The increasing use of lanthanum (La) in information technology hardware has resulted in a related increase in environmental pollution. Recently, La-carbonate has been introduced as an effective phosphate-binder to reverse hyperphosphatemia due to chronic kidney disease. However, it is uncertain whether long-term treatment with La-carbonate is safe. Our previous study found accumulation of La in mesangial cells and the basal lamina of the proximal tubules in rat kidneys (Daimon, 2006). The aims of this study were to examine the effects of La on renal function and to assess La toxicity. Rats received La-chloride (2.5 mg La/body weight/week) intravenously for 5 weeks. Creatinine, blood urea nitrogen (BUN), and protein levels were measured in plasma using an automated chemical analyzer. A complete blood count (CBC) was performed using an automatic CBC counter for experimental animals. No differences in creatinine, BUN, and protein levels were seen between the experimental and control groups. These biochemical data indicate that La loading does not have any adverse effects on kidney function. La had no effects on the erythrocyte count, white blood cell count, platelet count, hemoglobin, or hematocrit. No degenerative features were seen on light microscopy in the kidney after La administration for 5 weeks, although La accumulation was seen in the proximal tubular cells, mesangial cells, and interstitial macrophages. In conclusion, the present biochemical and morphological findings confirm that exposure to La for 5 weeks is apparently safe and has no deleterious effects on rat kidney. However, the effects of chronic La exposure must be explored carefully, since the kidney is the primary target organ for La accumulation.

View full abstract