MORPHOMETRIC ASSESSMENT OF THE DERMAL MICROCIRCULATION IN PATIENTS WITH CHRONIC VENOUS INSUFFICIENCY

Purpose: Ultrastructural assessments of the dermal microcirculation in patients with chronic venous insufficiency have been limited to quali tative morphologic descriptions of venous ulcer edges or venous stasis dermatitis. The purpose of this investigation was to quantify differe nces in endothelial cell structure and local cell type with emphasis o n leukocytes and their relationship to arterioles, capillaries, and po stcapillary venules (PCVs). Methods: Two 4.0 mm punch biopsies were ob tained from areas of dermal stasis skin changes in the gaiter region o f the leg, as well as from noninvolved areas of skin in the ipsilatera l thigh, from 35 patients: CEAP class 4 (11 patients), class 5 (9 pati ents), class 6 (10 patients), and five normal skin biopsies from patie nts without chronic venous insufficiency. Electron microscopy was perf ormed on sections at 6700x and 23,800x magnification. At 6700x endothe lial cell thickness was determined, and the number of fibroblasts, leu kocytes, and mast cells were recorded relative to their proximity to a rterioles, capillaries, and PCVs. Similarly, at 23,800x endothelial ce ll vesicle density, interendothelial junctional widths, and basal lami na thickness (cuff width) were measured. Preliminary evaluation for th e presence of transforming growth factor-beta 1 (TGF-beta 1) was perfo rmed on three patients using reverse transcriptase-polymerase chain re action (RT-PCR). Results: Quantitative measurements demonstrated incre ased mast cell content for class 4 and 5 patients around arterioles an d PCVs and increased macrophage numbers for class 6 patients around PC Vs (P < 0.05). Fibroblasts were the most common cells observed; howeve r, no differences were demonstrated between groups. No differences wer e observed in interendothelial junctional widths or vesicle densities in arterioles, capillaries, or PCVs. Basal lamina thickness was increa sed only at the capillary level (p < 0.05). The results of RT-PCR for TGF-beta 1 messenger RNA were positive in the three patients studied. Conclusions: Our data suggest that (1) mast cells play a role in the p athogenesis of chronic venous insufficiency; (2) the effects of mast c ells, macrophages, or both mag. be mediated in part by TGF-beta 1; and (3) capillary cuff formation is not associated with widened interendo thelial gap junctions, but ma). be a result of enhanced vesicular tran sport rate or conformational changes in the interendothelial glycocaly x.