Challenging the Inflammatory Response System in Insomnia Disorder

Study Overview
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Brief Summary
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The main purpose of this study is to understand how insomnia (compared to good sleep) may affect the response of the body to a repeated physiological challenge, such as inserting the hand in ice-cold water for several times in a row. In particular, the investigators are interested in the response of markers that can be associated with stress, such as blood pressure and stress hormones.

Detailed Description
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Sleep is critical for the regulation and maintenance of biological systems, and sleep deficiency, such as insomnia, has been shown to be associated with elevated risks for cardiovascular, metabolic, and mood disorders. Despite the high prevalence of insomnia in the population, the investigators understanding of the biological consequences of the disorder with respect to inflammatory, autonomic, and stress system markers is limited, and often not consistent. In addition, insomnia may not only alter the basal activity of these systems, but may change their reactivity to other stressors and challenges. In support of this assumption are findings showing that poor sleep quality in healthy individuals is associated with a stronger biological response to a stressful challenge, such as the cold pressor test. This test involves the immersion of the hand in ice-cold water. It is one of the most commonly used laboratory physiological challenge tests, provoking not only unpleasantness, but also increases in stress and inflammatory markers. Investigations of such system's reactivity to challenge may elucidate systems abnormalities that the investigators do not capture by only assessing basal system's levels. For example, in patients with rheumatoid arthritis, basal inflammatory levels are normal, but the response to a physiological stress challenge (cold pressor test) is amplified. To the investigators knowledge, no studies have measured how insomnia may affect the reactivity of biological systems to a stressful challenge, which may serve as an important indicator of system's dysregulation and associated disease risk. In this light, the primary goal of this proposal will investigate whether stress-related systems are more reactive to a physiological stressful challenge in insomnia disorder compared to healthy controls.

Official Title
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Challenging the Inflammatory Response System: Are Individuals With Insomnia More Reactive?

Conditions
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Insomnia

Intervention / Treatment
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* Behavioral: Cold Pressor Test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Women and men between the ages 18-55 years Blood chemistry in the normal range BMI less than or equal to 35 Specific to insomnia group: Diagnosis of insomnia disorder based on DSM-V criteria Specific for control group: Good quality and quantity sleep Exclusion Criteria: Active infection/disease. History of neurological, chronic pain, immune, cardiovascular, liver/kidney, or metabolic disorder History of psychiatric disorders within the last 6 months prior to study start Sleep disorders other than insomnia Reynaud's disease Psychotropic, sleep, or any other medications or herbs interfering with the inflammatory, autonomic, or HPA system in the last 2 weeks prior to study start, except oral contraceptives In psychotherapy or any other behavioral interventions at study start Donation of blood or platelets within 3 months of hospital visits Pregnant/nursing. Substance abuse.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Insomnia Disorder<br>Testing reactivity of stress-related systems to repeated exposure to the cold pressor test (hand immersion into ice-cold water) among participants with a clinical diagnosis of insomnia disorder. | Behavioral: Cold Pressor Test<br>* Repeated immersion of hand in ice-cold water<br>|
| Healthy Control<br>Testing reactivity of stress-related systems to repeated exposure to the cold pressor test (hand immersion into ice-cold water) among healthy participants without a diagnosis of insomnia disorder. | Behavioral: Cold Pressor Test<br>* Repeated immersion of hand in ice-cold water<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inflammatory Response to Physiological Challenge- Change in Plasma Levels of IL-6 | Inflammatory marker: Change in plasma levels of IL-6 (pg/mL). | Baseline blood was obtained between 11am-12pm and prior to any Cold Pressor Tests (CPTs). Three CPTs were performed, with 1.5 hours between each one. The first CPT was done at 1pm. Blood draws were obtained 20min and 50 min after each CPT. | 
| Stress Reactivity to Physiological Challenge- Change in Serum Levels of Cortisol | HPA marker: Change in serum cortisol levels (ug/dL) | Baseline blood was obtained between 11am-12pm and prior to any Cold Pressor Tests (CPTs). Three CPTs were performed, with 1.5 hours between each one. The first CPT was done at 1pm. Blood draws were obtained 20min and 50 min after each CPT. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glucocorticoid Sensitivity- Percentage of IL-6 Positive Monocytes | Percentage of IL-6 positive monocytes following stimulation with LPS (100pg/mL) and varying concentrations of Dexamethasone | Monocytes are only obtained from the baseline blood draw, which occurs at 11am. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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insomnia, inflammation, stress