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1.
Physiol Genomics ; 54(12): 501-513, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36278270

RESUMO

The ability of individuals with end-stage osteoarthritis (OA) to functionally recover from total joint arthroplasty is highly inconsistent. The molecular mechanisms driving this heterogeneity have yet to be elucidated. Furthermore, OA disproportionately impacts females, suggesting a need for identifying female-specific therapeutic targets. We profiled the skeletal muscle transcriptome in females with end-stage OA (n = 20) undergoing total knee or hip arthroplasty using RNA-Seq. Single-gene differential expression (DE) analyses tested for DE genes between skeletal muscle overlaying the surgical (SX) joint and muscle from the contralateral (CTRL) leg. Network analyses were performed using Pathway-Level Information ExtractoR (PLIER) to summarize genes into latent variables (LVs), i.e., gene circuits, and link them to biological pathways. LV differences in SX versus CTRL muscle and across sources of muscle tissue (vastus medialis, vastus lateralis, or tensor fascia latae) were determined with ANOVA. Linear models tested for associations between LVs and muscle phenotype on the SX side (inflammation, function, and integrity). DE analysis revealed 360 DE genes (|Log2 fold-difference| ≥ 1, FDR ≤ 0.05) between the SX and CTRL limbs, many associated with inflammation and lipid metabolism. PLIER analyses revealed circuits associated with protein degradation and fibro-adipogenic cell gene expression. Muscle inflammation and function were linked to an LV associated with endothelial cell gene expression highlighting a potential regulatory role of endothelial cells within skeletal muscle. These findings may provide insight into potential therapeutic targets to improve OA rehabilitation before and/or following total joint replacement.


Assuntos
Artroplastia de Quadril , Artroplastia do Joelho , Osteoartrite , Feminino , Humanos , Células Endoteliais , Articulação do Joelho , Osteoartrite/genética , Músculo Esquelético
2.
J Nutr ; 151(5): 1190-1196, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33693735

RESUMO

BACKGROUND: The Dietary Guidelines for Americans (DGAs) published an "ounce equivalents" recommendation to help consumers meet protein requirements with a variety of protein food sources. However, the metabolic equivalency of these varied protein food sources has not been established. OBJECTIVE: We have investigated the hypothesis that the anabolic responses to consumption of ounce equivalents of protein food sources would be directly related to the essential amino acid (EAA) content of the protein food source. METHODS: Following 3 d of dietary control, a total of 56 healthy young adults underwent an 8.5-h metabolic study using stable isotope tracer methodology. The changes from baseline following consumption of 1 of 7 different protein food sources were compared with the baseline value for that individual (n = 8 per group). RESULTS: Consumption of ounce equivalents of animal-based protein food sources (beef sirloin, pork loin, eggs) resulted in a greater gain in whole-body net protein balance above baseline than the ounce equivalents of plant-based protein food sources (tofu, kidney beans, peanut butter, mixed nuts; P < 0.01). The improvement in whole-body net protein balance was due to an increase in protein synthesis (P < 0.05) with all the animal protein sources, whereas the egg and pork groups also suppressed protein breakdown compared with the plant protein sources (P < 0.01). The magnitude of the whole-body net balance (anabolic) response was correlated with the EAA content of the protein food source (P < 0.001). CONCLUSION: The "ounce equivalents" of protein food sources as expressed in the DGAs are not metabolically equivalent in young healthy individuals. The magnitude of anabolic response to dietary proteins should be considered as the DGAs develop approaches to establish healthy eating patterns.


Assuntos
Dieta/normas , Proteínas Alimentares/administração & dosagem , Proteínas Alimentares/classificação , Análise de Alimentos , Adulto , Animais , Composição Corporal , Proteínas do Ovo , Humanos , Insulina/sangue , Insulina/metabolismo , Carne , Proteínas de Plantas , Adulto Jovem
3.
Eur J Nutr ; 60(2): 1141-1148, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32970234

RESUMO

PURPOSE: The purpose of the study was to determine if an actinidin protease aids gastric digestion and the protein anabolic response to dietary protein. METHODS: Hayward green kiwifruit (containing an actinidin protease) and Hort 16A gold kiwifruit (devoid of actinidin protease) were given in conjunction with a beef meal to healthy older subjects. Twelve healthy older males (N = 6) and females (N = 6) were studied with a randomized, double-blinded, crossover design to assess muscle and whole-body protein metabolism before and after ingestion of kiwifruit and 100 g of ground beef. Subjects consumed 2 of each variety of kiwifruit daily for 14 d prior to each metabolic study, and again during each study with beef intake. RESULTS: Hayward green kiwifruit consumption with beef resulted in a more rapid increase in peripheral plasma essential amino acid concentrations. There were significant time by kiwifruit intake interactions for plasma concentrations of EAAs, branched chain amino acids (BCAAs), and leucine (P < 0.01). However, there was no difference in the total amount of EAAs absorbed. As a result, there were no differences between kiwifruit in any of the measured parameters of protein kinetics. CONCLUSION: Consumption of Hayward green kiwifruit, with a beef meal facilitates protein digestion and absorption of the constituent amino acids as compared to Hort 16A gold kiwifruit. CLINICAL TRIAL: NCT04356573, April 21, 2020 "retrospectively registered".


Assuntos
Actinidia , Digestão , Estudos Cross-Over , Proteínas Alimentares/metabolismo , Método Duplo-Cego , Feminino , Frutas , Humanos , Masculino , Proteólise , Carne Vermelha
5.
Am J Physiol Endocrinol Metab ; 309(11): E915-24, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26442881

RESUMO

To determine if age-associated vascular dysfunction in older adults with heart failure (HF) is due to insufficient synthesis of nitric oxide (NO), we performed two separate studies: 1) a kinetic study with a stable isotope tracer method to determine in vivo kinetics of NO metabolism, and 2) a vascular function study using a plethysmography method to determine reactive hyperemic forearm blood flow (RH-FBF) in older and young adults in the fasted state and in response to citrulline ingestion. In the fasted state, NO synthesis (per kg body wt) was ∼ 50% lower in older vs. young adults and was related to a decreased rate of appearance of the NO precursor arginine. Citrulline ingestion (3 g) stimulated de novo arginine synthesis in both older [6.88 ± 0.83 to 35.40 ± 4.90 µmol · kg body wt(-1) · h(-1)] and to a greater extent in young adults (12.02 ± 1.01 to 66.26 ± 4.79 µmol · kg body wt(-1) · h(-1)). NO synthesis rate increased correspondingly in older (0.17 ± 0.01 to 2.12 ± 0.36 µmol · kg body wt(-1) · h(-1)) and to a greater extent in young adults (0.36 ± 0.04 to 3.57 ± 0.47 µmol · kg body wt(-1) · h(-1)). Consistent with the kinetic data, RH-FBF in the fasted state was ∼ 40% reduced in older vs. young adults. However, citrulline ingestion (10 g) failed to increase RH-FBF in either older or young adults. In conclusion, citrulline ingestion improved impaired NO synthesis in older HF adults but not RH-FBF, suggesting that factors other than NO synthesis play a role in the impaired RH-FBF in older HF adults, and/or it may require a longer duration of supplementation to be effective in improving RH-FBF.


Assuntos
Fármacos Cardiovasculares/uso terapêutico , Citrulina/uso terapêutico , Suplementos Nutricionais , Fenômenos Fisiológicos da Nutrição do Idoso , Insuficiência Cardíaca/dietoterapia , Óxido Nítrico/agonistas , Regulação para Cima , Adulto , Idoso , Arginina/sangue , Arginina/metabolismo , Fármacos Cardiovasculares/efeitos adversos , Citrulina/efeitos adversos , Suplementos Nutricionais/efeitos adversos , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiopatologia , Feminino , Antebraço , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Humanos , Hiperemia/etiologia , Cinética , Masculino , Pessoa de Meia-Idade , Óxido Nítrico/sangue , Óxido Nítrico/metabolismo , Fluxo Sanguíneo Regional , Índice de Gravidade de Doença , Adulto Jovem
6.
Physiol Rep ; 9(18): e15055, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34558214

RESUMO

Surgery and anesthesia induce a catabolic response that leads to skeletal muscle protein loss. Previous investigations have observed positive effects of perioperative nutrition. Furthermore, the benefits of exogenous amino acids on muscle protein kinetics are well established. However, no investigation has focused on muscle protein kinetics with and without perioperative amino acid infusion. Thus, we aimed to assess the effect of perioperative amino acid (AA) infusion on muscle protein balance in individuals undergoing elective total hip arthroplasty (THA). Elective THA patients were randomized to undergo a metabolic study prior to surgery (n = 5; control [CON]), intraoperative AA infusion (n = 9), or no AA (n = 13; standard of care [SC]). The CON group was studied prior to surgery to provide nonoperative/non-anesthesia muscle protein kinetic reference values. The bolus infusion method with 13 C6 -phenylalanine injected at time 0, and [15 N]-phenylalanine 30 min later was used to calculate muscle protein synthesis (MPS), protein breakdown (MPB), and net balance (MPS-MPB). Perioperative AA significantly improved muscle net balance as compared to SC (-0.005 ± 0.018%/h vs. -0.052 ± 0.011%/h) but not CON (0.003 ± 0.013%/h). The AA infusion significantly increased muscle net balance via a significant increase in MPS (AA = 0.062 ± 0.007%/h; SC = 0.037 ± 0.004%/h; CON = 0.072% ± 0.005%/h), and a nonsignificant attenuation of MPB (AA = 0.067 ± 0.012%/h; SC = 0.089 ± 0.014%/h; CON = 0.075 ± 0.011%/h). Our data support the use of perioperative AA infusion during elective THA as pragmatic strategy to offset the loss of surgically induced skeletal muscle protein.


Assuntos
Aminoácidos/uso terapêutico , Artroplastia de Quadril/métodos , Músculo Esquelético/metabolismo , Aminoácidos/administração & dosagem , Artroplastia de Quadril/efeitos adversos , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Complicações Pós-Operatórias/epidemiologia
7.
J Gerontol A Biol Sci Med Sci ; 76(7): 1184-1191, 2021 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-33475727

RESUMO

We have investigated the hypothesis that nutritional supplementation of the diet in low-physical-functioning older individuals with a specially formulated composition based on essential amino acids (EAAs) would improve physical function as compared to supplementation with the same amount of whey protein. A third group of comparable volunteers were given nutrition education but no supplementation of the diet. After 6 weeks of whey protein supplementation (n = 32), there was no effect on the distance walked in 6 minutes, but the distance walked improved significantly from the pre-value after 12 weeks of whey supplementation. EAA consumption (n = 28) significantly improved walking distance at both 6 and 12 weeks. The distance walked at 12 weeks (419.0 ± 25.0 m) was 35.4 m greater than the pre-value of 384.0 ± 23.0 m (p < .001). The increase in distance walked by the EAA group was also significantly greater than that in the whey group at both 6 and 12 weeks (p < .01). In contrast, a decrease in distance walked was observed in the control group (n = 32) (not statistically significant, NS). EAA supplementation also improved grip strength and leg strength, and decreased body weight and fat mass. Plasma low-density lipoprotein concentration was significantly reduced in the EAA group, as well as the concentration of macrophage migration inhibitory factor. There were no adverse responses in any groups, and compliance was greater than 95% in all individuals consuming supplements. We conclude that dietary supplementation with an EAA-based composition may be a beneficial therapy in older individuals with low physical functional capacity. Clinical Trials Registration Number: This study was registered with ClinicalTrials.gov: NCT03424265-"Nutritional interventions in heart failure."


Assuntos
Aminoácidos Essenciais/administração & dosagem , Doenças Cardiovasculares/fisiopatologia , Desempenho Físico Funcional , Proteínas do Soro do Leite/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Suplementos Nutricionais , Método Duplo-Cego , Feminino , Avaliação Geriátrica , Humanos , Masculino
8.
Int J Circumpolar Health ; 80(1): 1897222, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33704030

RESUMO

Wild game consumption has been associated with health benefits but the acute influence on human protein metabolism remains unknown. We compared feeding-induced responses of equivalent amounts of free-range reindeer (FR) and commercial beef (CB) on protein kinetics using stable isotope methodology. Seven participants (age: 40 ± 14 years; body mass index: 24 ± 3 kg/m2) completed two randomised studies, ingesting 2 oz of FR or CB. L-[ring 2H5]phenylalanine & L-[ring 2H2]tyrosine were delivered via primed, continuous intravenous infusion. Blood samples were collected during the basal period and following consumption of FR or CB. Feeding-induced changes in whole-body protein synthesis (PS), protein breakdown (PB), and net protein balance (NB) were determined via plasma sample isotope enrichment analysis by gas chromatography-mass spectrometry; plasma essential amino acid (EAA) concentrations were determined by liquid chromatography-electrospray ionisation-mass spectrometry. Plasma post-prandial EAA concentrations were higher with FR compared to CB (P < 0.05). The acute feeding-induced PS response was not different, but PB was reduced and contributed to a superior level of NB (P < 0.00001) in FR compared to CB. Our results demonstrate that FR may influence more favourable protein metabolism than CB. These data support potential health benefits of wild game onf whole-body protein.Abbreviations: BMI: body mass index; DIAAS: digestible indispensable amino acid score; CB: commercial beef; EAA: essential amino acids; FR: free-range reindeer; Ra: rate of appearance; UAF: University of Alaska Fairbanks; USDA: USA Department of Agriculture.


Assuntos
Rena , Aminoácidos Essenciais/metabolismo , Animais , Índice de Massa Corporal , Bovinos , Humanos , Período Pós-Prandial , Biossíntese de Proteínas , Rena/metabolismo , Estados Unidos
9.
J Int Soc Sports Nutr ; 17(1): 9, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32041644

RESUMO

BACKGROUND: We have determined the acute response of protein kinetics to one or two servings (6.3 g and 12.6 g) of a proprietary composition containing free-form essential amino acids (EAA) (3.2 g EAA per serving) and whey protein (2.4 g per serving), as well as the response to consumption of a popular whey-based protein supplement (Gatorade Recover) (17 g; 12.6 g protein). METHODS: Whole-body rates of protein synthesis, breakdown and net balance (taken to be the anabolic response) were determined using primed-constant infusions of 2H5-phenylalnine and 2H2-tyrosine. Muscle protein fractional synthetic rate (FSR) was also determined with the 2H5-phenylalanine tracer. RESULTS: Plasma EAA levels increased following consumption of all beverages, with the greatest response in the high-dose EAA/protein composition. Similarly, the increase in net balance between whole-body protein synthesis and breakdown was greatest following consumption of the high-dose EAA/protein composition, while the low-dose EAA/protein composition and Gatorade Recover induced similar increases in net balance. When the net balance response was normalized for the total amount of product given, the high- and low-dose EAA/protein beverages were approximately 6- and 3-fold more anabolic than the Gatorade Recover, respectively. The greater anabolic response to the EAA/protein composition was due to greater increases in whole-body protein synthesis with both doses, and a markedly greater suppression of whole-body protein breakdown in the high-dose group. Muscle protein FSR after beverage consumption reflected changes in whole-body protein synthesis, with the larger EAA/protein dose significantly increasing FSR. CONCLUSION: We conclude that a composition of a balanced EAA formulation combined with whey protein is highly anabolic as compared to a whey protein-based recovery product, and that the response is dose-dependent. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03502941. This trial was registered on April 19, 2018.


Assuntos
Aminoácidos Essenciais/farmacologia , Suplementos Nutricionais , Proteínas Musculares/metabolismo , Biossíntese de Proteínas , Proteínas do Soro do Leite/farmacologia , Adulto , Aminoácidos Essenciais/sangue , Estudos Cross-Over , Voluntários Saudáveis , Humanos , Masculino , Adulto Jovem
10.
Clin Nutr ; 38(6): 2821-2826, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30638738

RESUMO

BACKGROUND & AIMS: Older individuals are susceptible to the loss of muscle and accumulation of fat. To address this problem, we have compared protein kinetics following consumption of an essential amino acid (EAA)-enriched meal replacement (EMR) to consumption of a high-protein meal replacement beverage (Bariatric Advantage, BA) using stable isotope methodology. METHODS: Eight older (67 ± 2), obese (35 ± 2 kg/m2) female and male participants completed two studies using a randomized, crossover design in which they ingested each meal replacement. The isotopic tracers L-[2H5]phenylalanine & L-[2H2]tyrosine were delivered via primed, continuous intravenous infusion throughout a basal period and following consumption of EMR or BA. We determined changes in whole body protein synthesis (PS), protein breakdown (PB), and net protein balance (NB) from fasted states via analysis of plasma samples by LC-ESI-MS. RESULTS: PS was higher (P = 0.03) and PB was less (P = 0.005) with EMR in comparison to BA. As a result, NB was much greater (P = 0.00003) following the ingestion of EMR as compared to BA. CONCLUSIONS: In comparison with BA, which has a higher amount of intact protein that any other meal replacement, EMR promoted a greater increment in NB. These data support the potential efficacy of EMR as a meal replacement for the preservation of lean tissue mass during weight loss in older, overweight individuals.


Assuntos
Aminoácidos Essenciais/administração & dosagem , Aminoácidos Essenciais/metabolismo , Alimentos Fortificados , Avaliação Geriátrica/métodos , Sobrepeso/metabolismo , Proteínas/metabolismo , Idoso , Idoso de 80 Anos ou mais , Alaska , Estudos Cross-Over , Método Duplo-Cego , Feminino , Avaliação Geriátrica/estatística & dados numéricos , Humanos , Masculino , Refeições , Pessoa de Meia-Idade
11.
Clin Nutr ; 37(6 Pt A): 2076-2083, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29066101

RESUMO

BACKGROUND & AIMS: It has been demonstrated that the relative content and profile of essential amino acids (EAA) play a determining role for stimulation of muscle protein synthesis (MPS) following intake of pure EAA or protein alone. METHODS: To test if this also holds in the context of mixed meals at both whole body and muscle levels, twelve older subjects (57-74 yrs) received primed continuous infusion of L-[ring-2H5]phenylalanine and L-[ring-2H2]tyrosine over a 9-h experimental period to determine whole body protein kinetics and MPS in the fasted state and following consumption of egg-based (EGG) or cereal-based (CEREAL) isocaloric and isonitrogenous breakfast. A standardized lunch, primarily consisting of beef protein was also consumed by each group. Whole body protein kinetics [protein synthesis (PS), breakdown (PB), and net balance (NB)] were expressed as changes from basal fasted period. RESULTS: We found that EGG breakfast resulted in a greater NB through a greater suppression of PB compared with the CEREAL breakfast. The greater NB during the post-breakfast period with the EGG was normalized following the standard lunch despite the sustained elevations in plasma EAA concentrations. However, the EGG breakfast stimulated both PS and PB compared with the CEREAL breakfast during the post-lunch period. MPS was not different between meals despite larges differences in the plasma EAA responses. CONCLUSIONS: We conclude that in the context of mixed meals, quality of protein affects NB through changes in protein breakdown and affects protein turnover following subsequent meal intake.


Assuntos
Aminoácidos Essenciais , Desjejum/fisiologia , Proteínas Alimentares/metabolismo , Idoso , Aminoácidos Essenciais/sangue , Aminoácidos Essenciais/química , Aminoácidos Essenciais/metabolismo , Aminoácidos Essenciais/farmacocinética , Glicemia/metabolismo , Proteínas do Ovo/metabolismo , Feminino , Humanos , Insulina/sangue , Marcação por Isótopo , Masculino , Pessoa de Meia-Idade , Proteínas de Vegetais Comestíveis/metabolismo , Tirosina/química , Tirosina/metabolismo , Tirosina/farmacocinética
12.
Am J Clin Nutr ; 86(2): 451-6, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17684218

RESUMO

BACKGROUND: Sarcopenia is a debilitating condition afflicting the elderly that may be facilitated by insufficient or ineffectual intake of dietary protein. We previously showed that free-form essential amino acids acutely stimulate muscle protein synthesis in both the young and the elderly. However, the ability of an actual protein-rich food to stimulate anabolism in the young and the elderly has not been explored. OBJECTIVE: We aimed to characterize changes in plasma amino acid concentrations and to quantify muscle protein synthesis in healthy young (41 +/- 8 y old; n = 10) and elderly (70 +/- 5 y old; n = 10) persons after ingestion of a 113-g (4-oz) serving of lean beef. DESIGN: Venous blood samples and vastus lateralis muscle biopsy samples were obtained during a primed (2.0 mumol/kg) constant infusion (0.08 mumol.kg(-1).min(-1)) of l-[ring-(13)C(6)] phenylalanine. Plasma amino acid concentrations were measured and a mixed-muscle fractional synthesis rate (FSR) was calculated during the premeal period and for 5 h after beef ingestion. RESULTS: Mixed-muscle FSR increased by approximately 51% in both the elderly (mean +/- SE measurements: 0.072 +/- 0.004%/h and 0.108 +/- 0.006%/h before and after the meal, respectively) and the young (0.074 +/- 0.005%/h and 0.113 +/- 0.005%/h before and after the meal, respectively) after beef ingestion (P < 0.001). Plasma amino acid concentrations peaked at approximately 100 min after beef ingestion in both age groups but were substantially higher in the elderly (2185 +/- 134 nmol/mL compared with 1403 +/- 96 nmol/mL; P < 0.001). CONCLUSION: Despite differences in the concentration of amino acids in the plasma precursor pool, aging does not impair the ability to acutely synthesize muscle protein after ingestion of a common protein-rich food.


Assuntos
Envelhecimento/fisiologia , Aminoácidos/sangue , Proteínas Alimentares/metabolismo , Tecido Adiposo/anatomia & histologia , Adulto , Idoso , Aminoácidos Essenciais/análise , Índice de Massa Corporal , Isótopos de Carbono , Feminino , Humanos , Infusões Intravenosas , Masculino , Carne/análise , Pessoa de Meia-Idade , Fenilalanina/administração & dosagem , Fenilalanina/farmacocinética
13.
Physiol Rep ; 5(15)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28778993

RESUMO

Growth hormone treatment has gained attention over the past decade as a treatment for heart failure. Human growth hormone (HGH) must be administered by injections (usually daily), so there is considerable advantage to stimulation of endogenous secretion by amino acid-based nutritional supplementation. However, studies investigating the effect of amino acid (AA) supplementation show conflicting results. Therefore, in this study we aimed to investigate the effect of nutritional supplementation on HGH production in elderly women with heart failure. Eight elderly women with heart failure participated in this randomized cross-over study. Plasma HGH concentration was measured before and for 4 h following ingestion of a mixture of protein, carbohydrate, and fat or an AA beverage. HGH concentration was determined with ELISA kits and AA concentrations were analyzed by Liquid Chromatography-Mass Spectrometry (LCMS). Linear mixed models was performed to analyze the effect of time, treatment, and interaction. Plasma arginine and lysine concentrations were significantly higher after consumption of the AA drink compared to the mixture of protein, carbohydrate, and fat. Nonetheless, only ingestion of the protein, carbohydrate, and fat mixture (meal replacement) increased HGH concentration. HGH concentration was increased in elderly women with heart failure following consumption of a meal replacement containing protein, carbohydrate, and fat. Consumption of a mixture of amino acids failed to increase HGH concentration despite significantly greater elevations in plasma amino acid concentrations, including arginine and lysine. The stimulatory effect of the protein/carbohydrate/fat mixture was presumably mediated by factors other than increases in free amino acid concentrations.


Assuntos
Anabolizantes/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Hormônio do Crescimento Humano/sangue , Idoso , Idoso de 80 Anos ou mais , Anabolizantes/administração & dosagem , Arginina/sangue , Suplementos Nutricionais , Feminino , Insuficiência Cardíaca/sangue , Hormônio do Crescimento Humano/metabolismo , Humanos , Lisina/sangue
14.
BMC Nutr ; 32017.
Artigo em Inglês | MEDLINE | ID: mdl-28713581

RESUMO

BACKGROUND: There is a great deal of controversy as to whether higher protein intake improves or worsens insulin sensitivity in humans. The purpose of the study was to determine the influence of a short-term elevation in dietary protein on hepatic and peripheral insulin sensitivity in twelve older subjects (51-70 yrs) with metabolic syndrome. METHODS: Individuals were randomly assigned to one of the dietary groups: recommended protein intake (RPI, 10% of daily calorie intake) or elevated protein intake (EPI, 20% of daily calorie intake) for 4 weeks. Prior to and immediately following the dietary intervention, subjects were studied with primed continuous infusion of [6,6-2H2]glucose and [1-3C]glucose dissolved in drink during the dual tracer oral glucose tolerance test (DT OGTT) to determine hepatic and peripheral insulin sensitivity. Plasma lipids were measured pre- and post-dietary intervention. RESULTS: In both intervention groups: 1) hepatic insulin sensitivity as assessed by the endogenous glucose rate of appearance (glucose Ra), 2) peripheral insulin sensitivity as assessed by the metabolic clearance rate of glucose normalized to plasma glucose concentration (MCR) and/or the rate of glucose utilization (Rd) or 3) glucose/insulin AUC were unaffected by the diets. Moreover, fasting lipid was not affected by RPI or EPI. CONCLUSION: Our findings suggest that a short-term elevation in EPI with correspondingly higher branched chain amino acid (BCAA) contents has no detrimental impact on hepatic and peripheral insulin sensitivity or plasma lipid parameters in older adults with metabolic syndrome. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02885935; This trial was registered retrospectively (Study start date, April 01, 2013, date of registration, August 26, 2016).

15.
Nutr Metab (Lond) ; 11(1): 49, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25324894

RESUMO

CONTEXT: Lysine supplementation may have a positive influence on the regulation of glucose metabolism but it has not been tested in the geriatric population. OBJECTIVE: We evaluated the impact of acute lysine supplementation using three randomized experimental scenarios: 1) oral glucose alone (control), 2) oral glucose and low-dose lysine (2 grams), and oral glucose and high dose lysine (5 grams) lysine in 7 older (66 ± 1 years/age), overweight/obese (BMI = 28 ± 2 kg/m(2)) individuals. METHODS: We utilized a dual tracer technique (i.e., [6,6-(2)H2] glucose primed constant infusion and 1-[(13)C] glucose oral ingestion) during an oral glucose tolerance test (OGTT) to examine differences in hepatic and peripheral insulin sensitivity under all three scenarios. RESULTS: Post-absorptive plasma glucose and insulin concentrations were not different between the three trials. Similarly, the response of glucose and insulin concentrations during the oral glucose tolerance tests (OGTT) was similar in the three trials. The results of the Matsuda index (ISI/M) were also not different between the three trials. As an index of hepatic insulin sensitivity, there were no significant differences in the endogenous glucose rate of appearance (glucose Ra) for control, 2 g lysine and 5 g lysine (1.2 ± 0.1, 1.1 ± 0.1, 1.3 ± 0.1 mg•kg(-1)•min(-1)), respectively. With respect to peripheral insulin sensitivity, there were no significant differences in the glucose rate of disappearance (glucose Rd) for control, 2 g lysine and 5 g lysine (4.2 ± 0.1, 4.3 ± 0.2, and 4.5 ± 0.4 mg•kg(-1)•min(-1)), respectively. CONCLUSIONS: Previous studies in younger participants have suggested that lysine may have a beneficial effect on glucose metabolism. However, acute lysine supplementation in the older population does not facilitate beneficial changes in glucose Ra or glucose Rd.

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