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Published on: September 13, 2022
Altered Dynamics in Splanchnic Amino Acid Extraction During Early Sepsis Recovery in Pigs: Whole Body Compared with
Gabriella A M Ten Have1, John J Thaden1, Mariëlle P K J Engelen1
1Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX, United States.
Background:
Establishing the metabolic fate of nutrients from food intake is crucial for interpreting the benefits of food interventions. Using stable isotopes labeled amino acids (AA) such as L-phenylalanine (Phe) during feeding allows for the determination of first-pass splanchnic extraction (SPE) on a whole-body level (WbSPE). The relationship between this measure and the total fraction of food-derived Phe retained by the splanchnic area has not been validated.
Objective:
Therefore, we compared WbSPE with the enteral-derived Phe and actual PheSPE, measured by splanchnic-trans-organ fluxes in both healthy and early sepsis recovery states.
Methods:
In 25 catheterized healthy control or Pseudomonas-induced-septic pigs (±25 kg), primed-continuous intravenous infusions of L-[ring-D5]-Phe and continuous enteral infusion of an AA mixture (per kg/h: 0.031 g N, 0.78 g maltodextrin), containing L-[1-13C]-Phe, were administered for 6 h. We collected arterial, portal, and hepatic venous blood and measured plasma enrichments and tracee concentrations by liquid chromatography-mass spectrometry (LC-MS/MS). Statistical analysis was performed using GraphPad Prism. Best-fit group means from the last 3 h were compared using an unpaired t-test. The data are presented as mean [95% confidence interval].
Results:
In the healthy control group, WbSPE was 38[16,61]% (P<0.0001) of the enteral-derived Phe SPE and tended to be 16[-1,34]% (P=0.0761) higher than the actual Phe tracee SPE. However, WbSPE was the same as first-pass SPE. In the septic group, WbSPE was increased 29[8,50]%, (P=0.001) whereas the actual Phe tracee SPE remained unchanged, whereas portal-drained viscera fluxes showed a diminished release of enteral-derived tracee Phe (P < 0.0001).
Conclusions:
WbSPE reflects first-pass SPE rather than enteral-derived tracee SPE or the actual SPE. Our observations suggest that whole-body level calculated SPE may be challenged in estimating food-derived amino acid SPE in response to steady meal intake. During early sepsis recovery, less AA are absorbed, and this changes the dynamics between first-pass and the actual SPE.
