Dataset Information

Inadequate protein intake affects skeletal muscle transcript profiles in older humans.

ABSTRACT:

Background

Inadequate dietary protein intake causes adverse changes in the morphology and function of skeletal muscle. These changes may be reflected in early alterations in muscle messenger RNA levels.

Objective

This study assessed whether inadequate protein intake differentially affects skeletal muscle transcript concentrations and expression profiles in older adults.

Design

Twenty-one older men and women (aged 55-80 y) consumed controlled diets that provided 1.2 g protein x kg(-1) x d(-1) (adequate protein) for 1 wk and then were randomly assigned to consume either 0.5 g protein x kg(-1) x d(-1) [inadequate protein (IP) group; n=11] or 1.2 g protein x kg(-1) x d(-1) (control group; n=10) for a second week. RNA was isolated from fasting-state vastus lateralis biopsy samples obtained at the end of each period, and transcript levels in the IP group were measured by using microarray analysis. Changes in selected transcript levels were confirmed by real-time polymerase chain reaction in both groups.

Results

Analysis of variance showed 529 differentially expressed transcripts (P<0.05) after inadequate protein intake. Using the false discovery rate (FDR) correction to adjust for multiple comparisons, we observed that 85 transcripts were differentially expressed: 54 were up-regulated and 31 were down-regulated. The differentially expressed transcripts were in functional classes for immune, inflammatory, and stress responses (predominantly up-regulated); contraction, movement, and development (up-regulated); extracellular connective tissue (up-regulated); energy metabolism (down-regulated); protein synthesis (down-regulated); and proliferation (down-regulated). Diet-related differences in the expression of 9 transcripts were cross-validated by using real-time polymerase chain reaction.

Conclusion

The results document changes in skeletal muscle transcript levels induced by short-term inadequate protein intakes in older humans that might precede adverse metabolic, functional, and structural events, including muscle wasting.

SUBMITTER: Thalacker-Mercer AE

PROVIDER: S-EPMC2447912 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature

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Publications

Inadequate protein intake affects skeletal muscle transcript profiles in older humans.

Thalacker-Mercer Anna E AE Fleet James C JC Craig Bruce A BA Carnell Nadine S NS Campbell Wayne W WW

The American journal of clinical nutrition 20070501 5

<h4>Background</h4>Inadequate dietary protein intake causes adverse changes in the morphology and function of skeletal muscle. These changes may be reflected in early alterations in muscle messenger RNA levels.<h4>Objective</h4>This study assessed whether inadequate protein intake differentially affects skeletal muscle transcript concentrations and expression profiles in older adults.<h4>Design</h4>Twenty-one older men and women (aged 55-80 y) consumed controlled diets that provided 1.2 g protei ...[more]

PMID: 17490972

Similar Datasets

Project description:Inadequate protein intake initiates an accommodative response with adverse changes in skeletal muscle function and structure. mRNA level changes due to short-term inadequate dietary protein might be an early indicator of accommodation. The aims of this study were to assess the effects of dietary protein and the diet-by-age interaction on the skeletal muscle transcript profile. Self-organizing maps were used to determine expression patterns across protein trials. 958 transcripts were differentially expressed (P<0.05) with diet and 853 had a diet-by-age interaction (P<0.05) using ANOVA. The results for diet alone revealed that P63 was associated with up-regulation of transcripts related to ubiquitin-dependent protein catabolism and muscle contraction and P63 and P94 resulted in up-regulation of transcripts related to apoptosis and down-regulation of transcripts related to cell differentiation; muscle and organ development; extracellular space; and responses to stimuli and stress. The diet-by-age expression patterns demonstrated that across the three protein trials transcripts related to protein metabolism were affected by age. Changes in skeletal muscle mRNA levels in the younger and older males to protein intake near or below the RDA are indicative of an early accommodative response. 5052 transcripts were determined as differentially expressed (P<0.05) between the younger and older males, of which 2556 met the False Discovery Rate correction (P=0.0081). The age-related changes in the transcript profile were consistent with aging skeletal muscle phenotypes including; mitochondrial dysfunction (UP- and DOWN-regulation), RNA splicing (UP), oxidative stress (UP), apoptosis (UP), and energy metabolism (DOWN). Experiment Overall Design: 22 healthy free-living younger (21-43 y, n=12) and older (63-79 y, n=10) males completed three controlled feeding trials with protein intakes of 63% (P63: 0.50 g/kg), 94% (P94: 0.75 g/kg), and 125% (P125: 1.00 g/kg) of the recommended dietary allowance (RDA). A fasting state vastus lateralis biopsy was taken from the dominant leg of each subject on day 12 of each trial following an overnight fast. Total RNA was isolated from the muscle samples using Tri-Reagent and the manufacture's protocol.

Dataset Information

Inadequate protein intake affects skeletal muscle transcript profiles in older humans.

Background

Objective

Design

Results

Conclusion

Publications

Inadequate protein intake affects skeletal muscle transcript profiles in older humans.

Similar Datasets

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