Plasma Trimethylamine N-oxide Elevation Induced by L-carnitine Supplementation and Insulin Resistance

NCT05251207 — Not applicable, Completed, 40 participants, Poznan University of Physical Education

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The Role of Gut Microbiota Metabolite, Trimethylamine N-oxide, in the Insulin Resistance Development

RegistryNCT05251207, acronym MR
StatusCompleted
PhaseNot applicable
Study typeInterventional; randomized, parallel, masking: double, prevention
Enrollment40 (Actual)
SponsorPoznan University of Physical Education (Other)
ConditionsInsulin Resistance
InterventionsL-carnitine, L-leucine, Change of the circadian cycle (Dietary supplement, behavioral)
Datesstart 2022-02-07, primary completion 2026-05-31, completion 2026-08-13, first posted 2022-02-22, last updated 2026-08-17
Locations1 site in Poland

Related Papers Related Patents Related Grants Related Experts
All trials for Insulin Resistance All trials of L-carnitine All trials of L-leucine

-Summary

The primary aims of the current study:

* using L-carnitine supplementation modulate the level of plasma trimethylamine N-oxide to assess its effect on circulating cytokines related to diabetes and metabolic syndrome;
* using simulated night-shift work intervention as a stress factor, explore the effect of circulating metabolites on insulin sensitivity

The secondary aim is to evaluate the effect of carnitine supplementation on gut microbiome composition.

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+Detailed description

Subjects will be randomly divided in two groups: supplemented by L-carnitine 2g/day for 12 weeks, and placebo group receiving leucine in identical gelatine capsules.

Subjects who successfully complete the protocol will be divided into four subgroups - two with a changed circadian cycle and two controls (supplemented and placebo). Subgroups with a changed daily cycle will be able to sleep between 8:00 and 17:00 for four consecutive days, while during the night they will stay active in the laboratory. The oral glucose tolerance test (OGTT) will be performed before and after the circadian cycle modification. Glucose levels will be monitored by FreeStyle Libre Sensor. Moreover, the activity of the participants will be monitored by wearable activity trackers.

Before supplementation, as well as before circadian cycle modification and after finishing the whole experimental procedure, fasting blood samples will be collected for determination of plasma trimethylamine N-oxide (TMAO), trimethylamine (TMA), carnitine (free and acyl derivatives), protein markers of diabetes and inflammation.

Moreover, the stool samples will be collected before and after 12 weeks of supplementation, to determine the composition of the gut microbiome. In addition diet of participants will be monitored.

+Arms and interventions

ArmTypeInterventionsDescription
carnitineExperimentalDietary Supplement: L-carnitine; Behavioral: Change of the circadian cycle2 grams of L-carnitine per day for 12 weeks
leucinePlacebo comparatorDietary Supplement: L-leucine; Behavioral: Change of the circadian cycle2 grams of L-leucine per day for 12 weeks
modified circadian cycleExperimentalDietary Supplement: L-carnitine; Dietary Supplement: L-leucineno sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00).
normal circadian cycleActive comparatorDietary Supplement: L-carnitine; Dietary Supplement: L-leucinesleep at night for four consecutive days
  • L-carnitine (Dietary supplement): L-carnitine-L-tartrate
  • L-leucine (Dietary supplement): L-leucine
  • Change of the circadian cycle (Behavioral): Reducing sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00)

+Outcome measures

Primary outcomes

  • Circulating microbiome metabolites [13 weeks]: Determination of plasma trimethylamine and trimethylamine N-oxide using ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) method
  • Circulating carnitine metabolites [13 weeks]: Determination of plasma free, total, and acyl-L-carnitines using ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) method
  • Circulating diabetes biomarkers [13 weeks]: insulin, C-peptide, ghrelin, leptin, resistin using enzyme-linked immunosorbent assay
  • Circulating inflammatory biomarkers [13 weeks]: tumor necrosis factor, C-reactive protein using enzyme-linked immunosorbent assay
  • Oral Glucose Tolerance Test [1 week]: The subjects will consume 75 g of glucose solution drink within a 5-minute time frame. The glucose level will be continuously monitored with the FreeStyle Libre Sensor.

Secondary outcomes

  • gut microbiome composition [13 weeks]: 16 S rRNA sequencing will be used to analyze the gut microbiome in the stool samples

+Eligibility

Sex: All, ages: 20 Years to 30 Years, accepts healthy volunteers

Inclusion Criteria:

* healthy volunteers,
* must be able to swallow tablets

Exclusion Criteria:

* smokers,
* cardiovascular disease
* liver disease
* kidney disease
* gastrointestinal disorders (including stomach ulcers and erosions)
* diabetes

+Locations (1)

FacilityCityCountryStatus
Akademia Wychowania FizycznegoPoznanPoland

+Publications

  • Samulak JJ, Sawicka AK, Hartmane D, Grinberga S, Pugovics O, Lysiak-Szydlowska W, Olek RA. L-Carnitine Supplementation Increases Trimethylamine-N-Oxide but not Markers of Atherosclerosis in Healthy Aged Women. Ann Nutr Metab. 2019;74(1):11-17. doi: 10.1159/000495037. Epub 2018 Nov 28. PMID 30485835
  • Bescos R, Boden MJ, Jackson ML, Trewin AJ, Marin EC, Levinger I, Garnham A, Hiam DS, Falcao-Tebas F, Conte F, Owens JA, Kennaway DJ, McConell GK. Four days of simulated shift work reduces insulin sensitivity in humans. Acta Physiol (Oxf). 2018 Jun;223(2):e13039. doi: 10.1111/apha.13039. Epub 2018 Feb 12. PMID 29356345

+Investigators

  • Robert Olek, PhD, Principal investigator, Poznan University of Physical Education