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Amino acids supplement improves muscle and gut function in critically ill patients

Rod Tucker
12 December, 2022  

An amino acids supplement enterally administered to critically ill patients resulted in an improvement of skeletal muscle and gut function

An amino acids supplement administered to critically ill patients improved twitch airway pressure and anterior quadriceps volume as well as gut functionality, according to the findings of a randomised, proof-of-concept trial by French researchers.

Critically ill patients such as those with sepsis, undergo dramatic depletion of lean body mass, particularly skeletal muscle, despite aggressive nutritional support. Moreover, this muscle wasting has clear and obvious implications for the patient’s recovery and rehabilitation, particularly in weaning them from the ventilator and their ability to resume normal life. In fact, critically ill patients show a signalling pathway activity directed towards stimulation of muscle protein synthesis and inhibited proteolysis. Other work has shown how this muscle wasting occurred early and rapidly during the first week and was more severe among those with multi-organ failure compared with single organ failure. Animal models of sepsis indicate that an amino acids (AAs) supplement is able to support the synthesis of vital proteins and to spare body protein catabolism during infection. However, evidence for the benefit of this approach in critically ill patients is sparse. For the present study, French researchers performed a randomised, double-blind, placebo-controlled study that included patients with sepsis or acute respiratory distress syndrome. These patients were given a specific combination of five amino acids (threonine, cysteine, proline, serine and leucine) or placebo mixed with enteral feeding for 21 days. Although there was no specific primary outcome set, researchers examined markers of renal function, gut barrier structure and functionality at baseline and 1, 2, 3 and 8 weeks after randomisation. Muscle structure and function were assessed through MRI measurements of the anterior quadriceps volume and by twitch airway pressure.

Amino acids supplement and muscle function

A total of 35 patients (mean age 71 years, 60.3% male) were included and randomised to either the amino acids (18) or placebo. For the amino acid group, all patients had sepsis, and this was also present the majority (88%) of placebo patients.

Use of the amino acids supplement did not impair urine output, blood creatinine levels or creatinine clearance. In addition, plasma citrulline levels (a measure of enterocyte functional mass and thus gut functionality) increased significantly in the amino acid group (mean difference, MD = 5.86, 95% CI 1.72 – 10, p = 0.007).

The mean difference (MD) in the anterior compartment of the quadriceps was significantly greater in the amino acid group (MD = 3.12, 95% CI 0.5 – 5.73, p = 0.0022). Similarly, the twitch airway pressure also increased in this group (MD = 10.6, 95% CI 0.99 – 20.20, p = 0.035). Taken together, the authors suggested that these data indicated that the extent of muscle catabolism was reduced when sufficient amino acids were provided.

The researchers concluded that enteral administration of AAs to critically ill patients increased plasma citrulline levels and improved twitch airway pressure and anterior quadriceps volume. They added that these results provided a rationale for further clinical investigation.

Heming N et al. Effect of an enteral amino acid blend on muscle and gut functionality in critically ill patients: a proof-of-concept randomized controlled trial. Crit Care 2022