{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,29]],"date-time":"2026-10-29T11:09:46Z","timestamp":1793272186578,"version":"4.5.0"},"reference-count":30,"publisher":"Oxford University Press (OUP)","issue":"5","license":[{"start":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T00:00:00Z","timestamp":1771891200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000925","name":"National Health and Medical Research Council","doi-asserted-by":"publisher","award":["APP1144496"],"award-info":[{"award-number":["APP1144496"]}],"id":[{"id":"10.13039\/501100000925","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004267","name":"The Royal Adelaide Hospital","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004267","id-type":"DOI","asserted-by":"publisher"}]},{"name":"University of Adelaide Research Scholarship"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,5,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Rationale<\/jats:title>\n                    <jats:p>Critical illness impairs the muscle protein synthetic response to protein administration. Whether increased protein dose can overcome this anabolic resistance is unknown.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To assess the impact of a single intraduodenal bolus of 40\u2009g protein compared to 20\u2009g of protein in mechanically ventilated critically ill patients on the primary outcome of postprandial muscle protein synthesis rates.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Mechanically ventilated patients were randomized to 40 or 20\u2009g of whey protein isolate delivered intraduodenally over 1\u2009h. Primed continuous intravenous L-[ring-13C6]-phenylalanine and L-[3,5-2H2]-tyrosine infusions were applied with repeated arterial blood and skeletal muscle tissue sampling over 2\u2009h fasting and 6\u2009h postprandial periods to assess plasma amino acid responses and rates of fasting and postprandial muscle protein synthesis (primary outcome). Data are mean \u00b1 SD and area under the curve (AUC), analyzed with ANCOVA adjusted for fasting rate and paired t-tests (P &amp;lt; .05).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Measurements and main results<\/jats:title>\n                    <jats:p>Twenty patients (n = 10\/group: 40\u2009g: 90% male, 49 \u00b1 21\u2009y and 20\u2009g: 80% male, 51 \u00b1 13\u2009y) were studied. Postprandial muscle protein synthesis rates (primary outcome) did not differ between groups (40\u2009g vs 20\u2009g: 0.030 \u00b1 0.012 vs 0.025 \u00b1 0.010%\u00b7h\u22121; adjusted mean difference 0.007 (95% CI, \u22120.003 to 0.016) %\u00b7h\u22121; P = .152). Postprandial plasma leucine and tyrosine availability (AUC) were higher following 40\u2009g vs 20\u2009g protein (leucine: 263 \u00b1 87 vs 194 \u00b1 54\u2009\u00b5mol\u00b7L\u22121, P = .005; tyrosine: 92 \u00b1 24 vs 63 \u00b1 17\u2009\u00b5mol\u00b7L\u22121, P = .006). Fasting muscle protein synthesis rates did not differ between groups (40\u2009g vs 20\u2009g: 0.020 \u00b1 0.012 vs 0.025 \u00b1 0.023%\u00b7h\u22121; P = .558). The post hoc uncontrolled analysis of muscle protein synthesis rates from fasting to postprandial periods increased in the 40\u2009g group only (P = .005).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Higher enteral protein does not further augment postprandial muscle protein synthesis rates to overcome \u00adanabolic resistance during critical illness, despite increased plasma amino acid availability.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Trial Registration Number<\/jats:title>\n                    <jats:p>Australia New Zealand Clinical Trials Registry Identifier: ACTRN12620000776909.<\/jats:p>\n                  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