Proteinuria mercury exposure

Renal damage has been reported after both acute and chronic exposure. Mercury is known to accumulate in the kidneys, and case studies have described increased creatinine excretion, proteinuria, hematuria, and degeneration of the convoluted tubules in exposed individuals. Increased levels of the urinary enzyme NAG (AT-acetyl-P-glycosaminidase), compared with controls, have been observed in chronically exposed workers. ... 

The kidney is the primary target organ for Hg2+. Chronic exposure to inorganic mercury ) compounds causes proteinuria. In cases of mercury poisoning of any type, the kidney is the organ with the highest bioaccumulation of mercury. 

The association between metal exposure and renal failure can be approached from two points of view. On the one hand environmental/industrial exposure to heavy metals, more particularly, lead, cadmium and mercury and other inorganic substances such as silicon has been linked to a reduced renal function and/or the development of acute or chronic renal failure [1]. This issue has been dealt with in other chapters of this book. On the other hand patients with chronic renal failure, especially those treated by dialysis are at an increased risk for trace element disturbances (Figure 1). Indeed in these subjects the reduced renal function, the presence of proteinuria, metabolic alterations associated with renal insufficiency, the dialysis treatment, medication etc. all may contribute to either accumulation or deficiency of trace metals. With regard to aluminum intensive research on the element s toxic effects has been performed in the past. Recently, new metal-containing medications have been introduced of which the potential toxic effects should be considered and put in a justified context. 

The results of studies in humans on the immune reaction to elemental mercury vapor exposure have been inconsistent, with either increases or decreases in immune activity. In workers exposed occupationally to mercury vapor, a stimulation of T-lymphocytes, manifested by an increased number of T cells, T-helper cells and T-suppressor cells, was observed (Moszczynski et al. 1995). Further, a reduction in the number of B lymphocytes as of CD4+ lymphocytes in T cells was found in mercury vapor-exposed workers and, on the other hand, increased immunoglobulin E levels (Dantas and Queiroz 1997). Renal biopsies of two mercury-exposed workers who had developed proteinuria revealed deposits if IgG and complement C3 in the glomeruli (Tubbs et al. 1982). High anti-DNA antibody titers have been reported... 

Chronic exposure to mercury vapor occurs in the workplace. The classic triad of symptoms involves the oral cavity (gingivitis, salivation, stomatitis), tremor, and psychological changes. Central nervous system symptoms observed in workers exposed to mercury vapor are termed erethism, which includes insomnia, loss of appetite, pathological shyness, emotional lability, irritability, and memory loss. Renal dysfunction as determined by urinalysis has been observed in workers exposed to mercury vapor. Both glomerular (proteinuria) and tubular (enhanced excretion of tubular enzymes) effects have been reported. 

Zalups RK, Barfuss D (1990) Accumulation of inorganic mercury along the renal proximal tubule of the rabbit. Toxicol Appl Pharmacol 106 245-253 Zalups RK, Lash LH (1990) Effect of uninephrectomy and mercuric chloride on renal glutathione homeostasis. J Pharmacol Exp Ther 254 962-970 Zhao JY, Wang SJ (1988) Experimental study of proteinuria caused by chronic exposure to mercury. Biomed Environ Sci 1 235-246... 

---