ClinicalTrials.gg
CompletedNCT04791774PANINIUpdated Mar 10, 2021

Protein-bound Versus Free Amino Acid Nutrition During INtestinal Malabsorption in Critical Illness

An interventional study of Milk protein (food grade protein) and Fee amino acids (food grade amino acids) in Intestinal Malabsorption, Critical Illness and Protein Malnutrition, sponsored by Maastricht University Medical Center. Completed at 1 site in Netherlands. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2021-03-10.

Sponsored by Maastricht University Medical Center · Not applicable, Interventional, and Basic science

Phase
Not applicable
Study type
Interventional
Enrollment
16
Allocation
Randomized
Ages
18 Years to 75 Years
Sex
All
01

Study summary

In the current study, we willquantitate the difference in digestion and absorption kinetics of dietary whole protein versus free amino acids in vivo in critically ill patients admitted to the intensive care unit suffering from malabsorption. 16 adult, mechanically ventilated ICU patients with clinical signs of malabsorption (faecal weight >350 g/day) will be included. All patients will receive a primed continuous intravenous infusion of L-[ring2H5]-phenylalanine and L-[3,5-2H2]-Tyrosine for the duration of the study period. After reaching an isotopic steady state (1.5 hours), patients will receive either [1-13C]- phenylalanine labelled milk protein or free amino acids with an identical constitution and [1-13C]-phenylalanine.

Main study endpoint will be the splanchnic extraction of phenylalanine, calculated from systemic [1-13C]- and L-[ring2H5]-phenylalanine enrichment.

Read the detailed description

Background of the study:

The importance of the provision of sufficient protein in critical illness is increasingly recognized. Protein malabsorption seems to be an underestimated but substantial problem in critically ill patients, limiting the amount of this important nutrient that actually becomes available within the systemic circulation. Among several contributors to malabsorption in critical illness, exocrine pancreatic insufficiency has recently emerged as a regularly occurring phenomenon during critical illness. Pancreatic insufficiency could lead to reduced digestion and subsequent uptake of enteral provided proteins. A proposed solution to this problem could be the use of elementary feeds containing free amino acids instead of whole protein. Due to the lack of easy applicable and reproducible tests for protein malabsorption the true efficacy of these feeds is still unknown. We hypothesize that enteral nutrition containing free amino acids leads to higher systemic levels of amino acids and will therefore increase the amount of dietary amino acids available for protein synthesis.

Objective of the study:

To quantitate the difference in digestion and absorption kinetics of dietary whole protein versus free amino acids in vivo in patients admitted to the ICU suffering from malabsorption.

Study design:

Randomized, single-blind controlled, single-centre, intervention study.

Study population:

16 adult, mechanically ventilated ICU patients with clinical signs of malabsorption (faecal weight >350 g/day).

Intervention:

Normal enteral nutrition will be ceased 8 hours before the start of study participation. All patients will receive a primed continuous intravenous infusion of L-[ring2H5]-phenylalanine and L-[3,5-2H2]-Tyrosine for the duration of the study period. After reaching an isotopic steady state (1.5 hours), patients will receive either [1-13C]- phenylalanine labelled milk protein or free amino acids with an identical constitution and [1-13C]-phenylalanine.

Primary study parameters/outcome of the study:

Main study endpoint will be the splanchnic extraction of phenylalanine, calculated from systemic [1-13C]- and L-[ring2H5]-phenylalanine enrichment.

Secundary study parameters/outcome of the study:

Secondary endpoints include the impact of enteral nutrition on whole body protein balance, glucose and insulin concentrations and faecal energy and protein loss as a measure of malabsorption.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

Total study participation will take 16 hours, including 8 hours of fasting. Arterial blood samples will be collected regularly, with 50 ml of blood being sampled in total, amounting to a maximum of 1.0% of total circulating volume. All infusions, as well as blood sample collection, will be performed through indwelling catheters necessary for normal ICU treatment, meaning no lines or nasogastric tubes will have to be placed for the purposes of the study. Both isotopically labelled protein and free amino acids have been proven safe for use in humans and carry no harmful risks for the study participant. Changes in protein digestion, absorption and metabolism are specific to critical illness and their impact on the clinical condition and recovery of patients is severe. Investigating new strategies to modulate these effects are therefore essential, but require experimental studies in a vulnerable population. The risks in the present study are minimal whereas the results could help improve nutritional management in the intensive care.

02

Conditions studied

  • Intestinal Malabsorption
  • Critical Illness
  • Protein Malnutrition

Keywords

  • Proteins
  • Stable Isotopes
  • Enteral Nutrition
03

In context

Malabsorption Syndromes

54 studies on the registry are indexed under Malabsorption Syndromes; 12 are open to participants now.

This study's enrollment of 16 is below the median of 38 across 44 interventional studies indexed under Malabsorption Syndromes.

Browse Malabsorption Syndromes studies →

Lead sponsor

Maastricht University Medical Center is the lead sponsor of 853 studies on the registry; 114 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 75 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Age > 18 and \< 75 years
  2. Fecal weight > 350g/day
  3. Critical illness of any origin (e.g. medical, surgical, trauma) requiring admittance on ICU ward.
  4. Expected ICU stay for the duration of the study protocol
  5. Mechanically ventilated (PaO2/FiO2 ratio of >100 and \<300)
  6. Nasogastric tube in situ
  7. Receiving full enteral nutrition without gastric residual volumes
  8. Arterial (any location) line in situ
  9. Flexi-seal system in situ

Exclusion criteria

Exclusion Criteria:

  1. Proven (pre-existing) intestinal disease that potentially limits normal gut function and absorption of nutrients (e.g. IBD, short-bowel, entero-cutaneous fistulas including a surgical enterostomy)
  2. Proven (pre-existing) primary pancreatic disease or obstruction of the pancreatic duct of any origin (e.g. pancreatitis, carcinoma).
  3. Patients who are moribund (not expected to be in ICU for more than 48 hours due to imminent death)
  4. A lack of commitment to full aggressive care during the first week due to severity of illness, comorbidities and potential harm from maximal treatment (anticipated withholding or withdrawing treatments)
  5. Absolute to enteral nutrients (e.g., gastrointestinal [GI] perforation, obstruction or no GI tract access for any reason)
  6. Receiving parenteral nutrition.
  7. Nasoduodenal or nasojejunal feeding tube
  8. Renal dysfunction defined as a serum creatinine >171 umol/L or a urine output of less than 500 ml/last 24 hours
  9. Patients requiring chronic veno-venous hemofiltration
  10. Patients on ECMO/ELS
  11. Cirrhosis - class C/D liver disease
  12. Patients with primary admission diagnosis of burns (>30% body surface area)
  13. Weight less than 50 kg or greater than 100 kg
  14. Pregnant patients or lactating with the intent to breastfeed
  15. Previous randomization in this study
  16. Enrolment in any other interventional study
  17. Milk/lactose allergy
  18. Previous participation in a 13C amino acid tracer study within the last year
Terms in these criteria, in plain language(2)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

Child-Pugh class

A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.

05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Double (Participant, Care provider)
Enrollment
16 participants (actual)

Study arms

  • Active comparator
    Protein group

    Patients receive 20 grams of Intrinsically labelled milk protein.

    Dietary Supplement: Milk protein (food grade protein)

  • Experimental
    Free amino acid group

    Patients receive 20 grams of free amino acids equivalent to the milk protein labelled with 13C-Phenylalanine

    Dietary Supplement: Fee amino acids (food grade amino acids)

Interventions

  • Subjects will receive an enteral nutritional formula containing 20 grams intrinsically labeled (1-\[13C\]-phenylalanine) milk protein

    Also known as: Protein

  • Nutritional formula containing 20 grams of a free amino acid mixture equivalent in composition to the milk protein with 1-\[13C\]-labeled phenylalanine

    Also known as: Amino Acids

06

What researchers measure

Primary outcomes

  1. systemic availability of diet-derived amino acids

    The main study endpoint in this study is the systemic availability of enteral administered protein-bound or free amino acid nutrition, including the rate of appearance (Ra) of dietary derived phenylalanine. Modified Steele's equations will be applied to plasma enrichments of L-\[ring-2H5\]-phenylalanine, L-\[1-13C\]-phenylalanine enrichment, L-\[ring-2H4\]-tyrosine and L-\[3,5-2H2\]-tyrosine.

    Time frame: 8 hours

Secondary outcomes

  1. Total plasma amino acids (AAmax [μmol/L])

    Total plasma amino acids (AAmax \[μmol/L\])

    Time frame: 8 hours

  2. Plasma glucose (glucosemax [mmol/L])

    Plasma glucose (glucosemax \[mmol/L\])

    Time frame: 8 hours

  3. Plasma insulin (insulinmax [mU/L])

    Plasma insulin (insulinmax \[mU/L\])

    Time frame: 8 hours

  4. Intestinal absorption capacity (energy provided - fecal energy loss x 100%)

    Intestinal absorption capacity (energy provided - fecal energy loss x 100%)

    Time frame: 2 x 24 hours

  5. Fecal elastase (µg elastase / g feces)

    Fecal elastase (µg elastase / g feces)

    Time frame: 2 x 24 hours

  6. Fecal presence of L-[1-13C]-phenylalanine

    Fecal presence of L-\[1-13C\]-phenylalanine

    Time frame: 2x 12 hours

07

Study locations

1 site
  • Maastricht UMC+
    Maastricht, 6229HX, Netherlands
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Mar 10, 2021, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04791774
Collaborators
Maastricht University
Responsible party
Sponsor
First posted
Mar 10, 2021
Start date
Mar 27, 2018
Primary completion
Nov 30, 2019
Completion
Nov 30, 2019
Last update
Mar 10, 2021

Study contacts

Marcel van de Poll, MD, PhD
principal investigator · Maastricht University Medical Centre

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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Studies of the drug tested here: Amino Acids

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