Suplementação com HMB atenua perda de força e massa muscular associada ao envelhecimento

Publicado em 21/04/2012 por Lucas Guimarães Ferreira
J Int Soc Sports Nutr. 2012 Apr 18;9(1):18. [Epub ahead of print]

Beta-hydroxy-beta-methyl-butyrate blunts negative age-related changes in body composition, functionality and myofiber dimensions in rats.

Abstract

ABSTRACT: Purpose To determine the effects of 16 wk. of beta-hydroxy-beta-methylbutyrate (HMB) administration on age-related changes in functionality and diffusion tensor imaging (DTI) determined myofiber dimensions.

METHODS: Twelve young (44 wk.), 6 middle-aged (60 wk.), 10 old (86 wk.), and 5 very old (102 wk.) male Fisher-344 rat’s body composition and grip strength were assessed at baseline. Following, 6 young, 6 middle-aged, 5 old and 5 very old rats were sacrificed for baseline myofiber dimensions and gene transcript factor expression in the soleus (SOL) and gastrocnemius (GAS). The remaining 6 young and 5 old rats were given HMB for 16 wk. and then sacrificed.

RESULTS: Fat mass increased in the middle-aged control condition (+49%) but not the middle-aged HMB condition. In addition, fat mass declined (56%) in the old HMB condition but not the old control condition. Normalized strength declined and maintained respectively in the control and HMB conditions from 44 to 60 wk. and increased (+23%) (p < 0.05) from 86 to 102 wk. in only the HMB condition. Declines occurred in myofiber size in all muscles from 44 to 102 wk. in the control condition(10 to 15%), but not HMB condition. Atrogin-1 mRNA expression in the SOL and GAS muscles was greater in the 102-wk control condition than all other conditions: SOL (+45%) and GAS (+100%). This elevation was blunted by HMB in the 102 wk. old SOL. There was a condition effect in the SOL for myogenin, which significantly increased (+40%) only in the 102-wk. HMB group relative to the 44-wk. group.

CONCLUSIONS: HMB may blunt age-related losses of strength and myofiber dimensions, possibly through attenuating the rise in protein breakdown.

 

http://www.ncbi.nlm.nih.gov/pubmed/22512917

Publicado em Músculo, nutrição, paper, suplementação | Deixe um comentário

Development, Function and Repair of the Muscle Cell Meeting

Publicado em 09/03/2012 por Lucas Guimarães Ferreira

June 4-8, 2012

Kimmel Center, New York University
New York, NY, USA

A Frontiers in Myogenesis meeting organized the Society for Muscle Biology

Organizers: Mary Baylies, Sloan-Kettering Institute, New York, USA. Vittorio Sartorelli, NIAMS/NIH, Bethesda, USA. David Sassoon, INSERM/University of Paris, France.

Mais informações: aqui

Publicado em evento | Deixe um comentário

Proteínas e recuperação muscular

Publicado em 28/02/2012 por Lucas Guimarães Ferreira

Dietary Protein and Muscle Recovery

Richard Kreider (Texas A & M University)

ABSTRACT: High-intensity and prolonged exercise creates the potential for a catabolic state resulting in protein degradation. The repair of muscle tissue following intense exercise is critical in promoting recovery and optimizing training adaptations. Individuals engaged in intense exercise training have greater protein needs. Additionally, research shows that timing dietary protein and/ or amino acid ingestion can play an important role in promoting protein synthesis and recovery from exercise. The purpose of this perspectives article is to overview the role of dietary protein in optimizing recovery from exercise, and how ingestion of protein and/or amino acids prior to and following exercise can optimize protein synthesis and recovery.

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Publicado em paper, suplementação | Deixe um comentário

Suplementação com leucina promove aumento de síntese protéica em idosos

Publicado em 28/02/2012 por Lucas Guimarães Ferreira
Clin Nutr. 2012 Feb 20. [Epub ahead of print]

Leucine supplementation chronically improves muscle protein synthesis in older adults consuming the RDA for protein.

Casperson SL, Sheffield-Moore M, Hewlings SJ, Paddon-Jones D.

Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA.
Abstract

BACKGROUND & AIM: Protein-energy supplementation is routinely employed to combat muscle loss. However, success is often compromised by increased satiety, poor palatability, high costs and low compliance.

METHODS: For 2-weeks we supplemented meals of older individuals with leucine (4 g/meal; 3 meals/day; days 2-14). Metabolic studies were performed prior to (Day 1) and following (Day 15) supplementation. Leucine was not provided on metabolic study days. Venous blood and vastus lateralis muscle biopsies were obtained during a primed constant infusion of L-[ring-(13)C(6)] phenylalanine. Mixed muscle fractional synthesis rate (FSR), body composition and markers of nutrient signaling (mTOR, 4E-BP1 and p70S6K1 phosphorylation) were measured before and after a low protein/carbohydrate simulated meal.

RESULTS: The meal modestly increased FSR on Day 1 (postabsorptive: 0.063 ± 0.004 vs. postprandial: 0.075 ± 0.006%/h; p = 0.03), however, two weeks of leucine supplementation increased postabsorptive FSR (p = 0.004) and the response to the meal (p = 0.01) (postabsorptive: 0.074 ± 0.007 vs. postprandial: 0.10 ± 0.007%/h). Changes in FSR were mirrored by increased phosphorylation of mTOR, 4E-BP1 and p70S6K1 (p ≤ 0.1). No change in fat free mass was observed (p > 0.05).

CONCLUSIONS: In older adults, leucine supplementation may improve muscle protein synthesis in response to lower protein meals.

Copyright © 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

PMID: 22357161 [PubMed – as supplied by publisher]
Publicado em Músculo, paper, suplementação | Deixe um comentário

“But if you want the real lowdown, we’ll need some of your DNA”

Publicado em 25/02/2012 por Lucas Guimarães Ferreira

Publicado em cartoon | Deixe um comentário

O que você deve fazer para ser co-autor de um trabalho científico?

Publicado em 24/02/2012 por Lucas Guimarães Ferreira

Para ser considerado um co-autor de um manuscrito publicado em período científico proveniente de um trabalho sob a minha orientação, você deve contribuir com ao menos 2 das 5 categorias listadas a seguir.

  1. Contribuir com a concepção e delineamento do estudo que serviu de base para o manuscrito;
  2. Prover supervisão, recursos e/ou materiais indispensáveis para a finalização do estudo;
  3. Desenvolver um método, dispositivo, sistema ou processo essencial para a finalização do estudo;
  4. Participar da coleta, processamento, análise e/ou interpretação dos dados;
  5. Contribuir com a revisão da literatura, escrita e revisão crítica do manuscrito.
Se você contribuiu para algum trabalho de acordo com as diretrizes listadas acima e não foi reconhecido como autor, entre em contato comigo imediatamente. Em casos nos quais um acordo entre as duas partes não ocorrer, uma terceira parte – imparcial – será consultada. Esta pessoa será selecionada em comum acordo com todas as partes envolvidas.

É importante frisar que cada pesquisador possui seus próprios critérios para determinação de co-autoria. Por considerá-las de bom senso e de acordo com a ética acadêmica, utilizo as mesmas diretrizes disponibilizadas no site do Prof. Keith Baar da Universidade da California (http://fmblab.com/Authorship.html).

Ética e ciência não devem andar separadas jamais.

Publicado em ciência, ética | 1 Comentário

Vídeo: O Dogma Central da Genética (legendado em inglês)

Publicado em 17/02/2012 por Lucas Guimarães Ferreira

Animation: The Central Dogma

Publicado em bioquímica, genética, vídeo | Deixe um comentário

Encontro da American Physiological Society sobre Biologia Integrativa do Exercício

Publicado em 08/02/2012 por Lucas Guimarães Ferreira

Informações: http://www.the-aps.org/mm/Conferences/APS-Conferences/2012-Conferences/Integrative-Biology-of-Exercise

Publicado em evento | Deixe um comentário

Regulação Molecular da Miogênese

Publicado em 06/02/2012 por Lucas Guimarães Ferreira
Cold Spring Harb Perspect Biol. 2012 Feb 1;4(2). pii: a008342. doi: 10.1101/cshperspect.a008342.

Building muscle: molecular regulation of myogenesis.

Bentzinger CF, Wang YX, Rudnicki MA.

The Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Health Research Institute, Ottawa, Ontario K1H 8L6, Canada.

Abstract

The genesis of skeletal muscle during embryonic development and postnatal life serves as a paradigm for stem and progenitor cell maintenance, lineage specification, and terminal differentiation. An elaborate interplay of extrinsic and intrinsic regulatory mechanisms controls myogenesis at all stages of development. Many aspects of adult myogenesis resemble or reiterate embryonic morphogenetic episodes, and related signaling mechanisms control the genetic networks that determine cell fate during these processes. An integrative view of all aspects of myogenesis is imperative for a comprehensive understanding of muscle formation. This article provides a holistic overview of the different stages and modes of myogenesis with an emphasis on the underlying signals, molecular switches, and genetic networks.

PMID: 22300977 [PubMed – in process]
Download do artigo completo: [4Shared]
Publicado em Músculo, paper, plasticidade muscular, sinalização celular | Deixe um comentário

Suplementação com Whey Protein promove maior estímulo da síntese protéica miofibrilar quando comparada à suplementação com caseína micelar em repouso e após exercício de força em idosos

Publicado em 01/02/2012 por Lucas Guimarães Ferreira
Br J Nutr. 2012 Jan 31:1-5. [Epub ahead of print]


Greater stimulation of myofibrillar protein synthesis with ingestion of whey protein isolate v. micellar casein at rest and after resistance exercise in elderly men.

Burd NA, Yang Y, Moore DR, Tang JE, Tarnopolsky MA, Phillips SM.

Source

Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1.

Abstract

We aimed to determine the effect of consuming pure isolated micellar casein or pure whey protein isolate on rates of myofibrillar protein synthesis (MPS) at rest and after resistance exercise in elderly men. Healthy elderly men (72 (sem 1) years; BMI 26·4 (sem 0·7) kg/m2) were divided into two groups (n 7 each) who received a primed, constant infusion of l-[ring-13C6]phenylalanine to measure MPS at rest and during 4 h of exercise recovery. Participants performed unilateral leg resistance exercise followed by the consumption of isonitrogenous quantities (20 g) of casein or whey. Blood essential amino acids and leucine concentration peaked 60 min post-drink and were greater in amplitude after whey protein ingestion (both, P < 0·05). MPS in the rested leg was 65 % higher (P = 0·002) after ingestion of whey (0·040 (sem 0·003) %/h) when compared with micellar casein (0·024 (sem 0·002) %/h). Similarly, resistance exercise-stimulated rates of MPS were greater (P < 0·001) after whey ingestion (0·059 (sem 0·005) %/h) v. micellar casein (0·035 (sem 0·002) %/h). We conclude that ingestion of isolated whey protein supports greater rates of MPS than micellar casein both at rest and after resistance exercise in healthy elderly men. This result is probably related to a greater hyperaminoacidaemia or leucinaemia with whey ingestion.
Publicado em nutrição, paper, suplementação, whey protein | 3 Comentários