The role of thiols, dithiols, nutritional factors and interacting li
Posted by:
Fri Dec 14, 2007 7:38 pm (PST)
Hi all,

I was searching for something and came accross this article. It is
interesting that they mention ALA and can be used as a chelator "when
used in an appropriate manner".

The role of thiols, dithiols, nutritional factors and interacting
ligands in the toxicology of mercury.
http://www.ncbi.nlm.nih.gov/sites/e...DetailView&TermToSearch=17408840

A couple of items of interest that I wonder if an expert can chime in
on.

"Whilst N-acetyl-cysteine (NAC) and glutathione (GSH) have been
recommended in the treatment of mercury toxicity in the past, an
examination of available evidence suggests these agents may in fact
be counterproductive."

Ok, given that neither of these are a chelator this seems right.
Though I thought that GSH was involved in clearing cells of heavy
metals.

"Evidence suggests however that the co-administration of selenium and
dithiol chelation agents during treatment may also be counter-
productive."

This last one interested me the most. Any thoughts on this?

Anyone have access to the whole article? I'd like to read it.

Thanks,
Mike

Mercury has been a known as a toxic substance for centuries. Whilst the clinical features of acute mercury poisoning have been well described, chronic low dose exposure to mercury remains poorly characterised and its potential role in various chronic disease states remains controversial. Low molecular weight thiols, i.e. sulfhydryl containing molecules such as cysteine, are emerging as important factors in the transport and distribution of mercury throughout the body due to the phenomenon of "Molecular Mimicry" and its role in the molecular transport of mercury. Chelation agents such as the dithiols sodium 2,3-dimercaptopropanesulfate (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) are the treatments of choice for mercury toxicity. Alpha-lipoic acid (ALA), a disulfide, and its metabolite dihydrolipoic acid (DHLA), a dithiol, have also been shown to have chelation properties when used in an appropriate manner. Whilst N-acetyl-cysteine (NAC) and glutathione (GSH) have been recommended in the treatment of mercury toxicity in the past, an examination of available evidence suggests these agents may in fact be counterproductive. Zinc and selenium have also been shown to exert protective effects against mercury toxicity, most likely mediated by induction of the metal binding proteins metallothionein and selenoprotein-P. Evidence suggests however that the co-administration of selenium and dithiol chelation agents during treatment may also be counter-productive. Finally, the issue of diagnostic testing for chronic, historical or low dose mercury poisoning is considered including an analysis of the influence of ligand interactions and nutritional factors upon the accuracy of "chelation challenge" tests.