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Aging Is Accompanied by a Blunted Muscle Protein Synthetic Response to Protein Ingestion.

Wall BT, Gorissen SH, Pennings B, Koopman R, Groen BB, Verdijk LB, van Loon LJ - PLoS ONE (2015)

Bottom Line: Post-absorptive muscle protein synthesis rates did not differ significantly between the young and older group.Post-prandial muscle protein synthesis rates were 16% lower in the older subjects when compared with the young.Aging is associated with the development of muscle anabolic inflexibility which represents a key physiological mechanism underpinning sarcopenia.

View Article: PubMed Central - PubMed

Affiliation: NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, 6200 MD, The Netherlands.

ABSTRACT

Purpose: Progressive loss of skeletal muscle mass with aging (sarcopenia) forms a global health concern. It has been suggested that an impaired capacity to increase muscle protein synthesis rates in response to protein intake is a key contributor to sarcopenia. We assessed whether differences in post-absorptive and/or post-prandial muscle protein synthesis rates exist between large cohorts of healthy young and older men.

Procedures: We performed a cross-sectional, retrospective study comparing in vivo post-absorptive muscle protein synthesis rates determined with stable isotope methodologies between 34 healthy young (22±1 y) and 72 older (75±1 y) men, and post-prandial muscle protein synthesis rates between 35 healthy young (22±1 y) and 40 older (74±1 y) men.

Findings: Post-absorptive muscle protein synthesis rates did not differ significantly between the young and older group. Post-prandial muscle protein synthesis rates were 16% lower in the older subjects when compared with the young. Muscle protein synthesis rates were >3 fold more responsive to dietary protein ingestion in the young. Irrespective of age, there was a strong negative correlation between post-absorptive muscle protein synthesis rates and the increase in muscle protein synthesis rate following protein ingestion.

Conclusions: Aging is associated with the development of muscle anabolic inflexibility which represents a key physiological mechanism underpinning sarcopenia.

No MeSH data available.


Graphical representation of the individual values for fractional mixed muscle protein synthesis rates (FSR), calculated using plasma L-[ring-2H5]phenylalanine enrichments as the precursor pool, in healthy young and elderly men in the post-absorptive state (n = 34 young and n = 72 elderly) and following the ingestion of 20 g protein (post-prandial; n = 35 young and n = 40 elderly).
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pone.0140903.g003: Graphical representation of the individual values for fractional mixed muscle protein synthesis rates (FSR), calculated using plasma L-[ring-2H5]phenylalanine enrichments as the precursor pool, in healthy young and elderly men in the post-absorptive state (n = 34 young and n = 72 elderly) and following the ingestion of 20 g protein (post-prandial; n = 35 young and n = 40 elderly).

Mentions: Interestingly, if it is assumed that 12 h of each day is spent under post-absorptive and 12 h under post-prandial conditions, the amount of muscle tissue synthesized per day taking account of lean body mass of the subjects can be calculated. In this regard, an equivalent amount of daily muscle protein is synthesized under post-absorptive conditions per day between young and older subjects (21±2 and 24±2 g, respectively; P>0.05). However, under post-prandial conditions, younger subjects synthesized considerably more than the elderly (36±2 and 28±2 g, respectively; P<0.001). When post-absorptive and post-prandial muscle protein synthesis rates for young and older men were expressed per kg lean body mass, no differences in post-absorptive muscle protein synthesis rates were observed but older subjects displayed 30% lower post-prandial muscle protein synthesis rates compared with the young (P<0.01). Moreover, when adjusted for lean body mass, only the young cohort demonstrated a significantly greater (65%) muscle protein synthetic response to protein feeding when compared with basal (P<0.001). Fig 3 illustrates the individual values of post-absorptive and post-prandial muscle protein synthesis rates for young and older men. In addition, we examined the relationship between post-absorptive muscle protein synthesis rates and the magnitude of increase following protein ingestion where both measurements had been made in an individual during a single visit (Fig 4). Regardless of age, a strong negative correlation (r = -0.70; P<0.001) was observed between basal muscle protein synthesis rates and the magnitude of stimulation following protein ingestion. Similar correlations were observed within the young and elderly sub-groups separately (r = -0.81 and r = -0.66, respectively; both P<0.0001). These correlations were also evident when muscle protein synthesis rates adjusted for lean body mass were used.


Aging Is Accompanied by a Blunted Muscle Protein Synthetic Response to Protein Ingestion.

Wall BT, Gorissen SH, Pennings B, Koopman R, Groen BB, Verdijk LB, van Loon LJ - PLoS ONE (2015)

Graphical representation of the individual values for fractional mixed muscle protein synthesis rates (FSR), calculated using plasma L-[ring-2H5]phenylalanine enrichments as the precursor pool, in healthy young and elderly men in the post-absorptive state (n = 34 young and n = 72 elderly) and following the ingestion of 20 g protein (post-prandial; n = 35 young and n = 40 elderly).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4633096&req=5

pone.0140903.g003: Graphical representation of the individual values for fractional mixed muscle protein synthesis rates (FSR), calculated using plasma L-[ring-2H5]phenylalanine enrichments as the precursor pool, in healthy young and elderly men in the post-absorptive state (n = 34 young and n = 72 elderly) and following the ingestion of 20 g protein (post-prandial; n = 35 young and n = 40 elderly).
Mentions: Interestingly, if it is assumed that 12 h of each day is spent under post-absorptive and 12 h under post-prandial conditions, the amount of muscle tissue synthesized per day taking account of lean body mass of the subjects can be calculated. In this regard, an equivalent amount of daily muscle protein is synthesized under post-absorptive conditions per day between young and older subjects (21±2 and 24±2 g, respectively; P>0.05). However, under post-prandial conditions, younger subjects synthesized considerably more than the elderly (36±2 and 28±2 g, respectively; P<0.001). When post-absorptive and post-prandial muscle protein synthesis rates for young and older men were expressed per kg lean body mass, no differences in post-absorptive muscle protein synthesis rates were observed but older subjects displayed 30% lower post-prandial muscle protein synthesis rates compared with the young (P<0.01). Moreover, when adjusted for lean body mass, only the young cohort demonstrated a significantly greater (65%) muscle protein synthetic response to protein feeding when compared with basal (P<0.001). Fig 3 illustrates the individual values of post-absorptive and post-prandial muscle protein synthesis rates for young and older men. In addition, we examined the relationship between post-absorptive muscle protein synthesis rates and the magnitude of increase following protein ingestion where both measurements had been made in an individual during a single visit (Fig 4). Regardless of age, a strong negative correlation (r = -0.70; P<0.001) was observed between basal muscle protein synthesis rates and the magnitude of stimulation following protein ingestion. Similar correlations were observed within the young and elderly sub-groups separately (r = -0.81 and r = -0.66, respectively; both P<0.0001). These correlations were also evident when muscle protein synthesis rates adjusted for lean body mass were used.

Bottom Line: Post-absorptive muscle protein synthesis rates did not differ significantly between the young and older group.Post-prandial muscle protein synthesis rates were 16% lower in the older subjects when compared with the young.Aging is associated with the development of muscle anabolic inflexibility which represents a key physiological mechanism underpinning sarcopenia.

View Article: PubMed Central - PubMed

Affiliation: NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, 6200 MD, The Netherlands.

ABSTRACT

Purpose: Progressive loss of skeletal muscle mass with aging (sarcopenia) forms a global health concern. It has been suggested that an impaired capacity to increase muscle protein synthesis rates in response to protein intake is a key contributor to sarcopenia. We assessed whether differences in post-absorptive and/or post-prandial muscle protein synthesis rates exist between large cohorts of healthy young and older men.

Procedures: We performed a cross-sectional, retrospective study comparing in vivo post-absorptive muscle protein synthesis rates determined with stable isotope methodologies between 34 healthy young (22±1 y) and 72 older (75±1 y) men, and post-prandial muscle protein synthesis rates between 35 healthy young (22±1 y) and 40 older (74±1 y) men.

Findings: Post-absorptive muscle protein synthesis rates did not differ significantly between the young and older group. Post-prandial muscle protein synthesis rates were 16% lower in the older subjects when compared with the young. Muscle protein synthesis rates were >3 fold more responsive to dietary protein ingestion in the young. Irrespective of age, there was a strong negative correlation between post-absorptive muscle protein synthesis rates and the increase in muscle protein synthesis rate following protein ingestion.

Conclusions: Aging is associated with the development of muscle anabolic inflexibility which represents a key physiological mechanism underpinning sarcopenia.

No MeSH data available.