title: The morphological substrate for Renal Denervation: Nerve distribution patterns and parasympathetic nerves. A post-mortem histological study.
abstract: BACKGROUND
  Renal Denervation as a possible treatment for hypertension has been studied extensively, but knowledge on the distribution of nerves surrounding the renal artery is still incomplete. While sympathetic and sensory nerves have been demonstrated, there is no mention of the presence of parasympathetic nerve fibers.
  
  
  OBJECTIVE
  To provide a description of the distribution patterns of the renal nerves in man, and, in addition, provide a detailed representation of the relative contribution of the sympathetic, parasympathetic and afferent divisions of the autonomic nervous system.
  
  
  METHODS
  Renal arteries of human cadavers were each divided into four longitudinal segments and immunohistochemically stained with specific markers for afferent, parasympathetic and sympathetic nerves. Nerve fibers were semi-automatically quantified by computerized image analysis, and expressed as cross-sectional area relative to the distance to the lumen.
  
  
  RESULTS
  A total of 3372 nerve segments were identified in 8 arteries of 7 cadavers. Sympathetic, parasympathetic and afferent nerves contributed for 73.5% (95% CI: 65.4-81.5%), 17.9% (10.7-25.1%) and 8.7% (5.0-12.3%) of the total cross-sectional nerve area, respectively. Nerves are closer to the lumen in more distal segments and larger bundles that presumably innervate the kidney lie at 1-3.5mm distance from the lumen. The tissue-penetration depth of the ablation required to destroy 50% of the nerve fibers is 2.37 mm in the proximal segment and 1.78 mm in the most distal segments.
  
  
  CONCLUSIONS
  Sympathetic, parasympathetic and afferent nerves exist in the vicinity of the renal artery. The results warrant further investigation of the role of the parasympathetic nervous system on renal physiology, and may contribute to refinement of the procedure by focusing the ablation on the most distal segment.
authors.affiliation: Department of Anatomy, University Medical Center Utrecht, Utrecht, Netherlands. Electronic address: w.a.c.vanamsterdam@gmail.com.
authors.forename: Wouter A C
authors.initials: WA
authors.lastname: van Amsterdam
authors.affiliation: Department of Nephrology, University Medical Center Utrecht, Utrecht, Netherlands.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Blankestijn
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Goldschmeding
authors.affiliation: Department of Anatomy, University Medical Center Utrecht, Utrecht, Netherlands. Electronic address: r.l.a.w.bleys@umcutrecht.nl.
authors.forename: Ronald L A W
authors.initials: RL
authors.lastname: Bleys
mesh_terms: D000293:Adolescent; D000344:Afferent Pathways / Q000033:anatomy & histology; D000368:Aged; D019412:Anatomy, Cross-Sectional; D001341:Autonomic Nervous System / Q000033:anatomy & histology / Q000601:surgery; D002102:Cadaver; D003714:Denervation / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007668:Kidney / Q000033:anatomy & histology / Q000294:innervation*; D008297:Male; D008875:Middle Aged; D017764:Parasympathectomy / Q000379:methods*; D010275:Parasympathetic Nervous System / Q000033:anatomy & histology*; D012077:Renal Artery / Q000033:anatomy & histology / Q000294:innervation
keywords: Anatomy; Autonomic nervous system; Hypertension; Renal Denervation; Renal physiology