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Prior studies in younger adults showed that reducing the normally high intake of the saturated fatty acid, palmitic acid (PA), in the North American diet by replacing it with the monounsaturated fatty acid, oleic acid (OA), decreased blood concentrations and secretion by peripheral blood mononuclear cells (PBMCs) of interleukin (IL)-1ß and IL-6 and changed brain activation in regions of the working memory network. We examined the effects of these fatty acid manipulations in the diet of older adults. Ten subjects, aged 65-75 years, participated in a randomized, cross-over trial comparing 1-week high PA versus low PA/high OA diets. We evaluated functional magnetic resonance imaging (fMRI) using an N-back test of working memory and a resting state scan, cytokine secretion by lipopolysaccharide (LPS)-stimulated PBMCs, and plasma cytokine concentrations. During the low PA compared to the high PA diet, we observed increased activation for the 2-back minus 0-back conditions in the right dorsolateral prefrontal cortex (Broadman Area (BA) 9; p < 0.005), but the effect of diet on working memory performance was not significant (p = 0.09). We observed increased connectivity between anterior regions of the salience network during the low PA/high OA diet (p < 0.001). The concentrations of IL-1ß (p = 0.026), IL-8 (p = 0.013), and IL-6 (p = 0.009) in conditioned media from LPS-stimulated PBMCs were lower during the low PA/high OA diet. This study suggests that lowering the dietary intake of PA down-regulated pro-inflammatory cytokine secretion and altered working memory, task-based activation and resting state functional connectivity in older adults.
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Importance: Pediatric obesity is a growing health care burden. Understanding how the metabolic phenotype of youth with obesity may modify the effect of intestinal fermentation on human metabolism is key to designing early intervention. Objective: To assess whether adiposity and insulin resistance in youth may be associated with colonic fermentation of dietary fibers and its production of acetate, gut-derived hormone secretion, and adipose tissue lipolysis. Design, Setting, and Participants: Cross-sectional study of youths aged 15 to 22 years with body mass index in the 25th to 75th percentile or higher than the 85th percentile for age and sex throughout the New Haven County community in Connecticut. Recruitment, studies, and data collection occurred from June 2018 to September 2021. Youths were assigned to a lean, obese insulin sensitive (OIS), or obese insulin resistant (OIR) group. Data were analyzed from April 2022 to September 2022. Exposure: Participants consumed 20 g of lactulose during a continuous 10-hour sodium d3-acetate intravenous infusion to measure the rate of appearance of acetate in plasma. Main Outcomes and Measures: Plasma was obtained hourly to measure acetate turnover, peptide tyrosine tyrosine (PYY), ghrelin, active glucagon-like peptide 1 (GLP-1), and free fatty acids (FFA). Results: A total of 44 youths participated in the study (median [IQR] age, 17.5 [16.0-19.3] years; 25 [56.8%] were female; 23 [52.3%] were White). Consequent to lactulose ingestion, there was a reduction of plasma FFA, an improvement of adipose tissue insulin sensitivity index, an increase in colonic acetate synthesis, and an anorexigenic response characterized by an increased plasma concentration of PYY and active GLP-1 and a reduction of ghrelin in the subgroups. Compared with the lean and OIS groups, the OIR group showed a less marked median (IQR) rate of acetate appearance (OIR: 2.00 [-0.86 to 2.69] µmol × kg-1 × min-1; lean: 5.69 [3.04 to 9.77] µmol × kg-1 × min-1; lean vs OIR P = .004; OIS: 2.63 [1.22 to 4.52] µmol × kg-1 × min-1; OIS vs OIR P = .09), a blunted median (IQR) improvement of adipose insulin sensitivity index (OIR: 0.043 [ 0.006 to 0.155]; lean: 0.277 [0.220 to 0.446]; lean vs OIR P = .002; OIS: 0.340 [0.048 to 0.491]; OIS vs OIR P = .08), and a reduced median (IQR) PYY response (OIR: 25.4 [14.8 to 36.4] pg/mL; lean: 51.3 [31.6 to 83.3] pg/mL; lean vs OIR P = .002; OIS: 54.3 [39.3 to 77.2] pg/mL; OIS vs OIR P = .011). Conclusions and Relevance: In this cross-sectional study, lean, OIS, and OIR youth demonstrated different associations between colonic fermentation of indigestible dietary carbohydrates and the metabolic response, with OIR youth showing minimal metabolic modifications as compared with the other 2 groups. Trial Registration: ClinicalTrials.gov Identifier: NCT03454828.
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Resistencia a la Insulina , Obesidad Infantil , Niño , Adolescente , Femenino , Humanos , Masculino , Fermentación , Ghrelina , Estudios Transversales , Lactulosa , Insulina , Insulina Regular Humana , TirosinaRESUMEN
Writing-based psychological interventions have been widely implemented to produce adaptive change, e.g., through self-affirmation (reminding people of their most important values). To maintain the long-term effects of these interventions, we developed a form of intervention boosters-using user-customized computer passwords to convey the therapeutic messages. We examined whether computer passwords could enhance the effect of a self-affirmation intervention on the psychological well-being of sexual minority undergraduate students as they begin university. Participants were randomly assigned to either complete a self-affirmation writing exercise and create a self-affirming computer password to use for 6 weeks or complete a control writing exercise and create a control computer password. We found that frequency of password usage moderated the intervention effect, such that frequent use of self-affirming passwords buffered decreases in psychological well-being over the study period. These findings suggest that passwords can serve as a low-cost, low-burden, and timely booster for writing-based psychological interventions.
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BACKGROUND: In the last few years, there has been a growing interest in the role of gut microbiota in the development of obesity and its complications. OBJECTIVES: In this study, we tested the following hypotheses: 1) lean youth and youth with obesity experience a different capability of their gut microbiota to ferment carbohydrates and produce acetate; and 2) colonic acetate may serve as a substrate for hepatic de novo lipogenesis (DNL). METHODS: Nineteen lean youth [mean ± SE BMI (in kg/m2): 21.8 ± 0.521] and 19 youth with obesity (BMI: 35.7 ± 1.66), ages 15-21 y, frequency-matched by age and sex, underwent a fasting 10-h sodium [d3]-acetate intravenous infusion to determine the rate of appearance of acetate (Raacet) into the peripheral circulation before and after an oral dose of 20 g of lactulose. Pre- and post-lactulose Raacet values were determined at a quasi-steady state and changes between groups were compared using a quantile regression model. Acetate-derived hepatic DNL was measured in 11 subjects (6 youth with obesity) and its association with Raacet was assessed using Spearman correlation. RESULTS: Mean ± SE Raacet was not different before lactulose ingestion between the 2 groups (7.69 ± 1.02 µmol · kg-1 · min-1 in lean youth and 7.40 ± 1.73 µmol · kg-1 · min-1 in youth with obesity, P = 0.343). The increase in mean ± SE Raacet after lactulose ingestion was greater in lean youth than in youth with obesity (14.7 ± 2.33 µmol · kg-1 · min-1 and 9.29 ± 1.44 µmol · kg-1 · min-1, respectively, P = 0.001). DNL correlated with Raacet, calculated as changes from the pre- to the post-lactulose steady state (ρ = 0.621; P = 0.046). CONCLUSIONS: These data suggest that youth with obesity ferment lactulose to a lesser degree than youth without obesity and that colonic acetate serves as a substrate for hepatic DNL.This trial was registered at clinicaltrials.gov as NCT03454828.
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Acetatos , Microbioma Gastrointestinal , Acetatos/metabolismo , Adolescente , Colon/metabolismo , Femenino , Fermentación , Humanos , Masculino , Obesidad/metabolismo , Adulto JovenRESUMEN
BACKGROUND: Pharmacokinetics (PK) of pharmaceuticals and pharmaconutrients are poorly understood in critically ill patients, and dosing is often based on healthy subject data. This might be particularly problematic with enteral medications due to metabolic abnormalities and impaired gastrointestinal tract absorption common in critically ill patients. Utilizing enteral fish oil, this study was undertaken to better understand and define PK of enteral omega-3 fatty acids (eicospentaenoic acid [EPA] and docosahexaenoic acid [DHA]) in critically ill patients with severe sepsis. MATERIALS AND METHODS: Healthy volunteers (n = 15) and mechanically ventilated (MV) adults with severe sepsis (n = 10) were recruited and received 9.75 g EPA and 6.75 g DHA daily in two divided enteral doses of fish oil for 7 days. Volunteers continued their normal diet without other sources of fish oil, and sepsis patients received standard enteral feeding. Blood was collected at frequent intervals during the 14-day study period. Peripheral blood mononuclear cells (PMBCs) and neutrophils were isolated and analyzed for membrane fatty acid (FA) content. Mixed linear models and t-tests were used to analyze changes in FA levels over time and FA levels at individual time points, respectively. PK parameters were obtained based on single compartment models of EPA and DHA kinetics. RESULTS: Healthy volunteers were 41.1 ± 10.3 years; 67% were women. In patients with severe sepsis (55.6 ± 13.4 years, 50% women), acute physiologic and chronic health evaluation (APACHE) II score was 27.2 ± 8.8 at ICU admission and median MV duration was 10.5 days. Serum EPA and DHA were significantly lower in sepsis vs. healthy subjects over time. PBMC EPA concentrations were generally not different between groups over time, while PBMC DHA was higher in sepsis patients. Neutrophil EPA and DHA concentrations were similar between groups. The half-life of EPA in serum and neutrophils was significantly shorter in sepsis patients, whereas other half-life parameters did not vary significantly between healthy volunteers and sepsis patients. CONCLUSIONS: While incorporation of n-3 FAs into PBMC and neutrophil membranes was relatively similar between healthy volunteers and sepsis patients receiving identical high doses of fish oil for one week, serum EPA and DHA were significantly lower in sepsis patients. These findings imply that serum concentrations and EPA and DHA may not be the dominant driver of leukocyte membrane incorporation of EPA and DHA. Furthermore, lower serum EPA and DHA concentrations suggest that either these n-3 FAs were being metabolized rapidly in sepsis patients or that absorption of enteral medications and pharmaconutrients, including fish oil, may be impaired in sepsis patients. If enteral absorption is impaired, doses of enteral medications administered to critically ill patients may be suboptimal.
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Nutrición Enteral/métodos , Ácidos Grasos Omega-3/farmacocinética , Aceites de Pescado/farmacocinética , Sepsis/metabolismo , Adulto , Estudios de Cohortes , Enfermedad Crítica , Ácidos Grasos Omega-3/metabolismo , Femenino , Aceites de Pescado/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
We recently reported that lowering the high, habitual palmitic acid (PA) intake in ovulating women improved insulin sensitivity and both inflammatory and oxidative stress. In vitro studies indicate that PA can activate both cell membrane toll-like receptor-4 and the intracellular nucleotide oligomerization domain-like receptor protein (NLRP3). To gain further insight into the relevance to human metabolic disease of dietary PA, we studied healthy, lean and obese adults enrolled in a randomized, crossover trial comparing 3-week, high-PA (HPA) and low-PA/high-oleic-acid (HOA) diets. After each diet, both hepatic and peripheral insulin sensitivities were measured, and we assessed cytokine concentrations in plasma and in supernatants derived from lipopolysaccharide-stimulated peripheral blood mononuclear cells (PBMCs) as well as proinflammatory gene expression in skeletal muscle. Insulin sensitivity was unaffected by diet. Plasma concentration of tumor necrosis factor-α was higher during the HPA diet. Lowering the habitually high PA intake by feeding the HOA diet resulted in lower secretion of interleukin (IL)-1ß, IL-18, IL-10, and tumor necrosis factor-α by PBMCs, as well as lower relative mRNA expression of cJun and NLRP3 in muscle. Principal components analysis of 156 total variables coupled to analysis of covariance indicated that the mechanistic pathway for the differential dietary effects on PBMCs involved changes in the PA/OA ratio of tissue lipids. Our results indicate that lowering the dietary and tissue lipid PA/OA ratio resulted in lower leukocyte production of proinflammatory cytokines and muscle expression of redox-sensitive genes, but the relevance to diabetes risk is uncertain.
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Dieta , Leucocitos/metabolismo , Lípidos/química , Músculo Esquelético/metabolismo , Ácido Oléico/química , Ácido Palmítico/química , Adolescente , Adulto , Composición Corporal , Estudios Cruzados , Citocinas/sangre , Femenino , Regulación de la Expresión Génica , Humanos , Inmunidad Innata , Inflamación , Resistencia a la Insulina , Interleucina-10/metabolismo , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Leucocitos/citología , Leucocitos Mononucleares/citología , Lípidos/sangre , Masculino , Estrés Oxidativo , ARN Mensajero/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Adulto JovenRESUMEN
Palmitic acid (PA) is associated with higher blood concentrations of medium-chain acylcarnitines (MCACs), and we hypothesized that PA may inhibit progression of FA ß-oxidation. Using a cross-over design, 17 adults were fed high PA (HPA) and low PA/high oleic acid (HOA) diets, each for 3 weeks. The [1-(13)C]PA and [13-(13)C]PA tracers were administered with food in random order with each diet, and we assessed PA oxidation (PA OX) and serum AC concentration to determine whether a higher PA intake promoted incomplete PA OX. Dietary PA was completely oxidized during the HOA diet, but only about 40% was oxidized during the HPA diet. The [13-(13)C]PA/[1-(13)C]PA ratio of PA OX had an approximate value of 1.0 for either diet, but the ratio of the serum concentrations of MCACs to long-chain ACs (LCACs) was significantly higher during the HPA diet. Thus, direct measurement of PA OX did not confirm that the HPA diet caused incomplete PA OX, despite the modest, but statistically significant, increase in the ratio of MCACs to LCACs in blood.
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Carnitina/análogos & derivados , Dieta , Ácidos Grasos/sangre , Palmitatos/administración & dosificación , Adolescente , Adulto , Composición Corporal/efectos de los fármacos , Carnitina/sangre , Citocinas/metabolismo , Grasas de la Dieta/administración & dosificación , Femenino , Humanos , Inmunidad Innata/efectos de los fármacos , Peroxidación de Lípido/genética , Masculino , Ácido Oléico/administración & dosificación , Palmitatos/sangreRESUMEN
This study used mice with muscle-specific overexpression of PGC-1α, a transcriptional coactivator that promotes mitochondrial biogenesis, to determine whether increased oxidative potential facilitates metabolic improvements in response to lifestyle modification. MCK-PGC1α mice and nontransgenic (NT) littermates were fed a high-fat diet (HFD) for 10 weeks, followed by stepwise exposures to voluntary wheel running (HFD+Ex) and then 25% caloric restriction with exercise (Ex/CR), each for an additional 10 weeks with continued HFD. Running and CR improved weight and glucose control similarly in MCK-PGC1α and NT mice. Sedentary MCK-PGC1α mice were more susceptible to diet-induced glucose intolerance, and insulin action measured in isolated skeletal muscles remained lower in the transgenic compared with the NT group, even after Ex/CR. Comprehensive profiling of >200 metabolites and lipid intermediates revealed dramatic group-specific responses to the intervention but did not produce a lead candidate that tracked with changes in glucose tolerance irrespective of genotype. Instead, principal components analysis identified a chemically diverse metabolite cluster that correlated with multiple measures of insulin responsiveness. These findings challenge the notion that increased oxidative capacity defends whole-body energy homeostasis and suggest that the interplay between mitochondrial performance, lipotoxicity, and insulin action is more complex than previously proposed.
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Restricción Calórica , Músculo Esquelético/metabolismo , Condicionamiento Físico Animal , Factores de Transcripción/metabolismo , Animales , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/efectos adversos , Metabolismo Energético , Regulación de la Expresión Génica , Masculino , Ratones , Mitocondrias Musculares/metabolismo , Actividad Motora , Oxidación-Reducción , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Proteómica , Factores de Transcripción/genéticaRESUMEN
BACKGROUND: Epidemiologic evidence has suggested that diets with a high ratio of palmitic acid (PA) to oleic acid (OA) increase risk of cardiovascular disease (CVD). OBJECTIVE: To gain additional insights into the relative effect of dietary fatty acids and their metabolism on CVD risk, we sought to identify a metabolomic signature that tracks with diet-induced changes in blood lipid concentrations and whole-body fat oxidation. DESIGN: We applied comprehensive metabolomic profiling tools to biological specimens collected from 18 healthy adults enrolled in a crossover trial that compared a 3-wk high-palmitic acid (HPA) with a low-palmitic acid and high-oleic acid (HOA) diet. RESULTS: A principal components analysis of the data set including 329 variables measured in 15 subjects in the fasted state identified one factor, the principal components analysis factor in the fasted state (PCF1-Fasted), which was heavily weighted by the PA:OA ratio of serum and muscle lipids, that was affected by diet (P < 0.0001; HPA greater than HOA). One other factor, the additional principal components analysis factor in the fasted state (PCF2-Fasted), reflected a wide range of acylcarnitines and was affected by diet in women only (P = 0.0198; HPA greater than HOA). HOA lowered the ratio of serum low-density lipoprotein to high-density lipoprotein (LDL:HDL) in men and women, and adjustment for the PCF1-Fasted abolished the effect. In women only, adjustment for the PCF2-Fasted eliminated the HOA-diet effect on serum total- and LDL-cholesterol concentrations. The respiratory exchange ratio in the fasted state was lower with the HPA diet (P = 0.04), and the diet effect was eliminated after adjustment for the PCF1-Fasted. The messenger RNA expression of the cholesterol regulatory gene insulin-induced gene-1 was higher with the HOA diet (P = 0.008). CONCLUSIONS: These results suggest that replacing dietary PA with OA reduces the blood LDL concentration and whole-body fat oxidation by modifying the saturation index of circulating and tissue lipids. In women, these effects are also associated with a higher production and accumulation of acylcarnitines, possibly reflecting a shift in fat catabolism.
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Enfermedades Cardiovasculares/etiología , Grasas de la Dieta/efectos adversos , Metabolismo de los Lípidos , Lípidos/sangre , Músculo Esquelético/metabolismo , Ácido Oléico/efectos adversos , Ácido Palmítico/efectos adversos , Adolescente , Adulto , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/metabolismo , Enfermedades Cardiovasculares/prevención & control , Carnitina/análogos & derivados , Carnitina/sangre , Carnitina/metabolismo , Estudios de Cohortes , Estudios Cruzados , Grasas de la Dieta/uso terapéutico , Femenino , Humanos , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Masculino , Proteínas de la Membrana/biosíntesis , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Metabolómica/métodos , Ácido Oléico/uso terapéutico , Factores de Riesgo , Caracteres Sexuales , Regulación hacia Arriba , Vermont/epidemiología , Adulto JovenRESUMEN
Despite the increased availability of strong analgesics and evidence-based recommendations for pain management, under-treatment of cancer-related pain is still common. Extended-release (ER) opioids, in contrast to immediate-release opioids, provide prolonged analgesia. In this review, we aimed to compare the efficacy and safety of ER opioid analgesics in managing moderate-to-severe pain in patients with cancer. We identified randomized controlled trials (RCTs) and controlled observational studies that compared ER opioids in cancer pain by searching several databases, including MEDLINE, EMBASE and the Cochrane Library. Two independent reviewers screened and evaluated retrieved records to select relevant studies. We dually assessed the risk of bias for included studies and evaluated the overall strength of evidence for six critical outcomes using Grading of Recommendations Assessment, Development and Evaluation level of evidence. A total of three double-blind RCTs (comparative efficacy and adverse events), two non-blinded RCTs and four observational studies (comparative adverse events) were included in this review. All randomized trials and one observational study were of high risk of bias, and three observational studies of unclear risk of bias. The level of evidence for the selected efficacy and safety outcomes was low and very low. We synthesized the findings qualitatively because of the paucity of relevant studies as well as variable study design and quality. This systematic review indicates no substantial differences in efficacy and frequent adverse events among ER opioids for cancer pain. The body of evidence, however, is limited to few comparisons and fraught with methodological shortcomings.
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Analgésicos Opioides/administración & dosificación , Analgésicos Opioides/uso terapéutico , Neoplasias/complicaciones , Manejo del Dolor/métodos , Dolor/etiología , Analgésicos Opioides/efectos adversos , Preparaciones de Acción Retardada , Humanos , Dolor/psicología , Calidad de VidaRESUMEN
BACKGROUND: The Western diet increases risk of metabolic disease. OBJECTIVE: We determined whether lowering the ratio of saturated fatty acids to monounsaturated fatty acids in the Western diet would affect physical activity and energy expenditure. DESIGN: With the use of a balanced design, 2 cohorts of 18 and 14 young adults were enrolled in separate randomized, double-masked, crossover trials that compared a 3-wk high-palmitic acid diet (HPA; similar to the Western diet fat composition) to a low-palmitic acid and high-oleic acid diet (HOA; similar to the Mediterranean diet fat composition). All foods were provided by the investigators, and the palmitic acid (PA):oleic acid (OA) ratio was manipulated by adding different oil blends to the same foods. In both cohorts, we assessed physical activity (monitored continuously by using accelerometry) and resting energy expenditure (REE). To gain insight into a possible mood disturbance that might explain changes in physical activity, the Profile of Mood States (POMS) was administered in cohort 2. RESULTS: Physical activity was higher during the HOA than during the HPA in 15 of 17 subjects in cohort 1 (P = 0.008) (mean: 12% higher; P = 0.003) and in 12 of 12 subjects in the second, confirmatory cohort (P = 0.005) (mean: 15% higher; P = 0.003). When the HOA was compared with the HPA, REE measured during the fed state was 3% higher for cohort 1 (P < 0.01), and REE was 4.5% higher in the fasted state for cohort 2 (P = 0.04). POMS testing showed that the anger-hostility score was significantly higher during the HPA (P = 0.007). CONCLUSIONS: The replacement of dietary PA with OA was associated with increased physical activity and REE and less anger. Besides presumed effects on mitochondrial function (increased REE), the dietary PA:OA ratio appears to affect behavior. The second cohort was derived from a study that was registered at clinicaltrials.gov as R01DK082803.
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Afecto/efectos de los fármacos , Metabolismo Basal/efectos de los fármacos , Grasas de la Dieta/farmacología , Ejercicio Físico , Ácidos Grasos/farmacología , Ácido Oléico/farmacología , Ácido Palmítico/farmacología , Adulto , Ira/efectos de los fármacos , Estudios Cruzados , Dieta Mediterránea , Método Doble Ciego , Ayuno , Hostilidad , Humanos , Adulto JovenRESUMEN
Intramuscular accumulation of triacylglycerol, in the form of lipid droplets (LD), has gained widespread attention as a hallmark of metabolic disease and insulin resistance. Paradoxically, LDs also amass in muscles of highly trained endurance athletes who are exquisitely insulin sensitive. Understanding the molecular mechanisms that mediate the expansion and appropriate metabolic control of LDs in the context of habitual physical activity could lead to new therapeutic opportunities. Herein, we show that acute exercise elicits robust upregulation of a broad program of genes involved in regulating LD assembly, morphology, localization, and mobilization. Prominent among these was perilipin-5, a scaffolding protein that affects the spatial and metabolic interactions between LD and their surrounding mitochondrial reticulum. Studies in transgenic mice and primary human skeletal myocytes established a key role for the exercise-responsive transcriptional coactivator PGC-1α in coordinating intramuscular LD programming with mitochondrial remodeling. Moreover, translational studies comparing physically active versus inactive humans identified a remarkably strong association between expression of intramuscular LD genes and enhanced insulin action in exercise-trained subjects. These results reveal an intimate molecular connection between intramuscular LD biology and mitochondrial metabolism that could prove relevant to the etiology and treatment of insulin resistance and other disorders of lipid imbalance.
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Ejercicio Físico , Proteínas de Choque Térmico/metabolismo , Metabolismo de los Lípidos , Músculo Esquelético/citología , Orgánulos/metabolismo , Condicionamiento Físico Animal , Transactivadores/metabolismo , Factores de Transcripción/metabolismo , Animales , Femenino , Regulación de la Expresión Génica , Proteínas de Choque Térmico/genética , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Mitocondrias/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiología , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Transactivadores/genética , Factores de Transcripción/genética , Triglicéridos/metabolismo , Adulto JovenRESUMEN
Relative to diets enriched in palmitic acid (PA), diets rich in oleic acid (OA) are associated with reduced risk of type 2 diabetes. To gain insight into mechanisms underlying these observations, we applied comprehensive lipidomic profiling to specimens collected from healthy adults enrolled in a randomized, crossover trial comparing a high-PA diet to a low-PA/high-OA (HOA) diet. Effects on insulin sensitivity (SI) and disposition index (DI) were assessed by intravenous glucose tolerance testing. In women, but not men, SI and DI were higher during HOA. The effect of HOA on SI correlated positively with physical fitness upon enrollment. Principal components analysis of either fasted or fed-state metabolites identified one factor affected by diet and heavily weighted by the PA/OA ratio of serum and muscle lipids. In women, this factor correlated inversely with SI in the fasted and fed states. Medium-chain acylcarnitines emerged as strong negative correlates of SI, and the HOA diet was accompanied by lower serum and muscle ceramide concentrations and reductions in molecular biomarkers of inflammatory and oxidative stress. This study provides evidence that the dietary PA/OA ratio impacts diabetes risk in women.
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Grasas de la Dieta/administración & dosificación , Resistencia a la Insulina , Metabolismo de los Lípidos/fisiología , Ácido Oléico/administración & dosificación , Ácido Palmítico/administración & dosificación , Adolescente , Adulto , Envejecimiento/fisiología , Composición Corporal , Estudios de Cohortes , Estudios Cruzados , Dieta/efectos adversos , Grasas de la Dieta/clasificación , Grasas de la Dieta/metabolismo , Femenino , Análisis de los Alimentos , Humanos , Masculino , Actividad Motora , Ácido Oléico/química , Ácido Palmítico/química , Aptitud Física , Factores Sexuales , Adulto JovenRESUMEN
OBJECTIVE: Adipocyte infiltration of the musculoskeletal system is well recognized as a hallmark of aging, obesity, and type 2 diabetes. Intermuscular adipocytes might serve as a benign storage site for surplus lipid or play a role in disrupting energy homeostasis as a result of dysregulated lipolysis or secretion of proinflammatory cytokines. This investigation sought to understand the net impact of local adipocytes on skeletal myocyte metabolism. RESEARCH DESIGN AND METHODS: Interactions between these two tissues were modeled using a coculture system composed of primary human adipocytes and human skeletal myotubes derived from lean or obese donors. Metabolic analysis of myocytes was performed after coculture with lipolytically silent or activated adipocytes and included transcript and metabolite profiling along with assessment of substrate selection and insulin action. RESULTS: Cocultured adipocytes increased myotube mRNA expression of genes involved in oxidative metabolism, regardless of the donor and degree of lipolytic activity. Adipocytes in the basal state sequestered free fatty acids, thereby forcing neighboring myotubes to rely more heavily on glucose fuel. Under this condition, insulin action was enhanced in myotubes from lean but not obese donors. In contrast, when exposed to lipolytically active adipocytes, cocultured myotubes shifted substrate use in favor of fatty acids, which was accompanied by intracellular accumulation of triacylglycerol and even-chain acylcarnitines, decreased glucose oxidation, and modest attenuation of insulin signaling. CONCLUSIONS: The effects of cocultured adipocytes on myocyte substrate selection and insulin action depended on the metabolic state of the system. These findings are relevant to understanding the metabolic consequences of intermuscular adipogenesis.
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Adipocitos/metabolismo , Lipólisis , Fibras Musculares Esqueléticas/metabolismo , Carnitina/análogos & derivados , Carnitina/metabolismo , Técnicas de Cocultivo , Ácidos Grasos no Esterificados/metabolismo , Femenino , Expresión Génica/efectos de los fármacos , Glucosa/metabolismo , Humanos , Insulina , Resistencia a la Insulina , Fibras Musculares Esqueléticas/efectos de los fármacos , Obesidad/metabolismo , Delgadez/metabolismo , Triglicéridos/metabolismoRESUMEN
In cultured cells, palmitic acid (PA) and oleic acid (OA) confer distinct metabolic effects, yet, unclear, is whether changes in dietary fat intake impact cellular fatty acid (FA) composition. We hypothesized that short-term increases in dietary PA or OA would result in corresponding changes in the FA composition of skeletal muscle diacylglycerol (DAG) and triacylglycerol (TAG) and/or the specific FA selected for ß-oxidation. Healthy males (N = 12) and females (N = 12) ingested a low-PA diet for 7 days. After fasting measurements of the serum acylcarnitine (AC) profile, subjects were randomized to either high-PA (HI PA) or low-PA/high-OA (HI OA) diets. After 7 days, the fasting AC measurement was repeated and a muscle/fat biopsy obtained. FA composition of intramyocellular DAG and TAG and serum AC was measured. HI PA increased, whereas HI OA decreased, serum concentration of 16:0 AC (P < 0.001). HI OA increased 18:1 AC (P = 0.005). HI PA was associated with a higher PA/OA ratio in muscle DAG and TAG (DAG: 1.03 ± 0.24 vs. 0.46 ± 0.08, P = 0.04; TAG: 0.63 ± 0.07 vs. 0.41 ± 0.03, P = 0.01). The PA concentration in the adipose tissue DAG (µg/mg adipose tissue) was 0.17 ± 0.02 in those receiving the HI PA diet (n = 6), compared to 0.11 ± 0.02 in the HI OA group (n = 4) (P = 0.067). The relative PA concentration in muscle DAG and TAG and the serum palmitoylcarnitine concentration was higher in those fed the high-PA diet.
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Tejido Adiposo/metabolismo , Carnitina/análogos & derivados , Músculo Esquelético/metabolismo , Ácido Oléico/farmacología , Ácido Palmítico/farmacología , Tejido Adiposo/química , Tejido Adiposo/efectos de los fármacos , Carnitina/sangre , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino , Músculo Esquelético/anatomía & histología , Músculo Esquelético/efectos de los fármacos , Ácido Oléico/administración & dosificación , Oxidación-Reducción , Ácido Palmítico/administración & dosificación , Triglicéridos/metabolismoRESUMEN
BACKGROUND: Cecal or distal colonic concentration of butyrate has been used as an index of butyrate production from various fermentable carbohydrates. However, we previously found that cecal concentration of butyrate does not correlate with the rate of synthesis of butyrate in the cecal lumen. As part of a larger study of the cellular effects of cecal infusions of butyrate, we sought to rule out the null hypothesis that cecal infusion of butyrate also would not alter butyrate concentration in the cecum. METHODS: Piglets (n = 10) were fed sow milk replacement formula plus inulin (3 g x L(-1)). After 6 days of oral feeding, the piglets were randomly assigned into 2 equal groups: (I) Cecal infusion of phosphate-buffered NaCl and (II) cecal infusion of butyrate (2.13 micromol x kg(-1) x min(-1)). The concentration of butyrate was measured by gas chromatography in the cecum and distal colon. RESULTS: There was no effect of cecal butyrate infusion on butyrate concentration (mM; I vs II) in the cecum (5.7 +/- 0.4 vs 5.3 +/- 1.1) or distal colon (3.3 +/- 0.6 vs 4.1 +/- 0.8) or on the ratio of cecal butyrate concentration to the sum of the concentrations of butyrate, acetate, propionate, and valerate (0.101 +/- 0.004 vs 0.083 +/- 0.011). There was no effect of cecal butyrate infusion on the concentration of any of these short chain fatty acids. CONCLUSIONS: At an entry rate into the cecum within the physiological range, butyrate had no effect on cecal or distal colonic luminal concentration of butyrate.
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Butiratos/administración & dosificación , Butiratos/metabolismo , Ciego/metabolismo , Fermentación , Inulina/administración & dosificación , Administración Oral , Animales , Animales Recién Nacidos , Butiratos/análisis , Cromatografía de Gases , Inulina/metabolismo , Distribución Aleatoria , PorcinosRESUMEN
OBJECTIVE: Because estrogen and testosterone affect transcription factors regulating mitochondrial function, we assessed the effects of gender on the metabolic response to dietary palmitic acid (PA) vs. oleic acid (OA) in subjects participating in a previously described trial. METHODS AND PROCEDURES: Adults (N = 43) were studied after following a baseline diet (PA = 8.4% kcal, OA = 13.1% kcal) and after undergoing one of two experimental diets: high PA (HI PA) (PA = 16.8%, OA = 16.4% kcal) (N = 21; 11 men) or high OA (HI OA) (PA = 1.7%, and OA = 31.4%) (N = 22; 11 men). RESULTS: Relative to baseline, the rate of fatty acid (FA) oxidation (% resting energy expenditure(REE)) (mean +/- s.e.m.) increased in women on HI OA while decreasing on HI PA in the fed (+11.8 +/- 5.6% vs. -6.3 +/- 4.2%, P = 0.02) and fasting states (+13.4 +/- 4.2% vs. -12.7 +/- 6.9%, P = 0.047), but changes in men were not statistically significant. Daily energy expenditure changed only in men, increasing on HI OA and decreasing on HI PA (+66 +/- 61 kcal/day or 1.2 +/- 1.0 kcal/kg fat-free mass (FFM)/day vs. -266 +/- 78 kcal/day or -4.2 +/- 1.3 kcal/kg FFM/day, P = 0.004 and P = 0.007, respectively). DISCUSSION: Increased dietary PA/OA caused decreased FA oxidation in women, in the fed and fasted states and decreased daily energy expenditure (DEE) in men.
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Metabolismo Energético/efectos de los fármacos , Ácidos Grasos/metabolismo , Ácido Oléico/farmacología , Palmitatos/farmacología , Caracteres Sexuales , Adulto , Composición Corporal/efectos de los fármacos , Grasas de la Dieta/metabolismo , Femenino , Humanos , Lípidos/sangre , Masculino , Oxidación-Reducción/efectos de los fármacosRESUMEN
BACKGROUND: In vitro, butyrate inhibits histone deacetylase and down-regulates expression of cyclin D1. We hypothesized that an increased entry rate of butyrate into the cecal lumen would have similar effects in vivo. METHODS: We used frozen cecal tissue and data from previous studies, one showing that lactulose supplementation caused an increased rate of cecal synthesis of butyrate and decreased cecal cell proliferation and density of clostridia and the other showing that cecal cell proliferation was increased by an exogenous cecal butyrate infusion at a comparable rate. The ratio of acetylated to total histones (AH ratio) and cyclin D1 mRNA expression were measured in cecal tissue. RESULTS: Lactulose supplementation caused a 189% increase in the AH ratio (p = .004), which inversely correlated with cecal cell proliferation (r = -0.782; p = .008). With cecal butyrate infusion, we observed a significant decrease in histone acetylation (p = .02), which also inversely correlated with cecal cell proliferation (r = -0.797; p = .002). Cyclin D1 expression was increased 6.5-fold by lactulose feeding (p = .02) but decreased 50% with cecal butyrate infusion (p = .004). CONCLUSIONS: The effects on histone acetylation of increased "endogenous" butyrate production produced by lactulose feeding, but not exogenous cecal infusion of butyrate, mirror those in vitro. Thus, bacterial production and exogenous infusion of butyrate have opposite effects on histone acetylation and cyclin D1 expression, suggesting that the composition of bacterial flora may play a role in butyrate's in vivo effects on the cell cycle.
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Bacterias/metabolismo , Butiratos/farmacología , Ciego/metabolismo , Ciclina D1/metabolismo , Histonas/metabolismo , Animales , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Fármacos Gastrointestinales/farmacología , Regulación de la Expresión Génica , Inhibidores de Histona Desacetilasas , Histonas/efectos de los fármacos , Lactulosa/farmacología , PorcinosRESUMEN
OBJECTIVE: Using tracers, we showed, over 9 hours, that palmitic acid (PA) is oxidized at a lower rate than oleic acid (OA). Our subsequent clinical trial showed that enriching the diet for 28 days with PA, relative to OA, lowered fatty acid (FA) oxidation. However, because this conclusion was based on indirect calorimetry for 7 hours after a test meal, transient differences in the kinetics of oxidation of OA and PA could explain these results. Thus, we hypothesized that increasing PA vs. OA would decrease FA oxidation during the first day of feeding the diets. RESEARCH METHODS AND PROCEDURES: A double-masked trial was conducted in 20 adults, who, after a baseline diet, were randomized to one of two experimental formula diets: high (HI) OA (PA=1.7% kcal, OA=31.4% kcal; N=11) or HI PA (PA=16.8% kcal, OA=16.4% kcal; N=9). Respiratory quotient (RQ) was measured over the first 14 hours of feeding the experimental diets (7:00 am to 9:00 pm). To determine whether these subjects were representative of the subjects in the previous trial, we assessed RQ 28 days after beginning either diet. RESULTS: During the first 14 hours of feeding the diets, time (p=0.026) but not diet group had an effect on the difference between the RQ post-feeding and the fasting pre-value. However, RQ in the fed state was significantly higher in the HI PA group after 28 days of feeding. DISCUSSION: Chronically increasing dietary PA for 28 days, but not acute meal feeding, lowers total FA oxidation.
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Ingestión de Alimentos , Ácido Oléico/farmacología , Ácido Palmítico/farmacología , Fenómenos Fisiológicos Respiratorios , Adulto , Composición Corporal , Ingestión de Energía , Metabolismo Energético , Humanos , Valores de ReferenciaRESUMEN
BACKGROUND: In order to understand the consequences of persistent enteral feeding in patients with carbohydrate malabsorption, we fed piglets lactulose in sufficient dosage to produce osmotic diarrhea or inulin, using a conventional dose, to determine if this prebiotic can modulate the effects of lactulose. Feeding lactulose increases cecal luminal synthesis of butyrate, with inulin having an intermediate effect. Because clostridia may be a major source of colonic butyrate production, we hypothesized that feeding piglets lactulose or inulin would increase cecal densities of clostridia. METHODS: Piglets were assigned to 3 formula study groups for 6 days: (1) control, fed only sow milk replacer (n = 12); (2) inulin, inulin supplement (3 g/L; n = 11); and (3) lactulose, lactulose supplement (66.7 g/L; n = 6). Cecal fluid for bacteriological studies was sampled intraoperatively. RESULTS: The wet/dry ratio of the cecal contents (mean +/- SEM) was 8.2 +/- 0.5, 6.2 +/- 0.5, and 18.8 +/- 5.5, respectively, in the control, inulin, and lactulose groups (p = .049, Kruskal-Wallis). There were no differences among the diet groups for cecal densities (10(6) colony-forming units [CFU]/g dry wt cecal contents) of total anaerobes, total aerobes, bifidobacteria, or lactobacilli. Densities of clostridia were markedly reduced in the lactulose group (1.14 +/- 0.41) vs the control (18.39 +/- 4.44; p = .001) or inulin groups (8.87 +/- 2.20; p = .04). CONCLUSIONS: In piglets, feeding lactulose at a dose known to cause diarrhea reduces cecal densities of clostridia.