Testing the Potential Metabolic Effect of the Human Gut Bacterial Peptide, RUCILP, in Healthy Men

The goal of this randomized, double-blinded and placebo-controlled clinical cross-over trial is in healthy men to explore the potential metabolic effects of the naturally occurring gut bacterial polypeptide, RUCILP. This bacterial peptide is produced by commensal strains of Ruminococcus torques in the human gut microbiota.

In preclinical studies of rodents, RUCILP lowers blood glucose and stimulates release of plasma insulin, glucagon-like peptide-1(GLP-1) and Peptide YY (PYY) but induces a decline of glucose-dependent insulinotropic polypeptide (GIP).

In the present trial, the investigators want to explore potential effects of intraduodenally delivered RUCILP on release of plasma concentrations of GLP-1, GIP and PYY.

In addition, the investigators will test for potential effects of intestinal RUCILP infusion on plasma concentrations of glucose, insulin and metabolome.

Participants will have a duodenal tube placed into which RUCILP or placebo will be infused over 3 hours after an initial standardized liquid meal infusion into the duodenal tube.

Participants will on different days and in a randomized order receive either placebo or RUCILP infusion into the tube.

Safety is acutely monitored under the intervention and postintervention safety is monitored by clinical biochemistry measures of hematology, and liver and kidney functions. The study participants will further keep a diary of any experienced adverse effects during the week after the intervention.

Primary OUTCOMES: a composite of changes in plasma concentrations of GLP-1, GIP and PYY.

Secondary OUTCOMES: changes in plasma glucose, plasma insulin and plasma metabolome profile.

Study Overview

• Status: Active, not recruiting
• Conditions: Healthy Male Adults
• Intervention / Treatment: Other: Placebo; Biological: Test bacterial peptide: RUCILP

• Study Type: Interventional
• Enrollment (Estimated): 15
• Phase: Phase 1

Contacts and Locations

Study Locations

• Denmark
  • Hellerup, Denmark, 2900
    • Gentofte Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age between 18 and 35 years
• Self-reported good health
• Caucasian
• Normal body mass index (18.5 to <25)

Exclusion Criteria:

• Any known disorder/disease that could interfere with study results or is seen as compromising to the study (as assessed by the investigator), for example diabetes, cancer or cardiovascular or kidney disease.
• Use of any daily medication as well as p.r.n. (pro re nata; not taken regularly) medication that cannot be discontinued during the trial
• Use of antibiotics during the recent three months
• Acute or chronic gastrointestinal symptoms
• Lactose intolerance
• Smoking
• Alcohol or drug abuse
• Use of creatine as dietary supplement during study period
• Plasma creatinine concentration above the normal range (>105 μmol/L)
• Known significant liver disease or plasma ALAT concentration ≥ 3 × normal value
• Values for hemoglobin, leukocytes, or thrombocytes outside of the normal ranges

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; Placebo comparator that is identical to the active arm except for the absence of RUCILP	Other: Placebo; Placebo is identical to the active intervention except for the absence of the RUCILP molecule.
Active Comparator: Active; Intervention is identical to the placebo arm except for the addition of RUCILP to the infusion.	Biological: Test bacterial peptide: RUCILP; The naturally occuring gut peptide RUCILP synthesized by the commensal gut bacterium Ruminococcus torques

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma concentrations of GIP	Plasma measurements of GIP at different time points during the study day.	During the 3 hours of RUCILP/placebo infusion
Plasma concentrations of GLP-1	Plasma measurements of GLP-1 at different time points during the study day.	During the 3 hours of RUCILP/placebo infusion
Plasma concentrations of PYY	Plasma measurements of PYY at different time points during the study day.	During the 3 hours of RUCILP/placebo infusion

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma concentrations of insulin	Plasma measurements of insulin at different time points during the study day.	During the 3 hours of RUCILP/placebo infusion
Plasma concentrations of glucose	Plasma measurements of glucose at different time points during the study day.	During the 3 hours of RUCILP/placebo infusion
Plasma metabolome profile	Plasma metabolome profile at different time points during the study day.	During the 3 hours of RUCILP/placebo infusion
Plasma concentrations of RUCILP	Plasma measurements of RUCILP at different time points during the study day.	During the 3 hours of RUCILP/placebo infusion

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood leukocytes	Concentration of leukocytes in blood	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Blood eosinophils	Concentration of eosinophils in blood	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Total blood leukocytes	Concentration of total leukocytes in blood	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Blood neutrophils	Concentration of neutrophils in blood	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Blood platelets	Concentration of platelets in blood	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Blood hemoglobin	Concentration of hemoglobin in blood	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma alanine transaminase (ALT)	Concentration of alanine transaminase (ALT) in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma aspartate transferase (AST)	Concentration of aspartate transferase (AST) in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma alkaline phosphatase	Concentration of alkaline phosphatase in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma albumin	Concentration of albumin in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma creatinine	Concentration of creatinine in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Estimated Glomerular Filtration Rate (eGFR)		At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma sodium	Concentration of sodium in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma potassium	Concentration of potassium in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma calcium (total)	Concentration of total calcium in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma phosphate	Concentration of phosphate in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma creatine kinase	Concentration of creatine kinase in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Plasma C-reactive protein	Concentration of C-reactive protein in plasma	At baseline, at 180 minutes, and at follow-up (4-8 days after study day)
Experienced adverse effects post infusion	Number of experienced adverse effects as noted in a diary at end of each study day.	At 180 minutes.
Experienced adverse effects during the four days following an infusion	Number of experienced adverse effects as noted in a diary during four days of follow-up after each infusion.	During four days of follow-up after each study day.

Collaborators and Investigators

• Sponsor: Oluf Pedersen

Study record dates

Study Major Dates

• Study Start (Actual): July 28, 2025
• Primary Completion (Actual): August 27, 2025
• Study Completion (Estimated): April 1, 2026

Study Registration Dates

• First Submitted: March 20, 2025
• First Submitted That Met QC Criteria: April 4, 2025
• First Posted (Actual): April 11, 2025

Study Record Updates

• Last Update Posted (Estimated): October 3, 2025
• Last Update Submitted That Met QC Criteria: September 29, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: Metabolism; Intervention study; Postbiotics; Ruminococcus torques; Plasma insulin; Plasma glucose; Duodenal infusion; Gut bacterial peptide; Intestinal infusion; Plasma PYY; Plasma incretins; Plasma GIP; Plasma RUCILP; Plasma GLP-1
• Other Study ID Numbers: H-22011935

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Due to GDPR regulations we are unable to share IPD with other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No