Lanthanum-induced neurotoxicity: solving the riddle of its involvement in cognitive impairment?

Association between prenatal exposure to rare earth elements and the neurodevelopment of children at 24-months of age: A prospective cohort study

The increasing consumption of rare earth elements (REEs) has resulted in a considerable risk of environmental exposure. However, the adverse effects of prenatal REEs exposure on children's neurodevelopment are not yet fully recognized. Therefore, we investigated the individual and joint effects of prenatal exposure to 13 REEs on children's neurocognitive development based on 809 mother-child pairs from a large birth cohort in Wuhan, China. Maternal urinary concentrations of 13 REEs were repeatedly measured by inductively coupled plasma mass spectrometry. Children's neurodevelopment [e.g., mental and psychomotor development index (MDI/PDI)] at 24-months was assessed using Bayley Scales of Infant Development of Chinese Revision. GEE and BKMR models were applied to estimate the individual and joint effects of prenatal REE exposure on child neurodevelopment level. After controlling for typical confounders, we observed that exposure to 9 REEs during the first trimester were significantly associated with decreased MDI scores [βs and 95% confidence intervals (CIs) ranging from -2.24 (-3.86 ∼ -0.63) to -1.44 (-2.26∼ -0.26)], and 7 REEs during third trimester were significantly associated decreased PDI scores [β and 95% CIs ranging from -1.95 (-3.19 ∼ -0.71) to -1.25 (-2.34 ∼ -0.16)]. Higher quantiles of REE mixture in first and third trimester were associated with decreased MDI and PDI score. Thulium, erbium in the first trimester and cerium, lanthanum in the third trimester accounted most importance to joint effects on MDI and PDI, respectively. In conclusion, prenatal exposure to higher concentrations of REEs during the first and third trimester were negative associated with children's neurodevelopment.

Short-Term Toxicity of Lanthanum to Embryonic and Yolk-Sac Stage Larvae of the Rare Minnow Gobiocypris rarus Ye & Fu, 1983

The wide use of rare-earth elements in China for aquacultural purposes and many other applications has resulted in their accumulation in the aquatic environment and has caused concern about their safety. In this study, we tested the toxicity of lanthanum (La (III)) to the early life stages (embryonic and sac-fry stages) of the rare minnow Gobiocypris rarus Ye & Fu, 1983. We exposed fertilized eggs to 0, 0.06, 0.13, 0.25, 0.50, 1.00, and 1.92 mg/L of La (III) until the yolk sac was exhausted in any group (at about 168 h of exposure). Exposure to 1.00 and 1.92 mg/L La (III) had obvious lethal effects on embryos, La (III) exposure also accelerated the development of embryos and had a significant inhibitory effect on the hatching rate after 96 h. As the exposure time increased, the larvae exhibited obvious yolk-sac edema, pericardium edema, spinal curvature, tail bending, and other symptoms of poisoning, including deflated swim-bladder. In general, these results clearly indicate that La pollutants hinder the development of rare minnow embryos and are acutely toxic to rare minnow larvae. Our finding would provide a theoretical basis for further research of relevant feed additive criteria for this fish.

Bulk phase behaviour vs interface adsorption: Effects of anions and isotopes on β-lactoglobulin (BLG) interactions

HYPOTHESIS

Protein adsorption is highly relevant in numerous applications ranging from food processing to medical implants. In this context, it is important to gain a deeper understanding of protein-protein and protein-surface interactions. Thus, the focus of this investigation is on the interplay of bulk properties and surface properties on protein adsorption. It was hypothesised that the type of solvent and ions in solution should significantly influence the protein's bulk and interface behaviour, which has been observed in literature and previous work for other net negatively charged, globular proteins such as bovine serum albumin (BSA).

EXPERIMENTS

The phase behaviour of β-lactoglobulin (BLG) with lanthanum chloride (LaCl₃) and iodide (LaI₃) in normal water H₂O(l) and heavy water (D₂O(l)) was established via optical microscopy and ultraviolet-visible spectroscopy. The formation of an adsorption layer and its properties such as thickness, density, structure, and hydration was investigated via neutron reflectivity, quartz-crystal microbalance with dissipation, and infra-red measurements.

FINDINGS

β-lactoglobulin does not show significant anion-induced or isotope-induced effects - neither in bulk nor at the solid-liquid interface, which deviates strongly from the behaviour of bovine serum albumin. We also provide a comprehensive discussion and comparison of protein-specific bulk and interface behaviour between bovine serum albumin and β-lactoglobulin dependent on anion, cation, solvent, and substrate properties. These findings pave the way for understanding the transition from adsorption to crystallisation.

Ketamine-induced neurotoxicity in neurodevelopment: A synopsis of main pathways based on recent in vivo experimental findings

Ketamine, a phencyclidine derivative and N-methyl-D-aspartate (NMDA) receptor antagonist, is widely used as an anesthetic, analgesic, and sedative agent in daily pediatric practice. Experimental studies have suggested that early prenatal or postnatal exposure to ketamine can induce neuroapoptosis, and establish neurobehavioral deficits that are evident in adulthood. However, most of the currently available clinical evidence is derived from retrospective and observational clinical studies. We, herein, attempt a brief review of the cellular and molecular mechanisms suggested to mediate ketamine-induced developmental neurotoxicity, utilizing a selected number of recent in vivo experimental evidence.

Baseline characteristics, diagnostic efficacy, and peri-examinational safety of IV gadoteric acid MRI in 148,489 patients

BACKGROUND

Magnetic resonance imaging (MRI) examinations with intravenous (IV) contrast are performed worldwide in routine daily practice. In order to detect and enumerate even rare adverse events (AE) and serious adverse events (SAE), and to relate them with patients' baseline characteristics and diagnostic effectiveness, high quantity sample size is necessary.

PURPOSE

To assess safety, diagnostic effectiveness, and baseline characteristics of patients undergoing IV gadoteric acid (Dotarem®) MRI in routine practice.

MATERIAL AND METHODS

Data from two observational post-marketing surveillance (PMS) databases compiled by 139 and 52 German centers in 2004-2011 and 2011-2013, respectively, were pooled, yielding data on a total of 148,489 patients examined over a 10-year period. Radiologists used a standardized questionnaire to report data including patient demographics, characteristics of MR examinations, and results in terms of diagnosis and patient safety.

RESULTS

Overall, 712 AEs were reported in 467 (0.3%) patients, mainly nausea (n = 224, 0.2%), vomiting (n = 29, <0.1%), urticaria (n = 20, <0.1%), and feeling hot (n = 13, <0.1%). AEs were considered related to gadoteric acid in 362 (0.2%) patients. Higher frequencies of AEs were observed among patients with a previous reaction to a contrast agent (2.0%), liver dysfunction (0.7%), bronchial asthma (0.7%), and a history of allergies (0.6%). There were 49 SAEs in 18 (<0.1%) patients, including two children. No fatal SAE was reported. Examinations were diagnostic in 99.8% of all patients, and image quality was excellent or good in 97.7% of the patients.

CONCLUSION

Gadoteric acid is a safe peri-examinational and effective contrast agent for MRI in routine practice.

Human health risk associated with the management of phosphorus in freshwaters using lanthanum and aluminium

The use of geo-engineering materials to manage phosphorus in lakes has increased in recent years with aluminium and lanthanum based materials being most commonly applied. Hence the potential impact of the use of these compounds on human health is receiving growing interest. This review seeks to understand, evaluate and compare potential unintended consequences on human health and ecotoxicological risks associated with the use of lanthanum- and aluminium-based materials to modify chemical and ecological conditions in water bodies. In addition to their therapeutic use for the reduction of intestinal phosphate absorption in patients with impaired renal function, the phosphate binding capacity of aluminium and lanthanum also led to the development of materials used for water treatment. Although lanthanum and aluminium share physicochemical similarities and have many common applications, their uptake and kinetics within the human body and living organisms importantly differ from each other which is reflected in a different toxicity profile. Whilst a causal role in the development of neurological pathologies, skeletal lesions, hematopoietic disorders and respiratory effects has unequivocally been demonstrated with increased exposure to aluminium, studies until now have failed to find such a clear association after exposure to lanthanum although caution is warranted. Our review indicates that lanthanum and aluminium have a distinctly different profile with respect to their potential effects on human health. Regular monitoring of both aluminium and lanthanum concentrations in lanthanum-/aluminium-treated water by the responsible authorities is recommended to avoid acute accidental or chronic low level accumulation.

Physicians' awareness of gadolinium retention and MRI timing practices in the longitudinal management of pituitary tumors: a "Pituitary Society" survey

PURPOSE

In view of mounting attention related to possible brain retention of gadolinium-based contrast agents (GBCAs) in patients with normal renal function, our purpose was to detail results from a survey of pituitary experts to assess: 1) the timing interval and frequency of pituitary magnetic resonance imaging (MRI) following surgical and/or medical and/or radiation therapy of pituitary tumors, 2) awareness of the types of GBCAs used and their possible safety issues.

METHODS

The Pituitary Society Education Committee composed a survey with 12 multiple choice questions, 8 of which specifically addressed the time interval and frequency of MRI in the longitudinal management of pituitary tumors. The survey was distributed at two meetings; the International Pituitary Neurosurgeons Society conference in San Diego, CA, on February 18th, 2018, and the Pituitary Society Membership and Career Development Forum, Chicago, IL on March 18th, 2018.

RESULTS

There is consensus among pituitary endocrinologists and neurosurgeons that long-term repeated imaging is recommended in most pituitary tumors, although the precise strategy of timing varied depending on the specialist group and the specific clinical context of the adenoma. The data also suggest that International Pituitary Neurosurgeons Society neurosurgeons, as well as Pituitary Society neuroendocrinologists, are sometimes unaware of which contrast agents are used by their institution, and many are also unaware that evidence of long-term brain retention has been reported with the use of GBCAs in patients with normal function.

CONCLUSIONS

International pituitary endocrinologists and pituitary neurosurgeons experts suggest ongoing MRIs for the management of pituitary tumors; strategies vary based on clinical context, but also on individual experience and practice.

Gadolinium deposition and the potential for toxicological sequelae - A literature review of issues surrounding gadolinium-based contrast agents

Every year, approximately 30 million magnetic resonance imaging scans are enhanced with gadolinium-based contrast agents (GBCAs) worldwide. Although the development of nephrogenic systemic fibrosis in patients with renal impairment is well-documented, over recent years it has become apparent that exposure to GBCAs can potentially result in gadolinium deposition within human bone and brain tissue even in the presence of normal renal function. This review will address some of the controversies surrounding the safety of GBCA administration based on evidence from in vivo experiments, animal studies and clinical studies. We additionally evaluate the potential risk of toxicity from exposure to gadolinium in light of new guidance published by the US Food and Drug Administration and the European Medicines Agency, and discuss whether gadolinium deposition disease exists as a new diagnosis.

The effect of nuclear factor erythroid 2-related factor/antioxidant response element signalling pathway in the lanthanum chloride-induced impairment of learning and memory in rats

Lanthanum exerts adverse effects on the central nervous system. However, the mechanism underlying these adverse effects has not been clarified. It is known that oxidative stress plays an important role in neurological injuries induced by harmful factors. Nuclear factor erythroid 2-related factor (Nrf2) is very important in the response to oxidative stress in tissues and cells. The purpose of this study was to explore the effect of lanthanum chloride (LaCl₃ ) on the spatial learning and memory of rats and to determine whether the Nrf2/antioxidant response element pathway acts in the hippocampus. Four groups of Wistar rats were exposed to 0 mM, 9 mM, 18 mM or 36 mM LaCl₃ through their drinking water from the day of birth to 2 months after weaning. The results showed that LaCl₃ impaired the spatial learning and memory of the rats, damaged the neuronal ultrastructure, increased reactive oxygen species levels and significantly down-regulated Nrf2 as well as the mRNA and protein expression of Nrf2-regulated genes, including NADP(H): dehydrogenase quinone 1, haeme oxygenase-1, superoxide dismutase 2, glutathione peroxidase 1, glutathione-S-transferase, γ-glutamine cysteine synthase and glutathione reductase, in the hippocampus. This study suggests that LaCl₃ can impair the spatial learning and memory of rats, possibly by perturbing the Nrf2/antioxidant response element signalling pathway.

Activation of Nrf2/ARE signaling pathway attenuates lanthanum chloride induced injuries in primary rat astrocytes

Lanthanum (La) exposure can lead to learning and memory disorder in animals; however, the underlying mechanism of La induced neurotoxicity is still unknown.

Lanthanum nitrate genotoxicity evaluation: Ames test, mouse micronucleus assay, and chromosome aberration test

The increasing use of rare-earth elements (REE) and their compounds has led to their accumulation in the environment and has raised concern about their safety. The toxic effects of REE such as lanthanum are largely unknown; genotoxicity studies have been limited and results are controversial. We evaluated the genotoxicity of lanthanum nitrate (La(NO₃)₃) in several in vitro and in vivo tests, including bacterial reverse mutation assay (Ames test), mouse bone marrow micronucleus assay, and chromosome aberration assay. La(NO₃)₃ was not mutagenic in the Ames test. La(NO₃)₃ did not increase the frequencies of bone marrow micronuclei or chromosome aberration in the mouse after repeated treatments at oral doses up to 735 (females) and 855mg/kg (males). The compound did not increase the frequency of chromosome aberrations in CHO cells in vitro. These results indicate that lanthanum is not a genotoxic hazard.