Age-related changes in composition and mechanical properties of the tunica media of the upper thoracic human aorta.

摘要: A cylindrical segment, free of complex atherosclerotic lesions, was resected at autopsy from each 59 descending human thoracic aortas by cutting just below the level first pair intercostal arteries and 35 mm distal to this incision. Each isolated tunica media defatted subjected successive treatment with EDTA-Tris, 5 M guanidine hydrochloride-Tris, hydrochloride-Tris-DTE, collagenase either trypsin or hot alkali. After extraction digestion, dimensions weight segments were measured extracted materials analyzed quantitated. This allowed total content various components be assessed both gravimetric analytical means. An age-related rise observed in following components: proteins glycoproteins soluble chaotropic solvents (ranging 24 mg/cm youngest samples 46 oldest) collagen (38 69 mg/cm). In contrast, elastin remained constant 70 all ages, but its concentration decreased due other tissue as thickened age. It also noted that increasing age there an accumulation protein(s) which could not solubilized agents collagenase, removed Mechanical measurements conducted before after digestion on previously purification four used suggest accumulated influenced elastic response applied stress incremental modulus, breaking stress, hysteresis. removal additional protein(s), mechanical behavior component found identical samples, irrespective is therefore proposed morphological changes stiffening aging aortic wall are degradation network variations supramolecular organization connective components.