Structural abnormalities in the dermal collagen and elastic matrix from the skin of patients with inherited connective tissue disorders

Abstract

Skin from patients with inherited disorders of connective tissue metabolism (EDS Types I-IX, Marfan's syndrome, osteogenesis imperfecta, spondyloepiphyseal dysplasia, and cutis laxa) has been examined by light and transmission electron microscopy for defects in the collagen and elastic connective tissue which may explain the clinical disorder and/or correlate with the biochemical defect (where known). Alterations were observed in the organization of the dermis and in the individual collagen and elastic fibers. The major alterations observed among collagen fibrils were hieroglyphic-shaped fibrils, collagen flowers, unravelled fibrils and fibrils of normal shape but abnormally large or small diameters or a mixed population of both. Elastic fibrils were sometimes fragmented, highly branched, granular, densely stained and had inclusions suggestive of cellular debris. These changes appeared to be a consequence of degradative processes. Other fibers were seen with a paucity of elastin matrix associated with the microfibrils or with totally separate deposition of the two elastic fiber components. Such fibers were barely visible by light microscopy. Alterations were observed in tissue concurrently regardless of whether the biochemical defect was related to only one of these connective tissue structures. The observations support an hypothesis that alterations in one component of the connective tissue matrix may influence the deposition and structure of others, ultimately, modifying the overall organization and mechanical properties of the tissue.