Impact of elexacaftor/tezacaftor/ivacaftor on fat-soluble vitamin levels in children with cystic fibrosis

BACKGROUND

Children with cystic fibrosis are at risk of fat-soluble vitamin deficiency. CFTR modulators positively effect nutritional status. This study aimed to assess changes in serum vitamins A, D & E after starting ETI therapy to ensure levels were not abnormally high.

METHODS

Retrospective review of annual assessment data over 3½ years, before and after starting ETI in a specialist paediatric CF centre, including vitamin levels.

RESULTS

54 eligible patients were included, aged 5-15 yrs (median age 11.5). Median time to post measurements was 171 days. Median vitamin A was increased (1.38 to 1.63 µmol/L, p<0.001). Three patients (6%) had high vitamin A post-ETI, compared with none at baseline; and 2 (4%) had low levels compared to 4 (8%) at baseline. No changes in vitamins D&E.

CONCLUSIONS

This study found increased vitamin A, sometimes to high levels. We recommend testing levels within 3 months of starting ETI.

Age-dependent changes in fat- and water-soluble vitamins—National Health and Nutrition Examination Surveys study

Aging is an independent risk factor for the development of various diseases associated, among others, with detrimental blood levels of fat- and water-soluble vitamins. Thus, the objective of this study is to investigate age-related changes in blood levels of vitamin A, B12, C, D, and E. Subject serum vitamin levels were obtained from the combined National Health and Nutrition Examination Surveys (NHANES). NHANESIII and NHANES 1999–2000, 2001–2002, 2003–2004, and 2005–2006. The raw data set was stratified into five age groups G1- G5: 20 ≤ G1 < 30, 30 ≤ G2 < 40, 40 ≤ G3 < 50, 50 ≤ G4 < 60, and 60 ≤ G5 < 70 years of age. Age stratified data was cleaned using the modified Horn algorithm. The reference range for the vitamin level of a specific age group was defined as data between the first and third quartile of the subject defined by normal blood pressure and normal bone density. Age-dependent changes in serum/plasma vitamin levels were assessed using the bootstrap technique with 10,000 repeats and Bonferroni adjustment. There was a continuous increase in vitamin A, B12, D, and E levels in the blood. However, the vitamin C concentration remained virtually constant in all age groups. There was a lack of cross-correlations between lipid and water-soluble vitamin levels and blood pressure and bone health. The following reference levels for vitamin A, B12, C, D, and E in subjects older than 20 years of age were established: vitamin A: 1.32–2.8 mmol/L, vitamin B12: 257.94–498.33 pmol/L, vitamin C: 38.18–79.2 mmol/L, vitamin D: 76.33–199.36 nmol/L and vitamin E: 3.65–41.12 μmol/L.

Prediction of chronological and biological age from laboratory data

Aging has pronounced effects on blood laboratory biomarkers used in the clinic. Prior studies have largely investigated one biomarker or population at a time, limiting a comprehensive view of biomarker variation and aging across different populations. Here we develop a supervised machine learning approach to study aging using 356 blood biomarkers measured in 67,563 individuals across diverse populations. Our model predicts age with a mean absolute error (MAE), or average magnitude of prediction errors, in held-out data of 4.76 years and an R2 value of 0.92. Age prediction was highly accurate for the pediatric cohort (MAE = 0.87, R2 = 0.94) but inaccurate for ages 65+ (MAE = 4.30, R2 = 0.25). Variability was observed in which biomarkers carry predictive power across age groups, genders, and race/ethnicity groups, and novel candidate biomarkers of aging were identified for specific age ranges (e.g. Vitamin E, ages 18-44). We show that predictors for one age group may fail to generalize to other groups and investigate non-linearity in biomarkers near adulthood. As populations worldwide undergo major demographic changes, it is increasingly important to catalogue biomarker variation across age groups and discover new biomarkers to distinguish chronological and biological aging.

Roles of vitamins in stem cells

Stem cells can differentiate to diverse cell types in our body, and they hold great promises in both basic research and clinical therapies. For specific stem cell types, distinctive nutritional and signaling components are required to maintain the proliferation capacity and differentiation potential in cell culture. Various vitamins play essential roles in stem cell culture to modulate cell survival, proliferation and differentiation. Besides their common nutritional functions, specific vitamins are recently shown to modulate signal transduction and epigenetics. In this article, we will first review classical vitamin functions in both somatic and stem cell cultures. We will then focus on how stem cells could be modulated by vitamins beyond their nutritional roles. We believe that a better understanding of vitamin functions will significantly benefit stem cell research, and help realize their potentials in regenerative medicine.

The highly unnatural fatty acid profile of cells in culture

The fatty acid profile of cells in culture are unlike those of natural cells with twice the monounsaturated (MUFA) and half the polyunsaturated fatty acids (PUFA) level (Mol%). This is not due to cell lines primarily being derived from cancers but is due to limited access to lipid and an inability to make PUFA de novo as vertebrate cells. Classic culture methods use media with 10% serum (the only exogenous source of lipid). Fetal bovine serum (FBS), the serum of choice has a low level of lipid and cholesterol compared to other sera and at 10% of media provides 2-3% of the fatty acid and cholesterol, 1% of the PUFA and 0.3% of the essential fatty acid linoleic acid (18:2n-6) available to cells in the body. Since vertebrate cell lines cannot make PUFA they synthesise MUFA, offsetting their PUFA deficit and reducing their fatty acid diversity. Stem and primary cells in culture appear to be similarly affected, with a rapid loss of their natural fatty acid compositions. The unnatural lipid composition of cells in culture has substantial implications for examining natural stems cell in culture, and for investigations of cellular mechanisms using cell lines based on the pervasive influence of fats.

Control of antioxidant supplementation through interview is not appropriate in oxidative-stress sport studies: Analytical confirmation should be required

OBJECTIVE

Controlling antioxidant supplementation in athletes involved in studies related to oxidative stress and muscle damage is the key to ensure results. The aim of this study was to confirm through high-performance liquid chromatography (HPLC) analysis whether well-trained individuals lied during a personal interview when asked if they were taking supplements with antioxidants, and how this could affect oxidative stress, muscle damage, and antioxidant response.

METHODS

A total of 94 men, well trained in endurance sports, volunteered in this study. They denied taking any antioxidant supplementation at initial interview. After a HPLC analysis, abnormal α-tocopherol concentrations were detected, probably due to a hidden antioxidant supplementation. Participants were classified into two groups: no evidence of antioxidant supplementation (NS group = α-tocopherol values <80 nmol/mL; n = 75) and evidence of antioxidant supplementation (S group = α-tocopherol values >80 nmol/mL; n = 19). Lipid peroxidation, muscle damage, antioxidant enzyme activity, and nonenzymatic antioxidant content were analyzed according to this classification. Statistical comparisons were performed using Student's t test.

RESULTS

The α-tocopherol concentrations were significantly higher in the S group than in the NS group (MD = 725.01 ± 39.01 nmol/mL; P = 0.001). The S group showed a trend toward lower hydroperoxides than the NS group (MD = 1.19 ± 0.72 nmol/mL; P = 0.071). The S group showed significantly lower catalase activity than the NS group (MD = 0.10 ± 0.02-seg-1 mg-1; P < 0.01). Skeletal muscle damage markers did not differ between experimental groups.

CONCLUSIONS

Data from the present study reveal that 20% of participants lied in the exclusion criteria of antioxidant supplementation in a personal interview, as they showed high plasmatic α-tocopherol concentrations after HPLC verification. Catalase activity seems to be affected by high α-tocopherol plasma levels. Therefore, we strongly recommend the HPLC analysis as a necessary tool to verify the antioxidant intake and preserve results in studies linking oxidative stress and sport.

Plasma n-3 polyunsaturated fatty status and its relationship with vitamin E intake and plasma level

PURPOSE

The aim of the study was to investigate habitual vitamin E intake and plasma α-tocopherol concentration and their relationship with plasma fatty acid profile in a healthy adult population.

METHODS

Vitamin E and fatty acid intake data were determined from the National Adult Nutrition Survey. Plasma α- and γ-tocopherol concentrations were quantified by high-performance liquid chromatography and the percentage of fatty acids in plasma by gas chromatography coupled with mass spectrometry. Participants (n = 601) were divided into vitamin E intake quartiles and plasma α-tocopherol quartiles, and differences in fatty acid intake and plasma fatty acid profile were analyzed by a general linear model.

RESULTS

Dietary intake data showed that as vitamin E intake increased, intakes of total polyunsaturated fatty acid (PUFA) and α-linolenic acid increased significantly (p < 0.001), but eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) did not. After adjusting for fatty acid intake, vitamin E intake was positively related to plasma n-3 PUFA (EPA and DHA) levels and plasma n-3/n-6 PUFA ratio. Plasma α-tocopherol concentration was positively related to the percentage of plasma total PUFA, n-3 PUFA and EPA and inversely related to the percentage of plasma n-6 PUFA.

CONCLUSIONS

The study illustrates that there are statistical relationships between plasma fatty acid profile and both vitamin E intake and plasma α-tocopherol concentration. Vitamin E may play a role in the maintenance of plasma n-3 PUFA profile in humans with consequent desirable health effects.

Lipid-soluble nutrient status of healthy Omani school children before and after intervention with oily fish meal or re-esterified triacylglycerol fish oil

OBJECTIVES

Over the past two decades, the Omani diet has changed considerably to resemble a high calorie and a low nutrient density Western diet. We investigated the fat soluble nutrient status of children before and after intervention with fish diet or fish oil.

METHODS

Children ages 9 and 10 y (n = 314) were recruited from three randomly selected schools. The schools were assigned to a fish, fish oil, or control group and the children were given a lightly grilled oily fish, a re-esterified triacylglycerol fish oil capsule, or no fish for 12 wk.

RESULTS

Plasma vitamin A, beta carotene, vitamin E concentrations, and vitamin E/total lipid ratio at baseline were 2.7 ± 0.85 μmol/L, 0.68 ± 0.48 μmol/L, 21.1 ± 4.8 μmol/L, and 5.0 ± 0.81 μmol/mmol, respectively, and none of the children were deficient. They were severely deficient (<27.5 nmol/L; 10.5% boys and 28.5% girls), deficient (27.5-44.9 nmol/L; 47.6% boys and 49.4% girls) or insufficient (50-74.9 nmol/L; 34.6% boys and 21.5% girls) in vitamin D; only 7.3% boys and 0.6% girls had optimal status (≥75 nmol/L). Parathyroid hormone (5.0 ± 1.7 versus 5.8 ± 2.1 pmol/L; P < 0.0001) and alkaline phosphatase (225.2 ± 66.6 versus 247.8 ± 73.7 U/L; P < 0.01) levels were lower in boys. Postintervention, the fish oil (54.1 ± 17.5 nmol/L; P < 0.001) and fish (49.2 ± 17.4 nmol/L; P < 0.05) groups had elevated levels of vitamin D compared with the controls (42.3 ± 17.5 nmol/L).

CONCLUSIONS

Vitamin D deficiency is prevalent in Omani school children, but it can be mitigated with omega-3 fatty acid supplementation. Vitamin D plays a crucial role in skeletal and extraskeletal systems. Hence, there is a need for a child-focused program of food fortification and outdoor activities to alleviate the problem.

Effect of vitamin E intake from food and supplement sources on plasma α- and γ-tocopherol concentrations in a healthy Irish adult population

Vitamin E is believed to play a preventive role in diseases associated with oxidative stress. The aims of the present study were to quantify vitamin E intake levels and plasma concentrations and to assess dietary vitamin E adequacy in Irish adults. Intake data from the National Adult Nutrition Survey were used; plasma samples were obtained from a representative cohort of survey participants. Plasma α- and γ-tocopherol concentrations were measured by HPLC. The main sources of vitamin E in the diet were ‘butter, spreadable fats and oils’ and ‘vegetables and vegetable dishes’. When vitamin E intake from supplements was taken into account, supplements were found to be the main contributor, making a contribution of 29·2 % to vitamin E intake in the total population. Supplement consumers had significantly higher plasma α-tocopherol concentrations and lower plasma γ-tocopherol concentrations when compared with non-consumers. Consumers of ‘vitamin E’ supplements had significantly higher vitamin E intake levels and plasma α-tocopherol concentrations compared with consumers of other types of supplements, such as multivitamin and fish oil. Comparison with the Institute of Medicine Estimated Average Requirement of 12 mg/d indicated that when vitamin E intake from food and supplement sources was taken into account, 100 % of the study participants achieved the recommended intake levels. When vitamin E intake from food sources was taken into account, only 68·4 % of the females were found to achieve the recommended intake levels compared with 99·2 % of the males. The results of the present study show that dietary vitamin E intake has a significant effect on plasma α- and γ-tocopherol concentrations. Furthermore, they show that the consumption of supplements is a major contributor to overall intake and has a significant effect on plasma vitamin E concentrations in the Irish population.

Vitamin E deficiency in developing countries

In addition to its role as a potent antioxidant, vitamin E is involved in a wide range of physiological processes, ranging from immune function and control of inflammation to regulation of gene expression and cognitive performance. Results from multiple studies suggest that poor nutritional status and higher prevalence of other oxidative stressors such as malaria and HIV infection predispose populations in developing countries for vitamin E deficiency. Although direct comparison between study outcomes is complicated by varied definitions of vitamin E deficiency, data trends indicate that children and the elderly are more vulnerable age groups and that men may be at higher risk for deficiency than women. Public health initiatives aimed at improving the vitamin E status of high-risk populations in developing countries would be prudent to counteract oxidative stress, improve immune function, and protect against neurologic and cognitive deficits. Additional research is needed to establish dose-response relationships of various interventions and to develop cost-effective, culturally-appropriate, and targeted programs.

Antioxidant status, oxidative stress, and damage in elite kayakers after 1 year of training and competition in 2 seasons

The large volume of training performed by elite athletes throughout the season can translate into a chronic oxidative insult. To study the effects that chronically high training loads have on athletes’ redox status, superoxide dismutase (SOD), glutathione reductase, glutathione peroxidase (GPx), and creatine kinase activities; total antioxidant status (TAS); and uric acid, retinol, α-tocopherol, α-carotene, β-carotene, lycopene, lutein + zeaxanthin, vitamin C, thiobarbituric acid reactive substances (TBARS), interleukin-6, and cortisol levels were determined in 9 kayakers (6 men) in a competitive period during the first season (June, T1), and in precompetitive (March, T2) and competitive (June, T3) periods during the following season. TAS decreased from the first to the second season (T1 vs. T2, p < 0.001; T1 vs. T3, p < 0.001). TBARS (p = 0.024) decreased from T1 to T2. The α-tocopherol increase (p = 0.001) from T1 to T2 lost statistical significance after adjustment for total lipids (p = 0.243). GPx (p = 0.003) increased, while SOD (p < 0.001) and uric acid (p = 0.032) decreased from T2 to T3. Cortisol levels decreased significantly throughout the study (T1 vs. T2, p = 0.042; T2 vs. T3, p = 0.018; T1 vs. T3, p = 0.002). No significant differences were observed for any of the other parameters studied. Antioxidant status changed more within the same season than from one season to another. Redox markers should be monitored throughout the season to detect athletes at an increased oxidative risk.

Contents of vitamin C, carotenoids, tocopherols, and tocotrienols in the subtropical plant species Cyphostemma digitatum as affected by processing

The subtropical plant species Cyphostemma digitatum, Vitaceae, is used in central Yemen in traditional medicine, as a culinary herb, and as a source of food flavoring. The contents of vitamin C, vitamin E, and carotenoids and changes caused by common processing were investigated. Carotenoids were determined by reversed phase C30-high-performance liquid chromatography (HPLC) with diode array detection at 470 nm, while tocopherols and tocotrienols were analyzed by using normal phase HPLC with fluorescence detection (excitation, 292 nm; emission, 330 nm). Ascorbic acid was determined spectrophotometrically after reaction with DNP by measuring the absorbance at 520 nm. For the raw material and for the processed commercial food product, both in dried form, reasonable quantities of carotenoids were found in the raw material as follows: lutein, 18.89 +/- 0.73 mg/100 g; zeaxanthin, 9.46 +/- 0.30 mg/100 g; canthaxanthin, 0.21 +/- 0.01 mg/100 g; beta-cryptoxanthin, 0.67 +/- 0.03 mg/100 g; and beta-carotene, 14.60 +/- 0.46 mg/100 g. Household processing reduced the carotenoid contents dramatically; only beta-carotene sustained the processing. Likewise, vitamin C, 49.50 +/- 0.01 mg/100 g in the raw material and 20.30 +/- 0.02 mg/100 g in the processed material, was affected negatively by processing; only 41% was retained after processing. In contrast, the outstanding high content of vitamin E, 82.74 +/- 0.63 mg/100 g in the raw material, was increased by processing to 101.20 +/- 1.38 mg/100 g; it was found in different forms, some of which were rare in other sources.

Effects of orlistat therapy on plasma concentrations of oxygenated and hydrocarbon carotenoids

Orlistat is a lipase inhibitor that is applied for treating obesity. Lipases are required for digestion and absorption of dietary lipids and fat-soluble vitamins and carotenoids. The aim of this study was to compare the effects of orlistat therapy on plasma concentrations of oxygenated (beta-cryptoxanthin, lutein/zeaxanthin) and hydrocarbon (alpha-, beta-carotene, lycopene) carotenoids. Six patients with a body mass index (BMI) > or = 30 kg/m2 received 360 mg/d orlistat over 4.5 mon. Plasma carotenoid concentrations were determined at baseline (T0) and after 3 (T3) and 4.5 mon (T4.5) along with anthropometric, dietary, and biochemical indices, including plasma lipids, retinol, (alpha- and gamma-tocopherols, and FA. Baseline BMI was 32.7 +/- 1.97 kg/m2. Five of six patients lost weight; the average weight loss was 3.6 +/- 2.4% (P = 0.47). There were no significant changes in dietary carotenoid intakes. In contrast, plasma alpha- and beta-carotene concentrations decreased significantly from T0 to T4.5 by 45% (P = 0.006) and 32% (P = 0.013), respectively. Plasma lycopene decreased from T0 to T3 but increased again from T3 to T4.5, while beta-cryptoxanthin and lutein/zeaxanthin concentrations did not change. There were no significant alterations in tocopherol, retinol, and FA concentrations. In conclusion, even though weight loss was not significant, orlistat therapy was associated with significant decreases in plasma concentrations of the highly lipophilic hydrocarbon carotenoids, alpha- and beta-carotene.

Age-related changes in plasma lycopene concentrations, but not in vitamin E, are associated with fat mass

The aim of the present study was to assess the influence of age on plasma concentration of α-tocopherol, retinol and carotenoids with a special attention paid to natural differences in body composition. Forty healthy subjects were recruited: twenty were less than 35 years old and twenty above 60 years old. Males and females were equally represented in each age group. Subjects were kept in energy balance and received controlled diets for 36 h. Fat mass and fat-free mass were determined with the180-enriched water dilution technique. Plasma vitamins A and E, and carotenoid levels were determined after 12 h fasting and were shown to be similar in women and men. Plasma α-tocopherol concentration increased with age (+44 % elderlyv.young), and correlated with % fat mass and plasma cholesterol. After adjustment for plasma cholesterol, the effect of age and % fat mass disappeared. In contrast, plasma lycopene level was 2-fold lower in the elderly than in the young group, and was inversely correlated with fat mass. When lycopene values were adjusted for fat mass, the effect of age disappeared. These results suggest that plasma levels of vitamin E and lycopene differed in the two age groups and that differences in plasma cholesterol and fat mass might participate in such an effect. Short-term vitamin intake did not appear to influence plasma vitamin concentrations.

Factors influencing blood concentration of retinol, alpha-tocopherol, vitamin C, and beta-carotene in the French participants of the SU.VI.MAX trial

OBJECTIVES

The data was collected during the inclusion step of the SUpplémentation en VItamines et Minéraux AntioXydants (SU.VI.MAX) study. This article deals with the study's first stage before any supplementation. The collected data shows factors influencing blood vitamin concentrations and may reflect the vitamin status of volunteers.

MATERIAL AND METHODS

A total of 12,741 volunteers were enrolled in the SU.VI.MAX study 7,713 women 35-60 years of age and 5,028 men 50-60 years of age. The serum concentrations of retinol, alpha-tocopherol, and beta-carotene were measured by HPLC, and vitamin C concentration was measured by spectrofluorimetry using a Technicon continuous flow analysis apparatus. The volunteers recorded their 24 h diet by means of a specific terminal that was connected to the main central computer of the SU.VI.MAX study. Volunteers recorded the food they consumed daily and estimated its quantity by comparing pictures of dishes.

RESULTS

Retinol concentration was significantly higher in older volunteers, and was higher in male than in female volunteers. Smoking had no effect on serum retinol, but the latter was higher in the autumn than in the winter. Serum retinol concentrations were higher in the Southwest region and lower in the Ile-de-France and East-Centre regions. Serum alpha-tocopherol was slightly higher in older volunteers and also higher in male volunteers. Serum alpha-tocopherol was significantly lower in smokers, and former smokers showed intermediate levels. Like retinol, serum alpha-tocopherol was higher in the autumn, and higher in the Southwest as compared to the East-Centre Serum beta-carotene was slightly higher in younger volunteers, and concentrations were higher in female than in male volunteers. Tobacco smoking decreased serum beta-carotene, which was higher in the autumn, and higher in the East, West, and North regions. Serum vitamin C was higher in female volunteers, and was not age related. Serum vitamin C was lower in smokers, was season-dependant, but contrary to fat-soluble vitamins, concentrations were higher in the winter and spring. Serum vitamin C was higher in the Southeast and East-Centre, but lower in the North region.

CONCLUSION

These results suggest that serum retinol concentrations depend on gender, age, seasons, and location of residence. Similarly, serum alpha-tocopherol concentrations were slightly influenced by age, but more by tobacco smoking, seasons, dietary intake, and location of residence. Serum concentrations of beta-carotene depend on gender, age, smoking status, dietary intake, and location of residence. Serum vitamin C concentrations depend on gender, age, smoking status, seasons, dietary intake, and location of residence. Contrary to beta-carotene, retinol concentrations were higher in male than in female volunteers. Such a reversed relation suggests a higher beta-carotene-retinol conversion in male volunteers.

Does aging affect the response of vitamin E status to vitamin E depletion and supplementation?

A vitamin E depletion/supplementation study was conducted in 100 healthy 20-75-year-old volunteers. The responses of vitamin E status to 3-week dietary vitamin E restriction to approximately 25% of recommended intake and 2-month unrestricted dietary intake plus 800 IU/d of RRR-alpha-tocopherol were studied as a function of age. Plasma alpha-tocopherol concentrations were closely related to cholesterol concentrations, which increased with age (P < 0.001). Upon dietary restriction, plasma alpha-tocopherol concentrations decreased significantly (P < 0.001) but independently of age. Plasma alpha-tocopherol responses to supplementation increased significantly with age, but this effect disappeared after standardization for cholesterol. gamma-Tocopherol concentrations decreased to less than 30% of baseline.

Effect of cigarette smoking on serum α-tocopherol and the lipid profile in a Portuguese population

BACKGROUND

The present study was conducted to determine the effects of cigarette smoking on the levels of serum alpha-tocopherol and on the lipid profile in humans from the Lisbon population.

METHODS

Serum alpha-tocopherol was evaluated by a reverse-phase HPLC method with UV detection. Enzymatic tests were used for the evaluation of the lipid profile.

RESULTS

Smokers in general and female smokers in particular had decreased alpha-tocopherol levels when compared with nonsmokers. Smokers had also lower HDL cholesterol (HDL-C) contents, but this difference was statistically significant only for females. Regardless of sex, in smokers, there was a positive correlation between alpha-tocopherol and triglyceride (TG) levels. Cluster analysis showed a sex-independent separation between smokers and nonsmokers.

CONCLUSION

These results suggest a different interaction of these blood parameters in smokers versus nonsmokers that should be further investigated.

Aging and oxidative stress

The scientific establishment has been discussing the relationship between aging and oxidative stress for quite some time now. While we are still far from a general agreement about this subject, there is an impressive amount of data collected that can be used to draw a compelling picture of the events that take place during the human aging process and their correlation with the oxidant status of the organism. In this review, we bring forth the results of some key studies that can help to elucidate the aging-oxidative stress puzzle, as well as to explain which are the fundamental events in this interplay and why their causal relationships remain so elusive. We also put forward here data on the systemic oxidative stress status of a group of 503 healthy human subjects. The data consist of the plasma levels of TBARS and of the nutritional antioxidants, alpha-tocopherol, beta-carotene and ascorbic acid, and of the activity of the antioxidant enzymes, Cu, Zn-superoxide dismutase, catalase and glutathione peroxidase, of red blood cells. The data indicate that a moderate situation of oxidative stress gradually develops during human aging.

Oxidative stress: potential of distinct peroxide determination systems

When reactive oxygen species attack biological structures, peroxides, which are short-lived oxidative intermediates, are generated. We evaluated the potential of two different, commercially available peroxide activity assays (Pox-Act and d-ROMS) to see whether the results were associated with the clinical condition of subjects who were participating in a routine health care program. Furthermore, we determined the total antioxidant status (TAS) and the titer of autoantibodies against oxidized low-density lipoprotein (oLAb) to verify the hydroperoxide measurements.

Subjects with medical conditions (hereafter referred to as patients) had significantly increased serum peroxide levels compared to healthy subjects. The d-ROMS kit indicated that 86% of subjects had an increased level of total peroxides. Although the assays had a significant correlation (p < 0.001), 34% of the subjects had an increased total peroxide concentration in the Pox-Act assay that was clearly associated with clinical symptoms. Furthermore, the sensitivity of the Pox-Act assay was 35 times higher than that of the d-ROMS kit. In subjects with medical conditions, there was a trend toward a decreased TAS and a slightly increased oLAb titer in comparison to healthy subjects, but this was not statistically significant. The Pox-Act assay seems to be a valuable tool for the determination of total peroxides, while the results from the d-ROMS kit should be considered with caution.

Plasma levels and redox status of coenzyme Q10 in infants and children

INTRODUCTION

Increased attention has been paid to the role of lipophilic antioxidants in childhood nutrition and diseases during recent years. The lipophilic antioxidant coenzyme Q10 (CoQ10) is known as an effective inhibitor of oxidative damage. In contrast to other lipophilic antioxidants like alpha-tocopherol the plasma concentrations of CoQ10 in childhood are poorly researched. The aim of this study was to determine plasma level and redox status (oxidized form in total CoQ10 in %) of CoQ10 in clinically healthy infants, preschoolers and school-aged children.

METHODS

Plasma level and redox status of CoQ10 were measured by HPLC in 199 clinically healthy children, three groups of infants [1st-4th month (n = 35), 5th-8th month (n = 25), 9th-12th month (n = 25) ], preschoolers (n = 60) and school-aged children (n = 54). The CoQ10 plasma levels were related to plasma cholesterol concentrations. The median and the 5th and 95th percentile were calculated.

RESULTS

Plasma levels and redox status of CoQ10 in infants were significantly higher than in preschoolers and school-aged children. The CoQ10 redox status in the 1st-4th month was significantly increased when compared to the remaining subgroups of infants. In elder children the CoQ10 redox status stabilized.

CONCLUSIONS

This is the first study concerning age-related values of plasma level and redox status of CoQ10 in apparently healthy children. Decreased CoQ10 values could be involved in various pathological conditions affecting childhood. Therefore, the application of age-adjusted reference values may provide more specific criteria to define threshold values for CoQ10 deficiency in plasma.

Simultaneous Determination of Tocotrienols, Tocopherols, Retinol, and Major Carotenoids in Human Plasma

Background: Epidemiologic evidence suggests that the concentrations of antioxidant vitamins in human plasma may play an important role in numerous chronic diseases, such as cancer and cardiovascular disease. However, methods for simultaneous measurement of these antioxidants are scarce. We developed and validated a new HPLC method for simultaneous determination of these vitamers in human plasma that uses a novel column-switching approach.

Methods: The new method uses liquid–liquid extraction and isocratic separation with two monomeric C18 columns maintained at 35 and 4 °C coupled with ultraviolet–visible and fluorometric detection. This method could separate 14 vitamers and 3 internal standards within 27 min. No additional modifier was required; the mobile phase was acetonitrile–methanol (65:35 by volume), and the flow rate was 1 mL/min.

Results: For photodiode array detection, the detection limits (signal-to-noise ratio &gt;3) were 0.02 mg/L for β-carotene, lutein, zeaxanthin, and canthaxanthin; 0.01 mg/L for all-trans-retinol, β-cryptoxanthin, α-carotene, and lycopene; and 0.1 mg/L for all tocopherols and tocotrienols. The detection limit was at least 25-fold lower (0.004 mg/L) when fluorometry was used for measurement of δ-, γ-, and α-tocotrienol and δ-tocopherol compared with ultraviolet detection. The recovery and imprecision of the assay were generally &gt;90% and &lt;10%, respectively.

Conclusions: This new method separates a wide range of fat-soluble antioxidant vitamins in human plasma, including six carotenoids, three isoforms of tocotrienols and tocopherols (δ-, γ-, and α-), and all-trans-retinol. The overall findings suggest that our method is faster, more sensitive, and more comprehensive than existing methods.

Pharmacology of all-trans-retinoic acid in children with acute promyelocytic leukemia

BACKGROUND

Due to severe side effects in virtually all children treated with a standard dose of 45 mg/m(2)/day all-trans-retinoic acid (ATRA) for acute promyelocytic leukemia (APL) the AML-BFM study group reduced the dosage to 25 mg/m(2)/day. For the lack of data on the use of ATRA at this dosage in children with APL, the study group further decided to evaluate the pharmacokinetics and metabolism of ATRA in children.

PROCEDURE

Twenty-three pharmacokinetic and metabolic profiles of ATRA were studied in 14 children (aged 0.9-18.4 years) with APL. Eleven plasma samples were collected over a period of 8 hr and analyzed for ATRA and its metabolites by high-performance liquid chromatography.

RESULTS

Peak plasma concentrations of ATRA were characterized by wide interpatient variability (range: 28.6-513.0 nM). Compared to adults the same metabolic pathways were observed in children. Even though peak plasma concentrations were in the lower range of those considered effective in vitro, ATRA side effects, notably neurotoxicity, still required dose reduction, treatment break, or drug withdrawal in eight patients. In this small number of patients, neurotoxicity could not be related to age or any specific level of ATRA or metabolites in the plasma. Plasma concentrations of vitamin A, however, were significantly higher in those patients, who developed signs of neurotoxicity (P = 0.03, Mann-Whitney Rank Sum test).

CONCLUSIONS

Considering the low plasma concentrations and the persistence of toxicity in spite of dose reduction intermittent dosing schedules might be considered as an alternative to further dose reduction of ATRA in the treatment of APL especially in children, who might be at risk of ATRA-induced neurotoxicity.

Serum concentrations of micronutrient antioxidants in an adult Arab population

Serum concentrations of retinol, alpha-tocopherol, beta-carotene and lycopene were measured by reversed-phase high-performance liquid chromatography (r-P HPLC) in 260 randomly selected healthy adult Kuwaitis (159 men and 101 women) aged 18-63 years (mean 33.3 years) to established reference ranges of the micronutrient antioxidants. Total cholesterol concentrations were assayed by an enzymatic method to determine alpha-tocopherol: cholesterol ratios. The mean +/- SEM (micromol/L) for retinol, alpha-tocopherol, beta-carotene and lycopene were 1.76+/-0.02, 20.0+/-0.5, 0.52+/-0.03, 0.95+/-0.05, respectively. Compared to other populations, these data showed, on the whole, ordinary concentrations of beta-carotene, comparatively low concentrations of retinol and alpha-tocopherol and high concentrations of lycopene. Retinol concentrations were similar for both sexes, whereas alpha-tocopherol concentration was significantly (P < 0.0001) lower and the carotenoid levels (beta-carotene and lycopene) significantly higher (P < 0.0001) in women. Of the micronutrient antioxidants, alpha-tocopherol was most correlated with cholesterol (r = 0.492, P < 0.0001). beta-Carotene and lycopene were highly correlated with each other (r =0.744, P< 0.0001). Age was positively associated with beta-carotene (r = 0.214, P = 0.001) and lycopene (r = 239, P< 0.0001). Our data enabled us to establish a gender non-specific reference range for retinol and gender-specific reference ranges for alpha-tocopherol, beta-carotene and lycopene.

Lipid peroxidation and antioxidant status in professional American football players during competition

BACKGROUND

Oxidative stress occurs during strenuous physical exercise, perhaps as a result of increased consumption of oxygen.

MATERIALS AND METHODS

In this study, different markers of oxidative stress were determined in eight national league American football players. Before (March) and at three time-points during the competition season (May, June, July) serum total peroxide concentrations, auto-antibody titres against oxidized low-density lipoprotein (oLab), and lag time of reactive oxygen species-induced degradation of the fluorophore 1-palmitoyl-2-((2-(4-(6-phenyl-trans-1,3,5-hexatrienyl)phenyl)ethyl)- carbonyl)-sn-glycero-3-phosphocholine (DPHPC) were measured along with serum ascorbate, alpha- and gamma-tocopherol, and beta-carotene concentrations.

RESULTS

Before the competition season, serum antioxidant concentrations were within the lower normal range; ascorbate concentrations increased significantly during the competition period (P < 0.05). Serum peroxide concentrations were within the normal range and increased significantly during the competition period (P < 0.05); in four of the eight subjects the increase was several times the baseline values, while four athletes did not show any increase. The oLab titres increased significantly at the mid-competition period time-point (P < 0.01), but levelled off thereafter.

DISCUSSION

Given that it could not be predicted from the baseline oxidative stress and antioxidant status which subject would respond to strenuous exercise with an increase in oxidative stress status, it is concluded that oxidative stress should be monitored in all athletes.

Methods for monitoring oxidative stress, lipid peroxidation and oxidation resistance of lipoproteins

After a brief discussion of lipid peroxidation mechanism and the action of antioxidants and their potential to exhibit prooxidant effects, we give an overview on the clinical relevance of oxidative stress parameters. Many diseases are associated with oxidative stress e.g. by radical damage, among them atherosclerosis, diabetes mellitus, chronic renal failure, rheumatoid arthritis, and neurodegenerative diseases, and in many cases the investigation of parameters of oxidative stress has brought substantial insights into their pathogenesis. We then briefly review methods for the continuous monitoring of lipid peroxidation processes in vitro, which has helped in elucidating their mechanism and in some more detail cover such methods which have been proposed more recently to assess oxidative status and antioxidant activity in biological samples.

Vitamin A and E supplementation in breast-fed newborns

BACKGROUND

Vitamins A and E are two potent antioxidant nutrients that play a significant role in immune function. In contrast to the numerous studies of vitamin A and E status in children, adolescents, and adults, information on term infants, particularly breast-fed infants, is scarce. The goals of the present investigation were to examine the vitamins A and E nutritional status of term breast-fed infants at birth and to assess retinol and tocopherol plasma levels during a 3-month supplementation trial.

METHODS

The study was a prospective, blinded comparison of a supplementation protocol with a placebo in a group of consecutively recruited term newborns. The supplemented group received 3000 IU vitamin A and 5 IU vitamin E orally. The placebo group received a solution of similar viscosity and organoleptic characteristics. Vitamin A and E were separated by reverse-phase high-performance liquid chromatography on a C18 Spectrasyl column and quantified by ultraviolet spectrophotometry.

RESULTS

Vitamin A and E levels steadily increased with age in both groups of infants. However, levels at 3 months were higher in the supplemented than in the control group.

CONCLUSION

The data show that supplementation with 3000 IU vitamin A and 5 IU vitamin E for 3 months increases circulating vitamin levels in newborn term babies compared with those in nonsupplemented infants.

Vitamin E and Coronary Heart Disease in Tunisians

Background: Vitamin E (VE) is thought to be effective in preventing atherosclerosis. However, to date no consistent relationship has been identified between VE and coronary heart disease (CHD). This study was designed to assess the degree of association between VE and CHD in a sample of the Tunisian population.

Methods: Sixty-two angiographically confirmed coronary atherosclerotic patients and 65 age- and sex-matched controls were included. VE was measured in plasma and in the LDL fraction by HPLC. Cholesterol, triglycerides, and phospholipids were measured by enzymatic methods.

Results: A trend toward a meaningful decrease of plasma VE was observed in affected patients compared with controls (P = 0.06). VE concentrations standardized for cholesterol and lipid concentrations were significantly lower (P &lt;0.02) in coronary patients than in controls (4.35 ± 1.03 vs 4.82 ± 1.23 mmol/mol for cholesterol-adjusted VE and 2.35 ± 0.56 vs 2.66 ± 0.65 mmol/mol for lipid-adjusted VE, respectively). In the LDL fraction, only cholesterol-standardized VE was significantly lower in cases than controls (3.84 ± 1.13 vs 4.41 ± 1.16 mmol/mol). This association between VE and CHD remained unchanged independent of age, sex, smoking habit, hypertension, and diabetes. In CHD patients, lower lipid-adjusted VE was associated with enhanced LDL susceptibility to oxidation but without alteration of the serum fatty acid profile.

Conclusions: These results support the hypothesis that VE plays a role in preventing atherosclerosis.

Vitamin E attenuates oxidative stress induced by intravenous iron in patients on hemodialysis

Intravenous iron application to anemic patients on hemodialysis leads to an "oversaturation" of transferrin. As a result, non-transferrin-bound, redox-active iron might induce lipid peroxidation. To test the hypothesis that vitamin E attenuates lipid peroxidation in patients receiving 100 mg of iron(III) hydroxide sucrose complex intravenously during a hemodialysis session, 22 patients were investigated in a randomized cross-over design, either with or without a single oral dose of 1200 IU of all-rac-alpha-tocopheryl acetate taken 6 h before the hemodialysis session. Blood was drawn before and 30, 60, 90, 135, and 180 min after the start of the iron infusion, and areas under the curve (AUC0-180 min) of ratios of plasma malondialdehyde (MDA) to cholesterol and plasma total peroxides to cholesterol (two markers of lipid peroxidation) were determined as the outcome variables. At baseline of the session without vitamin E supplementation, plasma alpha-tocopherol concentrations (27.6 +/- 1.8 micromol/L) and ratios of alpha-tocopherol to cholesterol (5.88 +/- 1.09 mmol/mol) were normal, plasma MDA concentrations were above normal (1.20 +/- 0.28 micromol/ L), and bleomycin-detectable iron (BDI), indicating the presence of redox-active iron, was not detectable. Upon iron infusion, BDI and MDA concentrations increased significantly (P < 0.001). BDI concentrations explained the increase over baseline in MDA concentrations (MDA = 1.29 +/- 0.075 x BDI). Vitamin E supplementation, leading to a 68% increase in plasma alpha-tocopherol concentrations, significantly reduced the AUC0-180 min of MDA to cholesterol (P = 0.004) and peroxides to cholesterol (P = 0.002). These data demonstrate that a single oral dose of vitamin E attenuates lipid peroxidation in patients on hemodialysis receiving intravenous iron. Given that intravenous iron is applied repeatedly to patients on hemodialysis, this therapeutic approach may protect against oxidative stress-related degenerative disease in the long term.

Mechanisms of vitamin E regulation: research over the past decade and focus on the future

This paper discusses the developments in human vitamin E research since 1990. New methodologies such as the use of stable isotopes, advances in vitamin E measurements, and isolation and cloning of specific alpha-tocopherol binding proteins have facilitated investigation of alpha-tocopherol absorption, metabolism, and transport in humans in vivo. Changes in food production in the United States and dietary intake impacted vitamin E availability and intake. Epidemiologic and therapeutic studies have pointed to its role in disease prevention and in healing processes. Specific molecular functions of alpha-tocopherol have been the most recent and surprising new findings and are an important area for future experimentation. Given the aging of the American population and the potential role for alpha-tocopherol in preventive medicine, the study of the molecular functions of vitamin E promises to provide some of the most exciting discoveries of the next decade.

A pilot study of garlic consumption shows no significant effect on markers of oxidation or sub-fraction composition of low-density lipoprotein including lipoprotein(a) after allowance for non-compliance and the placebo effect

Our aim was to define any effects of confirmed garlic supplementation on the resistance of low density lipoprotein (LDL) to oxidation, on LDL sub-fraction composition including levels of lipoprotein(a), and on levels of circulating antibody to oxidised LDL, variables of interest in relation to cardiovascular risk. Additional tests were performed on samples collected from a double blind, randomised 6-month parallel trial in which 900 mg Kwai garlic or placebo was taken by moderately hypercholesterolaemic volunteers. Final data was analysed for 20 garlic and 11 placebo subjects with compliance of at least 75% as determined by repeat tablet counting. EDTA plasma stabilised by sucrose was stored at -70 degrees C for up to 12 months. Lipids and apolipoproteins were determined by standard methods, lipoprotein(a) by an ELISA method and LDL fraction composition by non-gradient gel electrophoresis. Oxidative resistance of LDL purified after isolation by density gradient centrifugation was assessed from oxidative resistance to copper ions determined spectrophotometrically, antibodies to oxidised LDL were determined by a microtitre plate assay and vitamin E content of plasma by HPLC. Overall lipid/lipoprotein profiles including lipoprotein(a) were unchanged as with the parent group. LDL composition showed a trend to less dense material in both placebo and garlic groups, all differences not significant. Lag time as a marker of oxidative resistance also increased in both groups, without change in vitamin E content, all differences not significant and consistent with a placebo effect. Levels of antibodies to oxidised LDL were unchanged. The results of this study do not support the hypothesis that dietary garlic supplementation decreases the susceptibility of isolated LDL to oxidation and that patterns of LDL tractions in plasma might be involved. Levels of lipoprotein(a) in plasma were also not changed. Other mechanisms of cardiovascular benefit are however not excluded.

Utility of produce ratios to track fruit and vegetable consumption in a rural community, church-based 5 A Day intervention project

Previous research suggests that grocery store characteristics may be useful in evaluating community-based dietary interventions. We undertook a study to determine whether produce ratios (ratios of produce sales to total grocery sales) were a useful indicator of fruit and vegetable (F & V) consumption in a church-based, community intervention trial that promoted 5 A Day guidelines within 10 rural counties of North Carolina. Produce ratios were collected from stores identified by participants in the Black Churches United for Better Health Project. Baseline and study period data for 21 stores in intervention counties and 18 stores in nonintervention counties were compared using repeated-measures analysis of variance. Produce ratios were significantly associated with seasonality (p < 0.0001), but no differences were seen between the two groups of stores. These findings do not support data from individual telephone surveys, which showed significant differences in F & V consumption between participants in the two groups. Our inability to detect differences at the store level may have been due to 1) the incapacity of produce ratios to capture F & V purchases that were juice, frozen, or canned products; 2) shifts in procuring F & Vs from grocery stores to other sources (i.e., gleaning and produce cooperatives); 3) the modest proportion of shoppers that received the full intervention dose; and 4) a general lack of power to detect differences at the store level. Therefore, although produce ratios did not serve as a valid measure for this project, if their limitations are recognized and compensated for, they may have applicability for future investigations that monitor F & V consumption.

Optimal nutrition: vitamin E

Interest in the role of vitamin E in disease prevention has encouraged the search for reliable indices of vitamin E status. Most studies in human subjects make use of static markers, usually alpha-tocopherol concentrations in plasma or serum. Plasma or serum alpha-tocopherol concentrations of < 11.6, 11.6-16.2, and > 16.2 mumol/l are normally regarded as indicating deficient, low and acceptable vitamin E status respectively, although more recently it has been suggested that the optimal plasma alpha-tocopherol concentration for protection against cardiovascular disease and cancer is > 30 mumol/l at common plasma lipid concentrations in combination with plasma vitamin C concentrations of > 50 mumol/l and > 0.4 mumol beta-carotene/l. Assessment of vitamin E status has also been based on alpha-tocopherol concentrations in erythrocytes, lymphocytes, platelets, lipoproteins, adipose tissue, buccal mucosal cells and LDL, and on alpha-tocopherol: gamma-tocopherol in serum or plasma. Erythrocyte susceptibility to haemolysis or lipid oxidation, breath hydrocarbon exhalation, oxidative resistance of LDL, and alpha-tocopheryl quinone concentrations in cerebrospinal fluid have been used as functional markers of vitamin E status. However, many of these tests tend to be non-specific and poorly standardized. The recognition that vitamin E has important roles in platelet, vascular and immune function in addition to its antioxidant properties may lead to the identification of more specific biomarkers of vitamin E status.