Aluminum exposure through parenteral nutrition formulations: Mathematical versus clinical relevance

Unexpected Serum and Urine Aluminum Concentrations in Pediatric Patients on Home Parenteral Nutrition

The intravenous supply of aluminum (Al) present in parenteral nutrition solutions poses a high risk of the absorption of this element, which can result in metabolic bone disease, anemia, and neurological complications. The aim of this study is to determine the impact of long-term parenteral nutrition (PN) in children on serum Al concentration and its urinary excretion compared to healthy children. We evaluated serum Al concentrations and its urinary excretion in patients enrolled in the Polish home parenteral nutrition (HPN) program between 2004 and 2022. The study group included 83 patients and the control group consisted of 121 healthy children. In children whose PN was started in the neonatal period, we found higher serum Al concentrations and higher urinary Al excretion than in other subjects whose PN was started later. Only 12% of the children on chronic parenteral nutrition had serum Al concentrations of less than 5 μg/L. Healthy children in the control group had higher serum Al concentrations than those in the parenteral nutrition group, which may indicate the influence of one's environment and diet on Al serum levels.

Aluminum Exposure from Parenteral Nutrition: Early Bile Canaliculus Changes of the Hepatocyte

Background: Neonates on long-term parenteral nutrition (PN) may develop parenteral nutrition-associated liver disease (PNALD). Aluminum (Al) is a known contaminant of infant PN, and we hypothesize that it substantially contributes to PNALD. In this study, we aim to assess the impact of Al on hepatocytes in a piglet model. Methods: We conducted a randomized control trial using a Yucatan piglet PN model. Piglets, aged 3–6 days, were placed into two groups. The high Al group (n = 8) received PN with 63 µg/kg/day of Al, while the low Al group (n = 7) received PN with 24 µg/kg/day of Al. Serum samples for total bile acids (TBA) were collected over two weeks, and liver tissue was obtained at the end of the experiment. Bile canaliculus morphometry were studied by transmission electron microscopy (TEM) and ImageJ software analysis. Results: The canalicular space was smaller and the microvilli were shorter in the high Al group than in the low Al group. There was no difference in the TBA between the groups. Conclusions: Al causes structural changes in the hepatocytes despite unaltered serum bile acids. High Al in PN is associated with short microvilli, which could decrease the functional excretion area of the hepatocytes and impair bile flow.

Intestinal Failure-Associated Metabolic Bone Diseases and Response to Teriparatide

Patients requiring home parenteral nutrition (PN) may develop metabolic bone disease, the etiology of which can be multifactorial. We report a case of significantly low bone mass in a postmenopausal woman with history of short bowel syndrome, renal impairment, and previous radiation exposure who responded to intermittent subcutaneous administration of parathyroid hormone. Her bone mineral density normalized after she completed a course of 18 months of treatment, and a bone isotope scan was negative for skeletal malignancy.

Aluminum Toxicity in Neonatal Parenteral Nutrition: What Can We Do?

Aluminum toxicity has been described in patients of all ages who are receiving a variety of therapies, including dialysis, phosphate-binding medications, and parenteral nutrition (PN). Neonates are at an increased risk of aluminum toxicity because of anatomic, physiologic, and nutrition-related factors not present in other populations. In 2004, the Food and Drug Administration recommended restricting daily aluminum administration to 5 μg/kg/day and now requires that additives used to compound PN have the maximum aluminum content at expiration listed on the product label. Although the pharmacist can work to decrease aluminum toxicity in this population, it remains difficult to reach this threshold.

Potential Aluminum Exposure from Parenteral Nutrition in Patients with Acute Kidney Injury

Background:

Patients' exposure to and potential toxicity from aluminum in parenteral nutrition (PN) formulations is an important concern of healthcare providers.

Objective:

To determine the potential for aluminum toxicity caused by PN in hospitalized adults who have risk factors of both acute kidney injury and PN.

Methods:

Adults who required PN and had a serum creatinine (SCr) level at least 1.5 times greater than the admission SCr on the first day of PN were studied in a retrospective fashion. Protein was administered based on whether hemodialysis was being used (0 6-1 g/kg/day without hemodialysis; 1.2-1.5 g/kg/day with hemodialysis). Aluminum exposure was determined for each patient by multiplying the volume of each PN component by its concentration of aluminum Unpaired f-tests, Fisher's exact test, and analysis of variance were used for statistical analysis. Data are presented as mean ± SD.

Results:

Thirty-six patients (aged 50.4 ± 20.4 y; weight 90.2 ± 32.8 kg) were studied. Initial serum urea nitrogen and SCr were 47 ± 23 and 3.3 ± 1.4 mg/dL. respectively. Twelve patients received hemodialysis. The mean aluminum exposure was 3.8 ± 2 μg/kg/day in the 36 patients, Of these, 29 had safe calculated aluminum exposure (<5 μg/kg/day) and 7 had high calculated aluminum exposure (>5 μg/kg/day), Patients with safe aluminum exposure had significantly higher SCr levels than did those with high aluminum exposure (3.5 ± 1.5 vs 2.2 ± 0.7 mg/dL; p < 0.04). Patients with high aluminum exposure received significantly more aluminum from calcium gluconate compared with those who had safe aluminum exposure (357 ± 182 vs 250 ± 56 μg/day; p < 0.02). Limitations of the study include its retrospective design, which resulted in calculated versus direct measurement of aluminum.

Conclusions:

Using our calculations, we believe that most patients with acute kidney injury who require PN do not receive excessive exposure to aluminum from the PN formulation, despite having 2 risk factors (acute kidney injury, PN) for aluminum toxicity,

Effect of additive selection on calculated aluminum content of parenteral nutrient solutions

PURPOSE

The quantity of aluminum in common ingredients used to compound parenteral nutrient (PN) solutions was calculated to quantify the actual aluminum content, and opportunities to modify the aluminum content by changing the manufacturer of the ingredients were explored.

METHODS

A retrospective evaluation of a random sample of 10 neonatal, 10 pediatric, and 10 adult patients who received PN solutions was performed to quantify the aluminum content in these solutions on the basis of the ingredients used at the authors' institution. A recalculation was performed using the lowest aluminumcontaining ingredients to determine the potential for aluminum minimization in each PN solution.

RESULTS

Various manufacturers produce each ingredient required to make PN solutions. Significant variation exists among manufacturers, vial size, and concentrations. Statistically significant differences in the mean aluminum content of PN solutions before and after aluminum minimization were found to exist within each sample of patients. Among the neonatal PN solutions, aluminum content was significantly reduced from a mean +/- S.D. of 84.16 +/- 47.61 to 33.6 +/- 16.69 mug/kg/day. The pediatric PN solutions had a significant decline in aluminum content from a mean +/- S.D. of 16.24 +/- 3.66 to 6.84 +/- 2.66 mug/kg/day. Aluminum content in the high-risk adult PN solutions significantly decreased from a mean +/- S.D. of 4.58 +/- 2.06 to 2.31 +/- 0.63 mug/kg/day.

CONCLUSION

There is wide variability in the aluminum concentration of injectable products used in the compounding of PN solutions. Selecting products with low aluminum concentration may substantially reduce the amount of the element administered to patients.

Ion-exchange and potentiometric characterization of Al–cystine and Al–cysteine complexes

The interaction between aluminium and cysteine and cystine was evaluated by means of ion-exchange experiments and potentiometry. Ion-exchange experiments included other ligands with affinity for aluminium and two kinds of resins, either a Na+ -form or an Al3+ -form exchanger. The ability of the ligands to keep aluminium in solution in the presence of the Na+ exchanger or to withdraw it from the Al3+ -form resin was evaluated. Aluminium quantification was carried out by either graphite-furnace or flame atomic absorption spectrometry. Aluminium extraction isotherms were linearised using the Scatchard plot, and stability constants were obtained from the curves' slopes. The experiments showed that the ability of the ligands to withdraw aluminium from the Al3+ -form resin increased following the order cysteine < oxalate < citrate = cystine < nitrilotriacetic acid < ethylenediaminetetraacetic acid. Potentiometric titrations, carried out in aqueous solution with constant ionic strength and temperature, showed that the predominant species in solution have a metal-ligand proportion of 1:1 for both amino acids. The main species are Al(OH)3L, with log K of 6.2 for cysteine, and AlL and Al(OH)L, with log K of 10.3 and 1.7, respectively, for cystine. Stability constants obtained from the Scatchard plots showed a linear correlation with the stability constants obtained by potentiometry for cystine and cysteine in this work and those collected from the literature for the other ligands. These results show that cysteine and cystine extract and maintain aluminium in solution, which may explain elevated concentrations of aluminium in parenteral nutrition solutions containing these amino acids.

Recent developments in aluminium contamination of products used in parenteral nutrition

PURPOSE OF REVIEW

This review evaluates recent developments concerning aluminium contamination of products used in the preparation of parenteral nutrition solutions and the failure of the pharmaceutical industry to respond to these concerns. The difficulty in meeting the intent of the recent US Food and Drug Administration mandate to reduce aluminium exposure with currently available parenteral nutrition additives is addressed. This review also summarizes the issues associated with aluminium toxicity, the patient populations at risk, treatment options, and compounding considerations.

RECENT FINDINGS

Unfortunately, the published literature detailing the toxicities seen from aluminium exposure in the parenteral nutrition patient are primarily limited to those published in the 1980s and 1990s. Recent publications refer back to these classic papers and discuss the challenges that practitioners face when trying to apply the recommendations of the recently implemented Food and Drug Administration mandate with outdated literature. Few studies have been published to validate those earlier findings.

SUMMARY

The issues surrounding aluminium toxicity are real and must be addressed. In order to make meaningful changes in clinical practice, low aluminium parenteral nutrition additives are needed and studies must be conducted using currently available products. It remains a challenge to optimize nutritional intake from parenteral nutrition and at the same time reduce aluminium exposure.