Metallothionein and Cadmium Toxicology—Historical Review and Commentary Original paper
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Metals
Metals
OverviewHeavy metals play a significant and multifaceted role in the pathogenicity of microbial species. Their involvement can be viewed from two primary perspectives: the toxicity of heavy metals to microbes and the exploitation of heavy metals by microbial pathogens to establish infections and evade the host immune response. Understanding these aspects is critical for both […]
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Divine Aleru
I am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
I am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
What was studied?
The study focused on cadmium (Cd) exposure and its toxicity, particularly the role of metallothionein (MT), a low-molecular-weight protein, in modulating the toxic effects of cadmium. The research explored how MT binds cadmium, preventing some toxic effects but also facilitating cadmium transport to sensitive organs like the kidneys. The work also investigated the influence of the Cd/Zn ratio in MT for toxicity expression in organs and the development of models for cadmium toxicokinetics to improve risk assessments.
Who was studied?
The research investigated both animal and human subjects to understand the effects of cadmium exposure and the role of metallothionein in mitigating cadmium toxicity. Specific focus was placed on occupational and environmental exposure groups, including those in artisanal small-scale mining, where uncontrolled cadmium exposure remains prevalent. The study involved experimental work on mice and data from humans exposed to cadmium, with emphasis on biomarkers such as MT gene expression in lymphocytes and MT autoantibodies in blood plasma.
Most important findings
The study established that metallothionein (MT) has a dual role in cadmium toxicity. While MT binding to cadmium can reduce some of the toxic effects, it can also increase the transport of cadmium to organs like the kidneys, where it causes damage. The research highlighted the importance of the Cd/Zn ratio within MT in expressing toxicity, particularly in the kidneys. The study found that MT gene expression and the presence of MT autoantibodies in human lymphocytes serve as biomarkers for assessing susceptibility to cadmium-related kidney dysfunction. The study also proposed a toxicokinetic model for cadmium exposure, which combines cadmium levels in tissues with risk assessments to predict health outcomes.
Key implications
The findings underscore the importance of metallothionein as both a protective mechanism and a mediator of cadmium toxicity, especially regarding kidney health. The study suggests that improving risk assessments by considering MT-related biomarkers could refine cadmium exposure evaluations and help prevent kidney and other organ-related diseases in exposed populations. Moreover, the study indicates that zinc status plays a critical role in modulating the risks of cadmium toxicity, with good zinc status mitigating kidney dysfunction risk. The growing global demand for metals underscores the urgency of improving preventive measures, particularly in regions with ongoing artisanal mining.
Cadmium (Cd) is a highly toxic heavy metal commonly found in industrial, agricultural, and environmental settings. Exposure to cadmium can occur through contaminated water, food, soil, and air, and it has been linked to a variety of health issues, including kidney damage, osteoporosis, and cancer. In agriculture, cadmium is often present in phosphate fertilizers and can accumulate in plants, entering the food chain. Its toxicity to living organisms makes cadmium a subject of regulatory concern worldwide, particularly in industrial waste disposal and environmental monitoring.