Rajesh Kumar1, Tiffany T Pham2, Paul M Macey3, Mary A Woo4, Frisca L Yan-Go5, Ronald M Harper6. 1. Department of Anesthesiology ; Department of Radiological Sciences ; The Brain Research Institute, University of California at Los Angeles, Los Angeles, CA. 2. Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA. 3. UCLA School of Nursing, Los Angeles, CA ; The Brain Research Institute, University of California at Los Angeles, Los Angeles, CA. 4. UCLA School of Nursing, Los Angeles, CA. 5. Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA. 6. Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA ; The Brain Research Institute, University of California at Los Angeles, Los Angeles, CA.
Abstract
STUDY OBJECTIVES: Patients with obstructive sleep apnea (OSA) show significant white matter injury; whether that injury represents myelin or axonal damage is unclear. The objective was to examine myelin and axonal changes in patients with newly diagnosed OSA over control subjects. DESIGN: Cross-sectional study. SETTING: University-based medical center. PARTICIPANTS: Twenty-three newly-diagnosed, treatment-naïve OSA and 23 age- and sex-matched control subjects. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Radial and axial diffusivity maps, calculated from diffusion tensor imaging data (3.0 Tesla MRI scanner), indicating diffusion perpendicular (myelin status) or parallel (axonal status) to fibers, respectively, were normalized, smoothed, and compared between groups (analysis of covariance; covariate: age). Global brain radial and axial diffusivity values, and global brain volume with myelin and axonal changes were determined, and region-of-interest analyses performed in areas of significant differences between groups based on voxel-based procedures. Global radial and axial diffusivity values were significantly reduced in OSA versus control subjects (radial, P = 0.004; axial, P = 0.019), with radial (myelin) diffusivity reduced more than axial (axonal), and more left-sided reduction for both measures. Localized declines for myelin and axonal measures appeared in the dorsal and ventral medulla, cerebellar cortex and deep nuclei, basal ganglia, hippocampus, amygdala, corpus callosum, insula, cingulate and medial frontal cortices, and other cortical areas (P < 0.005), all regions mediating functions affected in OSA. CONCLUSIONS: Fiber injury appears in critical medullary respiratory regulatory sites, as well as cognitive and autonomic control areas. Myelin is more affected in newly diagnosed OSA than axons, and primarily on the left side, possibly from the increased myelin sensitivity to hypoxia and asymmetric perfusion.
STUDY OBJECTIVES:Patients with obstructive sleep apnea (OSA) show significant white matter injury; whether that injury represents myelin or axonal damage is unclear. The objective was to examine myelin and axonal changes in patients with newly diagnosed OSA over control subjects. DESIGN: Cross-sectional study. SETTING: University-based medical center. PARTICIPANTS: Twenty-three newly-diagnosed, treatment-naïve OSA and 23 age- and sex-matched control subjects. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Radial and axial diffusivity maps, calculated from diffusion tensor imaging data (3.0 Tesla MRI scanner), indicating diffusion perpendicular (myelin status) or parallel (axonal status) to fibers, respectively, were normalized, smoothed, and compared between groups (analysis of covariance; covariate: age). Global brain radial and axial diffusivity values, and global brain volume with myelin and axonal changes were determined, and region-of-interest analyses performed in areas of significant differences between groups based on voxel-based procedures. Global radial and axial diffusivity values were significantly reduced in OSA versus control subjects (radial, P = 0.004; axial, P = 0.019), with radial (myelin) diffusivity reduced more than axial (axonal), and more left-sided reduction for both measures. Localized declines for myelin and axonal measures appeared in the dorsal and ventral medulla, cerebellar cortex and deep nuclei, basal ganglia, hippocampus, amygdala, corpus callosum, insula, cingulate and medial frontal cortices, and other cortical areas (P < 0.005), all regions mediating functions affected in OSA. CONCLUSIONS: Fiber injury appears in critical medullary respiratory regulatory sites, as well as cognitive and autonomic control areas. Myelin is more affected in newly diagnosed OSA than axons, and primarily on the left side, possibly from the increased myelin sensitivity to hypoxia and asymmetric perfusion.
Authors: Mary A Woo; Paul M Macey; Peter T Keens; Rajesh Kumar; Gregg C Fonarow; Michele A Hamilton; Ronald M Harper Journal: Congest Heart Fail Date: 2007 Jan-Feb
Authors: K Minkner; K O Lovblad; H Yilmaz; A Alimenti; L Sekoranja; J Delavelle; R Sztajzel; D A Rüfenacht Journal: Neuroradiology Date: 2005-05-14 Impact factor: 2.804
Authors: Yusuf A Bhagat; Muhammad S Hussain; Robert W Stobbe; Kenneth S Butcher; Derek J Emery; Ashfaq Shuaib; Muzaffar M Siddiqui; Perkash Maheshwari; Fawaz Al-Hussain; Christian Beaulieu Journal: Magn Reson Imaging Date: 2008-04-28 Impact factor: 2.546
Authors: Rebecca L Cross; Rajesh Kumar; Paul M Macey; Lynn V Doering; Jeffry R Alger; Frisca L Yan-Go; Ronald M Harper Journal: Sleep Date: 2008-08 Impact factor: 5.849
Authors: Paul M Macey; Rajesh Kumar; Mary A Woo; Edwin M Valladares; Frisca L Yan-Go; Ronald M Harper Journal: Sleep Date: 2008-07 Impact factor: 5.849
Authors: S Anand Trip; Claudia Wheeler-Kingshott; Stephen J Jones; Wai-Yung Li; Gareth J Barker; Alan J Thompson; Gordon T Plant; David H Miller Journal: Neuroimage Date: 2005-10-20 Impact factor: 6.556
Authors: Rajesh Kumar; Bramley V X Birrer; Paul M Macey; Mary A Woo; Rakesh K Gupta; Frisca L Yan-Go; Ronald M Harper Journal: Neurosci Lett Date: 2008-04-25 Impact factor: 3.046
Authors: Nancy A Pike; Bhaswati Roy; Ritika Gupta; Sadhana Singh; Mary A Woo; Nancy J Halnon; Alan B Lewis; Rajesh Kumar Journal: J Neurosci Res Date: 2018-01-06 Impact factor: 4.164
Authors: Leila Kheirandish-Gozal; Ashish K Sahib; Paul M Macey; Mona F Philby; David Gozal; Rajesh Kumar Journal: Neurosci Lett Date: 2018-06-05 Impact factor: 3.046
Authors: Nadia Gosselin; Andrée-Ann Baril; Ricardo S Osorio; Marta Kaminska; Julie Carrier Journal: Am J Respir Crit Care Med Date: 2019-01-15 Impact factor: 21.405
Authors: Ying Xiong; Xiaohong Joe Zhou; Robyn A Nisi; Kelly R Martin; M Muge Karaman; Kejia Cai; Terri E Weaver Journal: J Magn Reson Imaging Date: 2016-09-14 Impact factor: 4.813