Aluminium Accumulates on Inactive Bone Surfaces After Parathyroidectomy in Uremic Rats

In recent studies on bone biopsies of long-term hemodialyzed patients, parathyroidectomy (PTx) has been shown to represent a risk factor for subsequent accumulation of aluminium (Al) in the bone. Therefore, the influence of late PTx on Al metabolism in uremic rats previously given 11 mg Al intraperitoneally during a period of four weeks was studied. Al content was determined in the blood, liver, bone and feces 7 and 14 days after PTx. During PTx, each animal also received 2 intramuscular implants of partially demineralized bone matrix cylinders, which served as inactive bone surfaces. In PTx animals, the Al content in the liver, spleen and kidney progressively decreased, while its blood levels increased in spite of the fact that the treatment was stopped. Bone values remained unchanged but Al markedly accumulated on inactive mineralized surfaces of implanted cylinders. Significant amounts of Al in fecal masses could indicate its biliary excretion. The results were influenced neither by changes in 1,25-(OH)2D3 or serum calcium values, nor by different degrees of renal failure after PTx. It is suggested that accumulation of Al in the bone after PTx, as found in dialyzed patients, constitutes a passive event triggered by inactive bone tissue.