Zinc, copper, and oxysterol levels in patients with type 1 and type 2 diabetes mellitus

Copper metabolism and its role in diabetic complications: A review

Disturbances in copper (Cu) homeostasis have been observed in diabetes and associated complications. Cu is an essential micronutrient that plays important roles in various fundamental biological processes. For example, diabetic cardiomyopathy is associated with elevated levels of Cu in the serum and tissues. Therefore, targeting Cu may be a novel treatment strategy for diabetic complications. This review provides an overview of physiological Cu metabolism and homeostasis, followed by a discussion of Cu metabolism disorders observed during the occurrence and progression of diabetic complications. Finally, we discuss the recent therapeutic advances in the use of Cu coordination complexes as treatments for diabetic complications and their potential mechanisms of action. This review contributes to a complete understanding of the role of Cu in diabetic complications and demonstrates the broad application prospects of Cu-coordinated compounds as potential therapeutic agents.

Molecular mechanism of renal lipid accumulation in diabetic kidney disease

Diabetic kidney disease (DKD) is a leading cause of end stage renal disease with unmet clinical demands for treatment. Lipids are essential for cell survival; however, renal cells have limited capability to metabolize overloaded lipids. Dyslipidaemia is common in DKD patients and renal ectopic lipid accumulation is associated with disease progression. Unveiling the molecular mechanism involved in renal lipid regulation is crucial for exploring potential therapeutic targets. In this review, we focused on the mechanism underlying cholesterol, oxysterol and fatty acid metabolism disorder in the context of DKD. Specific regulators of lipid accumulation in different kidney compartment and TREM2 macrophages, a lipid-related macrophages in DKD, were discussed. The role of sodium-glucose transporter 2 inhibitors in improving renal lipid accumulation was summarized.

The association between serum copper concentration and prevalence of diabetes among US adults with hypertension (NHANES 2011-2016)

The objective of this study was to examine the association between the serum copper concentration and the prevalence of diabetes among US adults with hypertension using the data from the National Health and Nutrition Examination Survey (NHANES). The study population was selected from adults aged over 20 years old in the three survey cycles of NHANES from 2011 to 2016. Logistic regression model analyses were applied to determine the independent risky effect of copper to the prevalence of diabetes. Also, a restricted cubic spline (RCS) model was performed to explore the potential nonlinear association between serum copper concentration and the prevalence of diabetes. A total of 1786 subjects (742 cases and 1044 controls) were included, and 924 were men (51.7%), and 742 (41.5%) were diabetic. Compared with non-diabetic individuals, the concentration of serum copper in diabetic patients with hypertension was higher. After adjusting for age, sex, race, education, marital status, body mass index (BMI), family poverty income ratio (PIR), smoking, alcohol drinking, physical activity, systolic blood pressure (SBP), diastolic blood pressure (DBP), and hyperlipidemia, the highest quartile of serum copper concentration significantly increased the risk of diabetes as compared with the lowest quartile (OR: 1.38, 95% CI: 1.01-1.92, ptrend = 0.036). The results of RCS analysis showed significant non-linear relationship between serum copper concentration and prevalence of diabetes (p-non-linear = 0.010). This study finds that serum copper concentration are significantly associated with risk of diabetes in hypertensive patients, which suggests copper as an important risk factor of diabetes development.

Dry and wet experiments reveal diagnostic clustering and immune landscapes of cuproptosis patterns in patients with ankylosing spondylitis

Cuproptosis is a new manner of mitochondrial cell death induced by copper. There is evidence that serum copper has a crucial impact on ankylosing spondylitis (AS) by copper-induced inflammatory response. However, the molecular mechanisms of cuproptosis modulators in AS remain unknown. We aimed to use a bioinformatics-based method to comprehensively investigate cuproptosis-related subtype identification and immune microenvironment infiltration of AS. Additionally, we further verified the results by in vitro experiments, in which peripheral blood and fibroblast cells from AS patients were used to evaluate the functions of significant cuproptosis modulators on AS. Finally, eight significant cuproptosis modulators were identified by analysis of differences between controls and AS cases from GSE73754 dataset. Eight prognostic cuproptosis modulators (LIPT1, DLD, PDHA1, PDHB, SLC31A1, ATP7A, MTF1, CDKN2A) were identified using a random forest model for prediction of AS risk. A nomogram model of the 8 prognostic cuproptosis modulators was then constructed; the model could be beneficial in clinical settings, as indicated by decision curve analysis. Consensus clustering analysis was used to divide AS patients into two cuproptosis subtypes (clusterA & B) according to significant cuproptosis modulators. The cuproptosis score of each sample was calculated by principal component analysis to quantify cuproptosis subtypes. The cuproptosis scores were higher in clusterB than in clusterA. Additionally, cases in clusterA were closely associated with the immunity of activated B cells, Activated CD4 T cell, Type17 T helper cell and Type2 T helper cell, while cases in clusterB were linked to Mast cell, Neutrophil, Plasmacytoid dendritic cell immunity, indicating that clusterB may be more correlated with AS. Notably, key cuproptosis genes including ATP7A, MTF1, SLC31A1 detected by RT-qPCR with peripheral blood exhibited significantly higher expression levels in AS cases than controls; LIPT1 showed the opposite results; High MTF1 expression is correlated with increased osteogenic capacity. In general, this study of cuproptosis patterns may provide promising biomarkers and immunotherapeutic strategies for future AS treatment.

Occurrence, distribution, source apportionment, ecological and health risk assessment of heavy metals in water, sediment, fish and prawn from Ojo River in Lagos, Nigeria

The study investigates the occurrence and bioaccumulation of heavy metals in water, sediment, fish, and prawn from the Ojo River with a view to identify the source of origin and the associated ecological and human health risks. The result shows that heavy metal concentrations in water [As = 0.010, Cd = 0.001, Cr = 0.041, Cu = 0.019, Co = 0.050, Fe = 0.099, Pb = 0.006, Ni = 0.003, and Zn = 0.452(mg/L)] were within the acceptable limits. The heavy metals in the sediment [As = 0.050, Cd = 0.287, Cr = 0.509, Cu = 0.207, Co = 0.086, Fe = 33.093, Pb = 0.548, Ni = 0.153 and Zn = 4.249 (mg/kg)] were within their respective background levels or earth's crust and the TEL and PEL standard limits. The bioaccumulation of heavy metals in fish and prawn tissues are in this hierarchical form: Fe > Zn > Cu > Cr > Ni > Co > Pb > Ar > Cd and Fe > Zn > Cu > Cr > Pb > Ar > Ni > Co > Cd, respectively. The bioaccumulation factors of heavy metals in fish ranged from 0.893 - 16.611 and 1.056 - 49.204 in prawn, which were higher than the biota-sedimentation factors (BSAF) values, inferring that the fish and prawns of this study ingested heavy metals highly from water column. The aggregated BSAF scores (fish = 5.584 and prawn = 9.137) showed that these organisms are good concentrators of heavy metals in sediments. The water quality index and other pollution indices (Single pollution index, Heavy metal assessment index, and Heavy metal pollution index) demonstrates slightly clean water, with a moderate level of contamination. The HI values of heavy metals in water, fish, and prawn were lower than 1, implying non-carcinogenic risk in children or adults. The ADD and EDI values of the metals were within their respective oral reference doses (RfD). The TCR values showed that exposure to water, either by ingestion or dermal absorption and the consumption of P. obscura and M. vollenhovenii from the Ojo River would not induce cancer risks in people, though As, Cr, Cd, and Pb showed carcinogenic potentials. The sediment contamination indices such as CF, mCd, EF, and Igeo showed a moderate level of pollution. The ecological risk values (NMPI, mCd = 0.068, PLI = 0.016, and R.I = 86.651) of heavy metals implies "no-moderate risk" except for Cd, which showed high risk. The ecotoxicological parameters,  m-PEL-Q (0.024) and m-ERM-Q (0.016) denotes low contamination and no probability of acute toxicity. The CV analysis showed high dispersions and variabilities in the distributions of the heavy metals in water. Other source analyses (Pearson's correlation matrix, PCA, and HCA) showed that both natural processes and anthropogenic activities are responsible for the occurrence of heavy metals in water and sediment from the Ojo River.

Impact of Oxysterols in Age-Related Disorders and Strategies to Alleviate Adverse Effects

Oxysterols or cholesterol oxidation products are a class of molecules with the sterol moiety, derived from oxidative reaction of cholesterol through enzymatic and non-enzymatic processes. They are widely reported in animal-origin foods and prove significant involvement in the regulation of cholesterol homeostasis, lipid transport, cellular signaling, and other physiological processes. Reports of oxysterol-mediated cytotoxicity are in abundance and thus consequently implicated in several age-related and lifestyle disorders such as cardiovascular diseases, bone disorders, pancreatic disorders, age-related macular degeneration, cataract, neurodegenerative disorders such as Alzheimer's and Parkinson's disease, and some types of cancers. In this chapter, we attempt to review a selection of physiologically relevant oxysterols, with a focus on their formation, properties, and roles in health and disease, while also delving into the potential of natural and synthetic molecules along with bacterial enzymes for mitigating oxysterol-mediated cell damage.

Oxysterols in Vascular Cells and Role in Atherosclerosis

Atherosclerosis is a major cardiovascular complication of diseases associated with elevated oxidative stress such as type 2 diabetes and metabolic syndrome. In these situations, low-density lipoproteins (LDL) undergo oxidation. Oxidized LDL displays proatherogenic activities through multiple and complex mechanisms which lead to dysfunctions of vascular cells (endothelial cells, smooth muscle cells, and macrophages). Oxidized LDLs are enriched in oxidized products of cholesterol called oxysterols formed either by autoxidation, enzymatically, or by both mechanisms. Several oxysterols have been shown to accumulate in atheroma plaques and to play a key role in atherogenesis. Depending on the type of oxysterols, various biological effects are exerted on vascular cells to regulate the formation of macrophage foam cells, endothelial integrity, adhesion and transmigration of monocytes, plaque progression, and instability. Most of these effects are linked to the ability of oxysterols to induce cellular oxidative stress and cytotoxicity mainly through apoptosis and proinflammatory mediators. Like for excess cholesterol, high-density lipoproteins (HDL) can exert antiatherogenic activity by stimulating the efflux of oxysterols that have accumulated in foamy macrophages.

Role of Oxysterols in Ocular Degeneration Mechanisms and Involvement of P2X7 Receptor

Ocular degeneration, including cataracts, glaucoma, macular degeneration, and diabetic retinopathy, is a major public health challenge, as it affects the quality of life of millions of people worldwide and, in its advanced stages, leads to blindness. Ocular degeneration, although it can affect different parts of the eye, shares common characteristics such as oxysterols and the P2X7 receptor. Indeed, oxysterols, which are cholesterol derivatives, are associated with ocular degeneration pathogenesis and trigger inflammation and cell death pathways. Activation of the P2X7 receptor is also linked to ocular degeneration and triggers the same pathways. In age-related macular degeneration, these two key players have been associated, but further studies are needed to extrapolate this interrelationship to other ocular degenerations.

Unravelling diagnostic clusters and immune landscapes of cuproptosis patterns in intervertebral disc degeneration through dry and wet experiments

Cuproptosis is a manner of mitochondrial cell death induced by copper. However, cuproptosis modulators' molecular processes in intervertebral disc degeneration (IDD) are still unclear. To better understand the processes of cuproptosis regulators in IDD, a thorough analysis of cuproptosis regulators in the diagnostic biomarkers and subtype determination of IDD was conducted. Then we collected clinical IDD samples and successfully established IDD model in vivo and in vitro, and carried out real-time quantitative polymerase chain reaction (RT-qPCR) validation of significant cuproptosis modulators. Totally we identified 8 crucial cuproptosis regulators in the present research. Using a random forest model, we isolated 8 diagnostic cuproptosis modulators for the prediction of IDD risk. Then, based on our following decision curve analysis, we selected the five diagnostic cuproptosis regulators with importance scores greater than two and built a nomogram model. Using a consensus clustering method, we divided IDD patients into two cuproptosis clusters (clusterA and clusterB) based on the important cuproptosis regulators. Additionally, each sample's cuproptosis value was evaluated using principal component analysis in order to quantify the cuproptosis clusters. Patients in clusterB had higher cuproptosis scores than patients in clusterA. Moreover, we found that clusterB was involved in the immunity of natural killer cell, while clusterA was related to activated CD4 T cell, activated B cell, etc. Notably, cuproptosis modulators detected by RT-qPCR showed generally consistent expression levels with the bioinformatics results. To sum up, cuproptosis modulators play a crucial role in the pathogenic process of IDD, providing biomarkers and immunotherapeutic approaches for IDD.

Glycemic variability leads to higher levels of auto-oxidized oxysterol species in patients with type 1 diabetes mellitus

PURPOSE

Hyperglycemia and glycemic variability (GV) are associated with oxidative stress in patients with diabetes mellitus (DM). Oxysterol species, produced by the non-enzymatic oxidation of cholesterol, are potential biomarkers of oxidative stress. This study examined the relationship between auto-oxidized oxysterols and GV in patients with type 1 DM.

METHODS

Thirty patients with type 1 DM using a continuous subcutaneous insulin infusion pump therapy and a healthy control group (n = 30) were included in this prospective study. A Continuous Glucose Monitoring System device was applied for 72 h. Blood samples were taken for oxysterols produced by non-enzymatic oxidation [7-ketocholesterol (7-KC) and cholestane-3β, 5α, 6β-triol (Chol-Triol)] levels at 72 h. Short-term glycemic variability parameters, mean amplitude of glycemic excursions (MAGE), the standard deviation of glucose measurements (Glucose-SD), and mean of daily differences (MODD) were calculated with continuous glucose monitoring data. HbA1c was used to evaluate glycemic control and HbA1c-SD (the SD of HbA1c over the past year) for long-term glycemic variability.

RESULTS

7-KC and Chol-triol levels were significantly higher in the study group than in the control group. Strong positive correlations were found between 7-KC with MAGE(24-48 h) and Glucose-SD(24-48 h). 7-KC was positively correlated with MAGE(0-72 h) and Glucose-SD(0-72 h). No significant correlation was found between HbA1c and HbA1c -SD with oxysterol levels. The regression models showed that SD(24-48 h) and MAGE(24-48 h) predicted 7-KC levels while HbA1c did not.

CONCLUSIONS

Glycemic variability leads to higher levels of auto-oxidized oxysterol species in patients with type 1 DM independent of long-term glycemic control.

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.

Higher concentration of 25-hydroxycholesterol in treatment-naïve patients with type 2 diabetes compared to healthy individuals

BACKGROUND

Oxysterols are cholesterol oxidation derivatives with diverse biological activities. However, little is known about the oxysterol levels in treatment-naïve patients with type 2 diabetes.

OBJECTIVE

We utilized gas chromatography-mass spectrometry to investigate the potential association between oxysterol concentrations and type 2 diabetes and atherosclerosis in treatment-naïve patients diagnosed with type 2 diabetes.

METHODS

This case-control study enrolled 53 eligible patients with type 2 diabetes and 50 healthy volunteers. We compared serum oxysterol concentrations between the two groups; we examined the correlation between the oxysterol concentrations and the carotid plaque score in the type 2 diabetes group.

RESULTS

Univariate analysis revealed significant differences in the concentrations of oxysterols (i.e., cholesterol-5α, 6α-epoxide; cholesterol-5β, 6β-epoxide; 7β-hydroxycholesterol; and 25-hydroxycholesterol [25-HC]) and other cardiovascular risk factors between the two groups. The 25-HC concentration was almost twofold greater in the type 2 diabetes group than in the healthy volunteers (median [interquartile range]: 8.52 [6.37-11.26] vs. 4.58 [3.45-5.44] ng/mL). After adjusting for multiple covariates, such as age, body mass index, mean arterial pressure, and triglyceride, low-density lipoprotein-cholesterol, and high-density lipoprotein-cholesterol levels, only the concentration of 25-HC showed a significant association with type 2 diabetes. However, the univariate analysis failed to demonstrate any significant correlation between oxysterol concentrations and the carotid plaque score among individuals with type 2 diabetes.

CONCLUSIONS

The levels of various oxysterols differ between treatment-naïve patients with type 2 diabetes and healthy individuals; the 25-HC level differs the most prominently.

Metabolic perspective of astrocyte dysfunction in Alzheimer's disease and type 2 diabetes brains

The term type III diabetes (T3DM) has been proposed for Alzheimer's disease (AD) due to the shared molecular and cellular features between type 2 diabetes (T2DM) and insulin resistance-associated memory deficits and cognitive decline in elderly individuals. Astrocytes elicit neuroprotective or deleterious effects in AD progression and severity. Patients with T2DM are at a high risk of cognitive impairment, and targeting astrocytes might be promising in alleviating neurodegeneration in the diabetic brain. Recent studies focusing on cell-specific activities in the brain have revealed the important role of astrocytes in brain metabolism (e.g., glucose metabolism, lipid metabolism), neurovascular coupling, synapses, and synaptic plasticity. In this review, we discuss how astrocytes and their dysfunction result in multiple pathological and clinical features of AD and T2DM from a metabolic perspective and the potential comorbid mechanism in these two diseases from the perspective of astrocytes.

Evaluation among trace elements, clinical parameters and type 1 diabetes according to sex: A new sight of auxiliary prediction in negative insulin auto-antibodies population

BACKGROUND

Type 1 diabetes (T1D) exhibited sex-specific metabolic status including oxidative stress with dynamic change of trace elements, which emphasized the importance of the evaluation of trace elements according to sex. Besides, the most significant characteristic, insulin auto-antibodies, could not be found in all T1D patients, which needed the auxiliary prediction of clinical parameters. And it would benefit the early detection and treatment if some high-risk groups of T1D could predict and prevent the occurrence of disease through common clinical parameters. Hence, there was an urgent need to construct more effective and scientific statistical prediction models to serve clinic better. This study aimed to evaluate the sex-specific levels of trace elements and the relationship between trace elements and clinical parameters in T1D, and construct sex-specific auxiliary prediction model combined with trace elements and clinical parameters.

METHODS

A total of 105 T1D patients with negative insulin auto-antibodies and 105 age/sex-matched healthy individuals were enrolled in First Hospital of Jilin University. Inductively Coupled Plasma Mass Spectrometry was performed for the measurement of calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), iron (Fe), selenium (Se) in the serum, and the data of clinical parameters were received from medical record system. The lambda-mu-sigma method was used to evaluate the relationship between abnormal clinical parameters and trace elements. Training set and validation set were divided for the construction of predictable models in males and females: clinical parameters model, trace element model and the combined model (clinical parameters and trace elements). Goodness fit test, decision curve analysis and other related statistical methods were used to perform data analysis.

RESULTS

Lower levels of Mg, Ca, Fe in the serum were found in T1D population in females compared with healthy population, while levels of Fe, Zn and Cu of serum in T1D individuals were higher than those of healthy population in males. Levels of serum Mg, Fe and Cu in T1D group were found with significant sex difference for (P < 0.05), and the levels of Fe and Cu in serum of males were higher than those of females, level of serum Mg in males was lower than those of females. Levels of serum Mg and Zn showed fluctuation trend with increased numbers of abnormal clinical parameters (NACP) in males. Serum Zn in females showed consistent elevated trend with NACP; serum Se increased first and then decreased with NACP in males and females. The auxiliary prediction model (Triglyceride, Total protein, serum Mg) was found with the highest predicted efficiency in males (AUC=0.993), while the model in females (Apolipoprotein A, Creatinine, Fe, Se, Zn/Cu ratio) showed the best predicted efficiency (AUC=0.951). The models had passed the verification in validation set, and Chi-square goodness-of-fit test, DCA results both confirmed their satisfactory clinical applicability.

CONCLUSION

Sex-specific difference were found in serum Mg, Fe and Cu in T1D. The combination of triglyceride, total protein and serum Mg for males, and apolipoprotein A, creatinine, Fe, Se, Zn/Cu ratio for females could effectively predict T1D in patients with negative anti-bodies, which would provide alarm for the population with high-risk of T1D and serve the T1D prediction in patients with negative anti-bodies.

A cross-sectional study on the effect of dietary zinc intake on the relationship between serum vitamin D3 and HOMA-IR

Introduction

Serum vitamin D₃ concentration is associated with the risk of insulin resistance. Zinc has also been reported to be associated with a lower risk of insulin resistance. In addition, zinc is an essential cofactor in the activation of vitamin D₃. However, the effect of dietary zinc intake on the relationship between vitamin D₃ and insulin resistance risk has not been fully studied. Therefore, we designed this cross-sectional study to assess the impact of changes in zinc intake on the relationship between vitamin D₃ and insulin resistance risk.

Study design and methods

This study analyzed data from the national Health and Nutrition Examination Survey (NHANES) from 2005 to 2018, involving 9,545 participants. Participants were stratified by zinc intake category (low zinc intake <9.58 mg/ day; High zinc intake: ≥9.58 mg/ day).

Results

In this cross-sectional study, serum vitamin D₃ levels were independently associated with the risk of insulin resistance in both the low and high Zinc intakes (β: −0.26, 95%Cl: −0.56~0.04 vs. β: −0.56, 95%Cl: −1.01~-0.11). In addition, this association was influenced by different dietary zinc intakes (interaction P < 0.05).

Conclusions

Our results suggest that zinc intake may influence the association between serum vitamin D₃ and the risk of insulin resistance. Further randomized controlled trials are needed to provide more evidence of this finding.

Air Pollution, Oxidative Stress, and the Risk of Development of Type 1 Diabetes

Despite multiple studies focusing on environmental factors conducive to the development of type 1 diabetes mellitus (T1DM), knowledge about the involvement of long-term exposure to air pollution seems insufficient. The main focus of epidemiological studies is placed on the relationship between exposure to various concentrations of particulate matter (PM): PM1, PM2.5, PM10, and sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (O3), versus the risk of T1DM development. Although the specific molecular mechanism(s) behind the link between increased air pollution exposure and a higher risk of diabetes and metabolic dysfunction is yet unknown, available data indicate air pollution-induced inflammation and oxidative stress as a significant pathway. The purpose of this paper is to assess recent research examining the association between inhalation exposure to PM and associated metals and the increasing rates of T1DM worldwide. The development of modern and more adequate methods for air quality monitoring is also introduced. A particular emphasis on microsensors, mobile and autonomous measuring platforms, satellites, and innovative approaches of IoT, 5G connections, and Block chain technologies are also presented. Reputable databases, including PubMed, Scopus, and Web of Science, were used to search for relevant literature. Eligibility criteria involved recent publication years, particularly publications within the last five years (except for papers presenting a certain novelty or mechanism for the first time). Population, toxicological and epidemiological studies that focused particularly on fine and ultra-fine PM and associated ambient metals, were preferred, as well as full-text publications.

The Association Between Plasma Copper Concentration and Prevalence of Diabetes in Chinese Adults With Hypertension

Objective

The relationship between plasma copper concentration and prevalence of diabetes in adults with hypertension is unclear. We aimed to determine the association between plasma copper concentration and prevalence of diabetes in Chinese adults with hypertension.

Methods

A total of 2,579 participants (697 cases and 1,882 controls) was included in this cross-sectional study. Plasma copper concentrations were determined by inductively coupled plasma mass spectrometry. Multivariable logistic regression model was used to determine the association between plasma copper concentration and prevalence of diabetes.

Results

According to the logistic regression analyses, the adjusted OR for the prevalence of diabetes in participants with plasma copper concentration ≥109.4 μg/dL was 1.26 (1.00, 1.58) compared with those with plasma copper concentration <109.4 μg/dL (P = 0.048). The association was no longer significant following further adjusting for serum high-density lipoprotein cholesterol (HDL-C) concentration as a potential confounder. Stratified analyses demonstrated that serum HDL-C concentration significantly modified the association between plasma copper concentration and prevalence of diabetes (P-interaction = 0.043). In the strata of serum HDL-C concentration ≥1.2 mmol/L, a 56% increased prevalence of diabetes was observed in participants with plasma copper concentration ≥109.4 μg/dL compared with those with plasma copper concentration <109.4 μg/dL (P = 0.008). No significant relationship between plasma copper concentration and prevalence of diabetes was found in other strata.

Conclusion

Our findings suggested that high plasma copper concentration (≥109.4 μg/dL) was associated with increased prevalence of diabetes in Chinese hypertensive adults with serum HDL-C concentration ≥1.2 mmol/L.

Gene-environment interaction analysis of redox-related metals and genetic variants with plasma metabolic patterns in a general population from Spain: The Hortega Study

Background

Limited studies have evaluated the joint influence of redox-related metals and genetic variation on metabolic pathways. We analyzed the association of 11 metals with metabolic patterns, and the interacting role of candidate genetic variants, in 1145 participants from the Hortega Study, a population-based sample from Spain.

Methods

Urine antimony (Sb), arsenic, barium (Ba), cadmium (Cd), chromium (Cr), cobalt (Co), molybdenum (Mo) and vanadium (V), and plasma copper (Cu), selenium (Se) and zinc (Zn) were measured by ICP-MS and AAS, respectively. We summarized 54 plasma metabolites, measured with targeted NMR, by estimating metabolic principal components (mPC). Redox-related SNPs (N = 291) were measured by oligo-ligation assay.

Results

In our study, the association with metabolic principal component (mPC) 1 (reflecting non-essential and essential amino acids, including branched chain, and bacterial co-metabolism versus fatty acids and VLDL subclasses) was positive for Se and Zn, but inverse for Cu, arsenobetaine-corrected arsenic (As) and Sb. The association with mPC2 (reflecting essential amino acids, including aromatic, and bacterial co-metabolism) was inverse for Se, Zn and Cd. The association with mPC3 (reflecting LDL subclasses) was positive for Cu, Se and Zn, but inverse for Co. The association for mPC4 (reflecting HDL subclasses) was positive for Sb, but inverse for plasma Zn. These associations were mainly driven by Cu and Sb for mPC1; Se, Zn and Cd for mPC2; Co, Se and Zn for mPC3; and Zn for mPC4. The most SNP-metal interacting genes were NOX1, GSR, GCLC, AGT and REN. Co and Zn showed the highest number of interactions with genetic variants associated to enriched endocrine, cardiovascular and neurological pathways.

Conclusions

Exposures to Co, Cu, Se, Zn, As, Cd and Sb were associated with several metabolic patterns involved in chronic disease. Carriers of redox-related variants may have differential susceptibility to metabolic alterations associated to excessive exposure to metals.

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In a population-based sample, cobalt, copper, selenium, zinc, arsenic, cadmium and antimony exposures were related to some metabolic patterns.

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Carriers of redox-related variants displayed differential susceptibility to metabolic alterations associated to excessive metal exposures.

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Cobalt and zinc showed a number of statistical interactions with variants from genes sharing biological pathways with a role in chronic diseases.

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The metabolic impact of metals combined with variation in redox-related genes might be large in the population, given metals widespread exposure.

New Function of Cholesterol Oxidation Products Involved in Osteoporosis Pathogenesis

Osteoporosis (OP) is a systemic bone disease characterized by decreased bone strength, microarchitectural changes in bone tissues, and increased risk of fracture. Its occurrence is closely related to various factors such as aging, genetic factors, living habits, and nutritional deficiencies as well as the disturbance of bone homeostasis. The dysregulation of bone metabolism is regarded as one of the key influencing factors causing OP. Cholesterol oxidation products (COPs) are important compounds in the maintenance of bone metabolic homeostasis by participating in several important biological processes such as the differentiation of mesenchymal stem cells, bone formation in osteoblasts, and bone resorption in osteoclasts. The effects of specific COPs on mesenchymal stem cells are mainly manifested by promoting osteoblast genesis and inhibiting adipocyte genesis. This review aims to elucidate the biological roles of COPs in OP development, starting from the molecular mechanisms of OP, pointing out opportunities and challenges in current research, and providing new ideas and perspectives for further studies of OP pathogenesis.

Plasma oxyphytosterols most likely originate from hepatic oxidation and subsequent spill-over in the circulation

We evaluated oxyphytosterol (OPS) concentrations in plasma and various tissues of two genetically modified mouse models with either increased cholesterol (apoE KO mice) or increased cholesterol and plant sterol (PS) concentrations (apoExABCG8 dKO mice). Sixteen female apoE KO and 16 dKO mice followed the same standard, low OPS-chow diet. Animals were euthanized at 36 weeks to measure PS and OPS concentrations in plasma, brain, liver and aortic tissue. Cholesterol and oxysterol (OS) concentrations were analyzed as reference for sterol oxidation in general. Plasma campesterol (24.1 ± 4.3 vs. 11.8 ± 3.0 mg/dL) and sitosterol (67.4 ± 12.7 vs. 4.9 ± 1.1 mg/dL) concentrations were severely elevated in the dKO compared to the apoE KO mice (p < 0.001). Also, in aortic and brain tissue, PS levels were significantly elevated in dKO. However, plasma, aortic and brain OPS concentrations were comparable or even lower in the dKO mice. In contrast, in liver tissue, both PS and OPS concentrations were severely elevated in the dKO compared to apoE KO mice (sum OPS: 7.4 ± 1.6 vs. 4.1 ± 0.8 ng/mg, p < 0.001). OS concentrations followed cholesterol concentrations in plasma and all tissues suggesting ubiquitous oxidation. Despite severely elevated PS concentrations, OPS concentrations were only elevated in liver tissue, suggesting that OPS are primarily formed in the liver and plasma concentrations originate from hepatic spill-over into the circulation.

The Role of Zinc Homeostasis in the Prevention of Diabetes Mellitus and Cardiovascular Diseases

Zinc is an essential micronutrient for human health and is involved in various biological functions, such as growth, metabolism, and immune function. In recent years, research on intracellular zinc dynamics has progressed, and it has become clear that zinc transporters strictly control intracellular zinc localization, zinc regulates the functions of various proteins and signal transduction pathways as a second messenger similar to calcium ions, and intracellular zinc dyshomeostasis is associated with impaired insulin synthesis, secretion, sensitivity, lipid metabolism, and vascular function. Numerous animal and human studies have shown that zinc deficiency may be associated with the risk factors for diabetes and cardiovascular diseases (CVDs) and zinc administration might be beneficial for the prevention and treatment of these diseases. Therefore, an understanding of zinc biology may help the establishment of novel strategies for the prevention and treatment of diabetes and CVDs. This review will summarize the current knowledge on the role of zinc homeostasis in the pathogenesis of diabetes and atherosclerosis and will discuss the potential of zinc in the prevention of these diseases.

Synthesis of Oxidized 3β,3'β-Disteryl Ethers and Search after High-Temperature Treatment of Sterol-Rich Samples

It was proven that sterols subjected to high-temperature treatment can be concatenated, which results in polymeric structures, e.g., 3β,3'β-disteryl ethers. However, it was also proven that due to increased temperature in oxygen-containing conditions, sterols can undergo various oxidation reactions. This study aimed to prove the existence and perform quantitative analysis of oxidized 3β,3'β-disteryl ethers, which could form during high-temperature treatment of sterol-rich samples. Samples were heated at 180, 200 and 220 °C for 0.5 to 4 h. Quantitative analyses of the oxidized 3β,3'β-disteryl ethers were performed with liquid extraction, solid-phase extraction and liquid chromatography coupled with mass spectrometry. Additionally, to perform this analysis, the appropriate standards of all oxidized 3β,3'β-disteryl ethers were prepared. Eighteen various oxidized 3β,3'β-disteryl ethers (derivatives of 3β,3'β-dicholesteryl ether, 3β,3'β-disitosteryl ether and 3β,3'β-distigmasteryl ether) were prepared. Additionally, the influence of metal compounds on the mechanism of ether formation at high temperatures was investigated.

The Association between Zinc and Copper Circulating Levels and Cardiometabolic Risk Factors in Adults: A Study of Qatar Biobank Data

Cardiometabolic risk (CMR) factors increase the likelihood of developing cardiovascular diseases (CVD). In Qatar, 24% of the total deaths are attributed to CVDs. Several nutritional disturbances have been linked to high risk of CVD. Many studies have discussed the effects of zinc (Zn) and copper (Cu) on CMR factors; however, evidence has been controversial. This investigated the association between CMR factors and the status of Zn and Cu, in addition to Zn/Cu ratio. A total of 575 Qatari men and women aged 18 years and older were obtained from Qatar Biobank. Plasma levels of Zn and Cu were determined using inductively coupled plasma mass spectrometry (ICP-MS). Anthropometric data and CMR factors were determined using standard methods. Adjusted associations between trace minerals and CMR were estimated by logistic regression. Partial correlation was performed to test the strength of the associations. Zn was not strongly correlated (p-value ˃ 0.01) or significantly associated with CMR factors and metabolic syndrome (MetS). Cu levels correlated positively with body mass index (BMI) (0.23; p ˂ 0.001), pulse rate (PR) (0.18; p ˂ 0.001), total cholesterol (0.13; p = 0.01), and high-density lipoproteins (HDL) (0.27; p ˂ 0.001); and negatively with diastolic blood pressure (DBP) (−0.13; p = 0.01). High plasma Cu significantly decreased the risk of metabolic syndrome (MetS) (0.121; p ˂ 0.001). Furthermore, Zn/Cu ratio positively correlated with waist circumference (0.13; p = 0.01), systolic blood pressure (0.13; p ˂ 0.01), and DBP (0.14; p ˂ 0.01); and negatively with BMI (−0.19; p ˂ 0.001), PR (−0.17; p ˂ 0.001), and HDL (−0.27; p ˂ 0.001). High Zn/Cu ratio increased the prevalence of low HDL (4.508; p ˂ 0.001) and MetS (5.570; p ˂ 0.01). These findings suggest that high plasma Cu levels are associated with a protective effect on DBP, HDL and MetS and that high plasma Zn/Cu ratio is associated with the risk of having low HDL and MetS.

Environmental pollution and diabetes mellitus

Diabetes mellitus (DM) is a chromic metabolic disease that affects a large segment of the population worldwide. Physical inactivity, poor nutrition, and genetic predisposition are main risk factors for disease development. In the last decade, it was clear to the scientific community that DM development is linked to a novel disease inducer that was later defined as diabetogenic factors of pollution and endocrine disrupting agents. Environmental pollution is exponentially increasing in uncontrolled manner in several countries. Environmental pollutants are of diverse nature and toxicities, including polyaromatic hydrocarbons (PAHs), pesticides, and heavy metals. In the current review, we shed light on the impact of each class of these pollutants and the underlined molecular mechanism of diabetes induction and biological toxicities. Finally, a brief overview about the connection between coronavirus disease 2019 and diabetes pandemics is presented.

Zinc

Since the discovery of manifest Zn deficiency in 1961, the increasing number of studies demonstrated the association between altered Zn status and multiple diseases. In this chapter, we provide a review of the most recent advances on the role of Zn in health and disease (2010-20), with a special focus on the role of Zn in neurodegenerative and neurodevelopmental disorders, diabetes and obesity, male and female reproduction, as well as COVID-19. In parallel with the revealed tight association between ASD risk and severity and Zn status, the particular mechanisms linking Zn2+ and ASD pathogenesis like modulation of synaptic plasticity through ProSAP/Shank scaffold, neurotransmitter metabolism, and gut microbiota, have been elucidated. The increasing body of data indicate the potential involvement of Zn2+ metabolism in neurodegeneration. Systemic Zn levels in Alzheimer's and Parkinson's disease were found to be reduced, whereas its sequestration in brain may result in modulation of amyloid β and α-synuclein processing with subsequent toxic effects. Zn2+ was shown to possess adipotropic effects through the role of zinc transporters, zinc finger proteins, and Zn-α2-glycoprotein in adipose tissue physiology, underlying its particular role in pathogenesis of obesity and diabetes mellitus type 2. Recent findings also contribute to further understanding of the role of Zn2+ in spermatogenesis and sperm functioning, as well as oocyte development and fertilization. Finally, Zn2+ was shown to be the potential adjuvant therapy in management of novel coronavirus infection (COVID-19), underlining the perspectives of zinc in management of old and new threats.

Kidney Adaptations Prevent Loss of Trace Elements in Wistar Rats with Early Metabolic Syndrome

Metabolic syndrome (MetS) represents a cluster of related metabolic abnormalities, including central obesity, hypertension, dyslipidemia, hyperglycemia, and insulin resistance. These metabolic derangements present significant risk factors for chronic kidney disease that carries to loss of essential micronutrients, which accelerates comorbidity apparition. The work aimed was to evaluate the trace element homeostasis regarding morphological adaptations and renal function in MetS early-onset. Fifty male Wistar rats were divided into two groups: (a) control group and (b) hypercaloric diet group that developed MetS early-onset after 3 months. Classical zoometric parameters do not show changes; however, biochemical modifications were observed such as hyperglycemia, protein glycation, insulin resistance, dyslipidemia, hyperinsulinemia, and hypoadiponectinemia. MetS early-onset group observed renal structural modifications, but no functional changes. The structural modifications observed were minimal glomerular injury, glomerular basement membrane thickening, as well as mesangial and tubular cells that showed growth and proliferation. In serum and kidney (cortex and medulla), the concentrations of Zn, Fe, Cr, Mg, Mn, Cu, Co, and Ni were no differences between the experimental groups, but excretory fractions of these were lower in the hypercaloric diet group. In conclusion, MetS early-onset coexist renal structural modification and a hyperreabsorptive activity of essential trace elements that avoid its loss; thus, the excretory fraction of oligo-elements could be used a biomarker of early renal injury caused by metabolic diseases in the clinical practice.

Association of Serum Levels of Zinc, Copper, and Iron with Risk of Metabolic Syndrome

The association between serum concentrations of zinc, copper, or iron and the risk of metabolic syndrome are inconclusive. Therefore, we conduct a case-control study to explore the relationship between serum levels of zinc, copper, or iron and metabolic syndrome as well as each metabolic factor and insulin resistance. We enrolled 1165 adults, aged ≥ 40 (65.8 ± 10) years in a hospital-based population to compare the serum levels of zinc, copper, and iron between subjects with and without metabolic syndrome by using multivariate logistic regression analyses. The least square means were computed by general linear models to compare serum concentrations of zinc, copper, and iron in relation to the number of metabolic factors. The mean serum concentrations of zinc, copper, and iron were 941.91 ± 333.63 μg/L, 1043.45 ± 306.36 μg/L, and 1246.83 ± 538.13 μg/L, respectively. The odds ratios (ORs) of metabolic syndrome for the highest versus the lowest quartile were 5.83 (95% CI: 3.35-10.12; p for trend < 0.001) for zinc, 2.02 (95% CI: 1.25-3.25; p for trend: 0.013) for copper, and 2.11 (95% CI: 1.24-3.62; p for trend: 0.021) for iron after adjusting for age, sex, personal habits, body mass index, and homeostatic model assessment insulin resistance. Additionally, the serum zinc, copper, and iron concentrations increased as the number of metabolic factors rose (p for trend < 0.001). This was the first study to clearly demonstrate that higher serum levels of zinc, copper, and iron were associated with the risk of metabolic syndrome and the number of metabolic factors independent of BMI and insulin resistance.

Zinc Supplementation Decreases Obesity-Related Neuroinflammation and Improves Metabolic Function and Memory in Rats

OBJECTIVE

The purpose of this study was to evaluate the effects of zinc (Zn) supplementation on metabolic and neuroinflammatory parameters in cafeteria diet (CAF)-induced obesity in Wistar rats.

METHODS

Animals were divided into four groups: control diet (CT); CT+Zn; CAF; CAF+Zn. The diet was administered for 20 weeks; Zn treatment (10 mg/kg/d) started at week 16 and it was conducted until the end of the diet protocol. Weight gain, visceral fat, and plasma levels of glucose, triglycerides, insulin, TNF-α, and IL-6, as well as homeostatic model assessment of insulin resistance, were assessed. Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba-1) expression in the cerebral cortex and toll-like receptor 4 (TLR-4) in the cerebral cortex and hippocampus were evaluated. Memory was assessed by the novel object recognition test.

RESULTS

CAF diet increased weight gain, visceral fat, and plasma glucose, triglyceride, and TNF-α levels. Zn reversed the hyperglycemia caused by CAF diet and reduced IL-6 levels. In the cerebral cortex, GFAP was similar between groups; Iba-1 was increased by CAF diet but reduced in the CAF+Zn group. Zn reduced CAF-dependent TLR-4 increase in the hippocampus but not in the cerebral cortex. CAF-fed animals showed impaired recognition memory, whereas Zn reversed it.

CONCLUSIONS

These findings demonstrate that Zn partially reverted obesity-related metabolic dysfunction and reduced neuroinflammation and memory deficit caused by CAF diet.

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.

Trace Elements, PPARs, and Metabolic Syndrome

Metabolic syndrome (MetS) is a constellation of metabolic derangements, including central obesity, insulin resistance, hypertension, glucose intolerance, and dyslipidemia. The pathogenesis of MetS has been intensively studied, and now many factors are recognized to contribute to the development of MetS. Among these, trace elements influence the structure of proteins, enzymes, and complex carbohydrates, and thus an imbalance in trace elements is an independent risk factor for MetS. The molecular link between trace elements and metabolic homeostasis has been established, and peroxisome proliferator-activated receptors (PPARs) have appeared as key regulators bridging these two elements. This is because on one hand, PPARs are actively involved in various metabolic processes, such as abdominal adiposity and insulin sensitivity, and on the other hand, PPARs sensitively respond to changes in trace elements. For example, an iron overload attenuates hepatic mRNA expression of Ppar-α; zinc supplementation is considered to recover the DNA-binding activity of PPAR-α, which is impaired in steatotic mouse liver; selenium administration downregulates mRNA expression of Ppar-γ, thereby improving lipid metabolism and oxidative status in the liver of high-fat diet (HFD)-fed mice. More importantly, PPARs' expression and activity are under the control of the circadian clock and show a robust 24 h rhythmicity, which might be the reasons for the side effects and the clinical limitations of trace elements targeting PPARs. Taken together, understanding the casual relationships among trace elements, PPARs' actions, and the pathogenesis of MetS is of great importance. Further studies are required to explore the chronopharmacological effects of trace elements on the diurnal oscillation of PPARs and the consequent development of MetS.