Increased Rat Brain Cytochrome C Correlates with Degree of Perinatal Copper Deficiency Rather than Apoptosis

Dietary Supplementation of L-Arginine and N-Carbamylglutamate Attenuated the Hepatic Inflammatory Response and Apoptosis in Suckling Lambs with Intrauterine Growth Retardation

L-arginine (Arg) is a semiessential amino acid with several physiological functions. N-Carbamylglutamate (NCG) can promote the synthesis of endogenous Arg in mammals. However, the roles of Arg or NCG on hepatic inflammation and apoptosis in suckling lambs suffering from intrauterine growth restriction (IUGR) are still unclear. The current work is aimed at examining the effects of dietary Arg and NCG on inflammatory and hepatocyte apoptosis in IUGR suckling lambs. On day 7 after birth, 48 newborn Hu lambs were selected from a cohort of 432 twin lambs. Normal-birthweight and IUGR Hu lambs were allocated randomly (n = 12/group) to control (CON), IUGR, IUGR+1% Arg, or IUGR+0.1% NCG groups. Lambs were fed for 21 days from 7 to 28 days old. Compared with CON lambs, relative protein 53 (P53), apoptosis antigen 1 (Fas), Bcl-2-associated X protein (Bax), caspase-3, cytochrome C, tumor necrosis factor alpha (TNF-α), nuclear factor kappa-B (NF-κB) p65, and NF-κB pp65 protein levels were higher (P < 0.05) in liver from IUGR lambs, whereas those in liver from IUGR lambs under Arg or NCG treatment were lower than those in IUGR lambs. These findings indicated that supplementing Arg or NCG reduced the contents of proinflammatory cytokines at the same time when the apoptosis-related pathway was being suppressed, thus suppressing the IUGR-induced apoptosis of hepatic cells.

Dietary N-carbamylglutamate and rumen-protected L-arginine supplementation during intrauterine growth restriction in undernourished ewes improve fetal thymus development and immune function

The aims of the present study were to determine whether dietary supplementation with N-carbamylglutamate (NCG) and rumen-protected l-arginine (RP-Arg) to underfed Hu sheep would improve fetal thymus development and immune function. From Day 35 to Day 110 of gestation, 32 Hu ewes carrying twin fetuses were randomly allocated to one of four groups (n=8 per group): 100% National Research Council (NRC)-recommended nutrient requirements (CON), 50% NRC recommendations (RES), 50% NRC recommendations supplemented with 20gday-1 RP-Arg (RES+ARG), and 50% NRC recommendations supplemented with 5gday-1 NCG (RES+NCG). Medullary thickness was increased (P<0.05) in RES compared with CON ewes, but was reduced (P<0.05) in both RES+ARG and RES+NCG ewes compared with RES ewes. There were no differences in superoxide dismutase and glutathione peroxidase activity or malondialdehyde levels in the RES+ARG and RES+NCG groups compared with the CON group (P>0.05). Concentrations of IgA, interleukin (IL)-1β and IL-10 in fetal umbilical cord blood were reduced (P<0.05) in RES compared with CON ewes, but were increased (P<0.05) in both RES+ARG and RES+NCG ewes. Expression of Bax, Fas and p53 mRNA was increased (P<0.05) in RES compared with CON ewes, but were reduced (P>0.05) in both RES+ARG and RES+NCG ewes. These results indicate that dietary supplementation with NCG and RP-Arg could help alleviate the negative effects of intrauterine growth restriction on fetal thymus development and immune function.

Analyses of apoptosis and DNA damage in bovine cumulus cells after in vitro maturation with different copper concentrations: consequences on early embryo development

The aim of this study was to investigate the influence of copper (Cu) during in vitro maturation (IVM) on apoptosis and DNA integrity of cumulus cells (CC); and oocyte viability. Also, the role of CC in the transport of Cu during IVM was evaluated on oocyte developmental capacity. Damage of DNA was higher in CC matured without Cu (0 µg/dl Cu, P < 0.01) with respect to cells treated with Cu for cumulus-oocyte complexes (COCs) exposed to 0, 20, 40, or 60 µg/dl Cu). The percentage of apoptotic cells was higher in CC matured without Cu than in CC matured with Cu. Cumulus expansion and viability of CC did not show differences in COC treated with 0, 20, 40, or 60 µg/dl Cu during IVM. After in vitro fertilization (IVF), cleavage rates were higher in COC and DO + CC (denuded oocytes + CC) with or without Cu than in DO. Independently of CC presence (COC, DO + CC or DO) the blastocyst rates were higher when 60 µg/dl Cu was added to IVM medium compared to medium alone. These results indicate that Cu supplementation to IVM medium: (i) decreased DNA damage and apoptosis in CC; (ii) did not modify oocyte viability and cumulus expansion; and (iii) improved subsequent embryo development up to blastocyst stage regardless of CC presence during IVM.

Effects of Intrauterine Growth Restriction During Late Pregnancy on the Development of the Ovine Fetal Thymus and the T-Lymphocyte Subpopulation

PROBLEM

The retarded development of fetal thymus in intrauterine growth restriction (IUGR) from maternal undernutrition during late pregnancy destroys the tridimensional structure and modifies the development of fetal T lymphocytes. The mechanisms, however, remain unclear. The objective of this study was to investigate the effect of IUGR during late pregnancy on the development of the ovine fetal thymus and the T-lymphocyte subpopulation.

METHOD OF STUDY

Eighteen time-mated ewes with singleton fetuses were allocated to three groups at day 90 of pregnancy: restricted group 1 (RG1, 0.18 MJ ME/BW(0.75) /day, n = 6), restricted group 2 (RG2, 0.33 MJ ME/BW(0.75) /day, n = 6) and a control group (CG, ad libitum, 0.67 MJ ME/BW(0.75) /day, n = 6). Fetuses were recovered at slaughter on day 140.

RESULTS

Fetuses in RG1 exhibited decreased (P < 0.05) thymic weight, cortical thickness, cortical:medullary, DNA content, total antioxidant capacity, and superoxide dismutase; intermediate changes were found in RG2 fetuses, including decreased thymic weight, cortical thickness, and DNA content (P < 0.05). The reductions (P < 0.05) of CD4(+) CD8(+) T cells, relative mRNA expression of keratin 8, recombination activating gene 1 (RAG1), and B-cell lymphoma 2 (Bcl-2) were found in both restricted groups. In addition, there was reduced mRNA expression (P < 0.05) of T-cell receptor, apoptosis antigen 1 ligand, and RAG2 in the RG1 group. In contrast, increases in glutathione peroxidase, malondialdehyde, caspase-3, Cytochrome c, and CD4(+) T cells were observed (P < 0.05), and higher mRNA expressions (P < 0.05) of protein 53, Bcl-2 associated X protein (Bax), and apoptosis antigen 1 (Fas) were found in RG1 fetuses; and thymuses of RG2 fetuses had increased caspase-3, and expression of Fas and Bax (P < 0.05), relative to control fetuses.

CONCLUSION

These results indicate that reduced cell proliferation, oxidative stress, and increased cell apoptosis were the potential mechanisms for impaired development and microenvironment of IUGR fetal thymus, and for modifying the maturation of CD4(+) CD8(+) thymocytes underlying their reduced numbers .

Mitochondrial complex enzyme activities and cytochrome C expression changes in multiple sclerosis

Blood platelets have been widely proposed as biomarkers in studies of mitochondrial function and aging-related and neurodegenerative diseases. Defects in mitochondrial function were found not only in the substantia nigra of Parkinson's disease patients but also in their blood platelets. Similarly, it has also been described in the blood platelet mitochondria of Alzheimer's disease patients. To study mitochondrial aerobic metabolism function and protein expression in platelets of multiple sclerosis (MS) patients and control subjects, mitochondrial aconitase, mitochondrial superoxide dismutases 1 and 2 (SOD1 and SOD2), and respiratory complex enzyme activities in platelets of MS patients and control subjects were determined. Likewise, mitochondrial lipid peroxidation and mitochondrial SOD1 and cytochrome c expressions were investigated. Mitochondrial aconitase activity was higher in MS patients than in controls (P < 0.05). A significant increase on all respiratory complex activities in MS patients was observed (P < 0.05). Mitochondrial lipid peroxidation was significantly higher in MS patients than in controls (P < 0.05). Significant changes of cytochrome c and mitochondrial SOD1 expressions were detected (P < 0.05), with a decrease of 44 ± 5 % and an increase of 46 ± 6 %, respectively. Our study reveals that significant changes in mitochondrial aerobic metabolism function and mitochondrial SOD1 and cytochrome c expressions are produced in platelets of MS patients.

Variable response of selected cuproproteins in rat choroid plexus and cerebellum following perinatal copper deficiency

Recent immunohistochemical characterization of the copper transport protein, Ctr1, reported enriched levels in mouse choroid plexus, and enhancement by copper deficiency. To extend and confirm this, experiments were conducted with Holtzman rats. Following perinatal copper deficiency there was an 80% reduction in brain copper of 24-27 day old copper-deficient (Cu-) rat pups compared to copper-adequate (Cu+) controls. Choroid plexus immunoblot analysis with rabbit anti-hCtr1 demonstrated a 50% higher Ctr1 protein expression in Cu-samples. However, levels of copper chaperone for superoxide dismutase (CCS) were unchanged, suggesting that Ctr1 buffers the choroid plexus against copper deficiency, since CCS normally is much higher in Cu-tissues. There were 13% lower levels of cytochrome c oxidase subunit IV (COX IV) detected in Cuchoroid plexus. In contrast, in cerebellum of Cu-rats CCS was 2-fold higher and COXIV 1.7-fold lower than Cu+ rats consistent with severe copper deficiency. Brain mitochondria from Cu-rats had severe reductions in COXIV content and CCO activity and modest but significant elevations in CCS and reductions in Cu, Zn-superoxide dismutase. COXIV may be a more sensitive marker for copper deficiency than CCS and may prove useful to assess copper status.

Perinatal copper deficiency alters rat cerebellar purkinje cell size and distribution

Copper is required for activity of several key enzymes and for optimal mammalian development, especially within the central nervous system. Copper-deficient (CuD) animals are visibly ataxic, and previous studies in rats have demonstrated impaired motor function through behavioral experiments consistent with altered cerebellar development. Perinatal copper deficiency was produced in Holtzman rat dams by restricting dietary copper during the last two thirds of gestation and lactation. Male offspring were evaluated at postnatal day 25. Compared to cerebella from copper-adequate pups, the CuD pups had larger Purkinje cell (PC) size and irregularities in the Purkinje cell monolayer. These results suggest that the ataxic behavioral phenotype of CuD rats may result from disrupted inhibitory pathways in the cerebellum. A similar PC phenotype is seen in Menkes disease and in mottled mouse mutants with genetic copper deficiency, suggesting that copper deficiency and not just specific loss of ATP7A function is responsible.

Influence of copper on early development: prenatal and postnatal considerations

Copper (Cu) is an essential nutrient whose requirement is increased during pregnancy and lactation. These represent times of critical growth and development, and the fetus and neonate are particularly vulnerable to deficiencies of this nutrient. Genetic mutations that predispose the offspring to inadequate stores of Cu can be life threatening as is observed in children with Menkes disease. During the last decade, severe Cu deficiency, once thought to be a rare condition, has been reported in the literature at an increasing frequency. Secondary Cu deficiencies can be induced by a variety of ways such as excessive zinc or iron intake, certain drugs, and bariatric surgery. Premature and low birth weight infants can be born with low Cu stores. A number of mechanisms can contribute to the teratogenicity of Cu including decreased activity of select cuproenzymes, increased oxidative stress, decreased nitric oxide availability, altered iron metabolism, abnormal extracellular matrix protein crosslinking, decreased angiogenesis and altered cell signaling among others. The brain, heart, and vessels as well as tissues such as lung, skin and hair, and systems including the skeletal, immune, and blood systems, are negatively affected by suboptimal Cu during development. Additionally, persistent structural, biochemical, and functional adverse effects in the offspring are noted even when Cu supplementation is initiated after birth, supporting the concept that adequate Cu nutriture during pregnancy and lactation is critical for normal development. Although Cu-containing IUDs are an effective method for increasing intrauterine Cu concentrations and for reducing the risk of pregnancy, high amounts of dietary Cu are not thought to represent a direct developmental risk.

Copper deficiency alters the neurochemical profile of developing rat brain

Copper deficiency is associated with impaired brain development and mitochondrial dysfunction. Perinatal copper deficiency was produced in Holtzman rats. In vivo proton NMR spectroscopy was used to quantify 18 cerebellar and hippocampal metabolites on postnatal day 21 (P21). Copper status was evaluated in male copper-adequate (CuA) and copper-deficient (CuD) brothers at P19 and at P23, 2 days following NMR experiments, by metal and in vitro metabolite data. Compared to CuA pups, CuD pups had lower ascorbate concentration in both brain regions, confirming prior HPLC data. Both regions of CuD rats also had lower N-acetylaspartate levels consistent with delayed development or impaired mitochondrial function similar to prior work demonstrating elevated lactate and citrate. For other metabolites, the P21 neurochemical profile of CuD rats was remarkably similar to CuA rats but uniquely different from iron-deficient or chronic hypoxia models. Further research is needed to determine the neurochemical consequences of copper deficiency.

Augmented cerebellar lactate in copper deficient rat pups originates from both blood and cerebellum

Copper (Cu) is essential for proper brain development, particularly the cerebellum, and functions as a cofactor for enzymes including mitochondrial cytochrome c oxidase (CCO). Cu deficiency severely limits CCO activity. Augmented lactate in brain of Cu deficient (Cu-) humans and cerebella of Cu- rats is though to originate from impaired mitochondria. However, brain lactate may also originate from elevated blood lactate. The hypothesis that cerebellar lactate originates from elevated blood lactate in Cu- rat pups was tested. Analysis of Cu- and Cu adequate (Cu+) rat pups (experiment I) revealed blood lactate was elevated in Cu- rat pups and cerebellar lactate levels were closely correlated to blood lactate concentration. A second rat experiment (experiment II) assessed Cu- cerebellar lactate without the confounding factor of elevated blood lactate. Blood lactate levels of Cu- rat pups in experiment II were equal to those of controls; however, Cu- cerebellar lactate was still elevated, suggesting mitochondrial impairment by Cu deficiency. Treatment of rat pups with dichloroacetate (DCA), an activator of mitochondrial pyruvate dehydrogenase complex (PDC), lowered Cu- cerebellar lactate to control levels suggesting PDC inhibition is a site of mitochondrial impairment in Cu- cerebella. Results suggest Cu- cerebellar lactate originates from blood and cerebellum.

Fructose-2,6-bisphosphate is lower in copper deficient rat cerebellum despite higher content of phosphorylated AMP-activated protein kinase

Limitation in copper (Cu) leads to pathophysiology in developing brain. Cu deficiency impairs brain mitochondria and results in high brain lactate suggesting augmented anaerobic glycolysis. AMP activated protein kinase (AMPK) is a cellular energy "master-switch" that is thought to augment glycolysis through phosphorylation and activation phosphofructokinase 2 (PFK2) resulting in increases of the glycolytic stimulator fructose-2,6-bisphosphate (F2,6BP). Previously, Cu deficiency has been shown to augment cerebellar AMPK activation. Cerebella of Cu-adequate (Cu+) and Cu-deficient (Cu-) rat pups were assessed to evaluate if AMPK activation in Cu- cerebella functioned to enhance PFK2 activation and increase F2,BP concentration. Higher levels of pAMPK were detected in Cu- cerebella. However, PFK2 activity, mRNA, and protein abundance were not affected by Cu deficiency. Surprisingly, F2,6BP levels were markedly lower in Cu- cerebella. Lower F2,6BP may be due to inhibition of PFK2 by citrate, as citrate concentration was significantly higher in Cu- cerebella. Data suggest AMPK activation in Cu- cerebellum does not augment glycolysis through a PFK2 mechanism. Furthermore, other metabolite data suggest that glycolysis may actually be blunted, since levels of glucose and glucose-6-phosphate were higher in Cu- cerebella than controls.

Copper deficiency results in AMP-activated protein kinase activation and acetylCoA carboxylase phosphorylation in rat cerebellum

Copper (Cu) deficiency impairs cerebellar development including biosynthetic processes like myelination and synaptogenesis. The activity of cerebellar mitochondrial cuproenzyme cytochrome c oxidase is markedly lower in Cu deficient rat pups and is accompanied by higher lactate levels indicating mitochondrial inhibition. Cu deficiency impaired energy metabolism is thought to contribute to developmental delays, but specific mechanisms linking these phenomena have remained unexplored. AMP-activated protein kinase (AMPK) is a cellular energy sensor that is activated during mitochondrial inhibition and shuts down biosynthetic processes to help conserve cellular ATP levels. Activated AMPK phosphorylates and inhibits acetylCoA carboxylase (ACC), the first enzyme in fatty acid biosynthesis. We hypothesize that AMPK is activated and ACC inhibited in Cu deficient cerebella. Perinatal copper deficiency was studied in young rats in rapidly frozen cerebella. Compared to copper-adequate (Cu+) pups, copper-deficient (Cu-) pups were hypothermic, had lower brain copper levels and markedly higher cerebellar lactate. Concentration of phosphorylated AMPK (pAMPK), indicating AMPK activation, was robustly higher in Cu- cerebella of rat pups at two ages and in two separate experiments. Compared to Cu+ cerebella, pACC content was significantly higher in all Cu- samples. Mechanisms leading to AMPK activation remain elusive. Higher AMP/ATP ratios and increased reactive nitrogen species (RNS) can lead to AMPK activation. ATP and AMP concentrations were unaltered and nitric oxide metabolites and 3-nitrotyrosine peptide levels remained unchanged in Cu- cerebella. AMPK activation may explain how ATP levels can be maintained even with a severe mitochondrial loss of CCO function.

Copper deficiency elicits glial and neuronal response typical of neurodegenerative disorders

Dysregulation of copper homeostasis has been associated with neurodegenerative diseases including Alzheimer's disease, amyotrophic lateral sclerosis (ALS) and prion diseases. The investigation of the role of abnormal copper level in the development of neuropathological damage is essential for the understanding of pathogenetic mechanisms of these neurodegenerative disorders. Using a mouse model of perinatally induced copper deficiency, the present study analysed the response of neuronal and glial cells to copper deficiency from infancy to young adult age. In mice born and maintained after weaning on copper-deficient diet, copper measurements indicated that at 6-8 weeks the copper levels in the brain were decreased by about 80% with respect to controls. In the brain of copper-deficient mice, microglial and astrocytic activation was observed, mostly in the cerebral cortex and thalamus. In addition, small vacuolated globoid cells confined to the subgranular zone of the dentate gyrus were found in the third postnatal week, and larger vacuolar profiles, identified as neuronal vacuoles, were observed in layer V of the cortex after the fourth week. The spatial distribution and temporal onset of vacuolation appeared to be unrelated to those of activated microglia and astrocytes. Nitrotyrosine-positivity was found to reflect the distribution of vacuoles in the cortex. The specific histopathological features here reported, as well as the severity of neurological deficits observed in this murine model of copper deficiency, strongly suggest that some hallmarks of neurodegenerative disorders could be mediated by multifactorial pathogenetic mechanisms that include copper dysregulation.