Use of Endogenous Melatonin and 6-hydroxymelatonin as Biomarkers for CYP1A2

Study Overview
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Brief Summary
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An observational study comprising 4 sessions will be conducted in 12 healthy volunteers. During each study session (sessions 1 to 4), a 12-hour urine collection during the night (21h-9h) will be carried out by each participant. The first urine in the morning will be collected separately to be analysed independently of the 12-hour collection. 24 hours before the start of the night urine collection, volunteers will be asked to refrain from consuming alcohol and caffeinated drinks/foods, with the exception of session 3. Conversely, in session 3, subjects will be asked to drink or eat caffeinated food/drinks 24 hours prior to night-time urine collection (at least one cup of coffee or a can of Coca-Cola®). After each 12-hour urine collection (around 9:00 a.m.), subjects will be given a cup of coffee or a can of Coca-Cola®. Capillary blood samples (10 μL) will be taken from the fingertips 2 hours after the coffee or Coca-Cola®.

Official Title
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Use of Endogenous Melatonin and 6-hydroxymelatonin as Biomarkers for CYP1A2

Conditions
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Healthy

Intervention / Treatment
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* Other: Session 1 (day 1)
* Other: Session 2 (day 3)
* Other: Session 3 (day 15)
* Other: Session 4 (day 30)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy men and women Understanding of French language and ability to give a written informed consent Exclusion Criteria: Inability to refrain from alcohol or methylxanthine-containing beverages and foods for 24 hours Sensitivity to coffee or CocaCola® Irregular (i.e. non-daily or inconstant dosages) intake of medication or food of a CYP1A2 modulator (including tobacco)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Session 1 (day 1)|12 hours overnight urine (9 pm - 9 am) will be collected. First morning voids will be collected separately in order to be also analysed independently from the 12 hours collection. 24 hours before the 12 hours overnight urine collection, volunteers will be asked to refrain from alcohol consumption and methylxanthine-containing beverages and foods. After the 12-hour urine collection (around 9:00 a.m.), subjects will be given a cup of coffee or a can of Coca-Cola®. Capillary blood samples (10 μL) will be taken from the fingertips 2 hours after the coffee or Coca-Cola®.|
|Other: Session 2 (day 3)|12 hours overnight urine (9 pm - 9 am) will be collected. First morning voids will be collected separately in order to be also analysed independently from the 12 hours collection. 24 hours before the 12 hours overnight urine collection, volunteers will be asked to refrain from alcohol consumption and methylxanthine-containing beverages and foods. After the 12-hour urine collection (around 9:00 a.m.), subjects will be given a cup of coffee or a can of Coca-Cola®. Capillary blood samples (10 μL) will be taken from the fingertips 2 hours after the coffee or Coca-Cola®.|
|Other: Session 3 (day 15)|12 hours overnight urine (9 pm - 9 am) will be collected. First morning voids will be collected separately in order to be also analysed independently from the 12 hours collection. 24 hours before the 12 hours overnight urine collection, volunteers will be asked to drink or eat caffeinated food/drinks 24 hours prior to night-time urine collection (at least one cup of coffee or a can of Coca-Cola®). After the 12-hour urine collection (around 9:00 a.m.), subjects will be given a cup of coffee or a can of Coca-Cola®. Capillary blood samples (10 μL) will be taken from the fingertips 2 hours after the coffee or Coca-Cola®.|
|Other: Session 4 (day 30)|12 hours overnight urine (9 pm - 9 am) will be collected. First morning voids will be collected separately in order to be also analysed independently from the 12 hours collection. 24 hours before the 12 hours overnight urine collection, volunteers will be asked to refrain from alcohol consumption and methylxanthine-containing beverages and foods. After the 12-hour urine collection (around 9:00 a.m.), subjects will be given a cup of coffee or a can of Coca-Cola®. Capillary blood samples (10 μL) will be taken from the fingertips 2 hours after the coffee or Coca-Cola®.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Validation LC-MS/MS analytical method | Validation of the LC-MS/MS analytical method for simultaneous quantification of endogenous melatonin and 6-hydroxymelatonin in urine samples | 1 month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intra- and inter-variability | Assess intra- and inter-variability of the urinary metabolic ratio (UMR) 6-hydroxymelatonin/melatonin at three different time (day 1, day 4 and day 30) | 3 days (day 1, day 4 and day 30) | 
| Urine correlation | Assess correlation between 12 hours overnight urine and first morning voids samples | 4 days (day 1, day 4, day 15 and day 30) | 
| Correlation melatonin and caffeine | Assess correlation between the endogenous UMR 6-hydroxymelatonin/melatonin and the paraxanthine/caffeine ratio in dried blood spot (DBS) | 4 days (day 1, day 4, day 15 and day 30) | 
| Impact caffeine intake | Assess impact of caffeine intake on the UMR 6-hydroxymelatonin/melatonin (day 15) before and after caffeine abstinence (fold-change measurements) | 1 day (day 15) |