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Mecanismos de toxicidade do cobalto, níquel e manganês: da exposição e homeostasia às suas interações com os lípidos e as biomembranas
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Os metais essenciais cobalto (Co), níquel (Ni) e manganês (Mn) desempenham funções vitais no organismo humano, atuando como cofatores em múltiplas reações enzimáticas envolvidas na sinalização celular, metabolismo energético e resposta ao stress oxidativo. No entanto, desequilíbrios na sua homeostase, seja por carência ou por exposição crónica, podem conduzir a efeitos adversos significativos para a saúde. O cobalto tem sido implicado em quadros de cardiomiopatia, lesões pulmonares e ototoxicidade; o níquel destaca-se pelo seu potencial carcinogénico e elevado poder sensibilizante; já o manganês apresenta reconhecida neurotoxicidade, estando associado a um quadro clínico semelhante à doença de Parkinson, designado por “manganismo”. Uma área ainda pouco explorada diz respeito à interação destes metais com os lípidos e as membranas biológicas, estruturas fundamentais à integridade e funcionalidade celular, e que se revelam potenciais alvos críticos da toxicidade metálica. Neste contexto, a presente dissertação assume a forma de uma revisão narrativa da literatura, tendo como objetivo central analisar de forma integrada os dados mais recentes sobre a toxicidade do Co, Ni e Mn, abrangendo aspetos como a exposição humana, os mecanismos de homeostase e transporte, os principais alvos moleculares e, com especial destaque, as suas interações com os lípidos e biomembranas. A análise dos estudos científicos disponíveis permitiu concluir que estes metais, quando em excesso, comprometem de forma significativa a integridade das membranas celulares, promovem alterações no metabolismo lipídico e desencadeiam processos de peroxidação lipídica, com impacto relevante na função mitocondrial e na indução de stress oxidativo. Estes processos estão intimamente ligados à fisiopatologia de várias doenças crónicas, nomeadamente patologias cardiovasculares, neurodegenerativas e oncológicas. Em simultâneo, constatou-se que as abordagens terapêuticas atuais, nomeadamente os agentes quelantes, continuam a apresentar limitações em termos de seletividade e eficácia, sendo necessária a investigação de estratégias mais direcionadas, que integrem a modulação da interação metal-membrana como alvo terapêutico.
The essential metals cobalt (Co), nickel (Ni), and manganese (Mn) play vital roles in the human body, acting as cofactors in numerous enzymatic reactions involved in cellular signaling, energy metabolism, and response to oxidative stress. However, imbalances in their homeostasis, whether due to deficiency or chronic exposure, can lead to significant adverse health effects. Cobalt has been implicated in cardiomyopathy, pulmonary injury, and ototoxicity. Nickel is known for its carcinogenic potential and strong sensitizing capacity. Manganese is a recognized neurotoxicant, associated with a clinical condition resembling idiopathic Parkinson’s disease, known as “manganism”. One area still underexplored concerns the interaction of these metals with lipids and biological membranes, which are fundamental to cellular structure and function and represent potential critical targets of metal-induced toxicity. In this context, the present dissertation adopts the format of a narrative literature review, aiming to provide an integrated analysis of the most recent findings on Co, Ni, and Mn toxicity. It explores various aspects including human exposure, homeostasis and transport mechanisms, major molecular targets, and, with particular emphasis, their interactions with lipids and biomembranes. Analysis of the available scientific literature reveals that excessive levels of these metals significantly compromise membrane integrity, induce alterations in lipid metabolism, and trigger lipid peroxidation processes. These effects have a marked impact on mitochondrial function and are strongly associated with oxidative stress induction. Altogether, these mechanisms are closely linked to the pathophysiology of several chronic diseases, including cardiovascular, neurodegenerative, and oncological disorders. Also, current therapeutic approaches, particularly chelating agents, remain limited in terms of selectivity and efficacy. This underscores the need for more targeted strategies that consider the modulation of metal-membrane interactions as a therapeutic target.
The essential metals cobalt (Co), nickel (Ni), and manganese (Mn) play vital roles in the human body, acting as cofactors in numerous enzymatic reactions involved in cellular signaling, energy metabolism, and response to oxidative stress. However, imbalances in their homeostasis, whether due to deficiency or chronic exposure, can lead to significant adverse health effects. Cobalt has been implicated in cardiomyopathy, pulmonary injury, and ototoxicity. Nickel is known for its carcinogenic potential and strong sensitizing capacity. Manganese is a recognized neurotoxicant, associated with a clinical condition resembling idiopathic Parkinson’s disease, known as “manganism”. One area still underexplored concerns the interaction of these metals with lipids and biological membranes, which are fundamental to cellular structure and function and represent potential critical targets of metal-induced toxicity. In this context, the present dissertation adopts the format of a narrative literature review, aiming to provide an integrated analysis of the most recent findings on Co, Ni, and Mn toxicity. It explores various aspects including human exposure, homeostasis and transport mechanisms, major molecular targets, and, with particular emphasis, their interactions with lipids and biomembranes. Analysis of the available scientific literature reveals that excessive levels of these metals significantly compromise membrane integrity, induce alterations in lipid metabolism, and trigger lipid peroxidation processes. These effects have a marked impact on mitochondrial function and are strongly associated with oxidative stress induction. Altogether, these mechanisms are closely linked to the pathophysiology of several chronic diseases, including cardiovascular, neurodegenerative, and oncological disorders. Also, current therapeutic approaches, particularly chelating agents, remain limited in terms of selectivity and efficacy. This underscores the need for more targeted strategies that consider the modulation of metal-membrane interactions as a therapeutic target.
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Cobalto Níquel Manganês Toxicidade metálica Homeostase Biomembranas Lípidos Metabolismo lipídico Stress oxidativo Cobalt Nickel Manganese Metal toxicity Homeostasis Biomembranes Lipids Lipid metabolism Oxidative stress