Metallomic Biomarkers in Cerebrospinal fluid and Serum in patients with Parkinson's disease in Indian population

Neuroinflammation-mediated white matter injury in Parkinson's disease and potential therapeutic strategies targeting NLRP3 inflammasome

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world, severely affecting the quality of life of patients. Recent studies have shown that white matter (WM) plays a vital role in higher neurological functions such as behavior and cognition. In PD patients, neurodegeneration occurs not only in neuronal soma, but also in WM fiber bundles, which are composed of neural axons. The clinical symptoms of PD patients are related not only to the degeneration of neuronal soma, but also to the degeneration of WM. Most previous studies have focused on neuronal soma in substantia nigra (SN), while WM injury (WMI) in PD has been less studied. Moreover, most previous studies have focused on intracerebral lesions in PD, while less attention has been paid to the spinal cord distal to the brain. The above-mentioned factors may be one of the reasons for the poor treatment of previous drug outcomes. Neuroinflammation has been shown to exert a significant effect on the pathological process of brain and spinal cord neurodegeneration in PD. The NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome has been shown to activate and mediate neuroinflammation and exacerbate neurodegeneration in PD. NLRP3 inflammasome inhibition may be a potential strategy for the treatment of WMI in PD. This review summarizes recent advances and future directions regarding neuroinflammation-mediated WMI in PD and potential therapeutic strategies for targeting NLRP3 inflammasome in the brain and spinal cord, providing new insights for researchers to develop more effective therapeutic approaches for PD patients.

An Update Overview on Mechanistic Data and Biomarker Levels in Cobalt and Chromium-Induced Neurodegenerative Diseases

There is increasing evidence that the imbalance of metals as cobalt (Co) and chromium (Cr) may increase the risk of development and progression of neurodegenerative diseases (NDDs). The human exposure to Co and Cr is derived mostly from industry, orthopedic implants, and polluted environments. Neurological effects of Co and Cr include memory deficit, olfactory dysfunction, spatial disorientation, motor neuron disease, and brain cancer. Mechanisms of Co and Cr neurotoxicity included DNA damage and genomic instability, epigenetic changes, mitochondrial disturbance, lipid peroxidation, oxidative stress, inflammation, and apoptosis. This paper seeks to overview the Co and Cr sources, the mechanisms by which these metals induce NDDs, and their levels in fluids of the general population and patients affected by NDDs. To this end, evidence of Co and Cr unbalance in the human body, mechanistic data, and neurological symptoms were collected using in vivo mammalian studies and human samples.

The Role of Magnesium in Parkinson's Disease: Status Quo and Implications for Future Research

Neurodegenerative diseases represent an increasing economic, social, and, above all, medical burden worldwide. The second most prevalent disease in this category is Parkinson's disease, surpassed only by Alzheimer's. It is a treatable but still incurable systemic disease with a pathogenesis that has not yet been elucidated. Several theories are currently being developed to explain the causes and progression of Parkinson's disease. Magnesium is one of the essential macronutrients and is absolutely necessary for life as we know it. The magnesium cation performs several important functions in the cell in the context of energetic metabolism, substrate metabolism, cell signalling, and the regulation of the homeostasis of other ions. Several of these cellular processes have been simultaneously described as being disrupted in the development and progression of Parkinson's disease. The relationship between magnesium homeostasis and the pathogenesis of Parkinson's disease has received little scientific attention to date. The aim of this review is to summarise and critically evaluate the current state of knowledge on the possible role of magnesium in the pathogenesis of Parkinson's disease and to outline possible future directions for research in this area.

Intricate subcellular journey of nanoparticles to the enigmatic domains of endoplasmic reticulum

It is evident that site-specific systemic drug delivery can reduce side effects, systemic toxicity, and minimal dosage requirements predominantly by delivering drugs to particular pathological sites, cells, and even subcellular structures. The endoplasmic reticulum (ER) and associated cell organelles play a vital role in several essential cellular functions and activities, such as the synthesis of lipids, steroids, membrane-associated proteins along with intracellular transport, signaling of Ca2+, and specific response to stress. Therefore, the dysfunction of ER is correlated with numerous diseases where cancer, neurodegenerative disorders, diabetes mellitus, hepatic disorder, etc., are very common. To achieve satisfactory therapeutic results in certain diseases, it is essential to engineer delivery systems that can effectively enter the cells and target ER. Nanoparticles are highly biocompatible, contain a variety of cargos or payloads, and can be modified in a pliable manner to achieve therapeutic effectiveness at the subcellular level when delivered to specific organelles. Passive targeting drug delivery vehicles, or active targeting drug delivery systems, reduce the nonselective accumulation of drugs while reducing side effects by modifying them with small molecular compounds, antibodies, polypeptides, or isolated bio-membranes. The targeting of ER and closely associated organelles in cells using nanoparticles, however, is still unsymmetrically understood. Therefore, here we summarized the pathophysiological prospect of ER stress, involvement of ER and mitochondrial response, disease related to ER dysfunctions, essential therapeutics, and nanoenabled modulation of their delivery to optimize therapy.

Metal Exposure and Risk of Parkinson Disease: A Systematic Review and Meta-Analysis

Metal exposure has been suggested as a possible environmental risk factor for Parkinson disease (PD). We searched the PubMed, EMBASE, and Cochrane databases to systematically review the literature on the relationship between metal exposure and PD risk and to examine the overall quality of each study and the exposure assessment method. A total of 83 case-control studies and 5 cohort studies published during the period 1963-July 2021 were included, of which 73 were graded as being of low or moderate overall quality. Investigators in 69 studies adopted self-reported exposure and biomonitoring after disease diagnosis for exposure assessment approaches. The meta-analyses showed that concentrations of copper and iron in serum and concentrations of zinc in either serum or plasma were lower, while concentrations of magnesium in CSF and zinc in hair were higher, among PD cases as compared with controls. Cumulative lead levels in bone were found to be associated with increased risk of PD. We did not find associations between other metals and PD. The current level of evidence for associations between metals and PD risk is limited, as biases from methodological limitations cannot be ruled out. High-quality studies assessing metal levels before disease onset are needed to improve our understanding of the role of metals in the etiology of PD.

Eleven Crucial Pesticides Appear to Regulate Key Genes That Link MPTP Mechanism to Cause Parkinson's Disease through the Selective Degeneration of Dopamine Neurons

Pesticides kill neurons, but the mechanism leading to selective dopaminergic loss in Parkinson's disease (PD) is unknown. Understanding the pesticide's effect on dopaminergic neurons (DA) can help to screen and treat PD. The critical uptake of pesticides by the membrane receptors at DA is hypothesized to activate a signaling cascade and accelerate degeneration. Using MPTP as a reference, we demonstrate the mechanisms of eleven crucial pesticides through molecular docking, protein networks, regulatory pathways, and prioritization of key pesticide-regulating proteins. Participants were recruited and grouped into control and PD based on clinical characteristics as well as pesticide traces in their blood plasma. Then, qPCR was used to measure pesticide-associated gene expression in peripheral blood mononuclear cells between groups. As a result of molecular docking, all eleven pesticides and the MPTP showed high binding efficiency against 274 membrane receptor proteins of DA. Further, the protein interaction networks showed activation of multiple signaling cascades through these receptors. Subsequent analysis revealed 31 biological pathways shared by all 11pesticides and MPTP that were overrepresented by 46 crucial proteins. Among these, CTNNB1, NDUFS6, and CAV1 were prioritized to show a significant change in gene expression in pesticide-exposed PD which guides toward therapy.

Meta-analysis of iron metabolism markers levels of Parkinson's disease patients determined by fluid and MRI measurements

BACKGROUND

Parkinson' s disease (PD) is a progressive neurodegenerative disease featured neuropathologically by the loss of dopaminergic neurons of the substantia nigra (SN). Iron overload in the SN is mainly relative to the pathology and pathogenesis of PD. Postmortem samples of PD has indicated the increased levels of brain iron. However, there is no consensus on iron content through iron-sensitive magnetic resonance imaging (MRI) techniques and the alteration of iron and iron related metabolism markers levels in blood and cerebrospinal fluids (CSF) are still unclear based on the current studies. In this study, we performed a meta-analysis to explore the iron concentration and iron metabolism markers levels through iron-sensitive MRI quantification and body fluid.

METHODS

A comprehensive literature search was performed in PubMed, EMBASE and Cochrane Library databases for relevant published studies that analyzed iron load in the SN of PD patients using quantitative susceptibility mapping (QSM) or susceptibility weighting imaging (SWI), and iron metabolism markers, iron, ferritin, transferrin, total iron-binding capacity（TIBC）in CSF sample or serum/plasma sample (from Jan 2010 to Sep 2022 to filter these inaccurate researches attributed to unadvanced equipment, inaccurate analytical methods). Standardized mean differences (SMD) or mean differences (MD) and 95% confidence intervals (CI) with random or fixed effect model was used to estimate the results.

RESULTS

Forty-two articles fulfilled the inclusion criteria including 19 for QSM, 6 for SWI, and 17 for serum/plasma/CSF sample including 2874 PD patients and 2821 healthy controls (HCs). Our meta-analysis results founded a notable difference for QSM values increase (19.67, 95% CI=18.69-20.64) and for SWI measurements (-1.99, 95% CI= -3.52 to -0.46) in the SN in PD patients. However, the serum/plasma/CSF iron levels and serum/plasma ferritin, transferrin, total iron-binding capacity (TIBC) did not differ significantly between PD patients and HCs.

CONCLUSIONS

Our meta-analysis showed the consistent increase in the SN in PD patients using QSM and SWI techniques of iron-sensitive MRI measures while no significant differences were observed in other iron metabolism markers levels.

The effect of hypocalcemia on motor symptoms of Parkinson’s disease

Background

The disabling nature of Parkinson’s disease (PD) impairs functional mobility and worsens quality of life. Calcium imbalances are thought to have a significant role in the progression of PD.

Objective

To evaluate the relation between calcium deficiency and deterioration of PD motor symptoms.

Methods

A total of 28 idiopathic PD patients were subjected to motor symptoms evaluation using the modified Hoehn–Yahr scale (H–Y), Unified Parkinson’s Disease Rating Scale (UPDRS) Part II and III and Schwab and England Activities of Daily Living Scale (S–E ADL). Total and ionized serum calcium levels were measured for the PD patients and the 30 healthy control subjects.

Results

The level of ionized calcium was significantly lower among PD patients (4.19 mg/dl ± 0.53) than in control subjects (4.8 mg/dl ± 0.35) (p < 0.0001). The PD patients with hypocalcemia showed marked deterioration of motor symptoms and significant impairment of daily life activities when compared to PD patients with normal calcium levels regarding their scores on the modified H–Y scale (p = 0.001), UPDRS-III (p = 0.001), UPDRS-II (p = 0.001), and S–E ADL scale (p = 0.001). Ionized calcium correlated significantly with PD patients’ scores on the modified H–Y scale (p = 0.019), UPDRS-Part II (p = 0.001), UPDRS-Part III (p = 0.001) and S–E ADL scale (p = 0.001). The significant cutoff point of the ionized calcium for detection of the deteriorated PD patients that presented with stages more than grade 2 of the modified H–Y scale was < 3.99 (p = 0.037) with a sensitivity of 80% and specificity of 95%.

Conclusions

Our findings conclude that calcium deficiency could contribute to the deterioration of PD motor symptoms.

Impact of Environmental Risk Factors on Mitochondrial Dysfunction, Neuroinflammation, Protein Misfolding, and Oxidative Stress in the Etiopathogenesis of Parkinson's Disease

As a prevalent progressive neurodegenerative disorder, Parkinson's disease (PD) is characterized by the neuropathological hallmark of the loss of nigrostriatal dopaminergic (DAergic) innervation and the appearance of Lewy bodies with aggregated α-synuclein. Although several familial forms of PD have been reported to be associated with several gene variants, most cases in nature are sporadic, triggered by a complex interplay of genetic and environmental risk factors. Numerous epidemiological studies during the past two decades have shown positive associations between PD and several environmental factors, including exposure to neurotoxic pesticides/herbicides and heavy metals as well as traumatic brain injury. Other environmental factors that have been implicated as potential risk factors for PD include industrial chemicals, wood pulp mills, farming, well-water consumption, and rural residence. In this review, we summarize the environmental toxicology of PD with the focus on the elaboration of chemical toxicity and the underlying pathogenic mechanisms associated with exposure to several neurotoxic chemicals, specifically 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, paraquat (PQ), dichloro-diphenyl-trichloroethane (DDT), dieldrin, manganese (Mn), and vanadium (V). Our overview of the current findings from cellular, animal, and human studies of PD provides information for possible intervention strategies aimed at halting the initiation and exacerbation of environmentally linked PD.

Influence of heavy metals in Parkinson's disease: an overview

Parkinson's disease (PD) is an ageing disorder with deterioration of dopamine neurons which leads to motor complications like tremor, stiffness, slow movement and postural disturbances. In PD, both genetics as well as environmental factors both play a major role in causing the pathogenesis. Though there are surfeit of risk factors involved in PD occurrence, till now there is lack of an exact causative agent as a risk for PD with confirmative findings. The role of heavy metals reported to be a significant factor in PD pathogenesis. Heavy metal functions in cell maintenance but growing pieces of evidences reported to cause dyshomeostasis with increased PD rate. Metals disturb the molecular processes and results in oxidative stress, DNA damage, mitochondrial dysfunction, and apoptosis. The present review elucidates the role of cobalt, nickel, mercury, chromium, thallium metals in α-synuclein aggregation and its involvement in blood brain barrier flux. Also, the review explains the plausible role of aforementioned metals with a mechanistic approach and therapeutic recommendations in PD.

Isoliquiritigenin attenuates neuroinflammation in mice model of Parkinson's disease by promoting Nrf2/NQO-1 pathway

Parkinson's disease (PD) is a common neurodegenerative disease that severely affects the quality of life of patients. There is no specific drug for PD up to now. Previous studies have shown that neuroinflammation plays an important role in the pathogenesis of PD. Isoliquiritigenin (ILG) is thought to have a variety of biological activities including anti-inflammatory. However, to date, no studies have reported the role of ILG on neuroinflammation in PD in vivo. This study aimed to investigate the effect of ILG on PD in vivo and its mechanism, and to provide an experimental basis for clinical treatment of PD. Our results showed that ILG at a concentration of 20 mg/kg was effective in reducing the number of rotations in PD mice. In addition, ILG increased the expression of tyrosine hydroxylase and decreased the expression of α-synuclein. The results also showed that ILG reduced the expression of Iba1, IL-1β, IL-6, and TNF-α. Not only that, ILG also upregulated the expression of Nrf2 and NQO-1 in vivo. Our results suggest that ILG significantly attenuates neurological deficits in PD, and the mechanism may be through the activation of the Nrf2/NQO-1 signaling pathway to reduce neuroinflammation. Moreover, our findings provide a new therapeutic strategy for PD.

Biological fluid levels of iron and iron-related proteins in Parkinson's disease: Review and meta-analysis

BACKGROUND AND PURPOSE

Several studies suggested a role or iron in the pathogenesis or Parkinson's disease (PD), and substantia nigra iron concentrarions have been found increased in PD. However, the results on cerebrospinal (CSF) and serum/plasma iron levels in PD patients have been controversial. The aim of this systematic review and meta-analysis was to establish the CSF and serum/plasma levels of iron and iron-related proteins (ferritin, transferrin, lactoferrin, haptoglobin, and hepcidine) levels, and the urine levels of iron, in patients with PD.

METHODS

Four databases (PubMed, EMBASE, MedLine, and Web of Science - Core Collection) were reviewed for studies published from 1966 to October 5, 2020. References of interest were identified. A meta-analysis of eligible studies was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines, using the R software package meta.

RESULTS

A non-significant trend towards higher CSF iron levels and marginally significantly lower serum/plasma iron levels was observed in patients with PD compared with age- and sex-matched controls. CSF and serum/plasma ferritin and transferrin concentrations, and serum/plasma lactoferrin and haptoglobin concentrations did not differ significantly between PD patients and controls.

CONCLUSION

The findings of this study suggest an association between decreased serum/plasma iron levels and, possibly, higher CSF iron levels with risk of PD.

Interdependence of metals and its binding proteins in Parkinson's disease for diagnosis

Metalloproteins utilizes cellular metals which plays a crucial function in brain that linked with neurodegenerative disorders. Parkinson's disease (PD) is a neurodegenerative disorder that affects geriatric population world-wide. Twenty-four metal-binding protein networks were investigated to identify key regulating protein hubs in PD blood and brain. Amongst, aluminum, calcium, copper, iron, and magnesium protein hubs are the key regulators showing the ability to classify PD from control based on thirty-four classification algorithms. Analysis of these five metal proteins hubs showed involvement in environmental information processing, immune, neuronal, endocrine, aging, and signal transduction pathways. Furthermore, gene expression of functional protein in each hub showed significant upregulation of EFEMP2, MMP9, B2M, MEAF2A, and TARDBP in PD. Dysregulating hub proteins imprint the metal availability in a biological system. Hence, metal concentration in serum and cerebrospinal fluid were tested, which were altered and showed significant contribution towards gene expression of metal hub proteins along with the previously reported PD markers. In conclusion, analyzing the levels of serum metals along with the gene expression in PD opens up an ideal and feasible diagnostic intervention for PD. Hence, this will be a cost effective and rapid method for the detection of Parkinson's disease.

Disease Ionomics: Understanding the Role of Ions in Complex Disease

Ionomics is a novel multidisciplinary field that uses advanced techniques to investigate the composition and distribution of all minerals and trace elements in a living organism and their variations under diverse physiological and pathological conditions. It involves both high-throughput elemental profiling technologies and bioinformatic methods, providing opportunities to study the molecular mechanism underlying the metabolism, homeostasis, and cross-talk of these elements. While much effort has been made in exploring the ionomic traits relating to plant physiology and nutrition, the use of ionomics in the research of serious diseases is still in progress. In recent years, a number of ionomic studies have been carried out for a variety of complex diseases, which offer theoretical and practical insights into the etiology, early diagnosis, prognosis, and therapy of them. This review aims to give an overview of recent applications of ionomics in the study of complex diseases and discuss the latest advances and future trends in this area. Overall, disease ionomics may provide substantial information for systematic understanding of the properties of the elements and the dynamic network of elements involved in the onset and development of diseases.

Shared perturbations in the metallome and metabolome of Alzheimer's, Parkinson's, Huntington's, and dementia with Lewy bodies: A systematic review

Despite differences in presentation, age-related dementing diseases such as Alzheimer's (AD), Parkinson's (PD), and Huntington's diseases (HD), and dementia with Lewy bodies (DLB) may share pathogenic processes. This review aims to systematically assemble and compare findings in various biochemical pathways across these four dementias. PubMed and Google Scholar were screened for articles reporting on brain and biofluid measurements of metals and/or metabolites in AD, PD, HD, or DLB. Articles were assessed using specific a priori-defined inclusion and exclusion criteria. Of 284 papers identified, 198 met criteria for inclusion. Although varying coverage levels of metals and metabolites across diseases and tissues made comparison of many analytes impossible, several common findings were identified: elevated glucose in both brain tissue and biofluids of AD, PD, and HD cases; increased iron and decreased copper in AD, PD and HD brain tissue; and decreased uric acid in biofluids of AD and PD cases. Other analytes were found to differ between diseases or were otherwise not covered across all conditions. These findings indicate that disturbances in glucose and purine pathways may be common to AD, PD, and HD. However, standardisation of methodologies and better coverage in some areas - notably of DLB - are necessary to validate and extend these findings.

Delineating colorectal cancer distribution, interaction, and risk prediction by environmental risk factors and serum trace elements

The burden of colorectal cancer (CRC) is increasing worldwide especially in developing countries. This phenomenon may be attributable to lifestyle, dietary and environmental risk factors. We aimed to determine the level of 25 trace elements, their interaction with environmental risk factors, and subsequently develop a risk prediction model for CRC (RPM CRC). For the discovery phase, we used a hospital-based case-control study (CRC and non-CRC patients) and in the validation phase we analysed pre-symptomatic samples of CRC patients from The Malaysian Cohort Biobank. Information on the environmental risk factors were obtained and level of 25 trace elements measured using the ICP-MS method. CRC patients had lower Zn and Se levels but higher Li, Be, Al, Co, Cu, As, Cd, Rb, Ba, Hg, Tl, and Pb levels compared to non-CRC patients. The positive interaction between red meat intake ≥ 50 g/day and Co ≥ 4.77 µg/L (AP 0.97; 95% CI 0.91, 1.03) doubled the risk of CRC. A panel of 24 trace elements can predict simultaneously and accurate of high, moderate, and low risk of CRC (accuracy 100%, AUC 1.00). This study provides a new input on possible roles for various trace elements in CRC as well as using a panel of trace elements as a screening approach to CRC.

Clinical utility of brain-derived neurotrophic factor as a biomarker with left ventricular echocardiographic indices for potential diagnosis of coronary artery disease

Brain-derived neurotrophic factor (BDNF) plays a central pivotal role in the development of the cardiovascular system. Recent evidence suggests that BDNF has adverse subclinical cardiac remodeling in participants with cardiovascular disease risk factors. Relating serum BDNF levels with two-dimensional echocardiographic indices will provide insights into the BDNF mediated pathophysiology in coronary artery disease (CAD) that may shed light upon potential diagnostic biomarkers. For the study, 221 participants were recruited and classified based on coronary angiogram examination as control (n = 105) and CAD (n = 116). All participants underwent routine blood investigation, two-dimensional echocardiography, and serum BDNF estimation. As a result, total cholesterol, triglyceride, low-density lipid, high-density lipid, HbA1c (glycosylated hemoglobin), serum creatinine, eosinophils, lymphocyte, monocytes, neutrophils, and platelets were significantly elevated in CAD individuals compared to controls. Notably, the serum BDNF was significantly lower in individuals with CAD (30.69 ± 5.45 ng/ml) than controls (46.58 ± 7.95 ng/ml). Multivariate regression analysis showed neutrophils, total cholesterol, left ventricular mass index, mitral inflow E/A ratio, and pulmonary vein AR duration were associated with low BDNF in CAD. Four independent support vector machine (SVM) models performed to ensure the BDNF level in the classification of CAD from healthy controls. Particularly, the model with serum BDNF concentration and blood parameters of CAD achieved significant improvement from 90.95 to 98.19% in detecting CAD from healthy controls. Overall, our analysis provides a significant molecular linkage between the serum BDNF level and cardiovascular function. Our results contribute to the emerging evidence of BDNF as a potential diagnostic value in CAD that might lead to clinical application.

PARK2 and PARK7 Gene Polymorphisms as Risk Factors Associated with Serum Element Concentrations and Clinical Symptoms of Parkinson's Disease

Besides clinical and imaging techniques, there is a lack of molecular makers for the diagnosis of Parkinson's disease (PD). There is an immense need to develop biomarkers associated with the phenotypes which may be valuable for individualized treatment. Single-nucleotide polymorphisms (PARK2: Ser167Asn (G>A) and Val380Leu (G>C); PARK7: IVS4 + 46G>A and IVS4 + 30T>G) in PD-related genes were examined to elucidate its relationship with concentration of serum elements and clinical symptoms of PD. A total of 214 PD patients and 213 controls from Indian population were genotyped using PCR and DNA sequencing methods. The serum element concentrations were detected and clinical symptoms were determined based on UPDRS scale and recorded at the time of sample collection. The IVS4 + 30T>G, Ser167Asn (G>A) and Val380Leu (G>C) polymorphisms appeared to alter element concentrations in PD. The patients with Ser167Asn polymorphism showed significant association with copper, iron and zinc that reinforces the role of A allele as a factor for change in the concentrations of elements, than those patients with G allele. In particular, patients with A allele of Ser167Asn have risk of having high serum iron concentration (OR 11.55, 95% CI 5.59-23.85), which are associated with dementia and postural imbalance. Similar results were observed for Val380Leu (G>C) and IVS4 + 30T>G polymorphisms which suggest their role in element concentration and neurological symptoms. Overall, our study demonstrates the influence of polymorphisms of PD genes on element concentrations and clinical symptoms. Results of this study may be taken into account when considering the contributing factors for PD symptoms.

Simultaneous analysis of 25 trace elements in micro volume of human serum by inductively coupled plasma mass spectrometry (ICP-MS)

INTRODUCTION

In recent years, trace elements have gained importance as biomarkers in many chronic diseases. Unfortunately, the requirement for sample volume increases with the extent of investigation either for diagnosis or elucidating the mechanism of the disease. Here, we describe the method development and validation for simultaneous determination of 25 trace elements (lithium [Li], beryllium [Be], magnesium [Mg], aluminium [Al], vanadium [V], chromium [Cr], manganese [Mn], iron [Fe], cobalt [Co], nickel [Ni], copper [Cu], zinc [Zn], gallium [Ga], arsenic [As], selenium [Se], rubidium [Rb], strontium [Sr], silver [Ag], cadmium [Cd], caesium [Cs], barium [Ba], mercury [Hg], thallium [Tl], lead [Pb], uranium [U]) using only 20 μL of human serum.

METHODS

Serum samples were digested with nitric acid and hydrochloric acid (ratio 1:1, v/v) and analysed by inductively coupled plasma-mass spectrometry (ICP-MS). Seronorm®, a human-derived serum control material was used as quality control samples.

RESULTS

The coefficient of variations for both intra- and inter-day precisions were consistently <15% for all elements. The validated method was later tested on 30 human serum samples to evaluate its applicability.

CONCLUSION

We have successfully developed and validated a precise and accurate analytical method for determining 25 trace elements requiring very low volume of human serum.

Integrative Metabolomic and Metallomic Analysis in a Case-Control Cohort With Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disease with a complex etiology. Several factors are known to contribute to the disease onset and its progression. However, the complete underlying mechanisms are still escaping our understanding. To evaluate possible correlations between metabolites and metallomic data, in this research, we combined a control study measured using two different platforms. For the different data sources, we applied a Block Sparse Partial Least Square Discriminant Analysis (Block-sPLS-DA) model that allows for proving their relation, which in turn uncovers alternative influencing factors that remain hidden otherwise. We found two groups of variables that trace a strong relationship between metallomic and metabolomic parameters for disease development. The results confirmed that the redox active metals iron (Fe) and copper (Cu) together with fatty acids are the major influencing factors for the PD. Additionally, the metabolic waste product p-cresol sulfate and the trace element nickel (Ni) showed up as potentially important factors in PD. In summary, the data integration of different types of measurements emphasized the results of both stand-alone measurements providing a new comprehensive set of information and interactions, on PD disease, between different variables sources.

Elemental fingerprint: Reassessment of a cerebrospinal fluid biomarker for Parkinson's disease

The aim of the study was to validate a predictive biomarker machine learning model for the classification of Parkinson's disease (PD) and age-matched controls (AMC), based on bioelement abundance in the cerebrospinal fluid (CSF). For this multicentric trial, participants were enrolled from four different centers. CSF was collected according to standardized protocols. For bioelement determination, CSF samples were subjected to inductively coupled plasma mass spectrometry. A predefined Support Vector Machine (SVM) model, trained on a previous discovery cohort was applied for differentiation, based on the levels of six different bioelements. 82 PD patients, 68 age-matched controls and 7 additional Normal Pressure Hydrocephalus (NPH) patients were included to validate a predefined SVM model. Six differentiating elements (As, Fe, Mg, Ni, Se, Sr) were quantified. Based on their levels, SVM was successfully applied to a new local cohort (AUROC 0.76, Sensitivity 0.80, Specificity 0.83), without taking any additional features into account. The same model did not discriminate PD and AMCs / NPH from three external cohorts, likely due to center effects. However, discrimination was possible in cohorts with a full elemental data set, now using center-specific discovery cohorts and a cross validated approach (AUROC 0.78 and 0.88, respectively). Pooled PD CSF iron levels showed a clear correlation with disease duration (p = .0001). In summary, bioelemental CSF patterns, obtained by mass spectrometry and integrated into a predictive model yield the potential to facilitate the differentiation of PD and AMC. Center-specific biases interfere with application in external cohorts. This must be carefully addressed using center-defined, local reference values and models.

Targeting the microglial NLRP3 inflammasome and its role in Parkinson's disease

Excessive activation of microglia and subsequent release of proinflammatory cytokines play a crucial role in neuroinflammation and neurodegeneration in Parkinson's disease (PD). Components of the nucleotide-binding oligomerization domain and leucine-rich-repeat- and pyrin-domain-containing 3 inflammasome complex, leucine-rich-repeat- and pyrin-domain-containing 3, caspase-1, and apoptosis-associated speck-like protein containing a CARD, are highly expressed in activated microglia in PD patient brains. Findings suggest that neurotoxins, aggregation of α-synuclein, mitochondrial reactive oxygen species, and disrupted mitophagy are the key regulators of microglial leucine-rich-repeat- and pyrin-domain-containing 3 inflammasome activation and release of interleukin-1β and interleukin-18 caspase-1-mediated pyroptotic cell death in the substantia nigra of the brain. Although this evidence suggests the leucine-rich-repeat- and pyrin-domain-containing 3 inflammasome may be a potential drug target for treatment of PD, the exact mechanism of how the microglia sense these stimuli and initiate leucine-rich-repeat- and pyrin-domain-containing 3 inflammasome signaling is unknown. Here, the molecular mechanism and regulation of microglial leucine-rich-repeat- and pyrin-domain-containing 3 inflammasome activation and its role in the pathogenesis of PD are discussed. Moreover, the potential of both endogenous and synthetic leucine-rich-repeat- and pyrin-domain-containing 3 inflammasome modulators, long noncoding RNA, microRNA to develop novel therapeutics to treat PD is presented. Overall, we recommend that the microglial leucine-rich-repeat- and pyrin-domain-containing 3 inflammasome can be a potential target for PD treatment. © 2019 International Parkinson and Movement Disorder Society.

Iron Concentration Does Not Differ in Blood but Tends to Decrease in Cerebrospinal Fluid in Parkinson's Disease

Background

Iron accumulation in the substantia nigra in PD patients was acknowledged, but the studies on alteration of iron levels in blood and cerebrospinal fluids (CSF) reported inconsistent results.

Objective

To determinate the alterations of blood and CSF levels of iron in PD patients, a case-control study and a meta-analysis both in blood and CSF were conducted.

Methods

In the case-control study, 43 PD patients and 33 controls were recruited to test iron metabolism, 15 normal and 12 PD patients donated CSF. Levels in iron were quantified by inductively coupled atomic emission spectrometry. Iron metabolism was analyzed by routine blood tests. In the meta-analysis, a comprehensive literature search was performed on relevant studies published from Jan 1980 to Dec 2018 in PubMed, Web of Science and EMBASE databases. The pooled standard mean difference (SMD) with random effects model was selected to estimate the association between iron levels and PD.

Results

In the case-control study, the iron level in serum in the controls and PD patients were 110.00 ± 48.75 μg/dl and 107.21 ± 34.25 μg/dl, respectively, no significant difference was found between them (p = 0.850), with a small effect size (Cohen’s d: 0.12; 95% CI: 0.08–0.17). Ferritin level in PD patients was lower than controls (p = 0.014). The CSF levels of iron in control and the PD patients were 20.14 ± 3.35 ng/dl and 16.26 ± 4.82 ng/dl, respectively. CSF levels of iron were lower in PD compared with that of controls (p = 0.021), with a moderate effect size (Cohen’s d: 0.51; 95% CI: 0.43–0.65). In the meta-analysis, 22 eligible studies and a total of 3607 participants were identified. Blood levels of iron did not differ significant between PD patients and the controls [SMD (95% CI): −0.03 (−0.30, 0.24)], but CSF iron levels tended to be lower in PD patients compared with that in the controls [SMD (95% CI): −0.33 (−0.65, −0.00)].

Conclusion

Iron homeostasis may be disturbed in CSF, but not in the peripheral blood in PD.

Disturbance of trace element and gut microbiota profiles as indicators of autism spectrum disorder: A pilot study of Chinese children

Autism spectrum disorder (ASD) is a neuro-developmental disorder that is characterized by impairments of reciprocal social interaction and restricted stereotyped repetitive behavior. The goal of the present study was to investigate the trace element and gut microbiota profiles of Chinese autistic children and screen out potential metallic or microbial indicators of the disease. One hundred and thirty-six children (78 with ASD and 58 healthy controls) aged from 3 to 7 years were enrolled. The levels of lead, cadmium, arsenic, copper, zinc, iron, mercury, calcium and magnesium in hair samples from the children were analyzed. Fecal samples were also collected and the children's gut microbiota profiles were characterized by 16s rRNA sequencing. Concentrations of lead, arsenic, copper, zinc, mercury, calcium and magnesium were significantly higher in the ASD group than in the control group. Linear discriminant analysis effect size analysis indicated that the relative abundance of nine genera was increased in the autistic children. Redundancy analysis showed that arsenic and mercury were significantly associated with Parabacteroides and Oscillospira in the gut. A random forest model was trained with high accuracy (84.00%) and the metallic and microbial biomarkers of ASD were established. Our results indicate significant alterations in the trace element and gut microbiota profiles of Chinese children with ASD and reveal the potential pathogenesis of this disease in terms of metal metabolism and gut microecology.

Cerebrospinal fluid biomarker for Parkinson's disease: An overview

In Parkinson's disease (PD), there is a wide field of recent and ongoing search for useful biomarkers for early and differential diagnosis, disease monitoring or subtype characterization. Up to now, no biofluid biomarker has entered the daily clinical routine. Cerebrospinal fluid (CSF) is often used as a source for biomarker development in different neurological disorders because it reflects changes in central-nervous system homeostasis. This review article gives an overview about different biomarker approaches in PD, mainly focusing on CSF analyses. Current state and future perspectives regarding classical protein markers like alpha‑synuclein, but also different "omics" techniques are described. In conclusion, technical advancements in the field already yielded promising results, but further multicenter trials with well-defined cohorts, standardized protocols and integrated data analysis of different modalities are needed before successful translation into routine clinical application.

Promising Metabolite Profiles in the Plasma and CSF of Early Clinical Parkinson's Disease

Parkinson's disease (PD) shows high heterogeneity with regard to the underlying molecular pathogenesis involving multiple pathways and mechanisms. Diagnosis is still challenging and rests entirely on clinical features. Thus, there is an urgent need for robust diagnostic biofluid markers. Untargeted metabolomics allows establishing low-molecular compound biomarkers in a wide range of complex diseases by the measurement of various molecular classes in biofluids such as blood plasma, serum, and cerebrospinal fluid (CSF). Here, we applied untargeted high-resolution mass spectrometry to determine plasma and CSF metabolite profiles. We semiquantitatively determined small-molecule levels (≤1.5 kDa) in the plasma and CSF from early PD patients (disease duration 0-4 years; n = 80 and 40, respectively), and sex- and age-matched controls (n = 76 and 38, respectively). We performed statistical analyses utilizing partial least square and random forest analysis with a 70/30 training and testing split approach, leading to the identification of 20 promising plasma and 14 CSF metabolites. These metabolites differentiated the test set with an AUC of 0.8 (plasma) and 0.9 (CSF). Characteristics of the metabolites indicate perturbations in the glycerophospholipid, sphingolipid, and amino acid metabolism in PD, which underscores the high power of metabolomic approaches. Further studies will enable to develop a potential metabolite-based biomarker panel specific for PD.

Urinary metal and metalloid biomarker study of Henoch-Schonlein purpura nephritis using inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry

To obtain a better understanding as to whether concentration alterations of metals and metalloids in urine were related to Henoch-Schonlein purpura nephritis (HSPN), the profiles of as many as 29 elements in urine were compared among three groups, the Henoch-Schonlein purpura (HSP), HSPN and a healthy control group. To this end, a reliable method has been developed for the simultaneous quantification of multiple elements including Li, Be, B, Al, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Tl, Pb and Bi in urine using inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS). The process of sample pre-treatment used a direct 20-fold dilution method with centrifuged urine. The internal standard element used for quantification was ¹⁰³Rh, and 1,4-butanediol was chosen as a matrix matching reagent. The method detection limits of these 29 elements were in the range of 0.04-12ngmL^-1. Results of statistical analysis revealed that the concentrations of 15 elements and the element homeostasis were significantly different among these three groups. Our study provides a potential method for HSPN metal and metalloid biomarker discovery.

Elevated circulating magnesium levels in patients with Parkinson's disease: a meta-analysis

BACKGROUND

The association between circulating magnesium (Mg) and Parkinson's disease (PD) remains ambiguous and controversial. Thus, a meta-analysis was conducted to evaluate the circulating Mg levels in PD patients and to clarify whether high circulating Mg levels should be considered as a potential risk factor for PD.

METHODS

In this study, 17 case-control published studies were selected in our meta-analysis by searching the electronic databases of Web of Science, PubMed, and China National Knowledge Infrastructure (CNKI) before June 1, 2018. Overall, 848 PD cases and 784 healthy controls (HC), 1,023 PD cases and 911 HC, and 180 PD cases and 144 HC met the inclusion criteria for this study Mg levels in serum, peripheral blood, and cerebrospinal fluid (CSF), respectively. Standardized mean difference (SMD) in random-effects model and 95% CI were used to assess the correlation strength through the comparison of the two groups.

RESULTS

Meta-analysis showed that the serum Mg levels in PD cases were significantly higher than those in HC individuals (SMD =1.09, 95% CI =0.52, 1.66). Furthermore, this result was further confirmed by the combined analysis of serum and whole blood studies together (SMD =0.64, 95% CI =0.10, 1.19). In addition, the higher CSF Mg levels in patients of PD were observed in comparison with normal range (SMD =0.55, 95% CI =0.21, 0.88). However, this data did not further discuss and analyze because of the smaller sample size of CSF studies.

CONCLUSION

Our findings supported the notion that the increase of circulating Mg levels appears in the patients with PD.

Metallomics Applied to the Study of Neurodegenerative and Mental Diseases

Biochemical imbalances, provoked by aging or a secondary illness, might directly affect the brain, causing severe problems, such as loss of memory or alteration of behavior patterns. Brain disorders are usually classified as injuries (such as stroke, hematomas, and concussions), tumors, and neurodegenerative (such as Parkinson's and Alzheimer's diseases) and mental (such as depression, bipolar disorder, schizophrenia) diseases. As the pathophysiology of these illnesses is not completely established and multiple factors are involved, metallomics, a bioanalytical strategy that allows the detection of metal ions and metalloproteins in diverse biological matrices, is of extreme relevance in identifying which elements are affected by a disease and/or treatment. Thus, determining which element ions suffer disturbances in their homeostasis during the disease progress is relevant to understand the biochemical changes and propose new drug targets. In addition, it is well known that oxidative stress plays an important role in the development of pathological neurodegenerative and mental diseases, which may be caused by metal ion dyshomeostasis, so it is also important to understand endogenous antioxidant metalloprotein and metalloenzyme mechanisms in this regard. In this context, recent applications of metallomics in the study of neurodegenerative and mental disorders are discussed in this chapter, as well as future trends in this research area.

Association of circulating manganese levels with Parkinson's disease: A meta-analysis

Whether systemic manganese (Mn) dysfunctions in Parkinson's Disease (PD) is still under ongoing debate. The recent reported studies on the circulating Mn levels in PD showed inconsistent results. A meta-analysis study was conducted to evaluate the association of circulating Mn levels with PD, and to clarify whether Mn should be considered as a potential risk factor for PD. A systematic searching was performed based on PubMed, web of science, and China National Knowledge Infrastructure (CNKI). Finally, 22 studies were identified, involving 637 PD patients and 802 health controls (HC) individuals for serum Mn, 1258 PD patients and 1304 HC individuals for peripheral blood Mn, and 195 PD patients and 196 HC individuals for cerebrospinal fluid (CSF) Mn. Forest plots were adopted to represent the comparison of the groups by assessing standardized mean difference with random effects model. This meta-analysis revealed a significantly increased serum Mn levels in PD patients (SMD=0.78; 95% CI [0.32, 1.24]; P=0.001), and it was further confirmed when serum, plasma and whole blood studies were analyzed together (SMD=0.58; 95% CI [0.25, 0.91]; P=0.001). Instead, no significant differences of CSF Mn were observed between PD patients and HC individuals (SMD=-0.09; 95% CI [-0.47, 0.29]; P=0.644). These results supported the notion that elevated Mn level should be a potential risk factor for PD, although the high heterogeneity and methodological limitations recommended caution in the interpretations for the present findings.