaps lead to more effective treatment options.
To put it in a somewhat oversimplified wording, cadmium interferes with cellular metal sensing machinery — leading to the disputed transport (in and out of cells) of essential metals such as zinc and manganese, as well as other problems.
“Cadmium is a very important industrial metal, but exposure to it results in accumulation in the food chain, leading to toxicity in animals and humans,” stated project leader Dr Christopher McDevitt, Senior Research Fellow and Deputy Director of the University’s Research Centre for Infectious Diseases.
Exposure to cadmium can occur due to poor disposal of industrial or electronics waste, and also through cigarette smoke and ingestion of contaminated food. While the toxicity of cadmium has been known for a long time, how it causes toxicity and damages cells hasn’t been understood.
We’ve shown, in a model bacterial system, that the chemistry of cadmium allows it to bypass the mechanisms that prevent other metals, such as iron and zinc, from freely entering cells. Once inside the cell, cadmium inserts itself into the cell’s metal sensing machinery causing it to malfunction and pump out the wrong metal ions while still bringing in more cadmium. This ultimately leads to death of the cell.
This understanding of how cadmium causes toxicity, at a molecular level, is crucial for developing new strategies for preventing cadmium poisoning.
Considering the modern ubiquity of cadmium — cadmium production has surged 1000-fold since the early 1900s — gaining a better understanding of its toxicity would seem to be expedient. Cadmium is currently used in all manner of electronics, including common forms of energy storage/batteries and First Solar‘s solar panels. Many of these products are improperly disposed of, and end up leaching toxic metals and compounds into the soil and water where they are “disposed” of.
Current estimates are that the “average” human ingests up to 30 micrograms of cadmium a day. This figure is of course higher in the regions where electronic waste is commonly dumped or sent — West Africa, in particular, comes to mind.
“Cadmium isn’t used in biological systems (with one rare exception) which means that cells haven’t evolved ways to deal with this metal when they encounter it,” stated Dr McDevitt. “Our findings here open the way for developing new therapies for preventing cadmium toxicity.”
The new research was just published in the journal Nature Communications.
Image Credit: Public Domain
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