The changes of serum zinc, copper, and selenium levels in epileptic patients: a systematic review and meta-analysis

Associations between blood selenium and serum neurofilament light chain: results of a nationwide survey

Background

Selenium (Se) is essential for many nervous system functions including memory, cognition and coordination, which has also been linked to a variety of neurological disorders, such as epilepsy, Alzheimer's disease (AD) and Parkinson's disease (PD). Serum neurofilament light chain (sNfL) is a biomarker of neurologic diseases. Studies on the relationship between blood Se and sNfL are limited.

Methods

The National Health and Nutrition Examination Survey (NHANES) 2013-2014 data were employed to perform multivariate linear regression analysis and smooth curve fitting in order to investigate the relationship between blood Se and sNfL. Utilizing subgroup analyses and interaction tests, the stability of this relationship between populations was evaluated.

Results

sNfL and blood Se had an inverse relationship in 1,036 individuals who were older than 20. According to the fully adjusted model, the sNfL decreased by 54.75 pg./mL for every unit increase in log blood Se [β = -54.75, 95% CI (-75.36, -34.14)]. The sNfL of individuals in the highest blood Se quartile decreased by 3.4 pg./mL in comparison to those in the lowest quartile [β = -3.40, 95% CI (-6.47, -0.32)]. This inverse association was more significant in those who were younger than 60 years old, male, normal weight, had a history of smoking and drinking.

Conclusion

Blood Se is inversely associated with sNfL in American adults. Our findings indicate that blood Se may have a potential protective effect against neuronal damage.

Correlation between selenium levels and selenoproteins expression in idiopathic generalized epilepsy: a study from Karachi

BACKGROUND

Oxidative damage has been implicated in multiple neurodegenerative diseases, including epilepsy. Selenium, in the form of selenoproteins is an integral part of the human antioxidant defense system. Though a relationship between the altered selenium levels and epilepsy has been reported, limited evidence is available about the expression pattern of selenoproteins in epileptic patients.

OBJECTIVE

This study aimed to determine the serum selenium levels in idiopathic epileptic and healthy individuals. Expression profiling of selenoproteins (GPx1, TRxR1 and SEPW1) both at mRNA and protein levels was also evaluated.

METHODS

Serum selenium levels of 30 patients with idiopathic generalized epilepsy and their age and gender matched 30 healthy controls were measured. Protein levels of Serum Glutathione Peroxidase 1 (GPx1), Thioredoxin Reductase 1 (TRxR1) and Selenoprotein W (SEPW1) were estimated using ELISA. mRNA expression of GPx1, TRxR1 and SEPW1 were determined using qRT-PCR.

RESULTS

The mean values for serum selenium levels in cases and controls were 37.6 ± 2.0 µmol/ml and 38.9 ± 2.7 µmol/ml, respectively. Selenium levels in cases were significantly lower as compared to controls (p = 0.031). No statistically significant differences were observed between the serum levels of selenoproteins GPx1, TRxR1 and SEPW1 in epileptic patients and the healthy group. GPx1 and TRxR1 expression was found to be down regulated (0.34 and 0.13 folds respectively) whereas SEPW 1 was found to be 0.04 folds up regulated in epileptic patients compared to the healthy subjects.

CONCLUSION

Selenium deficiency observed in epileptic patients suggests the association between serum selenium levels and epilepsy. This study provides the information about the selenium status in Pakistani population and helps in understanding the role of selenium in the prevention of epilepsy.

The Changes of Blood and CSF Ion Levels in Depressed Patients: a Systematic Review and Meta-analysis

Micronutrient deficiencies and excesses are closely related to developing and treating depression. Traditional and effective antidepressants include tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and lithium. There is no consensus on the fluctuation of zinc (Zn2+), magnesium (Mg2+), calcium (Ca2+), copper (Cu2+), iron (Fe2+), and manganese (Mn2+) ion levels in depressed individuals before and after therapy. In order to determine whether there were changes in blood and cerebrospinal fluid (CSF) levels of these ions in depressed patients compared with healthy controls and depressed patients treated with TCAs, SSRIs, or lithium, we applied a systematic review and meta-analysis. Using the Stata 17.0 software, we performed a systematic review and meta-analysis of the changes in ion levels in human samples from healthy controls, depressive patients, and patients treated with TCAs, SSRIs, and lithium, respectively. By searching the PubMed, EMBASE, Google Scholar, Web of Science, China National Knowledge Infrastructure (CNKI), and WAN FANG databases, 75 published analyzable papers were chosen. In the blood, the levels of Zn2+ and Mg2+ in depressed patients had decreased while the Ca2+ and Cu2+ levels had increased compared to healthy controls, Fe2+ and Mn2+ levels have not significantly changed. After treatment with SSRIs, the levels of Zn2+ and Ca2+ in depressed patients increased while Cu2+ levels decreased. Mg2+ and Ca2+ levels were increased in depressed patients after Lithium treatment. The findings of the meta-analysis revealed that micronutrient levels were closely associated with the onset of depression and prompted more research into the underlying mechanisms as well as the pathophysiological and therapeutic implications.

The Relationship of Fatigue and Depression with Trace Element Levels in Epileptic Patients

In this study, it was investigated whether there are trace element abnormalities in epileptic patients, the relationship of trace elements with fatigue and depression, and whether trace elements contribute to the development of fatigue and depression. A total of 87 people, 48 epileptic cases and 39 controls, were included in our study. Trace element levels of lead (Pb), zinc (Zn), copper (Cu), manganese (Mn), and selenium (Se) were measured in a single session on the study day by the same team. Beck Depression Inventory, Fatigue Severity Scale, Mood State Scale, and SF-36 Quality of Life scales were administered to all participants by the same person. The results were compared statistically. Depression rate was found as 35.4% and fatigue rate was 45.8% in epileptics. Se, Cu, and Mn levels were significantly higher in epileptics (p < 0.05), but there was no significant difference in Zn and Pb levels (p > 0.05). In the study, a moderate positive correlation was found between fatigue and depression (r = 0.346, p = 0.016). Fatigue severity scale (FSS) and Beck depression inventory (BDI) scores were found to be significantly higher in epileptics (p < 0.05). Total mood scale (TMS) mean score was compared between patient and control groups, and the difference between the groups was statistically significant (p < 0.005). It was observed that fatigue and depression are more common in epileptics, and there may be abnormalities in trace element plasma levels in epileptics, and it was determined that trace elements did not show a significant difference between those with and without fatigue and depression, and trace elements did not show a significant correlation with fatigue and depression.

Whole blood trace element and toxic metal concentration in dogs with idiopathic epilepsy and healthy dogs: A case-control study

Background

Idiopathic epilepsy (IE) is the most common neurological disease in dogs. Multiple genes and environmental factors interact to cause clinical signs, although the pathogenesis remains poorly understood. Extensive evidence from recent decades shows that trace elements play a role in epilepsy in humans, and recently it was shown for the first time that also dogs with IE have altered trace element status. On the other hand, toxic metals may cause seizures but research on their role in canine IE is lacking. Therefore, we aimed to investigate trace element and toxic metal concentrations in whole blood from dogs that had been diagnosed with IE and compare them to those of healthy dogs.

Materials and methods

Whole blood concentrations of trace elements (selenium, zinc, copper, manganese, iron, and chromium) and toxic metals (arsenic, cadmium, mercury, and lead) were analyzed from 19 dogs that had been diagnosed with IE by board-certified neurologists and 19 healthy control dogs using inductively coupled plasma mass spectrometry. The concentrations in study and control group were compared using the Mann-Whitney U test.

Results

Dogs diagnosed with IE had significantly higher blood copper concentration (P = 0.007), higher copper/zinc ratio (P = 0.04), and higher selenium concentration (P < 0.001), as well as lower chromium concentration (P = 0.01) when compared to healthy dogs. Treatment of IE with potassium bromide was associated with a significant elevation in blood arsenic concentration (P = 0.01).

Conclusion

In conclusion, the present results support the role of altered trace element status in dogs diagnosed with IE and suggest that copper, selenium, and chromium may be involved in the pathogenesis of canine epilepsy or seizures. The results also suggest that potassium bromide may alter arsenic metabolism in dogs.

Calcium-/Calmodulin-Dependent Protein Kinase II (CaMKII) Inhibition Induces Learning and Memory Impairment and Apoptosis

Objectives

Inhibition of calcium-/calmodulin- (CaM-) dependent kinase II (CaMKII) is correlated with epilepsy. However, the specific mechanism that underlies learning and memory impairment and neuronal death by CaMKII inhibition remains unclear.

Materials and Methods

In this study, KN93, a CaMKII inhibitor, was used to investigate the role of CaMKII during epileptogenesis. We first identified differentially expressed genes (DEGs) in primary cultured hippocampal neurons with or without KN93 treatment using RNA-sequencing. Then, the impairment of learning and memory by KN93-induced CaMKII inhibition was assessed using the Morris water maze test. In addition, Western blotting, immunohistochemistry, and TUNEL staining were performed to determine neuronal death, apoptosis, and the relative signaling pathway.

Results

KN93-induced CaMKII inhibition decreased cAMP response element-binding (CREB) protein activity and impaired learning and memory in Wistar and tremor (TRM) rats, an animal model of genetic epilepsy. CaMKII inhibition also induced neuronal death and reactive astrocyte activation in both the Wistar and TRM hippocampi, deregulating mitogen-activated protein kinases. Meanwhile, neuronal death and neuron apoptosis were observed in PC12 and primary cultured hippocampal neurons after exposure to KN93, which was reversed by SP600125, an inhibitor of c-Jun N-terminal kinase (JNK).

Conclusions

CaMKII inhibition caused learning and memory impairment and apoptosis, which might be related to dysregulated JNK signaling.

The Zinc-Sensing Receptor GPR39 in Physiology and as a Pharmacological Target

The G-protein coupled receptor GPR39 is abundantly expressed in various tissues and can be activated by changes in extracellular Zn²⁺ in physiological concentrations. Previously, genetically modified rodent models have been able to shed some light on the physiological functions of GPR39, and more recently the utilization of novel synthetic agonists has led to the unraveling of several new functions in the variety of tissues GPR39 is expressed. Indeed, GPR39 seems to be involved in many important metabolic and endocrine functions, but also to play a part in inflammation, cardiovascular diseases, saliva secretion, bone formation, male fertility, addictive and depression disorders and cancer. These new discoveries offer opportunities for the development of novel therapeutic approaches against many diseases where efficient therapeutics are still lacking. This review focuses on Zn²⁺ as an endogenous ligand as well as on the novel synthetic agonists of GPR39, placing special emphasis on the recently discovered physiological functions and discusses their pharmacological potential.