Metabonomic and metallomic profiling in the amniotic fluid of malnourished pregnant rats

Utilizing Amniotic Fluid Metabolomics to Monitor Fetal Well-Being: A Narrative Review of the Literature

Fetal and perinatal periods are critical phases for long-term development. Early diagnosis of maternal complications is challenging due to the great complexity of these conditions. In recent years, amniotic fluid has risen in a prominent position in the latest efforts to describe and characterize prenatal development. Amniotic fluid may provide real-time information on fetal development and metabolism throughout pregnancy as substances from the placenta, fetal skin, lungs, gastric fluid, and urine are transferred between the mother and the fetus. Applying metabolomics to monitor fetal well-being, in such a context, could help in the understanding, diagnosis, and treatment of these conditions and is a promising area of research. This review shines a spotlight on recent amniotic fluid metabolomics studies and their methods as an interesting tool for the assessment of many conditions and the identification of biomarkers. Platforms in use, such as proton nuclear magnetic resonance (¹H NMR) and ultra-high-performance liquid chromatography (UHPLC), have different merits, and a combinatorial approach could be valuable. Metabolomics may also be used in the quest for habitual diet-induced metabolic signals in amniotic fluid. Finally, analysis of amniotic fluid can provide information on exposure to exogenous substances by detecting the exact levels of metabolites carried to the fetus and associated metabolic effects.

Effects of Quercetin on Acrylamide-Induced Variation of Serum Elements in Rats

Acrylamide (AA) is an organic chemical widely existing in the public diet, especially in foods with high-temperature fried and baked starchy and may have various adverse health effects on organisms. The purpose of this study was to investigate whether quercetin plays a protective role in AA-induced element variation in rats. Rats were randomly divided into the control group, AA-treated group [5 mg/kg body weight (bw)], two dosages of quercetin-treated groups (10 and 50 mg/kg·bw, respectively), and two dosages of quercetin plus AA-treated groups. After a 16-week treatment, the serum samples of rats were collected. Serum elements were analyzed by using inductively coupled plasma mass spectrometry (ICP-MS) combined with multivariate statistical analysis, and antioxidant indices, lipid peroxidation indicator, as well as inflammatory biomarkers, were also detected. The accuracy and precision of the method were verified, and all the validated data are within the satisfactory range. The results showed that the levels of vanadium (V), copper (Cu), zinc (Zn), selenium (Se), cobalt (Co), and magnesium (Mg) in serum were significantly lower (p < 0.01), while serum calcium (Ca) level was significantly higher (p < 0.01) in AA-treated group compared with the control group. When high-dose quercetin was administered to rats combined with AA, a significant recovered effect for the above elements levels was observed compared with the AA-treated group. This study suggests that quercetin (50 mg/kg·bw) exerts a regulatory and protective role in AA-induced variation of serum elements via reducing oxidative stress and inhibiting inflammation.

Metabolites in the association between early-life famine exposure and type 2 diabetes in adulthood over a 5-year follow-up period

INTRODUCTION

Exposure to malnutrition in early life has been found to significantly elevate type 2 diabetes risk in adulthood. However, the changes in metabolites resulting from malnutrition in early life have not been studied. The aim of this study was to identify metabolites with levels associated with type 2 diabetes resulting from exposure to China's Great Famine (1959-1962).

RESEARCH DESIGN AND METHODS

Participants were from SPECT-China 2014 and SPECT-China2 2019, two cross-sectional studies performed at the same site. In total, 2171 subjects participated in SPECT-China and SPECT-China2 simultaneously. The sample size of fetal-exposed (1959-1962) versus non-exposed (1963-1974) individuals was 82 vs 79 in 2014 and 97 vs 94 in 2019. Metabolomic profiling was performed between famine-exposed and non-exposed groups.

RESULTS

Among the different famine exposure groups, the fetal-exposed group (1959-1962) had the greatest incidence rate (12.5%), with an OR of 2.11 (95% CI 1.01 to 4.44), compared with the non-exposed group (1963-1974). Moreover, compared with those in the non-exposed group (1963-1974), four metabolites (indole-3-carbinol (I3C), phosphatidylcholine (PC) (22:6(4Z,7Z,10Z,13Z,16Z,19Z)/16:1(9Z)), pyrimidine, and PC(16:1(9Z)/22:5(4Z,7Z,10Z,13Z,16Z))) showed significantly lower relative intensities in the famine and diabetes groups both in 2014 and 2019. Pyrimidine significantly mediated the association of famine exposure with diabetes, and I3C marginally mediated this association.

CONCLUSIONS

Famine exposure in the fetal period could increase type 2 diabetes risk in adults, even those in their 60s. I3C and pyrimidine are potential mediators of the effects of famine exposure on diabetes development.

Integrated renal metabolomic and metallomic profiling revealed protective effect and metabolic mechanism of Gushudan on glucocorticoid-induced osteoporotic rat based on GC-MS and ICP-MS

Based on the traditional Chinese medicine theory, kidney is considered to govern the bones and dominate the store of essence ('jing' in Chinese). Gushudan (GSD) is a traditional Chinese medicine prescription for the treatment osteoporosis in the clinic and is beneficial for improving kidney function and strengthening bone in vivo. This study aims to reveal the renal metabolic profiling of glucocorticoid-induced osteoporosis (GIOP) rats and the potential preventive effect of GSD based on an integrative metabolomic and metallomic approach. Gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma mass spectrometry (ICP-MS) were combined for the investigation of renal metabolomic and metallomic profiling. In the metabolomic analysis, 17 potential biomarkers were found to be related to GIOP, such as glucose, malate, γ-aminobutyric acid and arachidonic acid. And seven metallic elements, including Zn, Mn, Se, Fe, Mo, As and Ba, were identified in rat kidney tissue in the metallomic analysis. The major metabolic pathways included aerobic glycolysis, and neurotransmitter amino acids metabolism. It was worth mentioning that the levels of trace metal elements (Zn, Mn, Se, Fe, As and Ba) significantly reduced in the model group, while the contents of Zn, Mn, Se, Fe and As were elevated after administration of GSD. Finally, a correlation metabolic regulatory network and the metabolic pathways associated with trace metal elements were further investigated to illuminate the role of potential biomarkers and trace metal elements in GIOP rats. These variations of potential biomarkers and trace metal elements suggested the existence of kidney damage and metabolic disorder in GIOP rats, which indicated a close relationship between bone and kidney in vivo. Moreover, the integrated renal metabolomic and metallomic profiling could be as an effective supplementary measure to the plasma and urine metabolomic research, and it was helpful to further understand the holistic formation process of osetoporosis and the potential preventive effects of GSD on GIOP rats.

Genetic regulatory subnetworks and key regulating genes in rat hippocampus perturbed by prenatal malnutrition: implications for major brain disorders

OBJECTIVE

Many population studies have shown that maternal prenatal nutrition deficiency may increase the risk of neurodevelopmental disorders in their offspring, but its potential transcriptomic effects on brain development are not clear. We aimed to investigate the transcriptional regulatory interactions between genes in particular pathways responding to the prenatal nutritional deficiency and to explore their effects on neurodevelopment and related disorders.

RESULTS

We identified three modules in rat hippocampus responding to maternal prenatal nutritional deficiency and found 15 key genes (Hmgn1, Ssbp1, LOC684988, Rpl23, Gga1, Rhobtb2, Dhcr24, Atg9a, Dlgap3, Grm5, Scn2b, Furin, Sh3kbp1, Ubqln1, and Unc13a) related to the rat hippocampus developmental dysregulation, of which Hmgn1, Rhobtb2 and Unc13a related to autism, and Dlgap3, Grm5, Furin and Ubqln1 are related to Alzheimer's disease, and schizophrenia. Transcriptional alterations of the hub genes were confirmed except for Atg9a. Additionally, through modeling miRNA-mRNA-transcription factor interactions for the hub genes, we confirmed a transcription factor, Cebpa, is essential to regulate the expression of Rhobtb2. We did not find singificent singals in the prefrontal cortex responding to maternal prenatal nutritional deficiency.

CONCLUSION

These findings demonstrated that these genes with the three modules in rat hippocampus involved in synaptic development, neuronal projection, cognitive function, and learning function are significantly enriched hippocampal CA1 pyramidal neurons and suggest that three genetic regulatory subnetworks and thirteen key regulating genes in rat hippocampus perturbed by a prenatal nutrition deficiency. These genes and related subnetworks may be prenatally involved in the etiologies of major brain disorders, including Alzheimer's disease, autism, and schizophrenia.

METHODS

We compared the transcriptomic differences in the hippocampus and prefrontal cortex between 10 rats with prenatal nutritional deficiency and 10 rats with prenatal normal chow feeding by differential analysis and co-expression network analysis. A network-driven integrative analysis with microRNAs and transcription factors was performed to define significant modules and hub genes responding to prenatal nutritional deficiency. Meanwhile, the module preservation test was conducted between the hippocampus and prefrontal cortex. Expression levels of the hub genes were further validated with a quantitative real-time polymerase chain reaction based on additional 40 pairs of rats.

Metabolomics of the amniotic fluid: Is it a feasible approach to evaluate the safety of Chinese medicine during pregnancy?

The use of Chinese medicines (CMs) during pregnancy has long been a major public health concern. Although CMs have been shown to be effective in treating infertility and preventing miscarriage, their use has been restricted, mainly because of limited knowledge of their potential toxicity. Accurate toxicology data are urgently required to assess whether these CMs are safe for maternal health and fetal development. Amniotic fluid (AF) contains carbohydrates, lipids and phospholipids, urea and proteins, all of which aid in the growth of the fetus and reflect the mother's health status as well. The changes in metabolomic patterns of AF are related to pathophysiological occurrences during the course of pregnancy. In this review, we provide a summary of the research performed in recent years on metabolomic AF samples, and use our previous study as an example to explore the feasibility of metabolomics of AF to evaluate the safety of CMs during pregnancy. We believe that metabolomics of AF play a far more important role than traditional morphology methods in the safety evaluation of CMs for pregnancy, with a higher sensitivity and correlation.

Effects of early-life malnutrition on neurodevelopment and neuropsychiatric disorders and the potential mechanisms

Lines of evidence have demonstrated that early-life malnutrition is highly correlated with neurodevelopment and adulthood neuropsychiatric disorders, while some findings are conflicting with each other. In addition, the biological mechanisms are less investigated. We systematically reviewed the evidence linking early-life nutrition status with neurodevelopment and clinical observations in human and animal models. We summarized the effects of special nutritious on neuropsychiatric disorders and explored the underlying potential mechanisms. The further understanding of the biological regulation of early-life nutritional status on neurodevelopment might shed light on precision nutrition at an integrative systems biology framework.

1H NMR-based metabolomics reveals the effect of maternal habitual dietary patterns on human amniotic fluid profile

Maternal diet may influence offspring’s health, even within well-nourished populations. Amniotic fluid (AF) provides a rational compartment for studies on fetal metabolism. Evidence in animal models indicates that maternal diet affects AF metabolic profile; however, data from human studies are scarce. Therefore, we have explored whether AF content may be influenced by maternal diet, using a validated food-frequency questionnaire and implementing NMR-based metabolomics. Sixty-five AF specimens, from women undergoing second-trimester amniocentesis for prenatal diagnosis, were analysed. Complementary, maternal serum and urine samples were profiled. Hierarchical cluster analysis identified 2 dietary patterns, cluster 1 (C1, n = 33) and cluster 2 (C2, n = 32). C1 was characterized by significantly higher percentages of energy derived from refined cereals, yellow cheese, red meat, poultry, and “ready-to-eat” foods, while C2 by higher (P < 0.05) whole cereals, vegetables, fruits, legumes, and nuts. ¹H NMR spectra allowed the identification of metabolites associated with these dietary patterns; glucose, alanine, tyrosine, valine, citrate, cis-acotinate, and formate were the key discriminatory metabolites elevated in C1 AF specimens. This is the first evidence to suggest that the composition of AF is influenced by maternal habitual dietary patterns. Our results highlight the need to broaden the knowledge on the importance of maternal nutrition during pregnancy.

Evaluation of a novel method for measurement of intracellular calcium ion concentration in fission yeast

The distribution of metal and metalloid species in each of the cell compartments is termed as "metallome". It is important to elucidate the molecular mechanism underlying the beneficial or toxic effects exerted by a given metal or metalloid on human health. Therefore, we developed a method to measure intracellular metal ion concentration (particularly, intracellular calcium ion) in fission yeast. We evaluated the effects of nitric acid (HNO₃), zymolyase, and westase treatment on cytolysis in fission yeast. Moreover, we evaluated the changes in the intracellular calcium ion concentration in fission yeast in response to treatment with/without micafungin. The fission yeast undergoes lysis when treated with 60% HNO₃, which is simpler and cheaper compared to the other treatments. Additionally, the intracellular calcium ion concentration in 60% HNO₃-treated fission yeast was determined by inductively coupled plasma atomic emission spectrometry. This study yields significant information pertaining to measurement of the intracellular calcium ion concentration in fission yeast, which is useful for elucidating the physiological or pathological functions of calcium ion in the biological systems. This study is the first step to obtain perspective view on the effect of the metallome in biological systems.

Hair chemical element contents and influence factors of reproductive-age women in the West Ujimqin Banner, Inner Mongolia, China

Women have an increased risk for chemical element deficiencies during reproductive age, particularly due to higher chemical element requirements and poor diets. Twenty-one chemical elements (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Se, Si, Sn, Sr, Ti, V and Zn) in hair samples, which were collected from 71 non-pregnant and 236 pregnant women living in the West Ujimqin Banner, central Inner Mongolia, China, were measured, and the environment, dietary habits and ethnic group influence factors associated with the biomarker were analyzed. The results indicated that the average values of the chemical element contents from hair were greatly different compared to those from other areas, especially the Al, Cd, Pb, Ca and Sr contents. There was no significant difference among the three ethnicities for any element except Mn and Ti in non-pregnant women. Compared to non-pregnant women, in the first trimester group, the levels of nine chemical elements (Ba, Cd, Cu, Pb, Se, Si, Sn and Ti) decreased, while the others increased, and the contents of all of the chemical elements decreased in the second trimester group, while in the third trimester, there was a slight increase. Three chemical elements (Cu, Mn and Zn) displayed a synergistic correlation between each other in the third trimester group, which may protect the placenta from some oxidant damage. The high levels of Cd and Pb in hair likely originate from house renovations and traffic pollution. This study provided basic and useful information on the levels of chemical elements in reproductive-age women, and the results of this study are helpful to control the contents and improve the health of pregnant and non-pregnant women.

Primary HCMV infection in pregnancy from classic data towards metabolomics: An exploratory analysis

BACKGROUND

Human cytomegalovirus (HCMV) is one of the most frequent risk of viral infections during pregnancy. The aim of this study was to evaluate the metabolic profile in amniotic fluid (AF) samples obtained from HCMV-infected, and uninfected fetuses in order to elucidate changes in metabolic pathways during congenital HCMV infection and to recognize new potential diagnostic and/or prognostic biomarkers.

METHODS

A retrospective cohort study was conducted on 63 pregnant women: 20 contracted primary HCMV infection during pregnancy and, subsequently, transmitted the virus to the fetus (transmitters); 20 contracted the infection without transmitting the virus to the fetus (non-transmitters); 23 who underwent amniocentesis for cytogenetic-based diagnosis were considered controls. Metabolomics analysis was performed by using the hyphenated technique Gas chromatography-mass spectrometry (GC-MS) followed by a multivariate statistical approach. Four PLS-DA models were generated: controls vs. transmitters; controls vs. non-transmitters; transmitters vs. non-transmitters; and asymptomatic infected vs. symptomatic infected newborns. Subsequently, these models were exploited for network mapping.

RESULTS

Compared with controls, HCMV transmitters showed significantly increased levels in glutamine, glycine, serine, pyruvic acid, threonine, threonic acid, and cystine; conversely, unknown U1715 and U1804, glutamic acid, U1437, fructose, sugar-like A203003 and A203005, and tyrosine levels were found decreased. In non-transmitters, glutamine, serine, glycine, threonic acid, threonine, 1-monostearin, urea, and cystine were found increased, while sorbitol, unknown U1804, sugar-like A203003, U1751, xylitol, leucine and fructose were decreased. The comparison between transmitters and non-transmitters did not produce a statistically significant model. Unlike controls' profile, a common feature of HCMV infected subjects (transmitters and non-transmitters) was the activation of glutamine-glutamate and pyrimidine metabolic pathways. In addition, a clusterization for asymptomatic vs. symptomatic outcome was also observed due to alteration of fatty acids biosynthesis.

CONCLUSIONS

Metabolomics approach could highlight the significant modification of maternal and placental status during HCMV infection for both transmitter and non-transmitter subjects. A further separation was observed for asymptomatic vs. symptomatic HCMV congenital infections model. Therefore, metabolomics may be a promising tool to improve the accuracy of an early diagnosis, and the management of HCMV pregnancy-related infections.

The choice of amniotic fluid in metabolomics for the monitoring of fetus health

Amniotic fluid (AF) is a biological fluid in which metabolite transport is regulated by the placenta, the permeable skin, fetal lung egress and gastric fluid. During pregnancy, the composition of AF changes from similar to the interstitial fluid of the mother, to a more complex system, influenced by the fetus's urine. Since AF reflects the mother's and the fetus's health status at the same time, it may be an important diagnostic tool for a wider spectrum of clinical conditions. Indeed, the metabolic characterization of AF in relation to pathological occurrences may lead to the discovery of new biomarkers for a better clinical practice. For this reason, metabolomics may be the most suitable strategy for this task. In this review, research works on metabolomic AF analysis are discussed according to the morbidity of interest, being preterm birth/labor, gestational age and diabetes and fetal malformations, along with a number of other important studies.

Prenatal nutritional deficiency reprogrammed postnatal gene expression in mammal brains: implications for schizophrenia

BACKGROUND

Epidemiological studies have identified prenatal exposure to famine as a risk factor for schizophrenia, and animal models of prenatal malnutrition display structural and functional brain abnormalities implicated in schizophrenia.

METHODS

The offspring of the RLP50 rat, a recently developed animal model of prenatal famine malnutrition exposure, was used to investigate the changes of gene expression and epigenetic modifications in the brain regions. Microarray gene expression analysis was carried out in the prefrontal cortex and the hippocampus from 8 RLP50 offspring rats and 8 controls. MBD-seq was used to test the changes in DNA methylation in hippocampus depending on prenatal malnutrition exposure.

RESULTS

In the prefrontal cortex, offspring of RLP50 exhibit differences in neurotransmitters and olfactory-associated gene expression. In the hippocampus, the differentially-expressed genes are related to synaptic function and transcription regulation. DNA methylome profiling of the hippocampus also shows widespread but systematic epigenetic changes; in most cases (87%) this involves hypermethylation. Remarkably, genes encoded for the plasma membrane are significantly enriched for changes in both gene expression and DNA methylome profiling screens (p = 2.37×10(-9) and 5.36×10(-9), respectively). Interestingly, Mecp2 and Slc2a1, two genes associated with cognitive impairment, show significant down-regulation, and Slc2a1 is hypermethylated in the hippocampus of the RLP50 offspring.

CONCLUSIONS

Collectively, our results indicate that prenatal exposure to malnutrition leads to the reprogramming of postnatal brain gene expression and that the epigenetic modifications contribute to the reprogramming. The process may impair learning and memory ability and result in higher susceptibility to schizophrenia.

DNA methylation profiling in the thalamus and hippocampus of postnatal malnourished mice, including effects related to long-term potentiation

Background

DNA methylation has been viewed as the most highly characterized epigenetic mark for genome regulation and development. Postnatal brains appear to exhibit stimulus-induced methylation changes because of factors such as environment, lifestyle, and diet (nutrition). The purpose of this study was to examine how extensively the brain DNA methylome is regulated by nutrition in early life.

Results

By quantifying the total amount of 5-methylcytosine (5mC) in the thalamus and the hippocampus of postnatal malnourished mice and normal mice, we found the two regions showed differences in global DNA methylation status. The methylation level in the thalamus was much higher than that in the hippocampus. Then, we used a next-generation sequencing (NGS)-based method (MSCC) to detect the whole genome methylation of the two regions in malnourished mice and normal mice. Notably, we found that in the thalamus, 500 discriminable variations existed and that approximately 60% were related to neuronal development or psychiatric diseases. Pathway analyses of the corresponding genes highlighted changes for 9 genes related to long-term potentiation (5.3-fold enrichment, P = 0.033).

Conclusions

Our findings may help to indicate the genome-wide DNA methylation status of different brain regions and the effects of malnutrition on brain DNA methylation. The results also indicate that postnatal malnutrition may increase the risk of psychiatric disorders.

Hippocampal metabolomics reveals 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity associated with ageing in Sprague-Dawley rats

Metabolomics, the exponentially developing technique, could provide a systemic mapping in toxicology by directly measuring small molecular metabolites. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was found to be neurotoxic in mammalian animals. In this study, we employed liquid chromatography/quadrupole time-of-flight mass spectrometry for non-targeted analysis of metabolic profiling in hippocampal sample sets of the rats exposed to TCDD. Hippocampal metabolome from different ages of the healthy rats (4-week, 12-week and 20-week) was also deciphered. The relationship between the two tested cases was unlocked to delineate TCDD toxicity associated with ageing. Tandem mass spectrometry fragmentation in conjunction with metabolic database searching and compared to authentic standards was utilized for metabolite identification. As a consequence, the reduced levels of phenylalanine and leucine/isoleucine as well as the up-regulation of inosine and hypoxanthine were highlighted for understanding of TCDD toxicity related to age in rats and the trajectory was depicted by principal components analysis.

Urinary metabonomics study in a rat model in response to protein-energy malnutrition by using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry

Systematic studies were performed on the biological perturbations in metabolic phenotype responding to protein-energy malnutrition through global metabolic profiling analysis, in combination with pattern recognition. The malnutrition rat model was established through five weeks of strict diet restriction, and the metabonome data obtained from gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) were integrated to approximate the comprehensive metabolic signature. Principal component analysis and orthogonal projection to latent structure analysis were used for the classification of metabolic phenotypes and discovery of differentiating metabolites. The perturbations in the urine profiles of malnourished rats were marked by higher levels of creatine, threitol, pyroglutamic acid, gluconic acid and kynurenic acid, as well as decreased levels of succinic acid, cis-aconitic acid, citric acid, isocitric acid, threonic acid, trimethylglycine, N-methylnicotinic acid and uric acid. The alterations in these metabolites were associated with perturbations in energy metabolism, carbohydrate, amino acid, and fatty acid metabolism, purine metabolism, cofactor and vitamin metabolism, in response to protein and energy malnutrition. Our findings show the integration of GC-MS and LC-MS techniques for untargeted metabolic profiling analysis was promising for nutriology.

An optimized procedure for metabonomic analysis of rat liver tissue using gas chromatography/time-of-flight mass spectrometry

In this paper, we present a tissue metabonomic method with an optimized extraction procedure followed by instrumental analysis with gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) and spectral data analysis with multivariate statistics. Metabolite extractions were carried out using three solvents: chloroform, methanol, and water, with design of experiment (DOE) theory and multivariate statistical analysis. A two-step metabolite extraction procedure was optimized using a mixed solvent of chloroform-methanol-water (1:2:1, v/v/v) and then followed by methanol alone. This approach was subsequently validated using standard compounds and liver tissues. Calibration curves were obtained in the range of 0.50-125.0mug/mL for standards and 0.02-0.25g/mL acceptable for liver tissue samples. For most of the metabolites investigated, relative standard deviations (RSD) were below 10% within a day (reproducibility) and below 15% within a week (stability). Rat liver tissues of carbon tetrachloride-induced acute liver injury models (n=10) and healthy control rats (n=10) were analyzed which demonstrated the applicability of the developed procedure for the tissue metabonomic study.

Mass-spectrometry-based metabolomics: limitations and recommendations for future progress with particular focus on nutrition research

Mass spectrometry (MS) techniques, because of their sensitivity and selectivity, have become methods of choice to characterize the human metabolome and MS-based metabolomics is increasingly used to characterize the complex metabolic effects of nutrients or foods. However progress is still hampered by many unsolved problems and most notably the lack of well established and standardized methods or procedures, and the difficulties still met in the identification of the metabolites influenced by a given nutritional intervention. The purpose of this paper is to review the main obstacles limiting progress and to make recommendations to overcome them. Propositions are made to improve the mode of collection and preparation of biological samples, the coverage and quality of mass spectrometry analyses, the extraction and exploitation of the raw data, the identification of the metabolites and the biological interpretation of the results.

Trace element profiling using inductively coupled plasma mass spectrometry and its application in an osteoarthritis study

In this study, a novel method of quantitatively measuring serum trace elements using inductively coupled plasma mass spectrometry (ICP-MS) coupled with multivariate statistical analysis was developed and applied successfully to the study of osteoarthritis (OA). This technology provides potential advantages over conventional targeted elemental analysis in that it achieves high throughput measurement, small sample volume, and simple operational procedure. Such an unbiased method is particularly suitable for large scale discovery research on trace element based biomarkers. The method optimization and validation study involved accuracy and perturbation testing which focused on estimating the ability of the method to resist interferences in ICP-MS analysis, particularly those of mass <82 amu, in the serum sample. The developed method was successfully applied to the study of serum samples from OA patients. As a result, the serum trace element profiles of OA patients were distinctively separated from those of the healthy controls (HC) using an Orthogonal Projections to Latent Structures Discriminant Analysis (OPLSDA) model. Additionally, significantly differential elements correlated with OA, such as Li and Sn, were identified as potential elemental-based biomarkers.