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Metais e sistema hepático: efeitos adversos e potencialidades em diagnóstico e terapêutica
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Abstract(s)
O fígado é considerado um órgão de extrema importância no nosso organismo por todas as funções que desempenha, como a metabolização e excreção dos fármacos e metais. Assim sendo é muito importante conhecer como e em que condições os metais podem provocar hepatoxicidade, seja pelo desequilíbrio da quantidade dos metais normalmente presentes no organismo, seja pela administração de metais incorporados em fármacos para diagnóstico ou tratamento.
No caso da deficiência de metais com influência sobre o fígado, refere-se a anemia ferropénica por deficiência em Fe e a síndrome de Menkes por deficiência em Cu. Em excesso, a hemocromatose causada pelo Fe e a cirrose indiana infantil e a doença de Wilson provocadas pelo Cu. O reestablecimento do equilíbrio nestes casos é obtido através da administração dos metais em falta ou da quelatação com posterior remoção, consoante o caso.
Os metais têm um papel importante quer na imagiologia do fígado quer como potenciais agentes terapêuticos do carcinoma hepatocelular. Na imagiologia do fígado, são utilizados na ressonância magnética nuclear e na tomografia computadorizada por emissão de fotão único, e devem permitir a análise sem que exista acumulação que pode levar a efeitos secundários indesejados. Na terapêutica, diversos metais (na forma de nanopartículas) têm demonstrado potencial no tratamento de um dos cancros mais severos, considerado em 2000 a terceira causa de morte por cancro.
Neste âmbito, o presente trabalho centrou-se na análise bibliográfica da influência de metais, em particular de metais de transição, no fígado. Inclui a abordagem de patologias devido a excesso ou deficiência de metais específicos e em que o fígado tem um papel importante e o uso de fármacos com base em metais de transição, quer com ação terapêutica quer de diagnóstico, direcionados a este órgão.
The liver is a very important organ in the body due to the functions it performs. It is responsible for drug metabolism and metals excretion and, it is then of paramount importance to understand how the metals may exert hepatoxicity, either by the unbalance of those normally present in the body or by metal incorporation in drugs for diagnosis or treatments. In the case of deficiency of metals with influence on the liver, it is described the Fe deficiency that results in anemia and Menkes syndrome resulting from the deficiency in Cu. In excess, hemochromatosis caused by Fe and indian childhood cirrhosis and wilson's disease caused by Cu. Providing the missing metals or quelation of metals that are in excess using adequate drugs, are the usual therapeutic ways to restore the metals balance in the body. Metals also play an important role both in liver imaging and as potential drugs for the treatment of the hepatocellular carcinoma. Concerning the liver imaging, metals are used in magnetic resonance imaging and computed tomography single photon emission tomography. They should allow the imaging without being irreversibly accumulated, which could result in undesired side effects. Several metals (in the form of nanoparticles) have also shown interesting potential as drugs for the treatment of hepatocellular carcinoma, one of the most serious cancers that was identified in 2000 as the third leading cause of death by cancer. In this context, the present work aims at the bibliographical analysis of the influence of metals, in particular of transition metals, in the liver. It includes the pathologies due to excess or deficiency of specific metals and in which the liver has an important role, and the use of drugs based on transition metals, either with therapeutic or diagnostic action, directed to this organ.
The liver is a very important organ in the body due to the functions it performs. It is responsible for drug metabolism and metals excretion and, it is then of paramount importance to understand how the metals may exert hepatoxicity, either by the unbalance of those normally present in the body or by metal incorporation in drugs for diagnosis or treatments. In the case of deficiency of metals with influence on the liver, it is described the Fe deficiency that results in anemia and Menkes syndrome resulting from the deficiency in Cu. In excess, hemochromatosis caused by Fe and indian childhood cirrhosis and wilson's disease caused by Cu. Providing the missing metals or quelation of metals that are in excess using adequate drugs, are the usual therapeutic ways to restore the metals balance in the body. Metals also play an important role both in liver imaging and as potential drugs for the treatment of the hepatocellular carcinoma. Concerning the liver imaging, metals are used in magnetic resonance imaging and computed tomography single photon emission tomography. They should allow the imaging without being irreversibly accumulated, which could result in undesired side effects. Several metals (in the form of nanoparticles) have also shown interesting potential as drugs for the treatment of hepatocellular carcinoma, one of the most serious cancers that was identified in 2000 as the third leading cause of death by cancer. In this context, the present work aims at the bibliographical analysis of the influence of metals, in particular of transition metals, in the liver. It includes the pathologies due to excess or deficiency of specific metals and in which the liver has an important role, and the use of drugs based on transition metals, either with therapeutic or diagnostic action, directed to this organ.
Description
Keywords
Fígado Hepatotoxicidade Metais Imagiologia Quimioterapia Carcinoma hepatocelular Metais e sistema hepático Efeitos adversos e po