Changes in extracellular matrix in subcutaneous small resistance arteries of patients with primary aldosteronism.
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.
Rizzoni
Damiano
D
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.
Paiardi
Silvia
S
Rodella
Luigi
L
Porteri
Enzo
E
De Ciuceis
Carolina
C
Rezzani
Rita
R
Boari
Gianluca E M
GE
Zani
Francesca
F
Miclini
Marco
M
Tiberio
Guido A M
GA
Giulini
Stefano M
SM
Rosei
Claudia Agabiti
CA
Bianchi
Rossella
R
Rosei
Enrico Agabiti
EA
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
D024061:Collagen Type III; D003094:Collagen