Maintenance of the musculoskeletal mass by control of protein turnover: the concept of anabolic resistance and its relevance to the transplant recipient.
Level 5 - mechanism / opinion, no new human data
Narrative review and mechanistic reasoning without primary data or systematic search methodology.
What was done
This narrative review synthesized physiological mechanisms regulating muscle protein synthesis and breakdown in response to nutrition (essential amino acids and insulin) and exercise. It applied the concept of "anabolic resistance" to pre- and post-organ transplant populations and considered the potential confounding effects of immunosuppressive medications.
What was found
The abstract provides no empirical numbers or quantitative data. It describes that muscle protein synthesis is primarily controlled by essential amino acids and stimulated additively by exercise, while protein breakdown is regulated by insulin. It notes that conditions such as aging, immobilization, and chronic organ disease lead to blunted feeding responses (anabolic resistance), which likely persists in transplant recipients and may be counteracted by exercise but hindered by drugs like sirolimus, cyclosporine, and corticosteroids.
Why it matters
The paper frames muscle wasting in transplantation as a functional resistance to anabolic feeding cues rather than simple malnutrition, suggesting that rehabilitation strategies require combined exercise and targeted nutritional regimens to overcome signaling deficits.
Limits
This is a narrative review presenting mechanistic theory without original empirical data or systematic review methodology. The abstract provides no sample sizes, clinical trials, or quantitative effect sizes, and its therapeutic predictions for transplant recipients require prospective verification.
Cited by
- supports Michael Rennie's research group was the first to define the concept of anabolic resistance.