The Role of Oxidative Stress in the Cardiovascular Consequences of Sleep Apnea

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00701441
Recruitment Status : Completed
First Posted : June 19, 2008
Results First Posted : October 30, 2013
Last Update Posted : October 30, 2013
Information provided by (Responsible Party):
Rami Khayat, Ohio State University

Brief Summary:

Obstructive Sleep Apnea (OSA) is the most common sleep disorder affecting up to 9-24 percent of middle aged adults, and is becoming increasingly implicated in the pathogenesis of hypertension, and other cardiovascular disorders. Up to half of patients with OSA have hypertension, and their risk of developing hypertension increases with the increasing severity of Sleep Apnea. Patients with OSA and no hypertension have endothelial dysfunction, which is believed to be the precursor for most cardiovascular disorders.

The upper airway collapse and obstruction that occur in OSA result in a pattern of intermittent hypoxia, that has been shown to be the cause of the hypertension, and endothelial dysfunction found in patients with OSA. Intermittent hypoxia results in oxidative stress, which in turn is linked to the pathogenesis of hypertension and endothelial dysfunction.

This protocol evaluates the role of the oxidative stress in endothelial function and blood pressure in patients with OSA. This is a pilot clinical study that will compare oxidative stress parameters, and endothelial function in patients with OSA before starting treatment with continuous positive airway pressure (CPAP) and 12 weeks post being on CPAP. These patients will be compared to control patients with no history of OSA. the study does not involve assignement to different treatments. All patients will receive the indicated treatment for OSA and measurements will be collected before and 12 weeks after adequate treatment.

Condition or disease
Sleep Apnea

Detailed Description:

Obstructive Sleep Apnea (OSA) is increasingly recognized as a cardiovascular risk factor. OSA is a cause of hypertension and has strong association with atherosclerosis, coronary heart disease, diabetes stroke , and fatal cardiovascular events. Endothelial dysfunction is a preclinical vascular abnormality that predicts subsequent development of vascular disease . Patients with OSA demonstrate endothelial dysfunction in the absence of any manifested vascular disease . The mechanism of endothelial dysfunction in OSA is largely unknown. Endothelial dysfunction in OSA is reversible with antioxidants, suggesting a role for oxidant overproduction in the decreased NO availability in OSA. This provides parallels to other cardiovascular diseases in which oxidative stress induced endothelial dysfunction is important.

Recent studies reported evidence of dysfunction or decreased expression of endothelial nitric oxide synthase (eNOS) in association with increased peroxynitrite in harvested venous endothelial cells of OSA patients. We endeavored to perform the first direct quantification of microvascular endothelial genes from OSA patients. We hypothesized that patients with OSA who are free of any cardiovascular disease will have early functional changes in the microcirculatory endothelial cells that are associated with OSA, and therefore would resolve with treatment. Given the role of oxidative stress in the vascular disease of OSA, we expected to find evidence of superoxide overproduction in the microcirculatory vessels. We expected these functional changes to be reversible with treatment of OSA.

Measurement of superoxide will be done on the subcutaneous biopsy tissue using quantitative Polymerase Chain Reaction (qPCR) and immunohistochemistry techniques and image analysis software. Measurement of endothelial function will be done using Doppler ultrasound.

Study Type : Observational
Actual Enrollment : 25 participants
Observational Model: Case Control
Time Perspective: Prospective
Official Title: The Role of Oxidative Stress in the Cardiovascular Consequences of Sleep Apnea
Study Start Date : February 2007
Actual Primary Completion Date : June 2010
Actual Study Completion Date : June 2010

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Sleep Apnea

Control group: healthy individuals without OSA
healthy individuals without OSA who are matched in weight and age to the participating OSA patients
OSA group
Patients in the OSA group receive CPAP for 12 weeks as part of their care. patients with OSA provide measures at baseline and after 12 weeks of CPAP treatment.

Primary Outcome Measures :
  1. Flow Mediated Dilation [ Time Frame: Baseline and 12 weeks ]
    A non-invasive test using an ultrasound to measure baseline resting vessel diameter and vessel wall dilation in upper arm post application of an inflated blood pressure cuff for five minutes. The percentage change in vessel wall dilation due to stimulation from the resting vessel diameter will be calculated for each group of participants. The results will be compared relative to each group of participants.

Other Outcome Measures:
  1. Peroxynitrite Deposition in the Vascular Walls [ Time Frame: baseline and 12 weeks ]
    A forearm biopsy will be collected to isolate human microcirculatory endothelial cells. The stain density of peroxynitrite, an indicator of oxidative stress, in the vascular walls is compared between pre-treatment and post treatment patient tissue. Also another comparison is made between pre-treatment and control tissue. The stain density is a software-generated measurement of pixel intensity and is considered to be an arbitrary unit. Higher numbers indicate greater density

Biospecimen Retention:   Samples With DNA
Blood and tissue biopsy

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
People screened for sleep apnea with a completed sleep study who do not have hypertension or coronary artery disease.

Inclusion Criteria:

  • Completed sleep study - Older than 18

Exclusion Criteria:

  • Hypertension
  • Diabetes
  • coronary disease
  • Peripheral vascular disease
  • High cholesterol
  • Smoking
  • Pregnancy
  • Use of erectile dysfunction medications or supplements

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00701441

United States, Ohio
The Ohio State University
Columbus, Ohio, United States, 43212
Sponsors and Collaborators
Rami Khayat
Principal Investigator: Rami Khayat, MD Ohio State University

Publications of Results:
Responsible Party: Rami Khayat, Associate Professor, Ohio State University Identifier: NCT00701441     History of Changes
Other Study ID Numbers: 2005H0221
First Posted: June 19, 2008    Key Record Dates
Results First Posted: October 30, 2013
Last Update Posted: October 30, 2013
Last Verified: October 2013

Keywords provided by Rami Khayat, Ohio State University:
sleep apnea,
oxidative stress

Additional relevant MeSH terms:
Sleep Apnea Syndromes
Respiration Disorders
Respiratory Tract Diseases
Signs and Symptoms, Respiratory
Signs and Symptoms
Sleep Disorders, Intrinsic
Sleep Wake Disorders
Nervous System Diseases