Sickle cell disease is associated with hypermetabolism and a consequent shortage of substrates for normal growth and healthy immune response. The protein:energy ratio is a major determinant of dietary adequacy; the requirement for optimal growth of control mice is 20% of energy from dietary protein. This study investigated the efficacy of increased dietary protein for improving weight gain and reducing inflammation in the Berkeley sickle cell mouse model (S). The study examined the effect of diet on weight gain and circulating levels of 2 inflammatory proteins, C-reactive protein (CRP), and cytokine interleukin-6 (IL-6). Male C57BL/6 (C) control (n = 8) and S mice (n = 8) were randomized at weaning to 40 d of isoenergetic diets containing 20% (normal) and 35% (high) of energy from protein (C20, C35, S20, S35), replacing dextrin. Rate of weight gain was calculated and plasma CRP and IL-6 concentrations determined by ELISA. Liver mRNA expression of these proteins was measured by real-time PCR and L-arginase by colorimetric assay. S35 mice tended to gain weight more rapidly than S20 mice (P = 0.06) and more rapidly than C35 mice (P < 0.01). Circulating CRP and IL-6 levels were also lower in S35 mice than in S20 mice (P < 0.05), as was liver CRP mRNA expression (P < 0.01). These results demonstrate that introducing a high protein diet at weaning attenuates the steady-state inflammation in this S mouse model. Dietary L-arginine availability was investigated as a possible mechanism for increased nitric oxide production and consequent reduced inflammation.
Independently, metformin (MET) and the prebiotic, oligofructose (OFS), have been shown to increase glucagon-like peptide (GLP-1) secretion. Our objective was to determine whether using OFS as an adjunct with MET augments GLP-1 secretion in obese rats. Male, diet-induced obese Sprague Dawley rats were randomized to: 1) high-fat/-sucrose diet [HFHS; control (C); 20% fat, 50% sucrose wt:wt]; 2) HFHS+10% OFS (OFS); 3) HFHS + MET [300 mg/kg/d (MET)]; 4) HFHS+10% OFS+MET (OFS +MET). Body composition, glycemia, satiety hormones, and mechanisms related to dipeptidyl peptidase 4 (DPP4) activity in plasma, hepatic AMP-activated protein kinase (AMPK; Western blots), and gut microbiota (qPCR) were examined. Direct effects of MET and SCFA were examined in human enteroendocrine cells. The interaction between OFS and MET affected fat mass, hepatic TG, secretion of glucose-dependent insulinotropic polypeptide (GIP) and leptin, and AMPKα2 mRNA and phosphorylated acetyl CoA carboxylase (pACC) levels (P < 0.05). Combined, OFS and MET reduced GIP secretion to a greater extent than either treatment alone (P < 0.05). The hepatic pACC level was increased by OFS+MET by at least 50% above all other treatments, which did not differ from each other (P < 0.05). OFS decreased plasma DPP4 activity (P < 0.001). Cecal Bifidobacteria (P < 0.001) were markedly increased and C. leptum decreased (P < 0.001) with OFS consumption. In human enteroendocrine cells, the interaction between MET and SCFA affected GLP-1 secretion (P < 0.04) but was not associated with higher GLP-1 than the highest individual doses. In conclusion, the combined actions of OFS and MET were associated with important interaction effects that have the potential to improve metabolic outcomes associated with obesity.
PMID: 22223580 CAMSID: cams3220
The novel polysaccharide (NPS) PolyGlycopleX (PGX) has been shown to reduce glycemia. Pharmacological treatment with sitagliptin, a dipeptidyl peptidase 4 (DPP4) inhibitor, also reduces glycemia by increasing glucagon-like peptide-1 (GLP-1). Our objective was to determine if using NPS in combination with sitagliptin reduces hyperglycemia in Zucker diabetic fatty (ZDF) rats more so than either treatment alone. Male ZDF rats were randomized to: 1) cellulose/vehicle [control (C)]; 2) NPS (5% wt:wt)/vehicle (NPS); 3) cellulose/sitagliptin [10 mg/(kg · d) (S)]; or 4) NPS (5%) + S [10 mg/(kg · d) (NPS+S)]. Glucose tolerance, adiposity, satiety hormones, and mechanisms related to DPP4 activity and hepatic and pancreatic histology were examined. A clinically relevant reduction in hyperglycemia occurred in the rats treated with NPS+S (P = 0.001) compared with NPS and S alone. Blood glucose, measured weekly in fed and feed-deprived rats and during an oral glucose tolerance test, was lower in the NPS+S group compared with all other groups (all P = 0.001). At wk 6, glycated hemoglobin was lower in the NPS+S group than in the C and S (P = 0.001) and NPS (P = 0.06) groups. PGX (P = 0.001) and S (P = 0.014) contributed to increased lean mass. Active GLP-1 was increased by S (P = 0.001) and GIP was increased by NPS (P = 0.001). Plasma DPP4 activity was lower in the NPS+S and S groups than in the NPS and C groups (P = 0.007). Insulin secretion and β-cell mass was increased with NPS (P < 0.05). NPS alone reduced LDL cholesterol and hepatic steatosis (P < 0.01). Independently, NPS and S improve several metabolic outcomes in ZDF rats, but combined, their ability to markedly reduce glycemia suggests they may be a promising dietary/pharmacological co-therapy for type 2 diabetes management.
PMID: 22915295 CAMSID: cams3204
Because dietary fats provide an important source of energy in the newborn, the efficient digestion of dietary fats is critical to their well-being. Despite the importance of dietary fat digestion, newborns have a deficiency of pancreatic triglyceride lipase, the predominant digestive lipase in adults. The efficient dietary fat digestion in newborns suggests that other lipases must compensate for the lack of pancreatic triglyceride lipase. In this study, we test the hypothesis that breast milk, pancreatic carboxyl ester lipase (CEL), or both contribute to dietary fat digestion in the newborn. To test this hypothesis, we determined the amount and composition of fecal fat in wild-type and CEL-deficient newborns nursed by either wild-type or CEL-deficient dams. We tested all genetic permutations of the nursing pairs. An interaction between the genotype of the dam and of the pup determined the amount of fecal fat (P < 0.001). Fecal fat was highest in CEL-deficient pups nursed by CEL-deficient dams. Furthermore, only the feces from the CEL-deficient pups nursed by CEL-deficient dams contained undigested lipids. Even with increased fecal fats, the CEL-deficient pups had normal weight gain. Our results demonstrate that CEL contributes significantly to dietary triglyceride digestion whether it originates from mother’s milk or pancreatic secretions. However, only the absence of both mother’s milk and pancreatic CEL produces fat maldigestion. The absence of a single CEL source makes no difference in the efficiency of dietary fat absorption.
Folate and vitamin B-12 (B-12) are essential for normal brain development. Few studies have examined the relationship of maternal folate and B-12 status during pregnancy to offspring cognitive function. To test the hypothesis that lower maternal plasma folate and B-12 concentrations and higher plasma homocysteine concentrations during pregnancy, are associated with poorer neurodevelopment, cognitive function was assessed during 2007-2008 among 536 children (aged 9-10 y) from the Mysore Parthenon birth cohort. Maternal folate, B-12 and homocysteine concentrations were measured in stored plasma samples taken at 30±2 wk gestation. The children’s cognitive function was measured using 3 core tests from the Kaufman Assessment Battery and additional tests measuring learning ability, long-term storage/retrieval, attention and concentration, visuo-spatial and verbal abilities. During pregnancy 4% of mothers had low folate concentrations (<7 nmol/L), 42.5% had low B-12 concentrations (<150 pmol/L) and 3% had hyperhomocysteinemia (>10 μmol/L). There was a 0.1-0.2 SD increase in the children’s cognitive scores per SD increase in maternal folate concentration (p<0.001 for all tests). The associations with learning ability and long-term storage/retrieval, visuo-spatial ability, attention and concentration were independent of maternal age, BMI, parity, the parents’ education, socio-economic status, rural/urban residence, religion, the child’s gestational age, birth size, sex and the children’s size, educational level and folate and B-12 concentrations at 9.5 y. There were no consistent associations of maternal B-12 and homocysteine concentrations with childhood cognitive performance.
In this Indian population higher maternal folate, but not vitamin B-12 concentrations during pregnancy, predicted better childhood cognitive ability.
Transcription initiation sites of the asparagine synthetase gene were investigated in human hepatoma cells after amino acid limitation by incubation in amino acid-complete minimal essential medium or medium lacking histidine. Cells incubated in complete minimal essential medium had mRNA transcripts with starting positions spanning across the 69 nucleotides immediately upstream of a previously designated transcription start site (+1), whereas the majority of mRNA transcripts started at nucleotide +1 in cells incubated in histidine-free medium. Similar results were obtained regardless of whether the analysis was by 5′ rapid amplification of cDNA ends or a ribonuclease protection assay. Low ASNS mRNA expression in amino acid-complete medium was associated with the wide range of initiation sites, whereas preferred alignment of the general transcription machinery at nucleotide +1, observed in the amino acid deprived condition, was associated with a concurrent increase in transcription activity. To our knowledge, these results are the first example in a mammalian cell of transcription start selection by nutrient availability.
Low plasma concentrations of vitamin B-12 are common in Indians, possibly due to low dietary intakes of animal-source foods. Weather malabosrption of the vitamin contributes to this has not been investigated. A rise in plasma holotranscobalamin (holo-TC) concentration after a standard dose of oral vitamin B-12 has been proposed as a measure of gastrointestinal absorption in people with normal plasma vitamin B-12 concentrations. We studied 313 individuals (children and parents, 109 families) in the Pune Maternal Nutrition Study. They received 3 doses of 10 μg (n=191) or 2 μg (n=122) of cyanocobalamin at 6 h intervals. A rise in plasma holo-TC of ≥15% and >15 pmol/L above baseline was considered normal vitamin B-12 absorption. The baseline plasma vitamin B-12 was <150 pmol/L in 48% of participants; holo-TC was <35 pmol/L in 98%, and total homocysteine was high in 50% (>10 μmol/L in children and >15 μmol/L in adults). In 10 μg group plasma holo-TC concentration increased by 4.8 -fold from (mean ± SD) 9.3 ± 7.0 pmol/L to 53.8 ± 25.9 pmol/L, and in 2 μg group by 2.2 -fold from 11.1 ± 8.5 pmol/L to 35.7 ± 19.3 pmol/L. Only 10% of participants, mostly fathers, had an increase less than the suggested cut-points. Our results suggest that an increase in plasma holo-TC may be used to assess vitamin B-12 absorption in individuals with low vitamin B-12 status. Because malabsorption is unlikely to be a major reason for the low plasma vitamin B-12 concentrations in this population, increasing dietary vitamin B-12 should improve their status.
Vitamin B-12; cyanocobalamin; holotranscobalamin; absorption; India
This study compared social looking and response to novelty in preschool-aged children (47–68 mo) with or without iron deficiency anemia (IDA). Iron status of the participants from a low-income community in New Delhi, India, was based on venous hemoglobin, mean corpuscular volume, and red cell distribution width. Children’s social looking toward adults, affect, and wary or hesitant behavior in response to novelty were assessed in a semistructured paradigm during an in-home play observation. Affect and behavior were compared as a function of iron status: IDA (n = 74) vs. nonanemic (n = 164). Compared with nonanemic preschoolers, preschoolers with IDA displayed less social looking toward their mothers, moved close to their mothers more quickly, and were slower to display positive affect and touch novel toys for the first time. These results indicate that IDA in the preschool period has affective and behavioral effects similar to those reported for IDA in infancy.
Type 2 diabetes (T2DM) subjects failing diet treatment are characterized by hyperinsulinemia and insulin resistance leading to fasting and postprandial hyperglycemia and hyperlipidemia. Energy is essential for allowing the process of protein synthesis to proceed. Additionally, insulin can stimulate protein synthesis in human muscle. The aims of this study were to determine if poorly controlled T2DM affects postabsorptive muscle protein anabolism, and if the muscle anabolic response to hyperinsulinemia with high energy availability is maintained. Control (n = 6) and T2DM subjects (n = 6) were studied in the postabsorptive state and during an isoenergetic high nutritional energy clamp (relative to postabsorptive state). Muscle protein synthesis and breakdown (nmol · min−1 · 100 g leg muscle−1) were assessed using stable isotope methodology, femoral arterio-venous sampling, muscle biopsies, and a three-pool model to calculate protein turnover. Postabsorptive phenylalanine net balance and whole body rate of appearance (Ra) were not different between groups; however, basal muscle protein breakdown was higher in T2DM (94 ± 9) than in controls (58 ± 12) (P < 0.05) and muscle protein synthesis tended (P = 0.07) to be elevated in T2DM (66 ± 14) compared with controls (39 ± 6). During the clamp, net balance increased, whole body Ra and muscle protein breakdown decreased (P < 0.05), and muscle protein synthesis tended to decrease (P = 0.08) to a similar extent in both groups. We conclude that postabsorptive muscle protein turnover is elevated in poorly controlled T2DM, however, there is no excessive loss of muscle protein because net balance is not different from controls. Moreover, the anabolic response to increased insulin and energy availability is maintained in T2DM.
type 2 diabetes; protein metabolism; muscle protein synthesis; protein turnover
Aging is associated with a progressive loss of muscle mass (sarcopenia), which increases the risks of injury and disability. Although the mechanisms of sarcopenia are not clearly elucidated, age-associated alterations in the muscle anabolic response to nutritional stimuli and a decline in protein intake may be significant contributing factors. The most recent findings regarding the role of nutritional intake on protein metabolism in the elderly will be reviewed. Specifically, aging is associated with changes in the muscle protein metabolism response to a meal, likely due to alterations in the response to endogenous hormones. Nonetheless, the older muscle is still able to respond to amino acids, mainly the essential and BCAAs, which have been shown to acutely stimulate muscle protein synthesis in older individuals. It is likely that this stimulatory effect of essential and BCAA is due to the direct effect of leucine on the initiation of mRNA translation, which is still present in older age, although it appears to be attenuated in aged animals. Recent data suggest that excess leucine may be able to overcome this age-related resistance of muscle proteins to leucine. For this reason, long-term essential amino acid supplementation may be a useful tool for the prevention and treatment of sarcopenia, particularly if excess leucine is provided in the supplement.
aging; amino acids; muscle; sarcopenia; protein metabolism
The relationship between four micronutrient deficiencies (iodine, iron, zinc and vitamin B-12) and children’s cognitive functioning is reviewed. Iodine deficiency during pregnancy has negative and irreversible effects on the developing fetus. Although there is some evidence that postnatal iodine deficiency is associated with cognitive deficits, the findings are controversial. Iron deficiency is widespread and has been associated to cognitive deficits, but the results of prevention trials are inconsistent. Zinc deficiency has been linked with low activity and depressed motor development among the most vulnerable children. Associations with cognitive development are less clear and may be limited to specific neuropsychological processes. Vitamin B-12 deficiency has been associated with cognitive problems among the elderly, but little is known about its effect on children’s cognitive functioning. Rates of vitamin B-12 deficiency are likely to be high because animal products are the only source of vitamin B-12. Although micronutrient deficiencies often co-occur in the context of poverty, little is known about the impact of multiple micronutrient deficiencies on cognitive development. J. Nutr. 133: 3927S–3931S, 2003.
micronutrients; iron; iodine; zinc; vitamin B-12; cognitive development
The role of zinc in children’s cognitive and motor functioning is usually assessed by the response to supplementation in populations thought to be zinc deficient. A review of published zinc-supplementation trials that examined behavior and development identified one trial in fetuses, six trials in infants and toddlers and three trials in school-age children. The three studies that examined activity reported that zinc supplementation was associated with more activity. Of the five studies that examined motor development in infants and toddlers, one found improvements among very low-birth–weight infants, one found improvements in the quality of motor development and three found no impact. Of the four studies that examined mental development in infants and toddlers, three found no impact of zinc supplementation and one found that zinc-supplemented children had lower scores than control children. Among school-age children, one study found no impact of zinc supplementation on cognitive performance and two found a beneficial impact of neuropsychological processes, specifically reasoning. The evidence linking zinc deficiency to children’s cognitive and motor functioning suggests a relationship among the most vulnerable children but lacks a clear consensus, highlighting the need for additional research into the timing of zinc deficiency and the co-occurrence with other micronutrient deficiencies.
zinc; child development; cognitive; motor functioning
Parenting, including nonresponsive feeding styles, has been related to under- or overweight among young children. The relationship between maternal mental health and feeding styles has not been examined. We hypothesized that mothers who report more symptoms of stress, depression, or anxiety report less responsive (e.g. more controlling, indulgent, and uninvolved) feeding styles than mothers who report fewer symptoms of stress, depression, or anxiety. Our analyses included 702 mother-infant pairs from a statewide sample of Special Supplemental Nutrition Program for Women, Infants, and Children mothers. We assessed maternal mental health and feeding styles by a telephone survey. After adjusting for potential confounding variables, maternal stress symptomatology was significantly associated with forceful (β = 0.03; 95% CI = 0.02, 0.05) and uninvolved (OR = 1.4; 95% CI = 1.1, 1.7) feeding style scores, maternal depression symptomatology was significantly associated with forceful (β = 0.03; 95% CI = 0.004, 0.05), indulgent (β = 0.03; 95% CI = 0.004, 0.06), and uninvolved (OR = 1.5; 95% CI = 1.001, 2.2) feeding styles scores, and maternal anxiety symptomatology was significantly related to restrictive (β = 0.11;95% CI = 0.01, 0.21), forceful (β = 0.04;95% CI=0.02, 0.06), and uninvolved (OR = 1.4;95% CI = 1.01, 1.9) feeding style scores. Among mothers who perceived their infant as temperamentally fussy, there was a significant positive relationship between restrictive feeding styles scores and 3 indices of maternal mental health (stress, β = 0.18; 95% CI = 0.07, 0.28; depression, β = 0.21; 95% CI = 0.04, 0.38; and cumulative mental health symptomatology, β = 0.29; 95% CI = 0.10, 0.48). Mothers who report stress, depression, or anxiety symptoms are at risk for nonresponsive feeding styles. These findings provide support for broadening the focus of existing child nutrition programs to include strategies that recognize how issues of maternal mental health can affect feeding styles.
Principal component analysis is a popular method of dietary patterns analysis, but our understanding of its use to describe changes in dietary patterns over time is limited. We assessed the diets of 12,572 non-pregnant women aged 20-34 from Southampton, UK using a food frequency questionnaire, of whom 2,270 and 2,649 became pregnant and provided complete dietary data in early and late pregnancy respectively. Intakes of white bread, breakfast cereals, cakes and biscuits, processed meat, crisps, fruit and fruit juices, sweet spreads, confectionery, hot chocolate drinks, puddings, cream, milk, cheese, full-fat spread, cooking fats and salad oils, red meat and soft drinks increased in pregnancy. Intakes of rice and pasta, liver and kidney, vegetables, nuts, diet cola, tea and coffee, boiled potatoes and crackers decreased in pregnancy. Principal component analysis at each time point produced two consistent dietary patterns, labeled ‘prudent’ and ‘high-energy’. At each time point in pregnancy, and for both the prudent and high-energy patterns, we derived two dietary pattern scores for each woman: a ‘natural’ score, based on the pattern defined at that time point, and an ‘applied’ score, based on the pattern defined before pregnancy. Applied scores are preferred to natural scores to characterize changes in dietary patterns over time because the scale of measurement remains constant. Using applied scores there was a very small mean decrease in prudent diet score in pregnancy, and a very small mean increase in high-energy diet score in late pregnancy, indicating little overall change in dietary patterns in pregnancy.
Diet; Dietary patterns; Pregnancy; Principal component analysis
Iron deficiency anemia affects ∼3 billion people in the 21st century, despite >500 years of medical treatment. Studies show that soybean ferritin, the protein nanocage encasing mineralized iron is a source of nutritional iron but the cellular mechanisms of absorption are unknown. The absorption of iron from soybeans with ferritin in the presence of the endogenous soybean iron chelator phytate, suggests that the mechanism could be different than for reduced ferric or ferrous ions. Here, we investigate a cellular mechanism of iron absorption using recombinant soybean ferritin (SBFn&) and Caco-2 cells grown in bicameral inserts as a model for intestinal cells. Binding, internalization and degradation of exogenous, iron-mineralized SBFn, studied with confocal microscopy and binding of 131I-labeled, iron-mineralized ferritin revealed that: 1- SBFn binds on the apical surface. 2- Binding is saturable, Kd = 7.71 ± 0.88 nmol/L. 3- Internalization of SBFn depended on temperature, concentration and time. 4- Iron inside SBFn rapidly entered the labile iron pool (calcein quenching), and 5- SbFn protein was degraded during the same period that iron entered to the cytosol. SBFn crossed the apical membrane by endocytosis dependent on assembly peptide 2 (AP2) based on sensitivity of 131I-SBFn uptake to hyperosmolarity, acidity and siRNA targeted to the μ2 subunit of AP2, as well as resistance to filipin, a caveolar endocytosis inhibitor. The results support a model of iron absorption from gut ferritin distinct from ion transport and dependent on apical endocytosis followed by mineral dissolution/protein degradation and iron delivery to the cytosolic pool that can function, in part at least to absorb/resorb iron from dietary ferritin/sloughed enterocytes.
iron; intestinal absorption; soybean ferritin; endocytosis; AP2
Flavonoids have anti-inflammatory and antioxidative effects and thus may protect against diabetes. Therefore, we hypothesized that consumption of flavonoids and specific food and beverage sources of flavonoids would be associated with reduced risk of incident diabetes. At baseline (1986), diet (by food frequency questionnaire) and health information were collected from 35,816 postmenopausal women free of diabetes. Self-reported incident diabetes was ascertained 5 times during the study (1987, 1989, 1992, 1997, and 2004). Cox proportional hazards regression was used to calculate hazard ratios for incident diabetes according to categories of total flavonoids and anthocyanidins, flavones, flavanones, flavonols, flavan-3-ol monomers, isoflavones, and proanthocyanidins. Hazard ratios according to intake categories of flavonoid-rich foods and beverages were also calculated (apples, pears, berries, broccoli, bran, citrus, tea, and red wine). Flavonoid consumption was not associated with diabetes risk after multivariable adjustment. Although other flavonoid-rich foods and beverages were not associated, red wine was inversely associated with diabetes. Women who reported drinking red wine ≥1 time/wk had a 16% reduced risk of diabetes than those drinking wine <1 time/wk [HR (95% CI): 0.84 (0.71, 0.99)], with parallel findings for white wine, beer, and liquor. In conclusion, these data do not support a diabetes-protective effect of flavonoids. The suggestive evidence of a protective effect of regular red wine consumption is shared with an inverse association between alcohol drinks in general and diabetes risk and may reflect the effects of nonflavonoid constituents that are common to all alcohol drinks.
Green tea and black tea (BT) contain gallated [(−)-epigallocatechin-3-gallate (EGCG), (−)-epicatechin-3-gallate] and nongallated [(−)-epicatechin, (−)-epigallocatechin (EGC)] tea polyphenols (PP). During BT production, PP undergo oxidation and form larger polymers such as theaflavins (THE) and thearubigins, which contribute to the health benefit of BT. This article gives an overview of the role of chemical characteristics and endogenous metabolism of tea PP and their bioavailability in humans and describes attempts to increase their bioavailability. At pH close to neutral, EGCG and EGC form homo- and heterodimers generating hydrogen peroxide. To confirm the pH instability of EGCG, EGC, and THE in cell culture medium, their anti-proliferative activity was determined in the presence and absence of catalase. The antiproliferative activity in LNCaP prostate cancer cells was decreased when incubated with catalase prior to EGCG, EGC, and THE treatment. In addition, new findings demonstrated that the formation of methyl-EGC increased the stability at neutral pH compared with EGC. Approaches to increase the bioavailability of flavan-3-ols are reviewed, which include the administration of tea in combination with fruit juices, coadministration with piperine, and peracetylation of EGCG. Future intervention studies will need to focus on the bioactivity not only of green tea and BT PP but also of their metabolites and biotransformation products.
A "two-hit" model for non-alcoholic steatohepatitis (NASH) has been proposed in which steatosis constitutes the "first hit" and sensitizes the liver to potential "second hits" resulting in NASH. Oxidative stress is considered a candidate for the "second hit". N-acetylcysteine (NAC), an antioxidant, has been suggested as a dietary therapy for NASH. We examined effects of NAC in a rat total enteral nutrition (TEN) model where NASH develops as the result of overfeeding dietary polyunsaturated fat. Male Sprague-Dawley rats were fed pelleted AIN-93G diets ad libitum or were overfed a 9200 kJ˙ kg−0.75˙d−1 liquid diet containing 70% corn oil with or without 2 g˙ kg−1˙d−1 NAC intragastrically for 65 d. Hepatic steatosis was not influenced by dietary supplementation with NAC; however, the liver pathology score was significantly lower (p≤0.05) and NAC provided partial protection against alanine aminotransferase release (p≤0.05). NAC attenuated increased hepatic oxidative stress (TBARS; p≤0.05); prevented increases in cytochrome P450 2E1 apoprotein and mRNA; and tumor necrosis factor-α (TNF-α) mRNA. A decrease in titers of auto-antibodies against proteins adducted to lipid peroxidation products was observed in the NAC group relative to the 70% corn oil group (p≤0.05). NAC also decreased Picosirius red staining of collagen, a marker of fibrosis. However, markers of hepatic stellate cell activation were unaffected. Using NAC in a TEN model of NASH we have demonstrated that NAC prevents many aspects of NASH progression by decreasing development of oxidative stress and subsequent increases in TNF-α, but is unable to block development of steatosis.
steatosis; oxidative stress; lipid peroxidation; TNF-α; fibrosis
Fetal-neonatal iron deficiency alters hippocampal neuronal morphology, reduces its volume, and is associated with acute and long-term learning impairments. However, neither the effects of early-life iron deficiency anemia on growth, differentiation, and survival of hippocampal neurons nor regulation of the neurotrophic factors that mediate these processes has been investigated. We compared hippocampal expression of neurotrophic factors in male rats made iron deficient (ID) from gestational d 2 to postnatal d (P) 7 to iron-sufficient controls at P7, 15, and 30 with quantitative RT-PCR, Western analysis, and immunohistology. Iron deficiency downregulated brain-derived neurotrophic factor (BDNF) expression in the hippocampus without compensatory upregulation of its specific receptor, tyrosine-receptor kinase B. Consistent with low overall BDNF activity, we found lower expression of early-growth response gene-1 and -2, transcriptional targets of BDNF signaling. Doublecortin expression, a marker of differentiating neurons, was reduced during peak iron deficiency, suggesting impaired neuronal differentiation in the ID hippocampus. In contrast, iron deficiency upregulated hippocampal nerve growth factor, epidermal growth factor, and glial-derived neurotrophic factor accompanied by an increase in neurotrophic receptor p75 expression. Our findings suggest that fetal-neonatal iron deficiency lowers BDNF function and impairs neuronal differentiation in the hippocampus.
Dietary protein is theorized to hold both anabolic effects on bone and demineralizing effects mediated by the diet acid load of sulfate derived from methionine and cysteine. The relative importance of these effects is unknown but relevant to osteoporosis prevention. Post-menopausal women (n=161, mean±SD 67.9±6.0 y) were assessed for areal bone mineral density (aBMD) of lumbar spine (LS) and total hip (TH) using dual X-ray absorptiometry, and dietary intakes of protein, sulfur-containing amino acids and minerals using a USDA multiple-pass 24 h recall. The acidifying influence of the diet was estimated using the ratio of protein / potassium intake, the potential renal acid load (PRAL) and intake of sulfate equivalents from protein. aBMD was regressed onto protein intake, then protein controlled for estimated dietary acid load. A step-down procedure assessed potential confounding influences (weight, age, physical activity and calcium and vitamin D intakes). Protein alone did not predict LS aBMD (P=0.81); however, after accounting for a negative effect of sulfate (β=− 0.28, P<0.01), the direct effect of protein intake was positive (β=0.22, P=0.04). At the TH protein intake predicted aBMD (β=0.18, P=0.03), but R2 did not improve with adjustment for sulfate (P=0.83). PRAL and the protein / potassium ratio were not significant predictors of aBMD. Results suggest that protein intake is positively associated with aBMD, but benefit at the LS is offset by a negative impact of the protein sulfur acid load. If validated experimentally, these findings harmonize conflicting theories on the role of dietary protein in bone health.
bone mineral density; protein; sulfur; diet acid load
Enterolactone, a major metabolite of plant-based lignans, has been shown to inhibit prostate cancer growth and development, but the mechanistic basis for its anticancer activity remains largely unknown. Activation of insulin-like growth factor-1 receptor (IGF-1R) signaling is critical for prostate cancer cell growth and progression. The present study examined whether the growth inhibitory effect of enterolactone was related to changes in the IGF-1/IGF-1R system in PC-3 prostate cancer cells. At nutritionally relevant concentrations (20-60 μmol/L), enterolactone inhibited IGF-1-induced activation of IGF-1R and its downstream AKT and mitogen-activated protein kinase (MAPK)/extracellular-signal regulated kinase (ERK) signaling pathways. Inhibition of AKT by enterolactone resulted in decreased phosphorylation of its downstream targets, including p70S6K1 and glycogen synthase kinase-3 beta (GSK-3 β). Enterolactone also inhibited cyclin D1 expression. As a result, enterolactone inhibited proliferation and migration of PC-3 cells. Knockdown of IGF-1R by si-RNA resulted in inhibition of proliferation of PC-3 cells and no significant differences in the cell numbers were observed when the si-IGF-1R groups (cells transfected with plasmaids containing siRNA against IGF-1R mRNA) were treated with or without enterolactone. These results suggest that enterolactone suppresses proliferation and migration of prostate cancer cells, at least partially, through inhibition of IGF-1/IGF-1R signaling. The finding of this study provides new insights into the molecular mechanisms that enterolactone exerts against prostate cancer.
Previous work done in our laboratory suggested a role for liver fatty acid binding protein (L-FABP) in obesity that develops in aging female L-FABP gene-ablated (−/−) mice. To examine this possibility in more detail, cohorts of wild-type (+/+) and L-FABP (−/−) female mice were fed a standard low-fat nonpurified rodent diet for up to 18 mo. Various obesity-related parameters were examined including body weight and fat and lean tissue mass. Obesity in (−/−) mice was associated with increased expression of nuclear receptors that induce peroxisome proliferator-activated receptor α (PPARα) (e.g., hepatocyte nuclear factor 1α, genotype effectα and of PPARα-regulated proteins involved in uptake of free (lipoprotein lipase and fatty acid transport protein, genotype and/or age effect) and esterified (scavenger receptor class B type 1, genotype effect) long chain fatty acids (LCFAs). Hepatic total lipid and neutral lipid levels were not affected by age or genotype, consistent with absence of gross and histologic steatosis. There was increased mRNA expression of liver proteins involved in LCFA oxidation [mitochondrial 3-oxoacyl-CoA thiolase (genotype effect) and butyryl-CoA dehydrogenase (genotype and/or age effect)], increased expression of LCFA esterification enzymes [glycerol-3-phosphate acyltransferase (age × genotype effect) and acyl-CoA:cholesterol acyltransferase-2 (genotype and/or age effect)], and increased expression of proteins involved in intracellular transfer and secretion of esterified LCFA [liver microsomal triacylglycerol transfer protein (genotype effect), serum apolipoprotein B (genotype or age effect), and liver apolipoprotein B (age and age × genotype effect)]. The data support a working model in which obesity development in these mice results from shifts toward reduced energy expenditure and/or more efficient energy uptake in the gut.
UDP-glucuronosyltransferase (UGT) 1A1 glucuronidates bilirubin, estrogens, and xenobiotic compounds. The UGT1A1*28 polymorphism results in lower promoter activity due to 7 thymine-adenine (TA) repeats, rather than the more common 6 TA repeats. Previously, we showed that serum bilirubin, a marker of UGT1A1 activity, was lower among individuals homozygous for the UGT1A1*28 polymorphism (7/7) when randomized to a high fruit and vegetable (F&V) diet, whereas no effect was seen in individuals with the wild-type (6/6) and heterozygous (6/7) genotypes. Our objective here was to determine if we could detect genotype-diet interactions on bilirubin concentrations in an observational study. Healthy non-smoking men (n=146) and women (n=147), recruited from the Seattle area, provided blood samples for genotyping and bilirubin measurements. We used multiple linear regression to assess the relationships between UGT1A1 genotype, bilirubin concentrations and consumption of specific F&V [cruciferous vegetables, citrus fruits, and soy foods (n=268)] based on FFQ, and F&V from 6 botanical families [Cruciferae, Rosaceae, Rutaceae, Umbelliferae, Solanaceae and Leguminosae (n=261)] based on 3 d food records. We observed a significant interaction of UGT1A1 genotype and citrus consumption among women. Women with the 7/7 genotype who consumed 0.5 or more daily servings of citrus fruit or foods from the Rutaceae botanical family had ~30% lower serum bilirubin than those with the same genotype who consumed less, while 6/6 and 6/7 genotypes did not differ by consumption (P for interaction = 0.006 and 0.03 respectively). These results suggest that citrus consumption may increase UGT1A1 activity among women with the 7/7 genotype.
Biotin affects gene expression through a diverse array of cell signaling pathways. Previous studies provided evidence that cGMP-dependent signaling also depends on biotin, but the mechanistic sequence of cGMP regulation by biotin is unknown. Here we tested the hypothesis that the effects of biotin in cGMP-dependent cell signaling are mediated by nitric oxide (NO). Human lymphoid (Jurkat) cells were cultured in media containing deficient (0.025 nmol/L), physiological (0.25 nmol/L), and pharmacological (10 nmol/L) concentrations of biotin for 5 wk. Both levels of intracellular biotin and NO exhibited a dose-dependent relationship in regard to biotin concentrations in culture media. Effects of biotin on NO levels were disrupted by the NO synthase (NOS) inhibitor N-monomethyl-arginine. Biotin-dependent production of NO was linked with biotin-dependent expression of endothelial and neuronal NOS, but not inducible NOS. Previous studies revealed that NO is an activator of guanylate cyclase. Consistent with these previous observations, biotin-dependent generation of NO increased the abundance of cGMP in Jurkat cells. Finally, the biotin-dependent generation of cGMP increased protein kinase G activity. Collectively this study is consistent with the hypothesis that biotin-dependent cGMP signaling in human lymphoid cells is mediated by NO.
biotin; cGMP; human; Jurkat cells; nitric oxide