Obstructive Sleep Apnea-induced Changes in Adipose and Liver Tissue and Effects of Massive Weight Loss on Inflammation

Investigation of Inflammation Induced by Obstructive Sleep Apnea: Effects of Continuous Positive Airway Pressure (CPAP), Massive Weight Loss and the Bioactive Compound Resveratrol

UPDATED May 2016:

Originally the study design included investigation of the effects of the bioactive compound resveratrol compared to placebo tablets and to CPAP treatment. Due to fewer subjects having OSA than estimated by pre-study and, therefore, difficulties in the recruiting process the investigators have found it necessary to descale the study design. Hence, we have discontinued the resveratrol and CPAP intervention and will focus on the cross-sectional investigation of metabolic changes in subjects with and without OSA and the effect of weight loss after bariatric surgery on inflammation, OSA severity, metabolism and arterial stiffness.

Obstructive sleep apnea (OSA) is a common disorder especially among obese individuals and patients with type 2 diabetes. OSA is associated with an increased morbidity and mortality.

Continuous positive airway pressure (CPAP) is the standard treatment. Also weight loss is known to reduce the severity of OSA, especially bariatric surgery has proven effective because of the massive weight loss.

The investigators hypothesize that OSA via pro-inflammatory responses in various tissues causes low-grade inflammation which ultimately induce the associated co-morbidities. The investigators hypothesize that massive weight loss after bariatric surgery have beneficial effects on severity of OSA, inflammatory status and improves insulin sensitivity.

Study Overview

• Status: Completed
• Conditions: Obesity; Obstructive Sleep Apnea

Detailed Description

UPDATED May 2016:

Originally the study design included investigation of the effects of the bioactive compound resveratrol compared to placebo tablets and to CPAP treatment. Due to fewer subjects having OSA than estimated by pre-study and, therefore, difficulties in the recruiting process the investigators have found it necessary to descale the study design. Hence, we have discontinued the resveratrol and CPAP intervention and will focus on the cross-sectional investigation of metabolic changes in subjects with and without OSA and the effect of weight loss after bariatric surgery on inflammation, OSA severity, metabolism and arterial stiffness.

OSA causes insulin resistance and seems to aggravate obesity related comorbidities such as hypertension, dyslipidemia and increase the risk of development of type 2 diabetes and non-alcoholic fatty liver disease.

More mechanisms may be involved in the pathogenesis of these negative effects from OSA but hypoxia-induced low-grade inflammation may play a central role since the levels of inflammatory markers generally are elevated in OSA. The tissues which are responsible for these systemic alterations are not known, however, adipose tissue might be a good candidate since it is known from studies that human adipose tissue can influence systemic inflammation.

Some studies even describe a small but significant anti-inflammatory effect and a beneficial effect on glucose metabolism following CPAP treatment. In addition, weight loss in patients with OSA is known to reduce the severity of or completely eliminate OSA.

The purpose of this study is primarily to investigate:

1. the metabolic changes in adipose and liver tissue induced by OSA in order to better understand how OSA negatively affects whole-body metabolism
2. the effect of weight loss after bariatric surgery on systemic inflammation, metabolism and the severity of OSA

24 subjects scheduled to undergo bariatric surgery will be recruited. They will all be screened for OSA. 12 subjects without OSA and 12 subjects with OSA will be included and examined before surgery and 6 months post-surgery.

The investigators will look at changes in:

• Inflammation-markers
• Biochemical markers of fat and sugar-metabolism
• Gene-expression in adipose and liver-tissue
• Severity of OSA
• Pulse-wave velocity

• Study Type: Observational
• Enrollment (Actual): 27

Contacts and Locations

Study Locations

• Denmark
  • Aarhus C, Denmark, 8000
    • Aarhus University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 25 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Study groups will be selected from subjects referred to the outpatient clinics in Central Denmark Region and who meet the national guideline criteria for bariatric surgery.

Description

Inclusion Criteria:

• Female/Male
• Legally competent (habil)
• 25-65 years old
• BMI > 35 and fulfill criteria for bariatric surgery in Denmark
• Written informed consent

Exclusion Criteria:

• Current treatment with CPAP
• Permanent treatment with glucocorticoids, NSAID or sleeping pills (otherwise discontinued for 1 week prior to inclusion)
• Severe heart, liver, kidney or lung disease
• Type 1 diabetes
• Work in transportation-related industry
• Pregnancy
• Substance abuse problem

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Obstructive Sleep Apnea; Subjects scheduled to undergo bariatric surgery and with Obstructive Sleep Apnea
No Obstructive Sleep Apnea, controls; Subjects scheduled to undergo bariatric surgery and without Obstructive Sleep Apnea, control group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metabolic changes in adipose and liver tissue induced by OSA. Obese subjects with OSA will be compared to obese subjects without OSA.	Cross-sectional genetic and metabolic analysis of biopsies and blood samples obtained in relation to bariatric surgery on subjects with and without sleep apnea. In tissue samples gene-expression profile is measured using Affymetrix gene array and blood samples are used for metabolic profiling and inflammatory markers (hs-CRP, TNFalfa, IL-6, IL-8, adiponectin, leptin, MCP-1, FGF211, CD163)	Biopsies and blood samples obtained in relation to bariatric surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Effect of bariatric surgery on adipose tissue inflammation and systemic inflammation.	Changes in inflammation markers (hs-CRP, TNFalfa, IL-6, IL-8, adiponectin, leptin, MCP-1, FGF21, CD163) in blood and adipose tissue. Changes in expression of mRNA of the relevant inflammatory pathways assessed by gene expression studies.	Evaluated at time of bariatric surgery and at follow-up 6 months after bariatric surgery.
Effect of bariatric surgery on insulin sensitivity.	Changes in insulin sensitivity assessed by HOMA-IR, fructosamine and correction in oral anti diabetic medication.	Evaluated at time of bariatric surgery and at follow-up 6 months after bariatric surgery
Effect of bariatric surgery on the severity of OSA.	Changes in AHI-score and Sleepiness Score (based on questionnaires).	Evaluated at baseline, 4 weeks post-bariatric surgery and 6 months post-bariatric surgery

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Arterial stiffness assessed by office carotid-femoral pulse-wave	Changes in arterial stiffness assessed by office carotid-femoral pulse-wave velocity	Evaluated at baseline, end of intervention and 6 months post-bariatric surgery

Collaborators and Investigators

• Sponsor: University of Aarhus
• Investigators: Principal Investigator: Steen B Pedersen, MD,Professor, Aarhus University Hospital

Study record dates

Study Major Dates

• Study Start: April 1, 2015
• Primary Completion (Actual): September 1, 2017
• Study Completion (Actual): September 19, 2017

Study Registration Dates

• First Submitted: March 30, 2015
• First Submitted That Met QC Criteria: April 13, 2015
• First Posted (Estimate): April 17, 2015

Study Record Updates

• Last Update Posted (Actual): October 17, 2017
• Last Update Submitted That Met QC Criteria: October 16, 2017
• Last Verified: January 1, 2016

More Information

Terms related to this study

• Keywords: Inflammation; Insulin resistance; Bariatric surgery
• Additional Relevant MeSH Terms: Pathologic Processes; Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Body Weight; Signs and Symptoms, Respiratory; Body Weight Changes; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Inflammation; Apnea; Weight Loss
• Other Study ID Numbers: LIRMOI-5-OSA

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED