A total of 1,026 patients undergoing haemodialysis as the only chronic treatment were studied in all the dialysis units of the Veneto region, Italy. Aluminium was determined in water, dialysis fluids, and patients’ serum. Aluminium mean concentration was 9.1 µg/l in tap water and 13.3 and 15.7 µg/l in bicarbonate and acetate haemodialysis fluids, respectively. Patients’ serum aluminium mean level was 52.0 µg/l with the following frequency distribution: 59.2% below 60 µg/l, 25.5% between 60 and 100 µg/l, and 15.3% above 100 µg/l. The mean serum aluminium level was higher in patients undergoing haemodialysis with aluminium concentration in fluids over 10 µg/l. This was true also in patients not receiving aluminium hydroxide. Furthermore, we found higher average serum aluminium in those treated with aluminium hydroxide more than 3 g/day. No relationship was found between serum aluminium and sex, age, dialytic age, parathyroid hormone, and vitamin D treatment. Moreover, the patients with serum aluminium above 100 µg/l had higher serum alkaline phosphatase and lower mean cell volume values. Thus, in our haemodialysis population aluminium overloading occurred in spite of low concentration in water and fluid, and it was a result more of fluid pollution (over 10 µg/l) than aluminium hydroxide ingestion (over 3 g/day).

We investigated the best time of administration of desferrioxamine (DFO) with respect to the dialysis session, using the approach of the stochastic dynamic system, integrated with the classical pharmacokinetic models. In the 6 patients studied, the mean arrival times of DFO, aluminoxamine (AlO) and ferrioxamine (FO) were, respectively, 193, 1,350 and 126 min, the mean residence times were 1,048, infinite, 1,190 min, respectively. AlO serum levels reach steady state in a mean time of 7 h and 22 min and remain stable in the interdialytic period. FO achieves a peak at the end of DFO infusion and declines during the interdialytic period. DFO, AlO and FO persist a very long time in the body of the uremic patient, thus the dialysis session should be administered when AlO and FO reach steady state. With a dose of 5-10 mg/kg b.w. of DFO, we propose to start the dialysis 8-12 h after the infusion if the main purpose is to treat Al overload or 2-3 h after the infusion if the main purpose is the treatment of hemosiderosis.

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The concentration of aluminum (Al) in serum, urine, and bone, as well as bone histomorphometry parameters were studied before and 1 year after kidney transplantation (Tx) in 20 dialyzed patients. One year after Tx, serum Al fell significantly from 50.3 ± 8.8 to 23.9 ± 2.7 μg/l, (53% fall). Bone Al content also decreased significantly from 62.9 ± 9.0 to 36.5 ± 7.0 μg/kg bone weight, but urine Al excretion was still above normal. The repeat bone histomorphometric examination showed a good recovery of bone resorption which correlated well with serum parathyroid hormone levels, but poorer recovery of indices of bone formation and of the extent of Al deposits in the bone as shown by aluminon staining.

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