Cronkhite-Canada syndrome with adenomatous and carcinomatous transformation of colonic polyp.

We describe a 70-year-old woman who presented with watery diarrhea and was found to have gastric and colonic polyposis, cutaneous hyperpigmentation, alopecia and onychodystrophy (Cronkhite-Canada syndrome). Histology of a polyp from the stomach showed features of juvenile or retention type (hamartomatous) polyp. One colonic polyp revealed features of tubular adenoma, with moderate dysplasia. Another large pedunculated colonic polyp showed a tubulovillous adenoma with a focus of well-differentiated adenocarcinoma confined to the submucosa of the stalk. Adenomatous and carcinomatous epithelial changes can occur in Cronkhite-Canada syndrome.     

Secondary amyloidosis of human colonic mucosa

Summary Histochemical and electron microscopic studies were performed on colonic mucosa obtained by biopsy from a patient with severe diarrhea as the initial symptom of secondary amyloidosis. Congo red-positive amorphous material which showed dichroic birefringence when examined under the polarizing microscope was found in perivascular areas, among muscle bundles of the muscularis mucosae, and in large amounts beneath the surface epithelium. Amyloid deposits surrounding small blood vessels and intermixed with the muscularis mucosae contained typical fibrils as well as membrane-bound amorphous material suggestive of sacs of rough-surfaced endoplasmic reticulum. In some areas amyloid fibrils appeared to be continuous with the limiting membranes of vascular smooth-muscle cells and fibroblasts.Ultrastructural abnormalities not recognized by light microscopy were present in the microvillous borders of surface epithelial cells overlying large amyloid deposits. These microvillous abnormalities suggest that the cells had a decreased absorptive capacity and therefore contributed to the patient's severe diarrhea.Supported by grants from the John A. Hartford Foundation, Inc., New York, and from the Edward G. Schlieder Foundation, New Orleans; and by US Public Health Service Grants 5-S01-FR-05377, NB-04330, and HE-06100; and by Research Career Development Award NB-K3-16731 (Dr. Harkin).Presented in part at the Fifth Annual Microscopy Symposium of the Louisiana Society for Electron Microscopy, New Orleans, Feb 1, 1968.     

In situ detection of enterocytic apoptosis in normal colonic mucosa and in familial adenomatous polyposis.

Physiological regeneration of colonic epithelium entails proliferation at the crypt base and cell loss by shedding or cell death. The aim of this study was to localise and assess the rate of apoptosis in normal and neoplastic colonic epithelium with respect to zones of proliferation. Familial adenomatous polyposis (FAP) was chosen as a model to study neoplastic transformation of colonic mucosa at an early stage. Apoptotic cells were detected in situ by TdT-mediated biotin-dUTP nick end labelling (TUNEL) in parallel to cells in cycle determined by Ki-67 immunohistochemistry using the monoclonal antibody MiB-1. By detection of genomic fragmentation, two different patterns of enterocytic apoptosis emerged: (a) apoptotic bodies being engulfed by adjacent epithelial cells, and (b) apoptotic cells with only subtle morphological changes being extruded into the gut lumen. The engulfment pattern was seen predominantly in the crypts of the normal colonic mucosa and, although very rare, was clearly confined to the basal proliferation compartment. The extrusion pattern was restricted to the luminal mucosal surface. Adenomas of FAP showed highly increased numbers of apoptotic bodies, which were scattered throughout the transformed mucosa. Both patterns of apoptosis were topographically intermingled although the extrusion pattern prevailed at the luminal adenoma surfaces. Whereas cells in cycle were somewhat more numerous in the upper parts of the crypts, apoptosis occurred with increased frequency at sites beneath the proliferation maximum suggesting an inverted direction of epithelial cell migration in adenomas. These results suggest two distinct routes towards enterocytic apoptosis in the colonic mucosa leading to engulfment or extrusion of dying cells. Adenomatous transformation of colon epithelium is associated with a considerable increase of the cellular turnover rate and with a severe disturbance of the microtopographical localisation of birth and death of enterocytes.     

Hormone-sensitive adenylate cyclase in human colonic mucosa

Human colonic adenylate cyclase has been shown to be sensitive to vasoactive intestinal polypeptide (VIP) and prostaglandins of the E- and F-type. Maximal activation of enzyme activity averaged 200% for VIP and 300-350% for the E-prostaglandins. Both classes of hormones had an additive effect on enzyme activity indicating the existence of two distinct hormone-sensitive adenylate cyclases in human colonic mucosa.     

Inward growth of colonic adenomatous polyps

BACKGROUND & AIMS: Most colon cancers arise from polypoid adenomas, but how these benign lesions develop into malignant neoplasms is not understood. This study examined the migration of epithelial cells within human adenomatous polyps by determining the distribution of proliferating and apoptotic cells and immunoreactivity to transforming growth factor beta (TGF-beta). METHODS: Sections of surgically resected normal (n = 10) and adenomatous (n = 22) formalin-fixed tissue were examined for proliferating cells and TGF-beta isoenzymes 1-3 by immunohistochemistry and apoptotic cells by terminal deoxyuridine nick end-labeling. RESULTS: The distribution of proliferating, apoptotic, and TGF-beta immunoreactive cells was strikingly reversed in adenomatous polyps compared with normal mucosa. Proliferating cells were located in the base of normal colonic crypts and TGF-beta immunoreactive and apoptotic cells near or at the luminal surface, corresponding to the normal migration of colonocytes. In adenomas, increased numbers of proliferating cells were mainly located at the luminal surface and TGF-beta immunoreactive and apoptotic cells were located principally at the crypt base. CONCLUSIONS: This distribution suggests that cell migration in adenomas is not toward the lumen but instead inward toward the polyp base. (Gastroenterology 1996 Dec;111(6):1425-32)     

Rapid epithelial restitution of human and rabbit colonic mucosa

Rapid epithelial restitution is now considered one of the primary defense mechanisms of the stomach and duodenum. Because there is currently no evidence as to whether restitution occurs in human tissue, this study examined human and rabbit colonic mucosa after superficial injury and monitored the potential difference, alkaline flux, and speed and mechanisms of mucosal restitution as observed with light and electron microscopy. Luminal exposure of the in vivo rabbit colon to 100 mM HCl for 5 min or the in vitro human colon to 10 mM HCl for 10 min caused superficial mucosal injury to 76% of the epithelial surface in the rabbit and 95% in the human. The necrotic epithelial cells detached in sheets from the intact basal lamina and formed a protective mucoid layer. Morphologic evidence of restitution occurred within 15 min after injury in the rabbit and 30 min in the human, as viable nongoblet cells projected lamellipodia and migrated over the denuded basal lamina at a speed of approximately 2 microns/min. One hour after damage 61% of the mucosal surface was still damaged in the rabbit, and 86% of the human mucosal surface was damaged after 2 h. In the following 60 min restitution progressed rapidly, so that only 10% of the surface remained unrepaired in the rabbit after 2 h and 19% in the human after 3 h. Small areas with deeper injury did not repair until 5 h after damage. The potential difference dropped after mucosal injury and did not recover despite morphologic repair. Rapid epithelial restitution is considered to be a basic defense mechanism of the gastrointestinal mucosa that is obviously not necessarily related to the presence of an acidic environment in the stomach or duodenum.     

Differences in laser-induced autofluorescence between adenomatous and hyperplastic polyps and normal colonic mucosa by confocal microscopy

Laser-induced autofluorescence has been used to discriminate normal from adenomatous colonic mucosa. However, few studies to date have studied the origin of colonic autofluorescence. Using confocal microscopy (excitation wavelength 488 nm), we have shown that autofluorescence at this wavelength is present predominantly in the lamina propria of normal mucosa but in the epithelium in adenomatous and hyperplastic polyps. The intensity ratio of epithelial cell to lamina propria fluorescence was significantly lower (P<0.0001) in normal mucosa (0.52±0.01) compared with either adenomatous (1.6±0.2) or hyperplastic polyps (1.7±0.15). However, the ratios were not significantly different between hyperplastic and adenomatous polyps. Thus, confocal microscopy enables the detection of the sites of autofluorescence within colonic mucosa and the quantitation of differences in fluorescence between different tissue types.     

Location of superoxide anion generation in human colonic mucosa obtained by biopsy.

To identify which cells generate superoxide, inflamed human mucosa was tested with nitro-blue tetrazolium as a probe, because it is reduced by strong reducing agents to form insoluble blue formazan, which then precipitates in tissues. Biopsy specimens from control subjects and patients with ulcerative colitis were studied. The specimens were organ cultured with bubbling air or nitrogen, and inhibition of the reduction by catalase (a hydrogen peroxide scavenger), para-benzoquinone (a tissue permeable superoxide scavenger), or superoxide dismutase (a superoxide scavenger) was assayed. The dye was reduced by epithelial cells, vascular endothelium, and infiltrating mononuclear cells of the mucosa. Its reduction by vascular endothelium and infiltrating mononuclear cells was greater in inflamed mucosa. The reduction by vascular endothelium and infiltrating mononuclear cells was inhibited in cultures with nitrogen saturation or with 1 mM para-benzoquinone. The vascular endothelium seems to produce superoxide in the inflamed mucosa, which would exacerbate tissue injury in ulcerative colitis.     

Importance of the surrounding colonic mucosa in distinguishing between hyperplastic and adenomatous polyps during acetic acid chromoendoscopy

AIM： To examine the characteristics of colonic polyps, where it is difficult to distinguish adenomatous polyps from hyperplastic polyps, with the aid of acetic acid chromoendoscopy. METHODS： Acetic acid spray was applied to colonic polyps smaller than 10 mm before complete excision. Endoscopic images were taken before and 15-30 s after the acetic acid spray. Both pre- and post-sprayed images were shown to 16 examiners, who were asked to interpret the lesions as either hyperplastic or adenomatous polyps. Regression analysis was performed to determine which factors were most likely related to diagnostic accuracy. RESULTS： In 50 cases tested by the 16 examiners, the overall accuracy was 62.4% （499/800）. Regression analysis demonstrated that surrounding colonic mucosa was the only factor that was significantly related to accuracy in discriminating adenomatous from hyperplastic polyps （P 〈 0.001）. Accuracy was higher for polyps with linear surrounding colonic mucosa than for those with nodular surrounding colonic mucosa （P 〈 0.001）, but was not related to the shape, location, or size of the polyp. CONCLUSION： The accuracy of predicting histology is significantly related to the pattern of colonic mucosa surrounding the polyp. Making a histological diagnosis of colon polyps merely by acetic acid spray is helpful for colon polyps with linear, regularly patterned surrounding colonic mucosa, and less so for those with nodular, irregularly patterned surrounding colonic mucosa.     

Nuclear DNA content of isolated crypts of background colonic mucosa from patients with familial adenomatous polyposis and sporadic colorectal cancer.

The DNA content of the upper one third of the crypt epithelium was compared with that of the lower two thirds in the background colorectal mucosa of eight cases of familial adenomatous polyposis (FAP) and eight control cases of sporadic colorectal cancer (SCRC). Intact crypts were isolated by incubating fresh lesion free colorectal mucosa in calcium and magnesium free Hanks' balanced salt solution (CMFH) containing 30 mM EDTA for 30 minutes at 37 degrees C and then agitating in CMFH. The crypts were then separated from the lamina propria, fixed in 70% ethanol and under a dissecting microscope divided manually into upper and lower portions. Each portion was digested with pepsin to obtain a suspension of single nuclei, and smears of the nuclei were stained with 4',6,-diamidino-2-phenylindole dihydrochloride (DAPI). Nuclear DNA was determined using a cytophotometric microscope. Results showed that the DNA content of the epithelium of the upper one third of crypts was diploid in both FAP and SCRC cases, and that proliferative fractions with diploid peaks were present in the lower two thirds of the crypts in both groups. These results support our previous finding that the proliferative compartment of background crypts is confined to the lower two thirds and does not extend to the upper parts of the crypts.     

Interleukin-13 inhibits nitric oxide production in human colonic mucosa

BACKGROUND/AIMS: Nitric oxide synthesis is increased in rectal biopsies from patients with ulcerative colitis and colonic epithelial cells are considered to be a major source of nitric oxide in intestinal inflammation. METHODOLOGY: Human colonic biopsies from normal bowel mucosa and colonic epithelial cell line HT-29 were cultured in the presence of the inflammatory cytokines IL-1 alpha + TNF-alpha + IFN-alpha added after 1 hour pretreatment with vehicle or Interleukin-13. Nitrite levels were determined at 30 hours in culture supernatants by a fluorometric assay. RESULTS: Unstimulated human colonic biopsies and HT-29 cells produced a basal amount of nitrite. Stimulation with IL-1 alpha + TNF-alpha + IFN-alpha induced a significant (P < 0.001) increase of nitrite generation by both human colonic biopsies and HT-29 cells. The presence of Interleukin-13 produced a significant (P < 0.001) suppression of the cytokine-induced nitrite generation from both colonic biopsies and HT-29 cells. CONCLUSIONS: Nitric oxide generation in human colonic mucosa is susceptible to manipulation by proinflammatory cytokines. Interleukin-13 has an inhibitory effect on cytokine induced nitrite production in colonic mucosa and could play an anti-inflammatory role in intestinal inflammation.     

Bacteroides fragilis toxin 2 damages human colonic mucosa in vitro

BACKGROUND: Strains of Bacteroides fragilis producing a 20 kDa protein toxin (B fragilis toxin (BFT) or fragilysin) are associated with diarrhoea in animals and humans. Although in vitro results indicate that BFT damages intestinal epithelial cells in culture, the effects of BFT on native human colon are not known. AIMS: To examine the electrophysiological and morphological effects of purified BFT-2 on human colonic mucosa in vitro. METHODS: For resistance (R) measurements, colonic mucosa mounted in Ussing chambers was exposed to luminal or serosal BFT-2 (1.25-10 nM) and after four hours morphological damage was measured on haematoxylin and eosin stained sections using morphometry. F actin distribution was assessed using confocal microscopy. RESULTS: Serosal BFT-2 for four hours was four-, two-, seven-, and threefold more potent than luminal BFT-2 in decreasing resistance, increasing epithelial 3H-mannitol permeability, and damaging crypt and surface colonocytes, respectively (p<0.05). Confocal microscopy showed reduced colonocyte F actin staining intensity after exposure to BFT-2. CONCLUSIONS: BFT-2 increases human colonic permeability and damages human colonic epithelial cells in vitro. These effects may be important in the development of diarrhoea and intestinal inflammation caused by B fragilis in vivo.     

A case of cancerous familial adenomatous polyposis in urinary bladder due to migration of colonic mucosa through rectovesical fistula

The patient was a 50-yr-old man who had undergone low anterior resection for rectal cancer at the age of 24 yr in 1966. At that time, gastric and colonic polyposis were indicated. Postoperative anastomotic dehiscence occurred and, by 1985, a rectovesical fistula had formed. In 1986, when the patient was 44 yr old, he was examined at our hospital for constriction of the rectum due to the rectovesical fistula. Abdominoperineal excision of rectum and surgical closure of the fistula were performed, and the patient was kept under observation because of a diagnosis of familial adenomatous polyposis. In 1988, when the patient was 46 yr old, early ascending colon cancer was discovered and total colectomy was performed. Then, in December, 1991, gross hematuria was found. Further examination revealed a tumor on the posterior wall of the urinary bladder lumen, and biopsy showed adenocarcinoma. Pelvic recurrence of the rectal cancer was diagnosed, and total pelvic exenteration was performed. There were no distant metastases; histologically, the tumor of the bladder was thought to be due to colonic mucosa of familial adenomatous polyposis that had migrated to the bladder lumen via the rectovesical fistula and had become cancerous.     

Functional and phenotypical activation of leucocytes in inflamed human colonic mucosa

Infiltrating leucocytes are activated to generate reactive oxygen species or to produce several molecules in inflamed colonic mucosa. To clarify the phenotypical and functional properties of activating cells in colitic mucosa, 23 patients with ulcerative colitis and 13 controls were studied using a combined method for determining in situ nitroblue tetrazolium reducing activity and immunohisto-chemical characterization. Antibodies 25F9 (anti-macrophage), EG2 (anti-eosinophil cationic protein), MAC387 (anti-calprotectin, expressed by activated myeloid-histiocytes lineage), and MAC-1 (anti-CD11b) were used. The proportion of EG2, calprotectin, and CD11b-positive cells were significantly increased in inflamed mucosa. The proportion of EG2, calprotectin, and CD11b-positive cells significantly correlated with the histological degree of inflammation. Proportion of EG2-positive cells but not calprotectin nor CD11b-positive cells was significantly correlated with nitroblue tetrazolium reducing activity. Aggregated cells reducing nitroblue tetrazolium seen in severely inflamed mucosa were found to be EG2 positive. Most of the calprotectin-positive cells were 25F9 negative. In addition to activation of neutrophils and macrophages, eosinophil activation has been shown to be involved in inflamed colonic mucosa.     

Effect of water irrigations on human colonic mucosa structure after sigmoidostomy

The colonic mucosa of patients with sigmoidostomies, who were operated on for rectal cancer, and treated thereafter for different periods of time with daily water irrigations to obtain complete evacuation, was investigated by histologic and histochemical methods. Microscopic examination of the test specimens showed that the epithelial continuity, the characteristic brush border, and the positive mucous reaction to PAS and Alcian blue-Alcian yellow methods were not significantly changed with respect to controls. In some test specimens a remarkable number of mitoses were evident in the crypts. Since this could result from water irrigation stimuli and/or might represent an early manifestation of a restoved carcinogenetic process, specific investigations were performed on the 0-acylated sialic acids of the colonic mucins, which have been reported to represent markers of early malignant changes in colorectal epithelial cells. The results did not reveal alterations of the sialomucins in the treated specimens with respect to controls. Read at the XXI Concegno Società Italiana di Istochimica, Capri, Italy, May 21 to 23, 1986.     

Alterations in human colonic mucin occurring with cellular differentiation and malignant transformation.

The binding of fluorescein isothiocyanate (FITC)-conjugated lectins to mucin in the human colon was studied by using fluorescence microscopy. In normal mucosa, lectins that preferentially bind to exposed N-acetyl-galactosamine residues (Dolichos biflorus agglutinin and soybean agglutinin) bound selectively to the goblet cell mucin of well-differentiated cells in the upper colonic crypt. By contrast, lectins that require exposed non-reducing galactose residues for binding (Ricinus communis agglutinin1 and Bauhinia purpurea agglutinin) preferentially labeled the mucin of less-differentiated goblet cells located in the lower portion of the colonic crypt. The lectin derived from Arachis hypogaea (peanut agglutinin) has a high affinity for a carbohydrate structure not normally exposed in human tissues. This lectin did not label the goblet cell mucin in the normal colon. However, the mucin was labeled in all 21 colon cancer specimens examined. Additionally, the nonmalignant epithelium immediately adjacent to colon cancer (termed "transitional mucosa") also contained goblet cell mucin that was labeled by FITC-peanut agglutinin. Three conclusions may be drawn from the selective binding characteristics of FITC-lectins to colonic mucins. First, an alteration in the exposed, nonreducing carbohydrate residues occurs in human colonic mucin during the process of goblet cell differentiation. Second, an exposed carbohydrate structure that is not normally present in human tissues is expressed in the mucin produced by malignant colonic epithelium. Third, the presence of the cancer-associated carbohydrate structure in the mucin of transitional mucosa suggests that this tissue may be in the process of early malignant transformation.