PP264 - DUODENAL MUCOSAL PROTEIN TURNOVER EXCEEDS 16% PER DAY IN VIVO IN BOTH YOUNG AND OLDER ADULTS

PP264

DUODENAL MUCOSAL PROTEIN TURNOVER EXCEEDS 16% PER DAY IN VIVO IN BOTH YOUNG AND OLDER ADULTS

L. Kuin^1,2,*, J. Senden¹, A. Overman¹, J. Goessens¹, E. Kornips¹, A. Holwerda¹, G. van Lieshout^1,3, K. Lenaerts⁴, W. Wodzig⁵, D. Keszthelyi², D. Jonkers², L. van Loon¹

¹Department of Human Biology, ²Department of Gastroenterology-Hepatology, Maastricht University Medical Centre+, Maastricht, ³FrieslandCampina, Amersfoort, ⁴Department of Surgery, ⁵Central Diagnostic Laboratory, Maastricht University Medical Centre+, Maastricht, Netherlands

Rationale: All human organ tissues are in a constant state of turnover, regulated by the balance between protein synthesis and breakdown rates. The intestine is one of the more highly regenerative organs in the human body. So far, no data are available on duodenal tissue protein turnover rates under free-living conditions in humans. The aim of this study was to assess daily duodenal mucosal protein synthesis rates under free-living conditions in vivo in young and older adults.

Methods: In this cross-sectional, non-therapeutic intervention design, 24 healthy young (n=12, 5M/7F; age 26±5 y; BMI 24.3±4.4 kg/m²) and older (n=12, 7M/5F; age 74±5 y; BMI 24.4±2.9 kg/m²) males and females consumed a two-day standardized diet (8.9±1.5 MJ; 15 energy% provided as protein). Deuterium oxide (²H₂O) ingestion with frequent saliva and blood sampling were applied to assess body water ²H and serum [²H]-alanine enrichments, respectively. Duodenal biopsies were obtained during gastroduodenoscopy to allow assessment of duodenal mucosal protein synthesis rates throughout the two-day assessment period. Data were analyzed by independent samples t-tests.

Results: Daily integrated duodenal mucosal protein synthesis rates averaged 16.8±2.7 %/day, ranging between 13.4 and 24.3 %/day, with serum [²H]-alanine enrichments as precursor pool enrichment. Duodenal mucosal protein synthesis rates averaged 16.5±2.6 and 17.2±2.9 %/day in young and older adults, respectively, with no differences between groups (P=0.54).

Conclusion: Duodenal mucosal protein synthesis rates exceed 16 %/day under free-living conditions in vivo in both healthy young and older adults. Age does not seem to impact daily duodenal mucosal protein synthesis rates in healthy adults.

Disclosure of Interest: L. Kuin Grant / Research Support from: Funding of this research was obtained from FrieslandCampina (Amersfoort, the Netherlands) as part of the Topsector Agri&Food (Project LWV21.052). , Other: Received research grants, consulting fees, speaking honoraria, or a combination of these for research on the impact of exercise and nutrition on muscle metabolism. A full overview on research funding is provided at: https://www.maastrichtuniversity.nl/l.vanloon, J. Senden: None declared, A. Overman: None declared, J. Goessens: None declared, E. Kornips: None declared, A. Holwerda: None declared, G. van Lieshout Other: Employee of FrieslandCampina, K. Lenaerts: None declared, W. Wodzig: None declared, D. Keszthelyi Other: Received research funding from Horizon 2020, Horizon Europe, Dutch Foundation for Gastroenterology and Rome Foundation, and speaker’s fee from Rome Foundation (paid to host institute)., D. Jonkers Other: Received funding from public-private partnership grants of Top Knowledge Institute (TKI) Agri&Food and Health Holland, by Organic A2BV/Mothersfinest BV, the Dutch Digestive Health Fund, and by H2020 DISCOvERIE/848228., L. van Loon Other: Received research grants, consulting fees, speaking honoraria, or a combination of these for research on the impact of exercise and nutrition on muscle metabolism. A full overview on research funding is provided at: https://www.maastrichtuniversity.nl/l.vanloon