Autofluorescent Flavoprotein Imaging of Intraepidermal Nerve Fibers: a Pilot Study
Palabras clave
Abstracto
Descripción
The first aim of the current project is to test the precision of AFI in the epidermis of 10 healthy volunteers. For this purpose, a range of nociceptive electrical stimuli with increasing intensities (5Hz @ 0.5mA-1.0mA) and one innocuous control stimulus (2000Hz @1mA) will be delivered to the third finger of each subject. The outcome measure is AFI-intensity, which is the change in autofluorescence intensity compared to baseline (delta F/F). The standard deviation of AFI intensity will be the measure of precision. Pearson's correlation coefficient will be calculated between electrical stimulus intensities and AFI intensity. A linear correlation needs to be confirmed, since this is a general characteristic of AFI. A paired t-tests will be performed to compare AFI intensities following 5Hz @ 1mA stimulation and 2000Hz @ 1mA stimulation. Lidocaine/prilocaine cream will be applied to the fingertips of the subjects and the electrical stimuli will be repeated, to serve as a negative control experiment. A repeated-measures ANOVA will be performed to compare AFI intensities before and after application of lidocaine/prilocaine cream.
The second aim of our study is to validate AFI in experimentally induced small nerve fiber degeneration of the epidermis, by comparing AFI intensities in subjects before and one week after application of a 8% capsaicin patch to the third fingertip. A repeated-measures ANOVA will be performed to compare AFI intensities before and after capsaicin-induced small nerve fiber degeneration. Assuming that all subjects develop epidermal small fiber degeneration following the 8% capsaicin patch, a statistically significant difference in AFI intensity would serve as a proof-of-principle and would provide validity to autofluorescent flavoprotein imaging of epidermal nociceptor activity as a diagnostic test for SFN. Comparing the distributions of before and after capsaicin-induced small nerve fiber degeneration will lead to a probability estimation of having SFN based on the outcome measure, i.e. AFI intensity. In future research, false-positive and false-negative consequences will be evaluated, leading to cut-off values in patients suspected for SFN.
fechas
| Verificado por última vez: | 01/31/2019 |
| Primero enviado: | 08/21/2015 |
| Inscripción estimada enviada: | 08/31/2015 |
| Publicado por primera vez: | 09/01/2015 |
| Última actualización enviada: | 05/31/2019 |
| Última actualización publicada: | 06/10/2019 |
| Fecha de los primeros resultados enviados: | 01/29/2018 |
| Fecha de los primeros resultados de CC enviados: | 02/17/2019 |
| Fecha de los primeros resultados publicados: | 06/02/2019 |
| Fecha de inicio real del estudio: | 08/31/2015 |
| Fecha estimada de finalización primaria: | 06/30/2016 |
| Fecha estimada de finalización del estudio: | 08/31/2016 |
Condición o enfermedad
Intervención / tratamiento
Device: AFI intensity in healthy volunteers
Device: negative control 1: lidocaine/prilocaine
Device: negative control 2: 8% capsaicin
Fase
Grupos de brazos
| Brazo | Intervención / tratamiento |
|---|---|
| Experimental: AFI intensity in healthy volunteers 10 healthy volunteers, on whose 3rd fingertips AFI intensity is measured through an AFI microscope | Device: AFI intensity in healthy volunteers measurement of AFI intensities following increasing nociceptive stimulus intensities |
| Active Comparator: negative control 1: lidocaine/prilocaine 10 healthy volunteers, on whose 3rd fingertips AFI intensity is measured through an AFI microscope, 1hour after application of lidocaine/prilocaine creme (negative control 1) | Device: negative control 1: lidocaine/prilocaine measurement of AFI intensities following lidocaine/prilocaine cream |
| Active Comparator: negative control 2: 8% capsaicin -10 healthy volunteers, on whose 3rd fingertips AFI intensity is measured through an AFI microscope, 1week after application of an 8% capsaicin patch (negative control 2) | Device: negative control 2: 8% capsaicin measurement of AFI intensities following 8% capsaicin patch |
Criterio de elegibilidad
| Edades elegibles para estudiar | 18 Years A 18 Years |
| Sexos elegibles para estudiar | All |
| Acepta voluntarios saludables | si |
| Criterios | Inclusion Criteria: - healthy volunteers Exclusion Criteria: - younger than 18 years - pre-existing neuropathy - previous allergic reaction to local anaesthetics |
Salir
Medidas de resultado primarias
1. AFI-intensity After Nociceptive Stimulation [Day 1, T=0h (AFI measurements), Day 1, T=6h (AFI measurements after lidocaine/prilocaine), Day 7 (AFI measurements after capsaicin)]
