Metabolism and possible health effects of aluminum.

Abstract

Literature regarding the biochemistry of aluminum and eight similar ions is reviewed. Close and hitherto unknown similarities were found. A hypothetical model is presented for the metabolism, based on documented direct observations of Al3+ and analogies from other ions. Main characteristics are low intestinal absorption, rapid urinary excretion, and slow tissue uptake, mostly in skeleton and reticuloendothelial cells. Intracellular Al3+ is probably first confined in the lysosomes but then slowly accumulates in the cell nucleus and chromatin. Large, long-lived cells, e.g., neurons, may be the most liable to this accumulation. In heterochromatin, Al3+ levels can be found comparable to those used in leather tannage. It is proposed that an accumulation may take place at a subcellular level without any significant increase in the corresponding tissue concentration. The possible effects of this accumulation are discussed. As Al3+ is neurotoxic, the brain metabolism is most interesting. The normal and the lethally toxic brain levels of Al3+ are well documented and differ only by a factor of 3-10. The normal brain uptake of Al3+ is estimated from data on intestinal uptake of Al3+ and brain uptake of radionuclides of similar ions administered intravenously. The uptake is very slow, 1 mg in 36 years, and is consistent with an assumption that Al3+ taken up by the brain cannot be eliminated and is therefore accumulated. The possibility that Al3+ may cause or contribute to some specific diseases, most of them related to aging, is discussed with the proposed metabolic picture in mind.

Effect of High Aluminum Concentration in Water Resources on Human Health, Case Study: Biga Peninsula, Northwest Part of Turkey

“…The amount of Al directly passing into the blood from the digestive system is \1% (Flaten 2001). Al is found in small amounts in the serum, after being taken via the digestive system in normal ways (1-2 lg/l) (Flaten 2001;Ganrot 1986;Krewski et al 2007). A large amount of Al is stored in various tissues such as bones and lungs.…”

“…A large amount of Al is stored in various tissues such as bones and lungs. In healthy people, Al is normally discharged from the body through the kidneys (Flaten 2001;Ganrot 1986;Krewski et al 2007). The serum Al level might increase up to 30 lg/l in the dialysis patients having chronic renal deficiency.…”

“…The serum Al level might increase up to 30 lg/l in the dialysis patients having chronic renal deficiency. In dialysis patients with chronic renal deficiency, high Al levels may result in problems such as osteomalacia and dialysis encephalopathy or dementia (Flaten 2001;Ganrot 1986;Krewski et al 2007).…”

Health risk implications from simultaneous exposure to multiple environmental contaminants

“…Premature infants have been found to be the most sensitive to Al exposure (Hellström et al, 2008;Driscoll et al, 1997). Aluminium is exponentially accumulated in the body with ageing and can trigger excess apoptosis (cell death) (Ganrot, 1986) which impairs certain cellular immune responses (Prolo et al, 2007). These impacts are of special concern in South Africa, where the elderly and HIV infected persons already suffer from compromised immune systems making them even more vulnerable to other serious infections (Hellström et al, 2008).…”

Aluminium intoxication in a dog

“…Methodological problems such as sample handling (6), determinations in tissue components (5) and the lack of a useful radio-isotope seriously limit knowledge concerning the various aspects of the metal. Spontaneous intoxication in dogs has not been reported.…”