Hristova, D.

Marinov, G.

English

Varna Medical University Press: Journals

Scripta Scientifica Medica, vol.28, Suppl.1,pp.229-230 Copyright © Medical University, Varna, 1991 I N T E R C E L L U L A R C O N T A C T S B E T W E E N S M O O T H M U S C L E C E L L S IN T H E N E O I N T I M A O F T H E A U T O G E N O U S R E V E R S E D S A P H E N O U S V E I N G R A F T S D. Hr is tova , G . Mar inov Department of Anatomy, Histology and Embryology, Varna The manner of contacts between neointimal smooth muscle cells (NSMCs) of the autogenous saphenous vein grafts determine to a large extent the capability of that layer to carry out one of its basic functions - the buffer one. We studied an operation material from 10 patients with occlusive lower limb atherosclerosis in which reversed great saphenous vein had been applied for arterial bypass grafting. Material was taken during the 2 operation performed in different time intervals (7-24 months) after first one. We used routine histologi­cal and electron microscopic techniques (3). NSMCs contact each other either with their bodies or with thin projections varying in length and with different space orientation. When cells contact with their bodies (fig. 1) their basal lamines become thin or disappear and both cell membranes come closer by opposite large based cytolemmal evaginations. They form contact gaps 20-40 nm wide filled up with material of equal or higher e l e c ­tron density as c o m p a r e d to basal lamines of N S M C s named i n t e r m e d i a t e junctions (1,2). At the other parts of contact area connecting cell membranes form c o n t a c t g a p s 20-30 Д wide n a m e d n e x u s or gap junctions (2,4,5). Junct ions with­out contact gap can be seen, too. Fig. 1. NSMCs connected with their bodies ТЕМ x 30 ООО 230 NSMCs do not form b u n d l e s and they are us­ually separated by an extracel­lular mat r ix . Thus they form re lat ive ly few specilized inter­c e l l u l a r c o n ­t a c t s . W h e n NSMCs contact with their pro­jections (fig.2), they form con­tact gaps simi­larly to t h e s e d e s c r i b e d ab- Fig.2. NSMCs connected with thin projections. ove. Junctions ТЕМx 30 000 without contact gap can be seen, too. Basal lamina passes the edges of contact cell membranes from one SMC to another surrounding the contact area. In some cases it is absent and bundles of collagen fibres with longi­tudinal Space orientation can be observed in close proximity to con­tact cell membranes. Some projections connect with bodies of the adjacent NSMCs. More than two projections in different space planes can connect at the same contact area. NSMCs need certain ability to dislocate one to another to realize the neointimal buffer function des­pite the scanty elastic fibres in their extracellular matrix (3). The in­tercellular contacts must be strong to endure the dilation caused by arterial blood pressure variation . These necessities are met by foil-wing important pecularities in ultrastructure of the contacts between NSMCs: filling up of the contact gap with electron dense material; common basal lamina; additiomal strengthening of the contact by longitudinally oriented bundles of collagen fibres; direct contact be­tween the cell membranes. R E F E R E N C E S : 1. Pellegrini, M.S.F., C . Cortesini. Acta Anat., 115,1983,47-68. 2. Johnson, R.D., J .D. Sheridan. Science, 174, 1971, 717-719. 3. Marinov, G., etal . Phlebologie, 44, 1991,43-50. 4. Moore, L.K., et al. Amer. J . Physiol., 260,1991,975-981. 5. Washioka, H., et al. Arch. Histol. Cytol., 54, 1991, 181-188. 

INTERCELLULAR CONTACTS BETWEEN SMOOTH MUSCLE CELLS IN THE NEOINTIMA OF THE AUTOGENOUS REVERSED SAPHENOUS VEIN GRAFTS

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INTERCELLULAR CONTACTS BETWEEN SMOOTH MUSCLE CELLS IN THE NEOINTIMA OF THE AUTOGENOUS REVERSED SAPHENOUS VEIN GRAFTS

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