[Vascularization of the matrix of hyaline rib cartilage in the human: changes with increasing age]

A correlative light microscopic/transmission electron microscopic study was performed on human hyaline costal cartilage material of variable age (group I: first postnatal month; group II: second decade, and group III: fifth, sixth and seventh decades of life; total: nine cartilage samples) in order to clarify and evaluate the existence and dimensions of a vascular supply in young hyaline cartilage matrix and to compare with alterations or changes, respectively, occurring with aging. Human postnatal hyaline costal cartilage (4th to 6th rib) is vascularized very early by centripetally running venous/arterial vessels invading from the perichondrium. This process seems to be an active one since endothelial spurs and capillary sprouts could be demonstrated. During the middle decades of life a drastic/substantial decrease in amount/appearance of vessels or vascular supply, respectively, of the cartilage generally seems to occur. From the third/fourth decade on up to higher decades neovascularization seems to be a constant finding, especially in degeneration areas: so-called marrow spaces of cartilage matrix. With increasing age the fibrillar perivascular matrix becomes thicker, resulting in a so-called collagen-collar which consists of highly oriented collagen fibrils/fibers (as compared with the attaching extracellular cartilaginous matrix), most probably newly synthesized by (mesenchymal/fibrocytic/specialized?) cells accompanying the invading vessels. Incidence and possible function of the structures found in aged human costal cartilage are not fully understood; the ultrastructural changes compared with postnatal costal cartilage, however, are evident and demonstrated.