Modulation of smooth muscle cell behaviour in culture has been associated with changes in the extracellular matrix. In the present study cultures of bovine aortic smooth muscle cells were compared in the rapidly proliferating and confluent phases of growth. The extracellular matrix was similar in both phases of growth and consisted of glycoproteins ranging from molecular weight 20,000 to over 200,000. The glycopeptides derived from these components displayed several differences. N-linked heteropolysaccharides of the biantennary and complex (more than two branches) types were predominant in the matrix of the confluent phase. Larger amounts of high mannose glycopeptides were present in the preparations from proliferating cells. O-Glycosidic glycopeptides were minor components in both preparations, but a slight increase was noted in the confluent phase of growth. Some of the changes in glycopeptides were interpreted in terms of the levels of the major components of the matrix such as the interstitial procollagens and fibronectin. The results indicate that processing of oligosaccharides associated with secreted glycoproteins of the extracellular matrix correlates with the state of growth of smooth muscle cells in culture.

The collagens of fibrous atherosclerotic lesions of human aortae obtained at post mortem examination were compared with those of normal intima-media preparations. Assessed quantitatively, pepsin-solubilized types IV, V and VI collagens decreased in relation to types I and III in preparations from lesions as compared to values for controls. The type V collagen in both tissues were composed of alpha 1 (V) and alpha 2 (V) chains in a 2:1 ratio. A novel ("V") collagen polypeptide identical in size to the alpha 1 (V) chain was identified in association with the interstitial collagen fraction in both tissue types. This chain had unique solubility characteristics and cyanogen bromide peptide composition. The exact relation of this polypeptide to the other collagens is not known, but it is possible that it accounts for the reported fluctuations in type V chains in aortic tissues.

Ultrastructural and biochemical studies were carried out on bovine aortic smooth muscle cells cultured in the presence or absence of ascorbate. In its absence, electron microscopic examination of cultures revealed that the extracellular components consisted primarily of microfibrils. Morphologically identifiable collagen fibrils were only observed in the matrix upon ascorbate supplementation. Smooth muscle cells grown in ascorbate-free media synthesized large amounts of type VI collagen. The identity of the latter was confirmed by ion exchange chromatography, slab gel electrophoresis, and amino acid analysis. Addition of ascorbate resulted in a stimulation of type I collagen production, levels of the type III remained constant, and types V and VI were decreased. Since, in the absence of ascorbate, smooth muscle cells are known to synthesize predominantly elastin, the present data support the contention that the type VI collagen and the microfibrillar component of elastic tissue are either identical or similar.

Changes in the basement membranes associated with the placenta and fetal membranes have been observed in diabetic women, but little is known about the underlying alterations at the biochemical level. Present studies are concerned with the amount, chain composition and carbohydrate content of the collagens from amniotic membranes of women with overt and gestational diabetes. Collagens were obtained from these membranes using pepsin digestion and differential salt precipitation. In comparison with controls, the amounts of the interstitial and type IV collagens remained unchanged while the type V samples showed a moderate increase. However, by the use of reduced pepsinization, a fraction containing primarily type VII collagen and some type VI showed a significant increase in the tissues from diabetics, especially those from overt patients. Slab gel electrophoresis of the latter fractions revealed increased amounts of type VII collagen chains. The collagens from diabetics showed only small and marginally significant increases in their carbohydrate content. These observations suggest that changes in the 'intermediate' collagens as a group may play a role in the connective tissue changes associated with diabetes.

The present study was undertaken to clarify the existing controversy on the collagenous content and composition of human fibrous atherosclerotic versus normal aortic tissues. Several analytic procedures (slab gel electrophoresis; cyanogen bromide peptide mapping; high performance liquid chromatography; ion exchange chromatography) revealed that the amount of the interstitial collagens, i.e. types I and III, was similar in fibrous atherosclerotic lesions and control tissues (70% and 30% respectively). Moreover, when fibrous lesions were analyzed as serial fractions there was a uniform distribution of type I and type III throughout the lesion. Small increases in type III were observed only beneath the lesion where it interfaced with the normal media. The results suggest that contrary to some previous studies no major shifts in the ratio of the interstitial collagens are evident in atherosclerotic lesions as compared to normal intima-media preparations.

Type V collagen is a major component of the pericellular coat of smooth cells (SMC). The purpose of the present study was to assess biochemically the nature of an in vitro interaction between bovine aortic SMC and type V collagen from the same source. This interaction was originally shown to be mediated by a cell-surface glycoconjugate. Data obtained in the present study suggests that the binding system consists of integral membrane glycoproteins which act alone or in combination with a surface glycolipid in type V attachment. The nature of this system was indicated by the finding of 80 000 and 50 000 components in the plasma membrane fractions which were specifically retained by type V collagen--Sepharose columns and incorporated both methionine and mannose label. Moreover, inhibition of protein synthesis lowered SMC attachment by 25%. The mannose label associated with these components was probably in the form of a simple oligosaccharide at the attachment site since it bound to concanavalin A (ConA) and was sensitive to endoglycosidase H. Iodinated ConA labelling indicated elevated levels of these components were associated with SMC--type V collagen interaction. The attachment region on the type V molecule was localized within the cyanogen bromide peptide 6 of the alpha 2 (V) chain.

Aortic type IV collagen from several species contained identical patterns of high-molecular-weight aggregates as determined by HPLC. Slab gel electrophoresis in one and two dimensions revealed a similar chain composition in these collagen samples. The basic structural components were similar in size to the long form of 7-S collagen. These studies suggest that a common supramolecular assembly of type IV chains exist within aortic basement membrane matrices.

HomeStrokeVol. 15, No. 5Collagen in cerebral aneurysms, mitral valve prolapse, and von Willebrand syndrome. Free AccessAbstractAboutSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessAbstractCollagen in cerebral aneurysms, mitral valve prolapse, and von Willebrand syndrome. R J Andrews R J AndrewsR J Andrews Originally published1 Sep 1984https://doi.org/10.1161/01.STR.15.5.917Stroke. 1984;15:917–918"Collagen in cerebral aneurysms, mitral valve prolapse, and von Willebrand syndrome.." Stroke, 15(5), pp. 917–918 Previous Back to top Next FiguresReferencesRelatedDetailsCited By Gene L, Carita T, Ryan L and Patrick Y (2020) Minimally invasive treatment of portal pseudoaneurysm in a haemophiliac after knee arthroscopy, Journal of Orthopaedics, Trauma and Rehabilitation, 10.1177/2210491720918578, 27:2, (235-239), Online publication date: 1-Dec-2020. Ricciardo B, Mwipatayi B, Abbas M, Sieunarine K and Eikelboom J (2005) von Willebrand Disease Associated with Superficial Temporal Artery Pseudoaneurysm, European Journal of Vascular and Endovascular Surgery, 10.1016/j.ejvs.2005.03.016, 30:3, (285-287), Online publication date: 1-Sep-2005. Kılıc T, Sohrabifar M, Kurtkaya Ö, Yildirim Ö, Elmaci I, Günel M and Pamir M (2005) Expression of Structural Proteins and Angiogenic Factors in Normal Arterial and Unruptured and Ruptured Aneurysm Walls, Neurosurgery, 10.1227/01.NEU.0000180812.77621.6C, 57:5, (997-1007), Online publication date: 1-Nov-2005. NAKAU R, NOMURA M, KIDA S, YAMASHITA J, KINOSHITA A, NITTA H and MURAMATSU N (2005) Subarachnoid Hemorrhage Associated With von Willebrand's Disease-Case Report-, Neurologia medico-chirurgica, 10.2176/nmc.45.631, 45:12, (631-634), . Schievink W and Levi M (1991) Management of intraventricular haemorrhage secondary to ruptured arteriovenous malformation in a child with von Willebrand's disease., Journal of Neurology, Neurosurgery & Psychiatry, 10.1136/jnnp.54.2.188-b, 54:2, (188-189), Online publication date: 1-Feb-1991. Lauzier S and Barnett H (1987) Cerebral Ischemia with Mitral Valve Prolapse and Mitral Annulus Calcification The Heart and Stroke, 10.1007/978-1-4471-3129-8_5, (63-100), . Jackson A (2015) Neurologic Disorders Associated with Mitral Valve Prolapse, Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 10.1017/S0317167100035733, 13:1, (15-20), Online publication date: 1-Feb-1986. September 1984Vol 15, Issue 5 Advertisement Article InformationMetrics Copyright © 1984 by American Heart Associationhttps://doi.org/10.1161/01.STR.15.5.917 Originally publishedSeptember 1, 1984 Advertisement

Collagenous components were extracted from bovine aorta by pepsin digestion. Differential salt precipitations separated the interstitial from the basement membrane (BM) collagens, and the latter were subsequently separated into three distinct types. Ion exchange chromatography, SDS-slab gel electrophoresis, cyanogen bromide and protease V8 peptide mapping, and amino acid analysis were used to characterize the component chains within each of these types. The major BM-class contained three distinct chains which were identical to the alpha 1(V), alpha 2(V) and alpha 3(V) chains of type V collagen from normal human placenta. The stoichiometry of the chains suggests a [alpha 1(V)]2 alpha 2(V)-helical organization, but the role of the alpha 3(V) chain in the overall structural organization of collagen V remains unknown. The second BM-class contained a heterogeneous group of molecules ranging in size from 40 000 to 140 000 daltons. Two predominant chains within this group were characterized as the alpha 1(IV) and alpha 2(IV) chains of type IV collagen. The last class of BM collagens consisted primarily of high molecular weight components; upon reduction these gave rise to two low molecular weight collagenous species (40 K and 45 K) characteristic of type VI, low molecular weight or 'linker' collagens. The functional roles of the isolated BM collagens, either individually or collectively, has not been ascertained to date.

Collagens were obtained from decalcified human embryonic calvaria by pepsin digestion. After removal of the type I collagen, the more soluble collagens were precipitated at 1.2 M NaCl (acid pH), followed by a selective precipitation step at neutral pH, using a NaCl concentration of 4.5 M. Analysis of this latter precipitate by polyacrylamide slab gel electrophoresis and ion-exchange chromatography revealed the presence of a heterogeneous group of proteins ranging in size from approximately 10 000 daltons to over 120 000 daltons. Proteolysis, as a source for these diverse components, was ruled out both by studies employing protease inhibitors and experiments employing thrombin which indicated that no helical denaturation had occurred during extraction. A comparison with standard collagen preparations suggested that the major bands present in these samples corresponded to the alpha 1-, alpha 2-, and alpha 3-chains of type V collagen. The data also showed that the major helical organization of these chains was [alpha 1(V)]2 alpha 2(V). Data suggesting that proteolysis can occur during the chromatographic separation of the individual alpha-chains are presented. This proteolysis was sensitive to inhibitors and its possible role in modifying the chain composition of type from calvaria and other tissues is discussed. Unique cyanogen bromide peptides distinguishable from those of type I and type V were present in these precipitates and suggests the presence of novel collagen types. The small amounts of these collagens precluded a determination of the exact nature of these components.