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Enrolling by Invitation

NCT Number: NCT03511846

Pain Biomarker Study

This study investigates molecular and physical biomarkers of headaches in order to better understand mechanisms of these diseases.

There are 3 main parts:

1. Use of capsaicin (active ingredient in hot chili peppers) to trigger release of calcitonin gene related peptide - the hypothesis is that this will be different in headache subjects compared to controls (and if so might be used to predict how these patients will respond to certain medications that modulate calcitonin gene-related peptide). Subjects will be given capsaicin as a cream applied to the forehead or the inner nostril, or a hot sauce that is ingested. 2. Use of capsaicin to trigger eye watering - the hypothesis is that oxygen gas will slow down the amount of eye watering. Cluster headache patients respond very powerfully to oxygen gas but to very little else. The mechanism for oxygen is unknown but in rodents there is data that it works on the parasympathetic / lacrimal gland system. This study translates rodent data into humans in a non-invasive way to confirm the mechanism of this very effective treatment. 3. Use of ice water to trigger headaches - brain freeze causes a very short-lived but intense headache that may cause similar biomarker release as other headache disorders. This may be a useful human model for other headache disorders.

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Key information

Conditions

Migraine Brain Diseases Central Nervous System Diseases Cluster Headache Headache Disorders Headache Disorders, Primary Hemicrania Continua Lacerations Migraine Disorders Nervous System Diseases Paroxysmal Hemicrania SUNCT Short-Lasting Unilateral Neuralgiform Headache With Conjunctival Injection and Tearing Trigeminal Autonomic Cephalalgias Trigeminal Autonomic Cephalgia Wounds and Injuries

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

The University of Texas Health Science Center at Houston

Houston, Texas, 77030, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of one of the following: a. Diagnosis of a primary headache disorder according to the International Headache Classification, including migraine with aura, migraine without aura, chronic migraine, tension headache, cluster headache, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA), and hemicrania continua; b. Diagnosed by a pain medicine physician with lumbar radiculopathy (possibly including neuropathic features, nerve impingement on MRI, or electromyography (EMG) report suggestive of lumbar radiculopathy); or c. Healthy control subject with no history of debilitating headaches or debilitating back pain / radiculopathy pain, and no headaches or back pain within the previous 3 months.
  • Able to provide HIPAA authorization to share prior medical records/imaging
  • Age 18 and older

Exclusion criteria

  • The following items exclude the subject from all portions of the study: a. Known history of cardiovascular or neurovascular diseases. These diseases may include carotid stenosis of >50%, vertebral stenosis, peripheral vascular disease, angina or myocardial infarction, stroke, or vascular malformations; b. History of brain tumors or epilepsy; c. Active pregnancy or lactation; d. Daily cigarette, tobacco or nicotine use; e. Life expectancy less than 1 year, co-existing disease or other characteristic that precludes appropriate diagnosis of headache or spine pain; f. Active drug / alcohol use or dependence that, in the opinion of the investigator, would interfere with adherence to study requirements; or g. Inability or unwillingness of subject to give informed consent (e.g., ward of the state)
  • The following items exclude the subject only from the capsaicin portion of the study: a. Known allergy to capsaicin or hot peppers
  • The following items exclude the subject only from the oxygen portion of the study: a. Pulmonary or other non-headache diseases that require the use of supplemental oxygen
  • The following items exclude the subject only from the cold water irrigation (ice water) portion of the study: a. Trauma, fractures, or congenital abnormalities of the soft palate

Treatment and study plan

Oral capsaicin

Drug

Subjects will drink a solution with capsaicin

Topical Capsaicin

Drug

Capsaicin cream will be applied to the skin of the forehead, cheek, or leg

Intranasal capsaicin

Drug

Capsaicin cream will be applied to the nostril

Cold Water Irrigation

Other

Subjects will be asked to drink up to 2000 ml of cold water or ice water (temperature 0-10 degrees Celsius) as fast as possible, either continuously or intermittently (i.e. 200-800 ml at a time)

Medical Air

Other

Subjects will be exposed to medical air

Low Flow Oxygen

Drug

Subjects will be exposed to oxygen gas between 1-9 L/min

High Flow Oxygen

Drug

Subjects will be exposed to oxygen gas between 10-25 L/min

Primary outcomes

  1. Activation of trigeminoautonomic reflex as assessed by change in Calcitonin gene-related peptide (CGRP) levels from before stimulation to after stimulation.

    Time frame: 10 minutes before pain stimulation and 10 minutes, 20 minutes, 30 minutes, 60 minutes, and 90 minutes after pain stimulation

  2. Activation of trigeminoautonomic reflex as assessed by tear fluid production

    Time frame: 90 minutes after pain stimulation

    The amount of tear fluid after each intervention will be measured via Schirmer strips

Secondary outcomes

  1. Activation of trigeminoautonomic reflex as assessed by change in pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) levels levels from before stimulation to after stimulation.

    Time frame: 10 minutes before pain stimulation and 10 minutes, 20 minutes, 30 minutes, 60 minutes, and 90 minutes after pain stimulation

  2. Activation of trigeminoautonomic reflex as assessed by saliva production

    Time frame: 90 minutes after pain stimulation

  3. Activation of trigeminoautonomic reflex as assessed by nasal fluid production

    Time frame: 90 minutes after pain stimulation

  4. Activation of trigeminoautonomic reflex as assessed by tactile threshold measurement with von Frey Filaments

    Time frame: 90 minutes after pain stimulation

  5. Activation of trigeminoautonomic reflex as assessed by dermal blood flow

    Time frame: 90 minutes after pain stimulation

Sponsors and collaborators

Lead sponsor

The University of Texas Health Science Center, Houston

Other

Collaborators

  • University of California, San Francisco

Registry information

Official study title

The Pain Biomarker Study: Changes in Circulating Pain Signalling Molecules With Activation of Pain Receptors

Acronym: PBS

Important dates

Study start
2018
Primary completion
2028
Study completion
2028
First posted
Apr 30, 2018
Registry last updated
Feb 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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