Bone Mineral Composition Among Long-Term Parenteral Nutrition Patients: Postmortem Assessment of Calcium, Phosphorus, Magnesium, and Select Trace Elements.

BACKGROUND: Patients receiving long-term parenteral nutrition (PN) treatment are at risk of developing metabolic bone diseases (MBDs). The bone compartment serves as a repository for a range of metal(loid)s that are administered intravenously to patients via PN solutions. Thus, the mineral composition of patient bones may be linked to the development of MBDs in this group. METHODS: We measured 12 elements in bone samples obtained post mortem from 7 long-term (2-21 years) PN patients and 18 control bones obtained from hip/knee replacement surgery. The samples were cleaned, digested, and subsequently analyzed using a method based on inductively coupled plasma tandem mass spectrometry. RESULTS: Compared with the control group, bones obtained from PN patients were significantly (P < 0.05) depleted in calcium (Ca), phosphorus (P), magnesium (Mg), chromium, and strontium and enriched in manganese (Mn), zinc, barium, cadmium (Cd), and uranium (U). No differences were observed for cobalt or lead. CONCLUSIONS: Depletion of major components of bone mineral (Ca, P, and Mg) and enrichment in known toxicants (Cd, Mn, U) are concerns for PN patients.

An assessment of exposure to rare earth elements among patients receiving long-term parenteral nutrition.

Patients receiving long-term parenteral nutrition (PN) are exposed to potentially toxic elements, which may accumulate in bone. Bone samples collected from seven PN patients (average = 14 years) and eighteen hip/knee samples were analyzed for Al as part of a previous investigation. Yttrium was serendipitously detected in the PN bone samples, leading to the present investigation of rare earth elements (REEs). A method for quantitating fifteen REEs in digested bone was developed based on tandem ICP-MS (ICP-MS/MS) to resolve spectral interferences. The method was validated against nine biological reference materials (RMs) for which assigned values were available for most REEs. Values found in two NIST bone SRMs (1400 Bone Ash and 1486 Bone Meal) compared favorably to those reported elsewhere. Method detection limits ranged from 0.9 ng g-1 (Tm) to 5.8 ng g-1 (Y). Median REE values in the PN patient group were at least fifteen times higher than the "control" group, and exceeded all previously reported data for eleven REEs in human bones. REE content in PN bones normalized to the Earth's upper crust revealed anomalies for Gd in two patients, likely from exposure to Gd-containing contrast agents used in MRI studies. A retrospective review of the medical record for one patient revealed an almost certain case of nephrogenic systemic fibrosis, associated with Gd exposure. Analysis of two current PN formulations showed traces of REEs with relative abundances similar to those found in the PN bones, providing convincing evidence that PN solutions were the primary source of REEs in this population.

Excessive aluminum accumulation in the bones of patients on long-term parenteral nutrition: postmortem analysis by electrothermal atomic absorption spectrometry.

BACKGROUND: Aluminum (Al) contamination of parenteral nutrition (PN) solutions remains a concern for long-term PN patients. Al accumulates particularly in bone. Excessive exposure to Al may result in increased Al body burden and impaired bone formation and mineralization, leading to bone disease. Although the U.S. Food and Drug Administration (FDA) has limited Al contamination in large-volume parenteral solutions, small-volume parenterals may still contribute considerable amounts of Al to PN solutions. The goal of this study is to determine whether or not long-term adult PN patients remain at risk for increased bone Al accumulation. METHODS: We measured Al accumulation in autopsy bones from 7 patients who had received PN for 2-21 years and compared bone Al levels with those in living control patients undergoing hip or knee replacement. Electrothermal atomic absorption spectrometry was used for bone Al measurements. RESULTS: When compared with bone Al content in controls, markedly elevated Al levels (P < .0001) were found in the bones of all but 1 patient, who received PN for only 2 years before death. Even greater Al accumulation was found for PN patients who developed late renal impairment (P = .0159). CONCLUSIONS: We conclude that long-term adult PN patients continue to be at risk for Al toxicity.

Micronutrients in parenteral nutrition: too little or too much? The past, present, and recommendations for the future.

This research workshop in 2009 grew out of a concern in the United States, Europe, and other countries with advanced medicine that it was time to revisit the parenteral requirements for a number of micronutrients. Critical questions sought to be answered included the following: Were there micronutrients not routinely added that should be part of a parenteral nutrition (PN) formula? Were other micronutrients present but in inappropriate amounts? How are various micronutrient requirements altered in the critically or chronically ill?

The Neurologic Syndrome of Vitamin E Deficiency: Laboratory and Electrophysiologic Assessment.

A human requirement for vitamin E was established in the 1960s; however, its role in neurologic function has been recognized only for the past 10 years. The neurologic syndrome of vitamin E deficiency is seen in patients with chronic steatorrhea and principally affects functions of the spinal cord posterior column and retina; however, it can also involve other parts of both the central and peripheral nervous system and the proximal muscles. This review examines the clinical and laboratory assessment of patients suspected of having vitamin E deficiency and points out the importance of recognizing the syndrome since many of the incapacitating symptoms are largely reversible.