Retinol binding protein expression is induced in HepG2 cells by zinc deficiency

The effects of cardiovascular and orthopaedic surgery on vitamin concentrations: a narrative review of the literature and mechanisms of action

Given the rise in worldwide chronic diseases, supplemented by an aging population, the volume of global major surgeries, encompassing cardiac and orthopedic procedures is anticipated to surge significantly. Surgical trauma can be accompanied by numerous postoperative complications and metabolic changes. The present review summarized the results from studies assessing the effects of orthopedic and cardiovascular surgery on vitamin concentrations, in addition to exploring the possible mechanisms associated with changes in concentrations. Studies have revealed a potentially severe depletion in plasma/serum concentrations of numerous vitamins following these surgeries acutely. Vitamins C, D and B1 appear particularly vulnerable to significant depletions, with vitamin C and D depletions consistently transpiring into inadequate and deficient concentrations, respectively. The possible multifactorial mechanisms impacting postoperative vitamin concentrations include changes in hemodilution and vitamin utilization, redistribution, circulatory transport and absorption. For a majority of vitamins, there has been a lack of investigation into the effects of both, cardiac and orthopedic surgery. Additionally, studies were predominantly restricted to short-term postoperative investigations, primarily performed within the first postoperative week of surgery. Overall, results indicated that further examination is necessary to determine the severity and clinical significance of the possible depletions in vitamin concentrations that ensue cardiovascular and orthopedic surgery.

Immunometabolic Status during the Peripartum Period Is Enhanced with Supplemental Zn, Mn, and Cu from Amino Acid Complexes and Co from Co Glucoheptonate

The peripartum (or transition) period is the most-critical phase in the productive life of lactating dairy cows and optimal supply of trace minerals through more bioavailable forms could minimize the negative effects associated with this phase. Twenty Holstein cows received a common prepartal diet and postpartal diet. Both diets were partially supplemented with an inorganic (INO) mix of Zn, Mn, and Cu to supply 35, 45, and 6 ppm, respectively, of the diet dry matter (DM). Cows were assigned to treatments in a randomized completed block design, receiving an daily oral bolus with INO or organic trace minerals (AAC) Zn, Mn, Cu, and Co to achieve 75, 65, 11, and 1 ppm supplemental, respectively, in the diet DM. Liver tissue and blood samples were collected throughout the experiment. The lower glutamic-oxaloacetic transaminase concentration after 15 days in milk in AAC cows indicate lower hepatic cell damage. The concentration of cholesterol and albumin increased, while IL-6 decreased over time in AAC cows compared with INO indicating a lower degree of inflammation and better liver function. Although the acute-phase protein ceruloplasmin tended to be lower in AAC cows and corresponded with the reduction in the inflammatory status, the tendency for greater serum amyloid A concentration in AAC indicated an inconsistent response on acute-phase proteins. Oxygen radical absorbance capacity increased over time in AAC cows. Furthermore, the concentrations of nitric oxide, nitrite, nitrate, and the ferric reducing ability of plasma decreased with AAC indicating a lower oxidative stress status. The expression of IL10 and ALB in liver tissue was greater overall in AAC cows reinforcing the anti-inflammatory response detected in plasma. The greater overall expression of PCK1 in AAC cows indicated a greater gluconeogenic capacity, and partly explained the greater milk production response over time. Overall, feeding organic trace minerals as complexed with amino acids during the transition period improved liver function and decreased inflammation and oxidative stress.

Gene expression profiles analysis of the growing rat liver in response to different zinc status by cDNA microarray analysis

The effects of zinc on growing rats were characterized using the dietary zinc-deficient (ZD) and Zinc-overdose (ZO) models. Zinc deficiency had negative effects on the host final body weight and liver zinc content, whereas zinc overdose had positive effects. In order to identify the molecular changes in the liver responding to dietary zinc status, cDNA microarrays were used to analyze the expression pattern of 9753 genes in the livers of rats fed ZD and ZO diet for 6 wk, compared with zinc-adequate ZA. The mRNA levels for 62 genes were affected significantly by the ZD diet, whereas 66 gene transcriptions were markedly changed in the ZO diet. Those predominant gene products involved in nitrogen metabolism (glutaminase), carbohydrate metabolism (aldolase), lipid metabolism (stearoyl-CoA desaturase), growth (insulin-like growth factor-binding protein), transcription and translation (zinc-finger protein), immune (natural-killer cell), signal transduction (mitogen- activated protein kinase), and ion transportation (ATPase Na+/K+ transporting peptide) were clustered. In conclusion, a number of mammalian genes related to zinc in the liver were identified. The characterization of the genes and their products will allow a more comprehensive analysis of the role of zinc in metabolism. Furthermore, the mRNA identified could be useful in establishing the mechanisms of zinc in the pleiotropic metabolisms in vivo.

Transcriptome and proteome analysis identifies the pathways that increase hepatic lipid accumulation in zinc-deficient rats

For identification of the underlying molecular changes in hepatic lipid metabolism in zinc deficiency, rats were force-fed a zinc-deficient diet. Subsequently DNA-microarray and proteome profiling was performed in combination with hepatic lipid analysis. Of 6200 target sequences analyzed, 268 transcripts showed altered expression levels in livers of zinc-deficient rats, with 43 genes thereof related to hepatic lipid metabolism. Northern blot analysis and quantitative real-time RT-PCR were employed to confirm changes in mRNA levels. Proteins involved in lipid metabolism were identified by proteome analysis. Functional gene clusters with uniform changes in transcript levels suggested that the pathways required for lipolysis and mitochondrial as well as peroxisomal fatty acid degradation were downregulated, whereas those needed for de novo fatty acid synthesis and triglyceride assembly were increased. Subsequent enzymatic analysis of liver tissues confirmed an almost 40% greater triacylglycerol concentration in zinc-depleted rats, as well as an altered fatty acid composition of the lipid fraction as determined by gas chromatography. Liver lipids of zinc-deficient rats had significantly greater proportions of cis-9-oleic acid, cis-11-vaccenic acid, caprylic acid, myristic acid, alpha-linolenic acid, and eicosapentaenoic acid, and significantly less stearic and arachidonic acids. These alterations in hepatic metabolism are discussed in the context of changes in mRNA and protein levels of enzymes and transporters responsible for fatty acid metabolism, sequestration, and their transcriptional control.

Ocular surface in Zn-deficient rats

PURPOSE

We studied the cornea and conjunctiva of Zn-deficient rats with an electron microscope and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to elucidate the role of trace elements in the cornea and conjunctiva.

MATERIALS AND METHODS

Twenty-one-day-old Wistar Kyoto rats were fed a Zn-deficient diet and deionized water for 7 weeks and then killed. The control rats were fed a Zn-deficient diet and deionized water supplemented with 3 mg Zn/100 ml. After 7 weeks on the deficient diet, another group of rats was given drinking water containing 3 mg Zn/100 ml and the usual diet containing 4.7 mg Zn/100 g for 8 weeks for recovery. The cornea and conjunctiva were examined by electron microscopy and TOF-SIMS.

RESULTS

Microvilli and microplicae in the most superficial layer of the epithelium of the Zn-deficient rat conjunctiva and cornea were prominently reduced, and dark cells were significantly increased. The numbers of goblet cells were decreased in the conjunctiva of the Zn-deficient group. Zn, Ca and Al ions were significantly fewer, but K, Fe, Cl and S ions were significantly more numerous in the Zn-deficient group than in the control group. In the cornea of the Zn-deficient group, there was significantly more Cl but less Ca and vitamin C than in the controls.

DISCUSSION

Zn deficiency may interfere with protein, nucleic acid and collagen synthesis through the reduction of Zn-containing enzymes. Myosin-like substance, actin filaments and tonofibrils are important structural components for microvilli and microplicae in the epithelium. Maldevelopment of these structural components may be related to disturbed activities of Zn-containing enzymes in protein and collagen synthesis because of Zn deficiency. In addition, Zn deficiency caused changes in the levels of Zn and other trace elements such as Ca, Al, S, Fe, and Cl and vitamin C.

CONCLUSION

Zn deficiency resulted in poorly developed microvilli and microplicae on the ocular surface tissues, reduced the number of goblet cells and changed the quantity of trace elements and vitamin C.

Changes in rat hepatic gene expression in response to zinc deficiency as assessed by DNA arrays

Zinc deficiency affects hepatic functions and due to the central role of the liver in metabolism, this may contribute to metabolic alterations in other tissues in zinc deficiency. In addition to clinical manifestations of zinc deficiency, we used cDNA- and oligonucleotide-arrays to compare the expression of > 2500 different genes in liver of rats force-fed a zinc-adequate or a zinc-deficient diet for 11 d. Radio- or fluorescence-labeled cDNAs from liver of control and zinc-deficient rats were hybridized to arrays. Approximately 1550 mRNAs were detected above background levels; by comparing expression profiles of the two groups, the mRNA levels of 66 genes were found to be altered by zinc deficiency. Steady-state expression levels of 35 genes were reduced, whereas the mRNA-levels of 31 genes were elevated. Array data were verified by Northern blot analysis for 24 selected genes and 19 were confirmed to be up- or down-regulated. Among those, predominantly gene products that participate in growth (i.e., insulin-like growth factor binding proteins), lipid metabolism (long-chain acyl-CoA synthetase), xenobiotic metabolism (cytochrome P(450) isoenzymes), the stress response (glutathione transferase), nitrogen metabolism (cytosolic aspartate aminotransferase), intracellular trafficking (syntaxin isoforms) and signal transduction (G-protein-coupled receptors) were identified. Additionally, regulation of mRNA levels of genes important for porphyrin synthesis and collagen metabolism was observed. In conclusion, we have identified in vivo a number of mammalian genes from different cellular pathways whose expression changes in response to zinc depletion. The characterization of the identified genes and their products will allow a more comprehensive analysis of the role of zinc in metabolism; moreover, the mRNAs identified could be useful in establishing biomarkers for the determination of zinc status in mammals.