The team behind the new study, which is published in The FASEB Journal, revealed that drops in blood zinc levels so not directly harm blood vessels. Rather, the UK-based research team found that zinc regulates the production of a low molecular weight factor which then circulates in the blood and causes harmful blood vessel cell effects.
"We proposed that a zinc-regulated humoral factor might mediate the effects of zinc deprivation," said the research team - led by Professor John Beattie of the Rowett Institute at the University of Aberdeen. "Zinc deficiency induces the production of a low-molecular-weight humoral factor whose influence on vascular smooth muscle cells gene expression is blocked by plasma zinc. This factor is therefore under dual control by zinc."
"Measurement of this compound in blood may prove very valuable, not only in assessing, for example, the risk of developing heart attack or stroke, but also as a diagnostic test for zinc status," said Beattie.
Beattie and colleagues grew cells from rat blood vessels and exposed them for 24 hours to the blood plasma from rats that had been given food that was either low or adequate in zinc. The team then examined gene expression profiles to identify which genes changed when exposed to blood plasma from low zinc rats.
They found dramatic changes in the activity of some gene, with more than 2,500 genes expression changes in 'deficient' cells when compared to incubation of cells with zinc-adequate blood plasma.
By removing the zinc from the 'adequate' plasma and testing this in a third set of the team found that a simple absence of zinc had no effect on gene expression - so suggesting that there was another compound produced in response to zinc deficiency and that this is what causes negative effects.
"We demonstrated that this effect was caused by a low-molecular-weight (∼2-kDa) zinc-regulated humoral factor but that changes in gene expression were mostly reversed by adding zinc back to zinc-deficient plasma," said Beattie and his team.
"Most people might think of zinc as a kind of food supplement," commented Dr Gerald Weissmann, , editor-in-chief of The FASEB Journal, "but zinc deficiency is a serious matter."
"Understanding how zinc deficiency affects the body is important, not just because it can help us how to treat this deficiency, but also because it presents a new way to detect low zinc in the body that is faster and easier than current methods."
Source: The FASEB Journal
Volume 27, Number 9, Pages 3672-3682, doi: 10.1096/fj.13-228791
"Plasma zinc's alter ego is a low-molecular-weight humoral factor"
Authors: Ou Ou, Keith Allen-Redpath, Dagmar Urgast, Margaret-Jane Gordon, et al