RESUMEN
Patients affected by COVID-19 present mostly with respiratory symptoms but acute neurological symptoms are also commonly observed. Furthermore, a considerable number of individuals develop persistent and often remitting symptoms months after infection, characterizing the condition called long-COVID. Since the pathophysiology of acute and persistent neurological manifestations is not fully established, we evaluated the expression of different genes in hippocampal slices of aged rats exposed to the serum of a post-COVID (sPC) individual and to the serum of patients infected by SARS-CoV-2 [Zeta (sZeta) and Gamma (sGamma) variants]. The expression of proteins related to inflammatory process, redox homeostasis, mitochondrial quality control and glial reactivity was determined. Our data show that the exposure to sPC, sZeta and sGamma differentially altered the mRNA levels of most inflammatory proteins and reduced those of antioxidant response markers in rat hippocampus. Furthermore, a decrease in the expression of mitochondrial biogenesis genes was induced by all serum samples, whereas a reduction in mitochondrial dynamics was only caused by sPC. Regarding the glial reactivity, S100B expression was modified by sPC and sZeta. These findings demonstrate that changes in the inflammatory response and a reduction of mitochondrial biogenesis and dynamics may contribute to the neurological damage observed in COVID-19 patients.
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COVID-19 , Humanos , Animales , Ratas , COVID-19/genética , Enfermedades Neuroinflamatorias , Síndrome Post Agudo de COVID-19 , SARS-CoV-2 , Homeostasis , HipocampoRESUMEN
The hypothalamic-pituitary-adrenal (HPA) axis is an important hormonal mechanism of the human body and is extremely programmable during embryonic and fetal development. Analyzing its development in this period is the key to understanding in fact how vulnerabilities of congenital diseases occur and any other changes in the phenotypic and histophysiological aspects of the fetus. The environment in which the mother is exposed during the gestational period can influence this axis. Knowing this, our objective was to analyze in recent research the possible impact of epigenetic programming on the HPA axis and its consequences for fetal development. This review brought together articles from two databases: ScienceDirect and PUBMED researched based on key words such as "epigenetics, HPA axis, cardiovascular disease, and circulatory problems" where it demonstrated full relevance in experimental and scientific settings. A total of 101 articles were selected following the criteria established by the researchers. Thus, it was possible to verify that the development of the HPA axis is directly related to changes that occur in the cardiovascular system, to the cerebral growth and other systems depending on the influence that it receives in the period of fetal formation.
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Epigénesis Genética , Desarrollo Fetal/genética , Sistema Hipotálamo-Hipofisario/metabolismo , Sistema Hipófiso-Suprarrenal/metabolismo , Animales , Biomarcadores , Diferenciación Celular , Femenino , Regulación del Desarrollo de la Expresión Génica , Glucocorticoides/metabolismo , Humanos , Sistema Hipotálamo-Hipofisario/embriología , Intercambio Materno-Fetal , Organogénesis , Sistema Hipófiso-Suprarrenal/embriología , Placenta/metabolismo , EmbarazoRESUMEN
Knowledge of the reproducibility of oral fat tolerance tests is important for experimental design and data interpretation. In this study, seven normolipidaemic men underwent two fat tolerance tests (blood taken fasting and for six hours after a meal containing 1.2 g fat, 1.2 g carbohydrate per kg body mass) with an interval of one week. Eleven normolipidaemic women underwent two fat tolerance tests--one during the follicular phase of the menstrual cycle, the other during the mid-luteal phase. Dietary intake was controlled for two days and subjects refrained from exercise for three days before each test. There was no significant difference in postprandial triglyceride responses between the two tests in the men (10.20 +/- 3.45 mmol/l.h vs. 9.68 +/- 2.77 mmol/l.h, NS) (mean +/- SD); intraclass correlation coefficient between the two tests was 0.93, and within-subject coefficient of variation was 10.1 %. In the women, the postprandial triglyceride response was lower in the luteal phase (6.75 +/- 1.83 mmol/l.h) than in the follicular phase (8.36 +/- 3.71 mmol/l.h) (p = 0.05), intraclass correlation was 0.65 and within-subject coefficient of variation was 23.2 %. These results suggest that, with adequate control of preceding lifestyle, reproducibility of postprandial triglyceride responses is high in men, but menstrual phase should be taken into consideration when studying these responses in women.
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Glucemia/análisis , Grasas/administración & dosificación , Fase Luteínica/sangre , Triglicéridos/sangre , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los ResultadosRESUMEN
OBJECTIVE: A low-fat, high-carbohydrate diet (
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Dieta , Ejercicio Físico/fisiología , Leptina/sangre , Análisis de Varianza , Glucemia/metabolismo , Índice de Masa Corporal , Dieta Reductora , Carbohidratos de la Dieta/administración & dosificación , Carbohidratos de la Dieta/metabolismo , Ayuno/metabolismo , Femenino , Humanos , Insulina/metabolismo , Persona de Mediana Edad , Periodo Posprandial/fisiologíaRESUMEN
BACKGROUND: Infection with bacteria such as Pseudomonas is common in lung allograft recipients, particularly during chronic rejection. Analysis of sputum samples from patients with cystic fibrosis infected with Pseudomonas aeruginosa or Burkholderia cepacia has indicated the presence of bacterial N-acylhomoserine lactones (AHLs) quorum sensing signalling molecules. AHLs not only control the expression of bacterial virulence genes but are also involved in stimulating the maturation of antibiotic resistant biofilms and host chemokine release. It was hypothesised that AHLs may be detected even in clinically stable lung transplant recipients free of clinical infection or rejection. METHODS: Three 60 ml samples of bronchoalveolar lavage (BAL) fluid were taken from nine stable lung transplant recipients 3-12 months after transplantation. Detection of AHLs was carried out on dichloromethane extracted supernatants using the bioluminescence based AHL reporter plasmid pSB1075. This responds to the presence of AHLs with long acyl chains (C10-C14), generating light. Synthetic AHLs were included as positive controls. RESULTS: Five of the nine BAL fluid supernatants exhibited AHL activity, suggesting the presence of AHLs with long N-acyl chains. There was no correlation between the levels of AHLs detected or their absence and BAL fluid microbiology or diagnosis before transplantation. CONCLUSIONS: This is the first evidence for the presence of AHL quorum sensing signals in human lung allograft recipients, even in subjects with no rejection or apparent infection. Further longitudinal follow up of these preliminary findings is required to elucidate potential links with infection, rejection, and allograft deterioration.
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Líquido del Lavado Bronquioalveolar/química , Fibrosis Quística/microbiología , Ligasas/análisis , Trasplante de Pulmón , Infecciones por Burkholderia/complicaciones , Fibrosis Quística/cirugía , Humanos , Infecciones por Pseudomonas/complicaciones , Esputo/microbiología , Trasplante HomólogoRESUMEN
We tested the hypothesis that daily aerobic exercise opposes the fasting hypertriglyceridemia and exaggerated postprandial lipemia observed after substituting dietary fat with carbohydrate. Eight healthy postmenopausal women aged 51 to 66 years consumed the same high-fat mixed meal on 3 occasions: (1) after 3 days on a low-carbohydrate diet (35%, 50%, and 15% energy from carbohydrate, fat, and protein, respectively); (2) after 3 days on an isoenergetic high-carbohydrate diet (corresponding values 70%, 15%, and 15%); and (3) after 3 days on the same high-carbohydrate diet with 60 minutes of brisk walking daily. Plasma triglycerides were higher after the high-carbohydrate diet than after the low-carbohydrate diet: fasting, 1.58+/-0.19 versus 0.96+/-0.12 mmol/L, respectively; 6-hour postprandial area under concentration versus time curve, 13.74+/-1.57 versus 10.12+/-1.15 (mmol/L)xhour, respectively (both P<0.01). In the fasted and postprandial states, concentrations of apolipoproteins B-48 and B-100 in the triglyceride-rich lipoprotein fraction were significantly higher after the high-carbohydrate diet, as was the concentration of remnant-like lipoprotein particle cholesterol (a measure of lipoprotein remnants). These carbohydrate-induced increases in the number of circulating triglyceride-rich particles and their remnants were abolished when subjects had exercised daily during the high-carbohydrate diet.
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Carbohidratos de la Dieta/administración & dosificación , Ejercicio Físico , Lipoproteínas/metabolismo , Triglicéridos/metabolismo , Ácido 3-Hidroxibutírico/sangre , Anciano , Apolipoproteína B-100 , Apolipoproteína B-48 , Apolipoproteínas B/metabolismo , Área Bajo la Curva , Femenino , Humanos , Insulina/sangre , Cinética , Lipoproteínas/sangre , Persona de Mediana Edad , Periodo Posprandial , Triglicéridos/sangreRESUMEN
Regular walking is associated with reduced risk of fracture and, in our recent randomized trial, reduced calcaneal bone loss relative to controls. The present follow-up study compared the effects on dual-energy X-ray absorptiometry, ultrasound and biochemical indices of bone density and metabolism of (i) taking up (ii) continuing with and (iii) ceasing brisk walking for exercise. Subjects were 68 postmenopausal women aged 60-70 years. Twenty previously sedentary women remained sedentary (Sed/Sed) whilst 17 took up brisk walking (Sed/Walk). Fifteen women who had been walking regularly for 1 year returned to their former sedentary lifestyle (Walk/Sed), whilst 16 continued brisk walking over a second year (Walk/Walk). Bone mineral density (BMD), broadband ultrasonic attenuation (BUA), and biochemical markers of bone formation (serum osteocalcin, C-terminal propeptide of type I collagen and bone alkaline phosphatase) and resorption (urinary deoxypyridinoline) were assessed at baseline and 12 months. Women in the Sed/Walk and Walk/Walk groups completed a mean (SEM) of 16.9 (0.7) and 20.8 (1.2) min of brisk walking per day, respectively. Changes in BMD did not differ significantly between groups. Calcaneal BMD decreased significantly in Walk/Sed women [by 2.7 (1.4)%; p = 0.01] whilst changes in other groups were not significant. Calcaneal BUA increased significantly (p = 0.02) in Sed/Walk women [by 7.4 (3.3)%] relative to other groups. Urinary deoxypyridinoline increased over the year in the Sed/Sed group but there were no significant changes in biochemical markers in other groups. Women taking up brisk walking for exercise showed no change in BMD but a significant increase in calcaneal BUA. There was no significant effect on BMD or BUA of continuing brisk walking but calcaneal BMD declined on ceasing brisk walking. Bone resorption increased in sedentary women but not exercisers, suggesting the effect on exercise on bone in postmenopausal women could be through amelioration of this increased turnover.
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Densidad Ósea/fisiología , Huesos/metabolismo , Posmenopausia/metabolismo , Caminata/fisiología , Absorciometría de Fotón , Anciano , Fosfatasa Alcalina/sangre , Aminoácidos/orina , Análisis de Varianza , Huesos/diagnóstico por imagen , Calcáneo , Ensayo de Inmunoadsorción Enzimática , Femenino , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Osteocalcina/sangre , Fragmentos de Péptidos/sangre , Procolágeno/sangre , UltrasonografíaRESUMEN
There is concern that replacement of dietary fat with carbohydrate may not reduce the overall risk of CHD because this replacement strategy elevates postprandial plasma triacylglycerol (TAG) concentrations. The present study was designed to test the hypothesis that daily exercise can offset the augmented postprandial lipaemia associated with a short-term high-carbohydrate diet. Nine healthy, normolipidaemic men aged 33 (sd 4) years consumed a test meal (g/kg body mass; 1.2 fat, 1.1 carbohydrate, 0.2 protein) on three occasions: after 3 d on a typical Western diet (46, 38 and 16 % energy from carbohydrate, fat and protein respectively); after 3 d on an isoenergetic high-carbohydrate diet (corresponding values: 70, 15 and 15 % energy); after 3 d on the same high-carbohydrate diet with 30 min moderate exercise daily. Fasting plasma TAG concentration was higher after the high-carbohydrate diet (1.15 (se 0.16) mmol/l) than after the Western diet (0.83 (se 0.10) mmol/l; ). Similarly, postprandial lipaemia (6 h total area under plasma TAG concentration v. time curve) was higher after the high-carbohydrate diet (12.54 (se 2.07) mmol/l.h) than after the Western diet (9.30 (se 1.30) mmol/l.h; ). The addition of exercise to the high-carbohydrate diet significantly reduced postprandial lipaemia (9.95 (se 1.94) mmol/l.h; when compared with the high-carbohydrate diet) but not fasting TAG concentration (1.02 (se 0.24) mmol/l). In conclusion, daily exercise prevented the augmentation of postprandial lipaemia attributable to the short-term high-carbohydrate diet and, thus, exercise may be a powerful adjunct to dietary change.
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Carbohidratos de la Dieta/administración & dosificación , Ejercicio Físico/fisiología , Lípidos/sangre , Ácido 3-Hidroxibutírico/sangre , Adulto , Glucemia/análisis , Colesterol/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Ácidos Grasos no Esterificados/sangre , Humanos , Insulina/sangre , Ácido Láctico/sangre , Masculino , Periodo Posprandial , Triglicéridos/sangreRESUMEN
One mechanism by which prior exercise decreases the plasma triacylglycerol (TG) response to dietary fat may involve enhanced clearance of TG-rich lipoproteins. The purpose of the present study was to examine the influence of moderate intensity exercise on postprandial lipemia and muscle lipoprotein lipase (LPL) activity. Eight physically active, normolipidemic men aged 27.0 years (SD 4.2), body mass index 24.5 kg. m(-2) (SD 1.3), participated in 2 oral fat-tolerance tests with different preceding conditions. The afternoon before one test ( approximately 16 hours), subjects cycled for 90 minutes at 62.3% (SD 1.7%) of maximal oxygen uptake. Before the other test, subjects refrained from exercise. Samples of muscle, venous blood, and expired air were obtained in the fasted state. Subjects then consumed a high-fat meal (1.4 g fat, 1.2 g carbohydrate, 0.2 g protein, 73 kJ energy per kg body mass) before further blood and expired air samples were collected until 6 hours. The 6-hour areas under the TG concentration v time curves for plasma and for the chylomicron-rich fraction were lower (P <.05) after exercise (plasma, 7.91 [SE 1.09] v 5.72 [SE 0.47] mmol. L(-1). h; chylomicron-rich fraction, 1.98 [SE 0.51] v 0.92 [SE 0.16] mmol. L(-1). h). Muscle LPL activity was not significantly influenced by prior exercise, but the 4 subjects who had higher muscle LPL activity after exercise also had the most noticeable decreases in postprandial lipemia. The difference in lipemia between trials was inversely related to the difference in LPL activity (rho = -.79, P <.05). In the fasted state and postprandially, carbohydrate oxidation was lower after exercise (P <.05). Thus moderate exercise attenuates postprandial lipemia, possibly by altering muscle LPL activity.
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Ejercicio Físico , Lípidos/sangre , Lipoproteína Lipasa/metabolismo , Músculo Esquelético/metabolismo , Adulto , Glucemia/análisis , Estudios Cruzados , Grasas de la Dieta/metabolismo , Metabolismo Energético , Ácidos Grasos no Esterificados/sangre , Humanos , Insulina/sangre , Masculino , Músculo Esquelético/enzimología , Periodo Posprandial , Factores de Tiempo , Triglicéridos/análisis , Triglicéridos/sangreRESUMEN
Seventy strains of the Burkholderia cepacia complex, which currently comprises six genomic species, were tested for their ability to produce N-acylhomoserine lactone (AHL) signal molecules. Using thin layer chromatography in conjunction with a range of AHL biosensors, we show that most strains primarily produce two AHLs, namely N-octanoylhomoserine lactone (C8-HSL) and N-hexanoylhomoserine lactone (C6-HSL). Furthermore, some strains belonging to B. vietnamiensis (genomovar V) produce additional long chain AHL molecules with acyl chains ranging from C10 to C14. For B. vietnamiensis R-921 the structure of the most abundant long chain AHL was confirmed as N-decanoylhomoserine lactone (C10-HSL) by liquid chromatography-mass spectrometry (LC-MS) in combination with total chemical synthesis. Interestingly, a number of strains, most notably all representatives of B. multivorans (genomovar II), did not produce AHLs at least under the growth conditions used in this study. All strains were also screened for the production of extracellular lipase, chitinase, protease, and siderophores. However, no correlation between the AHL production and the synthesis of these exoproducts was apparent. Southern blot analysis showed that all the B. cepacia complex strains investigated, including the AHL-negative strains, possess genes homologous to the C8-HSL synthase cepI and to cepR, which encodes the cognate receptor protein. The nucleotide sequence of the cepI and cepR genes from one representative strain from each of the six genomovars was determined. Furthermore, the cepI genes from the different genomovars were expressed in Escherichia coli and it is demonstrated that all genes encode functional proteins that direct the synthesis of C8-HSL and C6-HSL. Given that cepI from the B. multivorans strain encodes a functional AHL synthase, yet detectable levels of AHLs were not produced by the wild-type, this suggests that additional regulatory functions may be present in members of this genomovar that negatively affect expression of cepI.
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4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Burkholderia cepacia/metabolismo , Ácidos Grasos/metabolismo , Homoserina/metabolismo , Ligasas , 4-Butirolactona/biosíntesis , 4-Butirolactona/química , Acilación , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Infecciones por Burkholderia/microbiología , Burkholderia cepacia/clasificación , Burkholderia cepacia/genética , Quitinasas/metabolismo , Mapeo Cromosómico , Endopeptidasas/metabolismo , Ácidos Grasos/química , Genes Bacterianos , Homoserina/análogos & derivados , Homoserina/biosíntesis , Homoserina/química , Humanos , Lactonas , Lipasa/metabolismo , Datos de Secuencia Molecular , Señales de Localización Nuclear , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Sideróforos/metabolismoRESUMEN
PURPOSE: To evaluate evidence comparing the influence on health outcomes of different patterns and intensities of exercise with equivalent total energy expenditure. METHODS: A computerized literature search, with searches of the reference lists of papers identified. RESULTS: Studies fell into two categories: 1) comparisons of one continuous session of exercise with several short (> or = 10-min) sessions of the same total duration; and 2) comparisons of a session of moderate/hard exercise with a session of lower intensity but equivalent energy expenditure. Within each category, studies were found for training effects and for acute effects. Category 1: Several small, randomized controlled trials showed that improvements in measures of cardiorespiratory fitness did not differ significantly between training regimens based on long or short sessions. Acute effects of two short sessions on excess postexercise oxygen consumption were reported to be greater than those of one longer session. By contrast, short-term decreases in postprandial triglyceride concentrations were found to be similar with three short or one long session. Category 2: Higher-intensity training was consistently found to elicit greater increases in VO(2max) than lower-intensity training of longer duration. No conclusion could be drawn for any other outcome. A session of hard/moderate exercise may be more likely than to induce short-term negative energy balance than light exercise. Findings on the comparability of sessions of different intensities on blood lipids and glucose/insulin dynamics are conflicting. CONCLUSION: Further research is required before the principle of fractionization can be endorsed with confidence.
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Ejercicio Físico , Estado de Salud , Consumo de Oxígeno , Aptitud Física , Adulto , Anciano , Enfermedad Crónica , Metabolismo Energético , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de TiempoRESUMEN
Vibrio anguillarum, which causes terminal hemorrhagic septicemia in fish, was previously shown to possess a LuxRI-type quorum-sensing system (vanRI) and to produce N-(3-oxodecanoyl)homoserine lactone (3-oxo-C10-HSL). However, a vanI null mutant still activated N-acylhomoserine lactone (AHL) biosensors, indicating the presence of an additional quorum-sensing circuit in V. anguillarum. In this study, we have characterized this second system. Using high-pressure liquid chromatography in conjunction with mass spectrometry and chemical analysis, we identified two additional AHLs as N-hexanoylhomoserine lactone (C6-HSL) and N-(3-hydroxyhexanoyl)homoserine lactone (3-hydroxy-C6-HSL). Quantification of each AHL present in stationary-phase V. anguillarum spent culture supernatants indicated that 3-oxo-C10-HSL, 3-hydroxy-C6-HSL, and C6-HSL are present at approximately 8.5, 9.5, and 0.3 nM, respectively. Furthermore, vanM, the gene responsible for the synthesis of these AHLs, was characterized and shown to be homologous to the luxL and luxM genes, which are required for the production of N-(3-hydroxybutanoyl)homoserine lactone in Vibrio harveyi. However, resequencing of the V. harveyi luxL/luxM junction revealed a sequencing error present in the published sequence, which when corrected resulted in a single open reading frame (termed luxM). Downstream of vanM, we identified a homologue of luxN (vanN) that encodes a hybrid sensor kinase which forms part of a phosphorelay cascade involved in the regulation of bioluminescence in V. harveyi. A mutation in vanM abolished the production of C6-HSL and 3-hydroxy-C6-HSL. In addition, production of 3-oxo-C10-HSL was abolished in the vanM mutant, suggesting that 3-hydroxy-C6-HSL and C6-HSL regulate the production of 3-oxo-C10-HSL via vanRI. However, a vanN mutant displayed a wild-type AHL profile. Neither mutation affected either the production of proteases or virulence in a fish infection model. These data indicate that V. anguillarum possesses a hierarchical quorum sensing system consisting of regulatory elements homologous to those found in both V. fischeri (the LuxRI homologues VanRI) and V. harveyi (the LuxMN homologues, VanMN).
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4-Butirolactona/análogos & derivados , 4-Butirolactona/biosíntesis , Proteínas Bacterianas/genética , Genes Bacterianos , Homoserina/análogos & derivados , Oncorhynchus mykiss/microbiología , Vibrio/genética , 4-Butirolactona/metabolismo , Secuencia de Aminoácidos , Animales , Proteínas Bacterianas/metabolismo , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Clonación Molecular , Escherichia coli/metabolismo , Enfermedades de los Peces/microbiología , Eliminación de Gen , Homoserina/biosíntesis , Homoserina/metabolismo , Lactonas/metabolismo , Espectrometría de Masas , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Sistemas de Lectura Abierta , Reacción en Cadena de la Polimerasa , Homología de Secuencia de Aminoácido , Transducción de Señal , Vibrio/metabolismo , Vibrio/patogenicidad , VirulenciaRESUMEN
Evidence is accumulating that high levels of physical activity are associated with a reduced risk of some cancers. This evidence is most consistent for colon cancer, which is reduced by 40-50% among the most active individuals, compared with the least active. The effect is evident in men and women, and appears to be independent of important confounding factors. However, there may be important interactions with body fatness; a high BMI has been reported to be associated with an increased risk of colon cancer in sedentary men but not in physically-active men. Whilst the evidence on breast cancer is less consistent, case-control studies typically suggest a reduction of 25-30% among the most active women, although several studies have found no effect. Potential mechanisms include systemic influences and others relevant only to site-specific cancers. One unifying hypothesis is that physical inactivity reduces insulin sensitivity, leading to a growth-promotional environment which may facilitate neoplasia. The non-specific immune system may be improved by physical activity, possibly through the summative effects of repeated exercise bouts. Regular exercise, even at a recreational level, probably reduces exposure to oestrogen and thus decreases the risk of breast cancer. Increased colonic peristalsis, and thus reduced bowel transit time, might partly explain the lower risk of colon cancer in active people. Physical activity emerges as one of the few modifiable risk factors for some cancers and, as such, justifies further study.
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Ejercicio Físico , Neoplasias/etiología , Obesidad/fisiopatología , Índice de Masa Corporal , Neoplasias de la Mama/etiología , Neoplasias de la Mama/prevención & control , Neoplasias del Colon/etiología , Neoplasias del Colon/prevención & control , Tránsito Gastrointestinal , Humanos , Neoplasias/prevención & control , Obesidad/complicaciones , Factores de RiesgoRESUMEN
Moderate exercise reduces postprandial triacylglycerol concentrations, which are a risk marker for coronary heart disease. The present study sought to determine the qualitative nature of exercise-induced changes in lipid metabolism and their association (if any) with changes in factor VII activation. Eleven normotriglyceridaemic men, aged 51.7+/-6.1 years (mean+/-S.D.), participated in two oral fat tolerance tests after different pre-conditions: control (no exercise), and exercise (90 min of brisk walking the day before). Venous blood samples were obtained in the fasted state and for 8 h after ingestion of a high-fat meal (1.32 g of fat, 1.36 g of carbohydrate, 0.30 g of protein and 10 mg of [1,1,1-(13)C] tripalmitin x kg(-1) body mass). Prior exercise reduced postprandial plasma triacylglycerol concentrations by 25+/-3% (mean+/-S.E.M.), with lower concentrations in the Svedberg flotation rate (Sf) 20--400 (very-low-density lipoprotein) fraction accounting for 79+/-10% of this reduction. There was no effect on plasma factor VII coagulant activity or on the concentration of the active form of factor VIIa. Prior exercise increased postprandial serum 3-hydroxybutyrate and plasma fatty acid concentrations, decreased serum postprandial insulin concentrations and increased exogenous (8 h (13)C breath excretion of 15.1+/-0.9% of ingested dose compared with 11.9+/-0.8%; P=0.00001) and endogenous postprandial fat oxidation. These data raise the possibility that reduced hepatic secretion of very-low-density lipoprotein plays a role in the attenuation of plasma triacylglycerol concentrations seen after exercise, although it is possible that increased triacylglycerol clearance also contributes to this effect.
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Ejercicio Físico/fisiología , Factor VII/metabolismo , Triglicéridos/sangre , Anciano , Quilomicrones/sangre , Grasas de la Dieta/metabolismo , Metabolismo Energético/fisiología , Prueba de Esfuerzo , Ayuno/sangre , Humanos , Insulina/sangre , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Periodo Posprandial/fisiologíaRESUMEN
Moderate intensity exercise reduces postprandial triacylglycerol (TG) concentrations. We tested whether this reflects increased TG clearance. Eight normotriglyceridaemic men, aged 48.3 +/- 7.3 years (mean +/- SD), performed two oral fat tolerance tests (blood samples taken in the fasted state and for six hours after a high-fat meal containing 1.00 g fat, 0.97 g carbohydrate, 58 kJ energy kg-1 fat-free body mass) and two intravenous fat tolerance tests (blood samples in the fasted state and after a bolus injection of Intralipid, 0.1 g fat kg-1 body mass). The afternoon before one oral and one intravenous test, subjects walked briskly for 90 min; no exercise was performed before the control tests. Prior exercise reduced fasting TG concentration similarly in the oral (16 +/- 7 %) (mean +/- SEM) and intravenous (18 +/- 7 %) tests, and reduced postprandial TG concentrations in the oral test by 18 +/- 6 % (all P < 0.05). However, prior exercise did not increase Intralipid clearance (disappearance curve slopes: control, 4.69 +/- 0.49 % min-1; exercise, 4.85 +/- 0.40 % min-1). These data suggest that mechanisms other than increased TG clearance mediate the lower postprandial TG concentrations seen after moderate exercise.
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Ejercicio Físico/fisiología , Lipoproteínas/sangre , Periodo Posprandial/fisiología , Triglicéridos/sangre , Administración Oral , Grasas de la Dieta/administración & dosificación , Prueba de Esfuerzo , Ayuno , Emulsiones Grasas Intravenosas/administración & dosificación , Ácidos Grasos no Esterificados/sangre , Humanos , Inyecciones Intravenosas , Lípidos/sangre , Masculino , Persona de Mediana Edad , Triglicéridos/farmacocinética , Caminata/fisiologíaRESUMEN
OBJECTIVE: To compare the effects of different patterns of brisk walking on day-long plasma triacylglycerol concentrations in sedentary adults. DESIGN: A three-trial, repeated measures design in which subjects were studied in the fasted state and throughout a day during which they consumed three standardized, mixed meals. On different occasions, subjects undertook no exercise (control), walked briskly for 10 min before each meal (short walks) or walked briskly for 30min before breakfast (long walk). SUBJECTS: Seven postmenopausal sedentary women and three sedentary men aged between 34 and 66y, with body mass index between 24 and 35 kg/m2. MEASUREMENTS: Plasma concentrations of triacylglycerol, non-esterified fatty acids, glucose and insulin, metabolic rate and whole-body substrate oxidation in the fasted state and at hourly intervals for 3 h after each meal. RESULTS: Postprandial plasma triacylglycerol concentrations were lower (P= 0.009) during the walking trials than during the control trial (average values: control 2.08 +/- 0.28 mmol/l; short walks 1.83 +/- 0.22mmol/l; long walk 1.84 +/- 0.22mmol/l (mean+/-s.e.) but did not differ between the two patterns of walking. The difference between control and walking trials increased as successive meals were consumed (interaction of trial x meal P= 0.03). Plasma triacylglycerol concentration increased during the 3 h after breakfast, changed little after lunch and decreased after the evening meal (interaction of meal x time P=0.001). When both walking trials were treated as one condition, walking increased postprandial fat oxidation (average values: control, 0.066 +/- 0.009 g/min;walking 0.074 +/- 0.008 g/min; P < 0.01). CONCLUSIONS: Thirty minutes of brisk walking, undertaken in one session or accumulated throughout a day, reduces postprandial plasma triacylglycerol concentrations and increases fat oxidation.
Asunto(s)
Enfermedades Cardiovasculares/prevención & control , Ejercicio Físico/fisiología , Periodo Posprandial , Triglicéridos/sangre , Caminata/fisiología , Adulto , Anciano , Estudios Cruzados , Dieta , Femenino , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno , Factores de TiempoRESUMEN
This study compared the postprandial triacylglycerol (TAG) response to a high-fat meal in trained and untrained normolipidemic young adults after 2 days' abstinence from exercise. Fifty-three subjects (11 endurance-trained men, 9 endurance-trained women, 10 sprint/strength-trained men, 11 untrained men, 11 untrained women) consumed a meal (1.2 g fat, 1.1 g carbohydrate, 66 kJ per kg body mass) after a 12-h fast. Venous blood samples were obtained in the fasted state and at intervals until 6 h. Postprandial responses were the areas under the plasma or serum concentration-vs.-time curves. Neither fasting TAG concentrations nor the postprandial TAG response differed between trained and untrained subjects. The insulinemic response was 29% lower in endurance-trained men than in untrained men [mean difference -37.4 (95% confidence interval -62.9 to -22.9) microIU/ml x h, P = 0.01]. Responses of plasma glucose, serum insulin, and plasma nonesterified fatty acids were all lower for endurance-trained men than for untrained men. These findings suggest that, in young adults, no effect of training on postprandial lipemia can be detected after 60 h without exercise. The effect on postprandial insulinemia may persist for longer.
Asunto(s)
Grasas de la Dieta/sangre , Ejercicio Físico/fisiología , Periodo Posprandial/fisiología , Adolescente , Adulto , Colesterol/sangre , Estudios Transversales , Dieta , Grasas de la Dieta/administración & dosificación , Ayuno/fisiología , Femenino , Humanos , Insulina/sangre , Masculino , Consumo de Oxígeno/fisiología , Carrera/fisiología , Factores Sexuales , Triglicéridos/sangreRESUMEN
Prior exercise decreases postprandial plasma triacylglycerol (TG) concentrations, possibly through changes to skeletal muscle TG extraction. We measured postprandial substrate extraction across the leg in eight normolipidemic men aged 21-46 yr. On the afternoon preceding one trial, subjects ran for 2 h at 64 +/- 1% of maximal oxygen uptake (exercise); before the control trial, subjects had refrained from exercise. Samples of femoral arterial and venous blood were obtained, and leg blood flow was measured in the fasting state and for 6 h after a meal (1.2 g fat, 1.2 g carbohydrate/kg body mass). Prior exercise increased time averaged postprandial TG clearance across the leg (total TG: control, 0.079 +/- 0.014 ml.100 ml tissue(-1).min(-1) ; exercise, 0.158 +/- 0.023 ml.100 ml tissue(-1).min(-1), P <0.01), particularly in the chylomicron fraction, so that absolute TG uptake was maintained despite lower plasma TG concentrations (control, 1.53 +/- 0.13 mmol/l; exercise, 1.01 +/- 0.16 mmol/l, P < 0.001). Prior exercise increased postprandial leg blood flow and glucose uptake (both P < 0.05). Mechanisms other than increased leg TG uptake must account for the effect of prior exercise on postprandial lipemia.
Asunto(s)
Ejercicio Físico/fisiología , Alimentos , Pierna/irrigación sanguínea , Músculo Esquelético/metabolismo , Triglicéridos/sangre , Ácido 3-Hidroxibutírico/sangre , Adulto , Velocidad del Flujo Sanguíneo , Glucemia/metabolismo , Metabolismo Energético , Ácidos Grasos no Esterificados/sangre , Arteria Femoral , Vena Femoral , Humanos , Insulina/sangre , Ácido Láctico/sangre , Masculino , Tasa de Depuración Metabólica , Persona de Mediana Edad , Consumo de Oxígeno , Carrera , Resistencia VascularRESUMEN
Replacement of dietary fat with carbohydrate may not reduce the overall risk of coronary heart disease (CHD), because this elevates plasma triacylglycerol (TAG) concentrations. The lipoproteinemic effects of a high-carbohydrate diet are likely to be more marked shortly after the initiation of such a diet than after longer periods of intervention during which adaptive processes may counteract the initial effects. Therefore, we studied the postprandial responses to a standard meal after 3-day dietary intervention periods. An additional objective was to establish a model for future study of the mechanisms involved. Nine normolipidemic men consumed the meal (1.2 g fat, 1.1 g carbohydrate, and 0.2 g protein per 1 kg body mass) after 3 days on a high-carbohydrate diet (68% +/- 3% energy from carbohydrate, mean +/- SD) and also after 3 days on an isoenergetic high-fat diet (66% +/- 5% energy). Venous blood samples were obtained from fasted subjects and for 6 hours after the meal. In the fasted state, TAG was higher after the high-carbohydrate diet (1.18 +/- 0.18 v0.62 +/- 0.09 mmol/L, mean +/- SEM, P = .02) and high-density lipoprotein (HDL) cholesterol was lower (1.01 +/- 0.08 v 1.10 +/- 0.09 mmol/L, P = .002). The area under the plasma TAG concentration versus time curve was 42% +/- 7% higher after the high-carbohydrate diet (P = .003). After the high-carbohydrate diet, the postprandial insulin response did not differ between trials, but glucose and 3-hydroxybutyrate responses were lower (P = .009 and P = .02, respectively) and the lactate response was higher (P = .001). Plasma nonesterified fatty acids (NEFAs) were lower after the high-carbohydrate diet in the fasted state and for 4 hours postprandially, but were higher thereafter (interaction of time x trial, P = .001). These results indicate that compared with a high-fat diet, the plasma TAG response to a standard high-fat meal is markedly higher after a few days on a high-carbohydrate diet, with major differences in the associated metabolic milieu. The magnitude of these changes and the rapidity with which they developed suggest that this model may be attractive for future studies of the underlying mechanisms.