[Immunohistochemical characterization of collagen in liver cirrhosis (author's transl)]

A comparative study of PAS-phosphotungstic acid-Diamine Supra Blue FGL and immunological reactions for type I collagen

Immunohistochemical techniques proved valuable in histological studies of various types of collagens. However drawbacks include non-specific reactions of antibodies, masking of antigens, and the high cost of antibodies. This study was undertaken to ascertain the specificity of the PAS-phosphotungstic acid-Diamine Supra Blue FGL (PAS-PTA-DSB-FGL) reaction for type I collagen, differentiating it from other collagens. Duplicate series of methacarn-fixed sections of various tissues were treated with the PAS-PTA-DSB FGL reaction and the peroxidase-antiperoxidase (PAP) technique for type I collagen and the staining patterns were compared. Fibers binding the blue dye were found only at sites reacting with antibodies against type I collagen. These observations indicate that the PAS-PTA-DSB FGL procedure is suitable for visualization of type I collagen, e.g. in screening of large series of sections and in the practice of surgical and autopsy pathology.

Distribution of collagen types I and III and basal lamina in human gastric carcinoma: an immunohistochemical and electron microscopic study

Collagen types I and III were examined immunohistochemically in 32 cases of gastric carcinoma classified as poorly differentiated adenocarcinoma with scirrhous stroma, well differentiated adenocarcinoma with intermediate stroma, or poorly differentiated adenocarcinoma with medullary stroma. In the stroma of scirrhous carcinoma, types I and III collagens were distributed abundantly in fibrillar or granular patterns with little difference in the intensity of staining. In well differentiated adenocarcinoma, type I collagen was diffusely distributed in the stroma with type III collagen distributed sparsely. In poorly differentiated adenocarcinoma with medullary stroma, the two types of collagen were only found around capillaries, constituting the tumor interstitium. Electron microscopic examination of scirrhous carcinoma showed tumor cells partially covered with fibroblasts, and discontinuous basal lamina, collagen fibers and microfibrils present between tumor cells and fibroblasts. In well differentiated carcinoma, tumor cells were surrounded by fibroblasts, and well developed basal lamina was observed beneath the tumor cells. In poorly differentiated carcinoma with medullary stroma, the stroma consisted of capillaries and very few fibroblasts with discontinuous basal lamina occasionally being present between tumor cells and fibroblasts.

Distribution of collagen types I, III, and V in fibrotic and neoplastic human liver

The distribution of collagen types I, III, and V in normal and fibrotic human livers and hepatocellular carcinoma was studied by indirect immunofluorescence procedure using type specific antibodies. Type I collagen as well as type III collagen was present in normal liver within the portal tracts and along the perisinusoidal spaces. Basement membrane collagen, type V collagen, was demonstrated only around the bile ducts and vessels of the portal tracts and central veins. In fibrotic liver, both type I and III collagens were found in increased amounts in fibrotic areas. In fibrous septa of active cirrhosis, however, type I collagen as well as type III collagen was abundant, whereas in inactive cirrhosis type I fibers were predominant. Type V collagen was observed in the walls of proliferative bile ductules and vessels in the fibrotic liver, and also along the sinusoids in the periportal areas. In hepatocellular carcinoma, each type of collagen was distributed regularly along the sinusoid-like vascular channels within the tumor.

Tipos de colágeno na fibrose hepática esquistossomótica de Symmers

Os AA. estudaram o tipo de colágeno em cortes histológicos de fragmentos de fígado de 12 indivíduos portadores da forma hepatesplênica da esquistossomose mansoni, pela técnica de coloração pelo Sirius Supra Red F3BA. Como controle usaram cortes histológicos de 12 fragmentos de fígado de indivíduos sem doenças fibrosantes. As preparações coradas pelo Sirius Supra Red F3BA e examinadas em microscópio de polarização (Leitz) revelaram que a fibrose periportal é constituída por colágeno de tipos I e III, com predominância do primeiro.

Light microscopic distinction of collagens in hepatic cirrhosis

Histochemical studies by Sesta et al. (1965) demonstrated in hepatic cirrhosis an embryonic-type collagen that differs from reticulum fibers. Grimaud and coworkers observed type IV collagen in cirrhotic lesions. To determine whether or not this collagen can be visualized by light microscopy, sections fixed in Carnoy-type solutions were treated with the periodic acid -Na bisulfite - resorcin-fuchsin (PBRF) reaction for basement membranes. Reticulum and coarse (Type I) collagen fibers were visualized with picro-Sirius Red F3BA. In normal livers, basement membranes occurred only around bile ducts and blood vessels. In hepatic cirrhosis basement membrane-like material extended from septa into nodules. The reaction patterns were similar to immunofluorescence pictures of Type IV collagen. The ratios of different collagens varied widely and were apparently determined by type and of lesions and other factors. For further studies, improved light microscopic reactions are needed, especially for simultaneous demonstration of embryonic and basement membrane-type collagens in contrasting colors.

Distribution of fibronectin in the rectal mucosa

Fibronectin is a glycoprotein of high molecular weight present in tissues, plasma, and tissue fluids. Its distribution in the rectal mucosa was studied by immunofluorescent and immunoperoxidase techniques using a monospecific antiserum. Immunofluorescent reactivity for fibronectin was present in the normal rectal mucosa of control subjects in epithelial cells, on basement membranes, and as a loose cribriform network of extracellular reactivity in the lamina propria that codistributed with histochemically demonstrable reticulin. Fibronectin was demonstrated immunoelectromicroscopically on collagen fibres, on smooth muscle cells and within and between columnar epithelial cells. In the rectal mucosa of patients with colitis with marked inflammatory changes, fibronectin appeared thickened and more prominent when present on basement membranes and as sparse strands between inflammatory cells infiltrating the lamina propria. In patients with longstanding colitis and less inflammatory cell infiltration there was a diffuse increase in fibronectin which was densely and uniformly present throughout the lamina propria. Fibronectin is a structural component of the rectal mucosa and changes in its distribution may form an important part of the local reaction to inflammatory bowel disease.

Silver impregnation methods for reticulum fibers and reticulin: a re-investigation of their origins and specificity

Maresch (1905) introduced Bielschowsky's silver impregnation technic for neurofibrils as a stain for reticulum fibers, but emphasized the nonspecificity of such procedures. This lack of specificity has been confirmed repeatedly. Yet, since the 1920's the definition of "reticulin" and studies of its distribution were based solely on silver impregnation technics. The chemical mechanism and specificity of this group of stains is obscure. Application of Gomori's and Wilder's methods to human tissues showed variations of staining patterns with the fixatives and technics employed. Besides reticulum fibers, various other tissue structures, e.g. I bands of striated muscle, fibers in nervous tissues, and model substances, e.g. polysaccharides, egg white, gliadin, were also stained. Deposition of silver compounds on reticulum fibers was limited to an easily removable substance; the remaining collagen component did not bind silver. These histochemical studies indicate that silver impregnation technics for reticulum fibers have no chemical significance and cannot be considered as histochemical technics for "reticulin" or type III collagen.

[Rational use of bone marrow biopsy. longitudinal hemisection of samples, for simultaneous adaption of various histological preparations without loss of material (author's transl)]

Unfortunately, the combination of the superior histologic embedding technique for semi-thin sectioning of undecalcified bone in methacrylate with special methods in enzyme or immune histochemistry did not prove to be very successful up to now. These shortcomings are attributed to the influence of the embedding medium itself. They can be overcome by processing one part of a biopsy specimen after embedding in methacrylate, the other one after freezing. Optimal and comparable results have been obtained by a simple instrument for longitudinal hemi-sectioning of a cylindrical biopsy specimen of cancellous bone of adequate size, and by developing a suitable technique for the cutting of frozen sections of undecalcified bone. These methods are presented. Examples are given of the benefits of the simultaneous evaluation of one and the same biopsy-specimen with light-microscopic, ultramicroscopic, enzyme- and immun-histochemic technique.

Collagen polymorphism in normal and cirrhotic human liver

Collagens in normal human liver and in alcoholic cirrhotic liver were investigated. Collagens were solubilized by limited proteolysis with pepsin under nondenaturing conditions, and after purification, were fractionated into types I and III by selective precipitation with NaCl. After carboxymethyl cellulose and agarose chromatography, the resulting alpha-chains from each of the collagen types were analyzed with respect to their amino acid and carbohydrate compositions. A comparison of the results obtained from normal liver with those from the diseases organ revealed no significant differences. The isolated human liver alpha1(I) and alpha1(III) chains were digested with CNBr and the generated peptides were separated and purified by a combination of ion-exchange and molecular sieve chromatography. The molecular weight and the amino acid and the carbohydrate compositions of each of the peptides were identical to those of the corresponding human skin peptides except for the slightly higher content of hydroxylysine in some of the peptides. The relative content of type III in relation to type I collagen in both normal anc cirrhotic liver was determined by digesting washed liver homogenates directly with CNBr and quantitating the resultant alpha1(I) and alpha 1(III) peptides after chromatographic separation. The relative quantities of these peptides indicated that normal human liver contained an average of 47% type III, with the remainder being type I. Cirrhotic liver, on the other hand, contained a significantly smaller proportion of type III, ranging from 18 to 34% in different samples, with a corresponding increase in type I. These findings indicate that although the amino acid and carbohydrate compositions of collagens deposited in cirrhotic liver are normal, the fibrotic process of alcoholic liver disease in humans is accompanied by an alteration in tissue collagen polymorphism, and suggest that the observed alterations may have pathogenetic implications.

Increase in type I and type III collagens in human alcoholic liver cirrhosis

Collagen in bulk was isolated in about 30% yield from the livers of normal human beings and from livers of persons with alcholic cirrhosis. Analyzed chemically and examined by electron microscopy, the collagen in each case was shown to consist of two types identical with, or resembling closely, type I and type III collagens of skin. The collagen from normal liver was predominantly type I, whereas, that from cirrhotic livers consisted or approximately equal amounts of the two types. By chromatography on carboxymethyl-cellulose, the type I collagen from the cirrhotic livers showed one alpha2chain and two alpha1 chains. The alpha1 chains were separable from one another, but gel electrophoretic patterns of peptides obtained from them after treatment with CNBr were almost identical, and resembled the pattern obtained with CNBr peptides of the alpha1 chain of rat skin type I collagen. The increased collagen of both types was responsible in part for the observed distortion of the architecture of the cirrhotic livers associated with increased rigidity of the stroma. The predominance of type III collagen in the areas of collapse of architecture where, as shown by others, few fibroblasts are present, suggests that hepatocytes might have an important function in fibrogenesis during the course of liver cirrhosis.