title: Anatomic assessment of sympathetic peri-arterial renal nerves in man.
abstract: BACKGROUND
  Although renal sympathetic denervation therapy has shown promising results in patients with resistant hypertension, the human anatomy of peri-arterial renal nerves is poorly understood.
  
  
  OBJECTIVE
  The aim of our study was to investigate the anatomic distribution of peri-arterial sympathetic nerves around human renal arteries.
  
  
  METHODS
  Bilateral renal arteries were collected from human autopsy subjects, and peri-arterial renal nerve anatomy was examined by using morphometric software. The ratio of afferent to efferent nerve fibers was investigated by dual immunofluorescence staining using antibodies targeted for anti-tyrosine hydroxylase and anti-calcitonin gene-related peptide.
  
  
  RESULTS
  A total of 10,329 nerves were identified from 20 (12 hypertensive and 8 nonhypertensive) patients. The mean individual number of nerves in the proximal and middle segments was similar (39.6 ± 16.7 per section and 39.9 ± 1 3.9 per section), whereas the distal segment showed fewer nerves (33.6 ± 13.1 per section) (p = 0.01). Mean subject-specific nerve distance to arterial lumen was greatest in proximal segments (3.40 ± 0.78 mm), followed by middle segments (3.10 ± 0.69 mm), and least in distal segments (2.60 ± 0.77 mm) (p < 0.001). The mean number of nerves in the ventral region (11.0 ± 3.5 per section) was greater compared with the dorsal region (6.2 ± 3.0 per section) (p < 0.001). Efferent nerve fibers were predominant (tyrosine hydroxylase/calcitonin gene-related peptide ratio 25.1 ± 33.4; p < 0.0001). Nerve anatomy in hypertensive patients was not considerably different compared with nonhypertensive patients.
  
  
  CONCLUSIONS
  The density of peri-arterial renal sympathetic nerve fibers is lower in distal segments and dorsal locations. There is a clear predominance of efferent nerve fibers, with decreasing prevalence of afferent nerves from proximal to distal peri-arterial and renal parenchyma. Understanding these anatomic patterns is important for refinement of renal denervation procedures.
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sakakura
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland.
authors.forename: Elena
authors.initials: E
authors.lastname: Ladich
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland.
authors.forename: Qi
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland.
authors.forename: Fumiyuki
authors.initials: F
authors.lastname: Otsuka
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Yahagi
authors.affiliation: Office of the Chief Medical Examiner, Baltimore, Maryland.
authors.forename: David R
authors.initials: DR
authors.lastname: Fowler
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland.
authors.forename: Frank D
authors.initials: FD
authors.lastname: Kolodgie
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland.
authors.forename: Renu
authors.initials: R
authors.lastname: Virmani
authors.affiliation: CVPath Institute, Inc., Gaithersburg, Maryland. Electronic address: mjoner@cvpath.org.
authors.forename: Michael
authors.initials: M
authors.lastname: Joner
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002102:Cadaver; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D007668:Kidney / Q000294:innervation*; D008297:Male; D008875:Middle Aged; D012077:Renal Artery / Q000294:innervation*; D013562:Sympathectomy; D013564:Sympathetic Nervous System / Q000033:anatomy & histology*
keywords: anatomy; pathology; renal denervation; sympathetic nerve