Altered inflammatory response is associated with an impaired autonomic input to the bone marrow in the spontaneously hypertensive rat Academic Article uri icon

Overview

MeSH Major

  • Autonomic Nervous System
  • Blood Pressure
  • Bone Marrow
  • Hypertension

abstract

  • 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.

publication date

  • March 2014

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed Central ID

  • PMC3945212

Digital Object Identifier (DOI)

  • 10.1161/HYPERTENSIONAHA.113.02722

PubMed ID

  • 24366083

Additional Document Info

start page

  • 542

end page

  • 50

volume

  • 63

number

  • 3