title: Androgens and morphologic remodeling at penile and cardiovascular levels: a common piece in complicated puzzles?
abstract: BACKGROUND
  Epidemiologic data demonstrate a protective role by normal androgen levels on cardiovascular health and erectile function. Low androgen levels are associated with erectile dysfunction and increased risk of cardiovascular diseases. Both conditions recognize as anatomic substrate a pathologic structural remodeling. Direct androgen effects on male external genitalia, vascular wall, and myocardium have been reported.
  
  
  OBJECTIVE
  To review current knowledge about androgen-dependent molecular signaling pathways and cellular events within penile and cardiovascular tissues involved in the homeostatic control of morphologic tissue properties and in the development of structural remodeling in presence of normal and low androgen levels, respectively.
  
  
  METHODS
  A literature search was performed in November 2008 using the commercially available Medline online engine search to retrieve studies (from 1998 to 2008) on the mechanisms mediating the role of androgens on penile and cardiovascular morphologic homeostasis and remodeling. A combination of the following medical subject headings was used: androgens, hypogonadism, vessel tissue architecture, remodeling, cardiovascular system, and penis.
  
  
  RESULTS
  Androgens exert direct beneficial effects on both cardiovascular and penile tissues. Endothelial cells and smooth-muscle cells are the main cellular targets for direct androgen effects in both tissues and are involved in pathologic remodeling in hypogonadal models. At vascular level, androgens promote endothelial cell survival, reduce endothelial expression of proinflammatory markers, and inhibit proliferation and intimal migration of vascular smooth-muscle cells. At penile level, low androgen levels are associated with apoptosis of endothelial cells and smooth-muscle cells. Moreover, low androgen levels impair proliferation, migration, and homing of endothelial progenitor cells as well as myogenic differentiation of mesenchymal progenitor cells.
  
  
  CONCLUSIONS
  Normal androgen levels promote vascular and penile homeostasis by direct mechanisms mainly involving endothelial cells and smooth-muscle cells. Low androgen levels are associated with impairments of such mechanisms, leading to pathologic structural remodeling.
authors.affiliation: Department of Urology-University Federico II, Naples, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Mirone
authors.forename: Ciro
authors.initials: C
authors.lastname: Imbimbo
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Fusco
authors.forename: Paolo
authors.initials: P
authors.lastname: Verze
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Creta
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Tajana
mesh_terms: D000728:Androgens / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000209:etiology; D002320:Cardiovascular Physiological Phenomena; D006706:Homeostasis; D006801:Humans; D018783:Impotence, Vasculogenic / Q000209:etiology; D008297:Male; D010413:Penis / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D000728:Androgens