Lipid-soluble Vitamins Research Articles

Roles of lipid-soluble vitamins during ontogeny of marine fish larvae

The roles of lipid-soluble vitamins during ontogeny of marine fish larvae are a subject topic where only fragments of the whole picture are known. Most of the research has been focussed on the larval requirements and the availability of these vitamins in the live feed organisms used for early-stage larvae, while the function of the vitamins in the larvae themselves is largely unknown. Our knowledge is mostly extrapolated from research on other vertebrates and also in part from juvenile and adult fish. Vitamin A is known to be essential for establishing body and organ axes in vertebrate embryos and interacts with other nutrients such as vitamin D and fatty acids through the steroid/thyroid nuclear hormone receptor family. In marine fish larvae, excess vitamin A stimulates pigmentation, but at the same time induces vertebral deformities. Live feed organisms contain very little vitamin A but marine fish larvae appear to convert carotenoids in Artemia and copepods to vitamin A, while rotifers, which contain little carotenoids, should be enriched with vitamin A. Vitamin E acts as an antioxidant and is important for the protection of marine fish larvae against the oxidation pressure probably present in intensive rearing systems. Vitamin E may also have other roles connected to its modulation of cell and tissue red-ox balance. In marine fish larvae and juveniles, vitamin E has been shown to enhance the symptoms of vitamin C deficiency, while protecting against the oxidative effect of n-3 fatty acids. Vitamin D is important for the modulation of calcium and phosphorus homeostasis and for the development of the vertebrate skeleton. Vitamin K influences bone development and coagulation of the blood. There is little information on vitamins D and K connected to the ontogeny of marine fish larvae.

Engineering tocopherol biosynthetic pathway in Arabidopsis leaves and its effect on antioxidant metabolism

With genetic manipulation, five genes ( HPPD, VTE2, VTE3, VTE1, and VTE4), which encode enzymes involved in tocopherol biosynthesis, were over-expressed in model plant Arabidopsis thaliana, either alone or in couple combinations ( VTE2 + VTE4 and VTE3 + VTE4), to value and compare the roles of enzymes played in tocopherol biosynthetic pathway under the same genetic background. Our results suggested that, elevated expression level of biosynthetic pathway gene affected either total tocopherol content or composition, it is recommended to choose two or more enzymes with different functions for genetic manipulation. It was also found that metabolic engineering of tocopherol biosynthetic pathway affected endogenous ascorbate and glutathione pools in leaves. Further study suggested that expression levels of genes encoding enzymes of Halliwell–Asada cycle were up-regulated, such as APX, DHAR and MDAR. These findings provide hints on the relationship of lipid-soluble antioxidant vitamin E and water-soluble antioxidants vitamin C and glutathione, which will help to perfect theory in plant physiology and give practical instruction for metabolic engineering.

Birth weight was negatively correlated with plasma ghrelin, insulin resistance, and coenzyme Q10 levels in overweight children

The purpose of this study was to investigate the relationship between birth weight and appetite related hormones, insulin resistance, and antioxidant status in overweight children aged 9-10 years. Thirty-four healthy overweight children (18 boys, 16 girls) were evaluated with respect to anthropometric measurement, lipid profiles, leptin, ghrelin, glucose, insulin, C-peptide, lipid soluble vitamins, and antioxidant enzyme activities. I found that birth weight was negatively correlated with insulin resistance parameters, ghrelin, and coenzyme Q10 levels. There was a significant positive correlation between present BMI and leptin level, while a negative correlation was noted between the BMI and α-tocopherol and lycopene levels. When total subjects were classified into three groups by tertiles of birth weight, the lowest tertile of birth weight (LTB) group showed higher levels of fasting glucose, HOMA-IR, and ghrelin level than the highest tertile of birth weight (HTB) groups. On the other hand, HTB group showed an increased oxidative stress (decreased coenzyme Q10 level and catalase activity) compared to the LTB group. In conclusion, plasma ghrelin level might play an important role in accelerated growth in overweight children with LTB. Increased insulin resistance is present in overweight children with LTB, while decreased coenzyme Q10 and catalase activity in overweight children with HTB. These results suggest that birth weight might be an important factor for determination of treatment for obesity related complications in childhood obesity.

Lipid-soluble vitamin C (ascorbate 6-palmitate) Does Not Protect Paraoxonase from Hypochlorite

Lipid-soluble vitamin C (ascorbate 6-palmitate) Does Not Protect Paraoxonase from Hypochlorite

Aluminum concentration in serum of children on long-term parenteral nutrition and in parenteral nutrition solution components

summary Background & Aims: Aluminum is a contaminant of parenteral nutrition solutions. Children who receive long-term parenteral nutrition are at risk of aluminum overload in tissues and its toxic effect. The aim of this study was to assess the incidence of aluminum overloading in those children and the level of aluminum contamination in parenteral nutrition solutions. Methods: A furnace atomic absorption was used to assess serum aluminum concentration in 24 patients, aged 2–20 years. These patients had received parenteral nutrition therapy ranging from 2 years to 14.7 years. Aluminum concentrations were also determined in parenteral nutrition solution components. Results: We found increased amount of aluminum concentration in calcium gluconate (6000 mg/l), in trace element (Addamel :7 00mg/l), amino acid solution (10% Primene :6 0mg/l), lipid-soluble vitamins (Vitalipid :5 00mg/l), and lipids emulsions (20%ClinOleic :1 10mg/l, Lipofundin MCT/LCT :5 5mg/l). Aluminum intake from parenteral nutrition was 5.81–29.64 mg/kg/day, a dose exceeding the safety limit of 5 mg/kg/day. We found increased aluminum concentration (>20 mg/l) in serum of 10 patients; 7

P53 Peripheral neuropathy in systemic sclerosis: a clinical and electrophysiological correlation

Identification of the genes responsible for adult-onset type II citrullinemia (CTLN2) and citrin protein function have enhanced our understanding of citrin deficiency. Citrin deficiency is characterized by 1) neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD); 2) adaptation/compensation stage with unique food preference from childhood to adulthood; and 3) CTLN2. The treatment of NICCD aims to prevent the progression of cholestasis, and it includes medium chain triglycerides (MCT) milk and lactose-free milk, in addition to medications (e.g., vitamin K2, lipid-soluble vitamins and ursodeoxycholic acid). Spontaneous remission around the age of one is common in NICCD, though prolonged cholestasis can lead to irreversible liver failure and may require liver transplantation. The adaptation/compensation stage (after one year of age) is characterized by the various signs and symptoms such as hypoglycemia, fatty liver, easy fatigability, weight loss, and neuropsychiatric symptoms. Some poorly-controlled patients show failure to thrive and dyslipidemia caused by citrin deficiency (FTTDCD). Diet therapy is the key in the adaptation/compensation stage. Protein- and fat-rich diet with a protein: fat: carbohydrate ratio being 15–25%: 40–50%: 30–40% along with the appropriate energy intake is recommended. The use of MCT oil and sodium pyruvate is also effective. The toxicity of carbohydrate is well known in the progression to CTLN2 if the consumption is over a long term or intense. Alcohol can also trigger CTLN2. Continuous intravenous hyperalimentation with high glucose concentration needs to be avoided. Administration of Glyceol® (an osmotic agent containing glycerol and fructose) is contraindicated. Because the intense treatment such as liver transplantation may become necessary to cure CTLN2, the effective preventative treatment during the adaptation/compensation stage is very important. At present, there is no report of a case with patients reported having the onset of CTLN2 who are on the diet therapy and under the appropriate medical support during the adaptation/compensation stage.

Oxidation of Endobiotics Mediated by Xenobiotic-Metabolizing Forms of Human Cytochrome P450

Cytochrome P450s (P450 or CYPs) comprise a superfamily of enzymes that catalyze the oxidation of a wide variety of xenobiotic chemicals including drugs and environmental carcinogens. Recent studies have demonstrated that endogenous chemicals are also oxidized by human P450s which mainly metabolize xenobiotics. In this review, we summarize the expected physiological significance of the biotransfornation as well as Michaelis-Menten constants (Km), maximal velocities (Vmax), Vmax/Km (intrinsic clearance) values, and/or metabolic activities for 33 endogenous substrates, including (1) arachidonic acid and fatty acids, (2) steroid hormones, such as testosterone, progesterone, and allopregnanolone, (3) amines, such as tyramine, and (4) lipid-soluble vitamins, such as retinol and vitamin D3 analogues, mediated human P450 isoforms consisting of so-called drug-metabolizing enzymes for the purpose of predicting the key enzyme(s) in vivo. Arachidonic acid is metabolized via the epoxidation and omega-hydroxylation to many biologically active eicosanoids such as epoxyeicosatrienoic acids and hydroxyeicosatetraenoic acids by multiple P450 isoforms including CYP2C, CYP2E1 and CYP4A11. CYP2D in the brain may be involved in the metabolism of neuronal amines and steroids and in the regulation of the central nervous system. CYP1A2 and CYP3A4 appear to be the major P450 enzymes catalyzing the oxidation of all-trans-retinol to all-trans-retinoic acid in human liver, and CYP3A4 is one of the vitamin D3 25-hydroxylases. Although the significance of the contribution is still unknown in detail, the collective findings provide fundamental and useful information for the biological contribution of the metabolism of endogenous substances by drug-metabolizing enzymes, P450s. In addition, genetic polymorphism of these drug-metabolizing P450s may affect the metabolism of the endobiotics. Forthermore, these findings imply that xenobiotic oxidations by P450 enzymes are affected by endobiotic molecules and that the endobiotic-xenobiotic interactions as well as drug-drug interactions or drug-food/beverage interactions may be of great importance when understanding the basis for pharmacological and toxicological actions of a number of xenobiotic chemicals.

Free radical activity and lipid soluble antioxidant vitamin status in patients with long‐term ileal pouch‐anal anastomosis

OBJECTIVE: Ileal pouch-anal anastomosis (IPAA) is the operation of choice for patients with ulcerative colitis. Free radical activity and the status of lipid soluble antioxidant vitamins have not been previously assessed in patients with IPAA. The aim of the present study was to measure the plasma concentrations of lipophyllic antioxidants and free radical activity in IPAA patients and compare them with normal subjects. METHOD: Forty-eight IPAA patients and 50 healthy controls were studied. A dietary assessment of vitamin E (alpha-tocopherol) and carotene was undertaken and plasma antioxidant status was assessed. Plasma malondialdehyde (MDA) was measured to assess the extent of free radical damage. In IPAA patients, association between the degree of inflammation in the pouch mucosa and the plasma concentration of lipophyllic antioxidants and extent of free radical activity was investigated. RESULTS: The dietary intake of carotene was similar in both groups. Intake of vitamin E was significantly lower in patients than controls (P = 0.01). In the IPAA group plasma concentrations of alpha-carotene, beta-carotene and lycopene were significantly lower (P < 0.001) and alpha-tocopherol:cholesterol ratio significantly higher (P < 0.001). Free radical damage was significantly greater in patients than controls (P < 0.01). There were no significant correlations between the degree of inflammation in the pouch and plasma concentrations of MDA, carotenoids, alpha-tocopherol:cholesterol ratio or intake of vitamins. CONCLUSION: Compared with normal subjects, patients with IPAA have significantly lower plasma concentrations of lipophyllic antioxidants alpha-carotene, beta-carotene and lycopene and higher free radical activity suggesting increased oxidative stress. These differences do not appear to be related to diet and do not correlate with histological severity of pouch inflammation.

Alpha‐tocopherol transport in the lung is affected by the apoE genotype—Studies in transgenic apoE3 and apoE4 mice

Apolipoprotein E (apoE) is a major constituent of lipoproteins mediating peripheral uptake of lipids including the lipid-soluble vitamin alpha-tocopherol (alpha-toc). In a recent study, we observed significant lower alpha-toc concentrations in the lung of apoE4 compared with apoE3 transgenic mice. In this study, we determined the mRNA levels of genes encoding for proteins centrally involved in the uptake, export, and degradation of vitamin E. Receptors of alpha-toc uptake including scavenger receptor B1 (SR-B1), LDL receptor (LDLrec), and LDLrec-related protein 1 (LRP1) were lower in apoE4 when compared with apoE3 mice with statistical significance for SR-B1 and LRP1. Lung mRNA levels of the ATP-binding cassette A1 and the multidrug resistance transporter 1, surfactant proteins mediating the export of alpha-toc, were lower in apoE4 than in apoE3 mice. In addition, the mRNA levels of cytochrome P450 3A, a microsomal enzyme family involved in the degradation of alpha-toc, tended to be higher in the apoE4 when compared with the apoE3 genotype. Current data indicate that genes encoding for proteins involved in peripheral alpha-toc transport and degradation are affected by the apoE genotype probably accounting for thelower alpha-toc tissue concentration as observed in apoE4 mice.

Hypervitaminosis A altering the lipid profile in a hypercholesterolemic patient

Vitamin A is an essential lipid soluble vitamin needed for various cellular processes in humans. Erratic and supraphysiologic intake of vitamin A can lead to adverse effects that can be life threatening. For this reason, various medical societies have limited the recommended daily allowances and intakes (RDA and RDI, respectively) in an attempt to prevent hypervitaminosis toxicity. Studies have reported an association between hypertriglyceridemia and hypervitaminosis A. We present a patient with a history of familial combined hypercholesterolemia who developed an abrupt increase in his total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides (TG) after taking high doses of vitamin A supplements.

Exocrine Pancreatic Insufficiency, Dyserythropoeitic Anemia, and Calvarial Hyperostosis Are Caused by a Mutation in the COX4I2 Gene

Steatorrhea and malabsorption of lipid-soluble vitamins due to exocrine pancreatic insufficiency are common in patients with cystic fibrosis and are predominant in Shwachman-Bodian-Diamond, Pearson, and Johanson-Blizzard syndromes. In four patients who suffered from congenital exocrine pancreatic insufficiency, dyserythropoeitic anemia, and calvarial hyperostosis, we excluded these disorders and identified, by using homozygosity mapping, a mutation in the COX4I2 gene. The COX4 protein is an essential structural subunit of cytochrome c oxidase complex and has two isoforms, encoded by two different genes. We show that the ratio of COX4I2 to COX4I1 mRNA is relatively high in human acinar cells. The mutation is associated with marked reduction of COX4I2 expression and with striking attenuation of the physiologic COX4I2 response to hypoxia. Mutation analysis of COX4I2 is warranted in patients with malabsorption due to exocrine pancreatic insufficiency and in patients with dyserythropoeitic anemia.

Common Variation in the β-Carotene 15,15′-Monooxygenase 1 Gene Affects Circulating Levels of Carotenoids: A Genome-wide Association Study

Low plasma levels of carotenoids and tocopherols are associated with increased risk of chronic disease and disability. Because dietary intake of these lipid-soluble antioxidant vitamins is only poorly correlated with plasma levels, we hypothesized that circulating carotenoids (vitamin A-related compounds) and tocopherols (vitamin E-related compounds) are affected by common genetic variation. By conducting a genome-wide association study in a sample of Italians (n = 1190), we identified novel common variants associated with circulating carotenoid levels and known lipid variants associated with alpha-tocopherol levels. Effects were replicated in the Women's Health and Aging Study (n = 615) and in the alpha-Tocopherol, beta-Carotene Cancer Prevention (ATBC) study (n = 2136). In meta-analyses including all three studies, the G allele at rs6564851, near the beta-carotene 15,15'-monooxygenase 1 (BCMO1) gene, was associated with higher beta-carotene (p = 1.6 x 10(-24)) and alpha-carotene (p = 0.0001) levels and lower lycopene (0.003), zeaxanthin (p = 1.3 x 10(-5)), and lutein (p = 7.3 x 10(-15)) levels, with effect sizes ranging from 0.10-0.28 SDs per allele. Interestingly, this genetic variant had no significant effect on plasma retinol (p > 0.05). The SNP rs12272004, in linkage disequilibrium with the S19W variant in the APOA5 gene, was associated with alpha-tocopherol (meta-analysis p = 7.8 x 10(-10)) levels, and this association was substantially weaker when we adjusted for triglyceride levels (p = 0.002). Our findings might shed light on the controversial relationship between lipid-soluble anti-oxidant nutrients and human health.

Vitamin D and periodontal disease

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3); 1,25-dihydroxycholecalciferol or calcitriol] is the active form of vitamin D(3), a lipid-soluble vitamin that plays a role in calcium and bone metabolism. Recently, vitamin D(3) has been shown to function in cancer prevention, immunity and cardiovascular regulation. 1,25(OH)(2)D(3) exhibits physiological and pharmacological effects by activating the vitamin D receptor (VDR), a transcription factor of the nuclear receptor superfamily. 1,25(OH)(2)D(3) plays a role in maintaining oral health through its effects on bone and mineral metabolism and innate immunity, and several VDR gene polymorphisms have been reported to be associated with periodontal disease. VDR ligands should prove to be useful in the treatment and prevention of periodontal disease.

Hypovitaminosis D: a new risk marker for cardiovascular disease.

1. Joseph P. McConnell, PhD[⇑][1] 1. is director, Cardiovascular Laboratory Medicine, The Mayo Clinic and Foundation, Rochester, MN 2. Kevin F. Foley, PhD, MT 1. is a clinical chemist, Kaiser Permanente NW Laboratories, Portland, OR 3. Gina M. Vargas, PhD 1. is director, Importadora y Laboratorio Clinico ATM SRL: Cochabamba, Bolivia 1. Address for Correspondence: Joseph P. McConnell PhD, Mayo Clinic; Cardiovascular Laboratory Medicine, Rochester, Minnesota, (507) 284-0524, Fax: (507) 266-2888, Email: mcconnell.joseph{at}mayo.edu 1. Differentiate and define the various forms of vitamin-D, including Vitamin D2, D3 25(OH)D and 1,25(OH2)D. 2. Describe current opinion concerning vitamin-D dosing recommendations as well as issues around establishing a normal reference range. 3. Identify several diseases and pathologies for which hypovitaminosis D has been implicated. 4. Explain the correlations between serum 25(OH)D levels and the cardiovascular risk factors of hypertension and metabolic syndrome. 5. Describe the overall relationship between hypovitaminosis D and cardiovascular disease and the need for future studies to demonstrate causality. INTRODUCTION Vitamin D has a well-established role in calcium and phosphorus metabolism and bone mineralization. Vitamin D deficiency causes rickets in children, and in adults can lead to osteomalacia, resulting in muscle and bone weakness. Data are emerging that link hypovitaminosis D, as assessed by measurement of 25-hydroxyvitamin D [25(OH)D], with cardiovascular pathology. Vitamin D deficiency has been associated with hypertension, some inflammatory markers, and metabolic syndrome. More recently, low serum 25(OH)D has been associated with increased incidence of cardiovascular events and all-cause mortality. In this review, we discuss the role of vitamin D in health, and describe recent evidence linking hypovitaminosis D to cardiovascular disease. We describe controversies surrounding recommended daily intake and optimal serum levels, as well as discuss the need for further research relating vitamin D deficiency with cardiovascular disease. Vitamin D deficiency Vitamin D, which has also been referred to as the “sunshine vitamin” is a lipid-soluble vitamin obtained from both exogenous and endogenous sources. Some foods, such as eggs, fatty fish, and liver naturally contain vitamin D, but other dietary sources of vitamin D are from fortified foods, like milk and cereals, or from nutritional supplements1. Most of the body's vitamin D is produced endogenously following exposure of skin to sunlight, thus geography, season, skin tone, and sun exposure are primary predictors of vitamin D nutritional status2. Vitamin D obtained from sun is in the form of vitamin D3 (cholecalciferol), while vitamin D2 (ergocalciferol) or D3 may be obtained from dietary sources. Vitamin D2 differs… 1. Differentiate and define the various forms of vitamin-D, including Vitamin D2, D3 25(OH)D and 1,25(OH2)D. 2. Describe current opinion concerning vitamin-D dosing recommendations as well as issues around establishing a normal reference range. 3. Identify several diseases and pathologies for which hypovitaminosis D has been implicated. 4. Explain the correlations between serum 25(OH)D levels and the cardiovascular risk factors of hypertension and metabolic syndrome. 5. Describe the overall relationship between hypovitaminosis D and cardiovascular disease and the need for future studies to demonstrate causality. [1]: #corresp-1

Free radical activity and lipid soluble anti‐oxidant vitamin status in patients with long‐term ileal pouch‐anal anastomosis

Ileal pouch-anal anastomosis (IPAA) is the operation of choice for patients with ulcerative colitis. Free radical activity and the status of lipid soluble antioxidant vitamins have not been previously assessed in patients with IPAA. The aim of the present study was to measure the plasma concentrations of lipophyllic antioxidants and free radical activity in IPAA patients and compare them with normal subjects. Forty-eight IPAA patients and 50 healthy controls were studied. A dietary assessment of vitamin E (alpha-tocopherol) and carotene was undertaken and plasma antioxidant status was assessed. Plasma malondialdehyde (MDA) was measured to assess the extent of free radical damage. In IPAA patients, association between the degree of inflammation in the pouch mucosa and the plasma concentration of lipophyllic antioxidants and extent of free radical activity was investigated. The dietary intake of carotene was similar in both groups. Intake of vitamin E was significantly lower in patients than controls (P = 0.01). In the IPAA group plasma concentrations of alpha-carotene, beta-carotene and lycopene were significantly lower (P < 0.001) and alpha-tocopherol:cholesterol ratio significantly higher (P < 0.001). Free radical damage was significantly greater in patients than controls (P < 0.01). There were no significant correlations between the degree of inflammation in the pouch and plasma concentrations of MDA, carotenoids, alpha-tocopherol:cholesterol ratio or intake of vitamins. Compared with normal subjects, patients with IPAA have significantly lower plasma concentrations of lipophyllic antioxidants alpha-carotene, beta-carotene and lycopene and higher free radical activity suggesting increased oxidative stress. These differences do not appear to be related to diet and do not correlate with histological severity of pouch inflammation.

Developmental and pathological lymphangiogenesis: from models to human disease

The lymphatic vascular system, the body's second vascular system present in vertebrates, has emerged in recent years as a crucial player in normal and pathological processes. It participates in the maintenance of normal tissue fluid balance, the immune functions of cellular and antigen trafficking and absorption of fatty acids and lipid-soluble vitamins in the gut. Recent scientific discoveries have highlighted the role of lymphatic system in a number of pathologic conditions, including lymphedema, inflammatory diseases, and tumor metastasis. Development of genetically modified animal models, identification of lymphatic endothelial specific markers and regulators coupled with technological advances such as high-resolution imaging and genome-wide approaches have been instrumental in understanding the major steps controlling growth and remodeling of lymphatic vessels. This review highlights the recent insights and developments in the field of lymphatic vascular biology.

Vitamin antioxidants, lipid peroxidation, tumour stage, the systemic inflammatory response and survival in patients with colorectal cancer

Both the tumour growth and progression and the systemic inflammatory response have the potential to increase oxidative stress. We therefore examined the relationship between lipid-soluble antioxidant vitamins, lipid peroxidation, the systemic inflammatory response and survival in patients with primary operable (n = 53) and advanced inoperable (n = 53) colorectal cancer. Compared with those patients with primary operable colorectal cancer, patients with unresectable liver disease had significantly lower median concentrations of alpha-tocopherol (p < 0.001), lutein (p < 0.001), lycopene (p < 0.001), alpha-carotene (p < 0.01) and beta-carotene (p < 0.001) and higher malondialdehyde concentrations. An elevated systemic inflammatory response (Glasgow prognostic score, mGPS) was associated with a greater proportion of females (p < 0.05) and more advanced tumour stage (p < 0.05), lower circulating levels of retinol (p < 0.01), lutein (p < 0.01), lycopene (p < 0.01) and alpha- (p < 0.01) and beta-carotene but not MDA (p = 0.633). In the liver metastases group 41 patients died of their cancer and a further 1 patient died of intercurrent disease on follow-up. On univariate survival analysis, mGPS (p < 0.01), retinol (p < 0.001), alpha-tocopherol (p < 0.05) and alpha-carotene (p < 0.05) were associated significantly with cancer-specific survival. On multivariate survival analysis of these significant variables, only mGPS (p < 0.01) and retinol (p < 0.001) were independently associated with cancer-specific survival. The results of the present study showed that the systemic inflammatory response was associated with a reduction of lipid-soluble antioxidant vitamins, whereas advanced tumour stage was associated with increased lipid peroxidation in patients with colorectal cancer. Of the antioxidant vitamins measured, only retinol was independently associated with cancer-specific survival.

Basics in clinical nutrition: Lipid metabolism

Lipids are not only very important energy substrates but some fatty acids and lipid-soluble vitamins act as metabolic regulators. After ingestion of a mixed meal, fat is preferentially stored in adipose tissue whereas carbohydrates are oxidized. During fasting, fatty acids are released from adipose tissue and utilized as energy substrate in liver and extra hepatic tissue. This process is effectively controlled by catecholamines and insulin, which regulate hormone sensitive lipase and lipoprotein lipase. During a critical illness, increased adipose tissue lipolysis together with decreased fatty acid oxidation leads to increased triglyceride production and deposition in the liver (and in other tissues), with an augmented production of VLDL. This situation may contribute to the aggravation of organ dysfunction. In addition, several major changes are observed with respect to the concentration and composition of plasma cholesterol-rich lipoproteins. © 2008 European Society for Clinical Nutrition and Metabolism.

Oral Vitamin C Supplementation in Hemodialysis Patients and Its Effect on the Plasma Level of Oxidized Ascorbic Acid and Cu/Zn Superoxide Dismutase, an Oxidative Stress Marker

Background/Aim: Oxidative stress is known to be enhanced in hemodialysis patients, and one of its useful markers is plasma copper/zinc superoxide dismutase (Cu/Zn-SOD). The increase in plasma Cu/Zn-SOD can be inhibited by orally administered lipid-soluble vitamin E. We examined the antioxidative effects of water-soluble vitamin C administered orally on Cu/Zn-SOD levels in hemodialysis patients. Methods: Vitamin C was orally administered to 16 maintenance hemodialysis patients before each dialysis session. Doses were increased from 200 to 1,000 mg over 3 months. The levels of plasma vitamin C and Cu/Zn-SOD and its mRNA expression in leukocytes were determined 1, 2, and 3 months after the start of vitamin C administration. Furthermore, the levels of oxidized and reduced forms of plasma vitamin C were determined before the start of vitamin C administration and before and after dialysis at 1,000-mg vitamin C doses. Results: Following oral administration, the plasma levels of vitamin C and its oxidized form were increased. However, significant changes in plasma Cu/Zn-SOD or its mRNA expression in leukocytes were not observed. Conclusion: In maintenance hemodialysis patients, vitamin C administration resulted in a significant increase in the postdialysis level of the oxidized form of vitamin C, which suggested an increase in antioxidant effect. However, water-soluble vitamin C did not significantly suppress Cu/Zn-SOD expression enhancement.

Evaluation of Antioxidant Circulatory Lipid-Soluble Vitamins and Sodium as Non-invasive Indicators of Chronic Copper Exposure and Toxicity in Rainbow Trout, Oncorhynchus mykiss

Measurement of circulatory indicators of copper (Cu) exposure and toxicity in rainbow trout revealed elevated Cu concurrent with reduced sodium (Na) concentrations in plasma of Cu-exposed fish. Using a new normal phase high performance liquid chromatography (HPLC) method developed and validated for simultaneous extraction of lipid-soluble antioxidant vitamins we found that, contrary to our original hypothesis, plasma antioxidant status was enhanced as evidenced by a linear increase in vitamin E concentration. This suggests that vitamin E was mobilized from other metabolic pools to enhance circulatory antioxidant status possibly for delivery to Cu-sensitive locales. On the other hand, plasma vitamin A was not affected by the Cu exposure although its level decreased with time concurrent with an increase in fish size suggesting increased demand for growth. Thus circulatory Cu, Na, and vitamin E, but not vitamin A, can be used as non-lethal biomarkers of chronic Cu exposure and toxicity in fish.