Interactions of copper and zinc in cardiovascular disease

Experimental and DFT characterization, antioxidant and anticancer activities of a Cu(II)-irbesartan complex: structure-antihypertensive activity relationships in Cu(II)-sartan complexes

The coordination compound of the antihypertensive ligand irbesartan (irb) with copper(II) (CuIrb) was synthesized and characterized by FTIR, FT-Raman, UV-visible, reflectance and EPR spectroscopies. Experimental evidence allowed the implementation of structural and vibrational studies by theoretical calculations made in the light of the density functional theory (DFT). This compound was designed to induce structural modifications on the ligand. No antioxidant effects were displayed by both compounds, though CuIrb behaved as a weak 1,1-diphenyl-2-picrylhydrazyl radical (DPPH(·)) scavenger (IC50 = 425 μM). The measurements of the contractile capacity on human mesangial cell lines showed that CuIrb improved the antihypertensive effects of the parent medication. In vitro cell growth inhibition against prostate cancer cell lines (LNCaP and DU 145) was measured for CuIrb, irbesartan and copper(II). These cell lines have been selected since the angiotensin II type 1 (AT1) receptor (that was blocked by the angiotensin receptor blockers, ARB) has been identified in them. The complex exerted anticancer behavior (at 100 μM) improving the activity of the ligand. Flow cytometry determinations were used to determine late apoptotic mechanisms of cell death. Experimental and DFT characterization of an irbesartan copper(II) complex has been performed. The complex exhibits low scavenging activity against DPPH(·) and significant growth inhibition of LNCaP and DU 145 prostate cancer cell lines. Flow cytometry determinations were used to determine late apoptotic mechanisms of cell death. This compound improved the antihypertensive effect of irbesartan. This effect was observed earlier for the mononuclear Cu-candesartan complex, but not in structurally modified sartans forming dinuclear or octanuclear Cu-sartan compounds.

IHD from copper deficiency: a unified theory

The theory, in brief outline here, implicating deficiency of Cu in the aetiology and pathophysiology of IHD explains more attributes of the disease than any other theory. This theory satisfies several of Hill's criteria of a half-century ago for deducing association between an environmental feature and presence of an illness. Most important is the temporal association between the rise of IHD and the decrease in dietary Cu since the 1930s along with a parallel increase in the supplementation of pregnant women with Fe, a Cu antagonist. There are more than eighty anatomical, chemical and physiological similarities between animals deficient in Cu and individuals with IHD. Few of these similarities have been produced by other dietary manipulations because feeding cholesterol induces Cu deficiency in animals. The most recent of these to be identified is decreased serum dehydroepiandrosterone. Some concomitant aspects of Cu metabolism and utilisation have been identified in other theories about heart disease: fetal programming, homocysteine, and Fe overload.

Dietary zinc intake is inversely associated to metabolic syndrome in male but not in female urban adolescents

OBJECTIVE

To evaluate the relationship of copper and zinc dietary intakes with metabolic syndrome (MetS) in adolescents.

METHODS

The sample consisted of 1,311 adolescents aged 11-16 years, and MetS definition by de Ferranti et al. was used. Nutritional intakes, anthropometrical and biochemical markers were measured.

RESULTS

In males, highest quartile of zinc intake was inversely associated with MetS without and with adjustment by covariables. Without adjustment, highest quartile of copper intake was inversely associated (marginal significance) with MetS, but with adjustment, the relationship was not maintained. Likewise in male gender, elevated waist circumference was the only MetS component inversely associated with highest quartiles of zinc (without and with adjustment) and copper (significant in crude analysis and marginal significant in adjustment by covariables) intakes. In the girls, only waist circumference was significant and inversely associated with highest quartiles of zinc and copper intakes but the association did not remain significant after adjustments.

DISCUSSION

In the adolescents of this study, zinc intake could be more associated to a clustering of anthropometric, vascular, and metabolic alterations than to these alterations separately, and also it is inversely related to this clustering (MetS). However, studies in other populations are necessary to confirm and explain the finding of exclusive association zinc intake-MetS in male gender adolescents. Further research is required to explore biomarkers of physiological processes (antioxidant function, blood flow regulation, and epigenetic modulation dependent of zinc) in relation to zinc intake and MetS in pediatric and adult populations.

Effect of type of muscle and Cu supplementation on trace element concentrations in cattle meat

Considering that meat is an important source of metals exposure to humans it is important to explore trace element concentrations in different types of muscles. Because of the demonstrated effect of Cu-supplementation on mineral status, the influence of Cu-supplementation was also evaluated. Samples of four different muscles (diaphragm, cardiac, semitendinous and pectoral, n=120) from beef calves receiving typical commercial diets Cu-supplemented (15 mg Cu(2)SO(4)/kg DM) and non-supplemented were taken and acid digested. The levels of non-essential (As, Cd, Hg, Pb and Sn) and essential (Co, Cr, Fe, Mn, Mo, Ni, Se and Zn) elements were analyzed by ICP-MS. The statistical analyzes included two way Anova, post hoc DHS Tukey and Spearman correlations. The most active and less fat containing muscles showed in general the highest essential and the lowest non-essential trace element accumulation. As and Hg muscular residues are indicative of animal exposure, however, in situations of an adequate mineral status, essential trace element concentrations in muscle are irrespective of the mineral status of the animal and could be possibly related to their own particular muscular metabolism. Cu-supplementation significantly reduced As but caused a significant decrease of Se, which could have significance for the animal's health.

Trace element status in Saudi patients with established atherosclerosis

BACKGROUND

Traditional coronary risk factors do not fully explain variations in the incidence of cardiovascular disease (CVD). Epidemiological studies have implicated perturbations in selenium, copper, and zinc metabolism in the aetiology of CVD. However, these studies have been principally undertaken in Caucasian populations, in whom trace element intake is generally sufficient.

METHOD

We have measured serum and urine selenium, copper, and zinc; and superoxide dismutase, glutathione peroxidase, and lipid peroxide concentrations in 130 Saudi male subjects with established CVD, and 130 age-matched controls.

RESULTS

Diabetes mellitus, positive smoking habit (p<0.0001 for both), and hypertension (p<0.05) were more prevalent among CVD patients. Urinary copper (p<0.0001) and zinc (p<0.05) were higher among controls. Serum selenium concentrations were lower among CVD patients (p<0.001), and a high proportion (52%) had selenium levels below 79mug/L compared to controls (22%) (p<0.0001). Conditional logistic regression analysis, showed the characteristics differentiating CVD patients from controls were serum zinc (odds ratio (OR) 0.92, confidence interval (CI) 0.85-0.99, p<0.05), serum copper/zinc ratio (OR 0.31, CI 0.10-0.96), serum selenium (OR 0.07, CI 0.02-0.31, p<0.0001), and urine selenium (OR 3.34, CI 1.40-7.99, p<0.01).

CONCLUSION

Measures of trace metals status appear to be associated with the risk of atherosclerosis in a Saudi male population.

The effects of coadministration of dietary copper and zinc supplements on atherosclerosis, antioxidant enzymes and indices of lipid peroxidation in the cholesterol-fed rabbit

It has previously been shown that dietary copper can modulate the extent of atherosclerosis in the thoracic aorta of cholesterol-fed rabbits. The metabolism of copper and zinc are closely related, and it has been hypothesized that the balance of dietary copper to zinc may be important in determining coronary risk. Hence, we have investigated the interaction between dietary copper and zinc in atherogenesis in the New Zealand White rabbit. Juvenile male rabbits were randomly allocated to eight groups. Four groups were fed a normal chow diet with zinc (0.5%, w/w), copper (0.2%, w/w), copper plus zinc or neither in their drinking water for 12 weeks. Four other groups were fed a diet containing 0.25-1% (w/w) cholesterol plus zinc, copper, both or neither. Serum cholesterol of individual animals was maintained at approximately 20 mmol/l. Integrated plasma cholesterol levels were similar for all groups receiving cholesterol and significantly higher than those in the chow-fed groups (P < 0.001). Aortic copper concentrations were higher in the animals receiving cholesterol diets with copper compared to rabbits receiving normal chow and copper (P < 0.001). Aortic zinc content was significantly higher in cholesterol-fed rabbits supplemented with zinc alone or with copper than in those fed cholesterol alone (P < 0.001). Plasma ceruloplasmin concentrations were significantly higher in groups receiving cholesterol, irrespective of their trace element supplementation (P < 0.001). However, trace element supplementation increased the level significantly (P < 0.05). Trace element supplements did not appear to affect erythrocyte superoxide dismutase in the cholesterol-fed animals; however, zinc supplementation was associated with a significant increase in the enzyme in chow-fed animals (P < 0.05). The activity of the enzyme per mg of protein in aortic tissue was higher in animals receiving copper in the presence of cholesterol (P < 0.05) but not significantly so in its absence. Dietary trace element supplementation in cholesterol-fed animals was associated with a significant reduction in aortic lesion area. Plasma thiobarbituric acid-reactive substances and FOX concentrations were both significantly higher in the cholesterol-fed rabbits compared with the animals that fed on a chow diet (P < 0.001), and these were reduced significantly by dietary copper or zinc supplementation (P < 0.001). Hence, dietary supplements of copper or zinc at the doses used both inhibited aortic atherogenesis in the cholesterol-fed rabbits, although there was no significant additional effect when given in combination.

Magnesium intake and risk of coronary heart disease among men

OBJECTIVE

Our aim in this study was to assess the relationship between magnesium intake and risk of coronary heart disease (CHD) among men.

METHODS

A total of 39,633 men in the Health Professionals Follow-up Study who returned a dietary questionnaire in 1986 were followed up for 12 years. Intakes of magnesium, zinc and potassium and other nutrients were assessed in 1986, 1990 and 1994. Total CHD incidence (nonfatal myocardial infarction (MI) and fatal CHD) was ascertained by biennial questionnaire and mortality surveillance confirmed by medical record review. Standard CHD risk factors were recorded biennially.

RESULTS

During 12 years of follow-up (414,285 person-years), we documented 1,449 cases of total CHD (1,021 non-fatal MI cases, and 428 fatal CHD). The age-adjusted relative risk (RR) of developing CHD in the highest quintile (median intake = 457 mg/day) compared with the lowest quintile (median intake = 269 mg/day) was 0.73 (95% CI 0.62-0.87, p for trend <0.0001). After controlling for standard CHD risk factors and dietary factors, the RR for developing CHD among men in the highest total magnesium intake quintile compared with those in the lowest was 0.82 (95% CI 0.65-1.05, p for trend = 0.08). For supplemental magnesium intake, the RR comparing the highest quintile to non-supplement users was 0.77 (95% CI 0.56-1.06, p for trend = 0.14).

CONCLUSIONS

These results suggest that intake of magnesium may have a modest inverse association with risk of CHD among men.

Hohenheim consensus workshop: copper

Copper (Cu) is an essential trace element with many physiological functions. Homeostatic mechanisms exist to allow Cu to act as a cofactor in enzymatic processes and to prevent accumulation of Cu to toxic levels. The aim of this commentary is to better understand the role of dietary Cu supply in deficiency and under physiological and pathological conditions. The essentiality of Cu can be attributed to its role as a cofactor in a number of enzymes that are involved in the defence against oxidative stress. Cu, however, has a second face, that of a toxic compound as it is observed with accumulating evidence in hepatic, neurodegenerative and cardiovascular diseases. The destructive potential of Cu can be attributed to inherent physico-chemical properties. The main property is its ability to take part in Fenton-like reactions in which the highly reactive and extremely deleterious hydroxyl radical is formed. Diseases caused by dietary Cu overload could be based on a genetic predisposition. Thus, an assessment of risk-groups, such as infants with impaired mechanisms of Cu homeostasis regarding detoxification, is of special interest, as their Cu intake with resuspended formula milk may be very high. This implies the need for reliable diagnostic markers to determine the Cu status. These topics were introduced at the workshop by the participants followed by extensive group discussion. The consensus statements were agreed on by all members. One of the conclusions is that a re-assessment of published data is necessary and future research is required.

Silicon bioavailability studies in young rapidly growing rats and turkeys fed semipurified diets: a comparative study

Two experiments were conducted using completely randomized designs to study the bioavailability of Si from three sources to growing rats and turkeys fed semipurified diets. The basal diets were dextrose-egg albumin for rats and dextrose-casein for turkeys. The Si sources were tetraethylorthosilicate (TES), sodium silicate (NaSil), and sodium zeolite A (NaZA). Rats and turkeys were supplemented at 500 and 270 ppm Si, respectively, from each source. A control group of unsupplemented rats and turkeys was included in each experiment. In general, irrespective of Si source, Si supplementation slowed (p < 0.05 or p < 0.01) growth rates in both rats and turkeys. Although dietary Si supplementation reduced (p < 0.05) plasma Mg levels and liver Zn concentrations in rats, it increased (p < 0.05) plasma P and reduced (p < 0.05) plasma Cu levels in turkeys. Rats on TES had significantly slower (p < 0.05 or p < 0.01) growth rates (5-10%) than those on NaSil or NaZA. In rats, NaZA and TES reduced (p < 0.05) hemoglobin concentrations and plasma Zn, respectively. However, plasma Mg levels were higher (p < 0.05) in TES than NaSil- or NaZA-fed rats. The source of the dietary Si did not affect (p < 0.05) the organ weights of rats and their mineral concentrations. Turkeys on TES diets grew at a significantly faster (p < 0.05) rate (15%) than those on NaSil or NaZA diets during the first 2 wk of experimentation. However, after 4 wk, there were no significant(p > 0.05) differences in growth between the Si sources. In turkeys, NaZA increased (p < 0.05) hematocrit levels and plasma Mg levels. Turkeys on NaZA diets had larger (p < 0.05) hearts and livers than those on NaSil but not TES. Liver Mn content was higher (p < 0.05) in turkeys on NaSil than TES or NaZA. Heart Zn was lower (p < 0.05) in turkeys on NaSil than TES, but not NaZA.

Copper/zinc ratio and systemic oxidant load: effect of aging and aging-related degenerative diseases

There is evidence that copper and zinc have pro-oxidant and antioxidant properties, respectively, so that their imbalance may be expected to condition oxidative stress status. Oxidative stress is relevant in aging and in age-related degenerative diseases. In this study, blood content of copper, zinc, and ceruloplasmin as well as of lipid peroxides were investigated in 81 healthy and 62 disabled octo-nonagenarians affected by chronic degenerative diseases, and in 81 healthy adults. Serum copper/zinc ratio and ceruloplasmin were significantly higher in the elderly than in the healthy adults. Moreover, all these parameters were significantly higher in the disabled than in the healthy elderly. Notably, the increased copper/zinc ratio found in healthy elderly was due to high copper values, whereas in the disabled, both high copper and low serum zinc concentrations were present. The copper/zinc ratio was significantly and positively related to systemic oxidative stress status in all groups. The higher the serum copper/zinc ratio the higher the lipid peroxides plasma content. We conclude that there is a strict relationship between copper/zinc ratio and systemic oxidant burden. Moreover, advanced age and, particularly, advanced age-related chronic degenerative diseases are associated with a significant increase in the copper/zinc ratio and systemic oxidative stress.

Copper-silicon interaction studies in young, rapidly growing turkeys fed semipurified starter diets

A 3x3 factorial experiment was conducted to study the interactions between Cu and Si in growing turkeys fed a basal dextrose-casein semipurified diet supplemented at 0, 270, and 540 ppm Si, and 2, 8, and 75 ppm Cu levels of inclusion. There were no significant (p>0.05) Cu, Si, or Cu-Si interaction effects on turkey growth. However, there were significant (p<0.05) Si effects on hemoglobin concentrations, and Cu-Si interaction effects on hematocrit and plasma Mg levels (p<0.01). Plasma Ca, P, Zn, Cu, total cholesterol, and serum alkaline phosphatase activity were not affected (p>0.05) by Cu, Si, or Cu-Si interaction. Heart and liver weights were affected (p<0.05) by the Cu-Si interaction. In general, a 8-ppm Cu supplemental level prevented cardiac hypertrophy only in the presence of 270 or 540 ppm Si inclusion in the diets. There were significant (p<0.05) Cu effects on liver Cu and Mn and heart Zn concentrations, Si effects on liver Mn levels, and Cu-Si interaction on liver Zn concentrations. Within the 0- and 270-ppm Si groups, Cu-deficient turkeys (2 ppm Cu) had higher liver Zn levels but not within the 540-ppm Si group. The Cu-Si interaction did not affect (p>0.05) concentrations of Cu in the heart and liver tissues. It is postulated that the Cu-Si interactions demonstrated in this study could have profound implications on the cardiovascular and skeletal health of birds.

The possible role of copper ions in atherogenesis: the Blue Janus

It has been proposed that the oxidative modification of low density lipoprotein (LDL) is a key event in human atherogenesis. Copper ions can catalyse the oxidative modification of LDL in vitro and there is some evidence that they may also participate in the oxidation of LDL within the arterial wall. However, copper ions also form an intrinsic constituent of superoxide dismutase and caeruloplasmin, enzymes that may be involved in preventing oxidative injury. Atherosclerotic lesions frequently contain considerable quantities of extracellular matrix molecules. These may contribute to the expansion of the arterial neointima, causing luminal narrowing. They may also play a beneficial role by stabilising the plaque. Copper is an essential component of lysyl oxidase, an enzyme involved in the biosynthesis of collagen, which is a major constituent of the extracellular matrix. The impact of alterations in body copper status on atherogenesis is therefore difficult to predict. Experimental and epidemiological data are conflicting and therefore do not provide a clear resolution of this issue. We have reviewed the biochemical and cellular effects of copper ions that may play a role in atherogenesis.

Protective effect of dietary fructo-oligosaccharide in young rats against exocrine pancreas atrophy induced by high fructose and partial copper deficiency

The objective of this investigation was to protect rats against exocrine pancreatic atrophy by adding 22% fructo-oligosaccharide (FOS), a natural fructan obtained from inulin, to the 50% copper-deficient diets containing qualitatively and quantitatively different carbohydrates. Young male Wistar rats were maintained on these diets for 10 wk, being weighed weekly then killed and autopsied. Major organs were weighed and histologically examined. Copper content in the diets was measured by flame atomic absorption spectroscopy. Incomplete (50%) copper deficiency avoided precocious mortality due to cardiovascular lesions and enabled another pathological condition to develop, consisting of the induction of exocrine pancreas atrophy. Introduction of gradually increasing percentages of fructose in diets at the level of 22, 42 and 62% induced a gradual increase in the copper-deficiency-mediated pathology in rats, expressed by an increase in exocrine pancreatic atrophy. 22% FOS introduced to the diet prevented the pathology induced by both fructose and partial copper deficiency better than starch added to diet at the level of 20 or 40%.

Effect of cuprofilin on experimental atherosclerosis

The effect of Cuprofilin, a newly synthesized C.(II)-chlorophyll complex, was assessed in rats with experimental atherosclerosis. The study was focused on changes in serum cholesterol, lipids, and triglycerides concentration as well as on serum and abdominal aorta Cu and Zn values. It has been ascertained that after 90 d in animals fed a rich lipid diet there was a statistically significant increase in serum cholesterol, triglycerides, and lipid concentration (p < 0.01). A significant augmentation of serum Cu values (p < 0.01) accompanied by a marked lowering of the same element in abdominal aorta (p < 0.01) was also found, as compared to the results registered in the control group. However, Cuprofilin, administered for 90 d in the group of animals with experimental atherosclerosis, significantly decreased the serum cholesterol, triglycerides, and serum lipid values (p < 0.01), increased copper content in aortic tissue (p < 0.01) and lowered serum copper concentration (p < 0.01) as compared to the untreated group. Moreover, in the aorta of administered animals the lipid infiltration has been demonstrated to be significantly diminished vs the untreated group.

Efficiency of serum copper/zinc ratio for differential diagnosis of patients with and without lung cancer

We examined serum copper (Cu), serum zinc (Zn), and the serum copper/zinc ratio (Cu/Zn) in 162 patients. All of them were seen to have an abnormal shadow in the chest X-ray films, that is, 109 patients with lung cancer (LC) and 53 patients with no lung cancer (NLC). The mean Cu and Cu/Zn in LC patients were significantly higher than those in NLC patients (p < 0.05). In LC patients, Cu and Cu/Zn were higher and Zn was lower in advanced tumors than early ones. There was a significantly clear relation between Cu or Cu/Zn and the tumor (T) stages. When the relative risk (RR) of LC was estimated, it was seen that the higher Cu and Cu/Zn became, the higher RR became. Furthermore, we showed the sensitivity of the receiver operator characteristic of the test (ROC) curve for Cu, Cu/Zn, and carcinoembryonic antigen (CEA) to diagnose LC, as explained in a paragraph of methods. The determinations of Cu, Zn, and Cu/Zn are simple and inexpensive. They also appear to have a great diagnostic value in determining the local invasion of LC and as a screening test in the high-risk patients for LC.

Hyperbaric hyperoxia exaggerates respiratory membrane defects in the copper-deficient rat lung

Scanning (SEM) and transmission electron microscopy (TEM) were used to examine the effect of dietary copper deficiency and hyperbaric hyperoxia, alone and in combination, on lung structure. Male, weanling Sprague-Dawley rats were fed a copper-deficient (CuD, 0.2 microgram/g) or copper-adequate diet (CuA, 5.1 micrograms/g). After 35-41 d on their respective diets, rats from each group were placed inside a pressure vessel kept at 27 degrees C under one of two pressure protocols. Air controls were maintained at 1 atm for 75 min. Rats exposed to oxygen were maintained at 1 atm of air plus 3 atm of oxygen for 1 h and then decompressed for 15 min. Under SEM, none of the treated lungs (CuD, CuA-O2 exposed, or CuD-O2 exposed) showed abnormal lung morphology from the conducting bronchioles down to the alveoli. Copper-deficient red blood cells were abnormally shaped. Under TEM, CuA-O2-exposed lungs showed thicker respiratory membranes, especially basement membranes and endothelial cells, and alveolar Type II cells having more than the usual number of surfactant vacuoles. CuD lungs also showed thicker endothelial and basement membrane components of the respiratory membrane, but normal looking Type II cells. CuD-O2-exposed lungs showed greatly thickened respiratory membranes and severe disruption of both endothelium and basement membrane and, judging by the increased number of nuclei per field, an increase in the number of both Type I and Type II cells. We conclude that copper deficiency enhances the damage caused by O2 toxicity, an effect that may be caused by reduced antioxidant status.

Silicon metabolism. The interrelations of inorganic silicon (Si) with systemic iron (Fe), Zinc (Zn), and copper (Cu) pools in the rat

The influence of silicon treatment on the levels of trace elements zinc (Zn), copper (Cu), and iron (Fe) in serum and tissues was studied in rats. The concentrations of silicon, iron, and zinc were estimated in samples of sera and tissues of rats receiving per os a soluble, inorganic silicon compound--sodium metasilicate nonahydrate (Na2SiO3.9H2O), dissolved in the drinking water. An increase of copper concentrations in liver and aortic walls in the experimental group was observed, with simultaneous reduction of zinc amounts in serum and all the tissue samples in the course of the experiment. The iron concentrations in the analyzed samples did not show any significant changes between both groups. The silicon levels in serum and in all the examined tissues were significantly higher in the tested group. The results provide evidence for the silicon interaction with copper and zinc, which could result in a number of metabolic process modifications, antiatheromatous activity among them.

Relation of serum zinc and copper to lipids and lipoproteins: the Yi People Study

The relations of serum zinc (Zn) and copper (Cu) to serum total cholesterol (TC), low-density-lipoprotein and high-density-lipoprotein cholesterol (LDL-C and HDL-C) and triglycerides were investigated in a population-based sample of 399 men in Southern China. Serum Cu was inversely related to HDL-C (r = -0.21), while Zn/Cu ratio showed a positive association (r = 0.19). These relationships remained significant after adjusting for age, body mass index (kg/m2), physical activity, tobacco smoking and dietary cholesterol, fat, and fiber. While no significant association was observed between serum Cu and serum TC in univariate analysis, a significant negative association was observed in multivariate analysis, after adjustment for the above mentioned independent variables. No significant association between serum Cu and LDL-C was found. These observations, as well as those reported in other studies reviewed herein, suggest that Cu is implicated in the metabolism of HDL-C, although the mechanism involved is not fully understood. No significant associations were found between serum Zn and the lipid variables.

Copper and zinc in experimental hypertension

The role of the trace minerals, copper (Cu) and zinc (Zn) are important in maintaining blood pressure. Copper has been found to inhibit the activity of angiotensin's converting enzyme. An interrelationship has been found to exist between Cu and Zn. Data in renal (RH) and spontaneous hypertensive rates (SHR) regarding Cu and Zn is lacking. The purpose of this report was to measure Cu and Zn levels in two types of experimental animal models of hypertension compared to normotensive (NT) rats. Blood samples were drawn to measure serum levels of Cu and Zn in three types of animals, RH, SHR, and NT. Serum Cu values were found to be lower, whereas Zn levels were elevated in the SHR animals. Serum levels of Cu and Zn in the RH animals were similar to those found in the NT animals. Further study of the interaction of those trace minerals is documented, and extends over knowledge of the role of minerals in blood pressure control.

Serum zinc and copper: associations with cholesterol and triglyceride levels in children and adolescents. Cardiovascular risk in young Finns

Associations among serum lipids (total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglycerides) and levels of serum zinc (S-Zn), serum copper (S-Cu), and their ratio were analyzed in 3373 3-, 6-, 9-, 12-, 15-, and 18-year-old Finnish girls and boys. S-Zn was positively related to total cholesterol, HDL-cholesterol, and LDL-cholesterol; S-Cu related negatively to HDL-cholesterol. Obesity did not affect these relationships. The few exceptionally high lipid levels found were not associated with very low or high S-Zn or S-Cu. S-Zn and S-Cu were related to serum lipids; causality between the variables, however, remains to be studied.

Ischemic heart disease as copper deficiency

Atherosclerosis is a complex process beginning early in life and often leading to death from ischemic heart disease in middle age. Hundreds of factors are said to contribute to this risk. More than 50 similarities between animals deficient in copper and people with ischemic heart disease have been identified. Some of the more important characteristics of this illness have been produced in experiments in which men and women were fed diets low in copper. Diets with similarly low amounts of copper are readily available to the population at large. More aspects of the anatomy, biochemistry, chemistry, epidemiology, pathogenesis and pathophysiology of ischemic heart disease can be explained by considering this illness to be a problem of copper deficiency than by considering any of several other explanations that have been offered.

Roles of copper in bone maintenance and healing

This review is intended to focus attention on the importance of essential metallo-element metabolism, particularly copper metabolism, as an important component of normal bone metabolism in maintenance and repair. Literature published since Rademacher's early (1) astute observation that copper supplementation increases the rate of bone healing documents and explains key roles of copper-dependent processes required for maintenance and repair of this tissue. State of the art approaches to treatment of bone diseases including lengthening of bone and repair of fractures, can be improved by paying closer attention to the roles of copper and other essential metallo-elements required for optimal treatment.

Dietary cholesterol lowers liver copper in rabbits

Atherosclerosis and hypercholesterolemia have been produced in rabbits since 1913 by feeding them cholesterol. These experiments have a great influence on current thinking about the etiology and possible prevention of ischemic heart disease. Male, New Zealand White rabbits were fed 0.5% dietary cholesterol. Cholesterol and copper in plasma increased sixty-fold and 50%, respectively. Liver copper decreased 74% and hematocrit decreased 26%. Iron was unchanged in heart and liver, but was increased in kidney. Zinc was decreased in heart, but was unchanged in liver or kidney. Changes in organ iron and zinc were smaller than the decrease in liver copper. Similar experiments with higher doses of dietary cholesterol may have resulted in copper deficiency. It may be appropriate to revise interpretations of data from these experiments and to reformulate hypothesis based on the data. Results are consonant with the theoretical implication of copper metabolism and copper deficiency in the etiology and pathogenesis of ischemic heart disease.

Selenium: geochemical distribution and associations with human heart and cancer death rates and longevity in China and the United States

The geochemistry of available soil Se varies enormously in different localities, and the corresponding amounts moving up through crops to food vary accordingly. In a belt extending from northeastern to south central China, the available soil Se was measured by human blood Se levels. Severe deficiency occurred at 8-26 ng/mL; subadequate amounts occurred in large areas with 32-83 ng/mL; adequate amounts of 200-300 ng/mL occurred in large cities; and toxic amounts of 3000-7800 ng/mL occurred in terrace areas where runoff from the uplands evaporated, and in certain other soils. Some heart deaths (Keshan Disease) occurred in children 1 to 10 yr of age in the most deficient areas, but were prevented by 230-900 micrograms/wk Se supplementation. One mg Se/wk was the adult dosage. In Se deficient areas, the life span of adults was lowered severely (35 to 45 yr), with heart muscle damage common at autopsy. Se and Zn deficiencies are apparently associated with stomach cancer. The geochemistry of Se in the USA is also highly variable, blood Se ranging from 100-350 ng/mL. Se data for individuals are limited; however, ischemic heart death correlated inversely with blood Se in 25 cities of 22 states (r = -.70; p less than .01). Counties of Wisconsin and Florida are highly variable in human heart death and cancer death rates, as are the 50 states, suggesting Se geographic variability.

Zinc in human health and disease

The importance of zinc in human health and disease has been reviewed by reporting data from the recent literature. The role of zinc in human nutrition, general health, skin diseases, acrodermatitis enteropathica, reproductive physiology and pathophysiology, pregnancy, non-insulin-dependent diabetes mellitus as well as atherosclerosis is discussed. The consequences of zinc deficiency and toxicity are also illustrated.

Dietary copper: a powerful determinant of cholesterolemia

A new hypothesis suggests that deficiency of copper is important in the etiology and pathophysiology of ischemic heart disease. Several chemicals, called cholesterotropic and cuprotropic, that affect cholesterolemia also affect copper metabolism. Responses to some of these chemicals that have been tested in humans were compared on a molar basis. Dietary copper was approximately one hundred times as active in lowering cholesterol in plasma than was clofibrate which, in turn was six times as active as dietary fat. Dietary copper may be a powerful determinent of cholesterolemia.

Atrial thrombosis, abnormal electrocardiograms and sudden death in mice due to copper deficiency

Approximately 20 years ago a diet high in lard and sucrose was described that produced extensive cardiovascular damage in adult mice. Atrial thrombosis, myocardial necrosis and sudden death were frequent. These experiments were repeated as closely as possible; the adverse effects were prevented by a drinking solution containing 10 micrograms copper/ml. Lack of copper also was associated with anemia, cardiac enlargement and abnormal electrocardiograms. Bradycardia, coupled beats, ectopic ventricular foci, premature atrial beats and prolonged PR interval were found. Lack of copper had no effect on cholesterol in plasma. The results may be germane to ischemic heart disease and the thrombotic susceptibility of women who use oral contraceptives or are pregnant frequently, because copper metabolism is altered in these conditions.

Biochemical, metabolic, and clinical role of copper in human nutrition

Veterinary nutritional science has embraced the study of copper for decades, but copper has languished as an orphan among human nutritionists because of the obscurity of clinical copper-deficiency states in man. As medical investigators, we may have gone down a long road, missing the forest for the trees. Indeed, overt copper-deficiency syndromes in humans have been recognized since the 1960s, and the list of contributing factors is expanding. Unwise self-medication with megadoses of zinc, for instance, might produce a mini-epidemic of copper deficiency. Moreover, induced copper deficiency may someday prove to be a legitimate therapeutic intervention in some disease states. But, the influence of subtle differences in dietary intakes of copper on human health may be much more important than frank copper depletion. Moreover, the recognition of disordered copper metabolism simulating a deficiency state--as occurs in Menkes' KHS and in variant Elhers-Danlos syndrome--has important implications. The full description of the relationship that thionein and other intracellular proteins might have in the etiology of these alterations has yet to be written. The elegance of the interplay of biochemical defects, physiological dysfunction, and clinical manifestations in copper metabolism is virtually unmatched in nutritional biology; yet, our present abilities to determine human copper status are limited. Now that it is clear that intracellular redistribution as well as total-body depletion can effect the disruption of copper-dependent functions, a concerted effort to improve status assessment through the use of functional indices should become a high priority. Finally, the pursuit of the bases of copper's involvement in host defenses, antiotoxidant protection and carbohydrate metabolism--functions in which clear links to established mammalian cuproenzyme are at present elusive--should provide exciting substrate for investigators for years to come.

Increased cholesterol in plasma in a young man during experimental copper depletion

Signs of copper depletion were produced in a healthy man by an amount of dietary copper (0.83 mg/day) similar to that in some contemporary diets. Urinary and fecal loss of copper exceeded intake. Plasma copper, ceruloplasmin, and superoxide dismutase activity in erythrocytes decreased. Cholesterol in plasma increased, and hematologic indices were unchanged. Lipid metabolism may be a more sensitive index of copper nutriture than are changes in hematology. The findings support the hypothesis that inadequate copper nutriture or altered copper metabolism contributes to the occurrence of ischemic heart disease.

Brain trace element concentrations in aging

Trace element concentrations were determined in various human brain regions over the complete life span using instrumental neutron activation analysis. Several different patterns of trace element alteration were observed with age. Brain Al, Cl and Na concentrations increase with advancing age, while K, P and Rb decline. Ag, Co, Fe, Sb and Sc concentrations increase up to the 40 to 79 age range then decline. Br, Se and Zn remain relatively constant throughout adult life. Hg, Mn and Cs show no consistent trend with age. In infant brains Br and Cl increase and Al, Cr, Cs, Fe, Mn, P, Rb, Sc, Se and Zn decrease compared to adults. The essential elements that remain within narrow concentration limits throughout adult life suggest the presence of an efficient homeostatic mechanism for their regulation in the brain, while those that are altered with age suggest modifications in control mechanisms or altered relationships with other elements. Increased concentrations of non-essential elements may reflect accumulation from our environment, impaired removal or altered balance with other elements.

Copper and ischemic heart disease

Absolute or relative deficiency of copper is hypothesized to be of prime importance in the etiology of ischemic heart disease. According to recent estimates, only 25% of the diets in the United States contain the 2 mg of copper thought to be required daily by adults. Some of these diets have ratios of zinc to copper greater than those that have produced hypercholesteremia in animals. There are many epidemiologic associations between the ratio of zinc to copper and dietary characteristics, organ analyses, clinical status, and environmental features that relate the metabolism of these elements to the anatomy, chemistry, pathology, pharmacology, and physiology of ischemic heart disease. Animals deficient in copper or exposed to a high dietary ratio of zinc to copper, which can produce a relative copper deficiency, are hypercholesteremic and hyperuricemic, and have glucose intolerance and abnormalities of the electrocardiogram. Their hearts and arteries have abnormal connective tissue, lipid deposits, and inflammatory changes; they die suddenly, often with ruptured hearts. Hypercholesteremia and glucose intolerance have been found in men depleted of copper and in children with Menkes' disease, an inability to absorb copper.

Blood pressure in young adults as influenced by copper and zinc intake

The relationship of copper and zinc status with blood pressure in young adults was studied (N=59). Copper and zinc status was assessed through analysis of serum, urine, hair, and diet records. Males (N=27) had greater systolic and pulse pressures than females (N=32). Multiple regression analysis suggested that males and higher caloric and dietary copper intakes were the predominant factors associated with higher systolic and diastolic pressures, whereas higher dietary zinc intakes were associated with lower pressures. Higher urine zinc excretion rates and serum zinc concentrations were associated with higher diastolic pressures. The sex variable was the strongest factor affecting pulse pressures, with males having higher pulse pressures. Serum zinc concentrations had an inverse relationship to pulse pressures. The data suggest that the weight/height index and age had a low association with blood pressure in this normotensive sample.

Serum lipids and glucose as associated with hemoglobin levels and copper and zinc intake in young adults

The association of copper and zinc intake with serum total cholesterol, HDL-cholesterol, triglycerides, and glucose concentrations were studied in young adults (N=59). Three-day diet records, hair, fasting blood, and overnight urine samples were collected from each subject. Higher hemoglobin concentrations, diet zinc intake, and serum copper:zinc ratios were associated with lower HDL-cholesterol concentrations. Higher hemoglobin and hair copper concentrations were associated with higher cholesterol concentrations. Higher serum copper concentrations were associated with higher triglyceride concentrations and with lower glucose concentrations. Greater hematocrits were associated with lower triglyceride concentrations. Hemoglobin levels had the strongest relationship with cholesterol and HDL-cholesterol. These results appeared inconsistent with the hypothesis on copper:zinc imbalance and reports from animal studies.

Ceruloplasmin, a copper-transport protein, can act as a growth promoter for some cell lines in serum-free medium

Ceruloplasmin (Cp) is a copper-transport protein with ferric oxidase activity found in high concentrations in the plasma of all vertebrates. Five cell lines (TR-1, TR-M, TR-ST, TM3, and TM4) derived from the testis can be grown in hormone-supplemented serum-free medium. Cp stimulates the growth of four of these five cell lines in serum-free medium. The growth stimulation by Cp is not affected by the addition or deletion of free copper, nor does copper itself elicit any significant growth response. Cp can stimulate growth also in the absence of TF suggesting that it is not acting solely to promote Fe(III)-TF binding. A strong interaction is seen between Cp and high density lipoprotein (HDL), with the presence of either decreasing the growth-promoting activity of the other. It is suggested that these cell lines may provide an ideal system for studying the action of Cp at the cellular level.

Interactions among nickel, copper, and iron in rats : Liver and plasma content of lipids and trace elements

In two fully crossed, three-way, two by three by three, factorially arranged experiments, female weanling rats were fed a basal diet supplemented with iron at 15 and 45 μg/g, nickel at 0, 5, and 50 μg/g and copper at 0, 0.5, and 5 μg/g (Expt. 1) or 0, 0.25, and 12 μg/g (Expt. 2). Expt. 1 was terminated at 11 weeks, and Expt. 2 at 8 weeks because, at those times, some rats fed no supplemental copper and the high level of nickel began to lose weight, or die from heart rupture. The experiments showed that nickel interacted with copper and this interaction was influenced by dietary iron. If copper deficiency was neither very severe or mild, copper deficiency signs of elevated levels of total lipids and lipid phosphorus in liver and plasma, and cholesterol in plasma, were made more severe by supplemental dietary nickel. Rats in which nickel supplementation exacerbated copper deficiency did not exhibit a depressed level of copper in liver and plasma. Also, although iron deprivation enhanced the interaction between nickel and copper, iron deprivation did not significantly depress the level of copper in liver and plasma. The findings confirmed that, in rats, a complex relationship exists between nickel, copper, and iron, thus indicating that both the iron and copper status of experimental animals must be controlled before data about nickel nutriture and metabolism can be compared among studies.