Determination of major and trace element variability in healthy human urine by ICP-QMS and specific gravity normalisation

Associations between individual and mixed urinary metal exposure and dyslipidemia among Chinese adults: Data from the China Multi-Ethnic Cohort Study

The prevalence of dyslipidemia is increasing, and it has become a significant global public health concern. Some studies have demonstrated contradictory relationships between urinary metals and dyslipidemia, and the combined effects of mixed urinary metal exposure on dyslipidemia remain ambiguous. In this study, we examined how individual and combined urinary metal exposure are associated with the occurrence of dyslipidemia. According to the data from the 2018-2019 baseline survey database of the China Multi-Ethnic Cohort (CMEC) Study, a population of 9348 individuals was studied. Inductively coupled plasmamass spectrometry (ICP-MS) was used to measure 21 urinary metal concentrations in the collected adult urinary samples. The associations between urinary metals and dyslipidemia were analyzed by logistic regression, weighted quantile sum regression (WQS), and quantile-based g-computation (qgcomp), controlled for potential confounders to examine single and combined effects. Dyslipidemia was detected in 3231 individuals, which represented approximately 34.6 % of the total population. According to the single-exposure model, Al and Na were inversely associated with the risk of dyslipidemia (OR = 0.95, 95 % CI: 0.93, 0.98; OR = 0.89, 95 % CI: 0.83, 0.95, respectively), whereas Zn, Ca, and P were positively associated (OR = 1.69, 95 % CI: 1.42, 2.01; OR = 1.12, 95 % CI: 1.06, 1.18; OR = 1.21, 95 % CI: 1.09, 1.34, respectively). Moreover, Zn and P were significantly positively associated even after adjusting for these metals, whereas Al and Cr were negatively associated with the risk of dyslipidemia. The results of the WQS and qgcomp analyses showed that urinary metal mixtures were positively associated with the risk of dyslipidemia (OR = 1.26, 95 % CI: 1.15, 1.38; OR = 1.09, 95 % CI: 1.01, 1.19). This positive association was primarily driven by Zn, P, and Ca. In the sensitivity analyses with collinearity diagnosis, interaction, and stratified analysis, the results remained, confirming the reliability of the study findings. In this study, the individual and combined effects of urinary Zn, P, and Ca on dyslipidemia were determined, which provided novel insights into the link between exposure to metals and dyslipidemia.

Association between Sperm Mitochondrial DNA Copy Number and Concentrations of Urinary Cadmium and Selenium

Elevated sperm mitochondrial DNA copy number (mtDNAcn) is associated with damage to sperm and poorer measures of semen quality. Exposure to cadmium (Cd) can increase oxidative stress and damage sperm mitochondria. The adverse effects of Cd can potentially be reduced by sufficient selenium (Se). The objective of this study was to examine the associations between sperm mtDNAcn and urinary concentrations of Cd and Se, as well as the Cd/Se molar ratio. Participants were recruited from patients who sought infertility treatment at two hospitals in Japan. Urine and semen specimens and self-administered questionnaires were collected on the day of recruitment. Sperm mtDNAcn was measured in extracted sperm DNA by multiplex real-time qPCR. Urinary Cd and Se concentrations were measured using inductively coupled plasma mass spectrometry, and their molar weights were calculated to obtain the Cd/Se molar ratio. Linear regression was used to estimate associations after adjusting for age, body mass index, smoking, drinking, exercise, varicocele, and hospital of recruitment. Sperm mtDNAcn showed statistically insignificant associations with creatinine-adjusted concentrations of urinary Cd (β = 0.13, 95% CI -0.18, 0.44) and Se (β = -0.09, 95% CI -0.54, 0.35), and Cd/Se molar ratio (β = 0.12, 95% CI -0.13, 0.37). The current study found no evidence of an association between mtDNAcn and urinary concentrations of Cd or Se, or the Cd/Se molar ratio.

Analysis of urinary potassium isotopes and association with pancreatic health: healthy, diabetic and cancerous states

Background

More than 700 million people worldwide suffer from diseases of the pancreas, such as diabetes, pancreatitis and pancreatic cancer. Often dysregulation of potassium (K+) channels, co-transporters and pumps can promote development and progression of many types of these diseases. The role of K+ transport system in pancreatic cell homeostasis and disease development remains largely unexplored. Potassium isotope analysis (δ41K), however, might have the potential to detect minute changes in metabolic processes relevant for pancreatic diseases.

Methods

We assessed urinary K isotope composition in a case-control study by measuring K concentrations and δ41K in spot urines collected from patients diagnosed with pancreatic cancer (n=18), other pancreas-related diseases (n=14) and compared those data to healthy controls (n=16).

Results

Our results show that urinary K+ levels for patients with diseased pancreas (benign and pancreatic cancer) are significantly lower than the healthy controls. For δ41K, the values tend to be higher for individuals with pancreatic cancer (mean δ41K = -0.58 ± 0.33‰) than for healthy individuals (mean δ41K = -0.78 ± 0.19‰) but the difference is not significant (p=0.08). For diabetics, urinary K+ levels are significantly lower (p=0.03) and δ41K is significantly higher (p=0.009) than for the healthy controls. These results suggest that urinary K+ levels and K isotopes can help identify K disturbances related to diabetes, an associated factors of all-cause mortality for diabetics.

Conclusion

Although the K isotope results should be considered exploratory and hypothesis-generating and future studies should focus on larger sample size and δ41K analysis of other K-disrupting diseases (e.g., chronic kidney disease), our data hold great promise for K isotopes as disease marker.

Rapid Near-Patient Impedimetric Sensing Platform for Prostate Cancer Diagnosis

With the global escalation of concerns surrounding prostate cancer (PCa) diagnosis, reliance on the serologic prostate-specific antigen (PSA) test remains the primary approach. However, the imperative for early PCa diagnosis necessitates more effective, accurate, and rapid diagnostic point-of-care (POC) devices to enhance the result reliability and minimize disease-related complications. Among POC approaches, electrochemical biosensors, known for their amenability and miniaturization capabilities, have emerged as promising candidates. In this study, we developed an impedimetric sensing platform to detect urinary zinc (UZn) in both artificial and clinical urine samples. Our approach lies in integrating label-free impedimetric sensing and the introduction of porosity through surface modification techniques. Leveraging a cellulose acetate/reduced graphene oxide composite, our sensor's recognition layer is engineered to exhibit enhanced porosity, critical for improving the sensitivity, capture, and interaction with UZn. The sensitivity is further amplified by incorporating zincon as an external dopant, establishing highly effective recognition sites. Our sensor demonstrates a limit of detection of 7.33 ng/mL in the 0.1-1000 ng/mL dynamic range, which aligns with the reference benchmark samples from clinical biochemistry. Our sensor results are comparable with the results of inductively coupled plasma mass spectrometry (ICP-MS) where a notable correlation of 0.991 is achieved. To validate our sensor in a real-life scenario, tests were performed on human urine samples from patients being investigated for prostate cancer. Testing clinical urine samples using our sensing platform and ICP-MS produced highly comparable results. A linear correlation with R2 = 0.964 with no significant difference between two groups (p-value = 0.936) was found, thus confirming the reliability of our sensing platform.

Could Urinary Copper/Zinc Ratio Be a Newer Tool to Replace 24-Hour Urinary Copper Excretion for Diagnosing Wilson Disease in Children?

Purpose

Although the 24-hours urinary copper excretion is useful for the diagnosis of Wilson disease (WD), there are practical difficulties in the accurate and timed collection of urine samples. The purpose of this study was to verify if the spot morning urinary Copper/ Zinc (Cu/Zn) ratio could be used as a replacement parameter of 24-hours urinary copper excretion in the diagnosis of WD.

Methods

A cross-sectional study was conducted at the Department of Pediatric Gastroenterology and Nutrition, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, from June 2019 to May 2021 on 67 children over three years of age who presented with liver disease. Twenty-seven children who fulfilled the inclusion criteria for WD were categorized into the test group, and the remaining forty children were considered to have non-Wilsonian liver disease and were categorized into the control group. Along with other laboratory investigations, spot morning urinary samples were estimated for the urinary Cu/Zn ratio in all patients and were compared to the 24-hour urinary copper excretion. The diagnostic value of the Cu/Zn ratio was then analyzed.

Results

Correlation of spot morning urinary Cu/Zn ratio with 24-hours urinary copper excretion was found to be significant (r=0.60). The area under ROC curve with 95% confidence interval of morning urinary Cu/Zn ratio measured using 24-hours urine sample was 0.84 (standard error, 0.05; p<0.001).

Conclusion

Spot morning urinary Cu/Zn ratio seems to be a promising parameter for the replacement of 24-hours urinary copper excretion in the diagnosis of WD.

Association of Urinary Zinc Concentrations with Dyslipidemia and Its Subtypes: Baseline Data from the Chinese Multi-Ethnic Cohort (CMEC) Study

This study elucidates the association between urinary zinc concentration and the risk of developing dyslipidemia and its subtypes in China's ethnic minority residents. Based on the baseline survey data of the Chinese Multi-Ethnic Cohort (CMEC) study, 10,620 subjects were included in the study. Logistic regression analysis evaluated the relationship between urinary zinc concentration and dyslipidemia and its subtypes. After adjustment, compared with urinary zinc concentration quartile 1 (Q1), the odds ratios (ORs) and 95% confidence intervals (95% CIs) of dyslipidemia participants in the quartile 2 (Q2), quartile 3 (Q3), and quartile 4 (Q4) groups were 1.091 (0.963, 1.237), 1.151 (1.051, 1.304), and 1.393 (1.230, 1.579), respectively (P for trend < 0.001). While that of hypertriglyceridemia participants in the Q2, Q3, and Q4 groups were 1.130 (0.979, 1.306), 1.283 (1.113, 1.480), and 1.483 (1.287, 1.709), respectively (P for trend < 0.001). Lastly, the ORs and 95% CIs of hyperbetalipoproteinemia participants in the Q2, Q3, and Q4 groups were 1.166 (0.945, 1.439), 1.238 (1.007, 1.522), and 1.381 (1.126, 1.695), respectively (P for trend < 0.002). This study found that urinary zinc concentrations were not associated with hypercholesterolemia and hypoalphalipoproteinemia. The dose-response relationship was non-linear between urinary zinc concentration and dyslipidemia, hypertriglyceridemia and hyperbetalipoproteinemia (P for trend < 0.001). In the stratified analysis, urinary zinc levels were positively associated with the risk of dyslipidemia, hypertriglyceridemia, and hyperbetalipoproteinemia in male, ≥ 60 years old, Miao nationality, hypertension, diabetes, and BMI ≥ 24.0 kg/m² subgroups. Our study provides some possible evidence that elevated urinary zinc concentrations are associated with an increased risk of dyslipidemia, hypertriglyceridemia, hyperbetalipoproteinemia.

Time course of pulmonary inflammation and trace element biodistribution during and after sub-acute inhalation exposure to copper oxide nanoparticles in a murine model

Background

It has been shown that copper oxide nanoparticles (CuO NPs) induce pulmonary toxicity after acute or sub-acute inhalation exposures. However, little is known about the biodistribution and elimination kinetics of inhaled CuO NPs from the respiratory tract. The purposes of this study were to observe the kinetics of pulmonary inflammation during and after CuO NP sub-acute inhalation exposure and to investigate copper (Cu) biodistribution and clearance rate from the exposure site and homeostasis of selected trace elements in secondary organs of BALB/c mice.

Results

Sub-acute inhalation exposure to CuO NPs led to pulmonary inflammation represented by increases in lactate dehydrogenase, total cell counts, neutrophils, macrophages, inflammatory cytokines, iron levels in bronchoalveolar lavage (BAL) fluid, and lung weight changes. Dosimetry analysis in lung tissues and BAL fluid showed Cu concentration increased steadily during exposure and gradually declined after exposure. Cu elimination from the lung showed first-order kinetics with a half-life of 6.5 days. Total Cu levels were significantly increased in whole blood and heart indicating that inhaled Cu could be translocated into the bloodstream and heart tissue, and potentially have adverse effects on the kidneys and spleen as there were significant changes in the weights of these organs; increase in the kidneys and decrease in the spleen. Furthermore, concentrations of selenium in kidneys and iron in spleen were decreased, pointing to disruption of trace element homeostasis.

Conclusions

Sub-acute inhalation exposure of CuO NPs induced pulmonary inflammation, which was correlated to Cu concentrations in the lungs and started to resolve once exposure ended. Dosimetry analysis showed that Cu in the lungs was translocated into the bloodstream and heart tissue. Secondary organs affected by CuO NPs exposure were kidneys and spleen as they showed the disruption of trace element homeostasis and organ weight changes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00480-z.

Analysis of Threshold Effect of Urinary Heavy Metal Elements on the High Prevalence of Nephrolithiasis in Men

Exposure to heavy metals in the environment exerts serious effects on kidney health. However, the effects of joint exposure on the kidneys have been rarely studied, particularly in non-occupational exposure high-risk populations. This study provided a reference threshold range of heavy metals in urine and explored the effect of joint exposure on nephrolithiasis in men. The data were obtained from the China Multi-Ethnic Cohort database, and 1502 men were included in the study. A two-piece-wise regression model was used to assess the dose-response relationship between heavy metal exposure and nephrolithiasis. The least absolute shrinkage and selection operator regression model was used to calculate the score of joint exposure to heavy metals. The threshold effect analysis revealed a linear relationship between the concentration of arsenic (As) in the urine and the prevalence of nephrolithiasis, whereas a nonlinear relationship was observed with cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb). In addition, As, Cd, Cr, Hg, and Pb may significantly affect the joint exposure effect. Moreover, the final risk of nephrolithiasis increased by 123% (P for trend < 0.001). This study found a threshold relationship between heavy metals (Cd, Cr, Hg, Pb) in male urine and the occurrence of nephrolithiasis. Joint exposure to heavy metals in urine caused a high-risk effect on nephrolithiasis. The study provided a reference threshold value of related studies and indicated that environmental pollution caused by heavy metals should be reduced.

Versatile Integration of Liquid-Phase Microextraction and Fluorescent Aptamer Beacons: A Synergistic Effect for Bioanalysis

Fluorescent aptamer beacons (FABs) are a major category of biosensors widely used in environmental analysis. However, due to their low compatibility, it is difficult to use the common FABs for biological samples. To overcome this challenge, construction of FABs with complex structures to adapt the nature of biological samples is currently in progress in this field. Unlike previous works, we moved our range of vision from the FAB itself to the biological sample. Inspired by this idea, in this work, flat membrane-based liquid-phase microextraction (FM-LPME) with sufficient sample cleanup and preconcentration capacities was integrated with FABs. With the merits of both FM-LPME and FABs, the integrated LPME-FAB system displayed a clear synergistic enhancement for target analysis. Specifically, LPME in the LPME-FAB system provided purified and enriched Hg²⁺ for the FAB recognition, while the FAB recognition event promoted the extraction efficiency of LPME. Due to superior performances, the LPME-FAB system achieved highly sensitive analysis of Hg²⁺ in urine samples with a detection limit of 27 nM and accuracies in the range of 98-113%. To the best of our knowledge, this is the first time that an integrated LPME-FAB system was constructed for target analysis in biological samples. We believe that this study will provide a new insight into the next generation of biosensors, where the integration of sample preparation with detection probes is as important as the design of complex probes in the field of bioanalysis.

Zinc stable isotopes in urine as diagnostic for cancer of secretory organs

Breast, prostate, and pancreatic cancers alter the zinc (Zn) metabolism. Combined analyses of urinary Zn concentrations [Zn] and Zn stable isotope compositions (δ66Zn) may provide a non-invasive approach for tracing malignancy-induced Zn dyshomeostasis. In this study, we measured [Zn] and δ66Zn in urine from prostate (n = 22), breast (n = 16), and from women with benign breast disease (n = 14) and compared those with age-matched healthy controls (22-49 years or 50+ years) and published data for pancreatic cancer (n = 17). Our results show that cancer-induced changes are reflected in higher urinary [Zn] and lower urinary δ66Zn for pancreatic and prostate cancer and benign breast disease when compared with healthy controls. For prostate cancer, the progression of low [Zn] and high δ66Zn for patients of low-risk disease toward high [Zn] and low δ66Zn for the higher risk patients demonstrates that [Zn] and δ66Zn in urine could serve as a reliable prognostic tool. Urinary excretion of isotopically light Zn by patients with prostatic and pancreatic cancer is probably the result of increased reactive oxygen species in cancerous cells, which limits the scavenging of hydroxyl radicals and thus facilitates the oxidation of metalloproteins with sulfur-rich ligands. Urine from breast cancer patients shows undistinguishable δ66Zn to healthy controls, implying that the expression of metalloproteins with sulfur-rich ligands is stronger in breast cancer tissues. In conclusion, urinary δ66Zn may provide a non-invasive diagnostic tool for pancreatic cancer and support disease prognosis for prostate cancer. These findings should translate to comprehensive transverse and longitudinal cohort studies in future.

Precise determination of the molybdenum isotopic composition of urine by multiple collector inductively coupled plasma mass spectrometry

RATIONALE

Molybdenum (Mo) is predominantly expelled from the human body in urine. Consequently, urinary variability in the concentration and isotopic composition of Mo may encode valuable clinical information. To access this information, however, it is first necessary to develop and demonstrate a rapid, accurate and precise methodology capable of concentrating Mo from urine for isotope analysis.

METHODS

The utility of N-benzoyl-N-phenylhydroxylamine (BPHA) to effectively separate and purify Mo from urine samples without the need for acid digestion was tested. Following this approach, applying a double-spike mass bias correction, we determined the Mo isotopic compositions of a set of urine samples by multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS).

RESULTS

Based on replicate analyses of an in-house urine standard, this approach demonstrates an external precision on δ^98/95 Mo values of better than 0.08‰ (2SD, n = 15). Application to a sample set collected from healthy individuals in Guangzhou, China, provides the first suite of δ^98/95 Mo measurements from urine samples. Samples from the female participants show δ^98/95 Mo (‰) values (1.31 ± 0.19‰, Ave ± 2SD, n = 14) that are consistently lower than those from the male participants (1.55 ± 0.16‰, Ave ± 2SD, n = 17).

CONCLUSIONS

The employed methodology is suitable for rapid, low-blank and high-throughput Mo isotope analysis of urine samples. Although resolvable δ^98/95 Mo variability is seen in this preliminary dataset, the mechanism driving this variability is unknown. High-precision Mo isotopic analysis might be added to the urinalysis tool-kit, with the potential to provide valuable clinical information in the future.

Reference intervals of spot urine copper excretion in preschool children and potential application in pre-symptomatic screening of Wilson disease

The objectives were to determine the reference intervals of spot urine copper excretion indexes in pre-school children and to evaluate their utility in screening for Wilson disease (WD). With spot urine collected from a control sample of preschool children (aged 3-7 years, n=153), the reference intervals of spot urine copper excretion indexes and their biological variation were defined. In order to investigate their utility performance in screening for WD in this age group, multiple spot urine samples from six WD patients who were diagnosed at presymptomatic stage were also analysed and compared. Cut-off values useful for detection of WD were defined by receiver operator curve (ROC) analysis. Biological (inter-individual) variation of spot urine copper indexes expressed as coefficient of variation (CVg) were around 60% at this age group, which was moderate and similar to other clinically useful urine tests, such as urine albumin excretion ratio. Spot urine copper excretion strongly correlated with both urine creatinine and osmolality. Linear regression against both creatinine and osmolality showed that ∼94% of data points in healthy preschool children fell within the prediction interval, suggesting that both were useful normalisation factors. ROC showed that copper to osmolality ratio was the best index with an area under curve (AUC) greater than 0.98. Cut-off values of 0.5 μmol/L, 0.1 μmol/mmol and 0.00085 μmol/mOsmol (32 μg/L, 56 μg/g creatinine and 0.054 μg/mOsmol, respectively, in conventional units) for spot urine copper concentration, copper to creatinine ratio and copper to osmolality ratio, respectively, have potential application in the differentiation of WD patients. Based on the data, a new WD screening strategy targeting preschool children is proposed. Application of a bivariate screening strategy using spot urine copper concentration and urine osmolality may be useful in a population-wide screening program for WD among preschool children.

Urine metallomics signature as an indicator of pancreatic cancer

Urine metallomics as potential diagnostic tool for PDAC, one of the deadliest types of cancer.

Assessment of coupled Zn concentration and natural stable isotope analyses of urine as a novel probe of Zn status

Heavier Zn isotope compositions in urine compared to blood serum and an accompanying isotope-concentration trend likely reflects Zn processing in the kidneys in response to bodily Zn requirements.