Lead and Heavy Metals and the Kidney

Heavy metals are used in industrial applications, such as production of pesticides, batteries, alloys, and textile dyes. Excessive exposure may lead to specific disorders. The kidney is a target organ in heavy metal toxicity because of its ability to reabsorb and concentrate divalent metals. The extent of renal damage depends on the nature, the dose, and the time of exposure. In general, acute damage differs from chronic damage in its mechanism of toxicity. As a consequence, the clinical features and therapeutic approach are also different. Heavy metals in plasma exist in nondiffusible and ionized forms. The ionized form is toxic and produces acute toxicity; on the other hand the bound, inert form is conjugated with metallothionein and glutathione, which then are released into the blood by the liver and the kidney. These compounds subsequently are reabsorbed through an endocytotic process in segment S1 of the proximal tubule and can lead to chronic damage. Treatment regimens include chelation therapy, decontamination procedures, supportive care, and extracorporeal therapy. This chapter adds specific considerations for some of the most common metals.