35 sulphur uptake in the mucosa adjacent to carcinoma of the large intestine

Increased faecal mucin sulphatase activity in ulcerative colitis: a potential target for treatment

Colonic mucin is heavily sulphated and it has been shown that enzymatic desulphation by faecal bacterial sulphatases greatly increases its susceptibility to degradation by faecal glycosidases. A possible role for faecal mucin sulphatase in the pathogenesis of inflammatory bowel disease has therefore been explored. Faecal mucin sulphatase activity assayed using 35S mucin as substrate was increased in ulcerative colitis (median 80.2 units/g pellet weight (range 6.9-1063; 95% confidence intervals (CI): 45.2 to 293.8, n = 22) compared with 11.3 units/g (range 3.0-53.5; 95% CI: 8.7 to 29.8, n = 17) in healthy controls (p < 0.01), where one unit released 1000 dpm free sulphate/hour from 35S mucin (1680 dpm/microgram). Patients with active ulcerative colitis had higher sulphatase activity (median 146; 95% CI: 98 to 253 units/g, n = 10) than those with inactive ulcerative colitis (median 42.2; CI: 22.5 to 81.6 units/g, n = 12) (p < 0.05). Longitudinal studies in patients with ulcerative colitis show fluctuations of faecal mucin sulphatase activity corresponding to clinical disease activity in six of seven patients. Faecal mucin sulphatase activity was not significantly increased in Crohn's disease (median 36.6, range 5.7-106.6; 95% CI: 22.9 to 65.3 units/g, n = 14). The bismuth salts, bismuth subcitrate and bismuth subsalicylate were found to inhibit faecal mucin sulphatase activity at concentrations achievable therapeutically. The increased faecal mucin sulphatase activity in ulcerative colitis could be the result of greater intraluminal substrate (mucin) availability leading to bacterial enzyme induction, but would probably result in more rapid degradation of secreted mucin and represents a potential target for treatment.

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. III. Changes in the histochemical and chemical properties of the epithelial glycoproteins in the mucosa close to colonic tumours

Histochemical, chemical and histological studies were performed on 26 specimens of human colonic tumours and 62 specimens of mucosa taken at distances of 0.5-5.0 cm from the tumour. The tumour glycoproteins were divided almost equally between three anionic types, sulphomucin, sialomucin and mixed sialomucin and sulphomucin. All showed a reduction in staining for side chain O-acylated sialic acid. In 56% of the tumours, this was accompanied by loss of glycoprotein while, in 44%, abundant mucin was still present. Histochemical examination of the mucosal specimens indicated that in 24.2% the side chain O-acylated sialic acids did not differ from normal. In 41.9% there was a focal change and in 33.9% there was a generalized field reduction in the proportion of side chain O-acyl sialic acids. The latter were subdivided into moderate and severe. Chemical analyses correlated well with the histochemical classification of the mucosal specimens and showed that, on average, the classifications focal and severe field change were not due to sampling error. Forty-five per cent of the cases showed only focal change and 40% only field change. Mucosal specimens associated with 60% of the moderately differentiated tumours showed only focal change while those associated with 75% of well-differentiated tumours showed only field change. Abnormal patterns of staining for side chain O-acylated sialic acids (a) were largely independent of the distance from the tumour, (b) occurred in the presence of a normal pattern of staining for sialomucins and sulphomucins and (c) were associated with 61.4% of the specimens that showed no discernible evidence of histological abnormality. In contrast, only one specimen showed evidence of histological change without a corresponding change in O-acylated sialic acids. The data suggest that abnormal patterns of staining for O-acylated sialic acids may represent premalignant change but their precise significance and specificity requires further studies of non-neoplastic diseases of the colon.

Uptake of [35S]sulphate in human colonic mucosa associated with carcinoma: an autoradiographic analysis at the ultrastructural level

The uptake of [35S]sodium sulphate, as a sulphomucin precursor, was studied at the ultrastructural level as part of our investigation into alterations in glycoprotein synthesis occurring in colonic mucosa adjacent to carcinoma ('transitional' mucosa). The sulphate labelling was analysed statistically after incorporation and pulse labelling studies to show the amount of uptake into cellular organelles and the rate of transport through the cells. Uptake studies showed the following changes in the 'transitional' mucosa as compared with normal mucosa. (1) In the middle crypt, sulphate incorporation from the Golgi apparatus into the mucin droplets of the goblet cells was reduced in contrast with an increased uptake into the vesicles of the absorptive and 'intermediate' cells. (2) In the upper crypt, more sulphate was incorporated in the goblet cells. These results correlate well with previous histochemical findings of a larger proportion of sulphomucins in the vesicles of columnar cells and a predominance of sialomucins in the goblet cells in the colonic mucosa associated with carcinoma. The pulse labelling studies revealed that in the middle crypt region of the 'transitional' mucosa, the rate of movement of label was faster through the Golgi body but less labelling was reaching the mucin droplets. The data suggest that either an inadequate supply of acceptor molecules was available at the Golgi level or a blockage in the attachment mechanism of the free sulphate to the completing glycoproteins was occurring at this level. Alternatively both mechanisms may be operating simultaneously.

Transitional mucosa and survival in human colorectal cancer

The mucosa in 100 segments of colon and rectum resected for cancer were examined using light microscopy and histochemical techniques. The extent of abnormal or transitional mucosa was defined for each case. Transitional mucosa was present in 93 of 95 adenocarcinomas and one malignant melanoma. The average total length of transitional change was 3.4 cm the maximum length was 19.5 cm. An inverse correlation was observed between the survival and the length of transitional mucosa around locally invasive (Dukes' B) carcinomas (P = 0.005). This may be related to increased amounts of sialic acid in transitional mucosa and the ability of sialic acid to depress tumor immunogenicity. The raised levels of sialic acids in transitional mucosa may have practical value in assessment of prognosis in colorectal cancer.

A comparison of [3H]galactose and [3H]fucose uptake with the morphological and histochemical changes observed in mucous secretion in chemically induced rat colonic carcinoma

The alterations in carbohydrate metabolism which occur in the distal colon of rats during carcinogenesis induced by dimethylhydrazine were investigated using [3H]galactose and [3H]fucose as glycoprotein precursors. A statistically significant decrease in [3H]galactose uptake was observed in dysplastic epithelia. These findings are consistent with the alterations in mucin composition with predominance of sialomucins shown in these areas by histochemical methods. Furthermore, changes in the gradient of [3H]galactose incorporation along the crypt epithelium were also found in the histological and histochemically non-involved colonic mucosa of dimethylhydrazine-treated rats, as compared with controls. No significant variations were seen in [3H]fucose incorporation. These results correlate well with our previous histochemical observations and are further evidence of the profound alterations in glycoprotein synthesis affecting the whole colonic mucosa during carcinogenesis.

A histochemical comparison of the O-acylated sialic acids of the epithelial mucins in ulcerative colitis, Crohn's disease, and normal controls

Two histochemical techniques, the PAT/KOH/PAS and the PBT/KOH/PAS, were used to investigate the side chain O-acyl substitution patterns of the sialic acids of the colonic epithelial mucins in cases of ulcerative colitis and Crohn's disease. In both diseases there was, as compared to normal, a reduction in the proportion of sialic acids O-acylated at C7C8, the reduction being greater in ulcerative colitis. Further, there appeared to be an association between the severity of the disease and the reduction in the staining of O-acylated sialic acids. This relationship was more marked in ulcerative colitis. In some cases of both diseases there was evidence for epithelial mucins containing predominantly C7-substituted sialic acids. This study has confirmed our previous conclusion that, in Crohn's disease of the terminal ileum, the disease is associated with an increase in the proportion of sialic acids bearing side chain substituents.

Mucosal hyperplasia in clonic diverticula

Benign, nonpolypoid mucosal hyperplasia has been consistently observed adjacent to colonic carcinomas. In order to determine the specificity of this association we looked for this type of mucosa in diverticulosis with or without diverticulitis, a disease thought not to be causally related to carcinoma. Nonpolypoid mucosal hyperplasis was frequently found within diverticula suggesting that this mucosal abnormality is, in some instances, unrelated specifically to malignancy.

Histochemical comparison of the epithelial mucins in the ileum in Crohn's disease and in normal controls

A comparison of routine and special histochemical methods that were applied to the epithelial mucins of small intestine from patients with Crohn's disease and from normal controls showed that the normal small intestine (ileum) goblet cells secrete a predominantly non-sulphated sialomucin and that, in contradistinction to the colon, the neuraminidase insensitivity of the sialic acids of the small intestine was not due to either O-acylation at C4 or an ester substituent at C1. Presumably this implies that the protection against enzyme attack afforded to the mucosa by the mucin coat in the small intestine utilises a different mechanism from that in the colon and that, although in many respects the small intestinal mucins in Crohn's disease, and in normal controls are similar, there is an increase in side-chain O-acylated sialic acids in such mucins in Crohn's disease. This difference has not been described before, probably because it can be seen only after staining such sections by the PAT/KOH/PAS and the PBT/KOH/PAS techniques.

Benign (nonpolypoid) mucosal changes adjacent to carcinomas of the colon. A light microscopic study of 20 cases

Numerous reports deal with the presence or absence of remnants of benign polyps adjacent to colonic carcinomas. Little attention has been paid to light microscopic mucosal alterations of a nonpolypoid nature found adjacent to these neoplasms. The general assumption has been that this mucosa is normal or not significantly altered. In this presentation we describe nonpolypoid mucosal changes found adjacent to 20 randomly selected carcinomas of the colon. We found these changes to be variably but consistently present. Their possible significance is briefly discussed.

Mucous secretion in rat colonic mucosa during carcinogenesis induced by dimethylhydrazine. A morphological and histochemical study

Our previous studies, in specimens of large intestine resected for carcinoma, have shown abnormal patterns of mucous secretion in areas of apparently "normal" mucosa, where goblet cells produce mainly sialomucins as compared with the true normal colonic mucosa in which sulphomucins predominate. In the present work, large bowel cancer was induced in rats by the administration of 1,2-dimethylhydrazine-2HCl (DMH). We attempted to study the sequential histological and secretory abnormalities which developed in the colonic epithelium during carcinogenesis, and to correlate these changes with those described above in the human. The microscopical and histological lesions observed in the colonic mucosa of DMH treated rats confirmed the findings of other authors and resembled the human colorectal cancer. The earliest changes detected were small foci of hyperplasia accompanied from the 6th week onwards by several foci of dysplasia. Carcinoma in situ appeared at the 15th week and finally invasive carcinoma developed from the 19th week onwards. Changes in the type of mucous secretion, with predominance of sialomucins, were observed in the majority of the areas showing mild to moderate dysplasia whilst the surrounding normal epithelium produced suphated material. Mucous depletion was a common feature in areas of severe dysplasia and carcinoma. These findings correlated well with the similar variations in the mucin composition observed in human colonic mucosa in carcinoma and further supported our previous hypothesis that mucin changes characterized by an increase in sialomucins might reflect early malignant transformation. If this hypothesis proved to be correct, the use of a simple method for the identification of mucins in large bowel biopsies would be of great help in detecting early malignancy.

Glycosidases in normal and dimethylhydrazine-treated rats and mice with special reference to the colonic tumours

Activities of 12 glycosidases and of β-D-glucuronidase were measured in liver, kidney and in the gastrointestinal tract of rats and mice. The activities of different enzymes varied not only within one tissue but also among different tissues. In rats injected with 1,2-dimethylhydrazine, a many fold increase in N-acetyl-β-D-glucosaminidase, N-acetyl-β-D-galactosaminidase, β-D-galactosidase and α-L-fucosidase was found in colonic tumours and colonic mucosa. These enzymes were elevated significantly in the kidney of tumour bearing animals as well. Liver and other parts of the gastrointestinal tract showed an increase only in N-acetyl-hexosaminidase with the appearance of colonic tumours. In treated mice, 2 N-acetylhexosaminidases were elevated in colon, duodenum, liver and kidney. However, in liver and kidney, β-D-galactosidase was also significantly increased.

Changes in composition of mucin in the mucosa adjacent to carcinoma of the colon as compared with the normal: a biochemical investigation

Fifteen surgical specimens from patients with carcinoma of the colon and rectum were studied. Scrapings from normal mucosa distant from the tumour and from macroscopically normal mucosa adjacent to the tumour (;transitional') were used for chemical estimation of hexosamines, sialic acid, and proteins. The presence of hexosamines and sialic acid was confirmed in both normal and transitional mucosa. Transitional mucosa showed increased levels of total hexosamines and sialic acid as compared with the normal and this was accompanied by an increase in neuraminidase-sensitive sialic acids. The present data have been compared with previous histochemical and autoradiographic studies and it is suggested that the changes described in the transitional mucosa are transformations representing an early stage of carcinogenesis.

The value of a study of the mucosubstances in rectal biopsies from patients with carcinoma of the rectum and lower sigmoid in the diagnosis of premalignant mucosa

One hundred and twenty-one rectal biopsies from 99 patients with carcinoma of the rectum or lower sigmoid colon were investigated using a high iron-diamine-Alcian blue technique for sulphated and non-sulphated acid mucins. It was found that in normal rectal mucosa sulphomucins are the main carbohydrate component of the goblet cell mucin. This normal ;mucous pattern' changes in the ;transitional' mucosa (histological normal mucosa adjacent to carcinoma) where there is an increase of non-sulphated acid mucins concomitantly with a decrease or absence of sulphated groups in 60 to 90% of the cases according to the type of tumour. The same type of changes in mucus were observed in the ;transitional' mucosa surrounding adenomatous polyps and papillary adenomas; they were not marked in areas around carcinoma in situ and not observed in the metaplastic polyps. These changes seem to be in direct relationship to the grade of differentiation and invasiveness of the tumour. The histochemical changes in the mucins seem to be in favour of a malignant potential in the so-called neoplastic polyps. The high iron diamine-Alcian blue, because of its ;specificity', consistent results, and easy technique is recommended for routine use together with haematoxylin and eosin staining in the diagnosis of premalignant changes.