Subcellular distribution of phospholipids during liver damage induced by rare earths

Association between concentrations of rare earth elements in chorionic villus and risk for unexplained spontaneous abortion

Rare earth elements (REEs) exposure during pregnancy may increase the risk of unexplained spontaneous abortion. However, the association between REEs intrauterine exposure and unexplained spontaneous abortion had yet to be studied. In order to conduct this large case-control study, we thus collected chorionic villus from 641 unexplained spontaneous abortion and 299 control pregnant women and detected the concentrations of 15 REEs by inductively coupled plasma mass spectrometer (ICP-MS). Because the detection rates of 10 REEs were less than 80%, the remaining 5 REEs, which were lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd) and yttrium (Y), underwent to further analysis. The association between 5 REEs and unexplained spontaneous abortion was assessed by using the logistic regression, bayesian kernel regression (BKMR) and weighted quantile sum regression (WQS) models. In the adjusted logistic regression model, Pr, Nd and Y enhanced the incidence of unexplained spontaneous abortion in a dose-dependent way and Ce increased the risk only at high concentration group. The result of BKMR model demonstrated that the risk of unexplained spontaneous abortion increased as the percentile of five mixed REEs increased. Y and Nd were both significantly associated with an increased incidence of unexplained spontaneous abortion, but La was correlated with a decrease in the risk of unexplained spontaneous abortion. Pr was substantially associated with an increase in the risk of unexplained spontaneous abortion when other REEs concentrations were fixed at the 25th and 50th percentiles. According to WQS regression analysis, the WQS index was significantly associated with unexplained spontaneous abortion (OR = 3.75, 95% CI:2.40-5.86). Y had the highest weight, followed by Nd and Pr, which was consistent with the analysis results of our other two models. In short, intrauterine exposure to REEs was associated with an increased risk of unexplained spontaneous abortion, with Y, Nd and Pr perhaps playing an essential role.

Correlation between urinary rare earth elements and liver function in a Zhuang population aged 35-74 years in Nanning

BACKGROUND

Animal studies have shown that exposure to REEs can cause severe liver damage, but evidence from population studies is still lacking. Therefore, we investigated the relationship between REEs concentrations in urine and liver function in the population.

METHODS

We conducted a cross-sectional study on 1024 participants in Nanning, China. An inductively coupled plasma mass spectrometer (ICP-MS) was used to detect the concentrations of 12 REEs in urine. The relationship between individual exposure to individual REE and liver function was analyzed by multiple linear regression. Finally, the effects of co-exposure to 5 REEs on liver function were assessed by a weighted sum of quartiles (WQS) regression model and a Bayesian kernel machine regression (BKMR) model.

RESULTS

The detection rate of 5 REEs, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), and dysprosium (Dy), is greater than 60%. After multiple factor correction, La, Ce, Pr, Nd, and Dy were positively correlated with serum ALP, Ce, Pr, and Nd were positively correlated with serum AST, while Ce was negatively correlated with serum TBIL and DBIL. Both WQS and BKMR results indicate that the co-exposure of the 5 REEs is positively correlated with serum ALP and AST, while negatively correlated with serum DBIL. There were potential interactions between La and Ce, La and Dy in the association of co-exposure of the 5 REEs with serum ALP.

CONCLUSIONS

The co-exposure of the 5 REEs was positively correlated with serum ALP and AST, and negatively correlated with serum DBIL.

Organ histopathological changes and its function damage in mice following long-term exposure to lanthanides chloride

Due to increasing applications of lanthanides (Ln) in industry and daily life, numerous studies confirmed that Ln exposure may result in organ damages in mice and rats, while very few studies focused on several organs damages simultaneously. In order to compare the toxicity of Ln on organs, mice were exposed to LaCl(3), CeCl(3), and NdCl(3) of a dose of 20 mg/kg body weight for consecutive 60 days, respectively, then histopathological changes of liver, kidney, and heart, and their function were investigated. The results showed that long-term exposure to Ln caused cell necrosis and basophilia of liver, ambiguity of renal tubule architecture, congestion of blood vessel and capillary of kidney, and heart hemorrhage. The histopathological changes of liver, kidney, and heart in mice caused by Ce(3+) was most severe; the effect by Nd(3+) was slighter than Ce(3+) but more severe than La(3+). The assay of serum biochemical parameters suggested that Ln exposure severely impaired the functions of liver, kidney, and myocardium in mice. These findings suggested that long-term exposure to Ln resulted in histopathological changes of liver, kidney, and heart, and their function damages. Therefore, we thought that long-term application of the products containing Ln on human should be cautious.

The mechanism of liver injury in mice caused by lanthanoids

It has been proven that higher dose of lanthanoid (Ln) can induce liver toxicities, but the mechanisms and the molecular pathogenesis are still unclear. In this study, LaCl₃, CeCl₃, and NdCl₃ at a higher dose of 20 mg/kg body weight was injected into the abdominal cavity of ICR mice for 14 consecutive days, and the inflammatory responses of liver of mice were investigated by histopathological test, real-time quantitative reverse transcription polymerase chain reaction (RT-PCR), and enzyme-linked immunosorbent assay (ELISA) methods. The results showed the significant accumulation of Ln in the liver results in liver histopathological changes and, therefore, liver malfunctions. The real-time quantitative RT-PCR and ELISA analyses showed that Ln could significantly alter the mRNA and protein expressions of several inflammatory cytokines, including nucleic factor-κB, macrophage migration inhibitory factor, tumor necrosis factor-α, interleukin-1β, interleukin-6, cross-reaction protein, interleukin-4, and interleukin-10. Our results also implied that the inflammatory responses and liver injury likely are caused by 4f shell and alterable valence properties of Ln-induced liver toxicity.

Metal ion release from paramagnetic chelates: what is tolerable?

At the currently administered clinical doses, paramagnetic metal chelate complexes presently used as MR contrast enhancement agents appear to be relatively nontoxic. Solution thermodynamic, solubility, and selectivity studies, based on a number of gadolinium chelate complexes, indicate that very little gadolinium is released in vivo, and the small amounts that do remain are available for excretion, albeit slowly. Although the mechanism of metal release from manganese-based chelate complexes is not well understood, any released manganese is likely to be quickly and efficiently cleared through the liver. Although MRI contrast agents are unlikely to be administered repeatedly in patients, which could result in accumulation of metal ion, the long-term effects of such potential deposition have yet to be demonstrated.

Effect of praseodymium chloride on liver microsomal enzymes of rats

A single i.v. dose (5 mg/kg) of a light lanthanon, praseodymium, prolonged the duration of hexobarbital-induced sleep and zoxazolamine-induced paralysis, as well as it modified pharmacokinetic parameters of hexobarbital and zoxazolamine, in rats. Half-lives (t1/2) and area under the curve (AUC) were increased, while elimination coefficient (beta) and clearance (Cl) were decreased. However, in daily doses of 1 mg/kg i.p. for 15 days, praseodymium did not alter pharmacological effects and pharmacokinetic parameters. The in vitro hydroxylation of hexobarbital and zoxazolamine by liver microsomes was inhibited when the animals were treated previously with a single i.v. dose (5 mg/kg) of praseodymium chloride. In these animals, the amount of cytochromes P-450 and b5 were reduced significantly, whereas that of NADPH-cytochrome c reductase remained unchanged. The pretreatment of animals with phenobarbital normalized the microsomal enzyme impairment caused by praseodymium.

Effect of praseodymium on drug metabolism in rat liver smooth and rough endoplasmic reticulum

A small i.v. dose (3 mg/kg) of a light lanthanon, praseodymium, impairs the drug metabolizing capacity of both the smooth and rough fractions of rat liver endoplasmic reticulum. This decrease in the activity of drug metabolizing enzymes and in the amount of cytochromes P-450 and b5 is more pronounced in the rough endoplasmic reticulum fraction.