Characterization of New Human Models of Non-histaminergic Itch and Their Interaction With the TRPM8 Receptor
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 20
- 试验地点
- 1
- 主要终点
- Superficial blood perfusion
研究概览
简要总结
In this experiment the investigators would like to test a new new human itch model based on papain, and to characterize the sensory quality and temporary aspects of papain skin prick test (SPT) in comparison to the inactivated-cowhage delivery system.
详细描述
The most used model of non-histaminergic itch is cowhage but this models presents several problems, such us the impossibility of standardizing the amount of the spicules inserted in the skin and the difficulty of obtaining the substance. These aspects bring us the necessity to find a new and more standardized model of non-histaminergic itch.
Papain is a cysteine protease extracted from papaya plant that is known to cause itch if applied to the skin. For these reasons the investigators would like to test a new new human itch model based on papain, and to characterize the sensory quality and temporary aspects of papain skin prick test (SPT) in comparison to the inactivated-cowhage delivery system.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 18 Years 至 60 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy men and women
- •18-60 years
- •Speak and understand English
排除标准
- •Pregnancy or lactation
- •Drug addiction defined as any use of cannabis, opioids or other addictive drugs
- •Previous or current history of neurological, dermatological, immunological musculoskeletal, cardiac disorder or mental illnesses that may affect the results (e.g. neuropathy, muscular pain in the upper extremities, etc.).
- •Lack of ability to cooperate
- •Current use of medications that may affect the trial such as antihistamines, antipsychotics and pain killers, as well as systemic or topical steroids.
- •Skin diseases
- •Moles, scars or tattoos in the area to be treated or tested.
- •Hypersensitivity to papaya and mango fruit, cashew nuts, rubber latex
- •Consumption of alcohol or painkillers 24 hours before the study days and between these
- •Acute or chronic pain
- •Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical trials)
研究组 & 干预措施
Papain dosage
In the 1st session, each of the middle forearms of the subject will be divided into two squared areas (4x4 cm). The two areas will be located 4 cm apart. Three areas will be exposed to 10, 50 or 100 µg of papain, while the last area will be used as control (exposed to a vehicle).
干预措施: Papain 10 µg (Drug)
Papain dosage
In the 1st session, each of the middle forearms of the subject will be divided into two squared areas (4x4 cm). The two areas will be located 4 cm apart. Three areas will be exposed to 10, 50 or 100 µg of papain, while the last area will be used as control (exposed to a vehicle).
干预措施: Papain 50 µg (Drug)
Papain dosage
In the 1st session, each of the middle forearms of the subject will be divided into two squared areas (4x4 cm). The two areas will be located 4 cm apart. Three areas will be exposed to 10, 50 or 100 µg of papain, while the last area will be used as control (exposed to a vehicle).
干预措施: Papain 100 µg (Drug)
Papain dosage
In the 1st session, each of the middle forearms of the subject will be divided into two squared areas (4x4 cm). The two areas will be located 4 cm apart. Three areas will be exposed to 10, 50 or 100 µg of papain, while the last area will be used as control (exposed to a vehicle).
干预措施: Vehicle (Other)
Papain SPT
Each forearm of the subject will be divided into two squared areas (4x4 cm). The provocations of three areas will be performed with 100 µg of papain by SPT lancets. To assess the potential importance of repeated pricks, papain will be applied by 1, 5 or 25 SPT pricks thought the skin. The last area will be exposed to cowage spicules (made chemically inert by autoclaving) soaked in 5 mg/ml papain solution.
干预措施: Papain 1 SPT (Drug)
Papain SPT
Each forearm of the subject will be divided into two squared areas (4x4 cm). The provocations of three areas will be performed with 100 µg of papain by SPT lancets. To assess the potential importance of repeated pricks, papain will be applied by 1, 5 or 25 SPT pricks thought the skin. The last area will be exposed to cowage spicules (made chemically inert by autoclaving) soaked in 5 mg/ml papain solution.
干预措施: Papain 5 SPT (Drug)
Papain SPT
Each forearm of the subject will be divided into two squared areas (4x4 cm). The provocations of three areas will be performed with 100 µg of papain by SPT lancets. To assess the potential importance of repeated pricks, papain will be applied by 1, 5 or 25 SPT pricks thought the skin. The last area will be exposed to cowage spicules (made chemically inert by autoclaving) soaked in 5 mg/ml papain solution.
干预措施: Papain 25 SPT (Drug)
Papain SPT
Each forearm of the subject will be divided into two squared areas (4x4 cm). The provocations of three areas will be performed with 100 µg of papain by SPT lancets. To assess the potential importance of repeated pricks, papain will be applied by 1, 5 or 25 SPT pricks thought the skin. The last area will be exposed to cowage spicules (made chemically inert by autoclaving) soaked in 5 mg/ml papain solution.
干预措施: Cowhage (Other)
结局指标
主要结局
Superficial blood perfusion
时间窗: 15 minutes
Superficial blood perfusion is measured by a Speckle contrast imager (FLPI, Moor Instruments, England).
Measuring itch intensity by computerized Visual Analog Scale Scoring
时间窗: 15 minutes
The subjects will rate the sensation of itch on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates "no itch" and 100 indicates "worst itch imaginable" and similarly for sensations of stinging/pricking and burning, both of which are frequently associated with the sensation of itch.
Measuring pain intensity by computerized Visual Analog Scale Scoring
时间窗: 15 minutes
The subjects will rate the sensation of pain on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates "no pain" and 100 indicates "worst pain imaginable".
Measuring Alloknesis
时间窗: 15 minutes
Alloknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 milliNewton of force). This stimulator is applied 0.5 cm outside the area of itch provocation.
次要结局
- Measurement of Pain to Supra-threshold Heat Stimuli(15 minutes)
- Measurement of Mechanical Pain Thresholds (MPT)(15 minutes)
- Touch Pleasantness (TP)(15 minutes)
- Measurement of Warm Detection Thresholds (WDT)(15 minutes)
- Measurement of Heat Pain Thresholds (HPT)(15 minutes)
- Measurement of Cold Detection Thresholds (CDT)(15 minutes)
- Measurement of Cold Pain Thresholds (CPT)(15 minutes)
- Measurement of Mechanical Pain Sensitivity (MPS)(15 minutes)
研究者
Silvia Lo Vecchio
PhD, Assistant Professor
Aalborg University