ABSTRACT
This chapter provides a comparison on two types of aging: that of the dermis for undifferentiated supportive connective tissue and that of the aortic wall for specialized connective tissue. In these two tissues, the fibroblasts in the one and the smooth muscle cells (SMC) in the other ensure the secretion of the various identical interstitial components, their maintenance by slow turnover, and intervene in low-density lipoproteins (LDL) metabolism. In aging, major changes within connective components of the dermis are observed: collagen loses its regular and fascicular appearance and the fibroblast cell population becomes "at rest". The dermal connective tissue in young and old subjects is described before analyzing cultured young and aged fibroblasts and the morphological variations that fibroblasts may present during life. By light microscopy, dermis aging is characterized by the progressive disappearance of oxytalan fibers, by the progressive dystrophy and lysis of elaunin and elastic fibers, and by changes in the morphology of collagen bundles.
