Effects of Mercury, Lead, Arsenic and Zinc to Human Renal Oxidative Stress and Functions: A Review

Abstract

Background: Heavy metals such as mercury (Hg), lead (Pb) and arsenic (As) are elements that promote the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) involved in the etiology of oxidative stress. They cause oxidative damage to membrane lipids, proteins and DNA, thereby activating pathways of apoptosis and tissue degeneration. Some chemical species derived from these metals include methyl mercury (CH3Hg+), tetraethyl lead [(CH3CH2)4Pb], arsenate (AsO43-) and arsenite (AsO2-), all of which have the capacity to induce oxidative stress and renal damage. Purpose: To comprehensively review the effects of Hg, Pb, As and Zinc (Zn) on renal oxidative status. Methods: Literature survey was done using key words such as heavy metals, oxidative stress and kidney damage using search engines for free scientific publications such as PubMed database, FreeFullPDF.com and Google Scheler. Results: It was revealed that Hg, Pb and As contribute significantly to oxidative stress by stimulating the generation of free radicals, oxidation of biomolecules, deregulation of pro-oxidant proteins, and activation of pro-inflammatory molecules, which ultimately lead to renal damage. There is a strong association between exposure to these heavy metals and chronic renal damage, since their bioaccumulation deregulates glomerular filtration and tubular secretion due to excessive production of ROS and activation of apoptotic pathways. However, studies have shown that Zn possesses renoprotective and antioxidant effects, and its deficiency leads to oxidative stress. Conclusion: The results of this survey suggest that deficiencies of Hg, Pb, As and Zn produce different degrees of oxidative damage which negatively impact on renal health.