Characterization of aneurysmal aortas by biochemical, thermal, and dielectric techniques.
Abdominal aortic aneurysms (AAA) are characterized by structural alterations of the aortic wall resulting from the degradation of elastic fibres and an increase of collagen/elastin ratio. In this study we investigated the chain dynamics of AAA tissues by two techniques generally used for the characterization of polymers, Differential scanning calorimetry (DSC) and thermally stimulated currents (TSC), and we correlated the obtained data with biochemical analyses. The thermal denaturation of collagen observed by DSC allowed us to evaluate the thermal stability of the triple helix domain: notable modifications were evidenced between collagen from control tissue and collagen from AAA, particularly concerning the thermal denaturation. The dielectric analysis of pathologic aortic walls by TSC revealed a relevant change of collagen mobility in AAA, with the occurrence of a specific mode of relaxation between -60 and -40°C. Biochemical, thermal, and dielectric results are compatible with increase of new collagen deposition and/or impairment of the collagen phase stability in the extracellular matrix of AAAs.
Samouillan
Valerie
V
Laboratoire de Physique des Polymères, Institut Carnot, CIRIMAT UMR 5085, Université Paul Sabatier, 31062 Toulouse cedex 9, France. vsamou@cict.fr
Dandurand
Jany
J
Lacabanne
Colette
C
Stella
Andrea
A
Gargiulo
Mauro
M
Degani
Annamaria
A
Gandaglia
Alessandro
A
Spina
Michel
M
D000368:Aged; D000596:Amino Acids / Q000737:chemistry; D001011:Aorta / Q000473:pathology*; D017544:Aortic Aneurysm, Abdominal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002152:Calorimetry, Differential Scanning; D003094:Collagen / Q000737:chemistry / Q000378:metabolism; D017364:Collagenases / Q000378:metabolism; D004549:Elastin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010434:Pepsin A / Q000378:metabolism; D011489:Protein Denaturation; D013696:Temperature
D000596:Amino Acids; D003094:Collagen; D004549:Elastin; D010434:Pepsin A; D017364:Collagenases