Copper and zinc status during acute inflammation: studies on blood, liver and kidneys metal levels in normal and inflamed rats

The Relationship Between Metabolic Syndrome Development and Tissue Trace Elements Status and Inflammatory Markers

Insulin resistance, impaired glucose regulation, dyslipidemia, low-grade inflammation, and elevated blood pressure are main components of the metabolic syndrome (MetS). Trace elements, especially zinc (Zn) and copper (Cu) and cytokines, have physiological importance due to their presence in inflammatory processes and glucose metabolism. Therefore, this study aimed to investigate the potential relationship between cytokine responses and trace elements in different tissues of sucrose-induced MetS rats compared with healthy controls (n:7/groups). Tissue Zn concentrations are found to be decreased in the liver (p = 0.00) and pancreas (p < 0.01) and increased in the kidney (p = 0.00) and heart tissues (p < 0.001) of MetS group. Serum Zn levels were also found to be decreased in MetS compared with control group (p < 0.01), while there was any significant difference in serum Cu concentrations between groups. The Cu concentration (p < 0.01) was found decreased, and Zn/Cu ratio (p < 0.01) was found increased in kidney tissues. TNF-α, IL-6 levels were found increased in MetS tissues. With this study, the Zn and Cu concentrations and their relationships with inflammatory response in different tissues in MetS are reported for the first time in the literature. Serum and tissue Zn levels with diversities in distribution were found to have a higher impact on MetS pathogenesis than Cu levels. It has been concluded that there is a relationship between Zn and Cu concentrations and inflammatory marker levels in MetS pathophysiological mechanisms.

Pre-diagnostic copper and zinc biomarkers and colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition cohort

Adequate intake of copper and zinc, two essential micronutrients, are important for antioxidant functions. Their imbalance may have implications for development of diseases like colorectal cancer (CRC), where oxidative stress is thought to be etiologically involved. As evidence from prospective epidemiologic studies is lacking, we conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to investigate the association between circulating levels of copper and zinc, and their calculated ratio, with risk of CRC development. Copper and zinc levels were measured by reflection X-ray fluorescence spectrometer in 966 cases and 966 matched controls. Multivariable adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression and are presented for the fifth versus first quintile. Higher circulating concentration of copper was associated with a raised CRC risk (OR = 1.50; 95% CI: 1.06, 2.13; P-trend = 0.02) whereas an inverse association with cancer risk was observed for higher zinc levels (OR = 0.65; 95% CI: 0.43, 0.97; P-trend = 0.07). Consequently, the ratio of copper/zinc was positively associated with CRC (OR = 1.70; 95% CI: 1.20, 2.40; P-trend = 0.0005). In subgroup analyses by follow-up time, the associations remained statistically significant only in those diagnosed within 2 years of blood collection. In conclusion, these data suggest that copper or copper levels in relation to zinc (copper to zinc ratio) become imbalanced in the process of CRC development. Mechanistic studies into the underlying mechanisms of regulation and action are required to further examine a possible role for higher copper and copper/zinc ratio levels in CRC development and progression.

Iron, hepcidin, and the metal connection

Identification of new players in iron metabolism, such as hepcidin, which regulates ferroportin and divalent metal transporter 1 expression, has improved our knowledge of iron metabolism and iron-related diseases. However, from both experimental data and clinical findings, "iron-related proteins" appear to also be involved in the metabolism of other metals, especially divalent cations. Reports have demonstrated that some metals may affect, directly or indirectly, the expression of proteins involved in iron metabolism. Throughout their lives, individuals are exposed to various metals during personal and/or occupational activities. Therefore, better knowledge of the connections between iron and other metals could improve our understanding of iron-related diseases, especially the variability in phenotypic expression, as well as a variety of diseases in which iron metabolism is secondarily affected. Controlling the metabolism of other metals could represent a promising innovative therapeutic approach.

Zinc and skin health: overview of physiology and pharmacology

BACKGROUND

Zinc is known to have a critical role in overall human physiology, which likely explains many of its therapeutic uses for the last several thousand years. The specific roles zinc plays in skin health and function are less widely known yet are likely just as critical based on the manifestations of dietary zinc deprivation, which include moderate to severe dermatitis.

OBJECTIVE

To provide a critical review of the scientific literature as to the physiologic importance of zinc to skin, the biochemical basis for these effects, and pharmacologic aspects of zinc therapeutics.

RESULTS AND CONCLUSIONS

Skin is in a continual state of renewal, placing a high demand on zinc-based enzymes and proteins that direct this process. The importance of zinc physiologically is especially evident in studies of wound healing and inflammation reduction. During these processes, the high needs for zinc can be supplemented externally, generally increasing the rates of the natural processes. Topical zinc delivery involves the pharmacologic optimization of zinc delivery, often mediated by the solubility of the zinc material and interactions within the product matrix.

Serum copper and zinc concentrations in patients with brucellosis

The aim of this study was to measure the alterations in serum trace element concentrations, including zinc (Zn) and copper (Cu) in patients with brucellosis and to compare them with the results of healthy individuals. Seventy-five subjects, 60 patients with brucellosis and 15 healthy individuals were included in this study. The serum Zn and Cu concentrations were measured by using atomic absorbtion spectrophotometer in sera of patients with brucellosis and statistically compared with those of healthy individuals. Serum Cu concentration was found to be significantly higher in patients with brucellosis than that of healthy individual (130.5+/-24.7, 96+/-8.65 microg/dl, respectively) (p < 0.01). Serum Zn concentration was lower in patients with brucellosis than those of healthy subjects (79.5 +/-13.5 and 83+/-5.59 microg/dl, respectively) (p < 0.01). Serum trace element concentrations showed significant alterations in patients with brucellosis compared with healthy subjects.

Does human betaA4 exert a protective function against oxidative stress in Alzheimer's disease?

The hypothesis is advanced that human betaA4--as opposed to rodent betaA4--may exert a protective function against the iron-induced oxidative stress associated with neurological diseases (notably Alzheimer's disease). Subsequent to its release by the host in response to oxidative injury, human betaA4 would interact with Cu(2+)ions whose level is correlatively elevated, adopting the 'aggregated' structure recently characterized by Atwood et al.(15). Then, depending on the oxidative state--hence the pH--of the medium, it might either return to its original structure if physiological pH is restored, or undergo site-specific copper-mediated oxidation and, finally, degradation. In this context, betaA4 pathogenicity could be due to an interfering mechanism preventing the degradation of the oxidized peptide, making its aggregation irreversible and inducing its final deposition. Coordination of side group oxygen donors of the oxidized peptide with 'hard' metal ions occurring in the physiological medium (notably Al(3+)) might be at the origin of this interference.

Copper and zinc body levels in inflammation: an overview of the data obtained from animal and human studies

The development of acute and chronic inflammatory processes induces, in the laboratory animal, a net accumulation of both copper and zinc in many body compartments, the inflamed area included. In rheumatoid arthritis, as well as in animal models, only plasma zinc concentration seems to be significantly correlated with disease severity, while the increase in total plasma copper could be described as an "all or nothing" phenomenon. Moreover, in rheumatoid arthritis, it appears that the disease develops and progresses without being linked to either copper or zinc deficiency conditions. Thus, it seems reasonable to suggest that a rationale for the use of copper and/or zinc in the treatment of inflammatory disorders can only be drawn from the intrinsic pharmacological properties of such trace elements, rather than from the need for their repletion.

Is copper pro- or anti-inflammatory? A reconciling view and a novel approach for the use of copper in the control of inflammation

The anti-inflammatory role of copper is well-known although still largely unexplained. On the other hand, the capacity of copper to induce the formation of damaging .OH radicals in vivo is no longer debated. These two aspects of the physiological activity of copper have been considered to be paradoxical. Arguments developed here show that they may actually derive from a single chemical process, the type of physiological effect observed depending on the ligand bound to the copper ions involved in Fenton chemistry. Both iron and copper are Fenton catalysts. Given its intrinsic coordination properties, however, copper induces more site-specific .OH damage to the ligands bound to it. It, therefore, appears that copper complexes with specific .OH-inactivating ligands (OILs) can be used as "lures" for the Fenton reaction, .OH radicals preferentially formed on these being immediately inactivated. The hypothesis is thus put forward here that copper-OIL complexes acting as effective Fenton catalysts are potential "catalase-like" anti-inflammatory drugs.

Effects of acute and chronic prednisolone treatment on serum zinc levels in rats with adjuvant arthritis

Several studies in animals and humans have independently demonstrated that zinc metabolism is significantly affected either by inflammation or by glucocorticoid administration. The relative importance of these two factors was assessed in this study by the investigation of the effects on serum zinc concentrations of acute and chronic prednisolone treatments in adjuvant arthritis rats and in healthy controls animals. Acute steroid administration (3 mg/kg, i.p.) caused a rapid drop in serum zinc followed by a quick recovery, regardless to the fact that these concentrations were normal (healthy animals) or already reduced by the inflammatory process. However, the modification occurred faster in inflamed animals. Chronic steroid administration (0.58 to 0.78 mg/kg/day during 1 to 4 weeks) had a more complex effect. A previous experiment in healthy rats demonstrated that such a treatment only induced a slight decrease in serum zinc. In adjuvant arthritis animals, the early steroid treatment of the induced process promoted a further decrease in serum zinc level while a delayed treatment did not result in additional changes.

The acute phase protein response during parasitic infection

There is a paucity of comprehensive studies of the APP response in parasitic infection. This should be remedied for two reasons. First, as there is a limited number of cytokines with hepatocyte-stimulating activities, and as each one elicits a unique spectrum of protein changes, examination of the APP response during infection could provide insight into the cytokines involved. Second, the presence of IL-1, IL-6 and TNF, the mediators of the APR, in tissues and circulation have important implications for subsequent immune responses.

Zinc monoglycerolate: a slow-release source of zinc with anti-arthritic activity in rats

Zinc repletion by parental administration of zinc monoglycerolate (ZMG) or certain other lipophilic zinc complexes, suppressed the development of adjuvant-induced polyarthritis in rats. While ZMG was effective when given parenterally over various limited time schedules (immunosuppressant, therapeutic, singledose), it was not effective given orally. The complex showed no acute anti-inflammatory activity in the carrageenan paw oedema assay and little gastric-intestinal or other organ toxicity. When injected s.c. it caused very much less local irritation than most zinc salts. Being lubrous, ZMG could be applied as the dry powder for rubbing into the skin and by this route was found to have anti-arthritic activity. 65Zn was shown to be absorbed and excreted in the faeces (biliary excretion) after applying 65Zn-ZMG dermally to shaved dorsal skin of rats. ZMG showed consistent anti-arthritic activity in rats under conditions in which 2 gold drugs (aurothiomalate, Auranofin) exhibited variable effects, depending on the strain of rat. The role of zinc and its availability in chronic inflammation are discussed on the basis of these studies.

Effects of copper aspirinate and aspirin on tissue copper, zinc, and iron concentrations following chronic oral treatment in the adjuvant arthritic rat

Concentrations of copper, zinc, and iron were analyzed and compared in a number of tissues of adjuvant arthritic rats following 22 d of chronic treatment (per os) with either vehicle, aspirin or copper aspirinate, at doses of 100 mg/kg, 200 mg/kg, or 400 mg/kg. Such chronic treatment resulted in a negative balance in copper, zinc, and iron in many tissues. Among the tissues examined, liver and kidney exhibited the greatest changes in metal concentrations; brain and skeletal muscle exhibited the least. Arthritis-induced changes in the concentrations of all three metals in the liver were reversed upon treatment with aspirin. Treatment with copper aspirinate, on the other hand, resulted in an extremely high accumulation of copper in the liver. Arthritis-induced changes in copper, zinc, and iron concentrations in the pancreas and copper concentration in the plasma were generally not reversed upon treatment with either aspirin or copper aspirinate. Among the three metals examined, the degree of change observed as a result of drug treatments was greatest for iron and least for zinc. Finally, it appeared that the effects of aspirin and copper aspirinate on tissue metal concentrations were independent of the antiarthritic effects of these compounds.

Changes in zinc, copper and selenium status during adjuvant-induced arthritis in rats

Trace elements such as zinc, copper and selenium are involved in the pathogenesis of inflammatory diseases. In order to obtain more information about the overall movements of these minerals during the evolution of an experimental chronic inflammatory process, trace element levels were determined in five body compartments of the rat at several time intervals after induction of adjuvant arthritis. Rapid and significant changes in plasma zinc and copper levels and in liver zinc levels were observed. These modifications occurred as early as those in biochemical parameters of inflammation such as serum fibrinogen and ceruloplasmin, and preceded the appearance of any clinical symptom of the disease. Inverse correlations were found between plasma zinc levels and these two biochemical indices. Other modifications in trace element levels were observed two weeks after disease induction, the most important being a considerable increase in liver copper levels. Although food intake of affected animals decreased with the progression of the disease, there was no evidence of depletion in zinc and copper levels over the study period. A redistribution of body zinc between different biological compartments (mainly plasma and liver) occurred simultaneously with an accumulation of copper in several organs. The decreasing selenium status of animals was not clearly related to the inflammatory process.

Copper and zinc status in rats with acute inflammation: focus on the inflamed area

Status of copper and zinc in plasma, blood cells, liver and hind paws (sectioned at the tibio-tarsal joint) were evaluated in rats with carrageenan-induced paw-oedema; moreover, concentrations of copper and zinc in the supernatant and cell fractions obtained from exudates pooled from rats with carrageenan-induced pleurisy were also determined. The evaluation of copper and zinc status in the blood and in the liver of rats with carrageenan-induced paw oedema, showed that only minor variations differentiated this experimental pathology from the previously studied carrageenan-induced pleurisy in rat. In inflammatory exudates withdrawn from pleural cavity, copper concentrations were found to be higher than the basal values measured in the whole paw, whereas zinc concentrations were found to be dramatically lower. Thus, the induction of the carrageenan paw-oedema determined an increase in copper and a decrease in zinc concentrations in the inflamed paw; however, in the inflamed paw, the total amounts of both copper and zinc were found to be significantly increased.

Copper and zinc status in adjuvant-arthritic rat: studies on blood, liver, kidneys, spleen and inflamed paws

The status of copper and zinc in plasma, blood cells, kidneys, spleen and hind paws was evaluated in tail-injected adjuvant-arthritic rats, during both the asymptomatic (3 and 7 days after the inoculum) and symptomatic (14, 21 and 30 days after the inoculum) phases of the experimental disease. During the symptomatic phase, inflamed rats were studied divided into two groups on the basis of their arthritic scores (low-score L.S. and high-score H.S. arthritic rats). Copper (both in concentration and total amount) was found significantly increased in plasma, blood cells, liver, spleen and arthritic paws, whereas, in the kidneys, it was found to be lower than normal. Zinc was found to be remarkably increased in the liver. In blood, zinc was found to be decreased in plasma, but almost unchanged in the cellular fraction. Zinc total amount (but not concentration) was increased in the spleen, most likely because of a significant increase in spleen weight. As previously described in the case of acute inflammation, zinc concentration was found to be significantly decreased in arthritic paws, whereas the total amount of the metal present in these inflamed tissues was higher than normal. The status of copper and zinc may well differentiate L.S. from H.S. arthritic rats, especially during the latest phase of the experimental disease, and particularly because of a normalization of the considered parameters in the low-score group. Many of the changes observed in the status of both metals were seen prior the appearance of arthritis. The overall accumulation of copper and zinc which is induced in rat by the development of adjuvant arthritis, is suggested to further sustain the hypothesis of increased body requirements for both metals during inflammation.