Breath Metabolomics of Placebo Effects, a Pilot Study

Study Overview
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Brief Summary
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This study is to analyze the breath metabolome before and after the administration of a placebo in an established experimental pain procedure in healthy subjects in order to investigate placebo effects, and whether they induce any measurable changes at the metabolic level.

Detailed Description
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Interrogation of the exhaled breath metabolome will be performed by using an objective method of measurement for placebo effects in pain analgesia, known as Cold Pressure Test (CPT). CPT reactions can be measured objectively by blood pressure spikes as well as changes in continuous heart rate monitoring.To this end, probands will be continuously connected to a Heartrate & Blood Pressure Monitor. First, baseline exhalation will be assessed. Then, the CPT is performed according to the 'CPT Guide' with subsequent post-pain exhalations analysis with or without self-administration of the placebo (NaCl nasal spray). After 15 minutes rest, probands will be submitted to a second post-pain exhalations set (+/- placebo). The process is completely non-invasive as the participant just exhales through a commercially available disposable bacterial/viral filter coupled to the ion source.

Official Title
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Breath Metabolomics of Placebo Effects Via Cold Pressor Test

Conditions
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Analgesia

Intervention / Treatment
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* Other: Cold Pressor Test (CPT)
* Other: Placebo NaCl Nasal spray


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy female and male adult volunteers German speaking, or good knowledge of the German language Able to understand the study Able to give informed consent Exclusion criteria: Regularly taking medication potentially interfering with pain sensation (analgesics, antihistamines and calcium and potassium channel blockers) Current pregnancy Daily smokers (as per WHO definition: A daily smoker is someone who smokes any tobacco product at least once a day.) Neuropathy Chronic pain Neuromuscular or psychiatric disease Known or suspected heart, kidney or liver disease Hypertension (Systolic (mmHg) >130, Diastolic (mmHg) >80) History of fainting or seizures History of Frostbite Current medications (psychoactive medication, narcotics, intake of analgesics) or being currently in psychological or psychiatric treatment.

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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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Single centered; national ,randomized, crossover, pilot study
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: CPT first<br>Cold Pressor Test (CPT): apparatus for the task is a tank of water of temperature of 4 °C (+-0.5 °C), with instruction to immerse the hand until too uncomfortable to continue. A maximum time limit per immersion of 3-5 min is applied. Quantitative measurement can then be made of pain threshold (point first perceived as painful) and tolerance time. All 20 participants will undergo two study visits. The order in which they will receive CPT and CPT plus placebo differs, with participants being randomly split into two groups. 10 participants first CPT + placebo and then CPT, and 10 participants vice versa. | Other: Cold Pressor Test (CPT)<br>* Cold Pressor Test (CPT): apparatus for the task is a tank of water of temperature of 4 °C (+-0.5 °C), with instruction to immerse the hand until too uncomfortable to continue. A maximum time limit per immersion of 3-5 min is applied. Quantitative measurement can then be made of pain threshold (point first perceived as painful) and tolerance time.<br>Other: Placebo NaCl Nasal spray<br>* placebo nasal spray containing NaCl solution<br>|
| Other: CPT+placebo first<br>Participant will be told and read about the 'pain medication' (= Placebo NaCl Nasal spray). Thereafter participant will self-administer a nasal spray, which is in fact a placebo nasal spray containing NaCl solution and Cold Pressor Test (CPT) is performed. All 20 participants will undergo two study visits. The order in which they will receive CPT and CPT plus placebo differs, with participants being randomly split into two groups. 10 participants first CPT + placebo and then CPT, and 10 participants vice versa | Other: Cold Pressor Test (CPT)<br>* Cold Pressor Test (CPT): apparatus for the task is a tank of water of temperature of 4 °C (+-0.5 °C), with instruction to immerse the hand until too uncomfortable to continue. A maximum time limit per immersion of 3-5 min is applied. Quantitative measurement can then be made of pain threshold (point first perceived as painful) and tolerance time.<br>Other: Placebo NaCl Nasal spray<br>* placebo nasal spray containing NaCl solution<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in signal intensity of mass-to-charge ratio (m/z) of exhaled metabolites | The variable of primary interest is the variation of signal intensity of mass-to-charge ratio (m/z) of exhaled metabolites. | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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pain, placebo effects, analgesia, placebo analgesia, cold pressor test, breath metabolomics