Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32610.
Hypertension. 2014 Mar;63(3):542-50. doi: 10.1161/HYPERTENSIONAHA.113.02722. Epub 2013 Dec 23.
Autonomic nervous system dysfunction, exaggerated inflammation, and impaired vascular repair are all hallmarks of hypertension. Considering that bone marrow (BM) is a major source of the inflammatory cells (ICs) and endothelial progenitor cells (EPCs), we hypothesized that impaired BM-autonomic nervous system interaction contributes to dysfunctional BM activity in hypertension. In the spontaneously hypertensive rat (SHR), we observed a >30% increase in BM and blood ICs (CD4.8(+)) and a >50% decrease in EPCs (CD90(+).CD4.5.8(-)) when compared with the normotensive Wistar-Kyoto rat. Increased tyrosine hydroxylase (70%) and norepinephrine (160%) and decreased choline acetyl transferase (30%) and acetylcholine esterase (55%) indicated imbalanced autonomic nervous system in SHR BM. In Wistar-Kyoto rat, night time-associated elevation in sympathetic nerve activity (50%) and BM norepinephrine (41%) was associated with increased ICs (50%) and decreased EPCs (350%) although BM sympathetic denervation decreased ICs (25%) and increased EPCs (40%). In contrast, these effects were blunted in SHR, possibly because of chronic downregulation of BM adrenergic receptor α2a (by 50%-80%) and β2 (30%-45%). Application of norepinephrine resulted in increased BM IC activation/release, which was prevented by preadministration of acetylcholine. Electrophysiological recordings of femoral sympathetic nerve activity showed a more robust femoral sympathetic nerve activity in SHR when compared with Wistar-Kyoto rat, peaking earlier in the respiratory cycle, indicative of increased sympathetic tone. Finally, manganese-enhanced MRI demonstrated that presympathetic neuronal activation in SHR was associated with an accelerated retrograde transport of the green fluorescent protein-labeled pseudorabies virus from the BM. These observations demonstrate that a dysfunctional BM autonomic nervous system is associated with imbalanced EPCs and ICs in hypertension.
自主神经系统功能障碍、炎症反应过度和血管修复受损都是高血压的特征。考虑到骨髓(BM)是炎症细胞(ICs)和内皮祖细胞(EPCs)的主要来源,我们假设受损的 BM-自主神经系统相互作用导致高血压中 BM 功能障碍。在自发性高血压大鼠(SHR)中,与正常血压的 Wistar-Kyoto 大鼠相比,BM 和血液中的 IC(CD4.8(+))增加了>30%,EPC(CD90(+)。CD4.5.8(-))减少了>50%。SHR BM 中的酪氨酸羟化酶(70%)和去甲肾上腺素(160%)增加,胆碱乙酰转移酶(30%)和乙酰胆碱酯酶(55%)减少,表明自主神经系统失衡。在 Wistar-Kyoto 大鼠中,夜间交感神经活性(50%)和 BM 去甲肾上腺素(41%)的升高与 IC(50%)的增加和 EPC(350%)的减少有关,尽管 BM 交感神经去神经支配减少了 IC(25%)并增加了 EPC(40%)。相比之下,这些影响在 SHR 中被削弱,可能是由于 BM 肾上腺素能受体α2a(减少 50%-80%)和β2(减少 30%-45%)的慢性下调。去甲肾上腺素的应用导致 BM IC 激活/释放增加,而乙酰胆碱的预先给予可防止这种增加。股交感神经活动的电生理记录显示,SHR 的股交感神经活动比 Wistar-Kyoto 大鼠更强,在呼吸周期早期达到峰值,表明交感神经张力增加。最后,锰增强 MRI 显示,SHR 中的节前神经元激活与从 BM 逆行运输的绿色荧光蛋白标记的伪狂犬病病毒加速有关。这些观察结果表明,功能障碍的 BM 自主神经系统与高血压中 EPC 和 IC 的失衡有关。