Dietary copper supplementation reverses hypertrophic cardiomyopathy induced by chronic pressure overload in mice

Cuproptosis and copper deficiency in ischemic vascular injury and repair

Ischemic vascular diseases are on the rise globally, including ischemic heart diseases, ischemic cerebrovascular diseases, and ischemic peripheral arterial diseases, posing a significant threat to life. Copper is an essential element in various biological processes, copper deficiency can reduce blood vessel elasticity and increase platelet aggregation, thereby increasing the risk of ischemic vascular disease; however, excess copper ions can lead to cytotoxicity, trigger cell death, and ultimately result in vascular injury through several signaling pathways. Herein, we review the role of cuproptosis and copper deficiency implicated in ischemic injury and repair including myocardial, cerebral, and limb ischemia. We conclude with a perspective on the therapeutic opportunities and future challenges of copper biology in understanding the pathogenesis of ischemic vascular disease states.

Cuproptosis and Cu: a new paradigm in cellular death and their role in non-cancerous diseases

Cuproptosis, a newly characterized form of regulated cell death driven by copper accumulation, has emerged as a significant mechanism underlying various non-cancerous diseases. This review delves into the complex interplay between copper metabolism and the pathogenesis of conditions such as Wilson's disease (WD), neurodegenerative disorders, and cardiovascular pathologies. We examine the molecular mechanisms by which copper dysregulation induces cuproptosis, highlighting the pivotal roles of key copper transporters and enzymes. Additionally, we evaluate the therapeutic potential of copper chelation strategies, which have shown promise in experimental models by mitigating copper-induced cellular damage and restoring physiological homeostasis. Through a comprehensive synthesis of recent advancements and current knowledge, this review underscores the necessity of further research to translate these findings into clinical applications. The ultimate goal is to harness the therapeutic potential of targeting cuproptosis, thereby improving disease management and patient outcomes in non-cancerous conditions associated with copper dysregulation.

Copper toxicity and deficiency: the vicious cycle at the core of protein aggregation in ALS

The pathophysiology of ALS involves many signs of a disruption in copper homeostasis, with both excess free levels and functional deficiency likely occurring simultaneously. This is crucial, as many important physiological functions are performed by cuproenzymes. While it is unsurprising that many ALS symptoms are related to signs of copper deficiency, resulting in vascular, antioxidant system and mitochondrial oxidative respiration deficiencies, there are also signs of copper toxicity such as ROS generation and enhanced protein aggregation. We discuss how copper also plays a key role in proteostasis and interacts either directly or indirectly with many of the key aggregate-prone proteins implicated in ALS, such as TDP-43, C9ORF72, SOD1 and FUS as well as the effect of their aggregation on copper homeostasis. We suggest that loss of cuproprotein function is at the core of ALS pathology, a condition that is driven by a combination of unbound copper and ROS that can either initiate and/or accelerate protein aggregation. This could trigger a positive feedback cycle whereby protein aggregates trigger the aggregation of other proteins in a chain reaction that eventually captures elements of the proteostatic mechanisms in place to counteract them. The end result is an abundance of aggregated non-functional cuproproteins and chaperones alongside depleted intracellular copper stores, resulting in a general lack of cuproenzyme function. We then discuss the possible aetiology of ALS and illustrate how strong risk factors including environmental toxins such as BMAA and heavy metals can functionally behave to promote protein aggregation and disturb copper metabolism that likely drives this vicious cycle in sporadic ALS. From this synthesis, we propose restoration of copper balance using copper delivery agents in combination with chaperones/chaperone mimetics, perhaps in conjunction with the neuroprotective amino acid serine, as a promising strategy in the treatment of this incurable disease.

Reversal of atherosclerosis by restoration of vascular copper homeostasis

Atherosclerosis has traditionally been considered as a disorder characterized by the accumulation of cholesterol and thrombotic materials within the arterial wall. However, it is now understood to be a complex inflammatory disease involving multiple factors. Central to the pathogenesis of atherosclerosis are the interactions among monocytes, macrophages, and neutrophils, which play pivotal roles in the initiation, progression, and destabilization of atherosclerotic lesions. Recent advances in our understanding of atherosclerosis pathogenesis, coupled with results obtained from experimental interventions, lead us to propose the hypothesis that atherosclerosis may be reversible. This paper outlines the evolution of this hypothesis and presents corroborating evidence that supports the potential for atherosclerosis regression through the restoration of vascular copper homeostasis. We posit that these insights may pave the way for innovative therapeutic approaches aimed at the reversal of atherosclerosis.

Copper incorporated biomaterial-based technologies for multifunctional wound repair

The treatment of wounds is a worldwide challenge, and wound infection can affect the effectiveness of wound treatment and further increase the disease burden. Copper is an essential trace element that has been shown to have broad-spectrum antibacterial effects and to be involved in the inflammation, proliferation, and remodeling stages of wound healing. Compared to treatments such as bioactive factors and skin grafts, copper has the advantage of being low-cost and easily available, and has received a lot of attention in wound healing. Recently, biomaterials made by incorporating copper into bioactive glasses, polymeric scaffolds and hydrogels have been used to promote wound healing by the release of copper ions. In addition, copper-incorporated biomaterials with catalytic, photothermal, and photosensitive properties can also accelerate wound healing through antibacterial and wound microenvironment regulation. This review summarizes the antibacterial mechanisms of copper- incorporated biomaterials and their roles in wound healing, and discusses the current challenges. A comprehensive understanding of the role of copper in wounds will help to facilitate new preclinical and clinical studies, thus leading to the development of novel therapeutic tools.

A new insight on copper: Promotion of collagen synthesis and myofiber growth and development in juvenile grass carp (Ctenopharyngodon idella)

Copper (Cu) is a trace element, essential for fish growth. In the current study, in addition to growth performance, we first explored the effects of Cu on collagen synthesis and myofiber growth and development in juvenile grass carp (Ctenopharyngodon idella). A total of 1080 fish (11.16 ± 0.01 g) were randomly divided into 6 treatments (3 replicates per treatment) to receive five doses of organic Cu, which were Cu citrate (CuCit) at 0.99 (basal diet), 2.19, 4.06, 6.15, and 8.07 mg/kg, and one dose of inorganic Cu (CuSO4·5H2O at 3.15 mg/kg), for 9 weeks. The results showed appropriate Cu level (4.06 mg/kg) enhanced growth performance, improved nutritional Cu status, and downregulated Cu-transporting ATPase 1 mRNA levels in the hepatopancreas, intestine, and muscle of juvenile grass carp. Meanwhile, collagen content in fish muscle was increased after Cu intake, which was probably due to the following pathways: (1) activating CTGF/TGF-β1/Smads signaling pathway to regulate collagen transcription; (2) upregulating of La ribonucleoprotein domain family 6 (LARP6) mRNA levels to regulate translation initiation; (3) increasing proline hydroxylase, lysine hydroxylase, and lysine oxidase activities to regulate posttranslational modifications. In addition, optimal Cu group increased myofiber diameters and the frequency of myofibers with diameter >50 μm, which might be associated with upregulation of cyclin B, cyclin D, cyclin E, proliferating cell nuclear antigen, myogenic determining factor (MyoD), myogenic factor 5, myogenin (MyoG), myogenic regulatory factor 4 and myosin heavy chain (MyHC) and downregulation of myostatin mRNA levels, increasing protein levels of MyoD, MyoG and MyHC in fish muscle. Finally, based on percentage weight gain (PWG), serum ceruloplasmin (Cp) activity and collagen content in fish muscle, Cu requirements were determined as 4.74, 4.37 and 4.62 mg/kg diet (CuCit as Cu source) of juvenile grass carp, respectively. Based on PWG and Cp activity, compared to CuSO4·5H2O, the efficacy of CuCit were 131.80% and 115.38%, respectively. Our findings provide new insights into Cu supplementation to promote muscle growth in fish, and help improve the overall productivity of aquaculture.

Role of copper and its complexes in cardiovascular diseases

Copper is a trace element essential for the maintenance of normal physiological functions in cardiovascular system, and its transport and metabolisms are regulated by various copper proteins such as copper-based enzymes, copper chaperones and copper transporters. The disturbance of copper level or abnormal expression of copper proteins are closely associated with the development of cardiovascular diseases such as atherosclerosis, hypertension, ischemic heart disease, myocardial hypertrophy and heart failure. Thus, intervention of copper ion signaling pathways is expected to be an effective measure for treating cardiovascular diseases. Some copper complexes, such as trientine, copper-aspirinate complex and copper (II) diethyldithiocarbamate, have been found to play a role in the prevention and treatment of cardiovascular diseases and possess potential prospects. Exploring the role of copper in maintaining normal cardiovascular status and the potential application of copper complexes in the treatment of cardiovascular diseases may lay a foundation for finding new targets for prevention and treatment of various cardiovascular diseases, and provide new ideas for clinical treatment of cardiovascular diseases.

Transition metals in angiogenesis - A narrative review

The aim of this paper is to offer a narrative review of the literature regarding the influence of transition metals on angiogenesis, excluding lanthanides and actinides. To our knowledge there are not any reviews up to date offering such a summary, which inclined us to write this paper. Angiogenesis describes the process of blood vessel formation, which is an essential requirement for human growth and development. When the complex interplay between pro- and antiangiogenic mediators falls out of balance, angiogenesis can quickly become harmful. As it is so fundamental, both its inhibition and enhancement take part in various diseases, making it a target for therapeutic treatments. Current methods come with limitations, therefore, novel agents are constantly being researched, with metal agents offering promising results. Various transition metals have already been investigated in-depth, with studies indicating both pro- and antiangiogenic properties, respectively. The transition metals are being applied in various formulations, such as nanoparticles, complexes, or scaffold materials. Albeit the increasing attention this field is receiving, there remain many unanswered questions, mostly regarding the molecular mechanisms behind the observed effects. Notably, approximately half of all the transition metals have not yet been investigated regarding potential angiogenic effects. Considering the promising results which have already been established, it should be of great interest to begin investigating the remaining elements whilst also further analyzing the established effects.

Three-dimensional spatial quantitative analysis of cardiac lymphatics in the mouse heart

OBJECTIVE

Three-dimensional (3D) microscopy and image data analysis are necessary for studying the morphology of cardiac lymphatic vessels (LyVs) and their association with other cell types. We aimed to develop a methodology for 3D multiplexed lightsheet microscopy and highly sensitive and quantitative image analysis to identify pathological remodeling in the 3D morphology of LyVs in young adult mouse hearts with familial hypertrophic cardiomyopathy (HCM).

METHODS

We developed a 3D lightsheet microscopy workflow providing a quick turn-around (as few as 5-6 days), multiplex fluorescence detection, and preservation of LyV structure and epitope markers. Hearts from non-transgenic and transgenic (TG) HCM mice were arrested in diastole, retrograde perfused, immunolabeled, optically cleared, and imaged. We built an image-processing pipeline to quantify LyV morphological parameters at the chamber and branch levels.

RESULTS

Chamber-specific pathological alterations of LyVs were identified, and significant changes were seen in the right atrium (RA). TG hearts had a higher volume percent of ER-TR7+ fibroblasts and reticular fibers. In the RA, we found associations between ER-TR7+ volume percent and both LyV segment density and median diameter.

CONCLUSIONS

This workflow and study enabled multi-scale analysis of pathological changes in cardiac LyVs of young adult mice, inviting ideas for research on LyVs in cardiac disease.

Exploring cuproptosis as a mechanism and potential intervention target in cardiovascular diseases

Copper (Cu) is a vital trace element for maintaining human health. Current evidence suggests that genes responsible for regulating copper influx and detoxification help preserve its homeostasis. Adequate Cu levels sustain normal cardiac and blood vessel activity by maintaining mitochondrial function. Cuproptosis, unlike other forms of cell death, is characterized by alterations in mitochondrial enzymes. Therapeutics targeting cuproptosis in cardiovascular diseases (CVDs) mainly include copper chelators, inhibitors of copper chaperone proteins, and copper ionophores. In this review, we expound on the primary mechanisms, critical proteins, and signaling pathways involved in cuproptosis, along with its impact on CVDs and the role it plays in different types of cells. Additionally, we explored the influence of key regulatory proteins and signaling pathways associated with cuproptosis on CVDs and determined whether intervening in copper metabolism and cuproptosis can enhance the outcomes of CVDs. The insights from this review provide a fresh perspective on the pathogenesis of CVDs and new targets for intervention in these diseases.

hsa-mir-(4328, 4422, 548z and -628-5p) in diabetic retinopathy: diagnosis, prediction and linking a new therapeutic target

AIMS

Growing evidence suggests that microRNAs (miRNAs) are crucial in controlling how diabetic retinopathy (DR) develops. We intend to mine miRNAs with diagnostic and predictive value for DR and to investigate new drug therapeutic targets.

METHODS

After performing a differential analysis on the miRNA and mRNA datasets for DR and neovascularization (NEO), miRNA-mRNA networks were created. Combine the results of enrichment analysis, Protein-Protein Interaction Networks (PPI), and Cytoscape to identify key miRNAs. DrugBank was used to find drugs that interacted with transcription factors (TF) predicted by TransmiR. Finally, whole blood and clinical data were collected from 58 patients with type 2 diabetes mellitus (T2DM), and RT-qPCR, logistic analysis, and ROC were used to verify the value of key miRNAs.

RESULTS

Differential analysis indicated the presence of genes and miRNAs that co-regulate DR and NEO. Enrichment analysis showed that key genes are inextricably linked to neovascularization. Combining the results of PPI and Cytoscape identified four key miRNAs, namely hsa-mir-(4328, 4422, 548z and -628-5p). RT-qPCR, logistic, and ROC results showed that decreased expression levels of hsa-mir-(4328, 4422, 548z and -628-5p) signal the risk of evolution to DR in T2DM patients. Finally, we constructed a TF-miRNA network to find the 15 TFs and the 35 drugs that interact with these TFs.

CONCLUSION

hsa-mir-(4328, 4422, 548z and -628-5p) in whole blood are protective factors for DR as novel biomarkers for diagnosis and prediction. In addition, our research provides new drug directions for the treatment of DR, such as Diosmin, Atorvastatin, and so on.

Three-dimensional spatial quantitative analysis of cardiac lymphatics in the mouse heart

Objective

3D microscopy and image data analysis are necessary for studying the morphology of cardiac lymphatic vessels (LyVs) and association with other cell types. We aimed to develop a methodology for 3D multiplexed lightsheet microscopy and highly sensitive and quantitative image analysis to identify pathological remodeling in the 3D morphology of LyVs in young adult mouse hearts with familial hypertrophic cardiomyopathy (HCM).

Methods

We developed a 3D lightsheet microscopy workflow providing a quick turn-around (as few as 5-6 days), multiplex fluorescence detection, and preservation of LyV structure and epitope markers. Hearts from non-transgenic (NTG) and transgenic (TG) HCM mice were arrested in diastole, retrograde perfused, immunolabeled, optically cleared, and imaged. We built an image processing pipeline to quantify LyV morphological parameters at the chamber and branch levels.

Results

Chamber-specific pathological alterations of LyVs were identified, but most significantly in the right atrium (RA). TG hearts had a higher volume fraction of ER-TR7 + fibroblasts and reticular fibers. In the RA, we found associations between ER-TR7 + volume fraction and both LyV segment density and median diameter.

Conclusions

This workflow and study enabled multi-scale analysis of pathological changes in cardiac LyVs of young adult mice, inviting ideas for research on LyVs in cardiac disease.

Cardiac copper content and its relationship with heart physiology: Insights based on quantitative genetic and functional analyses using BXD family mice

Background

Copper (Cu) is essential for the functioning of various enzymes involved in important cellular and physiological processes. Although critical for normal cardiac function, excessive accumulation, or deficiency of Cu in the myocardium is detrimental to the heart. Fluctuations in cardiac Cu content have been shown to cause cardiac pathologies and imbalance in systemic Cu metabolism. However, the genetic basis underlying cardiac Cu levels and their effects on heart traits remain to be understood. Representing the largest murine genetic reference population, BXD strains have been widely used to explore genotype-phenotype associations and identify quantitative trait loci (QTL) and candidate genes.

Methods

Cardiac Cu concentration and heart function in BXD strains were measured, followed by QTL mapping. The candidate genes modulating Cu homeostasis in mice hearts were identified using a multi-criteria scoring/filtering approach.

Results

Significant correlations were identified between cardiac Cu concentration and left ventricular (LV) internal diameter and volumes at end-diastole and end-systole, demonstrating that the BXDs with higher cardiac Cu levels have larger LV chamber. Conversely, cardiac Cu levels negatively correlated with LV posterior wall thickness, suggesting that lower Cu concentration in the heart is associated with LV hypertrophy. Genetic mapping identified six QTLs containing a total of 217 genes, which were further narrowed down to 21 genes that showed a significant association with cardiac Cu content in mice. Among those, Prex1 and Irx3 are the strongest candidates involved in cardiac Cu modulation.

Conclusion

Cardiac Cu level is significantly correlated with heart chamber size and hypertrophy phenotypes in BXD mice, while being regulated by multiple genes in several QTLs. Prex1 and Irx3 may be involved in modulating Cu metabolism and its downstream effects and warrant further experimental and functional validations.

Copper promotes cardiac functional recovery via suppressing the transformation of fibroblasts to myofibroblasts in ischemia-infarcted monkey hearts

Myocardial ischemia leads to cardiac fibrosis along with copper (Cu) loss. Cu repletion diminishes myocardial fibrosis and improves cardiac function. The transformation of fibroblasts to myofibroblasts is highly responsible for the pathogenesis of cardiac fibrosis. This study was undertaken to test the hypothesis that Cu inhibition of cardiac fibrosis results from suppression of myofibroblasts. Rhesus monkeys 4-5 years old were subjected to coronary artery ligation to induce myocardial infarction (MI). At the end of the fourth week after the surgery, an ultrasound-directed Cu-albumin microbubble organ-specific Cu delivery technique was used to treat the ischemia-infarcted monkey hearts twice a week for 4 weeks. This treatment increased Cu concentrations in the infarct area, loosened the collagen cross-linking network, restored blood vessel density, and improved cardiac contractility. Total fibroblasts labeled with vimentin were increased in the infarct area, and Cu repletion did not alter this increase. Myofibroblasts, dually labeled with vimentin and α-smooth muscle actin (α-SMA), were also significantly increased in the infarct area but were significantly reduced by Cu repletion. Correspondingly, the products of myofibroblasts, type I and III collagens and inhibitors of collagenases were significantly reduced. In contrast, metalloproteinase-1 (MMP-1) and MMP-1 producing fibroblasts (vimentin⁺ and MMP-1⁺ cells) were significantly increased. These results suggest that Cu inhibits the transformation of fibroblasts to myofibroblasts, leading to a pro-fibrinolytic switch and an improvement in cardiac function.

Essential microelement (copper, selenium, zinc) status according to age and sex in healthy cats

Although domestic cats are one of the most popular companion animals, current knowledge on the fate of micronutrients in cats according to their age, sex, and health is very limited. In this study, 72 whole blood and 54 plasma samples from cats of different ages and sex were collected at three veterinary offices in the Czech Republic, and the copper (Cu), selenium (Se), and zinc (Zn) concentrations were determined using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that Cu was significantly (P < 0.05) higher in both plasma and whole blood of males (980 and 958 μg L-1 in plasma and whole blood, respectively) than in females (741 and 766 μg L-1 in plasma and whole blood, respectively), whereas no significant differences between males and females were found for Se and Zn. Similarly, no significant differences were recorded for any of the three elements according to age, although animals older than 7 years tended to have lower plasma concentrations of all three elements. Hypertrophic cardiomyopathy (HCM) is one of the most prevalent diseases of domestic cats. The potential relationship between the essential microelement status in the blood of cats with HCM vs. cats with no clinical signs of HCM was taken into account, but the limited number of HCM-positive individuals did not allow any clear conclusion. Thus, the potential relationships between micronutrient status in cats and the incidence of HCM should be elucidated in further research.

Copper homeostasis and cuproptosis in health and disease

As an essential micronutrient, copper is required for a wide range of physiological processes in virtually all cell types. Because the accumulation of intracellular copper can induce oxidative stress and perturbing cellular function, copper homeostasis is tightly regulated. Recent studies identified a novel copper-dependent form of cell death called cuproptosis, which is distinct from all other known pathways underlying cell death. Cuproptosis occurs via copper binding to lipoylated enzymes in the tricarboxylic acid (TCA) cycle, which leads to subsequent protein aggregation, proteotoxic stress, and ultimately cell death. Here, we summarize our current knowledge regarding copper metabolism, copper-related disease, the characteristics of cuproptosis, and the mechanisms that regulate cuproptosis. In addition, we discuss the implications of cuproptosis in the pathogenesis of various disease conditions, including Wilson's disease, neurodegenerative diseases, and cancer, and we discuss the therapeutic potential of targeting cuproptosis.

Dietary copper intake and risk of myocardial infarction in US adults: A propensity score-matched analysis

Objectives

Most studies have examined the association between serum copper and myocardial infarction, but there is little evidence of the association between dietary copper intake and myocardial infarction.

Materials and methods

The study included a total of 14,876 participants from the 2011 to 2018 National Health and Nutrition Examination Survey (NHANES). Multivariate logistic regression model was used to analyze the association between dietary copper intake and the risk of myocardial infarction. To reduce selection bias, we use nearest neighbor propensity score matching (PSM) in a 1:2 ratio. Restricted cubic spline (RCS) method is used to study the non-linear relationship. Subgroup stratification was used to further investigate the association between copper intake and myocardial infarction.

Results

The median dietary copper intake was 1.0825 mg/day. A myocardial infarction had occurred in approximately 4.4% (655) of the participants. Before and after matching, multivariate logistic regression models revealed a negative correlation between dietary copper intake and the risk of myocardial infarction. The higher quartile of subjects had a noticeably lower risk of myocardial infarction in comparison to those in the first quartile of copper intake. According to RCS findings, dietary copper intake and myocardial infarction have a non-linear and dose-response relationship. According to stratified analysis, the dietary copper intake was a substantial protective element for those who were ≥ 50 years old, female, 25 ≤BMI <30, with history of smoking, hypertension, diabetes and ortholiposis.

Conclusion

Increased dietary copper intake was associated with a lower risk of myocardial infarction. It is especially significant in elderly-aged women, overweight individuals, smokers, hypertension, and diabetic patients.

Role of Trientine in Hypertrophic Cardiomyopathy: A Review of Mechanistic Aspects

Abnormality in myocardial copper homeostasis is believed to contribute to the development of cardiomyopathy. Trientine, a copper-chelating drug used in the management of patients with Wilson's disease, demonstrates beneficial effects in patients with hypertrophic cardiomyopathy. This review aims to present the updated development of the roles of trientine in hypertrophic cardiomyopathy. The drug has been demonstrated in animal studies to restore myocardial intracellular copper content. However, its mechanisms for improving the medical condition remain unclear. Thus, comprehending its mechanistic aspects in cardiomyopathy is crucial and could help to expedite future research.

Natural Herbal Medicine as a Treatment Strategy for Myocardial Infarction through the Regulation of Angiogenesis

Methods

We conducted a literature search on the bioactive components of medicinal plants and their effects on angiogenesis after MI. We searched for articles in Web of Science, MEDLINE, PubMed, Scopus, Google Scholar, and China National Knowledge Infrastructure databases before April 2021.

Results

In this article, we summarized the mechanisms by which copper ions, microRNA, Akt1, inflammation, oxidative stress, mitochondria, and pericytes are involved in angiogenesis after myocardial infarction. In addition, we reviewed the angiogenic effects of natural herbal medicines such as Salvia miltiorrhiza Bunge Bunge, Carthamus tinctorius L., Pueraria lobata, Astragalus, Panax ginseng C.A. Mey., Panax notoginseng (Burkill) F.H. Chen, Cinnamomum cassia (L.) J. Presl, Rehmannia glutinosa (Gaertn.) DC., Leonurus japonicus Houtt, Scutellaria baicalensis Georgi., and Geum macrophyllum Willd.

Conclusions

Some herbs have the effect of promoting angiogenesis. In the future, natural proangiogenic drugs may become candidates for the treatment of cardiovascular diseases.

An Emerging Role of Defective Copper Metabolism in Heart Disease

Copper is an essential trace metal element that significantly affects human physiology and pathology by regulating various important biological processes, including mitochondrial oxidative phosphorylation, iron mobilization, connective tissue crosslinking, antioxidant defense, melanin synthesis, blood clotting, and neuron peptide maturation. Increasing lines of evidence obtained from studies of cell culture, animals, and human genetics have demonstrated that dysregulation of copper metabolism causes heart disease, which is the leading cause of mortality in the US. Defects of copper homeostasis caused by perturbed regulation of copper chaperones or copper transporters or by copper deficiency resulted in various types of heart disease, including cardiac hypertrophy, heart failure, ischemic heart disease, and diabetes mellitus cardiomyopathy. This review aims to provide a timely summary of the effects of defective copper homeostasis on heart disease and discuss potential underlying molecular mechanisms.

Resuscitating the Field of Cardiac Regeneration: Seeking Answers from Basic Biology

Heart failure (HF) is one of the leading causes for hospital admissions worldwide. HF patients are classified based on the chronic changes in left ventricular ejection fraction (LVEF) as preserved (LVEF ≥ 50%), reduced (LVEF ≤ 40%), or mid-ranged (40% < LVEF < 50%) HFs. Treatments nowadays can prevent HFrEF progress, whereas only a few of the treatments have been proven to be effective in improving the survival of HFpEF. In this review, numerous mediators involved in the pathogenesis of HF are summarized. The regional upstream signaling and their diagnostic and therapeutic potential are also discussed. Additionally, the recent challenges and development in cardiac regenerative therapy that hold opportunities for future research and clinical translation are discussed.

Ionophore Ability of Carnosine and Its Trehalose Conjugate Assists Copper Signal in Triggering Brain-Derived Neurotrophic Factor and Vascular Endothelial Growth Factor Activation In Vitro

l-carnosine (β-alanyl-l-histidine) (Car hereafter) is a natural dipeptide widely distributed in mammalian tissues and reaching high concentrations (0.7-2.0 mM) in the brain. The molecular features of the dipeptide underlie the antioxidant, anti-aggregating and metal chelating ability showed in a large number of physiological effects, while the biological mechanisms involved in the protective role found against several diseases cannot be explained on the basis of the above-mentioned properties alone, requiring further research efforts. It has been reported that l-carnosine increases the secretion and expression of various neurotrophic factors and affects copper homeostasis in nervous cells inducing Cu cellular uptake in keeping with the key metal-sensing system. Having in mind this l-carnosine ability, here we report the copper-binding and ionophore ability of l-carnosine to activate tyrosine kinase cascade pathways in PC12 cells and stimulate the expression of BDNF. Furthermore, the study was extended to verify the ability of the dipeptide to favor copper signaling inducing the expression of VEGF. Being aware that the potential protective action of l-carnosine is drastically hampered by its hydrolysis, we also report on the behavior of a conjugate of l-carnosine with trehalose that blocks the carnosinase degradative activity. Overall, our findings describe a copper tuning effect on the ability of l-carnosine and, particularly its conjugate, to activate tyrosine kinase cascade pathways.

Angiogenin and Copper Crossing in Wound Healing

Angiogenesis plays a key role in the wound healing process, involving the migration, growth, and differentiation of endothelial cells. Angiogenesis is controlled by a strict balance of different factors, and among these, the angiogenin protein plays a relevant role. Angiogenin is a secreted protein member of the ribonuclease superfamily that is taken up by cells and translocated to the nucleus when the process of blood vessel formation has to be promoted. However, the chemical signaling that activates the protein, normally present in the plasma, and the transport pathways through which the protein enters the cell are still largely unclear. Copper is also an angiogenic factor that regulates angiogenin expression and participates in the activation of common signaling pathways. The interaction between angiogenin and copper could be a relevant mechanism in regulating the formation of new blood vessel pathways and paving the way to the development of new drugs for chronic non-healing wounds.

EHP-101 alleviates angiotensin II-induced fibrosis and inflammation in mice

Some cannabinoids showed anti-inflammatory and antifibrotic activities. EHP-101 is an oral lipidic formulation of the novel non-psychotropic cannabidiol aminoquinone VCE-004.8, which showed antifibrotic activity in murine models of systemic sclerosis induced by bleomycin. We herein examined the effect of EHP-101 on cardiac and other organ fibrosis in a mouse model induced by Angiotensin II. VCE-004.8 inhibited TGFβ- and Ang II-induced myofibroblast differentiation in cardiac fibroblasts detected by α-SMA expression. VCE-004.8 also inhibited Ang II-induced ERK 1 + 2 phosphorylation, NFAT activation and mRNA expression of IL1β, IL6, Col1A2 and CCL2 in cardiac fibroblasts. Mice infused with Ang II resulted in collagen accumulation in left ventricle, aortic, dermal, renal and pulmonary tissues; oral administration of EHP-101, Ajulemic acid and Losartan improved these phenotypes. In myocardial tissue, Ang II induced infiltration of T cells and macrophages together with the accumulation of collagen and Tenascin C; those were all reduced by either EHP-101 or Losartan treatment. Cardiac tissue RNA-Seq analyses revealed a similar transcriptomic signature for both treatments for inflammatory and fibrotic pathways. However, the gene set enrichment analysis comparing data from EHP-101 vs Losartan showed specific hallmarks modified only by EHP-101. Specifically, EHP-101 inhibited the expression of genes such as CDK1, TOP2A and MKi67 that are regulated to the E2 factor family of transcription factors. This study suggests that the oral administration of EHP-101 prevents and inhibits cardiac inflammation and fibrosis. Furthermore, EHP-101 inhibits renal, pulmonary and dermal fibrosis. EHP-101 could offer new opportunities in the treatment of cardiac fibrosis and other fibrotic diseases.

Copper Preserves Vasculature Structure and Function by Protecting Endothelial Cells from Apoptosis in Ischemic Myocardium

The present study was undertaken to investigate whether Cu protects vasculatures from ischemic injury in the heart. C57/B6 mice were introduced to myocardial ischemia (MI) by permanent ligation of the left anterior descending (LAD) coronary artery. Two hours post-LAD ligation, mice were intravenously injected with a Cu-albumin (Cu-alb) solution, or saline as control. At 1, 4, or 7 days post-MI, hearts were collected for further analysis. A dramatic decrease in CD31-positive endothelial cells concomitantly with abundant apoptosis, along with obstruction of blood flow, was observed in ischemic myocardium 1 day post-MI. The early Cu-alb treatment protected CD31-positive cells from apoptosis, along with a preservation of micro-vessels and a decrease in infarct size. This early vasculature preservation ensured myocardial blood perfusion and protected cardiac contractile function until 28 days post-MI. This strategy of Cu-alb treatment immediately following MI would help develop a therapeutic approach for acute heart attack patients in a clinical setting.

Copper nutrition and biochemistry and human (patho)physiology

The essential trace mineral copper plays important roles in human physiology and pathophysiology. Disruption of copper homeostasis may underlie the development of ischemic heart disease, and connective tissue and neurodegenerative disorders. Copper also likely participates in the host response to bacterial infection and is further implicated more broadly in regulating immunity. Recent studies further associate copper with disruption of lipid homeostasis, as is frequently seen in, for example, non-alcoholic fatty liver disease (NAFLD). Moreover, continuing investigation of copper chaperones has revealed new roles for these intracellular copper-binding proteins. Despite these (and many other) significant advances, many questions related to copper biology remain unanswered. For example, what are the most sensitive and specific biomarkers of copper status, and which ones are useful in marginal (or "sub-clinical" copper deficiency)? Further research on this topic is required to inform future investigations of copper metabolism in humans (so the copper status of study participants can be fully appreciated). Also, are current recommendations for copper intake adequate? Recent studies suggest that overt copper deficiency is more common than once thought, and further, some have suggested that the copper RDAs for adults may be too low. Additional human balance and interventional studies are necessary and could provide the impetus for reconsidering the copper RDAs in the future. These and myriad other unresolved aspects of copper nutrition will undoubtedly be the focus of future investigation.

Nutraceutical, Dietary, and Lifestyle Options for Prevention and Treatment of Ventricular Hypertrophy and Heart Failure

Although well documented drug therapies are available for the management of ventricular hypertrophy (VH) and heart failure (HF), most patients nonetheless experience a downhill course, and further therapeutic measures are needed. Nutraceutical, dietary, and lifestyle measures may have particular merit in this regard, as they are currently available, relatively safe and inexpensive, and can lend themselves to primary prevention as well. A consideration of the pathogenic mechanisms underlying the VH/HF syndrome suggests that measures which control oxidative and endoplasmic reticulum (ER) stress, that support effective nitric oxide and hydrogen sulfide bioactivity, that prevent a reduction in cardiomyocyte pH, and that boost the production of protective hormones, such as fibroblast growth factor 21 (FGF21), while suppressing fibroblast growth factor 23 (FGF23) and marinobufagenin, may have utility for preventing and controlling this syndrome. Agents considered in this essay include phycocyanobilin, N-acetylcysteine, lipoic acid, ferulic acid, zinc, selenium, ubiquinol, astaxanthin, melatonin, tauroursodeoxycholic acid, berberine, citrulline, high-dose folate, cocoa flavanols, hawthorn extract, dietary nitrate, high-dose biotin, soy isoflavones, taurine, carnitine, magnesium orotate, EPA-rich fish oil, glycine, and copper. The potential advantages of whole-food plant-based diets, moderation in salt intake, avoidance of phosphate additives, and regular exercise training and sauna sessions are also discussed. There should be considerable scope for the development of functional foods and supplements which make it more convenient and affordable for patients to consume complementary combinations of the agents discussed here. Research Strategy: Key word searching of PubMed was employed to locate the research papers whose findings are cited in this essay.

COMMD1 upregulation is involved in copper efflux from ischemic hearts

Copper depletion is associated with myocardial ischemic infarction, in which copper metabolism MURR domain 1 (COMMD1) is increased. The present study was undertaken to test the hypothesis that the elevated COMMD1 is responsible for copper loss from the ischemic myocardium, thus worsening myocardial ischemic injury. Mice (C57BL/6J) were subjected to left anterior descending coronary artery permanent ligation to induce myocardial ischemic infarction. In the ischemic myocardium, copper reduction was associated with a significant increase in the protein level of COMMD1. A tamoxifen-inducible, cardiomyocyte -specific Commd1 knockout mouse (C57BL/6J) model (COMMD1CMC▲/▲) was generated using the Cre-LoxP recombination system. COMMD1CMC▲/▲ and wild-type littermates were subjected to the same permanent ligation of left anterior descending coronary artery. At the 7th day after ischemic insult, COMMD1 deficiency suppressed copper loss in the heart, along with preservation of vascular endothelial growth factor and vascular endothelial growth factor receptor 1 expression and the integrity of the vascular system in the ischemic myocardium. Corresponding to this change, infarct size of ischemic heart was reduced and myocardial contractile function was well preserved in COMMD1CMC▲/▲ mice. These results thus demonstrate that upregulation of COMMD1 is at least partially responsible for copper efflux from the ischemic heart. Cardiomyocyte-specific deletion of COMMD1 helps preserve the availability of copper for angiogenesis, thus suppressing myocardial ischemic dysfunction.

Gold Nanoparticles Functionalized with Angiogenin for Wound Care Application

In this work, we aimed to develop a hybrid theranostic nano-formulation based on gold nanoparticles (AuNP)-having a known anti-angiogenic character-and the angiogenin (ANG), in order to tune the angiogenesis-related phases involved in the multifaceted process of the wound healing. To this purpose, spherical were surface "decorated" with three variants of the protein, namely, the recombinant (rANG), the wild-type, physiologically present in the human plasma (wtANG) and a new mutant with a cysteine substitution of the serine at the residue 28 (S28CANG). The hybrid biointerface between AuNP and ANG was scrutinized by a multi-technique approach based on dynamic light scattering, spectroscopic (UV-visible, circular dichroism) and microscopic (atomic force and laser scanning confocal) techniques. The analyses of optical features of plasmonic gold nanoparticles allowed for discrimination of different adsorption modes-i.e.; predominant physisorption and/or chemisorption-triggered by the ANG primary sequence. Biophysical experiments with supported lipid bilayers (SLB), an artificial model of cell membrane, were performed by means of quartz crystal microbalance with dissipation monitoring acoustic sensing technique. Cellular experiments on human umbilical vein endothelial cells (HUVEC), in the absence or presence of copper-another co-player of angiogenesis-were carried out to assay the nanotoxicity of the hybrid protein-gold nanoassemblies as well as their effect on cell migration and tubulogenesis. Results pointed to the promising potential of these nanoplatforms, especially the new hybrid Au-S28CANG obtained with the covalent grafting of the mutant on the gold surface, for the modulation of angiogenesis processes in wound care.

The Role of Fe, Zn, and Cu in Pregnancy

Iron (Fe), copper (Cu), and zinc (Zn) are microelements essential for the proper functioning of living organisms. These elements participatein many processes, including cellular metabolism and antioxidant and anti-inflammatory defenses, and also influence enzyme activity, regulate gene expression, and take part in protein synthesis. Fe, Cu, and Zn have a significant impact on the health of pregnant women and in the development of the fetus, as well as on the health of the newborn. A proper concentration of these elements in the body of women during pregnancy reduces the risk of complications such as anemia, induced hypertension, low birth weight, preeclampsia, and postnatal complications. The interactions between Fe, Cu, and Zn influence their availability due to their similar physicochemical properties. This most often occurs during intestinal absorption, where metal ions compete for binding sites with transport compounds. Additionally, the relationships between these ions have a great influence on the course of reactions in the tissues, as well as on their excretion, which can be stimulated or delayed. This review aims to summarize reports on the influence of Fe, Cu, and Zn on the course of single and multiple pregnancies, and to discuss the interdependencies and mechanisms occurring between Fe, Cu, and Zn.

Research on elastic recoil and restoration of vessel pulsatility of Zn-Cu biodegradable coronary stents

Coronary stents made of zinc (Zn)-0.8 copper (Cu) (in wt%) alloy were developed as biodegradable metal stents (Zn-Cu stents) in this study. The mechanical properties of the Zn-Cu stents and the possible gain effects were characterized by in vitro and in vivo experiments compared with 316L stainless steel stents (316L stents). Young's modulus of the as-extruded Zn-0.8Cu alloy and properties of the stents, including their intrinsic elastic recoil, stent trackability were evaluated compared with 316L stents. In vivo study was also conducted to evaluate restoration of pulsatility of vessel segment implanted stents. Both Zn-Cu stents and 316L stents have good acute lumen gain. By comparison, the advantages of Zn-Cu stents are as follows: (I) Zn-Cu stents have less intrinsic elastic recoil than 316L stents; (II) stent trackability indicates that Zn-Cu stents have a smaller push force when passing through curved blood vessels, which may cause less mechanical stimulation to blood vessels; (III) in vivo study suggests that Zn-Cu stents implantation better facilitates the recovery of vascular pulsatility.

The molecular mechanisms of copper metabolism and its roles in human diseases

Copper is an essential element in cells; it can act as either a recipient or a donor of electrons, participating in various reactions. However, an excess of copper ions in cells is detrimental as these copper ions can generate free radicals and increase oxidative stress. In multicellular organisms, copper metabolism involves uptake, distribution, sequestration, and excretion, at both the cellular and systemic levels. Mammalian enterocytes take in bioavailable copper ions from the diet in a Ctr1-dependent manner. After incorporation, cuprous ions are delivered to ATP7A, which pumps Cu⁺ from enterocytes into the blood. Copper ions arrive at the liver through the portal vein and are incorporated into hepatocytes by Ctr1. Then, Cu⁺ can be secreted into the bile or the blood via the Atox1/ATP7B/ceruloplasmin route. In the bloodstream, this micronutrient can reach peripheral tissues and is again incorporated by Ctr1. In peripheral tissue cells, cuprous ions are either sequestrated by molecules such as metallothioneins or targeted to utilization pathways by chaperons such as Atox1, Cox17, and CCS. Copper metabolism must be tightly controlled in order to achieve homeostasis and avoid disorders. A hereditary or acquired copper unbalance, including deficiency, overload, or misdistribution, may cause or aggravate certain diseases such as Menkes disease, Wilson disease, neurodegenerative diseases, anemia, metabolic syndrome, cardiovascular diseases, and cancer. A full understanding of copper metabolism and its roles in diseases underlies the identification of novel effective therapies for such diseases.

Molecular Insights Into Lysyl Oxidases in Cartilage Regeneration and Rejuvenation

Articular cartilage remains among the most difficult tissues to regenerate due to its poor self-repair capacity. The lysyl oxidase family (LOX; also termed as protein-lysine 6-oxidase), mainly consists of lysyl oxidase (LO) and lysyl oxidase-like 1-4 (LOXL1-LOXL4), has been traditionally defined as cuproenzymes that are essential for stabilization of extracellular matrix, particularly cross-linking of collagen and elastin. LOX is essential in the musculoskeletal system, particularly cartilage. LOXs-mediated collagen cross-links are essential for the functional integrity of articular cartilage. Appropriate modulation of the expression or activity of certain LOX members selectively may become potential promising strategy for cartilage repair. In the current review, we summarized the advances of LOX in cartilage homeostasis and functioning, as well as copper-mediated activation of LOX through hypoxia-responsive signaling axis during recent decades. Also, the molecular signaling network governing LOX expression has been summarized, indicating that appropriate modulation of hypoxia-responsive-signaling-directed LOX expression through manipulation of bioavailability of copper and oxygen is promising for further clinical implications of cartilage regeneration, which has emerged as a potential therapeutic approach for cartilage rejuvenation in tissue engineering and regenerative medicine. Therefore, targeted regulation of copper-mediated hypoxia-responsive signalling axis for selective modulation of LOX expression may become potential effective therapeutics for enhanced cartilage regeneration and rejuvenation in future clinical implications.

Copper promotion of myocardial regeneration

IMPACT STATEMENT

Copper promotes angiogenesis, but the mechanistic insights have not been fully elucidated until recently. In addition, the significance of copper promotion of angiogenesis in myocardial regeneration was increasingly revealed. Copper critically participates in the regulation of hypoxia-inducible factor 1 (HIF-1) of angiogenic gene expression. Interestingly, myocardial ischemia causes copper efflux from the heart, leading to suppression of angiogenesis, although HIF-1α, the critical subunit of HIF-1, remains accumulated in the ischemic myocardium. Strategies targeting copper specific delivery to the ischemic myocardium lead to selective activation of HIF-1-regulated angiogenic gene expression. Vascularization of the ischemic myocardium re-establishes the tissue injury microenvironment, and rebuilds the conduit for communication between the tissue injury signals and the remote regenerative responses including stem cells. This process promotes myocardial regeneration. Thus, a simple and effective copper supplementation to the ischemic myocardium would become a novel therapeutic approach to the treatment of patients with ischemic heart diseases.

Utilization of Cu-nanoparticles as medication agent to reduce atherosclerotic lesions of a bifurcated artery having compliant walls

OBJECTIVE

A theoretical analysis is presented to study the bio-nanofluid with copper as medication agent for atherosclerotic bifurcated artery with flexible walls.

DESIGN/APPROACH

The circulatory framework in human body is comprised of a system of veins that incorporate the bifurcation in this way the impact of copper nanoparticles on parent, at apex and on daughter artery regions (in the wake of being bifurcated) is watched. Streaming of blood along vessel segment is recognized to be newtonian. The consistent idea of the atherosclerotic arterial wall is additionally considered to make relationship with permeability aspects with arterial wall thickness. Copper nanoparticles are utilized to reduce the atherosclertic lesions for bifurcated stenotic artery.

FINDINGS

The designed equations along with the experimental values of copper nanoparticles and blood are utilized for theoretical investigation. Moreover, hemodynamics impacts are also figure out to examine the flow of blood for atherosclertic artery. Comparison between parent and daughter artery is plotted through velocity profile. To see the theoretical assistance of this copper mediated model in biomedical field, graphical illustration is presented. At the end, noticed that the inclusion of copper nanoparticles enhances the velocity significantly both for parent as well as daughter artery.

CONCLUSIONS

The circulation of blood is considered to be different from pressure between portions of atherosclerotic and non-atherosclerotic artery. Shear stress is reduces by changing the bifurcation angle for daughter artery while trend is reversed for parent artery. The size of inner circularting bolus decreases by changing compliant parameter for parent artery while shape is changed for daughter artery.

Angiogenic Endothelial Cell Signaling in Cardiac Hypertrophy and Heart Failure

Endothelial cells are, by number, one of the most abundant cell types in the heart and active players in cardiac physiology and pathology. Coronary angiogenesis plays a vital role in maintaining cardiac vascularization and perfusion during physiological and pathological hypertrophy. On the other hand, a reduction in cardiac capillary density with subsequent tissue hypoxia, cell death and interstitial fibrosis contributes to the development of contractile dysfunction and heart failure, as suggested by clinical as well as experimental evidence. Although the molecular causes underlying the inadequate (with respect to the increased oxygen and energy demands of the hypertrophied cardiomyocyte) cardiac vascularization developing during pathological hypertrophy are incompletely understood. Research efforts over the past years have discovered interesting mediators and potential candidates involved in this process. In this review article, we will focus on the vascular changes occurring during cardiac hypertrophy and the transition toward heart failure both in human disease and preclinical models. We will summarize recent findings in transgenic mice and experimental models of cardiac hypertrophy on factors expressed and released from cardiomyocytes, pericytes and inflammatory cells involved in the paracrine (dys)regulation of cardiac angiogenesis. Moreover, we will discuss major signaling events of critical angiogenic ligands in endothelial cells and their possible disturbance by hypoxia or oxidative stress. In this regard, we will particularly highlight findings on negative regulators of angiogenesis, including protein tyrosine phosphatase-1B and tumor suppressor p53, and how they link signaling involved in cell growth and metabolic control to cardiac angiogenesis. Besides endothelial cell death, phenotypic conversion and acquisition of myofibroblast-like characteristics may also contribute to the development of cardiac fibrosis, the structural correlate of cardiac dysfunction. Factors secreted by (dysfunctional) endothelial cells and their effects on cardiomyocytes including hypertrophy, contractility and fibrosis, close the vicious circle of reciprocal cell-cell interactions within the heart during pathological hypertrophy remodeling.

Profiling of nuclear copper-binding proteins under hypoxic condition

Under hypoxic condition, copper (Cu) accumulates in cell nuclei, and regulates the activity of hypoxia-inducible factor-1 (HIF-1) through Cu-binding proteins (CuBPs). To understand the CuBPs in the nucleus, proteomic approach was undertaken to explore the dynamic changes of the CuBPs in response to hypoxia. Human umbilical vein endothelial cells (HUVECs) were treated with dimethyloxalylglycine in a final concentration of 100 μM for 4 h to induce hypoxia, resulting in the accumulation of HIF-1α and Cu in the nucleus. Cu immobilized metal affinity chromatography was applied to extract the CuBPs, followed by identification using nanoliter-liquid chromatograpy combined with quadrupole time of flight tandem mass spectrometry (nanoLC-Q-TOF-MS/MS). There were 278 nuclear proteins that were found as CuBPs in the induced hypoxic group in contrast to 218 CuBPs in the control group. Functional annotation of these proteins in gene ontology category revealed that proteins participating in negative regulation of transcription from RNA polymerase II promoter were dramatically enriched by induced hypoixc treatment. Label-free quantitative proteomic approach identified quantitative changes of nuclear proteome; of 17 differentially expressed proteins, 8 were downregulated and 9 were upregulated in the induced hypoxic nuclei. Four of the 17 proteins were CuBPs, including ILF2 and TRA2B, both were downregulated, and LMNA and HSPB1, both were upregulated. We confirmed the protein change of ALB, LMNA and HSPB1 (HSP27) in real hypoxia, and suggested that the identified CuBPs could be the target for further study of Cu regulation of HIF-1 activity in the nucleus.

The Association Between Myocardial Fibrosis and Depressed Capillary Density in Rat Model of Left Ventricular Hypertrophy

Myocardial fibrogenesis is initiated once the coordination between oxygen supply and demand is disrupted in pressure overload-induced cardiac hypertrophy. Clinical observations showed that myocardial fibrosis did not evenly occur in the hypertrophic myocardium. The present study was undertaken to specifically address differential vulnerabilities to fibrogenesis of different regions in the myocardium subjected to pressure overload-induced hypertrophy. SD rats were divided into two groups, sham-operated control and ascending artery constriction-induced cardiac hypotrophy. Thirty-four weeks after surgery, rats were sacrificed and hearts were harvested. Myocardial tissues were processed and sequentially sectioned for detection of collagen deposition, myocyte hypertrophy and vascular density analysis. Redundant collagen stained with Sirius red and anti-collagen I antibody was found in the extracellular matrix, but high volume of collagen fraction was largely localized more in posterior and lateral walls than in anterior wall and interventricular septum, which is in accordance with the accumulation of fibroblasts. In association with the differential regional collagen accumulation, the cardiomyocytes were more hypertrophic in the posterior and lateral wall than the other left ventricle. However, the capillary density in the lateral and posterior walls was significantly decreased. The results indicated that the posterior and lateral walls were more vulnerable to fibrogenesis post-pressure overload-induced cardiac hypertrophy, which was associated with the depressed angiogenesis in these two regions.

The Involvement of Cytochrome c Oxidase in Mitochondrial Fusion in Primary Cultures of Neonatal Rat Cardiomyocytes

Cytochrome c oxidase (CCO) is a copper-dependent enzyme of mitochondrial respiratory chain. In pressure overload-induced cardiac hypertrophy, copper level and CCO activity are both depressed, along with disturbance in mitochondrial fusion and fission dynamics. Copper repletion leads to recovery of CCO activity and normalized mitochondrial dynamics. The present study was undertaken to define the link between CCO activity and mitochondrial dynamic changes. Primary cultures of neonatal rat cardiomyocytes were treated with phenylephrine to induce cell hypertrophy. Hypertrophic cardiomyocytes were then treated with copper to reverse hypertrophy. In the hypertrophic cardiomyocytes, CCO activity was depressed and mitochondrial fusion was suppressed. Upon copper repletion, CCO activity was recovered and mitochondrial fusion was reestablished. Depression of CCO activity by siRNA targeting CCO assembly homolog 17 (COX17), a copper chaperone for CCO, led to fragmentation of mitochondria, which was not recoverable by copper supplementation. This study thus demonstrates that copper-dependent CCO is critical for mitochondrial fusion in the regression of cardiomyocyte hypertrophy.

The loss of copper is associated with the increase in copper metabolism MURR domain 1 in ischemic hearts of mice

The distribution of copper (Cu) in the biological system is regulated by Cu transporters and chaperones. It has been known for a long time that myocardial ischemia is accompanied by the loss of Cu from the heart, but the mechanism by which this occurs remains unknown. The present study was undertaken to understand the relationship between Cu loss and alterations in Cu transporters during the pathogenesis of myocardial ischemia. Male mice (C57 BL/6J) were subjected to left anterior descending (LAD) coronary artery ligation to induce myocardial ischemia. Changes in Cu concentrations in serum and hearts were determined from blood and tissue samples harvested at different time points for a total of 28 days after the operation. Cu concentrations in the ischemic myocardium were continuously decreased starting at the fourth day after LAD artery ligation, gradually depleted by more than 80% of the normal level at the 10th day, and remained at the lowest level (about 20% of normal levels) thereafter. Serum Cu concentrations were correspondingly increased starting at the fourth day, reached to the highest level between day 7 and 10, and gradually recovered to the normal level until 21st day after the operation. Along with the same time course, the intracellular Cu exporter copper metabolism MURR domain 1 (COMMD1) was significantly and sustainably increased, but ATP7A and ATP7B were not significantly changed in the ischemic myocardium. These results suggest that during the pathogenesis of myocardial ischemia, COMMD1 would play a critical role in exporting Cu from the ischemic myocardium to the blood. Impact statement In this work, we found that copper efflux from the ischemic heart leads to the elevation of serum copper concentrations, addressing a long-term question related to serum copper elevation in myocardial ischemia patients. The efflux of copper from the ischemic heart results at least in part from the upregulation of copper metabolism MURR domain 1 (COMMD1) in the heart upon ischemic insult. This work provides a novel insight into copper homeostasis and alteration in cardiovascular system.

Copper affects the binding of HIF-1α to the critical motifs of its target genes

Copper regulates the target gene selection of HIF-1α under hypoxic conditions by affecting HIF-1α-DNA binding patterns across the genome.

Trientine selectively delivers copper to the heart and suppresses pressure overload-induced cardiac hypertrophy in rats

Dietary copper supplementation reverses pressure overload-induced cardiac hypertrophy by copper replenishment in the heart. A copper-selective chelator, trientine (triethylenetetramine [TETA]), reverses left ventricular hypertrophy associated with diabetes also by copper replenishment in the heart. The present study was undertaken to address the critical issue how TETA delivers copper to the heart. Adult male Sprague-Dawley rats were subjected to transverse aortic constriction (TAC) to induce cardiac hypertrophy. Eight weeks after the TAC surgery, cardiac hypertrophy was developed and copper content in the heart was reduced. TETA was then administrated by gavage in two different dosages (21.9 or 87.6 mg/kg day) for six weeks. The results showed that in the lower dosage, TETA replenished copper contents in the heart, along with a decrease in the copper concentration in the blood and kidney, and an increase in the urine. In the higher dosage, TETA did not replenish copper contents in the heart, but markedly increased copper concentrations in the urine and decreased those in the blood and kidney. Neither lower nor higher TETA dosage altered copper concentrations in other organs. Corresponding to myocardial copper replenishment, the lower dose TETA suppresses cardiac hypertrophy, as judged by a reduction in the left ventricle wall thickness and a decrease in the heart size, and diminished cardiac fibrosis, as reflected by a decrease in collagen I content. TETA in the higher dose not only did not suppress cardiac hypertrophy, but also caused cardiac hypertrophy in sham-operated rats. TETA-mediated myocardial copper restoration is independent of copper transporter-1 or -2 but related to an energy-dependent transportation. This study demonstrates that low-dose TETA functions as a copper chaperone, selectively delivering copper to the copper-deprived heart through an active transportation; in higher doses, TETA simply retains its chelator function, removing copper from the body by urinary excretion.

Impact statement

Our study reveals that TETA, traditionally regarded as a copper chelator, in lower doses delivers copper selectively to the heart through a mechanism independent of copper transporter-1 or -2. Copper supplementation by a lower dose of TETA suppresses pressure overload-induced cardiac hypertrophy. Since ischemic heart disease and hypertrophic cardiomyopathy are accompanied by myocardial copper loss, this approach of using a lower dose of TETA to supplement copper to the heart would help treat the disease condition of patients with such cardiac events.

Copper transporters and copper chaperones: roles in cardiovascular physiology and disease

Copper (Cu) is an essential micronutrient but excess Cu is potentially toxic. Its important propensity to cycle between two oxidation states accounts for its frequent presence as a cofactor in many physiological processes through Cu-containing enzymes, including mitochondrial energy production (via cytochrome c-oxidase), protection against oxidative stress (via superoxide dismutase), and extracellular matrix stability (via lysyl oxidase). Since free Cu is potentially toxic, the bioavailability of intracellular Cu is tightly controlled by Cu transporters and Cu chaperones. Recent evidence reveals that these Cu transport systems play an essential role in the physiological responses of cardiovascular cells, including cell growth, migration, angiogenesis and wound repair. In response to growth factors, cytokines, and hypoxia, their expression, subcellular localization, and function are tightly regulated. Cu transport systems and their regulators have also been linked to various cardiovascular pathophysiologies such as hypertension, inflammation, atherosclerosis, diabetes, cardiac hypertrophy, and cardiomyopathy. A greater appreciation of the central importance of Cu transporters and Cu chaperones in cell signaling and gene expression in cardiovascular biology offers the possibility of identifying new therapeutic targets for cardiovascular disease.

Copper supplementation reverses dietary iron overload-induced pathologies in mice

Dietary iron overload in rodents impairs growth and causes cardiac hypertrophy, serum and tissue copper depletion, depression of serum ceruloplasmin (Cp) activity and anemia. Notably, increasing dietary copper content to ~25-fold above requirements prevents the development of these physiological perturbations. Whether copper supplementation can reverse these high-iron-related abnormalities has, however, not been established. The current investigation was thus undertaken to test the hypothesis that supplemental copper will mitigate negative outcomes associated with dietary iron loading. Weanling mice were thus fed AIN-93G-based diets with high (>100-fold in excess) or adequate (~80 ppm) iron content. To establish the optimal experimental conditions, we first defined the time course of iron loading, and assessed the impact of supplemental copper (provided in drinking water) on the development of high-iron-related pathologies. Copper supplementation (20 mg/L) for the last 3 weeks of a 7-week high-iron feeding period reversed the anemia, normalized serum copper levels and Cp activity, and restored tissue copper concentrations. Growth rates, cardiac copper concentrations and heart size, however, were only partially normalized by copper supplementation. Furthermore, high dietary iron intake reduced intestinal ⁶⁴Cu absorption (~60%) from a transport solution provided to mice by oral, intragastric gavage. Copper supplementation of iron-loaded mice enhanced intestinal ⁶⁴Cu transport, thus allowing sufficient assimilation of dietary copper to correct many of the noted high-iron-related physiological perturbations. We therefore conclude that high- iron intake increases the requirement for dietary copper (to overcome the inhibition of intestinal copper absorption).

Copper-induced reduction in myocardial fibrosis is associated with increased matrix metalloproteins in a rat model of cardiac hypertrophy

AAC induces Cu loss from the heart and depressed MMP-2 in combination with increased TIMPs, leading to increased collagen deposition. TETA replenishes Cu in the heart, increases MMP-2, and decreases TIMP-1 and -2, collectively resulting in reduction in cardiac fibrosis.

The association of depressed angiogenic factors with reduced capillary density in the Rhesus monkey model of myocardial ischemia

Depressed capillary density is associated with myocardial ischemic infarction, in which hypoxia-inducible factor 1α (HIF-1α) is increased. The present study was undertaken to examine changes in the angiogenic factors whose expression is regulated by HIF-1 and their relation to the depressed capillary density in the Rhesus monkey model of myocardial ischemic infarction. Male Rhesus monkeys 2-3 years old were subjected to myocardial ischemia by permanent ligation of left anterior descending (LAD) artery leading to the development of myocardial infarction. Eight weeks after LAD ligation, copper concentrations, myocardial histological changes and capillary density were examined, along with Western blot and immunohistochemical analysis of angiogenic factors and detection of HIF-1 activity. Capillary density was significantly decreased but the concentrations of HIF-1α and HIF-1β were significantly increased in the infarct area. However, the levels of mRNA and protein for VEGF and VEGFR1 were significantly decreased. Other HIF-1 regulated angiogenic factors, including Tie-2, Ang-1 and FGF-1, were also significantly depressed, but vascular destabilizing factor Ang-2 was significantly increased. Copper concentrations were depressed in the infarct area. Copper-independent HIF-1 activity was increased shown by the elevated mRNA level of IGF-2, a HIF-1 target gene. Removal of copper by a copper chelator, tetraethylenepentamine, from primary cultures of neonatal rat cardiomyocytes also suppressed the expression of HIF-1 regulated VEGF and BNIP3, but not IGF-2. The data suggest that under ischemic conditions, copper loss suppressed the expression of critical angiogenic genes regulated by HIF-1, but did not affect copper-independent HIF-1 activation of gene expression. This copper-dependent dysregulation of angiogenic gene expression would contribute to the pathogenesis of myocardial ischemic infarction.

VEGFB-VEGFR1 ameliorates Ang II-induced cardiomyocyte hypertrophy through Ca2+ -mediated PKG I pathway

In response to assorted stimuli, the heart will develop into cardiomyocyte hypertrophy, but sustained cardiomyocyte hypertrophy will finally lead to heart failure. This research is aimed to examine the effect of VEGFB on cardiomyocyte hypertrophy by using the cardiomyocyte-derived cell line H9C2 of cultured rates. It turns out that VEGFB can positively prevent the Ang II-induced rising in the size of cardiomyocyte as well as reduce Ang II-induced mRNA and protein levels of β-MHC (β-myosin heavy chain), BNP (brain natriuretic peptide), and ANP (atrial natriuretic peptide). Moreover, VEGFB can regulate the decline of the Ang II-induced rising in Ca²⁺ . After VEGFR1 knockdown, these effects of VEGFB were partially reversed. Moreover, VEGFB attenuated the suppression of PKG I, p-VASP, and RGS2 caused by Ang II; whereas VEGFR1 knockdown partially abolished the indicated effect of VEGFB. In a word, the effect of VEGFB on relevant downstream targets and the pathways of PKG I by VEGFR1 may explain its efficacy on cardiomyocyte hypertrophy. Thus, it can be suggested that it is feasible to apply VEGFB-VEGFR1 for reducing the symptoms of cardiomyocyte hypertrophy.