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Antibacterial Titanium Implants Biofunctionalized by Plasma Electrolytic Oxidation with Silver, Zinc, and Copper: A Systematic Review.
van Hengel, IAJ, Tierolf, MWAM, Fratila-Apachitei, LE, Apachitei, I, Zadpoor, AA
International journal of molecular sciences. 2021;(7)
Abstract
Patients receiving orthopedic implants are at risk of implant-associated infections (IAI). A growing number of antibiotic-resistant bacteria threaten to hamper the treatment of IAI. The focus has, therefore, shifted towards the development of implants with intrinsic antibacterial activity to prevent the occurrence of infection. The use of Ag, Cu, and Zn has gained momentum as these elements display strong antibacterial behavior and target a wide spectrum of bacteria. In order to incorporate these elements into the surface of titanium-based bone implants, plasma electrolytic oxidation (PEO) has been widely investigated as a single-step process that can biofunctionalize these (highly porous) implant surfaces. Here, we present a systematic review of the studies published between 2009 until 2020 on the biomaterial properties, antibacterial behavior, and biocompatibility of titanium implants biofunctionalized by PEO using Ag, Cu, and Zn. We observed that 100% of surfaces bearing Ag (Ag-surfaces), 93% of surfaces bearing Cu (Cu-surfaces), 73% of surfaces bearing Zn (Zn-surfaces), and 100% of surfaces combining Ag, Cu, and Zn resulted in a significant (i.e., >50%) reduction of bacterial load, while 13% of Ag-surfaces, 10% of Cu-surfaces, and none of Zn or combined Ag, Cu, and Zn surfaces reported cytotoxicity against osteoblasts, stem cells, and immune cells. A majority of the studies investigated the antibacterial activity against S. aureus. Important areas for future research include the biofunctionalization of additively manufactured porous implants and surfaces combining Ag, Cu, and Zn. Furthermore, the antibacterial activity of such implants should be determined in assays focused on prevention, rather than the treatment of IAIs. These implants should be tested using appropriate in vivo bone infection models capable of assessing whether titanium implants biofunctionalized by PEO with Ag, Cu, and Zn can contribute to protect patients against IAI.
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Relation of Serum Copper Status to Survival in COVID-19.
Hackler, J, Heller, RA, Sun, Q, Schwarzer, M, Diegmann, J, Bachmann, M, Moghaddam, A, Schomburg, L
Nutrients. 2021;(6)
Abstract
The trace element copper (Cu) is part of our nutrition and essentially needed for several cuproenzymes that control redox status and support the immune system. In blood, the ferroxidase ceruloplasmin (CP) accounts for the majority of circulating Cu and serves as transport protein. Both Cu and CP behave as positive, whereas serum selenium (Se) and its transporter selenoprotein P (SELENOP) behave as negative acute phase reactants. In view that coronavirus disease (COVID-19) causes systemic inflammation, we hypothesized that biomarkers of Cu and Se status are regulated inversely, in relation to disease severity and mortality risk. Serum samples from COVID-19 patients were analysed for Cu by total reflection X-ray fluorescence and CP was quantified by a validated sandwich ELISA. The two Cu biomarkers correlated positively in serum from patients with COVID-19 (R = 0.42, p < 0.001). Surviving patients showed higher mean serum Cu and CP concentrations in comparison to non-survivors ([mean+/-SEM], Cu; 1475.9+/-22.7 vs. 1317.9+/-43.9 µg/L; p < 0.001, CP; 547.2.5 +/- 19.5 vs. 438.8+/-32.9 mg/L, p = 0.086). In contrast to expectations, total serum Cu and Se concentrations displayed a positive linear correlation in the patient samples analysed (R = 0.23, p = 0.003). Serum CP and SELENOP levels were not interrelated. Applying receiver operating characteristics (ROC) curve analysis, the combination of Cu and SELENOP with age outperformed other combinations of parameters for predicting risk of death, yielding an AUC of 95.0%. We conclude that the alterations in serum biomarkers of Cu and Se status in COVID-19 are not compatible with a simple acute phase response, and that serum Cu and SELENOP levels contribute to a good prediction of survival. Adjuvant supplementation in patients with diagnostically proven deficits in Cu or Se may positively influence disease course, as both increase in survivors and are of crucial importance for the immune response and antioxidative defence systems.
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Potential molecular mechanisms of zinc- and copper-mediated antiviral activity on COVID-19.
Rani, I, Goyal, A, Bhatnagar, M, Manhas, S, Goel, P, Pal, A, Prasad, R
Nutrition research (New York, N.Y.). 2021;:109-128
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Abstract
Novel coronavirus disease 2019 (COVID-19) has spread across the globe; and surprisingly, no potentially protective or therapeutic antiviral molecules are available to treat severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. However, zinc (Zn) and copper (Cu) have been shown to exert protective effects due to their antioxidant, anti-inflammatory, and antiviral properties. Therefore, it is hypothesized that supplementation with Zn and Cu alone or as an adjuvant may be beneficial with promising efficacy and a favorable safety profile to mitigate symptoms, as well as halt progression of the severe form of SARS-CoV-2 infection. The objective of this review is to discuss the proposed underlying molecular mechanisms and their implications for combating SARS-CoV-2 infection in response to Zn and Cu administration. Several clinical trials have also included the use of Zn as an adjuvant therapy with dietary regimens/antiviral drugs against COVID-19 infection. Overall, this review summarizes that nutritional intervention with Zn and Cu may offer an alternative treatment strategy by eliciting their virucidal effects through several fundamental molecular cascades, such as, modulation of immune responses, redox signaling, autophagy, and obstruction of viral entry and genome replication during SARS-CoV-2 infection.
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The Role of Copper Homeostasis at the Host-Pathogen Axis: From Bacteria to Fungi.
Li, C, Li, Y, Ding, C
International journal of molecular sciences. 2019;(1)
Abstract
Copper is an essential trace element participating in many vital biological processes, however it becomes a toxic agent when in excess. Thus, precise and tight regulation of copper homeostasis processes, including transport, delivery, storage, detoxification, and efflux machineries, is important, ensuring that only the amount needed to sustain basic biological functions and simultaneously prevent copper toxicity in the cell is maintained. Numerous exciting studies have revealed that copper plays an indispensable role at the microbial pathogen-host axis for entities ranging from pathogenic bacteria to deadly fungal species. Analyses of copper homeostases in bacteria and fungi extensively demonstrate that copper is utilized by the host immune system as an anti-microbial agent. The expression of copper efflux and detoxification from microbial pathogens is induced to counteract the host's copper bombardment, which in turn disrupts these machineries, resulting in the attenuation of microbial survival in host tissue. We hereby review the latest work in copper homeostases in pathogenic bacteria and fungi and focus on the maintenance of a copper balance at the pathogen-host interaction axis.
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Dietary copper and human health: Current evidence and unresolved issues.
Bost, M, Houdart, S, Oberli, M, Kalonji, E, Huneau, JF, Margaritis, I
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 2016;:107-15
Abstract
Although copper (Cu) is recognized as an essential trace element, uncertainties remain regarding Cu reference values for humans, as illustrated by discrepancies between recommendations issued by different national authorities. This review examines human studies published since 1990 on relationships between Cu intake, Cu balance, biomarkers of Cu status, and health. It points out several gaps and unresolved issues which make it difficult to assess Cu requirements. Results from balance studies suggest that daily intakes below 0.8 mg/day lead to net Cu losses, while net gains are consistently observed above 2.4 mg/day. However, because of an incomplete collection of losses in all studies, a precise estimation of Cu requirements cannot be derived from available data. Data regarding the relationship between Cu intake and potential biomarkers are either too preliminary or inconclusive because of low specificity or low sensitivity to change in dietary Cu over a wide range of intakes. Results from observation and intervention studies do not support a link between Cu and a risk of cardiovascular disease, cognitive decline, arthritis or cancer for intakes ranging from 0.6 to 3mg/day, and limited evidence exists for impaired immune function in healthy subjects with a very low (0.38 mg/day) Cu intake. However, data from observation studies should be regarded with caution because of uncertainties regarding Cu concentration in various foods and water. Further studies that accurately evaluate Cu exposure based on reliable biomarkers of Cu status are needed.
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Effects of zinc supplementation on plasma copper/zinc ratios, oxidative stress, and immunological status in hemodialysis patients.
Guo, CH, Wang, CL
International journal of medical sciences. 2013;(1):79-89
Abstract
BACKGROUND Patients undergoing hemodialysis (HD) have low plasma levels of zinc (Zn), high plasma levels of copper (Cu), and exhibit increased oxidative stress, inflammation, and immune abnormalities. We evaluated the effects of Zn supplementation on abnormal plasma Cu/Zn ratios and clinical outcomes in HD patients. DESIGN AND METHODS Patients on long-term HD with lower than normal plasma concentrations of Zn (< 80 mg/dL) were randomized to receive daily oral Zn supplements (n = 40) or no supplements (n = 25) for eight weeks. Age- and sex-matched healthy individuals served as a control group (n = 38). A number of clinical parameters were measured before and after the supplementation period. RESULTS Compared with healthy subjects, patients had significantly elevated plasma Cu concentrations and Cu/Zn ratios, as well as higher levels of oxidative stress and pro-inflammatory cytokines. Patients who received Zn supplements for eight weeks had higher plasma concentrations of Zn and lower concentrations of Cu, along with reduced Cu/Zn ratios, oxidative stress status, and inflammatory responses compared to patients who did not receive Zn. Patients receiving Zn also showed significantly higher percentages of CD4 and CD19 lymphocytes, and elevated CD4/CD8 ratios. CONCLUSIONS Zn supplementation ameliorates abnormally high plasma Cu/Zn ratios and may reduce oxidative stress, improve inflammatory status, and maintain immune function in patients undergoing long-term HD.
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Human copper transporters: mechanism, role in human diseases and therapeutic potential.
Gupta, A, Lutsenko, S
Future medicinal chemistry. 2009;(6):1125-42
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Abstract
Normal copper homeostasis is essential for human growth and development. Copper deficiency, caused by genetic mutations, inadequate diet or surgical interventions, may lead to cardiac hypertrophy, poor neuronal myelination, blood vessel abnormalities and impaired immune response. Copper overload is associated with morphological and metabolic changes in tissues and, if untreated, eventual death. Recent reports also indicate that changes in the expression of copper transporters alter the sensitivity of cancer cells to major chemotherapeutic drugs, such as cisplatin, although the mechanism behind this important phenomenon remains unclear. This review summarizes current information on the molecular characteristics of copper transporters CTR1, CTR2, ATP7A and ATP7B, their roles in mammalian copper homeostasis and the physiological consequences of their inactivation. The mechanisms through which copper transporters may influence cell sensitivity to cisplatin are discussed. Regulation of human copper homeostasis has significant therapeutic potential and requires the detailed understanding of copper transport mechanisms.
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Circulating immune complexes and trace elements (Copper, Iron and Selenium) as markers in oral precancer and cancer : a randomised, controlled clinical trial.
Khanna, SS, Karjodkar, FR
Head & face medicine. 2006;:33
Abstract
AIM: To evaluate the levels of circulating immune complexes, trace elements (copper, iron and selenium) in serum of patients with oral submucous fibrosis (OSMF), oral leukoplakia (L), and oral squamous cell carcinoma (SCC), analyze the alteration and identify the best predictors amongst these parameters for disease occurrence and progression. METHODS Circulating immune complexes (CIC) were estimated using 37.5% Polyethylene Glycol 6000(PEG) serum precipitation. Serum estimation of copper (Cu), Iron (Fe) and selenium (Se) was done using the Oxalyl Dihydrazide method, Colorimetric Dipyridyl method and the Differential Pulse Cathodic Stripping Voltametry respectively. RESULTS The data analysis revealed increased circulating immune complex levels in the precancer and cancer patients. Serum copper levels showed gradual increase from precancer to cancer patients. However, serum iron levels were decreased significantly in the cancer group. Selenium levels showed marked decrease in the cancer group. Among CIC, serum, copper, iron and selenium the best predictors for the occurrence of lesions were age, serum iron, CIC, serum selenium in the decreasing order. CONCLUSION The present study shows that these immunological and biological markers may be associated with the pathogenesis of oral premalignant and malignant lesions and their progressions. Concerted efforts would, therefore, help in early detection, management, and monitoring the efficacy of treatment.