Copper: effects of deficiency and overload

A novel copper chelator for the suppression of colorectal cancer

Copper ions play a crucial role in the progression of cancers. Tumor tissue is rich in copper ions, and copper chelators could potentially scavenge these copper ions and thus exert an antitumor effect. In this study, we report the synthesis of a novel thieno[3,2-c]pyridine compound we have called "JYFY-001" that can act as the copper chelator thanks to the inclusion of an N-(pyridin-2-yl)acetamide moiety that targets copper ions. JYFY-001 potently inhibited cancer proliferation, inducing cell apoptosis and impairing the extracellular acidification rate and oxygen consumption rate of colorectal cancer (CRC) cells. JYFY-001 also inhibited the growth of a CRC-transplanted tumor in a dose-dependent manner, inducing apoptosis of the tumor cells and promoting the infiltration of lymphocytes in the CRC-transplanted tumor tissues. JYFY-001 also enhanced the antitumor effects of the programmed cell death protein 1 (PD-1) inhibitor. The relatively benign nature of JYFY-001 was demonstrated by the effect on normal cell viability and acute toxicity tests in mice. Our findings suggest that JYFY-001 is a prospective copper chelator to be used as a targeted drug and a synergist of immunotherapy for CRC treatments.

The trace that is valuable: serum copper and copper to zinc ratio for survival prediction in younger patients with newly diagnosed acute myeloid leukaemia

PURPOSE

No data on predicting the survival of AML patients based on the level of trace elements in the serum have been presented to date. The aims of this prospective cohort study were as follows: (i) to evaluate the serum Cu and Zn levels in people from Northeast China, (ii) to assess the association between the serum Cu level (SCL) and Cu to Zn ratio (SCZR) and clinical and nutrition data, and (iii) to investigate the predictive values of the SCL and SCZR in newly diagnosed de novo AML patients.

METHODS

A total of 105 newly diagnosed AML patients and 82 healthy controls were recruited. The serum Cu and Zn levels were determined by inductively coupled plasma spectrometry. The associations of SCL and SCZR with the survival of these AML patients were assessed by Cox proportional hazards models.

RESULTS

Both SCL and SCZR were positively related to the blast percentage of bone marrow and C-reactive protein, negatively related to albumin level and CEBPA double mutation and were significantly associated with worse overall survival and disease-free survival. Meanwhile, patients with higher SCL had worse CTCAE levels, and patients with higher SCZR showed less complete remission during the first course of induction chemotherapy. Moreover, higher SCZR was positively associated with ELN risk stratification, and was negatively associated with haemoglobin level and prognostic nutritional index (PNI).

CONCLUSION

The SCL and SCZR are associated with long-term survival in patients with newly diagnosed AML undergoing intensive induction and may serve as important predictive biomarkers.

Enhanced osteoarthritis therapy by nanoengineered mesenchymal stem cells using biomimetic CuS nanoparticles loaded with plasmid DNA encoding TGF-β1

Mesenchymal stem cells (MSCs) therapy shows the potential benefits to relieve clinical symptoms of osteoarthritis (OA), but it is uncertain if it can repair articular cartilage lesions — the main pathology of OA. Here, we prepared biomimetic cupper sulfide@phosphatidylcholine (CuS@PC) nanoparticles (NPs) loaded with plasmid DNA (pDNA) encoding transforming growth factor-beta 1 (TGF-β1) to engineer MSCs for enhanced OA therapy via cartilage regeneration. We found that the NPs not only promoted cell proliferation and migration, but also presented a higher pDNA transfection efficiency relative to commercial transfection reagent lipofectamine 3000. The resultant CuS/TGF-β1@PC NP-engineered MSCs (termed CTP-MSCs) were better than pure MSCs in terms of chondrogenic gene expression, glycosaminoglycan deposition and type II collagen formation, favoring cartilage repair. Further, CTP-MSCs inhibited extracellular matrix degradation in interleukin-1β-induced chondrocytes. Consequently, intraarticular administration of CTP-MSCs significantly enhanced the repair of damaged cartilage, whereas pure MSCs exhibited very limited effects on cartilage regeneration in destabilization of the medial meniscus (DMM) surgical instability mice. Hence, this work provides a new strategy to overcome the limitation of current stem cell therapy in OA treatment through developing more effective nanoengineered MSCs.

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Biomimetic CuS nanoparticles (NPs) loaded with TGF-β1 pDNA are prepared for nanoengineering of MSCs.

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CuS/TGF-β1@PC NPs are more efficient than commercial transfection agent in terms of pDNA transfection.

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The NP-engineered CTP-MSCs exhibit enhanced migration, chondrogenesis and inhibition of ECM degradation.

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CTP-MSCs effectively treat osteoarthritis (OA) mice models via cartilage regeneration.

Copper(II) complexes with 3,5-dihalogeno-salicylaldehydes: Synthesis, structure and interaction with DNA and albumins

Eight copper(II) complexes of 3,5-dichloro-salicyladehyde or 3,5-dibromo-salicyladehyde (3,5-diX-saloH, X = Br or Cl) were synthesized in the absence or presence of a N,N'-donor co-ligand such as 2,2'-bipyridylamine, 1,10-phenanthroline, or 2,2'-bipyridine. The resultant compounds were formulated as [Cu(3,5-diX-salo)₂(MeOH)₂] (1-2) and [Cu(3,5-diX-salo)(N,N'-donor)Cl] (3-8) and were characterized by diverse techniques. The crystal structures of three complexes were determined by single-crystal X-ray crystallography. Diverse techniques were employed in order to investigate the interaction of the complexes with calf-thymus DNA which showed intercalation as the most possible mode of their interaction. The affinity of the complexes for bovine serum albumin and human serum albumin was evaluated by fluorescence emission spectroscopy in order to calculate the binding constants which suggested a tight and reversible binding. SYNOPSIS: A series of copper(II) complexes with 3,5-dihalogen-substituted salicylaldehydes as ligands were isolated and characterized. In vitro biological studies showed the intercalation of the compounds with calf-thymus DNA and their tight and reversible binding with serum albumins.

A cuproptosis-related LncRNA signature: Integrated analysis associated with biochemical recurrence and immune landscape in prostate cancer

Background: As a new form of regulated cell death, cuproptosis differs profoundly from apoptosis, ferroptosis, pyroptosis, and necroptosis. The correlation between cuproptosis and long non-coding RNAs (lncRNAs) has been increasingly studied recently. In this study, a novel cuproptosis-related lncRNA prognostic signature was developed to investigate biochemical recurrence (BCR) and tumor immune landscape in prostate cancer (PCa). Methods and Materials: The transcriptome data and clinicopathologic information of PCa patients were downloaded from The Cancer Genome Atlas (TCGA). Pearson's correlation analysis was applied to identify lncRNAs associated with cuproptosis. Based on Cox regression analysis and the least absolute shrinkage and selection operator (LASSO) regression analysis, we developed a cuproptosis-related lncRNA prognostic model (risk score) to predict the BCR of PCa patients. Additionally, we also constructed a nomogram with the risk score and clinicopathologic features. The biological function, tumor mutation burden (TMB), immune cell infiltration, expression levels of immune checkpoint genes, and anti-cancer drug sensitivity were investigated. Results: We constructed and validated the cuproptosis-related lncRNA signature prognostic model (risk score) by six crlncRNAs. All patients were divided into the low- and high-risk groups based on the median risk score. The Kaplan-Meier (KM) survival analysis revealed that the high-risk group had shorter BCR-free survival (BCRFS). The risk score has been proven to be an independent prognostic factor of BCR in PCa patients. In addition, a nomogram of risk scores and clinicopathologic features was established and demonstrated an excellent predictive capability of BCR. The ROC curves further validated that this nomogram had higher accuracy of predicting the BCR compared to other clinicopathologic features. We also found that the high-risk group had higher TMB levels and more infiltrated immune cells. Furthermore, patients with high TMB in the high-risk group were inclined to have the shortest BCRFS. Finally, patients in the high-risk group were more susceptible to docetaxel, gefitinib, methotrexate, paclitaxel, and vinblastine. Conclusion: The novel crlncRNA signature prognostic model shows a greatly prognostic prediction value of BCR for PCa patients, extends our thought on the association of cuproptosis and PCa, and provides novel insights into individual-based treatment strategies for PCa.

Single and Combined Associations of Plasma and Urine Essential Trace Elements (Zn, Cu, Se, and Mn) with Cardiovascular Risk Factors in a Mediterranean Population

Trace elements are micronutrients that are required in very small quantities through diet but are crucial for the prevention of acute and chronic diseases. Despite the fact that initial studies demonstrated inverse associations between some of the most important essential trace elements (Zn, Cu, Se, and Mn) and cardiovascular disease, several recent studies have reported a direct association with cardiovascular risk factors due to the fact that these elements can act as both antioxidants and pro-oxidants, depending on several factors. This study aims to investigate the association between plasma and urine concentrations of trace elements and cardiovascular risk factors in a general population from the Mediterranean region, including 484 men and women aged 18−80 years and considering trace elements individually and as joint exposure. Zn, Cu, Se, and Mn were determined in plasma and urine using an inductively coupled plasma mass spectrometer (ICP-MS). Single and combined analysis of trace elements with plasma lipid, blood pressure, diabetes, and anthropometric variables was undertaken. Principal component analysis, quantile-based g-computation, and calculation of trace element risk scores (TERS) were used for the combined analyses. Models were adjusted for covariates. In single trace element models, we found statistically significant associations between plasma Se and increased total cholesterol and systolic blood pressure; plasma Cu and increased triglycerides and body mass index; and urine Zn and increased glucose. Moreover, in the joint exposure analysis using quantile g-computation and TERS, the combined plasma levels of Zn, Cu, Se (directly), and Mn (inversely) were strongly associated with hypercholesterolemia (OR: 2.03; 95%CI: 1.37−2.99; p < 0.001 per quartile increase in the g-computation approach). The analysis of urine mixtures revealed a significant relationship with both fasting glucose and diabetes (OR: 1.91; 95%CI: 1.01−3.04; p = 0.046). In conclusion, in this Mediterranean population, the combined effect of higher plasma trace element levels (primarily Se, Cu, and Zn) was directly associated with elevated plasma lipids, whereas the mixture effect in urine was primarily associated with plasma glucose. Both parameters are relevant cardiovascular risk factors, and increased trace element exposures should be considered with caution.

Copper Effect on Microalgae: Toxicity and Bioremediation Strategies

Microalgae are increasingly recognised as suitable microorganisms for heavy metal (HM) removal, since they are able to adsorb them onto their cell wall and, in some cases, compartmentalise them inside organelles. However, at relatively high HM concentrations, they could also show signs of stress, such as organelle impairments and increased activities of antioxidant enzymes. The main aim of this review is to report on the mechanisms adopted by microalgae to counteract detrimental effects of high copper (Cu) concentrations, and on the microalgal potential for Cu bioremediation of aquatic environments. Studying the delicate balance between beneficial and detrimental effects of Cu on microalgae is of particular relevance as this metal is widely present in aquatic environments facing industrial discharges. This metal often induces chloroplast functioning impairment, generation of reactive oxygen species (ROS) and growth rate reduction in a dose-dependent manner. However, microalgae also possess proteins and small molecules with protective role against Cu and, in general, metal stress, which increase their resistance towards these pollutants. Our critical literature analysis reveals that microalgae can be suitable indicators of Cu pollution in aquatic environments, and could also be considered as components of eco-sustainable devices for HM bioremediation in association with other organisms.

Integrating Transcriptomics and Free Fatty Acid Profiling Analysis Reveal Cu Induces Shortened Lifespan and Increased Fat Accumulation and Oxidative Damage in C. elegans

Nowadays, human beings are exposed to Cu in varieties of environmental mediums, resulting in health risks needing urgent attention. Our research found that Cu shortened lifespan and induced aging-related phenotypes of Caenorhabditis elegans (C. elegans). Transcriptomics data showed differential expression genes induced by Cu were mainly involved in regulation of metabolism and longevity, especially in fatty acid metabolism. Quantitative detection of free fatty acid by GC/MS further found that Cu upregulated free fatty acids of C. elegans. A mechanism study confirmed that Cu promoted the fat accumulation in nematodes, which was owing to disorder of fatty acid desaturase and CoA synthetase, endoplasmic reticulum unfolded protein response (UPR^ER), mitochondrial membrane potential, and unfolded protein response (UPR^mt). In addition, Cu activated oxidative stress and prevented DAF-16 translocating into nuclear with a concomitant reduction in the expression of environmental stress-related genes. Taken together, the research suggested that Cu promoted aging and induced fat deposition and oxidative damage.

Toxic metals that interact with thiol groups and alteration in insect behavior

Toxic metals, such as mercury (Hg), lead (Pb), cadmium (Cd), and copper (Cu), are widespread in the biosphere, and human activities have contributed to their continuous release into the ecosystems. Metal-induced toxicity has been extensively studied in mammals; however, the effects of these metals on insects' behavior have been explored to far lesser degree. As the main mechanism of toxicity, the cationic metals, explored in this review, have high affinity for thiol-containing molecules, disrupting the function of several proteins and low-molecular-weight thiol-containing molecules. Existing literature has corroborated that Hg, Pb, Cd, and Cu can disrupt locomotor and mating behaviors, but their effects on insects' memory and learning have yet to be fully characterized. Though field studies on metal-induced toxicity in insects are limited, results from Drosophila melanogaster as an experimental model suggest that insects living in contaminated environments can have behavioral foraging and reproductive deficits, which may cause population decline. In this review, we address the interaction between metals and endogenous thiol groups, with emphasis on alterations in insect behavior.

Effect of Sublethal Copper Overload on Cholesterol De Novo Synthesis in Undifferentiated Neuronal Cells

Although copper (Cu) is an essential trace metal for cells, it can induce harmful effects as it participates in the Fenton reaction. Involuntary exposure to Cu overload is much more common than expected and has been linked with neurodegeneration, particularly with Alzheimer's disease (AD) evidenced by a positive correlation between free Cu in plasma and the severity of the disease. It has been suggested that Cu imbalance alters cholesterol (Chol) homeostasis and that high membrane Chol promotes the amyloidogenic processing of the amyloid precursor protein (APP) secreting the β-amyloid (Aβ) peptide. Despite the wide knowledge on the effects of Cu in mature brain metabolism, the consequence of its overload on immature neurons remains unknown. Therefore, we used an undifferentiated human neuroblastoma cell line (SH-SY5Y) to analyze the effect of sublethal concentrations of Cu on 1- de novo Chol synthesis and membrane distribution; 2-APP levels in cells and its distribution in membrane rafts; 3-the levels of Aβ in the culture medium. Our results demonstrated that Cu increases reactive oxygen species (ROS) and favors Chol de novo synthesis in both ROS-dependent and independent manners. Also, at least part of these effects was due to the activation of 3-hydroxy-3-methyl glutaryl CoA reductase (HMGCR). In addition, Cu increases the Chol/PL ratio in the cellular membranes, specifically Chol content in membrane rafts. We found no changes in total APP cell levels; however, its presence in membrane rafts increases with the consequent increase of Aβ in the culture medium. We conclude that Cu overload favors Chol de novo synthesis in both ROS-dependent and independent manners, being at least in part, responsible for the high Chol levels found in the cell membrane and membrane rafts. These may promote the redistribution of APP into the rafts, favoring the amyloidogenic processing of this protein and increasing the levels of Aβ.

Ferroptosis as a mechanism of non-ferrous metal toxicity

Ferroptosis is a recently discovered form of regulated cell death, implicated in multiple pathologies. Given that the toxicity elicited by some metals is linked to alterations in iron metabolism and induction of oxidative stress and lipid peroxidation, ferroptosis might be involved in such toxicity. Although direct evidence is insufficient, certain pioneering studies have demonstrated a crosstalk between metal toxicity and ferroptosis. Specifically, the mechanisms underlying metal-induced ferroptosis include induction of ferritinophagy, increased DMT-1 and TfR cellular iron uptake, mitochondrial dysfunction and mitochondrial reactive oxygen species (mitoROS) generation, inhibition of Xc-system and glutathione peroxidase 4 (GPX4) activity, altogether resulting in oxidative stress and lipid peroxidation. In addition, there is direct evidence of the role of ferroptosis in the toxicity of arsenic, cadmium, zinc, manganese, copper, and aluminum exposure. In contrast, findings on the impact of cobalt and nickel on ferroptosis are scant and nearly lacking altogether for mercury and especially lead. Other gaps in the field include limited studies on the role of metal speciation in ferroptosis and the critical cellular targets. Although further detailed studies are required, it seems reasonable to propose even at this early stage that ferroptosis may play a significant role in metal toxicity, and its modulation may be considered as a potential therapeutic tool for the amelioration of metal toxicity.

Associations of Copper Intake with Bone Mineral Density and Osteoporosis in Adults: Data from the National Health and Nutrition Examination Survey

Some studies have suggested an association between serum copper and bone density. Few studies have explored the association between copper intake and osteoporosis and bone mineral density (BMD). Our research aims to assess the associations of copper intake with the risk of osteoporosis in United States adults using the National Health and Nutritional Examination Surveys (NHANES). A total of 8224 individuals were included in our study. Osteoporosis was defined that BMD values surpass 2.5 standard deviations (SD) below the mean of the young adult reference group. Copper intake from diets and supplements was estimated by using two 24-h recall surveys. After adjustment for all the covariates of interest, the odds ratios (ORs) (95% confidence interval (CI)) between the risk of osteoporosis and total copper intake across quartiles 3 and 4 compared with quartile 1 were 0.48 (0.31-0.74) (P < 0.01) and 0.41 (0.26-0.65) (P < 0.01), respectively. The mean total femur BMD and total spine BMD of the highest dietary copper intake quartile (Cu 1.51 mg/d) was 0.03 g/cm² and 0.02 g/cm² greater than the lowest quartile. Our results indicate that dietary and total copper intake was positively associated with increasing BMD in US adults and negatively associated with the risk of osteoporosis in US adults.

Multiple nutritional and gut microbial factors associated with allergic rhinitis: the Hitachi Health Study

Several studies suggest the involvement of dietary habits and gut microbiome in allergic diseases. However, little is known about the nutritional and gut microbial factors associated with the risk of allergic rhinitis (AR). We recruited 186 participants with symptoms of AR and 106 control subjects without symptoms of AR at the Hitachi Health Care Center, Japan. The habitual consumption of 42 selected nutrients were examined using the brief-type self-administered diet history questionnaire. Faecal samples were collected and subjected to amplicon sequencing of the 16S ribosomal RNA gene hypervariable regions. Association analysis revealed that four nutrients (retinol, vitamin A, cryptoxanthin, and copper) were negatively associated with AR. Among 40 genera examined, relative abundance of Prevotella and Escherichia were associated with AR. Furthermore, significant statistical interactions were observed between retinol and Prevotella. The age- and sex-adjusted odds of AR were 25-fold lower in subjects with high retinol intake and high Prevotella abundance compared to subjects with low retinol intake and low Prevotella abundance. Our data provide insights into complex interplay between dietary nutrients, gut microbiome, and the development of AR.

Do glutathione and copper interact to modify Alzheimer's disease pathogenesis?

Alzheimer's disease (AD) is a progressive neurodegenerative disorder first described in 1906 that is currently estimated to impact ∼40 million people worldwide. Extensive research activities have led to a wealth of information on the pathogenesis, hallmarks, and risk factors of AD; however, therapeutic options remain extremely limited. The large number of pathogenic factors that have been reported to potentially contribute to AD include copper dyshomeostasis as well as increased oxidative stress, which is related to alterations to molecular antioxidants like glutathione (GSH). While the individual roles of GSH and copper in AD have been studied by many research groups, their interactions have received relatively little attention, although they appear to interact and affect each other's regulation. Existing knowledge on how GSH-copper interactions may affect AD is sparse and lacks focus. This review first highlights the most relevant individual roles that GSH and copper play in physiology and AD, and then collects and assesses research concerning their interactions, in an effort to provide a more accessible and understandable picture of the role of GSH, copper, and their interactions in AD.

Copper Induces Spleen Damage Through Modulation of Oxidative Stress, Apoptosis, DNA Damage, and Inflammation

Copper (Cu) is an essential micronutrient for both humans and animals; however, excessive intake of Cu can be immunotoxic. There are limited studies on spleen toxicity induced by Cu. This study was conducted to investigate the effects of Cu on spleen oxidative stress, apoptosis, and inflammatory responses in mice orally administered with 0 mg/kg, 10 mg/kg, 20 mg/kg, and 40 mg/kg of CuSO₄ for 42 days. As discovered in this work, copper sulfate (CuSO₄) reduced the activities of antioxidant enzymes (SOD, CAT, and GSH-Px), decreased GSH contents, and increased MDA contents. Meanwhile, CuSO₄ induced apoptosis by increasing TUNEL-positive cells in the spleen. Also, CuSO₄ increased the expression of γ-H2AX, which is the marker of DNA damage. Concurrently, CuSO₄ caused inflammation by increasing the mRNA levels of interleukin-1β (IL-1β), IL-2, IL-4, IL-6, IL-12, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). In conclusion, the abovementioned findings demonstrate that over 10 mg/kg CuSO₄ can cause oxidative stress, apoptosis, DNA damage, and inflammatory responses, which contribute to spleen dysfunction in mice.

A Simple Colorimetric Assay for Sensitive Cu2+ Detection Based on the Glutathione-Mediated Etching of MnO2 Nanosheets

In this paper, we developed a quick, economical and sensitive colorimetric strategy for copper ions (Cu²⁺) quantification via the redox response of MnO₂ nanosheets with glutathione (GSH). This reaction consumed MnO₂ nanosheets, which acted as a catalyst for the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to a blue product (oxTMB). In the presence of Cu²⁺, the GSH was catalyzed to GSSG (oxidized glutathione), and the solution changed from colorless to deep blue. Under the optimum conditions, the absorption signal of the oxidized product (oxTMB) became proportional to Cu²⁺ concentration in the range from 10 to 300 nM with a detection limit of 6.9 nM. This detection system showed high specificity for Cu²⁺. Moreover, the system has been efficaciously implemented for Cu²⁺ detection in actual tap water samples. The layered-nanostructures of MnO₂ nanosheets make it possess high chemical and thermal stability. TMB can be quickly oxidized within 10 min by the catalyzing of MnO₂ nanosheets with high oxidase-like activity. There is no need of expensive reagents, additional H₂O₂ and complicated modification processes during the colorimetric assay. Therefore, the strategy primarily based on MnO₂ nanosheets is promising for real-time, rapid and highly sensitive detection of Cu²⁺ under practical conditions.

Induction of autophagy via the ROS-dependent AMPK-mTOR pathway protects copper-induced spermatogenesis disorder

Copper (Cu) is a necessary micronutrient at lower concentration, while excessive Cu exposure or Cu homeostasis disorders can lead to toxicity. The mechanism of male reproductive toxicity induced by Cu is still unknown. This study aims to investigate whether autophagy plays an important role in copper-induced spermatogenesis disorder in vivo and vitro. The present study showed that copper sulfate (CuSO₄) might significantly promote autophagy level in the testis and mouse-derived spermatogonia cell line GC-1 spg cells. Concurrently, CuSO₄ could induce autophagy via AMPK-mTOR pathway that downregulated p-mTOR/mTOR and subsequently upregulated p-AMPKα/AMPKα as well as p-ULK1/ULK1. In the meanwhile, CuSO₄ treatment could also increase expression levels of the autophagy-related proteins. Then, the role of oxidative stress in CuSO₄-induced autophagy was investigated. The findings demonstrated that oxidative stress inhibitor (NAC) attenuated CuSO₄-induced autophagy in vivo and vitro, reversing the activation for AMPK-mTOR pathway. Additionally, the study also investigated how autophagy worked under the spermatogenesis disorder induced by CuSO₄. Inhibition of autophagy could decrease cell viability, and enhance the ROS accumulation and apoptosis in the GC-1 cells, meanwhile, the spermatogenesis disorder, oxidative stress and histopathological changes were increased in the testis. Furthermore, co-treatment with the apoptosis inhibitor (Z-VAD-FMK) could decrease the spermatogenesis disorder but not influence autophagy. Besides, the crosslink between autophagy and ferroptosis were also measured, the data showed that inhibition of autophagy could suppress CuSO₄-induced ferroptosis in in vivo and vitro. Altogether, abovementioned results indicated that CuSO₄ induced autophagy via oxidative stress-dependent AMPK-mTOR pathway in the GC-1 cells and testis, and autophagy activation possibly led to the generation of protection mechanism through oxidative damage and apoptosis inhibition, however, autophagy also aggravate CuSO₄ toxicology through promoting ferroptosis. Overall, autophagy plays a positive role for attenuating CuSO₄-induced testicular damage and spermatogenesis disorder. Our study provides a possible targeted therapy for Cu overload-induced reproduction toxicology.

The association between essential trace element (copper, zinc, selenium, and cobalt) status and the risk of early embryonic arrest among women undergoing assisted reproductive techniques

BACKGROUND

Early embryonic arrest (EEA) leads to repeated cessation of fresh cycles among infertile women undergoing in vitro fertilization (IVF). Whether the levels of some essential trace elements [copper (Cu), zinc (Zn), selenium (Se) and cobalt (Co)] in the bodies of women are related to the risk of EEA warrants study.

OBJECTIVE

Our study aimed to investigate the associations of peripheral blood levels of Cu, Zn, Se, and Co and their mixtures with the risk of EEA.

METHODS

A total of 74 EEA cases (123 IVF cycles) and 157 controls (180 IVF cycles) from the reproductive center of the First Affiliated Hospital of Anhui Medical University in Hefei, China, between June 2017 and March 2020 were included in our study. Demographic and clinical data were collected from electronic medical records. Cu, Zn, Se, and Co levels were measured in blood samples collected on the day of oocyte retrieval when infertile women entered clinical treatment for the first time using an inductively coupled plasma mass spectrometer (ICP-MS). Generalized estimating equation (GEE) models were used to evaluate the associations of four essential trace element concentrations individually with the risk of EEA, and Bayesian kernel machine regression (BKMR) was used to explore the associations between four essential trace element mixtures and the risk of EEA.

RESULTS

Se concentrations of infertile women were significantly lower in the case group compared with the control group. Co levels were significantly higher in the case group compared with the control group. The differences in Cu and Zn concentrations between the two groups were not significant. Based on single-metal models, Co was positively associated with the risk of EEA before and after adjustment for all confounders (odd ratio (OR) = 1.72, 95% confidence interval (CI): 1.18-2.52; OR = 2.27, 95% CI: 1.37-3.77, respectively), and Se was negatively associated with the risk of EEA before adjustment for all confounders (OR = 0.18, 95% CI: 0.07-0.51). BKMR analyses showed that Se was significantly and negatively associated with the risk of EEA when all the other three metals (Cu, Zn, and Co) were fixed at the 25th, 50th, or 75th percentiles, whereas Zn displayed a significant and positive association with the risk of EEA when all the other three metals (Cu, Se and Co) were fixed at the 25th, 50th, or 75th percentiles. Co did not show any effect on the risk of EEA when all the other metals (Cu, Zn, and Se) were fixed at the 25th, 50th, or 75th percentiles. In addition, an increasing trend of the joint effect of four essential trace elements on the risk of EEA was found, although it was not statistically significant.

CONCLUSION

The levels of essential trace elements (Cu, Zn, Se, and Co) might correlate with the risk of EEA to some extent. The present study might provide a real-world perspective on the relationship between essential trace elements and the risk of EEA when considering them as a single element or as mixtures.

Study on metal binding capacity of the freshwater crab Sinopotamon henanense's recombinant copper specific binding metallothionein expressed in Escherichia coli

The copper specific binding metallothionein (CuMT) is a type of cysteine-rich, metal-binding, small protein which plays an important role in Cu²⁺ metabolism in vertebrates. In this study, we investigated the metal tolerance and removing ability of recombinant strains harboring CuMT obtained in vivo from the freshwater crab Sinopotamon henanense (ShCuMT) in order to study its physiological functions and metal binding capacity. We performed a 3D modeling of ShCuMT and created its structural and functional models using the I-TASSER program. The shCumt gene was inserted into a pGEX-4t-1 vector and recombinant soluble ShCuMT was expressed in Escherichia coli. In addition, in order to characterize the tolerance and removing ability of heavy metals in E. coli with ShCuMT expression, the recombinant strains harboring ShCuMT were exposed to various concentrations of Cd²⁺, Cu²⁺ and Zn²⁺, respectively. The results showed that ShCuMT contains transition metal binding sites. In addition, E. coli cells expressing ShCuMT exhibited enhanced metal tolerance and higher removing ability of metal ions than control cells. However, compared with Cd²⁺ and Zn²⁺, E. coli cells expressing ShCuMT have stronger tolerance and higher removing ability of Cu²⁺. In general, ShCuMT contains multiple transition metal binding sites, and it could enhance tolerance and removing ability of metal ions. Therefore, ShCuMT can provide potential candidates for heavy metal bioremediation. This research on the metal binding properties of ShCuMT provides a scientific basis for bioremediation of heavy metal pollution by the recombinant strains.

Copper in the tumor microenvironment and tumor metastasis

Copper (Cu), an essential micronutrient, plays an essential role in several physiological processes, including cell proliferation and angiogenesis; however, its dysregulation induces oxidative stress and inflammatory responses. Significant Cu accumulation is observed in several tumor tissues. The bioavailability of intracellular Cu is tightly controlled by Cu transporters, including Cu transporter 1 (CTR1) and Cu-transporting P-type ATPase α and β (ATP7A and ATP7B), and Cu chaperones, including Cu chaperone for superoxide dismutase 1 (CCS) and antioxidant-1 (Atox-1). In several tumor tissues, these abnormalities that induce intra­cellular Cu accumulation are involved in tumor progression. In addition, functional disturbance in Cu-containing secretory enzymes, such as superoxide dismutase 3 (SOD3), and lysyl oxidase enzymes (LOX and LOXL1–4) with abnormal Cu dynamics plays a key role in tumor metastasis. For example, the loss of SOD3 in tumor tissues induces oxidative stress, which promotes neovascularization and epithelial-to-mesenchymal transition (EMT). LOX promotes collagen crosslinking, which functions in the metastatic niche formation. Accordingly, restricted Cu regulation may be a novel strategy for the inhibition of tumor metastasis. However, it is unclear how these Cu disturbances occur in tumor tissues and the exact molecular mechanisms underlying Cu secretory enzymes. In this review article, I discuss the role of Cu transporters, Cu chaperones, and Cu-containing secretory enzymes in tumor progression to better understand the role of Cu homeostasis in tumor tissues.

A centrifuge-less cloud point extraction-spectrophotometric determination of copper(II) using 6-hexyl-4-(2-thiazolylazo)resorcinol

A simple, cheap, and environmentally friendly centrifuge-less cloud point extraction procedure was developed for the preconcentration of traces of Cu(II) before its spectrophotometric determination. It is based on a complexation reaction with the hydrophobic azo reagent 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR), in which a complex with a stoichiometric ratio of 1:1 and an absorption maximum at 535 nm is formed. The experimental conditions for Cu(II) determination were found: HTAR concentration (8 × 10^-6 mol mL^-1), mass fraction of the surfactant Triton X-114 (2.2%), pH (5.9, ammonium acetate buffer), and incubation time (10 min at 60 °C). The linear range, limit of detection, molar absorption coefficient and preconcentration factor were calculated to be 4.5-254 ng mL^-1, 1.34 ng mL^-1, 2.54 × 10⁵ L mol^-1 cm^-1, and 10, respectively. The effect of foreign ions was studied, and the proposed procedure was applied to the analysis of water samples and a saline solution for intravenous infusion.

Evaluation of in vitro activity of copper gluconate against SARS-CoV-2 using confocal microscopy-based high content screening

CONTEXT

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that emerged late in 2019 is the etiologic agent of coronavirus disease 2019 (Covid-19). There is an urgent need to develop curative and preventive therapeutics to limit the current pandemic and to prevent the re-emergence of Covid-19. This study aimed to assess the in vitro activity of copper gluconate against SARS-CoV-2.

METHODS

Vero E6 cells were cultured with or without copper gluconate 18-24 hours before infection. Cells were infected with a recombinant GFP expressing SARS-CoV-2. Cells were infected with a recombinant GFP expressing SARS-CoV-2. Infected cells were incubated in fresh medium containing varying concentration of copper gluconate (supplemented with bovine serum albumin or not) for an additional 48 -h period. The infection level was measured by the confocal microscopy-based high content screening method. The cell viability in presence of copper gluconate was assessed by XTT and propidium iodide assays.

RESULTS

The viability of Vero E6 cells exposed to copper gluconate up to 200 μM was found to be similar to that of unexposed cells, but it dropped below 70 % with 400 μM of this agent after 72 h of continuous exposure. The infection rate was 23.8 %, 18.9 %, 20.6 %, 6.9 %, 5.3 % and 5.2 % in cells treated prior infection with 0, 2, 10, 25, 50 and 100 μM of copper gluconate respectively. As compared to untreated cells, the number of infected cells was reduced by 71 %, 77 %, and 78 % with 25, 50, and 100 μM of copper gluconate respectively (p < 0.05). In cells treated only post-infection, the rate of infection dropped by 73 % with 100 μM of copper gluconate (p < 0.05). However, the antiviral activity of copper gluconate was abolished by the addition of bovine serum albumin.

CONCLUSION

Copper gluconate was found to mitigate SARS-CoV-2 infection in Vero E6 cells but this effect was abolished by albumin, which suggests that copper will not retain its activity in serum. Furthers studies are needed to investigate whether copper gluconate could be of benefit in mucosal administration such as mouthwash, nasal spray or aerosols.

Human serum elements' levels and leukemia: A first pilot study from an adult Greek cohort

BACKGROUND

The present study focuses on the evaluation of potential relationships between trace elements and acute and chronic types of leukemia, via the determination of their levels in human blood serum.

METHODS

A total of 199 serum samples from a Greek cohort were examined, including both leukemia cases and controls. Elements' analysis was carried out using inductively coupled plasma mass spectrometry (ICP-MS) and demographic features such as age, gender, smoking habits and area of residence were recorded and statistically treated applying Shapiro-Wilk, Kolmogorov-Smirnov, Mann Whitney and Kruskal Wallis tests (p < 0.05). Spearman correlation and principal component analysis (PCA) were also performed to investigate possible associations.

RESULTS

The results demonstrated significantly higher (p < 0.05) trace elements concentrations in cases' serum compared to that of controls excluding Ba, with Cu (median concentration 1295 μg L^-1) being the most abundant in cases. Additionally, concentration of toxic Pb and Cd were found at seven and four fold higher concentrations in cases, respectively. Among the trace elements examined, only Rb (164 μg L^-1) was detected in higher concentrations in controls. Ba, Cd and Co presented the lowest concentrations (lower than 1 μg L^-1). PCA was performed for overall and classified data, indicating a stronger relation among the toxic As, Cd, Ni and Pb in cases than controls, particularly referring to smokers and industrial sites' residents. Hematological parameters and factors such as age and gender did not present any significant outcome or correlation.

CONCLUSIONS

The findings from this pilot study suggest a potential relationship between metals and leukemia, especially concerning the toxic ones. Results from the employed source apportionment tools imply that smoking and atmospheric degradation may be positively related with higher metal serum levels in leukemia patients.

Elesclomol induces copper-dependent ferroptosis in colorectal cancer cells via degradation of ATP7A

Cancer cells reprogram their copper metabolism to adapt to adverse microenvironments, such as oxidative stress. The copper chelator elesclomol has been reported to have considerable anticancer efficacy, but the underlying mechanisms remain largely unknown. In this study, we found that elesclomol-mediated copper overload inhibits colorectal cancer (CRC) both in vitro and in vivo. Elesclomol alone promotes the degradation of the copper transporter copper-transporting ATPase 1 (ATP7A), which retards the proliferation of CRC cells. This property distinguishes it from several other copper chelators. Combinational treatment of elesclomol and copper leads to copper retention within mitochondria due to ATP7A loss, leading to reactive oxygen species accumulation, which in turn promotes the degradation of SLC7A11, thus further enhancing oxidative stress and consequent ferroptosis in CRC cells. This effect accounts for the robust antitumour activity of elesclomol against CRC, which can be reversed by the administration of antioxidants and ferroptosis inhibitors, as well as the overexpression of ATP7A. In summary, our findings indicate that elesclomol-induced copper chelation inhibits CRC by targeting ATP7A and regulating ferroptosis.

Correlation between urinary contents of some metals and fasting plasma glucose levels: A cross-sectional study in China

Many metals are involved in the pathogenesis of diabetes, but most of existing studies focused on single metals. The study of mixtures represents real-life exposure scenarios and deserves attention. This study aimed to explore the potential relationship of urinary copper (Cu), zinc (Zn), arsenic (As), selenium (Se), and strontium (Sr) contents with fasting plasma glucose (FPG) levels in 2766 participants. The levels of metals in urine were determined by inductively coupled plasma-mass spectrometry. We used linear regression models and the Bayesian kernel machine regression (BKMR) to evaluate the association between metals and FPG levels. In the multiple metals linear regression, Zn (β = 0.434), Se (β = 0.172), and Sr (β = -0.143) showed significant association with FPG levels (all P < 0.05). The BKMR model analysis showed that the results of single metal association were consistent with the multiple metals linear regression. The mixture of five metals had a positive over-all effect on FPG levels, and Zn (PIP = 1.000) contributed the most to the FPG levels. Cu and As were negatively correlated with FPG levels in women. The potential interaction effect between Cu and Sr was observed in participants aged ≥ 60 years old (Pinteraction = 0.035). In summary, our results suggested that multiple metals in urine are associated with FPG levels. Further studies are needed to confirm these findings and clarify the underlying mechanisms.

Copper induces mitochondria-mediated apoptosis via AMPK-mTOR pathway in hypothalamus of Pigs

Copper (Cu), one of the heavy metals, is far beyond the carrying capacity of the environment with Cu mining, industrial wastewater discharging and the use of Cu-containing pesticides. Intaking excess Cu can cause toxic effects on liver, kidney, heart, but few studies report Cu toxicity on brain tissue. It is noteworthy that most toxicity tests are based on rodent models, but large mammals chosen as animal models has no reported. To explore the relationship of the Cu toxicity and mitochondria-mediated apoptosis on hypothalamus in pigs, the content of Cu, histomorphology, mitochondrial related indicators, apoptosis, and AMPK-mTOR signaling pathway were detected. Results showed that Cu could accumulate in hypothalamus and lead to mitochondrial dysfunction, evidenced by the decrease of ATP production, activities of respiratory chain complex I-IV, and mitochondrial respiratory function in Cu-treated groups. Additionally, the genes and proteins expression of Bax, Caspase-3, Cytc in treatment group were higher than control group. Furthermore, the protein level of p-AMPK was enhanced significantly and p-mTOR was declined, which manifested that AMPK-mTOR signaling pathway was activated in Cu-treated groups. In conclusion, this study illuminated that the accumulation of Cu could cause mitochondrial dysfunction, induce mitochondria-mediated apoptosis and activate AMPK-mTOR pathway in hypothalamus.

Saccharomyces cerevisiae DNA repair pathways involved in repair of lesions induced by mixed ternary mononuclear Cu(II) complexes based on valproic acid with 1,10-phenanthroline or 2,2'- bipyridine ligands

The sodium valproate has been largely used as an anti-epilepsy drug and, recently, as a putative drug in cancer therapy. However, the treatment with sodium valproate has some adverse effects. In this sense, more effective and secure complexes than sodium valproate should be explored in searching for new active drugs. This study aims to evaluate the cytotoxicity of sodium valproate, mixed ternary mononuclear Cu(II) complexes based on valproic acid (VA) with 1,10-phenanthroline (Phen) or 2,2'- bipyridine (Bipy) ligands - [Cu₂(Valp)₄], [Cu(Valp)₂Phen] and [Cu(Valp)₂Bipy] - in yeast Saccharomyces cerevisiae, proficient or deficient in different repair pathways, such as base excision repair (BER), nucleotide excision repair (NER), translesion synthesis (TLS), DNA postreplication repair (PRR), homologous recombination (HR) and non-homologous end-joining (NHEJ). The results indicated that the Cu(II) complexes have higher cytotoxicity than sodium valproate in the following order: [Cu(Valp)₂Phen] > [Cu(Valp)₂Bipy] > [Cu₂(Valp)₄] > sodium valproate. The treatment with Cu(II) complexes and sodium valproate induced mutations in S. cerevisiae. The data indicated that yeast strains deficient in BER (Ogg1p), NER (complex Rad1p-Rad10p) or TLS (Rev1p, Rev3p and Rad30p) proteins are associated with increased sensitivity to sodium valproate. The BER mutants (ogg1Δ, apn1Δ, rad27Δ, ntg1Δ and ntg2Δ) showed increased sensitivity to Cu(II) complexes. DNA damage induced by the complexes requires proteins from NER (Rad1p and Rad10p), TLS (Rev1p, Rev3p and Rad30p), PRR (Rad6 and Rad18p) and HR (Rad52p and Rad50p) for efficient repair. Therefore, Cu(II) complexes display enhanced cytotoxicity when compared to the sodium valproate and induce distinct DNA lesions, indicating a potential application as cytotoxic agents.

Cu-induced spermatogenesis disease is related to oxidative stress-mediated germ cell apoptosis and DNA damage

Copper is considered as an indispensable trace element for living organisms. However, over-exposure to Cu can lead to adverse health effects on human. In this study, CuSO₄ decreased sperm concentration and motility, increased sperm malformation rate. Concurrently, testicular damage including testicular histopathological aberrations and reduction of testis relative weight were observed. Then, the mechanism underlying Cu-induced testicular toxicity was explored. According to the results, CuSO₄ elevated ROS production while reducing antioxidant function. Additionally, CuSO₄ induced apoptosis which was featured by MMP depolarization and up-regulated levels of cleaved-caspase-3, cleaved-caspase-8, cleaved-caspase-9, caspase-12, cleaved-PARP and Bax, whereas down-regulated Bcl-2 expression. Meanwhile, CuSO₄ caused testis DNA damage (up-regulation of γ-H2AX protein expression) and suppressed DNA repair pathways including BER, NER, HR, MMR, together with the NHEJ repair pathways, yet did not affect MGMT. To investigate the role of oxidative stress in CuSO₄-induced apoptosis and DNA damage, the antioxidant NAC was co-treated with CuSO₄. NAC attenuated CuSO₄-induced ROS production, inhibited apoptosis and DNA damage. Furthermore, the spermatogenesis disorder was also abolished in the co-treatment with CuSO₄ and NAC group. Altogether, abovementioned results indicated that CuSO₄-induced spermatogenesis disorder is related to oxidative stress-mediated DNA damage and germ cell apoptosis, impairing male reproductive function.

Expression of cardiac copper chaperone encoding genes and their correlation with cardiac function parameters in goats

Copper deficiency (CuD) is a common cause of oxidative cardiac tissue damage in ruminants. The expression of copper chaperone (Cu-Ch) encoding genes enables an in-depth understanding of copper-associated disorders, but no previous studies have been undertaken to highlight Cu-Ch disturbances in heart tissue in ruminants due to CuD. The current study aimed to investigate the Cu-Ch mRNA expression in the heart of goats after experimental CuD and highlight their relationship with the cardiac measurements. Eleven male goats were enrolled in this study and divided into the control group (n = 4) and CuD group (n = 7), which received copper-reducing dietary regimes for 7 months. Heart function was evaluated by electrocardiography and echocardiography, and at the end of the experiment, all animals were sacrificed and the cardiac tissues were collected for histopathology and quantitative mRNA expression by real-time PCR. In the treatment group, cardiac measurements revealed increased preload and the existence of cardiac dilatation, and significant cardiac tissue damage by histopathology. Also, the relative mRNA expression of Cu-Ch encoding genes; ATP7A, CTr1, LOX, COX17, as well as ceruloplasmin (CP), troponin I3 (TNNI3), glutathione peroxidase (GPX1), and matrix metalloprotease inhibitor (MMPI1) genes were significantly down-regulated in CuD group. There was a significant correlation between investigated genes and some cardiac function measurements; meanwhile, a significant inverse correlation was observed between histopathological score and ATP7B, CTr1, LOX, and COX17. In conclusion, this study revealed that CuD induces cardiac dilatation and alters the mRNA expression of Cu-Ch genes, in addition to TNNI3, GPX1, and MMPI1 that are considered key factors in clinically undetectable CuD-induced cardiac damage in goats which necessitate further studies for feasibility as biomarkers.

Association of Heavy Metals with Overall Mortality in a Taiwanese Population

Previous studies have shown links between heavy metals and many health issues. However, data on the association between heavy metals and mortality in the general population are still limited. Therefore, the aim of this study was to investigate the relationship between heavy metals and overall mortality in the general population. We enrolled 2497 participants (1001 males and 1496 females) living in southern Taiwan, and measured levels of seven heavy metals: lead (Pb) in blood and cadmium (Cd), nickel (Ni), copper (Cu), chromium (Cr), manganese (Mn) and arsenic (As) in urine. The median follow-up period was 41.8 (4-50) months, during which 40 (1.6%) patients died. Compared to the participants who survived, those who died had higher urine Cd, higher urine Cu and lower urine Mn levels. Multivariate analysis showed that high urine Cd (per 1 μg/L; hazard ratio [HR], 1.352; 95% confidence interval [CI], 1.089-1.680; p = 0.006), high urine Cu (per 1 μg/dL; HR, 1.350; 95% CI, 1.151-1.583; p < 0.001), and low urine Mn (per 1 μg/L; HR, 0.717; 95% CI, 0.557-0.923; p = 0.010) were associated with increased overall mortality. In conclusion, our results demonstrated that high levels of urine Cd and Cu and low urine Mn level were associated with increased overall mortality in the general population.

Inclusion of dicopper oxide instead of copper sulfate in diets for growing-finishing pigs results in greater final body weight and bone mineralization, but reduced accumulation of copper in the liver

An experiment was conducted to test the hypothesis that inclusion of Cu oxide (Cu2O) in diets for growing-finishing pigs improves body weight (BW) and bone mineralization, and reduces accumulation of Cu in the liver compared with pigs fed diets containing Cu sulfate (CuSO4). Two hundred growing pigs (initial BW: 11.5 ± 0.98 kg) were allotted to a randomized complete block design with 2 blocks of 100 pigs, 5 dietary treatments, 5 pigs per pen, and a total of 8 pens per treatment. Treatments included the negative control (NC) diet that contained 20 mg Cu/kg, and 4 diets in which 125 or 250 mg Cu/kg from CuSO4 or Cu2O were added to the NC diet. The experiment was divided into 4 phases and concluded when pigs reached market weight. Pig weights were recorded on day 1 and at the end of each phase and feed provisions were recorded throughout the experiment. On the last day of phases 1 and 4, 1 pig per pen was sacrificed to obtain samples of liver and spleen tissue, and the right metacarpal was collected. Results indicated that pigs fed diets containing 250 mg Cu/kg from CuSO4 had greater BW at the end of phases 1 and 2 than pigs fed NC diets. Pigs fed diets containing 250 mg Cu/kg from Cu2O had greater (P < 0.05) BW at the end of phases 1, 2, 3, and 4 compared with pigs fed NC diets, and these pigs also had greater BW at the end of phases 3 and 4 than pigs fed all other diets. Pigs fed the diets with 250 mg Cu/kg tended to have greater (P < 0.10) feed intake than pigs fed the NC diet at the end of phase 2, and for the overall experimental period, pigs fed diets containing 250 mg Cu/kg from Cu2O had greater (P < 0.05) feed intake than pigs on all other treatments. However, no differences in gain:feed ratio were observed among treatments. Copper accumulation in liver and spleen increased with Cu dose, but at the end of phase 1, pigs fed 250 mg Cu/kg from CuSO4 had greater (P < 0.05) Cu concentration in liver and spleen than pigs fed 250 mg Cu/kg from Cu2O. Pigs fed diets containing 250 mg Cu/kg from Cu2O had greater (P < 0.05) quantities of bone ash and greater (P < 0.05) concentrations of Ca, P, and Cu in bone ash than pigs fed NC diets or the 2 diets containing CuSO4, but Zn concentration in bone ash was less (P < 0.05) in pigs fed diets containing 250 mg Cu/kg from Cu2O. To conclude, supplementing diets for growing pigs with Cu2O improves growth performance and bone mineralization with less Cu accumulation in liver compared with pigs fed diets containing CuSO4.

Copper-based biomaterials for bone and cartilage tissue engineering

Backgroud

Tissue engineering using cells, scaffolds, and bioactive molecules can promote the repair and regeneration of injured tissues. Copper is an essential element for the human body that is involved in many physiological activities and in recent years, copper has been used increasingly in tissue engineering.

Methods

The current advances of copper-based biomaterial for bone and cartilage tissue engineering were searched on PubMed and Web of Science.

Results

Various forms of copper-based biomaterials, including pure copper, copper ions, copper nanoparticles, copper oxides, and copper alloy are introduced. The incorporation of copper into base materials provides unique properties, resulting in tuneable porosity, mechanical strength, degradation, and crosslinking of scaffolds. Copper also shows promising biological performance in cell migration, cell adhesion, osteogenesis, chondrogenesis, angiogenesis, and antibacterial activities. In vivo applications of copper for bone and cartilage tissue engineering are discussed.

Conclusion

This review focuses on copper’s physiochemical and biological effects, and its applications in bone and cartilage tissue engineering. The potential limitations and future perspectives are also discussed.

Translational potential of this article

This review introduces the recent advances in copper-based biomaterial for bone and cartilage tissue engineering. This revie could guide researchers to apply copper in biomaterials, improving the generation of bone and cartilages, decrease the possibility of infection and shorten the recovery time so as to decrease medical costs.

mtROS-mediated Akt/AMPK/mTOR pathway was involved in Copper-induced autophagy and it attenuates Copper-induced apoptosis in RAW264.7 mouse monocytes

Copper (Cu) is a trace element necessary in animals as well as human beings. However, excessive Cu is toxic to immunocytes, but the precise mechanism is largely unclear so far. This work was conducted aiming to examine the Cu-mediated autophagy mechanism together with its role in Cu toxicology in RAW264.7 cells. Here, we demonstrated that CuSO4 reduced the cell viability depending on its dose. CuSO4 could obviously increase autophagy in RAW264.7 cells. According to the obtained results, CuSO4 induced autophagy through Akt/AMPK/mTOR pathway which characterized by down regulation of p-Akt (Ser473)/Akt, p-mTOR/mTOR, p-ULK1(Ser757)/ULK1 and subsequent up-regulation of p-AMPKα/AMPKα and p-ULK1(Ser555)/ULK1. Furthermore, CuSO4 significantly induced the production of mitochondrial reactive oxygen species (mtROS). In addition, CuSO4-mediated apoptosis and autophagy might be suppressed through suppressing mtROS generation by exposure to Mito-TEMPO. Intriguingly, autophagy promotion with rapamycin could decrease the apoptosis and the inhibition of autophagy with knock down Atg5 could enhance the apoptosis induced by CuSO4. Moreover, our results suggested that mtROS is the original cause in CuSO4-induced apoptosis and autophagy. Additionally, CuSO4 induced autophagy through mtROS-dependent Akt/AMPK/mTOR signalling pathwayin RAW264.7 cells. Moreover, autophagy activation might potentially generate a protection mechanism for improving CuSO4-induced RAW264.7 cell apoptosis.

Biological applications of copper-containing materials

Copper is an indispensable trace metal element in the human body, which is mainly absorbed in the stomach and small intestine and excreted into the bile. Copper is an important component and catalytic agent of many enzymes and proteins in the body, so it can influence human health through multiple mechanisms. Based on the biological functions and benefits of copper, an increasing number of researchers in the field of biomaterials have focused on developing novel copper-containing biomaterials, which exhibit unique properties in protecting the cardiovascular system, promoting bone fracture healing, and exerting antibacterial effects. Copper can also be used in promoting incisional wounds healing, killing cancer cells, Positron Emission Tomography (PET) imaging, radioimmunological tracing and radiotherapy of cancer. In the present review, the biological functions of copper in the human body are presented, along with an overview of recent progress in our understanding of the biological applications and development of copper-containing materials. Furthermore, this review also provides the prospective on the challenges of those novel biomaterials for future clinical applications.

Immunomodulatory diet in pediatric age

In the last few decades, the importance of a functioning immune system and health status has become more evident. Multiple factors are able to influence the development of chronic diseases and diet is one of the most important environmental factors. Evidence demonstrates that dietary patterns high in fat and low in fiber are associated with the development of non-communicable diseases. Moreover, optimal nutritional status can modulate immune maturation and response to inflammation. During inflammatory conditions, nutritional deficiencies may occur, establishing a vicious circle, consequently a balanced nutritional status is essential to prevent and counteract infections. Dietary diversity can prevent allergic diseases and nutrients such as DHA, arginine, vitamins and trace elements have an impact on physical barriers (such as gut mucosal barrier and skin), on the immune system response and on microbiome modulation. Protein deficiencies can compromise innate and adaptive immune functions; arginine availability can affect the immune response in injured states and other disease processes; EPA and DHA can modulate both innate and adaptive immunity; prebiotics have a beneficial effect on the functioning of the immune system. Zinc, copper, selenium and iron are involved in the correct development and function of the immune system. Vitamins D, E, A, B and C have a role on immune system through different mechanisms of action. Since a complex interplay exists between diet, microbiome and epigenetic factors which determine nutrient-induced changes on the immune function, the effect of each single nutrient may be difficult to study. Well-designed intervention studies, investigating the effects of whole dietary pattern, should be performed to clarify impact of foods on the immune function and disease risk.

The utility of electrocardiography and echocardiography in copper deficiency-induced cardiac damage in goats

Copper deficiency (CuD) is a common mineral disorder in ruminants, which causes histomorphological changes in the heart due to disturbances in copper-dependent metalloenzymes. However, alterations in the measurable cardiac parameters during CuD have not been studied in ruminants, especially in goats. Therefore, the current study aimed to investigate longitudinally the potential role of electrocardiography (ECG) and echocardiography to detect the CuD-induced cardiac damage at different time intervals and concomitantly highlighting the impact of CuD on specific hemato-biochemical parameters and histological cardiac disruption in goats. Eight Shiba goats were included and divided into two equal groups; copper adequate (CuA) as a control and copper-deficient (CuD) that supplemented with copper-chelating agents (sulfur 3 g/kg DM and molybdenum 40 mg/kg DM). The hemato-biochemical analysis, ECG assessment at the base apex lead, and right-side echocardiography were performed just before the experimental onset (T0), and later on at two-time intervals after existing of CuD, at the fifth (T5) and seventh (T7) months. Necropsy and histopathological examination of the heart were performed at the end of the experiment. In the CuD group, the heart dimensions at T5 and T7 showed significant increase in QRS duration, ST-segment duration, the left atrial area in systole, left ventricular diameter and volume in diastole, stroke volume, and cardiac output compared with CuA (P < 0.05). Also, myocardial degeneration, necrosis, and fibrosis were evidenced with a concurrent increase of plasma creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and cardiac troponin I (P < 0.05). In conclusion, CuD disturbs hemato-biochemical parameters and results in myocardial damage and cardiac dilatation that increases some ECG and echocardiographic parameters without development of systolic dysfunction. The ECG and echocardiography can potentially detect cardiac changes in long-lasting CuD in goats.

Profile of copper-associated DNA methylation and its association with incident acute coronary syndrome

Background

Acute coronary syndrome (ACS) is a cardiac emergency with high mortality. Exposure to high copper (Cu) concentration has been linked to ACS. However, whether DNA methylation contributes to the association between Cu and ACS is unclear.

Methods

We measured methylation level at > 485,000 cytosine-phosphoguanine sites (CpGs) of blood leukocytes using Human Methylation 450 Bead Chip and conducted a genome-wide meta-analysis of plasma Cu in a total of 1243 Chinese individuals. For plasma Cu-related CpGs, we evaluated their associations with the expression of nearby genes as well as major cardiovascular risk factors. Furthermore, we examined their longitudinal associations with incident ACS in the nested case-control study.

Results

We identified four novel Cu-associated CpGs (cg20995564, cg18608055, cg26470501 and cg05825244) within a 5% false discovery rate (FDR). DNA methylation level of cg18608055, cg26470501, and cg05825244 also showed significant correlations with expressions of SBNO2, BCL3, and EBF4 gene, respectively. Higher DNA methylation level at cg05825244 locus was associated with lower high-density lipoprotein cholesterol level and higher C-reactive protein level. Furthermore, we demonstrated that higher cg05825244 methylation level was associated with increased risk of ACS (odds ratio [OR], 1.23; 95% CI 1.02–1.48; P = 0.03).

Conclusions

We identified novel DNA methylation alterations associated with plasma Cu in Chinese populations and linked these loci to risk of ACS, providing new insights into the regulation of gene expression by Cu-related DNA methylation and suggesting a role for DNA methylation in the association between copper and ACS.

Copper nanoparticles: Biosynthesis, characterization, and protoscolicidal effects alone and combined with albendazole against hydatid cyst protoscoleces

BACKGROUND

Surgery remains the preferred treatment option for hydatid cyst (cystic echinococcosis); however, recent studies have demonstrated that the current protoscolicidal agents used during surgery are associated with some adverse side effects such as biliary fibrosis, hepatic necrosis, and cirrhosis. The present study aims to evaluate the in vitro and ex vivo anti-parasitic effects of copper nanoparticles (CuNPs) alone and combined with albendazole on hydatid cyst protoscoleces.

METHODS

CuNPs was green synthesized using C. spinosa extract. Various concentrations of CuNPs (250, 500, and 750 mg/mL) alone and combined with albendazole (ALZ, 200 mg/mL) were exposed to protoscoleces collected from the liver fertile hydatid cysts of infected sheep for 5-60 min in vitro and ex vivo. Next, the eosin exclusion test was applied to determine the viability of protoscoleces. Caspase-3 like activity of CuNPs-treated protoscoleces was then evaluated using the colorimetric protease assay Sigma Kit based on the manufacturer's instructions.

RESULTS

Scanning electron microscopy (SEM) results showed that the particle size of CuNPs was 17 and 41 nm with the maximum peak at the wavelength of 414 nm. The maximum protoscolicidal activity of CuNPs was observed at the concentration of 750 mg/mL in vitro, so that 73.3 % of protoscoleces were killed after 60 min of exposure. Meanwhile, the mortality of protoscoleces was 100 % after 10 min of exposure to 750 mg/mL of CuNPs along with ALZ (200 mg/mL). Nevertheless, the findings proved that CuNPs even in combination with ALZ required a longer time to kill protoscoleces ex vivo. After 48 h of treating protoscoleces, CuNPs in a dose-dependent manner and at doses of 250, 500, and 750 mg/mL induced the caspase enzyme activation by 20.5 %, 32.3 %, and 36.1 %, respectively.

CONCLUSION

The findings of the present investigation showed potent protoscolicidal effects of CuNPs, especially combined with albendazole, which entirely eliminated the parasite after 10-20 min of exposure. The results also showed that although the possible protoscolicidal mechanisms of CuNPs are not clearly understood, the inducing apoptosis through caspases is one of the main protoscolicidal mechanisms of CuNPs. However, supplementary studies, especially in animal models and clinical settings, are needed to approve these results.

Effects of two zinc supplementation levels and two zinc and copper sources with different solubility characteristics on the growth performance, carcass characteristics and digestibility of growing-finishing pigs

The present study was conducted to evaluate the effect of two Zn supplemented levels and two Zn and Cu sources (sulphate and hydroxychloride) on growing-finishing pigs. An in vitro study and an in vivo study were conducted. In the in vitro study, Zn solubility from each source at different Zn supplementation levels was evaluated, as well as the phytic phosphorus (PP) solubility derived from the interaction or not with phytic acid at similar conditions to those found in digestive tract. The most critical interaction of Zn with phytic acid was at pH 6.5 and with Zn sulphate, resulting in the reduction in PP solubility. In the in vivo experiment, a total of 444 pigs ([Duroc × Landrace]×Pietrain; initial BW: 18.7 ± 0.20 kg) were allotted to 36 pens in a randomized complete block design (2 × 2) factorial arrangement with two Zn and Cu sources and two Zn supplemental levels (20 and 80 mg/kg). The Cu supplementation was fixed at 15 mg/kg for all diets. There was no effect of the interaction between mineral source × Zn level or Zn level on growth performance or carcass characteristics (p > .10). Apparent total digestibility of Zn and Cu along with carcass yield was higher for pigs fed hydroxychloride than pigs fed the sulphate counterparts (p < .05). Feeding low levels of Zn decreased Zn (45.5%; p < .0001) and Cu(18.5%; p = .018) faecal excretion. In conclusion, under commercial conditions, feeding growing-finishing pigs with Zn levels below those established by the European Union regulation did not affect growth performance and carcass characteristics. Reducing dietary mineral (Zn and Cu) diet content resulted in a lower faecal mineral excretion. Pigs fed sulphate minerals had an improved performance during grower period, while pigs fed hydroxychloride minerals showed an improved performance during finishing period and a greater carcass yield and mineral digestibility than those fed sulphates.

Copper homeostasis: Emerging target for cancer treatment

Copper (Cu) is an essential micronutrient involved in a variety of fundamental biological processes. Recently, disorder of Cu homeostasis can be observed in many malignancies. Elevated Cu levels in serum and tissue are correlated with cancer progression. Hence, targeting Cu has emerged as a novel strategy in cancer treatment. This review provides an overview of physiological Cu metabolism and its homeostasis, followed by a discussion of the dysregulation of Cu homeostasis in cancer and the effects of Cu on cancer progression. Finally, recent therapeutic advances using Cu coordination complexes as anticancer agents, as well as the mechanisms of their anti-cancer action are discussed. This review contributes full comprehension to the role of Cu in cancer and demonstrates the broad application prospect of Cu coordination compounds as potential therapeutic agents.

Chronic Copper Exposure Induces Hypospermatogenesis in Mice by Increasing Apoptosis Without Affecting Testosterone Secretion

Chronic copper exposure impaired spermatogenesis in adult male mice. The aim of this study was to determine whether chronic copper exposure can induce apoptosis of testicular cell and hypospermatogenesis via disturbing testosterone synthesis in adult male mice. In the present study, sixty CD-1 male mice were randomly divided into four groups, and were continuously administered for 8 weeks by oral gavage with copper sulfate at a dose of 0, 25, 100, and 150 mg/kg/day, respectively. We determined the content of serum and testicular copper, testicular coefficient, testicular histopathology, sperm count and motility, the mRNA and protein levels of Caspase-3, Bax, and Bcl-2, Leydig cell count, testosterone content, testosterone synthetase, and testosterone synthesis-related genes. The results showed that the copper levels in serum increased in a dose-dependent manner, and the copper levels in testes were significantly related to serum copper levels. Male mice given copper sulfate 100 and 150 dosage groups showed significant decreased in sperm motility and sperm number as well as increased in testes damage, and there was no significant change in testicular coefficient in the four groups. The mRNA levels of Bcl-2 decreased and Caspase-3 increased in 150 dosage group, and Bax increased in two higher dosage groups. Meanwhile, Caspase-3 and Bax proteins increased in 150 dosage group, and Bcl-2 protein decreased in three copper treatment groups. Nevertheless, there were no differences on the levels of testosterone content and testosterone synthetase of 3β-HSD, 17β-HSD, 17α-Hyd, and 20α-Hyd, mRNA levels of Cyp11a1, Cyp17a1, and Star, and quantity of Leydig cells in four groups. Overall, these data showed that chronic copper exposure led to copper residues in the testes, and the doses of 100 and 150 mg/kg/day copper sulfate may induce hypospermatogenesis by increasing apoptosis without affecting testosterone secretion.

Functional analyses of copper transporter genes in the human liver cell line HepG2

Copper (Cu) is an essential element regulated by four genes (hCTR1, hATOX1, hATP7A, and hATP7B in humans and zctr1, zatox1, zatp7a, and zatp7b in zebrafish) in copper uptake, distribution, and transport in animal cells. Zebrafish (Danio rerio) shows a higher endogenous ratio of zatp7a to zatp7b in the liver, is relatively intolerant to copper ions and has a different zatp7a and zatp7b expression patterns in different organs. As high-affinity copper transporters, both zctr1 and hCTR1 increased copper toxicity, whereas hATOX1 and zatox1 slightly reduced copper toxicity in HepG2 cells after copper administration for 24 h. The transfected zatp7b functioned in HepG2 cells as effectively as hATP7B after both 24-h and 96-h copper exposure, but zatp7a failed to function in HepG2 cells as effectively as hATP7A. Our findings suggest that ATP7A dysfunction would increase cytotoxicity in the liver; the reason for zebrafish's copper intolerance could be the bulk dysfunction and abnormal localization of zATP7A.

The level of microelements and heterogeneity of joint hypermobility as an endophenotype of undifferentiated connective tissue dysplasia

Objective — The aim of the work was to study serum concentrations of magnesium, copper, zinc, phosphorus and calcium in individuals with undifferentiated connective tissue dysplasia (uCTD) and joint hypermobility (JH) in an isolated and combined state. Material and methods — the concentrations of magnesium, copper, zinc, phosphorus and calcium were measured by the direct colorimetric method in 55 people with joint hypermobility and in 34 – without hypermobility. Results — There were no significant differences between serum concentrations of microelementsin groups with and without JH. In patients with mild and severe uCTD significant decrease in serum magnesium concentrations was noted (U=2.12, p=0.034 and U=3.7, p=0.012). In patients with isolated JH significant serum zinc concentrationdecrease was revealed compared with the control group (U=3.12, p=0.022). Serum magnesium concentrations were reduced in all patients with uCTD and JH; in the groups with isolated dysplasia and combined pathology, the differences reached the level of statistical significance (U=2.78, p=0.024 and U=3.2, p=0.018). Conclusion — The study revealed significant associations of a decrease in serum magnesium concentrations with the development of uCTD in an isolated and combined with JH state and decrease in serum zinc concentrations with the development of isolated JH.