Biomedical implications of heavy metals induced imbalances in redox systems (original) (raw)
Related papers
Reactive molecules and free radicals are used to define the reactive oxygen species that include superoxide, hydrogen peroxide, hydroxyl radical, hydroxyl ion, and nitric oxide. Antioxidants are responsible to eradicate the ROS in the human body. Antioxidant systems of the cell lessen the perturbations whereas oxidative stress is the result of when re-active oxygen species production exceeds the limit and overcome the cellular antioxidants which disturb the cell signal-ing and gene regulation systems. Only antioxidants can prevent or delay the oxidation of cellular oxidizable substrates. Heavy metals (Pb, Hg, Cd, Cr, Cu, Zn, Mn, Ni, Ag, etc.) are dangerous to human health; they enter into human body via food, drinking water and air. These heavy metals' toxicity causes serious health issues and causes diseases in human body. High concentration of lead leads towards the complications in the synthesis of hemoglobin, renal effects, gastric and CNS disturbances. Mercury leads to abortion, congenital malformation and development changes in young children. Selenium cause fatigue and irritability, alopecia and fingernail loss, damage the renal, hepatic system. Anti-mony causes nausea, vomiting and diarrhea and cancer. Two mechanisms are involved in the production of superoxide firstly when ATP is not being produced by mitochondria, simultaneously promotive forces become higher in concentration and decrease in coenzyme Q pool and secondly, the high ratio of NADH/NAD+ in mitochondrial matrix, skeletal muscle, heart and liver using different substrates and inhibitors to determine site for production of reactive oxygen species. NADPH oxidase and mitochondrial electron transport chain is responsible for the formation of cell reactive oxygen species in targeted pancreatic beta cell and other cells for insulin. Reactive oxygen species play many roles in ho-meostasis and on physiological levels, excess of it causes cellular stress and death. Due to accumulation of heavy metals many types of cancers occur like lung cancer, kidney cancer, brain cancer etc.
International Journal of Molecular Sciences, 2015
Heavy metals, which have widespread environmental distribution and originate from natural and anthropogenic sources, are common environmental pollutants. In recent decades, their contamination has increased dramatically because of continuous discharge in sewage and untreated industrial effluents. Because they are non-degradable, they persist in the environment; accordingly, they have received a great deal of attention owing to their potential health and environmental risks. Although the toxic effects of metals depend on the forms and routes of exposure, interruptions of intracellular homeostasis include damage to lipids, proteins, enzymes and DNA via the production of free radicals. Following exposure to heavy metals, their metabolism and subsequent excretion from the body depends on the presence of antioxidants (glutathione, α-tocopherol, ascorbate, etc.) associated with the quenching of free radicals by suspending the activity of enzymes (catalase, peroxidase, and superoxide dismutase). Therefore, this review was written to provide a deep understanding of the mechanisms involved in eliciting their toxicity in order to highlight the necessity for development of strategies to decrease exposure to these metals, as well as to identify substances that contribute significantly to overcome their hazardous effects within the body of living organisms.
Heavy metal associated health hazards: An interplay of oxidative stress and signal transduction
Chemosphere, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Toxic metals and antioxidants: Part II. The role of antioxidants in arsenic and cadmium toxicity
Alternative medicine review : a journal of clinical therapeutic, 2003
Exposure to toxic metals has become an increasingly recognized source of illness worldwide. Both cadmium and arsenic are ubiquitous in the environment, and exposure through food and water as well as occupational sources can contribute to a well-defined spectrum of disease. The symptom picture of arsenic toxicity is characterized by dermal lesions, anemia, and an increased risk for cardiovascular disease, diabetes, and liver damage. Cadmium has a significant effect on renal function, and as a result alters bone metabolism, leading to osteoporosis and osteomalacia. Cadmium-induced genotoxicity also increases risk for several cancers. The mechanisms of arsenic- and cadmium-induced damage include the production of free radicals that alter mitochondrial activity and genetic information. The metabolism and excretion of these heavy metals depend on the presence of antioxidants and thiols that aid arsenic methylation and both arsenic and cadmium metallothionein-binding. S-adenosylmethionine...
Oxidative Stress in Lead and Cadmium Toxicity and Its Amelioration
Veterinary Medicine International, 2011
Oxidative stress has been implicated to play a role, at least in part, in pathogenesis of many disease conditions and toxicities in animals. Overproduction of reactive oxygen species and free radicals beyond the cells intrinsic capacity to neutralize following xenobiotics exposure leads to a state of oxidative stress and resultant damages of lipids, protein, and DNA. Lead and cadmium are the common environmental heavy metal pollutants and have widespread distribution. Both natural and anthropogenic sources including mining, smelting, and other industrial processes are responsible for human and animal exposure. These pollutants, many a times, are copollutants leading to concurrent exposure to living beings and resultant synergistic deleterious health effects. Several mechanisms have been explained for the damaging effects on the body system. Of late, oxidative stress has been implicated in the pathogenesis of the lead- and cadmium-induced pathotoxicity. Several ameliorative measures ...
Effects of Mercury, Lead, Arsenic and Zinc to Human Renal Oxidative Stress and Functions: A Review
Journal of Heavy Metal Toxicity and Diseases, 2019
Heavy metals are metals with relatively high densities, atomic weights or atomic numbers, and include Hg, Pb, As, cadmium (Cd), nickel (Ni), chromium (Cr), Uranium (U) and thallium (Tl) [1,2]. Anthropogenic activities cause global contamination and pollution, the resultant health of which is heightened by the bioaccumulation of metal ions in the environment and in humans [3,4]. Most heavy metals at high concentrations exhibit harmful effects on the central nervous system (CNS), energy metabolism, ion transporters, cardiovascular system, respiratory system, reproductive system and vital organs such as lungs, liver, brain and kidney [5,6]. The combination of heavy metals with other xenobiotics such as pesticides exerts synergistic toxic effects on hematology and the immune system [7]. However, the degree of
Toxic Mechanisms of Five Heavy Metals: Mercury, Lead, Chromium, Cadmium, and Arsenic
Frontiers in Pharmacology, 2021
The industrial activities of the last century have caused massive increases in human exposure to heavy metals. Mercury, lead, chromium, cadmium, and arsenic have been the most common heavy metals that induced human poisonings. Here, we reviewed the mechanistic action of these heavy metals according to the available animal and human studies. Acute or chronic poisonings may occur following exposure through water, air, and food. Bioaccumulation of these heavy metals leads to a diversity of toxic effects on a variety of body tissues and organs. Heavy metals disrupt cellular events including growth, proliferation, differentiation, damage-repairing processes, and apoptosis. Comparison of the mechanisms of action reveals similar pathways for these metals to induce toxicity including ROS generation, weakening of the antioxidant defense, enzyme inactivation, and oxidative stress. On the other hand, some of them have selective binding to specific macromolecules. The interaction of lead with a...
Cellular pathologies and genotoxic effects arising secondary to heavy metal exposure: A review
Human & Experimental Toxicology, 2019
Environmental pollution is significant and oftentimes hazardous in the areas, where mining, foundries and smelters and other metallurgical operations are located. Systematic research on the chronic effects of metals started during the past century; nevertheless, it is evident that even today, there are large gaps in knowledge regarding the assessment of the health effects caused by environmental and occupational exposures to these metals. Heavy metals induce the production of reactive oxygen species (ROS) causing oxidative stress, make several repair-inhibiting cellular changes and alter the DNA repair processes. They favour the ‘false’ repairing of double-strand breaks (DSBs), propagate DNA mutations and induce carcinogenesis. A detailed literature search was performed using the MedLine/PubMed database. Depending on the mechanism of action, arsenicals can act as genotoxins, non-genotoxic agents and carcinogens. Cadmium can bind to proteins, reduce DNA repair, activate protein degra...