Hypoxia Inducible factor1-Alpha Genetic Polymorphism of Obstructive Sleep Apnea
Recruitment status was: Recruiting
|First Submitted Date||July 8, 2007|
|First Posted Date||July 10, 2007|
|Last Update Posted Date||January 14, 2009|
|Start Date||March 2006|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures||Not Provided|
|Original Primary Outcome Measures||Not Provided|
|Change History||Complete list of historical versions of study NCT00498693 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures||Not Provided|
|Original Secondary Outcome Measures||Not Provided|
|Current Other Outcome Measures||Not Provided|
|Original Other Outcome Measures||Not Provided|
|Brief Title||Hypoxia Inducible factor1-Alpha Genetic Polymorphism of Obstructive Sleep Apnea|
|Official Title||Not Provided|
Obstructive sleep apnea syndrome(OSAS) is characterized with recurrent collapse of upper airway during sleep and results in hypoxia and sleep fragmentation. The repeated episodes of hypoxia and sympathetic hyperactivity result in cardiovascular complications, including atherosclerosis, hypertension, coronary artery disease and heart failure. Our data showed among 309 consecutively-admitted OSA patients, 54% patients had cardiovascular diseases.
The hypoxia in OSA is characterized as chronic and intermittent, which leads to sophisticated adaptive mechanisms, like activations of transcriptional factors and critical signaling pathways. HIF-1 is a central component of transcriptional factors involved in hypoxia-induced transcription of specific genes. There are two subunits of HIF-1 transcription factor, which interact with the consensus hypoxia response element in the target genes. The HIF-1 alpha activity is regulated by proline hydroxylation modification and ubiquitination, which is oxygen-tension dependent. HIF-1 alpha target genes encode proteins that increase oxygen delivery, such as vascular endothelial growth factor(VEGF). Our oligo-microarray study showed both HIF and VEGF expression in OSA patients was 1.3 times of control group, which decreased to 46% and 57% respectively after one-month CPAP treatment.
HIF-1 alpha polymorphism could result in increased HIF-1 alpha activity and microvessel density. In clinical observation, HIF-1 polymorphism has been reported to be associated with high altitude adaptation, formation of coronary collaterals in CAD and phenotype of cancer. These findings were possibly explained with effect of HIF on modulation of VEGF.
Several genetic polymorphisms were reported to be associated with OSA, which included TNF alpha, angiotensin converting enzyme and haptoglobin. Only hepatoglobin phenotype is proved to be a risk factor for cardiovascular disease in OSA. In most studies, the patient number is less than suggested.
Therefore, in this study, we hypothesized that HIF-1 gene polymorphism was associated with cardiovascular disease in OSA. And by using large-scale of study population(1000 OSA patients), we examined all regions of the HIF-1 alpha to detect single-nucleotide polymorphisms(SNPs), evaluated the pattern of linkage disequilibrium to compose haplotypes in the gene, and performed association studies in OSA patients with and without cardiovascular disease to achieve the following 3 objectives:(1)To identify specific SNPs of HIF-1 alpha gene related to cardiovascular disease in OSA patients (CVD-OSA).(2)To assay the functional activity of high risk SNPs of HIF-1 alpha on the transcription of VEGF gene.(3)To confirm that the serum level of VEGF in CVD-OSA patients with high risk SNPs of HIF-1 are higher than CVD-OSA patients without. The findings are expected to stratify the risk of OSA patients to specific outcome, or response to specific therapy.
|Study Design||Observational Model: Case Control
Time Perspective: Prospective
|Target Follow-Up Duration||Not Provided|
|Sampling Method||Probability Sample|
|Study Population||patients referred sleep center to rule out obstructive sleep apnea|
|Condition||Sleep Apnea, Obstructive|
|Study Groups/Cohorts||Not Provided|
|Publications *||Pandit JJ. Structure-function relationships: a breath of fresh air--or just more hot air--in sleep apnoea research? Respiration. 2008;76(1):16-8. doi: 10.1159/000127578. Epub 2008 May 8.|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status||Unknown status|
|Completion Date||Not Provided|
|Primary Completion Date||Not Provided|
|Ages||18 Years and older (Adult, Senior)|
|Accepts Healthy Volunteers||No|
|Contacts||Contact information is only displayed when the study is recruiting subjects|
|Listed Location Countries||Taiwan|
|Removed Location Countries|
|Other Study ID Numbers||9561701013|
|Has Data Monitoring Committee||Yes|
|U.S. FDA-regulated Product||Not Provided|
|IPD Sharing Statement||Not Provided|
|Responsible Party||Peilin Lee, National Taiwan University Hospital|
|Study Sponsor||National Taiwan University Hospital|
|PRS Account||National Taiwan University Hospital|
|Verification Date||January 2009|