Influence of SNPs in nutrient-sensitive candidate genes and gene–diet interactions on blood lipids: the DiOGenes study

Blood lipid response to a given dietary intervention could be determined by the effect of diet, gene variants or gene–diet interactions. The objective of the present study was to investigate whether variants in presumed nutrient-sensitive genes involved in lipid metabolism modified lipid profile after weight loss and in response to a given diet, among overweight European adults participating in the Diet Obesity and Genes study. By multiple linear regressions, 240 SNPs in twenty-four candidate genes were investigated for SNP main and SNP–diet interaction effects on total cholesterol, LDL-cholesterol, HDL-cholesterol and TAG after an 8-week low-energy diet (only main effect), and a 6-month ad libitum weight maintenance diet, with different contents of dietary protein or glycaemic index. After adjusting for multiple testing, a SNP–dietary protein interaction effect on TAG was identified for lipin 1 (LPIN1) rs4315495, with a decrease in TAG of − 0·26 mmol/l per A-allele/protein unit (95 % CI − 0·38, − 0·14, P= 0·000043). In conclusion, we investigated SNP–diet interactions for blood lipid profiles for 240 SNPs in twenty-four candidate genes, selected for their involvement in lipid metabolism pathways, and identified one significant interaction between LPIN1 rs4315495 and dietary protein for TAG concentration.

Short communication: plasma concentration of glucose-dependent insulinotropic polypeptide may regulate milk energy production in lactating dairy cows

In dairy cows, an increase in plasma concentration of glucose-dependent insulinotropic polypeptide (GIP) is associated with an increase in metabolizable energy intake, but the role of GIP in energy partitioning of dairy cattle is not certain. The objective of this study was to examine the relationship between plasma GIP concentrations and energy partitioning toward milk production. Four mid-lactation, primiparous, rumenfistulated Holstein-Friesian cows were fed a control diet of 55% forage and 45% concentrate [dry matter (DM) basis] in a 4 × 4 Latin square design with 4-wk periods. The 4 treatments were (1) control diet fed at 1000 and 1600 h, and (2) once-daily (1000 h) feeding, (3) twice daily (1000 and 1600 h) feeding, and (4) 4 times/d (1000, 1600, 2200 and 0400 h) feeding of the control diet plus 1 dose (1.75 kg on a DM basis at 0955 h) into the rumen of supplemental vegetable proteins (Amino Green; SCA NuTec Ltd., Thirsk, UK). Measurements of respiratory exchange and energy balance were obtained over 4 d during the last week of each period while cows were housed in open-circuit respiration chambers. Blood was collected from the jugular vein every 30 min for 12 h, using indwelling catheters, starting at 0800 h on d 20 of each period. Plasma GIP concentration was measured in samples pooled over each 5 consecutive blood samplings. The relationships between plasma GIP, DM intake, heat production, respiratory quotient, milk yield, and milk energy output were analyzed using linear correlation procedures, with metabolizable intake as a partial variant. Plasma GIP concentration was not correlated with heat production, or milk yield, but was positively correlated with milk energy yield (correlation coefficient = 0.67) and negatively correlated with RQ (correlation coefficient = −0.72). The correlations between GIP and RQ and milk energy output do not imply causality, but suggest that a role for GIP may exist in the regulation of energy metabolism in dairy cows.

Association of vitamin D status with arterial blood pressure and hypertension risk: a mendelian randomisation study

BACKGROUND: Low plasma 25-hydroxyvitamin D (25[OH]D) concentration is associated with high arterial blood pressure and hypertension risk, but whether this association is causal is unknown. We used a mendelian randomisation approach to test whether 25(OH)D concentration is causally associated with blood pressure and hypertension risk. METHODS: In this mendelian randomisation study, we generated an allele score (25[OH]D synthesis score) based on variants of genes that affect 25(OH)D synthesis or substrate availability (CYP2R1 and DHCR7), which we used as a proxy for 25(OH)D concentration. We meta-analysed data for up to 108 173 individuals from 35 studies in the D-CarDia collaboration to investigate associations between the allele score and blood pressure measurements. We complemented these analyses with previously published summary statistics from the International Consortium on Blood Pressure (ICBP), the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and the Global Blood Pressure Genetics (Global BPGen) consortium. FINDINGS: In phenotypic analyses (up to n=49 363), increased 25(OH)D concentration was associated with decreased systolic blood pressure (β per 10% increase, -0·12 mm Hg, 95% CI -0·20 to -0·04; p=0·003) and reduced odds of hypertension (odds ratio [OR] 0·98, 95% CI 0·97-0·99; p=0·0003), but not with decreased diastolic blood pressure (β per 10% increase, -0·02 mm Hg, -0·08 to 0·03; p=0·37). In meta-analyses in which we combined data from D-CarDia and the ICBP (n=146 581, after exclusion of overlapping studies), each 25(OH)D-increasing allele of the synthesis score was associated with a change of -0·10 mm Hg in systolic blood pressure (-0·21 to -0·0001; p=0·0498) and a change of -0·08 mm Hg in diastolic blood pressure (-0·15 to -0·02; p=0·01). When D-CarDia and consortia data for hypertension were meta-analysed together (n=142 255), the synthesis score was associated with a reduced odds of hypertension (OR per allele, 0·98, 0·96-0·99; p=0·001). In instrumental variable analysis, each 10% increase in genetically instrumented 25(OH)D concentration was associated with a change of -0·29 mm Hg in diastolic blood pressure (-0·52 to -0·07; p=0·01), a change of -0·37 mm Hg in systolic blood pressure (-0·73 to 0·003; p=0·052), and an 8·1% decreased odds of hypertension (OR 0·92, 0·87-0·97; p=0·002). INTERPRETATION: Increased plasma concentrations of 25(OH)D might reduce the risk of hypertension. This finding warrants further investigation in an independent, similarly powered study.

Iron deficiency anaemia and blood lead concentrations in Brazilian children

This study investigated the relationship between iron deficiency/iron deficiency anaemia, assessed by several parameters, and blood lead concentration in children. This cross-sectional study involved 384 Brazilian children, aged 2-11 years, who lived near a lead-manipulating industry. Complete blood counts were obtained by an automated cell counter. Serum iron, total iron binding capacity (TIBC) and ferritin were determined respectively, by colorimetric, turbidimetric methods and chemiluminescence. Blood lead was measured by atomic absorption spectrophotometry. The impact of several parameters for assessment of iron status (haemoglobin, serum iron, TIBC, transferrin saturation, ferritin, red cell indices and red cell distribution width) and variables (gender, age, mother`s education, income, body mass index, iron intake, and distance from home to lead-manipulating industry) on blood lead concentration was determined by multiple linear regression. There were significant negative associations between blood lead and the distance from home to the lead-manipulating industry (P < 0.001), Hb (P = 0.019), and ferritin (P=0.023) (R(2)=0.14). Based on these results, further epidemiological studies are necessary to investigate the impact of interventions like iron supplementation or fortification, as an attempt to decrease blood lead in children. (C) 2011 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

The influence of maternal factors on the concentration of vitamin A in mature breast milk

Background & aims: This study evaluated the relationship between vitamin A concentration in maternal milk and the characteristics of the donors of a Brazilian human milk bank. Material and methods: A total of 136 donors were selected in 2003-2004 for micronutrient determinations in breast milk and blood, anthropometric measurements and investigation of obstetric, socioeconomic-demographic factors, and life style. Maternal serum/milk samples were obtained for vitamin A, iron, copper, and zinc determinations. Vitamin A concentrations in breast milk and blood were assessed by high-performance liquid chromatography. Copper, zinc and iron concentrations in breast milk, and copper and zinc concentrations in blood were detected by atomic emission spectrophotometry. Serum ceruloplasmin and serum iron were determined, respectively, by nephelometry and colorimetry. A linear regression model assessed the associations between milk concentrations of vitamin A and maternal factors. Results: Vitamin A in milk presented positive associations with iron in milk (p < 0.001), serum retinol (p = 0.03), maternal work (p = 0.02), maternal age (p = 0.02). and oral contraceptive use (p = 0.01), and a negative association with % body fat (p = 0.01) (R(2) = 0.47). Conclusion: These results suggest that some nutritional, obstetric, and socioeconomic-demographic factors may have an effect on mature breast milk concentrations of vitamin A in apparently healthy Brazilian mothers. (C) 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Diapocynin versus apocynin as pretranscriptional inhibitors of NADPH oxidase and cytokine production by peripheral blood mononuclear cells

Apocynin has been extensively used as an inhibitor of NADPH oxidase (NOX) in many experimental models using phagocytic and non-phagocytic cells. Currently, there is some controversy about the efficacy of apocynin in non-phagocytic cells, but in phagocytes the reported results are consistent, which could be due to the presence of myeloperoxidase in these cells. This enzyme has been proposed as responsible for activating apocynin by generating its dimer, diapocynin, which is supposed to be the active compound that prevents NADPH oxidase complex assembly and activation. Here, we synthesized diapocynin and studied its effect on inhibition of gp91(phox) RNA expression. We found that diapocynin strongly inhibited the expression of gp91(phox)mRNA in peripheral blood mononuclear cells (PBMC). Only at a higher concentration, apocynin was able to exert the same effect. We also compared the apocynin and diapocynin efficacy as inhibitors of tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) production in response to lipopolysaccharide (LPS)-activated PBMC. Although apocynin did inhibit TNF-alpha production, diapocynin had a much more pronounced effect, on both TNF-alpha and IL-10 production. In conclusion, these findings suggest that the bioconversion of apocynin to diapocynin is an important issue not limited to enzymatic activity inhibition, but also for other biological effects as gp91(phox) mRNA expression and cytokine production. Hence, as diapocynin can be easily prepared from apocynin, a one-step synthesis, we recommend its use in studies where the biological effects of apocynin are searched. (C) 2010 Elsevier Inc. All rights reserved.

Effects of aerobic exercise on the blood pressure, oxidative stress and eNOS gene polymorphism in pre-hypertensive older people

The polymorphisms of endothelial nitric oxide synthase (eNOS) are associated with reduced eNOS activity. Aerobic exercise training (AEX) may influence resting nitric oxide (NO) production, oxidative stress and blood pressure. The purpose of this study was to investigate the effect of AEX on the relationship among blood pressure, eNOS gene polymorphism and oxidative stress in pre-hypertensive older people. 118 pre-hypertensive subjects (59 +/- A 6 years) had blood samples collected after a 12 h overnight fast for assessing plasma NO metabolites (NOx) assays, thiobarbituric acid reactive substances (T-BARS) and superoxide dismutase activity (ecSOD). eNOS polymorphism (T-786C and G-894T) was done by standard PCR methods. All people were divided according to the genotype results (G1: TT/GG, G2: TT/GT + TT, G3: TC + CC/GG, G4: TC + CC/GT + TT). All parameters were measured before and after 6 months of AEX (70% of VO(2 max)). At baseline, no difference was found in systolic and diastolic blood pressure, ecSOD and T-BARS activity. Plasma NOx levels were significantly different between G1 (19 +/- A 1 mu M) and G4 (14.2 +/- A 0.6 mu M) and between G2 (20.1 +/- A 1.7 mu M) and G4 (14.2 +/- A 0.6 mu M). Therefore, reduced NOx concentration in G4 group occurred only when the polymorphisms were associated, suggesting that these results are more related to genetic factors than NO-scavenging effect. After AEX, the G4 increased NOx values (17.2 +/- A 1.2 mu M) and decreased blood pressure. G1, G3 and G4 decreased T-BARS levels. These results suggest the AEX can modulate the NOx concentration, eNOS activity and the relationship among eNOS gene polymorphism, oxidative stress and blood pressure especially in C (T-786C) and T (G-894T) allele carriers.

Feed intake, growth, plasma glucose and urea nitrogen concentration, and cacass traits of lambs fed isoenergetic amounts of canola meal, soybean meal, and fish meal with forage based diet.

This experiment was conducted to examine the effect of feeding small, isoenergetic amounts of supplements containing high protein and functional lipid components, rather than the greater amounts of cereal and/or legume grains usually fed during the dry season in Australia, on dry matter intake (DMI), growth performance, plasma metabolites, and fat deposition in lambs consuming low quality roughage. Thirty two crossbred wether lambs ([Merino × Border Leicester] × Poll Dorset) were divided into four groups by stratified randomization according to liveweight (26–33 kg). After a 7-day adaptation to a hay diet (lucerne hay:oaten hay; 30:70), lambs were allocated to four treatments consisting of (1) basal diet of lucerne hay:oat hay (20:80; metabolizable energy (ME) = 7.0 MJ/kg DM), Basal; (2) basal + canola meal (84 g per day), CM; (3) basal + soymeal (75 g per day), SM; or (4) basal + fishmeal (80 g per day), FM. Daily hay and supplement DMI, and weekly liveweight were recorded during a 53-day experimental study. Blood samples were taken on day 1 and pre- and post-feeding on days 30 and 53 to measure changes in plasma glucose and plasma urea nitrogen (PUN) concentration. At the end of the experiment, lambs were slaughtered and hot carcass weight (HCW) recorded; cold carcass fatness (total muscle and adipose tissue depth at 12th rib, 110 mm from midline; GR) was determined at 24 h postmortem. Total DMI was increased (P < 0.001) in CM, SM and FM treatments, but basal hay DMI intake was only increased (P < 0.01) in CM and FM treatments compared with Basal treatment. This resulted in significant (P < 0.01) increases in metabolizable energy (ME) and crude protein (CP) intakes in all supplemented treatments, with the highest intakes recorded in the FM treatment. Liveweight gain (LWG) was significantly increased in CM and SM (P < 0.05) and FM (P < 0.01) treatments but HCW was significantly (P < 0.01) heavier slaughter only in the FM treatment. Feed conversion efficiency (P < 0.001) and GR fat at depth (P < 0.05) was reduced in all supplement treatments compared with Basal. Plasma glucose concentration was significantly (P < 0.05) increased after feeding in all treatments but there was no treatment effect. PUN was significantly increased over time in the supplemented treatments compared with the Basal treatment; there was no significant difference between supplement treatments by day 53. Results show that feeding small amounts of high protein and lipid-containing supplements improves production responses and are beneficial in producing carcasses with more lean compared with carcasses from lambs fed a low quality hay diet.

Local nitric oxide synthase inhibition reduces skeletal muscle glucose uptake but not capillary blood flow during in situ muscle contraction in rats

OBJECTIVE: We have previously shown in humans that local infusion of a nitric oxide synthase (NOS) inhibitor into the femoral artery attenuates the increase in leg glucose uptake during exercise without influencing total leg blood flow. However, rodent studies examining the effect of NOS inhibition on contraction-stimulated skeletal muscle glucose uptake have yielded contradictory results. This study examined the effect of local infusion of an NOS inhibitor on skeletal muscle glucose uptake (2-deoxyglucose) and capillary blood flow (contrast-enhanced ultrasound) during in situ contractions in rats.

RESEARCH DESIGN AND METHODS: Male hooded Wistar rats were anesthetized and one hindleg electrically stimulated to contract (2 Hz, 0.1 ms) for 30 min while the other leg rested. After 10 min, the NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) (arterial concentration of 5 µmol/l) or saline was infused into the epigastric artery of the contracting leg.

RESULTS: Local NOS inhibition had no effect on blood pressure, heart rate, or muscle contraction force. Contractions increased (P < 0.05) skeletal muscle NOS activity, and this was prevented by L-NAME infusion. NOS inhibition caused a modest significant (P < 0.05) attenuation of the increase in femoral blood flow during contractions, but importantly there was no effect on capillary recruitment. NOS inhibition attenuated (P < 0.05) the increase in contraction-stimulated skeletal muscle glucose uptake by ~35%, without affecting AMP-activated protein kinase (AMPK) activation.

CONCLUSIONS: NOS inhibition attenuated increases in skeletal muscle glucose uptake during contraction without influencing capillary recruitment, suggesting that NO is critical for part of the normal increase in skeletal muscle fiber glucose uptake during contraction.

Homocysteine concentration, related B vitamins, and betaine in pregnant women recruited to the Seychelles Child Development Study

Background: Both folate and betaine are important predictors of total homocysteine (tHcy) during pregnancy. However, studies to date have only been undertaken in populations with Western dietary patterns.

Objective: We investigated the predictors of tHcy in pregnant women recruited in the Seychelles, a population where access to fortified foods is limited and where women habitually consume diets rich in fish, eggs, rice, and fruit.

Design: Pregnant women (n = 226) provided blood samples at enrollment, at week 28 of gestation, and at delivery. Cord blood was obtained from a subset of participants (n = 135).

Results: As in other studies, maternal tHcy was lower during pregnancy than at delivery, whereas folate and vitamin B-12 status declined significantly to delivery. Despite low maternal folate status at delivery (median: 9.0 nmol/L), with 35% of women in the deficient range (serum folate: <6.8 nmol/L), cord blood folate status (median: 40.2 nmol/L) was similar to concentrations reported in Western populations. Folate was a significant predictor of tHcy at all time points (P < 0.001). In contrast with previous studies, betaine was only a significant predictor of maternal tHcy (P < 0.001) when the essential amino acid methionine was low.

Conclusions: The current study reports 2 important findings. First, fetal requirements for folate are paramount, such that cord blood folate status is maintained, even when maternal status is low. Second, betaine is a significant predictor of tHcy in pregnant women with low serum folate and low serum methionine concentrations.

Blood mineral, trace-element and vitamin concentrations in Huacaya alpacas and Merino sheep grazing the same pasture

We aimed to determine whether the concentration of minerals and trace constituents in blood of Merino sheep and Huacaya alpacas grazing the same pasture differed with species and time of sampling. Blood samples and pasture samples were collected at frequent intervals over a period of 2 years for mineral and trace-nutrient assay. The concentration of the minerals and trace nutrients in the grazed pasture usually met the dietary needs of sheep at maintenance, apart from potassium, sulfur, cobalt and Vitamin E in occasional samples. Restricted maximum likelihood mixed model analysis indicated a significant (P < 0.001) species by month by year interaction for all blood constituents assayed, a significant (P < 0.05) species by coat shade interaction for plasma Vitamin D, E and B12 and a significant (P < 0.001) species by month by Vitamin D interaction for plasma phosphorus concentrations. In general, plasma calcium concentrations were greater in sheep than in alpacas but plasma magnesium concentrations were greater in alpacas than in sheep. There was no consistent difference between the two species in plasma phosphorus concentrations although low values were recorded in individual sheep and alpacas. Plasma Vitamin D concentrations were more responsive to increasing hours of sunlight in alpacas than they were in sheep. Sheep had consistently higher concentrations of plasma copper, zinc and Vitamin B12 and higher concentrations of blood selenium but lower concentrations of plasma selenium and Vitamin A, than did alpacas. No consistent difference was observed between the two species in plasma Vitamin E concentrations.

Dose-dependent effects of docosahexaenoic acid-rich fish oil on erythrocyte docosahexaenoic acid and blood lipid levels

Consumption of long-chain n-3 PUFA, particularly DHA, has been shown to improve cardiovascular risk factors but the intake required to achieve benefits is unclear. We sought to determine the relationship between DHA intake, increases in erythrocyte DHA content and changes in blood lipids. A total of sixty-seven subjects (thirty-six male, thirty-one female, mean age 53 years) with fasting serum TAG ≥ 1·1 mmol/l and BMI>25 kg/m² completed a 12-week, randomized, double-blind, placebo-controlled parallel intervention. Subjects consumed 2, 4 or 6 g/d of DHA-rich fish oil (26 % DHA, 6 % EPA) or a placebo (Sunola oil). Fasting blood lipid concentrations and fatty acid profiles in erythrocyte membranes were assessed at baseline and after 6 and 12 weeks. For every 1 g/d increase in DHA intake, there was a 23 % reduction in TAG (mean baseline concentration 1·9 (sem 0·1) mmol/l), 4·4 % increase in HDL-cholesterol and 7·1 % increase in LDL-cholesterol. Erythrocyte DHA content increased in proportion to the dose of DHA consumed (r 0·72, P < 0·001) and the increase after 12 weeks was linearly related to reductions in TAG (r − 0·38, P < 0·01) and increases in total cholesterol (r 0·39, P < 0·01), LDL-cholesterol (r 0·33, P < 0·01) and HDL-cholesterol (r 0·30, P = 0·02). The close association between incorporation of DHA in erythrocytes and its effects on serum lipids highlights the importance of erythrocyte DHA as an indicator of cardiovascular health status.

Variation in postsampling treatment of avian blood affects ecophysiological interpretations

The fluid component of blood is widely used in ecophysiological investigations, including measures of immune function and stable isotope ecology. After blood collection, delayed separation of blood extracellular fluids from red blood cells is known to affect the concentration of a wide range of biochemical compounds in the resulting fluid, as does prevention of clotting (producing plasma) when compared with blood allowed to clot (producing serum). One challenge when investigating immune function and stable isotope ecology, therefore, is discriminating variation because of the effect of the biological factors of interest from potential methodological artefacts. This study assesses how seven widely used measures of immune function and stable isotope composition respond both to delayed separation of the cellular and fluid components and to the clotting of blood samples from two species of waterfowl. Samples that remained uncentrifuged for up to 12 h did not differ from those centrifuged within 15 min of sampling from the same individuals, indicating that samples from a wide range of field conditions may remain highly comparable. However, the outcome of three of the four immunological assays and two of the three isotopic analyses was highly dependent on the type of fluid, with higher immunological activity and higher relative concentrations of heavy carbon and total nitrogen in plasma compared to serum. Researchers interested in immune function and stable isotope ecology may obtain the most useful results by ensuring that they use a single fluid type in their investigations.

Association between serum concentration of 25-hydroxyvitamin D and the risk of hip arthroplasty for osteoarthritis: result from a prospective cohort study

OBJECTIVES: There is ongoing debate regarding the optimal serum concentrations of 25-hydroxy-vitamin D for musculoskeletal health, including osteoarthritis (OA). The aim of this prospective cohort study was to determine whether serum 25-hydroxy-vitamin D concentrations were associated with the risk of hip arthroplasty for OA. DESIGN: This study examined 9135 participants from the Australian Diabetes, Obesity and Lifestyle Study who had serum 25-hydroxy-vitamin D measured in 1999-2000 and were aged ≥40 years at the commencement of arthroplasty data collection. The incidence of hip arthroplasty for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry. RESULTS: Over an average 9.1 (standard deviation (SD) 2.7) years of follow-up, 201 hip arthroplasties for OA were identified (males n = 90; females n = 111). In males, a one-standard-deviation increase in 25-hydroxy-vitamin D was associated with a 25% increased incidence (HR 1.25, 95% CI 1.02-1.56), with a dose response relationship evident by quartiles of 25-hydroxy-vitamin D concentration (P for trend 0.04). These results were independent of age, body mass index (BMI), ethnicity, smoking status, physical activity, season of blood collection, latitude, hypertension and diabetes, area level disadvantage or after excluding those with extreme low 25-hydroxy-vitamin D concentrations. No significant association was observed in women (HR 1.10, 95% CI 0.87, 1.39). CONCLUSIONS: Increasing serum 25-hydroxy-vitamin D concentrations were associated with an increased risk of hip arthroplasty for OA in males, while no significant association was observed in females. The mechanism for the association warrants further investigation.

Chronic exposure to sub-lethal concentration of a glyphosate-based herbicide alters hormone profiles and affects reproduction of female Jundia (Rhamdia quelen)

This work was carried out to verify the effect of a glyphosate-based herbicide on Jundia hormones (cortisol, 17 beta-estradiol and testosterone), oocyte and swim-up fry production. Earthen ponds containing Jundia females were contaminated with glyphosate (3.6 mg/L); blood samples were collected from eight females from each treatment immediately before, or at 1, 10, 20 30 and 40 days following contamination. A typical post-stress rise in cortisol levels was observed at the 20th and 40th days following exposure to glyphosate. At the 40th day, 17 beta-estradiol was decreased in the exposed females. A similar number of oocytes were stripped out from females from both groups, however, a lower number of viable swim-up fry were obtained from the herbicide exposed females, which also had a higher liver-somatic index (LSI). The results indicate that the presence of glyphosate in water was deleterious to Rhamdia quelen reproduction, altering steroid profiles and egg viability. (c) 2006 Elsevier B.V. All rights reserved.