The anatomy and pathogenesis of wrinkles

The anatomy of linear wrinkles ("crow's feet' and temporal frown lines), fine criss-cross wrinkles of the face and wrinkling of the general body surface of elderly persons, was studied by light and scanning electron microscopy. No histological features distinguished the various wrinkles from surrounding skin. It was concluded that the wrinkle is a configuration change, like the grooves worn into an old glove, without specific structural alterations at the histological level. As regards pathogenesis, the common setting was found to be deterioration of the elastic tissue network. The skin becomes looser, excessive, and loses the ability to snap back to its original state after being deformed.

Anatomy of striae

The histopathology of striae distensae is disputed; different authorities give contradictory accounts of the microscopic changes, especially in elastic fibres. We re-evaluated the problem by taking eight elliptical biopsies across striae. Six were examined by light microscopy with appropriate stains for elastin and collagen. Two were prepared for scanning electronmicroscopy (s.e.m.), using a procedure which removes collagen, enabling the elastic network to be seen in its native form. By light microscopy, striae were sharply demarcated from normal skin, consisting mainly of fine, straight bundles of collagen arranged parallel to the surface. Fine elastic fibres were disposed similarly without fragmentation, fraying or curling. By s.e.m., the elastic network was found to be extraordinarily dense and well developed with many fine, curled fibres in random array. It was evident that the routine stains for elastin greatly underestimated the abundance of elastic fibres, probably because immature fibres contain insufficient protein matrix. The horizontal packing of collagen bundles was confirmed by s.e.m. These findings support the view that striae distensae are scars. There is no evidence that they form by stress-induced rupture of the connective tissue.

Ultrastructural study of iron deposition in the eccrine sweat glands of patients with iron overload

An ultrastructural study of eccrine sweat glands was carried out on three patients with iron overload (two with idiopathic haemochromatosis and one with transfusional haemosiderosis). In all three patients small electron-dense particles were seen in both eccrine sweat glands and macrophages. They appeared primarily in the clear cells of the eccrine sweat glands as membrane-bound irregularly shaped bodies, and were shown to contain iron by energy dispersive X-ray microanalysis. Iron aggregates in and around sweat glands were also seen on light microscopy.

Corticosteroid atrophy in human skin. A study by light, scanning, and transmission electron microscopy

Steroid atrophy was induced in 3 volunteers by the continuous, occlusive application of clobetasol propionate to the forearms for 6 weeks. The changes were followed sequentially by light, scanning, and transmission electron microscopy. a 59% decrease in viable epidermal thickness was noted after the sixth week of treatment, as well as a flattening of the dermal-epidermal junction. The 3-dimensional architecture of the dermis was strikingly reorganized. This was largely brought about by resorption of the ground substance as revealed by a progressive diminution of Hale's stain for acid mucopolysaccharides. Loss of ground substance resulted in decreased spaces between collagen and elastic fibers as shown by scanning and transmission electron microscopy. The fibrous network consequently collapsed, yielding a more compact papillary and reticular dermis. This compression caused the reorientation of both collagen and elastic fibers. However, no differences in collagen and elastin fine structure were noted. Fibroblasts were shrunken but not reduced in density. A marked decrease in number of mast cells was noted in 3-week specimens and virtually no mast cells were observed after 6 weeks. We found that the primary effect of short-term steroid use was a rearrangement of the geometry of the dermal fibrous network. This was not due to alterations in the fibers themselves but a secondary consequence of the loss of ground substance.