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Desensitization of Nociceptive Afferents by Application of Topical Capsaicin, Trans-cinnamaldehyde and L-menthol

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ClinicalTrials.gov Identifier: NCT03132142
Recruitment Status : Unknown
Verified April 2017 by Hjalte Holm Andersen, Aalborg University.
Recruitment status was:  Recruiting
First Posted : April 27, 2017
Last Update Posted : April 27, 2017
Sponsor:
Information provided by (Responsible Party):
Hjalte Holm Andersen, Aalborg University

Brief Summary:
The purpose of this study is to investigate the potential desensitising effects of repeated applications of capsaicin, trans-cinnamaldehyde and L-menthol on thermal, mechanical and chemical sensory stimulations.

Condition or disease Intervention/treatment Phase
Pain Pruritus Neuropathic Pain Dermatology/Skin - Other Drug: Capsaicin Drug: Trans-cinnamaldehyde Drug: L-Menthol Drug: Vehicle patch Not Applicable

Detailed Description:

Capsaicin, the compound responsible for the pungency of chili peppers, can induce desensitization to nociceptive (1) and pruriceptive (2) stimuli when topically applied. The purpose of this study is to determine whether repeated topical applications of trans-cinnamaldehyde and L-menthol result in decreased responses to various nociceptive and non-nociceptive thermal and mechanical stimuli and to compare potential alterations with those caused by repeated topical application of capsaicin. Furthermore, this study investigates the temporal profile of said alterations.

Capsaicin 8% patches, trans-cinnamaldehyde 10%, L-menthol 40% and inert vehicle patches will each be applied to 4 4x4 cm predefined areas on the skin of the volar forearms for 1 hour 4 times on 4 consecutive days. Before each application and the day after the last application, cold detection threshold (CDT), warmth detection threshold (WDT), cold pain threshold (CPT) and heat pain threshold (HPT) will be assessed using a Medoc Pathway (Medoc, Israel) equipped with a 3x3 cm contact thermode. On the last day, mechanical detection threshold (MDT) is assessed using a series of von Frey filaments and mechanical pain threshold (MPT) and mechanical pain sensitivity (MPS) is assessed using a series of standardized pinprick stimulators (Aalborg University).

Furthermore, full-field laser perfusion imaging (FLPI) will be used to assess the degree of neurogenic inflammation in each predefined area before and after each substance application and at the last session.

  1. F. Henrich et al. 2015 "Capsaicin-sensitive C- and A-fibre nociceptors control long-term potentiation-like pain amplification in humans"
  2. H.H. Andersen et al. 2017 "Antipruritic effect of pretreatment with 8% topical capsaicin on histamine- and cowhage-evoked itch in healthy volunteers - a randomized placebo-blinded proof-of-concept trial"

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 22 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Participant)
Primary Purpose: Basic Science
Official Title: Temporal Profile of the Nociceptive Desensitization Induced by 8% Topical Capsaicin and the Functional Independence of Transient Receptor Potential Ankyrin 1 (TPRA1)- and Vanilloid 1 (TRPV1)-Expressing Nociceptive Afferents
Estimated Study Start Date : April 2017
Estimated Primary Completion Date : August 2017
Estimated Study Completion Date : August 2017

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: Capsaicin
Capsacin (8%) patches applied topically 4 times for 1 hour to a 4x4 cm predefined area on the skin of the volar forearms.
Drug: Capsaicin
4x4 cm patch of 8% topical capsaicin applied to the skin of the volar forearm for 1 hour 4 times on 4 consecutive days

Experimental: Trans-cinnamaldehyde
Trans-cinnamaldehyde (10%, dissolved in 90% ethanol) applied topically 4 times for 1 hour to a 4x4 cm predefined area on the skin of the volar forearms on a cotton ball placed in a plastic chamber to limit evaporation.
Drug: Trans-cinnamaldehyde
1mL of 10% trans-cinnamaldehyde applied to the skin of the volar forearm for 1 hour 4 times on 4 consecutive days

Experimental: L-menthol
L-menthol (40%, dissolved in 96% ethanol) applied topically 4 times for 1 hour to a 4x4 cm predefined area on the skin of the volar forearms on a cotton ball placed in a plastic chamber to limit evaporation.
Drug: L-Menthol
1mL of 40% L-menthol applied to the skin of the volar forearm for 1 hour 4 times on 4 consecutive days

Placebo Comparator: Vehicle patch
Inert vehicle patches applied topically 4 times for 1 hour to a 4x4 cm predefined area on the skin of the volar forearms.
Drug: Vehicle patch
Inert vehicle patch applied to the skin of the volar forearm for 1 hour 4 times on 4 consecutive days




Primary Outcome Measures :
  1. Cold Pain Threshold (CPT) [ Time Frame: Assessed at 5 visits on 5 consecutive days ]
    The pain threshold for cold stimulation assessed using a Medoc Pathway (Medoc, Israel) equipped with a 3x3 cm thermode. CPT is defined as the temperature at which cold induces pain and is expressed in °C.

  2. Heat Pain Threshold (HPT) [ Time Frame: Assessed at 5 visits on 5 consecutive days ]
    The pain threshold for heat stimulation


Secondary Outcome Measures :
  1. Neurogenic Inflammation Intensity [ Time Frame: Assessed before and after application of substances at 5 visits on 5 consecutive days ]
    The average intensity of the neurogenic inflammation as assessed by full-field laser perfusion imaging (FLPI) (expressed in arbitrary units)

  2. Neurogenic Inflammation Area [ Time Frame: Assessed before and after application of substances at 5 visits on 5 consecutive days ]
    The area of the neurogenic inflammation as assessed by full-field laser perfusion imaging (FLPI) (expressed in arbitrary units)

  3. Pain During Application of Capsaicin [ Time Frame: Assessed every 5 minutes during the 60 minute application of capsaicin at 4 visits on 4 consecutive days ]
    Pain during the 60 minute application of topical capsaicin as rated on a visual analog scale (VAS) (0-10)

  4. Pain During Application of Trans-cinnamaldehyde [ Time Frame: Assessed every 5 minutes during the 60 minute application of trans-cinnamaldehyde at 4 visits on 4 consecutive days ]
    Pain during the 60 minute application of trans-cinnamaldehyde as rated on a visual analog scale (VAS) (0-10)

  5. Pain During Application of L-menthol [ Time Frame: Assessed every 5 minutes during the 60 minute application of L-menthol at 4 visits on 4 consecutive days ]
    Pain during the 60 minute application of L-menthol as rated on a visual analog scale (VAS) (0-10)

  6. Pain During Application of Inert Patch (Control) [ Time Frame: Assessed every 5 minutes during the 60 minute application of the inert patch (control) at 4 visits on 4 consecutive days ]
    Pain during the 60 minute application of the inert patch (control) as rated on a visual analog scale (VAS) (0-10)

  7. Cold Detection Threshold (CDT) [ Time Frame: Assessed at 5 visits on 5 consecutive days ]
    The detection threshold for cold stimulation assessed using a Medoc Pathway (Medoc, Israel) equipped with a 3x3 cm thermode. CDT is defined as the temperature at which cold can be detected and is expressed in °C.

  8. Warmth Detection Threshold (WDT) [ Time Frame: Assessed at 5 visits on 5 consecutive days ]
    The detection threshold for warmth stimulation assessed using a Medoc Pathway (Medoc, Israel) equipped with a 3x3 cm thermode. WDT is defined as the temperature at which warmth can be detected and is expressed in °C.

  9. Mechanical Detection Threshold (MDT) [ Time Frame: Assessed at day 5 (final visit) ]
    The detection threshold for mechanical stimulation is defined as the smallest force that can be felt and is assessed using a series of standardized von Frey filaments and using the "method of limits" employing a series of stimulations with ascending and descending force expressed in mN.

  10. Mechanical Pain Threshold (MPT) [ Time Frame: Assessed at day 5 (final visit) ]
    The pain threshold for mechanical stimulation is defined as the smallest force that induces pain and is assessed using a series of standardized pinprick stimulators (Aalborg University) and using the "method of limits" employing a series of stimulations with ascending and descending forces expressed in mN.

  11. Mechanical Pain Sensitivity (MPS) [ Time Frame: Assessed at day 5 (final visit) ]
    The sensitivity to mechanically induced pain induced by a series of 7 standardized pinprick stimulators (Aalborg University) as rated on a visual analog scale (VAS) ranging from 0-10 with 0 representing no pain and 10 representing the worst pain imaginable.

  12. Vibration Detection Threshold [ Time Frame: Assessed at day 5 (final visit) ]
    The detection threshold for vibrational stimulation assessed using a Vibrameter (Somedic, Sweden).



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Healthy
  • Speaks and understands English or Danish
  • 18-60 years

Exclusion Criteria:

  • Pregnancy or lactation
  • Drug addiction
  • Previous or current dermatological, neurological, musculoskeletal or mental illnesses
  • Lack of ability to cooperate
  • Current use of medications that may affect the trial

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03132142


Contacts
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Contact: Lars Arendt-Nielsen, Professor 0045 99408830 lan@hst.aau.dk

Locations
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Denmark
SMI Recruiting
Aalborg, Denmark, 9000
Contact: Hjalte H Andersen, MSc. Med.    0045 24464515    hha@hst.aau.dk   
Sub-Investigator: Jens B Marker, BSc. Med.         
Sponsors and Collaborators
Aalborg University

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Responsible Party: Hjalte Holm Andersen, MSc. Med., Phd. Stud., Aalborg University
ClinicalTrials.gov Identifier: NCT03132142    
Other Study ID Numbers: N-20170018
First Posted: April 27, 2017    Key Record Dates
Last Update Posted: April 27, 2017
Last Verified: April 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Neuralgia
Pruritus
Peripheral Nervous System Diseases
Neuromuscular Diseases
Nervous System Diseases
Pain
Neurologic Manifestations
Signs and Symptoms
Skin Diseases
Skin Manifestations
Cinnamic aldehyde
Capsaicin
Menthol
Antipruritics
Dermatologic Agents
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Antineoplastic Agents, Phytogenic
Antineoplastic Agents
Antimutagenic Agents
Protective Agents