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Completed

NCT Number: NCT06127693

Childhood Adversity, Inflammatory Reactivity and Persistent Pain

The goal of this observational study is to investigate how adverse experiences during childhood are linked to people experiencing persistent pain and fatigue in adulthood.

The questions the investigators aim to answer are:

1. Does participant-reported childhood adversity predict levels of IL-6 and TNF-α after in vitro provocation of whole blood using endotoxin? 2. Do levels of IL-6 and TNF-α after in vitro immune provocation using endotoxin predict vulnerability to persistent pain and fatigue after in vivo immune provocation (tetravalent influenza vaccine)? 3. Do levels of IL-6 and TNF-α after in vitro immune provocation using endotoxin predict vulnerability to persistent pain and fatigue after in vivo neural provocation?

For this study, the investigators will recruit and enrol 96 healthy human adults (18 - 65 years old) with a range of adverse experiences during childhood. Participants will attend 2 study sessions during which the investigators will take a sample of blood, assess pressure pain threshold before and after cold water immersion, assess heart rate variability, and assess the surface area of secondary skin hypersensitivity after electrical stimulation. At the end of the first session, participants will receive the influenza vaccination.

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Key information

Conditions

Chronic Pain Adverse Childhood Experiences Central Sensitisation Hyperalgesia Immune Response Nervous System Diseases Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Sensation Disorders Signs and Symptoms Somatosensory Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

University of Cape Town

Cape Town, Western Cape, 7701, South Africa

About this study

Background

Adverse experiences during childhood (childhood adversity) are associated with an increased risk of persistent pain and fatigue in adulthood. While the physiological relationships that link childhood adversity, persistent pain, and fatigue are unclear, all three factors are each associated with heightened innate immune and neural responses in adulthood. As such, neuroimmune interactions could underlie the relationship between childhood adversity, persistent pain, and fatigue, although the balance between the immune and neural influences likely varies across individuals.The investigators hypothesise that childhood adversity influences persistent pain and fatigue by priming: 1) immune, 2) neural, or 3) both systems, within an individual. Although previous studies have examined either immune or neural processes representing vulnerability to persistent pain and fatigue, the investigators are not aware of any study that has investigated both systems in the same cohort.

Methods

96 healthy adult humans with a range of childhood adversity history will undergo psychophysical testing before and after in vivo neural provocation (high frequency electrical stimulation) and, separately, immune provocation (influenza vaccine). Study proxies for vulnerability to persistent pain are surface area of secondary skin hypersensitivity induced by neural provocation and change in conditioned pain modulation after immune provocation; the proxy for vulnerability to fatigue is heart rate variability 24h after immune provocation. Immune responsiveness is represented by IL-6 and TNF-α levels in supernatant after in vitro lipopolysaccharide provocation of whole blood. The investigators hypothesise that levels of IL-6 and TNF-α after in vitro immune provocation will be positively associated with the area of secondary skin hypersensitivity after in vivo neural provocation, and negatively associated with conditioned pain modulation after in vivo immune provocation.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Between the ages of 18 and 65 years old.

Exclusion criteria

  • Incompetence to consent and participate, e.g. acute psychosis or high suicide risk.
  • Pregnancy,
  • Electrical implants (e.g. pace-maker),
  • Metal implants in the forearm,
  • Tattoos on the forearm,
  • Any visible injury or open wounds in the forearm,
  • Known history of allergic reactions to vaccines,
  • Has received the current season's influenza vaccine,
  • Chronic pain (pain on most days for the past 3 months),
  • Diabetes Mellitus,
  • Peripheral vascular disease,
  • Sensory impairment in the forearm, shoulder and lower back,
  • Use of medication that could later skin sensitivity (e.g. analgesic medication, immune modulators, topical medical creams),
  • Cardiovascular disorders,
  • Medication that alters immune function (e.g. NSAIDs, steroids),
  • Smoking habit,
  • Febrile illness in the preceding 4 weeks.

Treatment and study plan

Tetravalent Influenza Vaccine

Drug

All participants will receive the tetravalent influenza vaccine

Other names: flu vaccine

High-frequency electrical stimulation

Behavioral

All participants will receive High-frequency electrical stimulation

Primary outcomes

  1. Childhood Trauma Questionnaire-Short form

    Time frame: Baseline

    The Childhood Trauma Questionnaire-Short form uses 28 statements to probe five domains: emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect. Participants rate the extent to which each of the 28 possible situations was true during their childhood and adolescence, on a 5-point Likert scale ranging from "never true" to "very often true". The total score is computed by summing scores across forward- and reverse-coded items and a separate denial score that is obtained using three of the items. A higher score indicates more childhood adversities (i.e. worse outcome). The investigators will use the total score on the Childhood Trauma Questionnaire-Short to recruit specifically for a varied range in childhood adversity history and enrol participants into three similarly sized groups: 1) minimal childhood adversity (control) (score 25-36), 2) moderate childhood adversity (score 37-67), and 3) severe childhood adversity (score > 67).

  2. Provoked inflammatory response

    Time frame: Baseline

    Mean z-scores of IL-6 and TNF-alpha levels

  3. Secondary hypersensitivity (surface area)

    Time frame: 30 minutes, 45 minutes and 60 minutes after the high-frequency electrical stimulation (neural provocation)

    Surface area of secondary hypersensitivity induced by high-frequency electrical stimulation

  4. Conditioned pain modulation

    Time frame: Baseline and 24 hours after the influenza vaccine (immune provocation).

    Change in pressure pain threshold (test stimulus) after cold water immersion (conditioning stimulus)

  5. Temporal summation

    Time frame: Baseline and 24 hours after the influenza vaccine (immune provocation).

    Mechanical stimuli will be provided from a 256mN von Frey Filament. Participants will provide ratings to mechanical stimuli using the Sensation and Pain Rating Scale. The Sensation and Pain Rating Scale has a 'non-painful' range, on the left of the scale, ranging from -50 - "no sensation" to 0 - "the exact point at which what you feel transitions to pain". The 'painful' range, on the right of the scale, ranges from 0 to +50 - "most intense pain you can imagine". A lower score means less intense sensation/pain (i.e. better outcome) and a higher score means more intense sensation/pain (i.e. worse outcome).

Secondary outcomes

  1. Heart rate variability

    Time frame: Baseline, 40 minutes after the high-frequency electrical stimulation (neural provocation), and 24 hours after the influenza vaccine (immune provocation).

    Using 3-lead ECG and Biopac System

  2. N-back test

    Time frame: Baseline and 24 hours after the influenza vaccine (immune provocation).

    Assessing working memory

  3. 6-minute walk test

    Time frame: Baseline and 24 hours after the influenza vaccine (immune provocation).

    Assessing physical exertion and recovery

  4. Secondary hypersensitivity (magnitude)

    Time frame: Baseline, and 35 minutes, 50 minutes and 65 minutes after the high-frequency electrical stimulation (neural provocation).

    Change in ratings on the Sensation and Pain Rating Scale to punctate mechanical stimulation. The Sensation and Pain Rating Scale has a 'non-painful' range, on the left of the scale, ranging from -50 - "no sensation" to 0 - "the exact point at which what you feel transitions to pain". The 'painful' range, on the right of the scale, ranges from 0 to +50 - "most intense pain you can imagine". A lower score means less intense sensation/pain (i.e. better outcome) and a higher score means more intense sensation/pain (i.e. worse outcome).

  5. Static and dynamic light touch, and single electrical stimulation

    Time frame: Baseline, and 35 minutes, 50 minutes and 65 minutes after the high-frequency electrical stimulation (neural provocation)

    Change in ratings on the Sensation and Pain Rating Scale to punctate mechanical stimulation. The Sensation and Pain Rating Scale has a 'non-painful' range, on the left of the scale, ranging from -50 - "no sensation" to 0 - "the exact point at which what you feel transitions to pain". The 'painful' range, on the right of the scale, ranges from 0 to +50 - "most intense pain you can imagine". A lower score means less intense sensation/pain (i.e. better outcome) and a higher score means more intense sensation/pain (i.e. worse outcome).

Sponsors and collaborators

Lead sponsor

University of Cape Town

Other

Registry information

Official study title

The Roles of Childhood Adversity and Inflammatory Reactivity in Promoting Pain and Fatigue After Provocation

Acronym: CAIR

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
Nov 13, 2023
Registry last updated
Nov 13, 2023

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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