Obstructive sleep apnea (OSA), a condition that affects a quarter of the Western adults, triples the risk for cardiovascular diseases and increases all-cause mortality. Intermittent hypoxia (IH) during transient cessation of breathing in OSA leads to endothelial inflammation, a key step in the initiation and progression of cardiovascular disease. However, the mechanisms that mediate IH-induced endothelial inflammation remain unclear and, consequently, no targeted therapy is available for vascular manifestations of OSA. Using endothelial cells (ECs) freshly harvested from OSA patients, we have identified impaired complement inhibition as an initial stimulus for endothelial inflammation in IH, thereby linking for the first time complement activation to vascular risk in OSA. We found that a major complement inhibitor CD59, a plasma membrane protein that inhibits the formation of the terminal complement membrane attack complex (MAC) and protects host cells from complement injury, is internalized from the EC surface in OSA patients. Consequent MAC deposition initiates endothelial inflammation in IH, as evidenced by nuclear translocation of nuclear factor-kappa B and increased expression of inflammatory cytokines. Importantly, we showed that IH does not significantly affect nuclear factor-kappa B activity and levels of pro-inflammatory cytokines in ECs in the absence of complement, suggesting that complement activation has an essential role in endothelial inflammation in OSA. Interestingly, internalization of CD59 in IH appears to be cholesterol-dependent and statins prevent MAC deposition on ECs in IH in a CD59-dependent manner, suggesting a novel therapeutic strategy to reduce vascular risk in OSA. This led us to hypothesize that IH-induced cellular cholesterol accumulation reduces complement inhibition via increased internalization of CD59 from the EC surface leading to increased MAC deposition, endothelial inflammation and dysfunction in OSA and that treatment of OSA with CPAP and/or statins reverses endothelial dysfunction by restoring complement inhibition. To accomplish this goal we propose the following 3 Specific Aims: 1) To determine whether reduced complement inhibition promotes endothelial dysfunction in OSA and whether CPAP reverses these changes, 2) To determine whether reduced complement inhibition is mediated by cholesterol accumulation in ECs in OSA and whether CPAP reverses these changes, and 3) To determine whether statins prevent endothelial dysfunction in OSA by preserving complement inhibition using randomized design. Using an innovative approach to characterize human vascular endothelium, the proposed studies may advance our understanding of vascular dysfunction in OSA and provide the basis for clinical trials of novel therapeutic strategies, such as addition of statins to the standard CPAP therapy, for preventing and/or reversing vascular risk in OSA.

Public Health Relevance

-Jelic Obstructive sleep apnea (OSA), a condition that affects a quarter of American adults, triples the risk for cardiovascular diseases and increases all-cause mortality. Using an innovative approach to directly characterize endothelial cells in OSA patients, we have identified novel molecular mechanism that initiates endothelial inflammation in OSA patients, and observed that the abnormal cycle of endothelial inflammation can be disrupted with statin therapy. We now propose to determine whether restoring endothelial protection with statins can reverse endothelial dysfunction in OSA patients. These studies may provide the basis for larger and longer clinical trials of novel therapeutic strategies, such as addition of statins to the standard CPAP therapy, for preventing and/or reversing cardiovascular risk in OSA.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL106041-07
Application #
9533893
Study Section
Cancer, Heart, and Sleep Epidemiology B Study Section (CHSB)
Program Officer
Laposky, Aaron D
Project Start
2011-06-01
Project End
2020-05-31
Budget Start
2018-06-01
Budget End
2019-05-31
Support Year
7
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
621889815
City
New York
State
NY
Country
United States
Zip Code
10032
Manichaikul, Ani; Sun, Li; Borczuk, Alain C et al. (2017) Plasma Soluble Receptor for Advanced Glycation End Products in Idiopathic Pulmonary Fibrosis. Ann Am Thorac Soc 14:628-635
Emin, Memet; Wang, Gang; Castagna, Francesco et al. (2016) Increased internalization of complement inhibitor CD59 may contribute to endothelial inflammation in obstructive sleep apnea. Sci Transl Med 8:320ra1
Castagna, F; Wang, J; Emit, M et al. (2015) 9A.09: PROTECTION AGAINST COMPLEMENT ACTIVITY IS REDUCED IN ARTERIAL HYPERTENSION. J Hypertens 33 Suppl 1:e119
Adams, Tessa; Wan, Elaine; Wei, Ying et al. (2015) Secondhand Smoking Is Associated With Vascular Inflammation. Chest 148:112-119
Padeletti, Margherita; Zacà, Valerio; Mondillo, Sergio et al. (2014) Sleep-disordered breathing increases the risk of arrhythmias. J Cardiovasc Med (Hagerstown) 15:411-6
Patel, Nina M; Kawut, Steven M; Jelic, Sanja et al. (2013) Pulmonary arteriole gene expression signature in idiopathic pulmonary fibrosis. Eur Respir J 41:1324-30
Padeletti, Margherita; Caputo, Maria; Zacà, Valerio et al. (2013) Effect of bosentan on pulmonary hypertension secondary to systolic heart failure. Pharmacology 92:281-5
Marin, José M; Agusti, Alvar; Villar, Isabel et al. (2012) Association between treated and untreated obstructive sleep apnea and risk of hypertension. JAMA 307:2169-76
Lederer, David J; Jelic, Sanja; Bhattacharya, Jahar et al. (2012) Is obstructive sleep apnea a cause of idiopathic pulmonary fibrosis? Arch Pathol Lab Med 136:470; author reply 470
Krieger, Ana C; Green, Daniel; Cruz, Muriel T et al. (2011) Predictors of oxidative stress in heart failure patients with Cheyne-Stokes respiration. Sleep Breath 15:827-35

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