Trace elements status in diabetes mellitus type 2: possible role of the interaction between molybdenum and copper in the progress of typical complications

Essential trace element and phosphatidylcholine remodeling: Implications for body composition and insulin resistance

BACKGROUND

Recent studies indicated that bioactive lipids of phosphatidylcholines (PCs) and lysophosphatidylcholines (LysoPCs) predict unhealthy metabolic phenotypes, but results remain inconsistent. To fill this knowledge gap, we investigated whether essential trace elements affect PC-Lyso PC remodeling pathways and the risk of insulin resistance (IR).

METHODS

Anthropometric and blood biochemical data (glucose, insulin, and lipoprotein-associated phospholipase A2 (Lp-PLA2)) were obtained from 99 adults. Blood essential/probably essential trace elements and lipid metabolites were respectively measured by inductively coupled plasma mass spectrometry (ICP-MS), and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS).

RESULT AND CONCLUSION

Except for LysoPC (O-18:0/0:0), an inverse V shape was observed between body weight and PC and LysoPC species. A Pearson correlation analysis showed that essential/probably-essential metals (Se, Cu, and Ni: r=-0.4∼-0.7) were negatively correlated with PC metabolites but positively correlated with LysoPC (O-18:0/0:0) (Se, Cu, and Ni: r=0.85-0.64). Quantile-g computation showed that one quantile increase in essential metals was associated with a 2.16-fold increase in serum Lp-PLA2 (β=2.16 (95 % confidence interval (CI): 0.34, 3.98), p=0.023), which are key enzymes involved in PC/Lyso PC metabolism. An interactive analysis showed that compared to those with the lowest levels (reference), individuals with the highest levels of serum PCs (pooled, M2) and the lowest essential/probably essential metals (M1) were associated with a healthier body composition and had a 76 % decreased risk of IR (odds ratio (OR)=0.24 (95 % CI: 0.06, 0.90), p<0.05). In contrast, increased exposure to LysoPC(O-18:0/0:0) (M2) and essential metals (M2) exhibited an 8.22-times highest risk of IR (OR= 8.22 (2.07, 32.57), p<0.05) as well as an altered body composition. In conclusion, overexposure to essential/probably essential trace elements may promote an unhealthy body weight and IR through modulating PC/LysoPC remodeling pathways.

The safety of magnetic resonance imaging contrast agents

Gadolinium-based contrast agents are increasingly used in clinical practice. While these pharmaceuticals are verified causal agents in nephrogenic systemic fibrosis, there is a growing body of literature supporting their role as causal agents in symptoms associated with gadolinium exposure after intravenous use and encephalopathy following intrathecal administration. Gadolinium-based contrast agents are multidentate organic ligands that strongly bind the metal ion to reduce the toxicity of the metal. The notion that cationic gadolinium dissociates from these chelates and causes the disease is prevalent among patients and providers. We hypothesize that non-ligand-bound (soluble) gadolinium will be exceedingly low in patients. Soluble, ionic gadolinium is not likely to be the initial step in mediating any disease. The Kidney Institute of New Mexico was the first to identify gadolinium-rich nanoparticles in skin and kidney tissues from magnetic resonance imaging contrast agents in rodents. In 2023, they found similar nanoparticles in the kidney cells of humans with normal renal function, likely from contrast agents. We suspect these nanoparticles are the mediators of chronic toxicity from magnetic resonance imaging contrast agents. This article explores associations between gadolinium contrast and adverse health outcomes supported by clinical reports and rodent models.

Trace element status in canine endocrine diseases

A balanced trace element status is essential for the optimal functioning of all organisms. However, their concentrations are often altered in diverse medical conditions. This study investigated the trace element profiles in plasma samples of dogs with endocrine diseases and used chemometric techniques to explore their associations with biochemical data. Thirteen elements (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se and Zn) were measured in 40 dogs with hyperadrenocorticism (HAC), 29 dogs with diabetes mellitus (DM), 11 dogs with hypothyroidism (HT) and 30 control dogs using inductively coupled plasma mass spectrometry (ICP-MS). Statistically significant differences were observed for As, Cu, Mo, Se and Zn. In comparison with the control group, the HT patients had higher As and lower Se levels, while the HAC group had higher concentrations of Mo. All three disease groups had higher Cu and Zn concentrations than the control group, with the DM group having higher Cu concentrations and the HAC group higher Zn concentrations than the other endocrinopathy groups. The chemometric analysis revealed distinctive association patterns for discriminating each pathology group and the control group. Moreover, the analysis revealed the following associations: Mo with glucose levels and Cu with fructosamine levels in the DM group, As with cortisol levels in the HAC group, and Se with TT4 levels and As with TSH levels in the HT group. The study findings provide valuable insights into the complex relationships between trace elements and endocrinopathies, elucidating the associations with biochemical markers in these diseases. Larger-scale studies are necessary to fully understand the observed relationships and explore the potential clinical applications.

The relationship between heavy metals and metabolic syndrome using machine learning

Background

Exposure to high levels of heavy metals has been widely recognized as an important risk factor for metabolic syndrome (MetS). The main purpose of this study is to assess the associations between the level of heavy metal exposure and Mets using machine learning (ML) method.

Methods

The data used in this study are from the national health and nutrition examination survey 2003-2018. According to the demographic information and heavy metal exposure level of participants, a total of 22 variables were included. Lasso was used to screen out the key variables, and 9 commonly used ML models were selected to establish the associations with the 5-fold cross validation method. Finally, we choose the SHapley Additive exPlanations (SHAP) method to explain the prediction results of Adaboost model.

Results

11,667 eligible individuals were randomly divided into two groups to train and verify the prediction model. Through lasso, characteristic variables were selected from 24 variables as predictors. The AUC (area under curve) of the models selected in this study were all greater than 0.7, and AdaBoost was the best model. The AUC value of AdaBoost was 0.807, the accuracy was 0.720, and the sensitivity was 0.792. It is noteworthy that higher levels of cadmium, body mass index, cesium, being female, and increasing age were associated with an increased probability of MetS. Conversely, lower levels of cobalt and molybdenum were linked to a decrease in the estimated probability of MetS.

Conclusion

Our study highlights the AdaBoost model proved to be highly effective, precise, and resilient in detecting a correlation between exposure to heavy metals and MetS. Through the use of interpretable methods, we identified cadmium, molybdenum, cobalt, cesium, uranium, and barium as prominent contributors within the predictive model.

The relationship between plasma nickel concentrations and type 2 diabetes mellitus risk: A protective effect within a specific range

BACKGROUND

Nickel is considered an essential nutrient for certain microbial, plant, and animal species, but its role in human health remains controversial. Some studies have reported the relationship between nickel and type 2 diabetes mellitus (T2DM), but the results are not consistent and the mechanism is not clear, which needs further exploration.

AIM

To investigate the possible correlation between nickel and T2DM.

METHODS

We conducted a case-control study of 192 patients with T2DM and 189 healthy controls at a hospital in central China. Plasma concentrations of nickel and six other trace elements were measured with inductively coupled plasma mass spectrometry. Logistic regression models, restricted cubic spline models (RCS), and Bayesian kernel machine regression (BKMR) were used to evaluate the relationship between plasma nickel and T2DM and its metabolic risk factors, as well as the presence or absence of interactions between nickel and other elements.

RESULTS

The T2DM group exhibited considerably lower plasma nickel levels than the control group (P < 0.001). Whether using a crude or adjusted model, logistic regression analysis finds a negative correlation between nickel levels and the risk of T2DM (P trend < 0.001). According to the RCS, the risk of T2DM reduces with rising nickel levels when the value is below 6.1 μg/L; nickel has a negative linear correlation with fasting plasma glucose (FPG), an inverse U-shaped connection with superoxide dismutase (SOD), and a positive linear correlation with malondialdehyde (MDA) (all P overall < 0.05). The plasma nickel concentration was positively correlated with zinc, vanadium, and chromium (r = 0.23, 0.11, and 0.19, respectively; all P < 0.05) and negatively correlated with copper (r = - 0.11, P < 0.05). In the BKMR model, interactions of nickel with zinc on T2DM and SOD, nickel with chromium on T2DM and homeostasis model assessment of β cell (HOMA-β), and nickel with copper on FPG, homeostasis model assessment of insulin (HOMA-IR), and MDA were observed.

CONCLUSION

Nickel may have a dual effect on the risk of T2DM, with a protective range of less than 6.1 μg/L. Potential interactions between nickel, copper, zinc, and chromium existed in their associations with T2DM and its metabolic risk factors.

Effects of Various Heavy Metal Exposures on Insulin Resistance in Non-diabetic Populations: Interpretability Analysis from Machine Learning Modeling Perspective

Increasing and compelling evidence has been proved that heavy metal exposure is involved in the development of insulin resistance (IR). We trained an interpretable predictive machine learning (ML) model for IR in the non-diabetic populations based on levels of heavy metal exposure. A total of 4354 participants from the NHANES (2003-2020) with complete information were randomly divided into a training set and a test set. Twelve ML algorithms, including random forest (RF), XGBoost (XGB), logistic regression (LR), GaussianNB (GNB), ridge regression (RR), support vector machine (SVM), multilayer perceptron (MLP), decision tree (DT), AdaBoost (AB), Gradient Boosting Decision Tree (GBDT), Voting Classifier (VC), and K-Nearest Neighbour (KNN), were constructed for IR prediction using the training set. Among these models, the RF algorithm had the best predictive performance, showing an accuracy of 80.14%, an AUC of 0.856, and an F1 score of 0.74 in the test set. We embedded three interpretable methods, the permutation feature importance analysis, partial dependence plot (PDP), and Shapley additive explanations (SHAP) in RF model for model interpretation. Urinary Ba, urinary Mo, blood Pb, and blood Cd levels were identified as the main influencers of IR. Within a specific range, urinary Ba (0.56-3.56 µg/L) and urinary Mo (1.06-20.25 µg/L) levels exhibited the most pronounced upwards trend with the risk of IR, while blood Pb (0.05-2.81 µg/dL) and blood Cd (0.24-0.65 µg/L) levels showed a declining trend with IR. The findings on the synergistic effects demonstrated that controlling urinary Ba levels might be more crucial for the management of IR. The SHAP decision plot offered personalized care for IR based on heavy metal control. In conclusion, by utilizing interpretable ML approaches, we emphasize the predictive value of heavy metals for IR, especially Ba, Mo, Pb, and Cd.

Associations between patterns of blood heavy metal exposure and health outcomes: insights from NHANES 2011-2016

BACKGROUND

Extensive research has explored the association between heavy metal exposure and various health outcomes, including malignant neoplasms, hypertension, diabetes, and heart diseases. This study aimed to investigate the relationship between patterns of exposure to a mixture of seven heavy metals and these health outcomes.

METHODS

Blood samples from 7,236 adults in the NHANES 2011-2016 studies were analyzed for levels of cadmium, manganese, lead, mercury, selenium, copper, and zinc. Cluster analysis and logistic regression identified three distinct patterns of mixed heavy metal exposure, and their associations with health outcomes were evaluated.

RESULTS

Pattern 1 exhibited higher odds ratios (ORs) for malignancy during NHANES 2011-2012 (OR = 1.33) and 2015-2016 (OR = 1.29) compared to pattern 2. Pattern 3 showed a lower OR for malignancy during NHANES 2013-2014 (OR = 0.62). For hypertension, pattern 1 displayed higher ORs than pattern 2 for NHANES 2011-2012 (OR = 1.26), 2013-2014 (OR = 1.31), and 2015-2016 (OR = 1.41). Pattern 3 had lower ORs for hypertension during NHANES 2013-2014 (OR = 0.72) and 2015-2016 (OR = 0.67). In terms of heart diseases, pattern 1 exhibited higher ORs than pattern 2 for NHANES 2011-2012 (OR = 1.34), 2013-2014 (OR = 1.76), and 2015-2016 (OR = 1.68). Pattern 3 had lower ORs for heart diseases during NHANES 2013-2014 (OR = 0.59) and 2015-2016 (OR = 0.52). However, no significant trend was observed for diabetes. All three patterns showed the strongest association with hypertension among the health outcomes studied.

CONCLUSIONS

The identified patterns of seven-metal mixtures in NHANES 2011-2016 were robust. Pattern 1 exhibited higher correlations with hypertension, heart disease, and malignancy compared to pattern 2, suggesting an interaction between these metals. Particularly, the identified patterns could offer valuable insights into the management of hypertension in healthy populations.

Copper and Diabetes: Current Research and Prospect

Copper is an essential trace metal for normal cellular functions; a lack of copper is reported to impair the function of important copper-binding enzymes, while excess copper could lead to cell death. Numerous studies have shown an association between dietary copper consumption or plasma copper levels and the incidence of diabetes/diabetes complications. And experimental studies have revealed multiple signaling pathways that are triggered by copper shortages or copper overload in diabetic conditions. Moreover, studies show that treated with copper chelators improve vascular function, maintain copper homeostasis, inhibit cuproptosis, and reduce cell toxicity, thereby alleviating diabetic neuropathy, retinopathy, nephropathy, and cardiomyopathy. However, the mechanisms reported in these studies are inconsistent or even contradictory. This review summarizes the precise and tight regulation of copper homeostasis processes, and discusses the latest progress in the association of diabetes and dietary copper/plasma copper. Further, the study pays close attention to the therapeutic potential of copper chelators and copper in diabetes and its complications, and hopes to provide new insight for the treatment of diabetes.

Blood manganese and non-alcoholic fatty liver disease in a high manganese exposure area in China

BACKGROUND AND AIMS

Manganese (Mn) deficiency and intoxication may affect nonalcoholic fatty liver disease (NAFLD) risk differently. We aimed to explore the association between blood Mn and NAFLD in an area with high Mn exposure in drinking water.

METHODS

We conducted a case-control study among 1407 patients with NAFLD and 1774 sex- and age-matched healthy controls in a physical examination population in Zhoushan hospital, Zhejiang province in China. We used the restricted cubic splines method to investigate the dose-response relationship. Logistic regression models were applied to determine the risk of NAFLD, and severity of NAFLD.

RESULTS

The blood Mn concentration was higher in the NAFLD group than in the control group in women (16.1 ± 6.2 μg/L vs. 14.7 ± 6.4 μg/L, P = 0.022) and men (14.5 ± 6.3 μg/L vs. 13.6 ± 6.8 μg/L, P < 0.001). We found an inverted L shape relationship between blood Mn and NAFLD in both women and men. Compared to the lowest quartile, the adjusted odds ratio (OR) and 95% confidence interval (CI) of NAFLD for the highest quartile group was 1.646(1.222,2.217), 1.494(1.082,2.061), and 3.146(1.285,7.701) for the total population, men, and women. The positive relationship was only observed in those with fibrosis-4 score < 1.30 and normal alanine transaminase. Stratified analysis showed an interaction between smoking (P = 0.073), alcohol drinking (P = 0.013), and Mn, with a more prominent effect on the NAFLD in the never-smokers (OR = 2.153, 95% CI 1.408-3.290) and drinkers (OR = 2.596, 95% CI 1.608-4.191).

CONCLUSION

Higher blood Mn is associated with an elevated NAFLD risk in the high Mn exposure areas, especially in nonsmokers and drinkers. Further studies are needed to verify this result in the areas with high Mn exposure.

Consequences of Disturbing Manganese Homeostasis

Manganese (Mn) is an essential trace element with unique functions in the body; it acts as a cofactor for many enzymes involved in energy metabolism, the endogenous antioxidant enzyme systems, neurotransmitter production, and the regulation of reproductive hormones. However, overexposure to Mn is toxic, particularly to the central nervous system (CNS) due to it causing the progressive destruction of nerve cells. Exposure to manganese is widespread and occurs by inhalation, ingestion, or dermal contact. Associations have been observed between Mn accumulation and neurodegenerative diseases such as manganism, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. People with genetic diseases associated with a mutation in the gene associated with impaired Mn excretion, kidney disease, iron deficiency, or a vegetarian diet are at particular risk of excessive exposure to Mn. This review has collected data on the current knowledge of the source of Mn exposure, the experimental data supporting the dispersive accumulation of Mn in the brain, the controversies surrounding the reference values of biomarkers related to Mn status in different matrices, and the competitiveness of Mn with other metals, such as iron (Fe), magnesium (Mg), zinc (Zn), copper (Cu), lead (Pb), calcium (Ca). The disturbed homeostasis of Mn in the body has been connected with susceptibility to neurodegenerative diseases, fertility, and infectious diseases. The current evidence on the involvement of Mn in metabolic diseases, such as type 2 diabetes mellitus/insulin resistance, osteoporosis, obesity, atherosclerosis, and non-alcoholic fatty liver disease, was collected and discussed.

The Link between Trace Metal Elements and Glucose Metabolism: Evidence from Zinc, Copper, Iron, and Manganese-Mediated Metabolic Regulation

Trace metal elements are of vital importance for fundamental biological processes. They function in various metabolic pathways after the long evolution of living organisms. Glucose is considered to be one of the main sources of biological energy that supports biological activities, and its metabolism is tightly regulated by trace metal elements such as iron, zinc, copper, and manganese. However, there is still a lack of understanding of the regulation of glucose metabolism by trace metal elements. In particular, the underlying mechanism of action remains to be elucidated. In this review, we summarize the current concepts and progress linking trace metal elements and glucose metabolism, particularly for the trace metal elements zinc, copper, manganese, and iron.

Does the Micronutrient Molybdenum Have a Role in Gestational Complications and Placental Health?

Molybdenum is an essential trace element for human health and survival, with molybdenum-containing enzymes catalysing multiple reactions in the metabolism of purines, aldehydes, and sulfur-containing amino acids. Recommended daily intakes vary globally, with molybdenum primarily sourced through the diet, and supplementation is not common. Although the benefits of molybdenum as an anti-diabetic and antioxidant inducer have been reported in the literature, there are conflicting data on the benefits of molybdenum for chronic diseases. Overexposure and deficiency can result in adverse health outcomes and mortality, although physiological doses remain largely unexplored in relation to human health. The lack of knowledge surrounding molybdenum intake and the role it plays in physiology is compounded during pregnancy. As pregnancy progresses, micronutrient demand increases, and diet is an established factor in programming gestational outcomes and maternal health. This review summarises the current literature concerning varied recommendations on molybdenum intake, the role of molybdenum and molybdoenzymes in physiology, and the contribution these play in gestational outcomes.

A method for reliable quantification of mercury in occupational and environmental medical urine samples by inductively coupled plasma mass spectrometry

Over the last years, inductively coupled plasma mass spectrometry (ICP-MS) has been applied as a method for human-biomonitoring of metals in the concentration range of occupational and environmental medicine. In large scale routine monitoring, the determination of mercury (Hg) by ICP-MS remains challenging due to several reasons. Amongst others, stability of dissolved Hg and avoiding memory effects are the key facts for reliable quantification. To address these issues, we developed a robust approach for biomonitoring of mercury in human urine samples by ICP-MS. Using a solution containing HNO₃, HCl and thiourea, prepared samples and calibrators were stabilized for up to 72 h. A rinse time of only 30 seconds efficiently prevented contamination of consecutive samples with Hg concentrations up to 30 μg L^-1, hence significantly reducing acquisition times compared to published methods. Recovery experiments revealed iridium as an ideal internal standard to compensate matrix effects independently from creatinine concentration. Recoveries of 95.0-104.0% were obtained for Hg levels covering the range of biomonitoring guidance values established by the German Human-Biomonitoring Commission. Excellent intra-day precision and inter-day precision of ≤3.0% for two different Hg levels were achieved. The detection and quantification limit accounted for 21.7 ng L^-1 and 65.6 ng L^-1, respectively, enabling reliable quantification even in the range of environmental background exposures. Additionally, the method was externally validated by successful participation in the inter-laboratory comparison program G-EQUAS. With the developed method, we hence provide a sensitive and robust tool for mercury exposure assessments in future large scale human-biomonitoring studies.

Sex-specific and dose-response relationships of urinary cobalt and molybdenum levels with glucose levels and insulin resistance in U.S. adults

Growing studies have linked metal exposure to diabetes risk. However, these studies had inconsistent results. We used a multiple linear regression model to investigate the sex-specific and dose-response associations between urinary metals (cobalt (Co) and molybdenum (Mo)) and diabetes-related indicators (fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), homeostasis model assessment for insulin resistance (HOMA-IR), and insulin) in a cross-sectional study based on the United States National Health and Nutrition Examination Survey. The urinary metal concentrations of 1423 eligible individuals were stratified on the basis of the quartile distribution. Our results showed that the urinary Co level in males at the fourth quartile (Q4) was strongly correlated with increased FPG (β = 0.61, 95% CI: 0.17-1.04), HbA1c (β = 0.31, 95% CI: 0.09-0.54), insulin (β = 8.18, 95% CI: 2.84-13.52), and HOMA-IR (β = 3.42, 95% CI: 1.40-5.44) when compared with first quartile (Q1). High urinary Mo levels (Q4 vs. Q1) were associated with elevated FPG (β = 0.46, 95% CI: 0.17-0.75) and HbA1c (β = 0.27, 95% CI: 0.11-0.42) in the overall population. Positive linear dose-response associations were observed between urinary Co and insulin (P_nonlinear = 0.513) and HOMA-IR (P_nonlinear = 0.736) in males, as well as a positive linear dose-response relationship between urinary Mo and FPG (P_nonlinear = 0.826) and HbA1c (P_nonlinear = 0.376) in the overall population. Significant sex-specific and dose-response relationships were observed between urinary metals (Co and Mo) and diabetes-related indicators, and the potential mechanisms should be further investigated.

Recent advances in the application of ionomics in metabolic diseases

Trace elements and minerals play a significant role in human health and diseases. In recent years, ionomics has been rapidly and widely applied to explore the distribution, regulation, and crosstalk of different elements in various physiological and pathological processes. On the basis of multi-elemental analytical techniques and bioinformatics methods, it is possible to elucidate the relationship between the metabolism and homeostasis of diverse elements and common diseases. The current review aims to provide an overview of recent advances in the application of ionomics in metabolic disease research. We mainly focuses on the studies about ionomic or multi-elemental profiling of different biological samples for several major types of metabolic diseases, such as diabetes mellitus, obesity, and metabolic syndrome, which reveal distinct and dynamic patterns of ion contents and their potential benefits in the detection and prognosis of these illnesses. Accumulation of copper, selenium, and environmental toxic metals as well as deficiency of zinc and magnesium appear to be the most significant risk factors for the majority of metabolic diseases, suggesting that imbalance of these elements may be involved in the pathogenesis of these diseases. Moreover, each type of metabolic diseases has shown a relatively unique distribution of ions in biofluids and hair/nails from patients, which might serve as potential indicators for the respective disease. Overall, ionomics not only improves our understanding of the association between elemental dyshomeostasis and the development of metabolic disease but also assists in the identification of new potential diagnostic and prognostic markers in translational medicine.

Urine trace element disorder along with renal function injury in vitamin D deficient diabetic rats and intervention effect of 1α,25-dihydroxyvitamin D3

Introduction

Trace element metabolism disorders are often secondary to disorders of glucose metabolism in diabetes. Although 1α,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] could ameliorate abnormal glucose metabolism in the development of diabetes, the effect on trace element metabolism is unclear. The objective of this study was to evaluate the influence of 1,25(OH)₂D₃ on urinary excretions of trace elements in Zucker diabetic fatty (ZDF) rats.

Methods

At 6 weeks of age, male ZDF (n = 40) rats were subdivided into four groups: diabetic model (ZDF), low-dose (ZDF + VL, 2 μg/kg⋅bw), middle-dose (ZDF + VM, 8 μg/kg⋅bw) and high-dose (ZDF + VH, 16 μg/kg⋅bw) 1,25(OH)₂D₃ groups. Another 10 Zucker lean (ZL) rats served as a control group. All rats were given vitamin D deficient Purina #5008 chow and the intervention groups were given the corresponding dose of 1,25(OH)₂D₃ by gavage on alternate days for 7 weeks. Microalbuminuria (MALB) and urinary creatinine concentration were detected by a biochemical autoanalyzer. Urine trace element concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS) and were corrected by urinary creatinine.

Results

Throughout the intervention phase, MALB, UACR and urinary creatinine levels in the ZDF group were significantly higher than those in the ZL group, and showed a gradual increase with the prolongation of the intervention time. These changes were reversed in a dose-dependent manner after 1,25(OH)₂D₃ intervention (P < 0.05). Correspondingly, most of the urinary trace element excretions in the ZDF rats were significantly increased compared with the ZL group, and 1,25(OH)₂D₃ intervention significantly reduced the urinary copper (Cu), zinc (Zn), selenium (Se) and molybdenum (Mo) levels in the ZDF rats (P < 0.05), especially in the medium and high dose groups.

Conclusion

1,25(OH)₂D₃ had improvement effects on urinary Cu, Zn, Se, and Mo excretions in ZDF rats, suggesting that it may be related to the reduction of diabetic renal impairment and renal oxidative damage.

Association Between Essential and Non-essential Metals, Body Composition, and Metabolic Syndrome in Adults

Growing evidence indicates that metal exposure is associated with metabolic syndrome (MetS); however, mixed results have been reported. The aim of this study was to clarify associations of exposure to essential and non-essential metals with body composition and risks of obesity and MetS. Anthropometry and blood biochemistry of metabolic parameters were obtained from 150 middle-aged Taiwanese adults. Plasma metals were assessed using inductively coupled plasma mass spectrometry, and body compositions were measured by a bioelectrical impedance analysis (BIA). The essential metals of copper (Cu), manganese (Mn), and chromium (Cr) were positively correlated with the body fat mass but inversely correlated with the skeletal muscle mass (all p < 0.05). An adjusted logistic regression showed that Mn [odds ratio (OR) = 1.624 (95% confidence interval 1.072, 2.462), p = 0.02] and, to a lesser extent, Cu [OR = 1.501 (0.985, 2.292), p = 0.059] predicted abdominal obesity, while plasma Cu [OR = 2.211 (1.146, 4.266), p = 0.02] and zinc (Zn) [OR = 2.228 (1.048, 4.736) p = 0.04] predicted MetS. Significant correlations between dyslipidemia and lithium [OR = 1.716 (1.080, 2.726)], Cu [OR = 2.210 (1.415, 3.454)], Mn [OR = 2.200 (1.320, 3.666)], molybdenum [OR = 1.853 (1.160, 2.958)], and Zn [OR = 1.993 (1.186, 3.349)], and between boron [OR = 2.583 (1.137, 5.868)] and hyperglycemia were observed (all p < 0.05). Exposure to essential metals may affect the body composition and metabolic profiles, exacerbating the risk of MetS.

Association of CYP19A1 Gene, Plasma Zinc, and Urinary Zinc with the Risk of Type 2 Diabetes Mellitus in a Chinese Population

To explore the effects of CYP19A1 gene polymorphisms, plasma zinc, and urinary zinc levels and their interactions on type 2 diabetes mellitus (T2DM) in residents of Gongcheng County, Guangxi, China. The case-control study was used for the investing. The MassARRAY System was applied to genotype the CYP19A1 genes rs752760, rs10046, rs10459592, and rs700518 in 540 study subjects. Plasma and urinary zinc concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS). Conditional logistic regression showed that rs752760 and plasma zinc were associated with T2DM risks with ORs of 0.593 (95% CI: 0.371-0.948) and 0.563 (95% CI: 0.356-0.889), respectively. Unconditional logistic regression analysis showed an association between urinary zinc levels and the risk of T2DM as well, with an OR of 0.352 (95% CI: 0.212-0.585). The results of the multiplicative interaction model showed that the rs752760 T allele was associated with a significantly reduced risk of T2DM with moderate/low plasma zinc levels, with ORs of 0.340 (95% CI: 0.161-0.715) and 0.583 (95% CI: 0.346-0.981), respectively, and the rs752760 T allele was also associated with a significantly decreased risk of T2DM with moderate/low urinary zinc levels, with ORs of 0.358 (95% CI: 0.201-0.635) and 0.321 (95% CI: 0.183-0.562), respectively. CYP19A1 rs752760 T allele and moderate/low plasma/urinary zinc levels reduce the risk of T2DM.

Is There a Connection between the Metabolism of Copper, Sulfur, and Molybdenum in Alzheimer’s Disease? New Insights on Disease Etiology

Alzheimer’s disease (AD) and other forms of dementia was ranked 3rd in both the Americas and Europe in 2019 in a World Health Organization (WHO) publication listing the leading causes of death and disability worldwide. Copper (Cu) imbalance has been reported in AD and increasing evidence suggests metal imbalance, including molybdenum (Mo), as a potential link with AD occurrence.We conducted an extensive literature review of the last 60 years of research on AD and its relationship with Cu, sulfur (S), and Mo at out of range levels.Weanalyzed the interactions among metallic elements’ metabolisms;Cu and Mo are biological antagonists, Mo is a sulfite oxidase and xanthine oxidase co-factor, and their low activities impair S metabolism and reduce uric acid, respectively. We found significant evidence in the literature of a new potential mechanism linking Cu imbalance to Mo and S abnormalities in AD etiology: under certain circumstances, the accumulation of Cu not bound to ceruloplasmin might affect the transport of Mo outside the blood vessels, causing a mild Mo deficiency that might lowerthe activity of Mo and S enzymes essential for neuronal activity. The current review provides an updated discussion of the plausible mechanisms combining Cu, S, and Mo alterations in AD.

Association between serum manganese levels and diabetes in chinese adults with hypertension

Manganese (Mn) is an essential trace metal element that is associated with diabetes; however, the results of previous studies are inconsistent. Furthermore, few studies have been conducted in a hypertensive population. The purpose of this study is to explore the relationship between manganese and diabetes in a population with hypertension. A cross‐sectional study was conducted, including 2575 hypertensive individuals from 14 provinces in China. Serum manganese concentrations were measured by the inductively coupled plasma mass spectrometry (ICP‐MS) method. And logistic regression models were used to analyze the association between serum manganese and the risk of diabetes. The prevalence of diabetes was 27.0% in this hypertensive population. In logistic regression models, the odds ratios (95% confidence interval) for diabetes in tertile subgroups were 1.40 (1.12, 1.76) and 1.32 (1.05, 1.65) for tertiles 1 and tertiles 3, respectively, compared to tertile 2 (reference). Additionally, an interaction between sex and manganese was observed. The odds ratios (95% confidence interval) for diabetes were 1.29 (0.95, 1.75) and 0.96 (0.70, 1.31) for tertiles 1 and tertiles 3 among males, and 1.44 (1.01, 2.04) and 1.81 (1.29, 2.55) for tertiles 1 and tertiles 3 among females, respectively, compared to tertile 2. In conclusion, a U‐shaped association between serum manganese and diabetes was observed in a Chinese population with hypertension, and the association was modified by sex.

Methylmercury Induces Mitochondria- and Endoplasmic Reticulum Stress-Dependent Pancreatic β-Cell Apoptosis via an Oxidative Stress-Mediated JNK Signaling Pathway

Methylmercury (MeHg), a long-lasting organic pollutant, is known to induce cytotoxic effects in mammalian cells. Epidemiological studies have suggested that environmental exposure to MeHg is linked to the development of diabetes mellitus (DM). The exact molecular mechanism of MeHg-induced pancreatic β-cell cytotoxicity is still unclear. Here, we found that MeHg (1-4 μM) significantly decreased insulin secretion and cell viability in pancreatic β-cell-derived RIN-m5F cells. A concomitant elevation of mitochondrial-dependent apoptotic events was observed, including decreased mitochondrial membrane potential and increased proapoptotic (Bax, Bak, p53)/antiapoptotic (Bcl-2) mRNA ratio, cytochrome c release, annexin V-Cy3 binding, caspase-3 activity, and caspase-3/-7/-9 activation. Exposure of RIN-m5F cells to MeHg (2 μM) also induced protein expression of endoplasmic reticulum (ER) stress-related signaling molecules, including C/EBP homologous protein (CHOP), X-box binding protein (XBP-1), and caspase-12. Pretreatment with 4-phenylbutyric acid (4-PBA; an ER stress inhibitor) and specific siRNAs for CHOP and XBP-1 significantly inhibited their expression and caspase-3/-12 activation in MeHg-exposed RIN-mF cells. MeHg could also evoke c-Jun N-terminal kinase (JNK) activation and reactive oxygen species (ROS) generation. Antioxidant N-acetylcysteine (NAC; 1mM) or 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox; 100 μM) markedly prevented MeH-induced ROS generation and decreased cell viability in RIN-m5F cells. Furthermore, pretreatment of cells with SP600125 (JNK inhibitor; 10 μM) or NAC (1 mM) or transfection with JNK-specific siRNA obviously attenuated the MeHg-induced JNK phosphorylation, CHOP and XBP-1 protein expression, apoptotic events, and insulin secretion dysfunction. NAC significantly inhibited MeHg-activated JNK signaling, but SP600125 could not effectively reduce MeHg-induced ROS generation. Collectively, these findings demonstrate that the induction of ROS-activated JNK signaling is a crucial mechanism underlying MeHg-induced mitochondria- and ER stress-dependent apoptosis, ultimately leading to β-cell death.

Serum selenium concentrations and risk of all-cause and heart disease mortality among individuals with type 2 diabetes

BACKGROUND

The impact of selenium status on the long-term health of people with type 2 diabetes (T2D) remains unclear.

OBJECTIVES

To prospectively examine the association of serum selenium concentrations with all-cause and heart disease mortality among individuals with T2D.

METHODS

This analysis included 3199 adults with T2D from the third NHANES (NHANES III) and NHANES (2003-2004, 2011-2014). Mortality from heart disease and all causes was linked to National Death Index mortality data. Cox proportional hazard models were used to estimate HRs and 95% CIs.

RESULTS

The median (IQR) concentration of serum selenium was 127.0 (115.0, 139.1) µg/L. During an average 12.6-y follow-up, 1693 deaths were documented, including 425 heart disease deaths. Compared with participants in the lowest quartile of selenium, the multivariate-adjusted HRs (95% CIs) for participants in the highest quartile were 0.69 (0.54, 0.89) for all-cause mortality (P-trend = 0.002) and 0.66 (0.45, 0.99) for heart disease mortality (P-trend = 0.03). In addition, a linear dose-response relation between serum selenium (range: 89-182 µg/L) and mortality was observed. For per-unit increment in natural log-transformed serum selenium, there was a 64% lower risk of all-cause mortality and a 66% lower risk of heart disease mortality (both P < 0.05). Similar results were observed when stratifying by age, sex, race, smoking status, BMI, physical activity, diabetes duration, and HbA1c concentrations.

CONCLUSIONS

Our study suggested that higher selenium concentration was associated with lower all-cause and heart disease mortality among individuals with T2D. More studies are needed to confirm these findings.

Cadmium exposure and risk of diabetes and prediabetes: A systematic review and dose-response meta-analysis

BACKGROUND

Cadmium exposure has been associated with increased diabetes risk in several studies, though there is still considerable debate about the magnitude and shape of the association.

OBJECTIVE

To perform a systematic review and meta-analysis of observational studies investigating the relation between cadmium exposure and risk of type 2 diabetes and prediabetes, and to summarize data on the magnitude and shape of the association.

DATA SOURCE

After conducting an online literature search through October 1, 2021, we identified 42 eligible studies investigating the association between cadmium exposure and risk of diabetes and prediabetes.

STUDY ELIGIBILITY CRITERIA

We included studies that assessed cadmium exposure through biomarker levels; examined type 2 diabetes or prediabetes among outcomes; and reported effect estimates for cadmium exposure for meta-analysis only.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies were evaluated using ROBINS-E risk of bias tool. We quantitively assessed the relation between exposure and study outcomes using one-stage dose-response meta-analysis with a random effects meta-analytical model.

RESULTS

In the meta-analysis, comparing highest-versus-lowest cadmium exposure levels, summary relative risks (RRs) for type 2 diabetes were 1.24 (95% confidence interval 0.96-1.59), 1.21 (1.00-1.45), and 1.47 (1.01-2.13) for blood, urinary, and toenail matrices, respectively. Similarly, there was an increased risk of prediabetes for cadmium concentrations in both urine (RR = 1.41, 95% CI: 1.15-1.73) and blood (RR = 1.38, 95% CI: 1.16-1.63). In the dose-response meta-analysis, we observed a consistent linear positive association between cadmium exposure and diabetes risk, with RRs of 1.25 (0.90-1.72) at 2.0 µg/g of creatinine. Conversely for blood cadmium, diabetes risk appeared to increase only above 1 µg/L. Prediabetes risk increased up to approximately 2 µg/g creatinine above which it reached a plateau with RR of 1.42 (1.12-1.76) at 2 µg/g creatinine.

LIMITATIONS AND CONCLUSIONS

This analysis provides moderate-certainty evidence for a positive association between cadmium exposure (measured in multiple matrices) and risk of both diabetes and prediabetes.

Nutrients and Dietary Approaches in Patients with Type 2 Diabetes Mellitus and Cardiovascular Disease: A Narrative Review

Cardiovascular disease (CVD) is the most common cause of morbidity and mortality in developed countries. The prevalence of CVD is much higher in patients with type 2 diabetes mellitus (T2DM), who may benefit from lifestyle changes, which include adapted diets. In this review, we provide the role of different groups of nutrients in patients with T2DM and CVD, as well as dietary approaches that have been associated with better and worse outcomes in those patients. Many different diets and supplements have proved to be beneficial in T2DM and CVD, but further studies, guidelines, and dietary recommendations are particularly required for patients with both diseases.

The Association Between Trace Elements and Osmolality in Plasma and Aqueous Humor Fluid in Diabetic Rabbits

Trace element metabolism plays an important role in the formation of diabetes and complications of diabetes. Although trace elements changes in lenses in diabetic cataract and glaucoma formation have been investigated, there were few studies evaluating trace elements levels in plasma and aqueous humor fluid in diabetic and non-diabetic conditions. Therefore, we aimed to investigate zinc (Zn), copper (Cu), and chromium (Cr) levels in plasma and aqueous humor fluids of rabbits in the diabetic rabbit model. New Zealand male rabbits were divided into two groups as control (n = 8), and diabetes (n = 8) induced by alloxane. At the end of the experimental period, the osmolality in blood, plasma, and aqueous humor fluids from rabbits were measured by osmometer and Zn, Cu, and Cr levels in plasma and aqueous humor fluid were measured by inductively coupled plasma-optical emission spectrophotometer (ICP-OES). The osmolality in blood, plasma, and aqueous humor fluid of the diabetic group was significantly increased compared to the control group (respectively p < 0.01, p < 0.001, p < 0.001). It was analyzed that plasma Zn and Cu levels of diabetic rabbits increased significantly (respectively, p < 0.01; p < 0.001), whereas Cr level significantly decreased according to the control group (p < 0.01). It was observed that Cr and Zn levels in aqueous humor fluid in diabetes group decreased (respectively p < 0.001 and p < 0.01), and a significantly increased in Cu level (p < 0.001) compared to the control group. Related with these changes that may occur in the eye due to the measured parameters, we consider that comparative studies of these types of diabetic animal models would be useful in the evaluation of diabetes and its complications.

Protective Effects of Sodium Para-aminosalicylic Acid on Manganese-Induced Damage in Rat Pancreas

Sodium p-aminosalicylic acid (PAS-Na) has been previously shown to protect the brain from manganese (Mn)-induced toxicity. However, the efficacy of PAS-Na in protecting other organs from Mn toxicity and the mechanisms associated with this protection have yet to be addressed. Therefore, here, we assessed pancreatic damage in response to Mn treatment and the efficacy of PAS-Na in limiting this effect, along with specific mechanisms that mediate PAS-Na's protection. Mn exposure led to increased blood Mn content in dose- and time-dependent manner. Furthermore, subchronic Mn exposure (20 mg/kg for 8 weeks) led to pancreatic damage in a dose-dependent manner. In addition, the elevated Mn levels increased iron and decreased zinc and magnesium content in the pancreas. These effects were noted even 8 weeks after Mn exposure cessation. Mn exposure also affected the levels of amylase, lipase, and inflammatory factors such as tumor necrosis factor (TNF-α) and interleukin-1 β (IL-1β). PAS-Na significantly inhibited the increase in Mn concentration in both blood and pancreas, restored Mn-induced pancreatic damage, reversed the Mn-induced alterations in metal levels, and restored amylase and lipase concentrations. Taken together, we conclude that in rats, PAS-Na shows pharmacological efficacy in protecting the pancreas from Mn-induced damage.

Use of human teardrop fluid for the determination of trace elements in healthy individuals and diabetic patients

BACKGROUND

The use of unconventional biological materials in human trace element studies has increased in terms of published research studies. The aim of present study was to develop and validate the use of teardrop fluid for determining trace element levels in the human body. No study has been published in this area yet. This is a new non-invasive approach in the possible early diagnosis of the pathogenesis of type 2 diabetes.

MATERIALS AND METHODS

Human teardrop fluid samples were obtained from Karbala (Iraq) (n = 111) healthy individuals and with type 2 diabetes (n = 44); and London (UK) healthy individuals (n = 18). The levels of V, Cr, Mn, Fe, Cu, Zn, As, Sr and Cd were determined using an inductively coupled plasma mass equipped with collision cell technology for polyatomic ion correction (ICP-MS).

STATISTICAL ANALYSIS

Discriminate function analysis (DFA) was carried out to determine the set of variables that discriminated between the trace elements in teardrop fluid samples from healthy individuals and diabetic patients.

RESULTS

The trace element levels of human teardrop fluid are similar for many elements to that reported for human blood serum in the literature. This is interesting since they have different physiological functions, although overall they are mainly water containing electrolytes (∼ 90 %) and solids (antibodies, hormones, etc). In general, for the study groups in Karbala, Iraq, significantly higher teardrop fluid levels of Mn and Sr were found in type 2 diabetic patients when compared with healthy individuals (evaluated using an F-test and a two-tailed t-test). The levels of V, Cu and As were found to be significantly higher (P < 0.05) in healthy individuals than type 2 diabetic patients. Although the levels of Fe and Zn were slightly higher in type 2 diabetic patients than healthy cases, the differences were not statistically significant (P > 0.05). Cr and Cd were found to have similar levels for both study groups. Significantly higher teardrop fluid levels of V, Cr, Mn, Fe, Zn, As and Sr were found in healthy individuals from Karbala (Iraq) when compared with those from London (UK). In contrast, the levels of Cd observed to be significantly higher in London (UK) than Karbala. No statistical difference was found for Cu between the two healthy groups.

STATISTICAL ANALYSIS

Discriminate analysis showed that human teardrop fluid V, Mn, Zn, As, Sr and Cd levels could be used to discriminate between healthy and type 2 diabetes study groups in Karbala, Iraq (83 % of cases correctly classified).

CONCLUSION

The use of human teardrop fluid for determining the trace element levels of human health conditions has been evaluated. Trace elemental levels are like that for blood serum which is widely used as an invasive method for assessing human health conditions. Sample collection for teardrop fluid is non-invasive and the application has potential for determining the trace element levels in healthy individuals and disorder conditions (like type 2 diabetes) in countries where cultural and gender sensitivity are issues with respect to the collection methods used for other body fluid samples.

Sex differences in the link between blood cobalt concentrations and insulin resistance in adults without diabetes

Background

Little is known about the effects of environmental cobalt exposure on insulin resistance (IR) in the general adult population. We investigated the association between cobalt concentration and IR.

Methods

A total of 1281 subjects aged more than 20 years with complete blood cobalt data were identified from the National Health and Nutrition Examination Survey (NHANES) 2015–2016 cycle. Blood cobalt levels were analyzed for their association with IR among all populations and subgroups by sex. Regression coefficients and 95% confidence intervals (CIs) of blood cobalt concentrations in association with fasting glucose, insulin and homeostatic model assessment of insulin resistance (HOMA-IR) were estimated using multivariate linear regression after adjusting for age, sex, ethnicity, alcohol consumption, body mass index, education level, and household income. A multivariate generalized linear regression analysis was further carried out to explore the association between cobalt exposure and IR.

Results

A negative association between blood cobalt concentration (coefficient = − 0.125, 95% CI − 0.234, − 0.015; P = 0.026) and HOMA-IR in female adults in the age- and sex-adjusted model was observed. However, no associations with HOMA-IR, fasting glucose, or insulin were found in the overall population. In the generalized linear models, participants with the lowest cobalt levels had a 2.74% (95% CI 0.04%, 5.50%) increase in HOMA-IR (P for trend = 0.031) compared with subjects with the highest cobalt levels. Restricted cubic spline regression suggested that a non-linear relationship may exist between blood cobalt and HOMA-IR.

Conclusions

These results provide epidemiological evidence that low levels of blood cobalt are negatively associated with HOMA-IR in female adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-021-00966-w.

Streptozotocin (STZ)-Induced Diabetes Affects Tissue Trace Element Content in Rats in a Dose-Dependent Manner

The objective of the present study was investigation of tissue trace element distribution in a streptozotocin model of DM1 in rats. DM1 was modeled in 2-month-old male Wistar rats (n = 30) using intraperitoneal injection of 45 mg/kg b.w. (STZ1) and 55 mg/kg b.w. streptozotocin (STZ2), whereas control animals were injected with physiological saline. The rats were subjected to oral glucose tolerance test (OGTT) and HbA1c level assessment at day 14. At day 30, blood serum, liver, kidney, and heart samples were collected for tissue trace element assessment using inductively coupled plasma mass spectrometry (ICP-MS). STZ-treated rats were characterized by lack of significant weight gain and elevated HbA1c and blood glucose levels. ICP-MS analysis demonstrated a dose-dependent accumulation of Cu, Mn, Mo, and Se levels in the liver. Correspondingly, the dose-dependent increase in renal Cu, Mn, V, and Zn levels was significant, whereas the observed trend for kidney V and Mo accumulation was nearly significant. The patterns of trace element content in the myocardium of STZ-exposed rats were quite different from those observed for liver and kidney. Only cardiac Zn content was characterized by a significant decrease. Serum Co, Cr, Cu, Se, V, and Mo levels were characterized by a significant decrease in response to STZ-induced diabetes. Generally, the obtained data demonstrate that diabetes is associated with altered copper, manganese, molybdenum, chromium, and vanadium handling. In turn, only altered Zn status may provide a link to diabetic cardiotoxicity. However, the particular mechanisms of both impaired metal handling in STZ diabetes and their potential anti-diabetic activity require further investigation.

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.

Sex-specific associations of blood and urinary manganese levels with glucose levels, insulin resistance and kidney function in US adults: National health and nutrition examination survey 2011-2016

Exposures to heavy metals play a role in the etiopathogenesis of diabetes. Epidemiological studies investigating a potential sex-specific linkage between manganese (Mn) exposures and glucose homeostasis are rare. We comprehensively estimated the associations of blood and urinary Mn levels with fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), homeostasis model assessment for insulin resistance (HOMA-IR), insulin, and estimated glomerular filtration rate (eGFR) among 1417 adults in the US National Health and Nutrition Examination Survey (NHANES) 2011-2016. We further examined the potential heterogeneities by sex and joint-effects of multiple metal exposures by the Bayesian kernel machine regression (BKMR). Among women, we found positive linear relationships between urinary Mn with FPG (P_overall = 0.003, P_nonlinear = 0.817) and HbA1c (P_overall = 0.023, P_nonlinear = 0.854). Among men, J-shaped relationships were observed between blood Mn with HOMA-IR (P_nonlinear = 0.042) and insulin (P_nonlinear = 0.014). For eGFR, positive linear relationships were obserned among women for blood Mn (P_nonlinear = 0.549) and among both men and women for urinary Mn levels. The joint-effects of urinary Mn with molybdenum (Mo) on FPG and HbA1c, urinary Mn with cadmium (Cd) and cesium (Cs) on eGFR, and blood Mn with Cd and lead (Pb) on eGFR were detected. In summary, blood and urinary Mn levels were independently associated with glucose levels, insulin resistance and kidney function with potential sex-dependent heterogeneities. These findings emphasize the probable role of Mn in the regulation of glucose metabolism and kidney function, and confirm the need for more studies on sex-specific risk of diabetes.

Role of Minerals and Trace Elements in Diabetes and Insulin Resistance

Minerals and trace elements are micronutrients that are essential to the human body but present only in traceable amounts. Nonetheless, they exhibit well-defined biochemical functions. Deficiencies in these micronutrients are related to widespread human health problems. This review article is focused on some of these minerals and trace element deficiencies and their consequences in diabetes and insulin resistance. The levels of trace elements vary considerably among different populations, contingent on the composition of the diet. In several Asian countries, large proportions of the population are affected by a number of micronutrient deficiencies. Local differences in selenium, zinc, copper, iron, chromium and iodine in the diet occur in both developed and developing countries, largely due to malnutrition and dependence on indigenous nutrition. These overall deficiencies and, in a few cases, excess of essential trace elements may lead to imbalances in glucose homeostasis and insulin resistance. The most extensive problems affecting one billion people or more worldwide are associated with inadequate supply of a number of minerals and trace elements including iodine, selenium, zinc, calcium, chromium, cobalt, iron, boron and magnesium. This review comprises various randomized controlled trials, cohort and case-controlled studies, and observational and laboratory-based studies with substantial outcomes of micronutrient deficiencies on diabetes and insulin resistance in diverse racial inhabitants from parts of Asia, Africa, and North America. Changes in these micronutrient levels in the serum and urine of subjects may indicate the trajectory toward metabolic changes, oxidative stress and provide disease-relevant information.

Dual Anti-/Prooxidant Behaviors of Flavonoids Pertaining to Cu(II)-Catalyzed Tyrosine Nitration of the Insulin Receptor Kinase Domain in an Antidiabetic Study

Flavonoid, as a potent antioxidant, exerts many beneficial effects in type 2 diabetes, whereas the prooxidative property may be also important in vivo if copper is involved. Here, we chose an insulin receptor kinase domain fragment (KK-1, residues 1126-1165), containing the A-loop of the receptor as well as three key autophosphorylation sites (Tyr¹¹⁵⁸, Tyr¹¹⁶², and Tyr¹¹⁶³) associated with receptor signal transduction to investigate the roles and the structure-activity relationship of three antidiabetic flavonoids (kaempferol, luteolin, and apigenin) and two others with a similar structure (diosmetin and genistein), on modulation of Cu(II)-mediated tyrosine nitration and the corresponding effect on its functional phosphorylation in the Cu²⁺/H₂O₂/NO₂^- system. We found that both properties of flavonoid played roles on inhibition of Cu(II)-mediated protein nitration in the H₂O₂/NO₂^- system: (1) on the one hand, flavonoid scavenged free radicals as antioxidants, inhibited tyrosine nitration, and thus inhibited the reduction of tyrosine phosphorylation caused by tyrosine nitration; and (2) on the other hand, flavonoid promoted ^•OH production as a prooxidant, which increased 3,3'-dityrosine formation. The formation of 3,3'-dityrosine decreased Cu²⁺-induced tyrosine nitration and thus interfered with its phosphorylation. This study confirms that the weight relationship between antioxidation and prooxidation of a flavonoid needs to be studied clearly before nutritional and medical applications.

Aluminum Exposure and Gestational Diabetes Mellitus: Associations and Potential Mediation by n-6 Polyunsaturated Fatty Acids

As the earth's third most abundant element with various industrial applications, aluminum (Al) has received increasing concerns over its potential adverse health effects. Although Al exposure has been suggested to increase the risks of type 2 diabetes, little has been done to explore Al exposure in pregnant women and potential impact on the incidence of gestational diabetes mellitus (GDM). Our present study demonstrated positive associations between Al concentrations in maternal plasma collected in the first trimester of pregnancy and GDM risks (P_trend < 0.001) based on a nested case-control study from Wuhan, China, including 305 GDM cases and 305 healthy controls. The highest tertile of plasma Al concentrations corresponded to an odds ratio of 4.03 (95% confidence interval: [2.14, 7.58]) relative to the lowest tertile, after the adjustment for established GDM risk factors and other plasma metals. We also observed significant correlations between plasma Al and several plasma polyunsaturated fatty acids (PUFA; e.g., linoleic acid 18:2 n-6) levels. In addition, mediation effects on the associations of Al exposure with GDM risks were observed for n-6 PUFAs (estimated mediation percentage: 48.3%) and total PUFAs (48.9%). Our study is not only by far the largest study of its kind to demonstrate maternal Al exposure and the association with GDM risks, but it also offers an insight into the potential mediation roles of n-6 PUFAs in an epidemiological setting. These findings contribute to a better understanding of perinatal Al exposure and GDM risks.

Site-Specific Interactions with Copper Promote Amyloid Fibril Formation for λ6aJL2-R24G

Light-chain amyloidosis (AL) is one of the most common systemic amyloidoses, and it is characterized by the deposition of immunoglobulin light chain (LC) variable domains as insoluble amyloid fibers in vital organs and tissues. The recombinant protein 6aJL2-R24G contains λ6a and JL2 germline genes and also contains the Arg24 by Gly substitution. This mutation is present in 25% of all amyloid-associated λ6 LC cases, reduces protein stability, and increases the propensity to form amyloid fibers. In this study, it was found that the interaction of 6aJL2-R24G with Cu(II) decreases the thermal stability of the protein and accelerates the amyloid fibril formation, as observed by fluorescence spectroscopy. Isothermal calorimetry titration showed that Cu(II) binds to the protein with micromolar affinity. His99 may be one of the main Cu(II) interaction sites, as observed by nuclear magnetic resonance spectroscopy. The binding of Cu(II) to His99 induces larger fluctuations of the CDR1 and loop C″, as shown by molecular dynamics simulations. Thus, Cu(II) binding may be inducing the loss of interactions between CDR3 and CDR1, making the protein less stable and more prone to form amyloid fibers. This study provides insights into the mechanism of metal-induced aggregation of the 6aJL2-R24G protein and sheds light on the bio-inorganic understanding of AL disease.

Antagonist biocompatibilities of Zn-based materials functionalized with physiological active metal oxides

Zinc coated with nanostructured ZnO flowers has received increasing attention as a versatile biomaterial for medical applications. Whatsoever, the potential of these materials to meet specific medical requirements must be explored. Despite in its infancy, surface functionalization is the key strategy to achieve this goal. The functionalization, successfully achieved with cooper (Cu), iron (Fe) or manganese (Mn) oxides (Ox), was highly dependent on the presence of the flowered structures, with the deep physicochemical characterization of these new surfaces revealing specific metal oxide distributions. The functionalization with these metal oxides resulted in distinct biological and in vitro behaviours. The biological response, assessed by fibroblast viability, hemocompatibility, and chick chorioallantoic membrane (CAM), further supported by the in vitro degradation studies, evaluated by immersion and electrochemical techniques, revealed that the deleterious role of CuOx functionalization brought potential for anti-cancer applications; with an antagonist behaviour, the functionalization with MnOx, and in a less extent with FeOx, can be used to favour wound healing in traumatic processes. Despite the possible correlation between biocompatibility and hydroxyapatite precipitation, no correlation could be drawn with the corrosion activity of these surfaces. Overall, the minor addition of relevant physiological as Cu, Fe or Mn oxides resulted in antagonist in vitro responses that can be used as expedite strategies to modulate the behaviour of Zn-based materials, contributing in this way for the design of anti-cancer or wound healing therapies.

Serum Selenium and Lead Levels: a Possible Link with Diabetes and Associated Proteinuria

The study assessed trace element selenium (Se) and a heavy metal lead (Pb) in patients with type II diabetes mellitus (T2DM) and its associated proteinuria. Total 275 subjects aged between 30 and 90 years were studied: 93 T2DM, 98 T2DM with proteinuria, and 84 as controls. Serum Se and Pb were analyzed by inductively coupled plasma optical emission spectrometer (ICP-OES) and other biochemical indices by ROCHE module COBAS 6000 analyzer. Statistical analysis was done by one-way analysis of variance (ANOVA) at P < 0.0001 followed by Tukey's honest test. Pearson's correlation coefficient was applied to observe the effects of Se and Pb on FPG and ACR. Decreased Se levels were observed in T2DM and T2DM with proteinuria with no significant difference and serum Pb was found within reference range in both groups. Se showed no significant association with FBG and ACR while mid-upper tertile of Pb was significantly associated with ACR of T2DM with the proteinuria group (P < 0.01). Se is known to have a U-shaped relationship with T2DM. Low Se levels in both groups may be due to the effect of disease and its related inflammation. Detected levels of Pb suggest that studied population had lower exposure to it. Association of Pb with ACR showed consistency with the classical studies that even low levels of Pb may cause the renal deterioration.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Cadmium exposure induces pancreatic β-cell death via a Ca2+-triggered JNK/CHOP-related apoptotic signaling pathway

Cadmium (Cd) is known to be ranked the 7^th hazardous substance in the Substance Priority List by Agency for Toxic Substances and Disease Registry. The experimental and epidemiological data have suggested that Cd is linked to the development of diabetes mellitus (DM). The molecular mechanism of Cd on the pancreatic β-cell cytotoxicity still remains unclear. Evidence has pointed toward that Ca²⁺ is an important regulator of toxic insult-induced β-cell cytotoxicity. The role of Ca²⁺ in the Cd-induced β-cell cytotoxicity is still unknown. In this study, we found that Cd exposure significantly inhibited insulin secretion and cell viability in the pancreatic β-cell-derived RIN-m5F cells. Cd exposure induced apoptotic events, including the increased populations of apoptotic cells and sub-G1 hypodiploid cells, and caspase-3/-7/-9 and poly (ADP-ribose) polymerase (PARP) activation, which largely depended on the activation of c-Jun N-terminal kinase (JNK) and C/EBP homologous protein (CHOP). Transfection with siRNAs for JNK and CHOP or pretreatment with specific pharmacological inhibitor of JNK (SP600125) in β-cells effectively prevented the Cd-induced insulin secretion dysfunction and apoptosis. JNK-specific siRNA dramatically suppressed Cd-induced JNK phosphorylation and CHOP protein expression, but JNK phosphorylation could not be inhibited by CHOP-specific siRNA. Furthermore, Cd exposure significantly increased the intracellular calcium ([Ca²⁺]_i) levels. Buffering the Ca²⁺ response with BAPTA/AM effectively abrogated the Cd-induced [Ca²⁺]_i elevation, insulin secretion dysfunction, apoptosis, and protein expression of JNK phosphorylation and CHOP activation. Taken together, these findings demonstrated that Cd exposure exerts β-cell death via a [Ca²⁺]_i-dependent JNK activation-activated downstream CHOP-related apoptotic signaling pathway.

Comparison of Chromium and Iron Distribution in Serum and Urine among Healthy People and Prediabetes and Diabetes Patients

The effect of chromium (Cr) and iron (Fe) on prevalence of diabetes has received great attention. This study investigated serum and urinary Cr and Fe levels among patients with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), type 1 diabetes (T1D), and type 2 diabetes (T2D) in the Northeast Chinese population. From January 2010 to October 2011, patients with IFG (n=12), IGT (n=15), T1D (n=25), T2D (n=137) and healthy controls (n=50) were enrolled in the First Hospital of Jilin University. Trace elements were detected using an inductively coupled plasma spectrometer. Serum Cr levels decreased in T2D without complications, diabetic retinopathy (DR), diabetic peripheral neuropathy (DPN), and diabetic nephropathy (DN) (P<0.05). The urinary Cr level in T1D was the highest of all, which significantly exceeded those of the T2D groups with and without complications. No significant differences of serum Fe levels were found among all groups. The urinary Fe level of T1D was significantly increased (P<0.05). The correlation between serum Cr and serum Fe in T2D was obviously positive (P<0.05). One month of simvastatin therapy exerted no effects on serum or urinary Cr and Fe levels. These results suggest the potential role of Cr and Fe in diabetes should receive attention.

Urban and rural area differences in the interaction between oxidative process elements in human femoral bone

Elements in the human body come from contaminated food, water, and air from the living area. Bones are a marker of long-term exposure to elements and show a relationship between them. The aim of the study was to analyze the correlation between the contents of Zn, Cu, Fe, Mo, Cr, Ni, Ba, Sr, and Pb in the proximal femoral head (cancellous bone) and femoral neck (cortical bone) in rural and urban populations. The study included 96 patients who were operated on for total hip replacement (THR), acquired in a surgical procedure with atomic absorption spectrometry, and the content of Zn, Cu, Fe, Mo, Cr, Ni, Ba, Sr, and Pb was evaluated. In rural areas, significant negative correlations were observed for Mo/Cr, Mo/Cu, and Ni/Fe, and positive correlations were observed for Fe/Zn and Pb/Zn. In urban areas, a negative correlation was found for Pb/Mo. Pb and Ni increased with age only in villagers, and Zn and Sr decreased with age in urban citizens. Ba decreased with age in people from rural areas. The correlation showed variances mainly in molybdenum, nickel, and oxidative elements between rural and urban populations.

The NOAEL Metformin Dose Is Ineffective against Metabolic Disruption Induced by Chronic Cadmium Exposure in Wistar Rats

Previous studies have proposed that cadmium (Cd) is a metabolic disruptor, which is associated with insulin resistance, metabolic syndrome, and diabetes. This metal is not considered by international agencies for the study of metabolic diseases. In this study, we investigate the effect of metformin on Cd-exposed Wistar rats at a lowest-observed-adverse-effect level (LOAEL) dose (32.5 ppm) in drinking water. Metabolic complications in the rats exposed to Cd were dysglycemia, insulin resistance, dyslipidemia, dyslipoproteinemia, and imbalance in triglyceride and glycogen storage in the liver, muscle, heart, kidney, and adipose tissue. Meanwhile, rats treated orally with a No-observable-adverse-effect level (NOAEL) dose of metformin (200 mg/kg/day) showed mild improvement on serum lipids, but not on glucose tolerance; in tissues, glycogen storage was improved, but lipid storage was ineffective. In conclusion, metformin as a first-line pharmacological therapy must take into consideration the origin and duration of metabolic disruption, because in this work the NOAEL dose of metformin (200 mg/kg/day) showed a limited efficiency in the metabolic disruption caused by chronic Cd exposure.

The Essential Element Manganese, Oxidative Stress, and Metabolic Diseases: Links and Interactions

Manganese (Mn) is an essential element that is involved in the synthesis and activation of many enzymes and in the regulation of the metabolism of glucose and lipids in humans. In addition, Mn is one of the required components for Mn superoxide dismutase (MnSOD) that is mainly responsible for scavenging reactive oxygen species (ROS) in mitochondrial oxidative stress. Both Mn deficiency and intoxication are associated with adverse metabolic and neuropsychiatric effects. Over the past few decades, the prevalence of metabolic diseases, including type 2 diabetes mellitus (T2MD), obesity, insulin resistance, atherosclerosis, hyperlipidemia, nonalcoholic fatty liver disease (NAFLD), and hepatic steatosis, has increased dramatically. Previous studies have found that ROS generation, oxidative stress, and inflammation are critical for the pathogenesis of metabolic diseases. In addition, deficiency in dietary Mn as well as excessive Mn exposure could increase ROS generation and result in further oxidative stress. However, the relationship between Mn and metabolic diseases is not clear. In this review, we provide insights into the role Mn plays in the prevention and development of metabolic diseases.

Trace Elements and Healthcare: A Bioinformatics Perspective

Biological trace elements are essential for human health. Imbalance in trace element metabolism and homeostasis may play an important role in a variety of diseases and disorders. While the majority of previous researches focused on experimental verification of genes involved in trace element metabolism and those encoding trace element-dependent proteins, bioinformatics study on trace elements is relatively rare and still at the starting stage. This chapter offers an overview of recent progress in bioinformatics analyses of trace element utilization, metabolism, and function, especially comparative genomics of several important metals. The relationship between individual elements and several diseases based on recent large-scale systematic studies such as genome-wide association studies and case-control studies is discussed. Lastly, developments of ionomics and its recent application in human health are also introduced.

Diabetes and Alzheimer's Disease: Can Elevated Free Copper Predict the Risk of the Disease?

Background: Defective copper regulation, primarily referred to as chelatable redox active Cu(II), has been involved in the etiology of diabetes, and Alzheimer’s disease (AD).

Objectives: However, no study has determined levels of labile copper non-bound to ceruloplasmin (non-Cp Cu, also known as ‘free’ copper) in the blood of subjects with diabetes compared with that of AD patients.

Methods: To this aim, values of non-Cp Cu were measured in 25 Type 1 (T1D) and 31 Type 2 (T2D) subjects and in28 healthy controls, along with measurements of C-reactive protein, glycated hemoglobin A_1c, cholesterol, and triglycerides. Non-Cp Cu levels were compared with those of an AD group previously studied.

Results: T2D subjects had significantly higher non-Cp Cu levels than Controls and T1D subjects (both p < 0.001 after adjusting for age, sex, and body mass index). A multinomial logistic model revealed that a one unit standard deviation increase of non-Cp Cu increased the relative risk of having T2D by 9.64 with respect to Controls (95% CI: 2.86–32.47). The comparison of non-Cp Cu levels in T2D with those of an AD population previously studied shows rising blood non-Cp Cu copper levels from Controls to T2D and AD.

Conclusion: These results suggest the involvement of catalytically-active Cu(II) and glucose dysregulation in oxidative stress reactions leading to tissue damage in both diseases.

Models for aerobic carbon monoxide dehydrogenase: synthesis, characterization and reactivity of paramagnetic MoVO(μ-S)CuI complexes

Complexes exhibiting the Mo^VO(μ-S)Cu^I cores, EPR properties, electronic structures and biomimetic reactions of aerobic Mo/Cu-containing carbon monoxide dehydrogenases are reported.

Reaction of [CoCp₂][Tp^iPrMoOS(OAr)] [Cp = η⁵-cyclopentadienyl; Tp^iPr = hydrotris(3-isopropylpyrazol-1-yl)borate; OAr = phenolate or derivative thereof] with [Cu(NCMe)(Me₃tcn)]BF₄ (Me₃tcn = 1,4,7-trimethyl-1,4,7-triazacyclononane) in MeCN at –30 °C results in the formation of red-brown/black, paramagnetic, μ-sulfido-Mo(v)/Cu(i) complexes, Tp^iPrMoO(OAr)(μ-S)Cu(Me₃tcn). The complexes possess the MoO(μ-S)Cu core found in aerobic carbon monoxide dehydrogenases (CODHs) and exhibit X-band EPR spectra closely related to those of semi-reduced CODH, with g_iso ∼ 1.937, hyperfine coupling to ^95,97Mo (a_iso = 39–42 × 10^–4 cm^–1) and strong superhyperfine coupling to ^63,65Cu (a_iso = 34–63 × 10^–4 cm^–1). Anisotropic spectra exhibit monoclinic symmetry with g₁ ∼ 1.996, g₂ ∼ 1.944 and g₃ ∼ 1.882, and nearly isotropic A_Cu values (75–90 × 10^–4 cm^–1). The X-ray structures of four derivatives (Ar = Ph, C₆H₄^tBu-2, C₆H₄^sBu-2, C₆H₄Ph-4) are reported and discussed along with that of the Ar = C₆H₃^tBu₂-3,5 derivative (communicated in C. Gourlay, D. J. Nielsen, J. M. White, S. Z. Knottenbelt, M. L. Kirk and C. G. Young, J. Am. Chem. Soc., 2006, 128, 2164). The complexes exhibit distorted octahedral oxo-Mo(v) and distorted tetrahedral Cu(i) centres bridged by a single bent μ-sulfido ligand, with Mo–S and Cu–S distances and Mo–S–Cu angles in the ranges 2.262–2.300 Å, 2.111–2.134 Å and 115.87–134.27°, respectively. The 2 t-butyl derivative adopts a unique phenolate conformation with O Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> Mo–O–Cα and O Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> Mo–S–Cu torsion angles of 92.7 and 21.1°, respectively, very different from those of the other structurally characterized derivatives (31–47 and 33–45°, respectively) and exhibits a relatively short Mo···Cu distance [3.752(2) Å vs. 3.806(7)–4.040(2) Å]. As well, the a_Cu value of this complex (34.3 × 10^–4 cm^–1) is much lower than the values observed for other members of the series (55–63 × 10^–4 cm^–1), supporting the hypothesis that the electronic structure of the MoO(μ-S)Cu core unit and the degree of intermetallic communication are strongly dependent on the geometry of the MoO(OR)(μ-S)Cu unit. The complexes participate in an electrochemically reversible Mo(vi)/Mo(v) redox couple and react with cyanide undergoing decupration and desulfurization reactions of the type observed for CODH.

Trace element status in type 2 diabetes: A meta-analysis

Introduction

Type 2 diabetes is a chronic metabolic disorder that has been associated with alterations in the status of trace elements, including zinc, copper, iron and manganese. However, clinical studies reporting statuses of these trace elements in type 2 diabetes patients compared to controls have shown conflicting results.

Objective

This meta-analysis aimed to summarize the existing literature on the statuses of zinc, copper, iron, and manganese in Type 2 diabetes mellitus patients.

Methods

A literature search of Embase, PubMed, EBSCOHost, ScienceDirect, Scopus, Cochrane library and Web of Science electronic databases was conducted to find studies published from 1970 to November 2016 that compared the trace elements of interest between type 2 diabetic patients and healthy controls. Keywords used were type 2 diabetes, diabetes, hyperglycemia, insulin, glucose, HbA1c, trace elements, micronutrients, zinc, manganese, copper, ceruloplasmin, iron and ferritin. The bias corrected Hedges' g, was utilized as the effect sizes. Due to the biological interaction between trace elements, it is important to collectively evaluate the statuses of these minerals in type 2 diabetes. Thus, the robust variance estimation method was chosen to handle dependency between multiple outcomes.

Results

A total of 52 studies met the inclusion criteria, amounting to 98 effect sizes. Diabetic patients (n=20183) had significantly lower zinc status when compared to controls (effect size = -1.73, p<0.01); whereas copper (effect size = 1.10, p<0.05) and ferritin levels (effect size = 1.05, p<0.01) were significantly higher. Although not significant, ceruloplasmin (effect size = 1.85, p=0.06) and iron (effect size = 1.42, p=0.06) levels were higher, and manganese (effect size = 0.27, p=0.34) was lower in patients.

Conclusion

Results from this meta-analysis indicate lower zinc status accompanied by increased copper and ferritin levels in patients with type 2 diabetes when compared to controls.