Elastin haploinsufficiency induces alternative aging processes in the aorta.
Elastin, the main component of elastic fibers, is synthesized only in early life and provides the blood vessels with their elastic properties. With aging, elastin is progressively degraded, leading to arterial enlargement, stiffening, and dysfunction. Also, elastin is a key regulator of vascular smooth muscle cell proliferation and migration during development since heterozygous mutations in its gene (Eln) are responsible for a severe obstructive vascular disease, supravalvular aortic stenosis, isolated or associated to Williams syndrome. Here, we have studied whether early elastin synthesis could also influence the aging processes, by comparing the structure and function of ascending aorta from 6- and 24-month-old Eln+/- and Eln+/+ mice. Eln+/- animals have high blood pressure and arteries with smaller diameters and more rigid walls containing additional although thinner elastic lamellas. Nevertheless, longevity of these animals is unaffected. In young adult Eln+/- mice, some features resemble vascular aging of wild-type animals: cardiac hypertrophy, loss of elasticity of the arterial wall through enhanced fragmentation of the elastic fibers, and extracellular matrix accumulation in the aortic wall, in particular in the intima. In Eln+/- animals, we also observed an age-dependent alteration of endothelial vasorelaxant function. On the contrary, Eln+/- mice were protected from several classical consequences of aging visible in aged Eln+/+ mice, such as arterial wall thickening and alteration of alpha(1)-adrenoceptor-mediated vasoconstriction. Our results suggest that early elastin expression and organization modify arterial aging through their impact on both vascular cell physiology and structure and mechanics of blood vessels.
Pezet
Mylène
M
Université Joseph Fourier, UFR de Biologie, Grenoble, France.
Jacob
Marie-Paule
MP
Escoubet
Brigitte
B
Gheduzzi
Dealba
D
Tillet
Emmanuelle
E
Perret
Pascale
P
Huber
Philippe
P
Quaglino
Daniela
D
Vranckx
Roger
R
Li
Dean Y
DY
Starcher
Barry
B
Boyle
Walter A
WA
Mecham
Robert P
RP
Faury
Gilles
G
D000375:Aging / Q000235:genetics* / Q000502:physiology; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D002320:Cardiovascular Physiological Phenomena; D003895:Desmosine / Q000032:analysis; D004549:Elastin / Q000737:chemistry / Q000235:genetics*; D016326:Extracellular Matrix Proteins / Q000235:genetics; D005786:Gene Expression Regulation; D006909:Hydroxyproline / Q000032:analysis; D019656:Loss of Heterozygosity / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
D016326:Extracellular Matrix Proteins; D003895:Desmosine; D004549:Elastin; D006909:Hydroxyproline