title: Changes in extracellular matrix in subcutaneous small resistance arteries of patients with primary aldosteronism.
abstract: OBJECTIVE
  It has been previously demonstrated that aldosterone may possess a strong profibrotic action in vitro and in animal models of genetic or experimental hypertension. Our aim was to evaluate whether such a profibrotic action is present also in the human microcirculation.
  
  
  METHODS
  We investigated 13 patients with primary aldosteronism, seven patients with essential hypertension, and 10 normotensive controls. All subjects were submitted to a biopsy of gluteal sc fat tissue. Small resistance arteries were dissected and mounted on an isometric myograph, and the tunica media to internal lumen ratio was measured.
  
  
  METHODS
  The total collagen content within the tunica media was detected (Sirius red staining and image analysis), and collagen subtypes were evaluated using polarized light microscopy; under this condition thicker type I collagen fibers appear orange or red, whereas thinner type III collagen fibers are yellow or green.
  
  
  RESULTS
  Tunica media to internal lumen ratio was significantly increased in primary aldosteronism and in essential hypertension compared with normotensive controls. Clinic blood pressure values were similar in primary aldosteronism and in essential hypertension, and greater than in normotensive controls. Normotensive controls had less total and type III collagen (3.23 +/- 0.58 and 1.60 +/- 0.22%, respectively) in respect to the two hypertensive groups (P < 0.001). Total collagen and type III vascular collagen were significantly greater in primary aldosteronism (total collagen, 8.17 +/- 1.38%; type III collagen, 6.06 +/- 0.74%; P < 0.05) than in essential hypertension (total collagen, 6.84 +/- 1.15%; type III collagen, 5.25 +/- 0.80%).
  
  
  CONCLUSIONS
  Our results indicate that, in small resistance arteries of patients with primary aldosteronism, a pronounced fibrosis may be detected, even more evident than in blood-pressure-matched patients with essential hypertension.
authors.affiliation: Chair of Internal Medicine, Department of Medical and Surgical Sciences, University of Brescia, c/o 2 Medicina Spedali Civili di Brescia, Piazza Spedali Civili 1, 25100 Brescia, Italy. rizzoni@med.unibs.it.
authors.forename: Damiano
authors.initials: D
authors.lastname: Rizzoni
authors.forename: Silvia
authors.initials: S
authors.lastname: Paiardi
authors.forename: Luigi
authors.initials: L
authors.lastname: Rodella
authors.forename: Enzo
authors.initials: E
authors.lastname: Porteri
authors.forename: Carolina
authors.initials: C
authors.lastname: De Ciuceis
authors.forename: Rita
authors.initials: R
authors.lastname: Rezzani
authors.forename: Gianluca E M
authors.initials: GE
authors.lastname: Boari
authors.forename: Francesca
authors.initials: F
authors.lastname: Zani
authors.forename: Marco
authors.initials: M
authors.lastname: Miclini
authors.forename: Guido A M
authors.initials: GA
authors.lastname: Tiberio
authors.forename: Stefano M
authors.initials: SM
authors.lastname: Giulini
authors.forename: Claudia Agabiti
authors.initials: CA
authors.lastname: Rosei
authors.forename: Rossella
authors.initials: R
authors.lastname: Bianchi
authors.forename: Enrico Agabiti
authors.initials: EA
authors.lastname: Rosei
mesh_terms: D000273:Adipose Tissue / Q000098:blood supply; D000328:Adult; D001158:Arteries / Q000648:ultrastructure*; D003094:Collagen / Q000032:analysis; D024061:Collagen Type III / Q000032:analysis; D005109:Extracellular Matrix / Q000737:chemistry / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000378:metabolism / Q000473:pathology*; D006973:Hypertension / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D017540:Tunica Media / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D024061:Collagen Type III; D003094:Collagen