Aluminum loading during total parenteral nutrition

Toxicity of gestational aluminum exposure to the maternal rabbit and offspring

To assess aluminum toxicity to the Al-exposed pregnant female and her developing offspring, pregnant rabbits received 20 sc Al lactate injections (0, 25, 100, or 400 mumol Al/kg/inj) between Days 2 and 27 of gestation. Fifty-eight percent perinatal mortality resulted from the highest dose. At 2 days postpartum litters were culled to six offspring. Three of the offspring of Al-treated does were cross-fostered to a non-Al-treated doe in exchange for three of the non-Al-treated doe's offspring. Tissue Al concentrations in 0- to 2-day-old offspring positively correlated with their does' Al exposure, but were lower than Al concentrations in placental tissue or in does 5 weeks postpartum, suggesting that the placenta partially protects the fetus from Al. Offspring of 25 mumol group does gained body weight faster than controls, whereas 400 mumol group does and their offspring gained weight less rapidly than controls. The weight of milk consumed by offspring inversely correlated with their does' Al exposure. Learning a classically conditioned reflex was facilitated by lower and impaired by higher Al exposure in offspring conditioned at 7 and 11 weeks of age. Offspring receiving higher Al exposure also showed impaired memory of the learned reflex. Aluminum appears to distribute into the developing fetus where it accumulates and can produce delayed effects which may be beneficial following lower but detrimental following higher exposure concentrations.

Determination of desferoxamine and a major metabolite by high-performance liquid chromatography. Application to the treatment of aluminium-related disorders

A high-performance liquid chromatography method is described that permits separation and quantification of desferoxamine, a major metabolite, the iron(III) and the aluminum(III) chelates of desferoxamine. This method now facilitates pharmacokinetic studies on desferoxamine and derivatives designed to study side-effects and metabolite patterns in patients undergoing treatment.

Evidence of aluminum loading in infants receiving intravenous therapy

To investigate the possibility that premature infants may be vulnerable to aluminum toxicity acquired through intravenous feeding, we prospectively studied plasma and urinary aluminum concentrations in 18 premature infants receiving intravenous therapy and in 8 term infants receiving no intravenous therapy. We also measured bone aluminum concentrations in autopsy specimens from 23 infants, including 6 who had received at least three weeks of intravenous therapy. Premature infants who received intravenous therapy had high plasma and urinary aluminum concentrations, as compared with normal controls: plasma aluminum, 36.78 +/- 45.30 vs. 5.17 +/- 3.1 micrograms per liter (mean +/- S.D., P less than 0.0001); urinary aluminum:creatinine ratio, 5.4 +/- 4.6 vs. 0.64 +/- 0.75 (P less than 0.01). The bone aluminum concentration was 10 times higher in infants who had received at least three weeks of intravenous therapy than in those who had received limited intravenous therapy: 20.16 +/- 13.4 vs. 1.98 +/- 1.44 mg per kilogram of dry weight (P less than 0.0001). Creatinine clearances corrected for weight did not reach expected adult values until 34 weeks of gestation. Many commonly used intravenous solutions are found to be highly contaminated with aluminum. We conclude that infants receiving intravenous therapy have aluminum loading, which is reflected in increased urinary excretion and elevated concentrations in plasma and bone. Such infants may be at high risk for aluminum intoxication secondary to increased parenteral exposure and poor renal clearance.

Aluminum intake from non-prescription drugs and sucralfate

The use of non-prescription antacids to control hyperphosphatemia has been implicated as a primary cause of aluminum intoxications in patients with reduced renal function. Additional reports suggest that oral aluminum intake may have adverse effects on mineral metabolism of patients with normal renal function. The non-prescription drugs that contain substantial quantities of aluminum salts include some antacids, buffered aspirins, antidiarrheals, and vaginal douches. Sucralfate, an anti-ulcer drug available by prescription, is the aluminum salt of sucrose sulfate. If taken as directed, the daily aluminum intake from the antacids can be as much as 5,000 mg. When aluminum buffered aspirins are used as part of the drug therapy for rheumatoid arthritis, aluminum intake can be elevated by 700 mg/day. Although aluminum intoxications have been reported among patients with reduced renal function, existing reports are not sufficient to estimate whether the chronic elevation of aluminum intake from drugs is causing adverse health effects among other patient populations.

Trace elements in human body fluids and tissues

Published figures for trace element concentrations in body fluids and tissues of apparently healthy subjects are widely divergent. For a considerable time, the apparent disparities were readily ascribed to biological sources of variation such as age, sex, dietary habits, physiological conditions, environmental exposure, geographical circumstances, or similar influences. Growing evidence, however, suggests that this interpretation may be seriously questioned in numerous instances. First, values obtained in reference materials leave no doubt that some previous studies must have been subject to gross analytical inaccuracies. Second, it has now been thoroughly documented that inadequate sample collection and manipulation may drastically distort the intrinsic trace element content of biological matrices. This review scrutinizes data reported by a number of investigators. In an effort to settle the currently flourishing confusion, critically selected reference values are set forth for trace element levels in human blood plasma or serum, packed blood cells, urine, lung, liver, kidney, and skeletal muscle tissue.

Parenteral aluminum administration in the dog: II. Induction of osteomalacia and effect on vitamin D metabolism

There is an association between bone aluminum (Al) accumulation and dialysis-associated osteomalacia (OM). To study whether Al is pathogenic in OM, quantitative bone histomorphometry was done in six dogs before (Bx 1) and after (Bx 2) 3 to 5 weeks of intravenous Al administration (1 mg Al /kg/day). Bone Al was determined by histochemical and chemical methods. The percent osteoid rose from 2.8 +/- 0.8 to 7.0 +/- 4.3% (mean +/- SD), P less than 0.05, and osteoid width increased from 5.7 +/- 0.6 to 8.0 +/- 1.2 mu, P less than 0.01, after Al. Bone Al rose from 1.3 +/- 1.6 to 94.0 +/- 19.0 mg/kg after Al, and the severity of OM, expressed as either percent forming surface or percent osteoid, correlated with bone Al measured histochemically and expressed as either percent surface or percent area of trabecular bone staining for Al (r = 0.85 - 0.90, P less than 0.01). Poor tetracycline uptake (six dogs), which indicates impaired mineralization, and little or no separation of tetracycline labels (four dogs) were noted at Bx 2; thus, bone apposition and formation rates were below the limits of detection. Resorptive surface did not change but trabecular volume, expressed as percent of tissue volume, fell from 22.1 +/- 3.0 to 17.1 +/- 1.4%, P less than 0.05. Serum levels of 1,25(OH)2D fell from 26.8 +/- 9.1 to 4.5 +/- 5.5 pg/ml after 17 days of Al; serum 25(OH)D levels were unchanged. These data indicate that Al can cause OM and that its severity correlates with the bone Al content.2 +

Parenteral aluminum administration in the dog: I. Plasma kinetics, tissue levels, calcium metabolism, and parathyroid hormone

Aluminum (Al) may cause both osteomalacia and encephalopathy in dialysis patients. Little is known about the biology of Al. This study examined the initial distribution kinetics of Al and its biological effects after injections of 1 mg/kg/day into dogs for 3 to 5 weeks. Following one intravenous dose, the plasma half-life (x +/- SE) was 276 +/- 51.8 min, with an apparent volume of distribution of 1.30 +/- 0.17 liters or 5.90 +/- 0.30% body wt; 10 to 21% of administered Al was excreted in the urine over 150 min, and the renal contribution to plasma clearance of Al correlated with GFR (r = 0.77, P less than 0.05). The total plasma clearance of Al (4.43 +/- 2.83 ml/min) exceeded the renal contribution to plasma clearance (1.94 +/- 0.36 ml/min) in each dog, and in only two instances did the renal contribution reach 50% of total plasma clearance. Serum calcium rose from 9.4 +/- 0.2 to 11.1 +/- 0.3 mg/dl and immunoreactive parathyroid hormone (iPTH) fell by 27 +/- 4% following one Al injection. With repeated Al injections, serum calcium increased from baseline levels of 10.2 +/- 0.07 mg/dl to 11.1 +/- 0.22 and 11.3 +/- 0.46 mg/dl after 1 and 2 weeks, respectively. Renal function declined in all dogs, and serum creatinine exceeded 3.5 mg/dl in four; over the 5 weeks of study, serum calcium correlated with serum creatinine (r = 0.91, P less than 0.001). Liver, kidney, and spleen showed the highest tissue content of Al, and there was substantial uptake by bone; the parathyroid content of Al was modest.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic bone disease associated with total parenteral nutrition

Patients receiving long-term treatment with total parenteral nutrition often develop bony abnormalities characterized by patchy osteomalacia and low bone turnover. The patients present evidence of physiologic hypoparathyroidism, although low levels of iPTH cannot entirely explain the osteomalacia. Abnormally low serum levels of 1,25(OH)2-vitamin D have been demonstrated, but the significance of these reduced levels in the pathogenesis of the bone lesions is not defined. Aluminum has been detected in large quantities in the plasma, urine, and bone of some patients treated with TPN, and there is mounting evidence that aluminum may be associated with skeletal pathology, particularly osteomalacia. There is, however, no clear documentation that aluminum accumulation produces the skeletal lesions observed, although it could be a contributing factor. There has been the unusual empiric observation that the removal of vitamin D2 from the infusate is associated with a decrease in the quantity of unmineralized osteoid in TPN patients. A possible role of vitamin D2 in producing osteomalacia is not easy to understand since normal serum levels of 25(OH)-D2, the circulating form of vitamin D2, have been reported. The long-term consequences of intravenous nutritional support for many aspects of metabolism remain unknown. Administration into the systemic circulation of predetermined quantities of calcium and phosphorus via a route that bypasses their passage across the intestinal mucosa, the portal system and the liver may have adverse consequences. It is possible that bypassing homeostatic mechanisms may affect bone formation and metabolism or lead to alterations in vitamin D sterols. Alternatively, a deficiency of an essential trace metal or the accumulation of a toxic trace substance could be responsible for the bony abnormalities. Much remains to be clarified concerning calcium homeostasis and bone disease during total parenteral nutrition. Among various possible factors, it seems likely that the significance of the low levels of 1,25(OH)2-vitamin D and of the accumulation of aluminum in this condition will soon be clarified.

The health effects of aluminum compounds in mammals

This review, which is based on evaluation of information published in the last decade related to the health effects of aluminum compounds in mammals, directs attention to the well-documented effects of A1(III) compounds on phosphate metabolism. It is suggested that the toxic effects currently associated with A1(III) compounds are dependent upon the nature of A1(III) complexes formed from electron donating groups, rather than restricted to the presence of the high charge density matrix of A1(III) itself.

Persistent aluminum accumulation after prolonged systemic aluminum exposure

To determine the distribution of aluminum (A1) following systemic exposure, female New Zealand white rabbits were given 20 subcutaneous injections, over 4 weeks, of 0, 25, 50, 100, 200, or 400 μmol A1/kg/injection, as the lactate salt. They were sacrificed 5 weeks after completion of injections and selected tissues removed for graphite furnace atomic absorption analysis of tissue A1 content. Rabbits not receiving A1 injections had mean tissue A1 concentrations ranging from 1.5-7.4 μg/g. Bone was higher, 18.7 μg/g. All tissues, except for muscle, demonstrated an increase in A1 concentration correlating with the A1 exposure. After 400 μmol A1/kg/injection for 20 injections, tissue A1 concentrations were: bone 90, heart 12, kidney-cortex 1290, kidney-medulla 245, liver 246, lung 19, and spleen 465 μg A1/g. The average of the 5 central nervous system regions sampled (frontal grey, white, hippocampus, cerebellum, and spinal cord) rose 53% over controls. Determination of A1 in kidney, liver, or bone may be useful in diagnosis of A1 overload conditions in humans (dialysis encepthalopathy, dialysis osteomalacia, and parenteral nutrition-associated osteomalacia). The rabbit appears to be a useful model to further study A1 intoxication syndromes.

Excretion and retention of low or moderate levels of aluminium by human subjects

During a 40-day balance study, eight adult males were fed two levels of aluminium: 5 mg/day for 20 days (control diet) and 125 mg/day for 20 days (test diet). Every subject excreted more than 96% and more than 74% of his aluminium intake in his faeces when fed the test and control diets, respectively. Subjects excreted two- to five-fold more aluminium in their urine and had significantly higher levels of aluminium in their sera when fed the test diet rather than the control diet. No retention of aluminum was detected when faecal and urinary losses of aluminium were compared with intakes.