title: Cavernosal expandability is an erectile tissue mechanical property which predicts trabecular histology in an animal model of vasculogenic erectile dysfunction.
abstract: OBJECTIVE
  Reliable, clinically available, non-invasive measurements able to predict trabecular histology without the need for erectile tissue biopsy would improve impotence management, since the percentage of trabecular smooth muscle content has been shown to be associated with corporal veno-occlusive dysfunction. The purpose was to identify whether the erectile tissue mechanical property, cavernosal expandability, correlated with the percentage of trabecular smooth muscle content in an animal model of hypercholesterolemia and ischemic-induced corporal fibrosis.
  
  
  METHODS
  New Zealand White rabbits (6 to 7 months old, 3 to 3.5 kg.), were divided into control (n = 7), hypercholesterolemic (n = 5, 0.5% cholesterol diet) and atherosclerotic groups (n = 8, 0.5% cholesterol diet with balloon de-endothelialization). At 16 weeks, the corpora cavernosa were removed en bloc and submerged in physiologic salt solution, and volume-pressure data were plotted at 20 mm. Hg pressure intervals under trabecular smooth muscle relaxation. Cavernosal expandability, X, (the measure of the ability to achieve high corporal expansion at relatively low intracavernosal pressure) and tunical distensibility, V(E)/V(F), (relative volume of fully erect to flaccid penis) were calculated. Erectile tissue was assessed by computer-assisted color histomorphometry with Masson's trichrome stained sections (30 to 45 high power fields/animal) to assess percentage of trabecular smooth muscle content.
  
  
  RESULTS
  The overall mean percentage of trabecular smooth muscle content and mean cavernosal expandability values were 45.4 +/- 1.6, 39.2 +/- 0.9, 33.9 +/- 0.6 and 0.0165 +/- 3.04 x 10(-3), 0.0116 +/- 1.63 x 10(-3), 0.0118 +/- 1.26 x 10(-3) mm. Hg(-1) for the control, hypercholesterolemic and atherosclerotic groups, respectively (r = 0.87). Significant differences in trabecular smooth muscle content were observed among all 3 groups, and in cavernosal expandability, between control and atherosclerotic groups, as well as between control and hypercholesterolemic groups but not between atherosclerotic and hypercholesterolemic groups.
  
  
  CONCLUSIONS
  The erectile tissue mechanical property, cavernosal expandability, correlated with erectile tissue structural quality. Since cavernosal histology has been shown to predict corporal veno-occlusive function, it is hypothesized that the measurement of cavernosal expandability may become a valuable functional clinical parameter in the diagnosis and treatment of men with erectile dysfunction.
authors.affiliation: Department of Urology, Boston University School of Medicine, Massachusetts 02118, USA.
authors.forename: A
authors.initials: A
authors.lastname: Nehra
authors.forename: K M
authors.initials: KM
authors.lastname: Azadzoi
authors.forename: R B
authors.initials: RB
authors.lastname: Moreland
authors.forename: A
authors.initials: A
authors.lastname: Pabby
authors.forename: M B
authors.initials: MB
authors.lastname: Siroky
authors.forename: R J
authors.initials: RJ
authors.lastname: Krane
authors.forename: I
authors.initials: I
authors.lastname: Goldstein
authors.forename: D
authors.initials: D
authors.lastname: Udelson
mesh_terms: D000818:Animals; D001161:Arteriosclerosis / Q000503:physiopathology; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D006937:Hypercholesterolemia / Q000503:physiopathology; D007091:Image Processing, Computer-Assisted; D018783:Impotence, Vasculogenic / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D010410:Penile Erection / Q000502:physiology*; D011446:Prospective Studies; D011817:Rabbits