The Role of Copper in Human Diet and Risk of Dementia

Deadly excess copper

Higher eukaryotes' life is impossible without copper redox activity and, literally, every breath we take biochemically demonstrates this. However, this dependence comes at a considerable price to ensure target-oriented copper action. Thereto its uptake, distribution but also excretion are executed by specialized proteins with high affinity for the transition metal. Consequently, malfunction of copper enzymes/transporters, as is the case in hereditary Wilson disease that affects the intracellular copper transporter ATP7B, comes with serious cellular damage. One hallmark of this disease is the progressive copper accumulation, primarily in liver but also brain that becomes deadly if left untreated. Such excess copper toxicity may also result from accidental ingestion or attempted suicide. Recent research has shed new light into the cell-toxic mechanisms and primarily affected intracellular targets and processes of such excess copper that may even be exploited with respect to cancer therapy. Moreover, new therapies are currently under development to fight against deadly toxic copper.

Sulfur-bridging the gap: investigating the electrochemistry of novel copper chelating agents for Alzheimer's disease applications

There is currently an unmet demand for multi-functional precision treatments for Alzheimer's disease (AD) after several failed attempts at designing drugs based on the amyloid hypothesis. The focus of this work is to investigate sulfur-bridged quinoline ligands that could potentially be used in chelation therapies for a subpopulation of AD patients presenting with an overload of labile copper ions, which are known to catalyze the production of reactive oxygen species (ROS) and exacerbate other markers of AD progression. The ligands 1-(2'-thiopyridyl)isoquinoline (1TPIQ) and 2-(2'-thiopyridyl)quinoline (2TPQ) were synthesized and characterized before being electrochemically investigated in the presence of different oxidizing and reducing agents in solution with a physiological pH relevant to the brain. The electrochemical response of each compound with copper was studied by employing both hydrogen peroxide (H2O2) as an oxidizing agent and ascorbic acid (AA) as an antioxidant during analysis using cyclic voltammetry (CV). The cyclic voltammograms of each quinoline were compared with similar ligands that contained aromatic N-donor groups but no sulfur groups to provide relative electrochemical properties of each complex in solution. In a dose-dependent manner, it was observed that AA exerted dual-efficacy when combined with these chelating ligands: promoting synergistic metal binding while also scavenging harmful ROS, suggesting AA is an effective adjuvant therapeutic agent. Overall, this study shows how coordination by sulfur-bridged quinoline ligands can alter copper electrochemistry in the presence of AA to limit ROS production in solution.

Bio-high entropy alloys: Progress, challenges, and opportunities

With the continuous progress and development in biomedicine, metallic biomedical materials have attracted significant attention from researchers. Due to the low compatibility of traditional metal implant materials with the human body, it is urgent to develop new biomaterials with excellent mechanical properties and appropriate biocompatibility to solve the adverse reactions caused by long-term implantation. High entropy alloys (HEAs) are nearly equimolar alloys of five or more elements, with huge compositional design space and excellent mechanical properties. In contrast, biological high-entropy alloys (Bio-HEAs) are expected to be a new bio-alloy for biomedicine due to their excellent biocompatibility and tunable mechanical properties. This review summarizes the composition system of Bio-HEAs in recent years, introduces their biocompatibility and mechanical properties of human bone adaptation, and finally puts forward the following suggestions for the development direction of Bio-HEAs: to improve the theory and simulation studies of Bio-HEAs composition design, to quantify the influence of composition, process, post-treatment on the performance of Bio-HEAs, to focus on the loss of Bio-HEAs under actual service conditions, and it is hoped that the clinical application of the new medical alloy Bio-HEAs can be realized as soon as possible.

Antibacterial metals and alloys for potential biomedical implants

Metals and alloys, including stainless steel, titanium and its alloys, cobalt alloys, and other metals and alloys have been widely used clinically as implant materials, but implant-related infection or inflammation is still one of the main causes of implantation failure. The bacterial infection or inflammation that seriously threatens human health has already become a worldwide complaint. Antibacterial metals and alloys recently have attracted wide attention for their long-term stable antibacterial ability, good mechanical properties and good biocompatibility in vitro and in vivo. In this review, common antibacterial alloying elements, antibacterial standards and testing methods were introduced. Recent developments in the design and manufacturing of antibacterial metal alloys containing various antibacterial agents were described in detail, including antibacterial stainless steel, antibacterial titanium alloy, antibacterial zinc and alloy, antibacterial magnesium and alloy, antibacterial cobalt alloy, and other antibacterial metals and alloys. Researches on the antibacterial properties, mechanical properties, corrosion resistance and biocompatibility of antibacterial metals and alloys have been summarized in detail for the first time. It is hoped that this review could help researchers understand the development of antibacterial alloys in a timely manner, thereby could promote the development of antibacterial metal alloys and the clinical application.

Agricultural Use of Copper and Its Link to Alzheimer's Disease

Copper is an essential nutrient for plants, animals, and humans because it is an indispensable component of several essential proteins and either lack or excess are harmful to human health. Recent studies revealed that the breakdown of the regulation of copper homeostasis could be associated with Alzheimer's disease (AD), the most common form of dementia. Copper accumulation occurs in human aging and is thought to increase the risk of AD for individuals with a susceptibility to copper exposure. This review reports that one of the leading causes of copper accumulation in the environment and the human food chain is its use in agriculture as a plant protection product against numerous diseases, especially in organic production. In the past two decades, some countries and the EU have invested in research to reduce the reliance on copper. However, no single alternative able to replace copper has been identified. We suggest that agroecological approaches are urgently needed to design crop protection strategies based on the complementary actions of the wide variety of crop protection tools for disease control.

Association Between Serum Ceruloplasmin Specific Activity and Risk of Alzheimer's Disease

Meta-analyses demonstrate copper involvement in Alzheimer's disease (AD), and the systemic ceruloplasmin status in relation to copper is an emerging issue. To deepen this matter, we evaluated levels of ceruloplasmin concentration, ceruloplasmin activity, ceruloplasmin specific activity (eCp/iCp), copper, non-ceruloplasmin copper iron, transferrin, the ceruloplasmin/transferrin ratio, and the APOE genotype in a sample of 84 AD patients and 58 healthy volunteers. From the univariate logistic analyses we found that ceruloplasmin concentration, eCp/iCp, copper, transferrin, the ceruloplasmin/transferrin ratio, and the APOE genotype were significantly associated with the probability of AD. In the multivariable logistic regression analysis, we selected the best subset of biological predictors by the forward stepwise procedure. The analysis showed a decrease of the risk of having AD for eCp/iCp (p = 0.001) and an increase of this risk for non-ceruloplasmin copper (p = 0.008), age (p = 0.001), and APOE-ɛ4 allele (p <  0.001). The estimated model showed a good power in discriminating AD patients from healthy controls (area under curve: 88% ; sensitivity: 66% ; specificity 93%). These data strength the breakdown of copper homeostasis and propose eCp/iCp as a reliable marker of ceruloplasmin status.