STRUCTURAL AND BIOCHEMICAL-ALTERATIONS OF HUMAN DIABETIC DERMIS STUDIED BY H-3-LYSINE INCORPORATION AND MICROSCOPY

  • 1 January 1976
    • journal article
    • research article
    • Vol. 24  (5) , 329-336
Abstract
The alteration of the structural organization of dermal connective tissue was studied by light microscopy and EM and by biochemical techniques in normal human and in diabetic patients using skin biopsies. Part of the tissue was used for light microscopy and EM; the rest was incubated in the presence of 3H-lysine for 4 h. The 3H-lysine labeled biopsies were submitted to a sequential extraction procedure in order to obtain representative macromolecular fractions containing the matrix macromolecules. The extracts were analyzed for their chemical composition and radioactivity. EM revealed ultrastructural modifications of the fibroblasts, and of the collagen and elastic fibers in the diabetic dermis. Fibroblasts contained an increased amount of electron dense deposits in the cytoplasm and dilated endoplasmic reticulum. The collagen bundles were dissociated. Elastic fibers under the epithelial basal laminae were fragmented or absent. The incorporation pattern of 3H-lysine into these macromolecular fractions was different in the normal and diabetic skin biopsies. The percentage of total radioactivity incorporated increased significantly in the 1M CaCl2 extractable fraction and in the 6M urea extractable fraction and decreased significantly in the collagenase and elastase extracts in diabetic skin biopsy. These results demonstrate the existence of morphological and biochemical alterations in diabetic connective tissue (dermis), reflecting alterations in the relative rates of synthesis and/or degradation of the intercellular matrix macromolecules and of their microarchitectural arrangement.

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