ESPEN practical short micronutrient guideline

BACKGROUND

Trace elements and vitamins, named together micronutrients (MNs), are essential for human metabolism. The importance of MNs in common pathologies is recognized by recent research, with deficiencies significantly impacting the outcome.

OBJECTIVE

This short version of the guideline aims to provide practical recommendations for clinical practice.

METHODS

An extensive search of the literature was conducted in the databases Medline, PubMed, Cochrane, Google Scholar, and CINAHL for the initial guideline. The search focused on physiological data, historical evidence (for papers published before PubMed release in 1996), and observational and/or randomized trials. For each MN, the main functions, optimal analytical methods, impact of inflammation, potential toxicity, and provision during enteral or parenteral nutrition were addressed. The SOP wording was applied for strength of recommendations.

RESULTS

The limited number of interventional trials prevented meta-analysis and led to a low level of evidence for most recommendations. The recommendations underwent a consensus process, which resulted in a percentage of agreement (%): strong consensus required of >90 % of votes. Altogether the guideline proposes 3 general recommendations and specific recommendations for the 26 MNs. Monitoring and management strategies are proposed.

CONCLUSION

This short version of the MN guideline should facilitate handling of the MNs in at-risk diseases, whilst offering practical advice on MN provision and monitoring during nutritional support.

Molecular Gatekeeper Discovery: Workflow for Linking Multiple Exposure Biomarkers to Metabolomics

The exposome reflects multiple exposures across the life-course that can affect health. Metabolomics can reveal the underlying molecular basis linking exposures to health conditions. Here, we explore the concept and general data analysis framework of "molecular gatekeepers"─key metabolites that link single or multiple exposure biomarkers with correlated clusters of endogenous metabolites─to inform health-relevant biological targets. We performed untargeted metabolomics on plasma from 152 adolescent girls participating in the Growing Up Healthy Study in New York City. We then performed network analysis to link metabolites to exposure biomarkers including five trace elements (Cd, Mn, Pb, Se, and Hg) and five perfluorinated chemicals (PFCs; n-PFOS, Sm-PFOS, n-PFOA, PFHxS, and PFNA). We found 144 molecular gatekeepers and annotated 22 of them. Lysophosphatidylcholine (16:0) and taurodeoxycholate were correlated with both n-PFOA and n-PFOS, suggesting a shared dysregulation from multiple xenobiotic exposures. Sphingomyelin (d18:2/14:0) was significantly associated with age at menarche; yet, no direct association was detected between any exposure biomarkers and age at menarche. Thus, molecular gatekeepers can also discover molecular linkages between exposure biomarkers and health outcomes that may otherwise be obscured by complex interactions in direct measurements.

Sources of unintentional manganese delivery in neonatal parenteral nutrition

BACKGROUND

Manganese (Mn) neurotoxicity is a concern in neonates receiving parenteral nutrition (PN). Prior studies have identified Mn contamination of PN ingredients as a source of daily Mn exposure from PN. This study was conducted to determine which neonatal PN ingredients are sources of this unintentional Mn delivery.

METHODS

Mn concentration was measured in different lot numbers of individual PN ingredients using inductively coupled plasma mass spectrometry (ICP-MS). PN admixtures were then prepared using standard doses of the tested individual ingredients and admixture Mn concentration was measured.

RESULTS

Magnesium sulfate and calcium gluconate are the major contributors to hidden unintentional Mn exposure in neonatal PN. Maximum measured Mn concentrations in these two ingredients were 443 and 46.8 mcg/L, respectively. Sodium and potassium phosphate were the next highest at 40 and 24 mcg/L, respectively. Other ingredients contained a trivial or no measurable quantity of Mn. PN admixture Mn content was 16-30% higher than predicted values based on individual ingredient Mn content. If infused at 150 mL/kg/day, a standard neonatal PN admixture with no added Mn is capable of unintentionally delivering up to 0.9 mcg/kg/day of Mn.

CONCLUSION

Neonatal PN without any added Mn provides close to the ASPEN recommended 1 mcg/kg/day dosage of Mn. This supports the potential utility of a Mn-omission approach to trace element provision in neonatal PN. Further studies are needed to test such an approach, and to evaluate the clinical significance of unintended Mn delivery in neonates receiving PN. This article is protected by copyright. All rights reserved.

Hypermanganesemia-Induced Cerebral Toxicity Mimicking an Acute Ischemic Stroke: A Case Report and Review of Overlapping Pathologies

Objective: To review and consider risk factors associated with the accumulation of and toxicity from manganese in patients receiving total parenteral nutrition (TPN). Case Summary: A 66-year-old female presented to the emergency department with right facial and arm weakness that initiated 1 hour prior to admission. Past medical history includes oral cancer with chronic aspiration and gastroparesis secondary to chemotherapy, TPN for 9 months, and a previous episode of right facial and arm parasthesias due to hypertensive emergency 4 years prior. The patient was assigned a National Institutes of Health Stroke Scale score of 6, cleared of an intracranial hemorrhage on imaging, and was administered tPA (tissue plasminogen activator) for an acute ischemic stroke after managing her hypertension to <185/110 mm Hg. Resolution of symptoms occurred within 24 hours. A magnetic resonance imaging of the patient's brain 24-hours post-tPA indicated an increased signal density in the globus pallidus, which in turn is linked with encephalopathy and has been described as a marker for hypermanganesemia. Discussion: Manganese is an essential trace element with a critical role in numerous physiologic functions. Though readily obtained from dietary sources and rarely causing issue, manganese provided to patients via TPN may result in toxicities. Though the presentation of neurotoxicities associated with TPN-delivered manganese has been previously documented, the clinical presentation of toxicity has never mimicked an acute ischemic stroke. Conclusion: Though an evaluation of overlapping pathologies is warranted, this patient's clinical presentation of manganese toxicity mimicked an acute ischemic stroke and resulted in the administration of a fibrinolytic. A more comprehensive appreciation of the implications of trace elements is demanded of clinicians.

Manganese Toxicity Associated With Total Parenteral Nutrition: A Review

Objective: To review hypermanganesemia-induced toxicities in adult patients receiving parenteral nutrition (PN) therapy. Data Sources: A comprehensive literature review was conducted from June 2020 to May 2021 on PubMED, MEDLINE, Scopus, ProQuest, the Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Web of Science. Study Selection and Data Extraction: Keyword and Boolean phrase searches were conducted using the following terminology: "manganese" OR "manganesemia" OR "manganism" or "hypermanganesemia" AND "total parenteral nutrition" OR "PN" or "parenteral nutrition" AND "toxicity" OR "accumulation." Appropriate filters, including "humans" and "English" and NOT "reviews," were utilized on all databases to improve search outcomes. Data Synthesis: A total of 4 reports detailing hypermanganesemia in 57 patient encounters were included in this review. Significant heterogeneity exists with regard to the duration of manganese supplementation and the dose of manganese. Toxicity associated with manganese was observed in as few as 15 days. The dose of manganese, though likely governed by content in commercially available products, may regularly exceed the recommendations of clinical guidelines and should be limited to 55 µg/day. Select patients with underlying malignancy, those with significant and prolonged Vitamin D deficiency, or those who have acquired a SLC30A10 genetic mutation may be at an increased risk of developing manganese toxicity. Conclusions: Clinicians must be cognizant of the concentration of trace elements added to PN, as manganese, and perhaps other biometals, may accumulate when dosed above the recommended daily allowances.

Evaluating the risk of manganese-induced neurotoxicity of parenteral nutrition: review of the current literature

INTRODUCTION

Several diseases and clinical conditions can affect enteral nutrition and adequate gastrointestinal uptake. In this respect, parenteral nutrition (PN) is necessary for the provision of deficient trace elements. However, some essential elements, such as manganese (Mn) may be toxic to children and adults when parenterally administered in excess, leading to toxic, especially neurotoxic effects.

AREAS COVERED

Here, we briefly provide an overview on Mn, addressing its sources of exposure, the role of Mn in the etiology of neurodegenerative diseases, and focusing on potential mechanisms associated with Mn-induced neurotoxicity. In addition, we discuss the potential consequences of overexposure to Mn inherent to PN.

EXPERT OPINION

In this critical review, we suggest that additional research is required to safely set Mn levels in PN, and that eliminating Mn as an additive should be considered by physicians and nutritionists on a case by case basis in the meantime to avoid the greater risk of neurotoxicity by its presence. There is a need to better define clinical biomarkers for Mn toxicity by PN, as well as identify new effective agents to treat Mn-neurotoxicity. Moreover, we highlight the importance of the development of new guidelines and practice safeguards to protect patients from excessive Mn exposure and neurotoxicity upon PN administration.

Nutritive Manganese and Zinc Overdosing in Aging C. elegans Result in a Metallothionein-Mediated Alteration in Metal Homeostasis

SCOPE

Manganese (Mn) and zinc (Zn) are not only essential trace elements, but also potential exogenous risk factors for various diseases. Since the disturbed homeostasis of single metals can result in detrimental health effects, concerns have emerged regarding the consequences of excessive exposures to multiple metals, either via nutritional supplementation or parenteral nutrition. This study focuses on Mn-Zn-interactions in the nematode Caenorhabditis elegans (C. elegans) model, taking into account aspects related to aging and age-dependent neurodegeneration.

METHODS AND RESULTS

Chronic co-exposure of C. elegans to Mn and Zn increases metal uptake, exceeding levels of single metal exposures. Supplementation with Mn and/or Zn also leads to an age-dependent increase in metal content, a decline in overall mRNA expression, and metal co-supplementation induced expression of target genes involved in Mn and Zn homeostasis, in particular metallothionein 1 (mtl-1). Studies in transgenic worms reveal that mtl-1 played a prominent role in mediating age- and diet-dependent alterations in metal homeostasis. Metal dyshomeostasis is further induced in parkin-deficient nematodes (Parkinson's disease (PD) model), but this did not accelerate the age-dependent dopaminergic neurodegeneration.

CONCLUSIONS

A nutritive overdose of Mn and Zn can alter interactions between essential metals in an aging organism, and metallothionein 1 acts as a potential protective modulator in regulating homeostasis.

Manganese in the Diet: Bioaccessibility, Adequate Intake, and Neurotoxicological Effects

Manganese (Mn) is an essential element that participates in several biological processes. Mn serves as a cofactor for several enzymes, such as glutamine synthetase and oxidoreductases, that have an important role in the defense of the organisms against oxidative stress. The diet is the main source of Mn intake for humans, and adequate daily intake levels for this metal change with age. Moreover, in higher amounts, Mn may be toxic, mainly to the brain. Here, we provide an overview of Mn occurrence in food, addressing its bioaccessibility and discussing the dietary standard and recommended intake of Mn consumption. In addition, we review some mechanisms underlying Mn-induced neurotoxicity.

Manganese-induced neurodegenerative diseases and possible therapeutic approaches

INTRODUCTION

Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and prion disease represent important public health concerns. Exposure to high levels of  heavy metals such as manganese (Mn) may contribute to their development.

AREAS COVERED

In this critical review, we address the role of Mn in the etiology of neurodegenerative diseases and discuss emerging treatments of Mn overload, such as chelation therapy. In addition, we discuss natural and synthetic compounds under development as prospective therapeutics. Moreover, bioinformatic approaches to identify new potential targets and therapeutic substances to reverse the neurodegenerative diseases are discussed.

EXPERT OPINION

Here, the authors highlight the importance of better understanding the molecular mechanisms of toxicity associated with neurodegenerative diseases, and the role of Mn in these diseases. Additional emphasis should be directed to the discovery of new agents to treat Mn-induced diseases, since present day chelator therapies have limited bioavailability. Furthermore, the authors encourage the scientific community to develop research using libraries of compounds to screen those compounds that show efficacy in regulating brain Mn levels. In addition, bioinformatics may provide novel insight for pathways and clinical treatments associated with Mn-induced neurodegeneration, leading to a new direction in Mn toxicological research.

Manganese Enhanced MRI for Use in Studying Neurodegenerative Diseases

MRI has been extensively used in neurodegenerative disorders, such as Alzheimer’s disease (AD), frontal-temporal dementia (FTD), mild cognitive impairment (MCI), Parkinson’s disease (PD), Huntington’s disease (HD) and amyotrophic lateral sclerosis (ALS). MRI is important for monitoring the neurodegenerative components in other diseases such as epilepsy, stroke and multiple sclerosis (MS). Manganese enhanced MRI (MEMRI) has been used in many preclinical studies to image anatomy and cytoarchitecture, to obtain functional information in areas of the brain and to study neuronal connections. This is due to Mn²⁺ ability to enter excitable cells through voltage gated calcium channels and be actively transported in an anterograde manner along axons and across synapses. The broad range of information obtained from MEMRI has led to the use of Mn²⁺ in many animal models of neurodegeneration which has supplied important insight into brain degeneration in preclinical studies. Here we provide a brief review of MEMRI use in neurodegenerative diseases and in diseases with neurodegenerative components in animal studies and discuss the potential translation of MEMRI to clinical use in the future.