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1.
The hypothesis that nonenzymatic glycosylation of proteins (glycation) contributes to damage associated with dietary copper deficiency has depended largely on indirect evidence. Thus far, the observation of an elevated percentage of glycated hemoglobin in copper-deficient rats has provided the only direct evidence of an increase in glycation. We sought further direct evidence of increased glycation in copper deficiency. Male weanling rats were fed a copper-adequate (CuA, 6.4 mg Cu/kg diet) or copper-deficient diet (CuD, 0.4 mg Cu/kg diet) for 5 weeks. Rats fed the CuD diet were copper deficient as judged by depressed organ copper concentrations and a variety of indirect indices. Measurements of hemoglobin A(1) and serum fructosamine (both early glycation end-products) as well as serum pentosidine (an advanced glycation end-product) indicated that all three compounds were elevated in CuD rats relative to CuA rats. This finding further supports the view that glycation is enhanced and thus may contribute to defects associated with dietary copper deficiency.  相似文献   

2.
Dietary copper is an essential trace element with roles in both functional and structural aspects of the cardiovascular system. In particular, the vascular response to inflammatory stimuli is known to be significantly augmented in copper-deficient rats. The current study was designed to quantify the extent of injury-induced neointimal proliferation and stenosis in rats fed diets either adequate or deficient in copper. Male, weanling Sprague-Dawley rats were fed purified diets that were either adequate (CuA; 5.6 microg Cu/g) or deficient (CuD; 0.3 microg Cu/g) in copper for 4 weeks. Balloon injury was induced in the left external carotid arteries. Fourteen days after injury, histomorphometric analysis of cross-sections from carotid arteries showed increased neointimal formation in the CuD group compared with the CuA controls (neointima/media ratio: 4.55 +/- 0.93 vs 1.45 +/- 0.2, respectively). These results correspond with data indicating that the activity of Cu/Zn-superoxide dismutase (SOD) is depressed in rats fed this CuD diet. Because superoxide anion and redox status are known to play a key role in the extent of neointimal formation in response to injury, we propose that the exaggerated neointimal proliferation seen in the CuD group is the result of the diminished Cu/Zn-SOD activity.  相似文献   

3.
Dietary copper deficiency increases the accumulation of circulating neutrophils in the rat lung microcirculation. This process includes neutrophil adhesion to, migration along, and emigration though the vascular endothelium. The current study was designed to examine the role of copper in each of these steps. Neutrophils were isolated from rats fed either a copper-adequate (CuA, 6.1 microg Cu/g diet) or copper-deficient diet (CuD, 0.3 microg Cu/g diet) for 4 weeks. First, transient and firm adhesion of neutrophils to P-selectin in a flow chamber showed there were more adhered CuD neutrophils than CuA ones. This effect is probably caused by the increased expression of CD11b that was observed in the current study. Second, the evaluation of neutrophil migration under agarose showed that the CuD neutrophils moved farther than the CuA group in response to IL-8 but not fMLP; this suggests an increased sensitivity to a CD11/CD18-independent signalling pathway. Third, the contractile mechanism of endothelial cells was studied. Elevated F-actin formation in Cu-chelated lung microvascular endothelial cells suggests that neutrophil emigration may be promoted by enhanced cytoskeletal reorganization of the endothelium during copper deficiency. Combined, these results support the theory that dietary copper deficiency has proinflammatory effects on both neutrophils and the microvascular endothelium that promote neutrophil-endothelial interactions.  相似文献   

4.
Copper (Cu) deficiency in rats reduces the relative concentration of duodenal hephaestin (Hp), reduces iron (Fe) absorption, and causes anemia. An experiment was conducted to determine whether these effects could be reversed by dietary Cu repletion. Five groups of eight weanling male rats each were used. Group 1 was fed a Cu-adequate diet (5.0 mg Cu/kg; CuA) and Group 2 was fed a Cu-deficient diet (0.25 mg Cu/kg; CuD) for 28 days. The rats were fed 1.0 g each of their respective diets labeled with 59Fe (37 kBq/g), and the amount of label retained was measured one week later by whole-body-counting (WBC). Group 3 was fed a CuA diet and Groups 4 and 5 were fed a CuD diet for 28 days. Group 5 was then fed the CuA diet for another week while Groups 3 and 4 continued on their previous regimens. Rats in Groups 3, 4, and 5 were fed 1.0 g of diet labeled with 59Fe, and the amount of label retained was measured by WBC one week later. Rats were killed and duodenal enterocytes isolated for Hp protein analysis, whole blood was analyzed for hematological parameters, and various organs for 59Fe content. CuD rats absorbed less (P<0.05) Fe than CuA rats, the relative amount of duodenal Hp was less (P<0.05) in CuD rats, and the CuD rats developed anemia. After the CuD rats had been repleted with Cu for one week, Fe retention rose to values even higher (P<0.05) than those in CuA rats. After two weeks, the relative amount of duodenal Hp was higher (P<0.05) than normal, and most signs of anemia were reversed. Liver 59Fe was elevated in CuD rats, but was restored to normal upon Cu repletion. These findings suggest a strong association between duodenal Hp abundance and Fe absorption in the CuD rat, and that reduced Fe absorption is an important factor in the cause of anemia.  相似文献   

5.
The goal of this study was to determine the effects of Fe supplementation on the anemia of Cu deficiency in rats. In addition, we observed changes in serum and organ Cu and Fe during the development of Cu deficiency. In Experiment 1, weanling male Sprague-Dawley rats were fed AIN-93G diets containing either <0.3 mg Cu [Cu deficient (CuD)] or 6.0 mg Cu [Cu adequate (CuA)] per kilogram diet, and 35 mg Fe/kg. Five rats from each group were killed at intervals for the analysis of hematologic parameters and mineral content of various organs. In Experiment 2, two groups of 24 rats each were fed either the CuA diet or the CuD diet for 14 days. Then, three sets of eight rats in each group received three separate Fe treatments: (1) daily intraperitoneal injections of 400 mug Fe (Cu-free ferric citrate) per rat for another 14 days, (2) fed similar diets that contained three times the normal amount of Fe (105 mg/kg) for 14 days, or (3) received no further Fe treatment. At day 21, all rats were fed a 1-g meal labeled with (59)Fe to determine Fe absorption. After 28 days, rats were killed for the analyses of Fe and Cu status. Results of Experiment 1 showed that within 14 days, CuD rats had lower blood hemoglobin (Hgb), red blood cell count, and mean corpuscular volume than CuA rats. Copper concentrations in all tissues measured were lower in the CuD rats than in controls. Serum ceruloplasmin (Cp) activity in CuD rats was only 0.8% of CuA rats at day 7. During this period, enterocyte and liver Fe concentrations were elevated and serum Fe was reduced, but there was no change in spleen Fe. Results of Experiment 2 showed that CuD rats absorbed less Fe than CuA rats. Supplemental Fe by diet or by intraperitoneal injections did not prevent anemia in the CuD rats or affect other parameters of Cu status. Serum total iron binding capacity [transferrin (Tf)] was not changed by Cu deficiency or by Fe supplementation; however, percent Tf saturation was reduced in CuD rats but was not enhanced by Fe supplementation. These data suggest that anemia of Cu deficiency occurs because of reduced Fe absorption, and it inhibits release of Fe from the liver and inefficient loading of Fe into Tf because of very low plasma Cp activity. The latter then leads to inefficient delivery of Fe to the erythroid cells for heme and Hgb synthesis.  相似文献   

6.
The lymphatic absorption of cholesterol and plasma clearance of chylomicrons were investigated in Cu-deficient rats (CuD) fed 0.5 mg Cu/kg diet, as compared with Cu-adequate control rats (CuA) fed 7.5 mg/kg diet. Cholesterol absorption was measured by the 14C-radioactivity appearing in the mesenteric lymph at hourly intervals for 8 hr after an intraduodenal dose of [14C]cholesterol. The plasma clearance of chylomicrons was measured at 3, 6, and 10 min after an intravenous dose of chylomicrons labeled in vivo with [3H]retinyl ester. Cumulative [14C]cholesterol absorption and total lymphatic output of cholesterol were significantly decreased in CuD at 4 hr and thereafter, with no change in percentage distribution of free and esterified cholesterol. Over an 8-hr period, 7.3% of the dose was absorbed by CuD and 9.2% by CuA. When [3H]chylomicrons, obtained from a CuD or CuA donor rat, were injected into CuD and CuA recipient rats, the label was cleared faster in CuD during the first 3 min. At 6 and 10 min, however, no significant difference in percentage clearance of the dose was observed between the groups. The half-life (t1/2) of [3H]chylomicrons and the total 3H-radioactivity taken up by the liver during the entire 10-min period did not differ between the groups, regardless of the source of chylomicrons. The activities of both endothelial lipoprotein lipase (LPL) and hepatic lipase (HL) in postheparin plasma were markedly lower in CuD. As expressed in micromoles fatty acid released/hr/ml plasma, the activities of LPL in CuD and CuA were 32.6 +/- 1.9 and 45.6 +/- 1.3, respectively. A similar magnitude of difference was also observed in HL activity. The data provide evidence that copper deficiency impairs the intestinal transport of cholesterol and the peripheral lipolysis of chylomicrons. The data, however, strongly suggest that the hepatic uptake of chylomicron remnants via the apo-E-dependent mechanism may not be impaired in Cu deficiency.  相似文献   

7.
Inadequate dietary copper is known to result in undesirable metabolic changes in rats and humans. Abnormal cardiac function, leading to sudden death, is a common finding when copper deficient rats are fed a 62% fructose diet. To further study the apparent mineral-carbohydrate relationship to cardiac physiology, 3 male and 3 female swine were randomly assigned to four groups (6 pigs per group) which were fed low copper (1.5 ppm) or copper supplemented (40 ppm) diets with 20% of calories from either fructose or glucose for 10 weeks. In agreement with results from other animal studies, copper deficient swine exhibited decreased plasma ceruloplasmin, erythrocyte superoxide dismutase and plasma lysyl oxidase activities and lowered serum copper. The copper deficient fructose group had the lowest aortic lysyl oxidase activity and hematocrit when compared to the other groups. The relative heart weight in the copper deficient fructose group was 93% greater than the other three dietary groups. The livers of copper deficient fructose fed pigs were also significantly larger. Two enzymes related to cardiac and hepatic function, aspartate and alanine aminotransferase were also measured. Copper deficiency significantly lowered alanine aminotransferase but there was no dietary effect on aspartate amino-transferase. The results of this project indicate that the pig is a sensitive model for the study of cardiovascular abnormalities which occur when fructose is consumed with a low copper diet.  相似文献   

8.
9.
The present study was undertaken to measure the activities of several hepatic enzymes of regulatory importance in the pathways of lipogenesis and gluconeogenesis in rats fed diets marginally deficient in copper (1.2 micrograms Cu/g of diet) and containing either fructose, glucose, or starch as the carbohydrate sources. Although all copper-deficient rats exhibited the characteristic signs of copper deficiency, they were more pronounced in rats fed the diet containing fructose. Except for the activity of phosphoenolpyruvate carboxykinase which was unaffected either by copper deficiency or by the type of dietary carbohydrate, the hepatic activities of glucose-6-phosphate dehydrogenase, malic enzyme, L-alpha-glycerophosphate dehydrogenase and fructose 1,6-diphosphatase were unaffected by copper deficiency but were affected by the type of carbohydrate in the diet. Fructose produced the greatest increase in enzymatic activities, whereas starch produced the least activity and glucose induced an intermediate effect. These results indicate that the deleterious effects of a fructose diet deficient in copper on biochemical and physiological indices could not be due to an immediate metabolite of fructose. However, the involvement of a subsequent metabolite of fructose in the mechanism of copper utilization and/or requirement cannot be excluded.  相似文献   

10.
Copper deficiency was induced in rats by feeding diets containing either 62% starch, fructose or glucose deficient in copper for 6 weeks. All copper deficient rats, regardless of the dietary carbohydrate, exhibited decreased ceruloplasmin activity and decreased serum copper concentrations. Rats fed the fructose diet exhibited a more severe copper deficiency as compared to rats fed either starch or glucose. The increased severity of the deficiency was characterized by reduced body weight, serum copper concentration and hematocrit. In all rats fed the copper adequate diets, blood pressure was unaffected by the type of dietary carbohydrate. Significantly reduced systolic blood pressure was evident only in rats fed the fructose diet deficient in copper. When comparing the three carbohydrate diets, the physiological and biochemical lesions induced by copper deprivation could be magnified by feeding fructose.  相似文献   

11.
The hypothesis was tested that dietary fructose vs glucose lowers copper solubility in the digesta in the small intestine of rats, which in turn causes a decreased copper absorption. Male rats were fed adequate-copper (5 mg Cu/kg) diets containing either fructose or glucose (709.4 g monosaccharide/kg) for a period of 5 wk. Fructose vs glucose significantly lowered copper concentrations in plasma and the liver, but did not alter hepatic copper mass. Fructose feeding resulted in a significantly lesser intestinal solubility of copper as based on either a smaller soluble fraction of copper in the liquid phase of small intestinal contents or a lower copper concentration in the liquid phase. The latter fructose effect can be explained by the observed fructose-induced increase in volume of liquid phase of intestinal digesta. After administration of a restricted amount of diet extrinsically labeled with64Cu, rats fed fructose also had significantly lower soluble64Cu fraction in the digesta of the small intestine. Although this study shows that fructose lowered intestinal copper solubility, only a slight reduction of apparent copper absorption was observed. It is suggested that the fructose-induced lowering of copper status in part counteracted the fructose effect on copper absorption at the level of the intestinal lumen.  相似文献   

12.
Ceruloplasmin (Cp) is a multicopper oxidase and the most abundant copper binding protein in vertebrate plasma. Loss of function mutations in humans or experimental deletion in mice result in iron overload consistent with a putative ferroxidase function. Prior work suggested plasma may contain multiple ferroxidases. Studies were conducted in Holtzman rats (Rattus norvegicus), albino mice (Mus musculus), Cp?/? mice, and adult humans (Homo sapiens) to investigate the copper–iron interaction. Dietary copper-deficient (CuD) rats and mice were produced using a modified AIN-76A diet. Results confirmed that o-dianisidine is a better substrate than paraphenylene diamine (PPD) for assessing diamine oxidase activity of Cp. Plasma from CuD rat dams and pups, and CuD and Cp?/? mice contained no detectable Cp diamine oxidase activity. Importantly, no ferroxidase activity was detectable for CuD rats, mice, or Cp?/? mice compared to robust activity for copper-adequate (CuA) rodent controls using western membrane assay. Immunoblot protocols detected major reductions (60–90%) in Cp protein in plasma of CuD rodents but no alteration in liver mRNA levels by qRT-PCR. Data are consistent with apo-Cp being less stable than holo-Cp. Further research is needed to explain normal plasma iron in CuD mice. Reduction in Cp is a sensitive biomarker for copper deficiency.  相似文献   

13.
Previous studies have shown that cardiac-specific overexpression of metallothionein (MT) inhibits progression of dietary copper restriction-induced cardiac hypertrophy. Because copper and zinc are critically involved in myocardial response to dietary copper restriction, the present study was undertaken to understand the effect of MT on the status of copper and zinc in the heart and the subsequent response to dietary copper restriction. Dams of cardiac-specific MT-transgenic (MT-TG) mouse pups and wild-type (WT) littermates were fed copper-adequate (CuA) or copper-deficient (CuD) diet starting on the fourth day post delivery, and the weanling mice were continued on the same diet until they were sacrificed. Zinc and copper concentrations were significantly elevated in MT-TG mouse heart, but the extent of zinc elevation was much more than that of copper. Dietary copper restriction significantly decreased copper concentrations to the same extent in both MT-TG and WT mouse hearts, and decreased zinc concentrations along with a decrease in MT concentrations in the MT-TG mouse heart. Copper deficiency-induced heart hypertrophy was significantly inhibited, but copper deficiency-induced suppression of serum ceruloplasmin or hepatic Cu,Zn-SOD activities was not inhibited in the MT-TG mice. These results suggest that elevation in zinc but not in copper in the heart may be involved in the MT inhibition of copper deficiency-induced cardiac hypertrophy.  相似文献   

14.
The present study was designed to determine whether the supplementation of vitamin E in the copper-deficient diet would ameliorate the severity of copper deficiency in fructose-fed rats. Lipid peroxidation was measured in the livers and hearts of rats fed a copper-deficient diet (0.6 microg Cu/g) containing 62% fructose with adequate vitamin E (0.1 g/kg diet) or supplemented with vitamin E (1.0 g/kg diet). Hepatic lipid peroxidation was significantly reduced by vitamin E supplementation compared with the unsupplemented adequate rats. In contrast, myocardial lipid peroxidation was unaffected by the level of vitamin E. Regardless of vitamin E supplementation, all copper-deficient rats exhibited severe signs of copper deficiency, and some of the vitamin E-supplemented rats died of this deficiency. These findings suggest that although vitamin E provided protection against peroxidation in the liver, it did not protect the animals against the severity of copper deficiency induced by fructose consumption.  相似文献   

15.
An 8-week feeding trial was conducted to determine the dietary copper (Cu) requirement and its effect on the non-specific immune responses of juvenile grass shrimp, Penaeus monodon. Purified diets with seven levels (0, 10, 20, 30, 40, 80, 160 mg Cu kg diet(-1) of supplemental Cu were fed to P. monodon (mean initial weight 0.29 +/- 0.004 g). Each diet was fed to three replicate groups of shrimp. The rearing water contained 1.53 microg Cu 1(-1). Shrimp fed diets supplemented with 10 and 20 mg Cu kg diet(-1) had significantly (P < 0.01) greater weight gain, feed efficiency (FE) and protein efficiency ratio (PER) than those fed the unsupplemented control diet and diets supplemented with > or = 40 mg Cu kg diet(-1). Whole body Cu concentration in shrimp generally increased as dietary Cu supplementation increased. Total haemocyte count (THC) was higher in shrimp fed diets supplemented with 10-30 mg Cu kg diet(-1) than shrimp fed the unsupplemented control diet and diets supplemented with > or = 40 mg Cu kg diet(-1). Intracellular superoxide anion (O2-) production ratios were significantly higher in shrimp fed diets supplemented with 10-30 mg Cu kg diet(-1) than shrimp fed the diet supplemented with 160 mg Cu kg diet(-1). Analysis by polynomial regression of weight gain percent, FE and by linear regression of the whole-body Cu retention of shrimp indicated that the adequate dietary Cu concentration in growing P. monodon is about 15-21 mg Cu kg diet (-1). The immune indicators suggest that an adequate dietary Cu concentration for non-specific immune responses in P. monodon is about 10-30 mg Cu kg diet(-1).  相似文献   

16.
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 μg/g) or copper-adequate diet (CuA, 5.1 μg/g). After 35–41 d on their respective diets, rats from each group were placed inside a pressure vessel kept at 27°C under one of two pressure protcols. 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.  相似文献   

17.
Dietary copper deficiency has been shown to significantly reduce acetylcholine (Ach)-induced vascular smooth muscle relaxation. The current study was designed to examine the relative relationship between dietary copper and the vasodilator response to Ach in the microcirculation of the rat. Male weanling rats were fed a purified basal diet supplemented with 6.0, 3.0, 1.5 or 0.0 microg Cu/g diet for 4 weeks to provide an adequate, two marginal, and deficient intakes of dietary copper. Arteriole dilation in response to increasing concentrations of acetylcholine (10(-7) to 10(-4) M) was measured in the in vivo cremaster muscle microcirculation for each dietary group. Liver copper and both aortic and erythrocyte Cu,Zn-SOD activity were used as indices of systemic copper status. Dilation to the increasing concentrations of Ach was only different in the 0 microg Cu supplemented group compared to the copper-adequate control values. However, the combined results showed an exponential increase in 10(-5) M Ach-induced vasodilation as liver copper concentration increases from 0 microg Cu/g dry wt. This relationship suggests that dilation is attenuated at liver Cu concentrations below 5 microg/g dry wt. The results indicate that Ach-induced vasodilation is copper-dependent but that the pathway is not very sensitive to short-term marginal restriction of copper intake.  相似文献   

18.
Prostaglandin synthesis shows dependence on lipid hydroperoxides and resultant oxygen derived radical formation. In view of the importance of dietary copper in cytosolic copper dependent superoxide dismutase (Cu/Zn SOD) activity and the role of SOD in oxygen radical formation, the influence of dietary copper on prostacylin (PGI2) synthesis and SOD activity in rat aorta was examined. Copper deficient (0.5 micrograms Cu/g diet) rats showed a significant 47% reduction in PGI2 synthesis rates by aortic ring incubations in comparison to copper adequate (6.0 micrograms Cu/g diet) animals. Aortic SOD activity was reduced by 46% in copper deficiency in comparison to copper adequate animals. Marginal dietary copper (1.6 micrograms Cu/g diet) significantly reduced aortic SOD activity by 32% but was without effect on aortic ring incubation PGI2 synthesis. These results indicate that dietary copper deficiency, and the resultant decrease in SOD activity, depresses aortic PGI2 synthesis.  相似文献   

19.
Copper deficiency was induced in weanling rats fed diets whose sole source of carbohydrates was starch or fructose for 7 weeks. Conventional parameters of copper status, plasma copper concentrations, ceruloplasmin activity, and erythrocyte superoxide dismutase (SOD) activity were longitudinally monitored weekly to follow the development of the deficiency and to correlate these indices with the degree of severity of the deficiency. Although 30% of the rats fed a copper-deficient fructose diet died and no deaths occurred in rats fed the copper-deficient starch diet, plasma copper, ceruloplasmin, and SOD activities were reduced to a similar extent in all rats fed copper-deficient diets regardless of the type of dietary carbohydrate. Thus, none of the indices used accurately reflected the greater degree of deficiency or mortality in rats fed the fructose diet deficient in copper. The results of the present study underscore the need for more sensitive tests or alternative parameters to assess copper status in living animals.  相似文献   

20.
Experiments were conducted in copper deficient male and female rats fed diets containing fructose or starch in order to determine whether the same type of interaction between copper status and dietary carbohydrate found in male rats also occurs in the female rat. Mortality occurred only in the male rats fed the fructose diet deficient in copper with 40% of the animals dying during the 8 week study. Only anemia, hypercholesterolemia, increased BUN, heart hypertrophy and reduced body weight were observed in these animals which could be related to their mortality. Despite the increased mortality, plasma ceruloplasmin, erythrocyte SOD and hepatic copper concentrations were reduced to a similar extent in all rats regardless of the sex of the animals or of the type of dietary carbohydrate fed. The results of the present study indicate that although direct measurements of copper status of female rats fed fructose diet deficient in copper are similar to their male counterpart, they are apparently protected from the lethal consequences of the deficiency.  相似文献   

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