title: The complex structure of the smooth muscle layer of spermatic veins and its potential role in the development of varicocele testis.
abstract: OBJECTIVE
  Varicocele, a dilatation of the pampiniform venous plexus, is considered to cause male infertility. The exact mechanism of varicocele development is not clarified yet. This study focused on the structure of varicocele veins, compared with normal spermatic veins, and its potential role in varicocele development.
  
  
  METHODS
  Morphologic and immunohistochemical studies using antibodies against vWF and neurofilament-200 (NF-200) were performed on spermatic vein fragments of 20 varicocele patients and 40 normal spermatic cords. Casting preparation of veins was performed on five normal spermatic cords.
  
  
  RESULTS
  Casting preparation frequently revealed circular constrictions of normal spermatic vein lumina. Histologic evaluation showed a strong longitudinal smooth muscle layer in the adventitia of large veins in addition to the circularly organised tunica media. Serial sections showed smooth muscle fibres branching from the outer longitudinal into the inner circular layer. Immunostaining for vWF revealed high vascularisation of this outer layer. Interestingly, the number of nerve fibres marked by NF-200 immunostaining was considerably higher in large veins compared to the testicular artery. The longitudinal smooth muscle layer was significantly degraded in the presence of varicocele grades I and II, and did not even exist in varicocele grade III. Correspondingly, the number of vasa vasorum and nerve fibres was reduced in varicocele veins.
  
  
  CONCLUSIONS
  Our data show a complex smooth muscle organisation of spermatic veins, which serves the basis for a contractile mechanism, providing an effective blood transport through pampiniform plexus. This mechanism is obviously damaged in the varicocele. Molecular processes behind this impairment remain to be clarified.
authors.affiliation: Department of Urology, University Hospital Grosshadern-Munich, Marchioninistrasse 15, D-81377 Munich, Germany. Derya.Tilki@med.uni-muenchen.de
authors.forename: Derya
authors.initials: D
authors.lastname: Tilki
authors.forename: Ergin
authors.initials: E
authors.lastname: Kilic
authors.forename: Robert
authors.initials: R
authors.lastname: Tauber
authors.forename: Dietrich
authors.initials: D
authors.lastname: Pfeiffer
authors.forename: Christian G
authors.initials: CG
authors.lastname: Stief
authors.forename: Roland
authors.initials: R
authors.lastname: Tauber
authors.forename: Süleyman
authors.initials: S
authors.lastname: Ergün
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000473:pathology*; D016900:Neurofilament Proteins / Q000032:analysis; D013085:Spermatic Cord; D013737:Testis / Q000098:blood supply*; D014646:Varicocele / Q000473:pathology*; D014680:Veins / Q000737:chemistry / Q000294:innervation / Q000473:pathology*; D014841:von Willebrand Factor / Q000032:analysis
chemical_list: D016900:Neurofilament Proteins; D014841:von Willebrand Factor; C051774:neurofilament protein H