The Alchemist’s Approach to Metal Poisoning: Transforming the Metal Burden

Co-supplementation of Zinc and Calcium Suppresses Bio-absorption of Lead in Sprague Dawley Rats

Lead (Pb) is a widespread environmental toxicant and its toxicity causes huge health impacts. The present study was conducted to examine the protective role of zinc (Zn) and calcium (Ca) supplements against bio-absorption of Pb in blood and organs including the liver and kidney. Hence, Sprague Dawley rats were divided in to five groups. G₁ served as negative control and was provided with standard diet, G₂ as positive control receiving standard diet + PbAc (20 mg/kg BW), G₃ was provided with standard diet + PbAc (20 mg/kg BW) + ZnSO₄ (20 mg/kg BW), G₄ with standard diet + PbAc (20 mg/kg BW) + CaCO₃ (7.5 g/kg BW) whereas G₅ was fed on standard diet + PbAc (20 mg/kg BW) + ZnSO₄ (20 mg/kg BW) + CaCO₃ (7.5 g/kg BW). The salts were provided as solution, dissolved in 0.5 mL distilled water via orogastric tube. After 35 days, the overnight fasted rats were decapitated, and blood and organs were collected for analysis of levels of metals and liver and kidney function tests. The results depicted significant decrease in Pb concentration in blood and organs while increase in Zn and Ca absorption was observed as a result of Zn and Ca supplementation with Zn being better than Ca alone, specially however, combined effect of these supplements was more profound in improving liver and kidney stress biomarkers and maintained the normal architecture of renal and hepatic parenchyma. It was concluded that Zn and Ca co-supplementation hinder Pb absorption in blood, the liver, and kidney thus suggesting that their intake may protect from Pb toxicity.

Assessment of Concentrations of Heavy Metals in Postmyocardial Infarction Patients and Patients Free from Cardiovascular Event

Cardiovascular diseases (CVDs) constitute the first cause of death among the population of developing and developed countries. Atherosclerosis, which is a disorder with multifactorial etiopathogenesis, underlies most CVDs. The available literature includes ample research studies on the influence of classic cardiovascular (CV) risk factors. However, environmental exposure to heavy metals, among other substances, is still an unappreciated risk factor of CVDs. This study aimed to assess the concentration of some heavy metals (copper (Cu), zinc (Zn), manganese (Mn), cobalt (Co), and iron (Fe)) in the blood serum of postmyocardial infarction (post-MI) patients and patients free from myocardial infarction (MI) as well as estimate the relationship between the occurrence of MI and increased concentration of heavy metals. The concentration of heavy metals (Cu, Zn, Mn, Co, and Fe) was assessed using the inductively coupled plasma mass spectrometry technique in a group of 146 respondents divided into two groups: post-MI group (study group (SG), n = 74) and group without cardiovascular event (CVE) having a low CV risk (control group (CG), n = 72). The concentration of the analyzed heavy metals was higher in SG. All the heavy metals showed a significant diagnostic value (p < 0.001). The highest value of area under the curve (AUC) was observed for manganese (Mn) (0.955; 95% confidence interval (CI) = 0.922–0.988), while the lowest value was found for zinc (Zn) (0.691; 95% CI = 0.599–0.782). In one-dimensional models, high concentrations of each of the analyzed heavy metals significantly increased the chances of having MI from 7-fold (Cu) to 128-fold (Mn). All the models containing a particular metal showed a significant and high discrimination value for MI occurrence (AUC 0.72–0.92). Higher concentrations of Cu, Zn, Mn, Co, and Fe were found to considerably increase the chances of having MI. Considering the increasingly higher environmental exposure to heavy metals in recent times, their concentrations can be distinguished as a potential risk factor of CVDs.

Changes in the brain antioxidant profile after chronic vanadium administration in mice

Vanadium is known to induce reactive oxygen species (ROS) in biological systems. Exposure to vanadium has been linked to neurological defects affecting the central nervous system (CNS) early in life and culminates later to neurodegeneration. This study was designed to evaluate the effects of chronic vanadium exposure on antioxidant profile in mice, and progressive changes after withdrawal from treatment. A total of 85 male BALB/c mice (4 weeks old) were used for the experiment and were divided into three groups of vanadium exposed (3 mg/kg i.p at 3-18 months treatment), matched controls, and animals exposed to vanadium for three months and thereafter vanadium was withdrawn. Vanadium exposure caused significant increases (p<0.05) in levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂) generation and nitric oxide with a concomitant decrease (p<0.05) in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-S-transferase and a decline in the level of reduced glutathione (GSH) after 6 months of vanadium exposure in the brain. This trend continued in all vanadium-exposed groups (9, 12, 15 and 18 months) relative to the matched controls. Withdrawal after 3 months of vanadium exposure significantly reversed oxidative stress in intoxicated mice from 9 to 15 months after vanadium withdrawal. We have shown that chronic administration of vanadium led to oxidative stress in the brain which is reversible only after a long period of vanadium withdrawal.

Heavy Metals and Human Health: Mechanistic Insight into Toxicity and Counter Defense System of Antioxidants

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.