In:
Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 130, No. suppl_2 ( 2014-11-25)
Abstract:
Background: OSA is a highly prevalent condition throughout the lifespan, and has emerged as an independent risk factor for atherosclerosis. Macrophages play a key role in the pathogenesis of atherosclerosis through shifts in the continuum between the pro-inflammatory M1 and the athero-protective M2. We hypothesized that Intermittent Hypoxia (IH) during the sleep period, a model for OSA, will induce shifts towards a pro-atherogenic state in the spectrum of macrophages within the aortic vascular wall. Methods: 8-week old male C57BL/6J mice were exposed to IH for 12-hr/day during the light period or to room air (RA) for 6 weeks and were kept on a regular low-fat chow. Following exposure, full-length aortas were dissected and enzymatically digested. Single cell suspensions were prepared and cells were incubated with antibodies for macrophage markers previously implicated in atherogenesis and metabolic dysregulation - CD11b, F4/80, Ly6c, CD36, and CD64, and analyzed by FACS. Results: Macrophages were defined as CD11b+/F4/80+ cells. Significant increases in the percentage of macrophages emerged in IH-exposed mice (6.4%±0.3 vs. 8%±0.3, p=0.003, n=19-20/group). Furthermore, IH induced shifts in the macrophage population toward an M1 pro-inflammatory phenotype. Specifically, IH group showed significantly higher expression of Ly6c, (MFI:522±23 vs. 699±43, p=0.004, n=12/group) and increased the percentage of Ly6c+(hi) cells (9.2% vs. 11.7%, p=0.03). Conversely, tissue-resident marker CD64 expression in the aortic macrophages was down-regulated following IH exposures (MFI:3207±453 vs. 2967±483, p=0.03, n=12/group), while scavenger receptor CD36 expression was increased in the IH-exposed group (MFI:1694±56 vs.2129±209, p=0.005). Conclusion: Intermittent hypoxia during the sleep period leads to early expansion of the macrophage population in the aortic wall in a relatively resistant animal model for development of atherosclerosis, i.e., in the absence of a high-fat diet or of high atherogenic risk predisposing gene knockout. Furthermore IH induces changes in macrophage phenotypes, including a shift towards a pro-inflammatory phenotype, and recruitment of bone-marrow derived macrophages expressing indicators of metabolic activation.
Type of Medium:
Online Resource
ISSN:
0009-7322
,
1524-4539
DOI:
10.1161/circ.130.suppl_2.15724
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2014
detail.hit.zdb_id:
1466401-X
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