Effects of ageing and human whole body and muscle protein turnover

Dorrens, Jennifer; Rennie, Michael J.

doi:10.1034/j.1600-0838.2003.00306.x

Cited by 51 publications

(40 citation statements)

References 61 publications

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“…Sarcopenia arises from a combination of factors including reduced caloric and protein intake and lower myofibrillar protein turnover due to lessen protein synthesis and increased protein degradation (2). These changes are responsible for quantitative alteration of the major contractile proteins such as myosin and actin (3).…”

mentioning

confidence: 99%

Essential Amino Acids Improve Insulin Activation of Akt/mTOR Signaling in Soleus Muscle of Aged Rats

Flati

Caliaro

Speca

et al. 2010

Int J Immunopathol Pharmacol

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Essential amino acids (EAA) improve basal muscle protein synthesis in the elderly. Nevertheless, in settings of prolonged supplementation, putative signal pathways of EAA are currently unknown. The purpose of this study was to test the effects of prolonged supplementation of EAA enriched mixture (12-L-Amin) on Insulin/Insulin-like Growth Factor-1 (IGF1) pathway by measuring total and phosphorylated Akt (Ser 473 ) and its upstream (IRS1 at Ser 636 ) and downstream (mTOR at Ser 2448 , p70 S6K at Thr 389 ) targets in basal conditions and following acute insulin (0.1 U/L) incubation in vitro. To this aim, soleus muscles were dissected from male Wistar rats divided in three groups of 7 each: adults (AD, 10 mo of age), elderly (EL, 22 mo of age) and elderly supplemented (EL-AA, 12-L-Amin 1.5gr/Kg die in drinking water for 3mo). EL showed reduced basal and post-insulin mTOR and p70 S6K activation and reduced post-insulin IRS1 degradation relative to AD. EL-AA showed an increase of post-insulin Akt activation, no change in basal and post-insulin phospho-mTOR, lower reduction of phospho-p70s 6K and increased post-insulin IRS1 degradation relative to AD. These results demonstrate that chronic 12-LAmin administration exerts anti-ageing effects on the activation/inactivation of the Insulin/IGFlImTOR pathway which is identified as putative target of EAA in the elderly.In ageing the foremost factor shaping skeletal muscle phenotype is quantitative reduction of mass leading to loss of strength (sarcopenia) (1). Sarcopenia arises from a combination of factors including reduced caloric and protein intake and lower myofibrillar protein turnover due to lessen protein synthesis and increased protein degradation (2). These changes are responsible for quantitative alteration of the major contractile proteins such as myosin and actin (3).A likely mechanism which contributes sarcopenia is the alteration of post-transcriptional events. Studies on humans reported that ageing is associated with reduced availability of specific mRNAs encoding myofibrillar proteins and deregulation of Insulin/Insulin-like growth factor 1 (IGFI) activated metabolic pathway known to playa role in translation ofmRNAs encoding for essential components of the

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mentioning

confidence: 99%

Essential Amino Acids Improve Insulin Activation of Akt/mTOR Signaling in Soleus Muscle of Aged Rats

Flati

Caliaro

Speca

et al. 2010

Int J Immunopathol Pharmacol

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“…Hoje a recomendação protéica para atletas de musculação é cerca de 1,8g/kg de peso/dia (7,22) . A associação de aminoácidos essenciais com carboidrato estimula o balanço protéico com aumento da síntese e redução do catabolismo protéico (27,28) , isto porque a ingestão de carboidrato potencializa a resposta ao efeito anabólico do exercício (29) . Miller et al (30) mostraram que o consumo protéico com carboidrato resultou em aumento da síntese protéica muscular nos períodos de uma hora e duas horas após o treino, período este que coincide com o pico da síntese e catabolismo protéico muscular nas condições de repouso (pós-treino) (31,32) .…”

Section: Discussionunclassified

Efeito da oferta dietética de proteína sobre o ganho muscular, balanço nitrogenado e cinética da 15N-glicina de atletas em treinamento de musculação

Maestá

Cyrino

Angeleli

et al. 2008

Rev Bras Med Esporte

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RESUMOO efeito da oferta crescente de proteína sobre o ganho muscular, balanço nitrogenado e cinética da 15 N-glicina de atletas de musculação foi estudado em seis jovens saudáveis, praticantes de treinamento com pesos (> 2 anos), sem uso de anabolizantes e concordes com os princípios éticos da pesquisa. Todos receberam adequações dietéticas (0,88g de proteína/kg/dia) pré-experimento de 2 semanas (D1) após o que se ofereceu, por idêntico período, dieta contendo 1,5g de proteína/kg de peso corporal/dia com 30kcal/g de proteína (dieta D2). A seguir receberam, nas próximas 2 semanas, a dieta D3, contendo 2,5g de proteína/kg de peso corporal/dia e 30 kcal/g proteína. As avaliações antropométricas, alimentares, biquímicas, balanço nitrogenado (BN) e cinética com 15 N-glicina foram realizadas no início do estudo, pós D1 (M0) e no último dia das dietas D2 (M1) e D3 (M2). Ao final do estudo (4 semanas) houve aumento significativo na massa muscular (1,63±0,9kg), sem diferença entre D2 e D3. O BN acompanhou o consumo protéico/energético (M0 = -7,8g/dia; M1 = 5,6g/dia e M2 = 16,6g/dia) e a síntese protéica acompanhou o BN, com significância estatística (p<0,05) em relação ao basal (M0) mas semelhante entre D2 e D3 (M1 = 49,8±12,2g N/dia e M2 = 52,5±14,0g N/dia) e sem alteração significativa do catabolismo. Assim, os dados de BN e cinética da 15 N-glicina indicam que a ingestão protéica recomendável para esses atletas é superior ao preconizado para sedentários (0,88g/kg) e inferior a 2,5g/kg de peso, sendo no caso, 1,5g de proteína/kg de peso/dia com ajuste do consumo energético para 30 kcal/g de proteína.Palavras-chave: exercício, dieta, proteína, síntese, músculo. ABSTRACTThe effect of increased protein intake on the muscle mass gain, nitrogen balance and 15 N-glycine kinetics was studied in six young, healthy subjects practitioners of strength training (> 2 years), without use of anabolic steroids and in agreement with the ethical principles of the research. All athletes received adequate diet (0.88g protein/kg/day) during 2 weeks prior the study (D1), and thereafter with diet providing 1.5g of protein/kg/day and 30kcal/g of protein (D2 diet) for the subsequent 2 weeks. Later on, they all received diet with 2.5g of protein/kg/day (D3 diet) and 30 kcal/g protein for the last two weeks. Body composition, food intake, blood biochemistry, nitrogen balance (NB) and 15 N-glycine kinetics were determined at the beginning, after D1 (M0) and in the last days of the D2 (M1) and D3 (M2). The results showed at the end of the study (4 weeks) significant increase in muscle mass (1.63±0.9kg), without difference between D2 and D3. The NB followed the protein/energy consumption (M0 = -7.8g/day; M1 = 5.6g/day and D3 = 16.6g/day), the protein synthesis followed the NB, with M0 < (M1=M2) (M1 = 49.8±12.2g N/day and M2 = 52.5±14.0g N/day). Protein catabolism rate was similarly kept among diets. Thus, the results of the NB and 15 N-glycine kinetics indicate that the recommended protein intake for these athletes is higher than the one for seden...

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“…Toward the end of his time in Dundee, Mike began to think about aging and the loss of muscle size and strength with sarcopenia (72). He was particularly interested in reports in humans and animals of reduced postprandial stimulation of MPS through reduced sensitivity toward AAs in the aging muscle.…”

Section: Anabolic Resistance With Aging Disuse Atrophy and The Inflmentioning

confidence: 99%

Michael John Rennie, MSc, PhD, FRSE, FHEA, 1946–2017: an appreciation of his work on protein metabolism in human muscle

Millward

Halliday

Hundal

et al. 2017

The American Journal of Clinical Nutrition

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Effects of ageing and human whole body and muscle protein turnover

Cited by 51 publications

References 61 publications

Essential Amino Acids Improve Insulin Activation of Akt/mTOR Signaling in Soleus Muscle of Aged Rats

Essential Amino Acids Improve Insulin Activation of Akt/mTOR Signaling in Soleus Muscle of Aged Rats

Efeito da oferta dietética de proteína sobre o ganho muscular, balanço nitrogenado e cinética da 15N-glicina de atletas em treinamento de musculação

Michael John Rennie, MSc, PhD, FRSE, FHEA, 1946–2017: an appreciation of his work on protein metabolism in human muscle

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