Prostaglandin E2-induced colonic secretion in patients with and without colorectal neoplasia

Background  

The pathogenesis for colorectal cancer remains unresolved. A growing body of evidence suggests a direct correlation between cyclooxygenase enzyme expression, prostaglandin E₂ metabolism and neoplastic development. Thus further understanding of the regulation of epithelial functions by prostaglandin E₂ is needed. We hypothesized that patients with colonic neoplasia have altered colonic epithelial ion transport and express functionally different prostanoid receptor levels in this respect.     

Methylation status of p16 gene in colorectal carcinoma and normal colonic mucosa

INTRODUCTIONp16gene(als0knownasMTS-l,INK4a,CDKN2A),locatedonchromos0me9p21,isaG1-specificcell-cycleregulatorygene.Itiscomposedofthreeex0ns,whichenc0de156aminoacids[l].Thegeneisfrequentlyinactivatedinmanyhumancancers-Unlike0thertumor-suppress0rgenesthatarecommonlyinactivatedbypointmutations,smallhom0zygousdeletionsandmethylationoftheprom0terrepresentthemajormechanismofp16geneinactivati0n[2'3].IntheWesternc0untries,colorectalcarcinomaranksfirstamongmalignanttumors.Themortalityfromcolor…     

Changes in colorectal function in patients with chronic colonic pseudoobstruction

Motility studies of the lower bowel, radiology to exclude other gastrointestinal involvement, and rectal biopsies were carried out in 11 patients, age 21–60 years, with isolated chronic colonic pseudoobstruction. Repeated plain abdominal x-rays during symptomatic periods revealed massive gaseous colonic distension in all. Seven patients had the primary form while four patients had an underlying disease which could have been responsible for the chronic colonic pseudoobstruction. Lower bowel motility was decreased in patients with the primary form. Rectal wall elasticity was increased in both the primary and secondary form. Some of the abnormalities measured may suggest myogenic abnormalities of the sigmoid or rectal wall. No specific neural or muscular morphologic defect was identified in colonic transmural sections in eight patients except in the patient with Hirschsprung's disease. Five of seven patients with primary colonic pseudoobstruction achieved symptomatic relief only after subtotal colectomy and ileoproctostomy.This project was supported by the National Institutes of Health grants AM 25965 and M01-RR-00059 from the General Research Center Program, Division of Research Resources.     

Cyclic AMP and cyclic GMP levels in human colonic mucosa before and during chenodeoxycholic acid therapy.

Previous experimental studies suggest that bile salt-induced colonic fluid secretion is mediated by adenosine 3':5'-phosphate (cyclic AMP). Two biopsy specimens of colonic mucosa were obtained endoscopically before and after different periods of therapy (five, 10, or 15 days), from each of 21 patients receiving chenodeoxycholic acid. A rise of cyclic AMP intracellular levels was found, but only after five and 10 days of treatment was the increase statistically significant when compared with basal levels. Similar changes were observed for guanosine 3':5'-phosphate (cyclic GMP), but percentage increases were higher than for cyclic AMP. Initial diarrhoea disappeared spontaneously, and at 15 days the levels of both cyclic nucleotides were not significantly different from basal levels. Our findings suggest that colonic adaptation to increase in luminal bile salt levels is related to changes in intracellular levels of cyclic nucleotides and support the hypothesis that not only cyclic AMP, but also cyclic GMP may play an important role in producing bile salt-induced diarrhoea in man.     

Nephrogenous cyclic AMP in primary hepatocellular carcinoma patients with or without hypercalcaemia

OBJECTIVE: To study the relationship between the excretion of nephrogenous cyclic AMP (NcAMP) and other blood and urine parameters as an index of PTH-like activity in patients with primary hepatocellular carcinoma. DESIGN: After overnight fast, a double voided urine and a blood sample were collected from each subject for determination of various analytes and results compared between various groups. PATIENTS: Fifty-five consecutive untreated patients with primary hepatocellular carcinoma, 14 healthy controls and eight patients with cirrhosis only. MEASUREMENTS: Serum calcium, phosphate, alkaline phosphatase, albumin, creatinine and urinary calcium, creatinine and hydroxyproline were measured by routine methods. cAMP was measured in plasma and urine by a radioimmunoassay (Diagnostic Products Corporation) and PTH measured in serum by an immunoradiometric assay (Nichols Institute). TmP/GFR, NcAMP etc. were calculated according to various published methods. RESULTS: Four out of 55 patients (7%) with primary hepatocellular carcinoma had hypercalcaemia. These four patients had significantly lower (P less than 0.05) phosphate, PTH and TmP/GFR and elevated NcAMP (P less than 0.001) compared with normocalcaemic hepatocellular carcinoma and cirrhotic patients, and healthy controls. The excretion of hydroxyproline and calcium was significantly elevated (P less than 0.001) in the hypercalcaemic patients. Bone resorption was found to be the major cause of hypercalcaemia in three of the four hypercalcaemic patients. Fifteen hepatocellular carcinoma patients (29%) with normocalcaemia had suppressed PTH. CONCLUSION: We conclude that a PTH-like humoral factor such as PTH related peptide is the cause of hypercalcaemia in patients with primary hepatocellular carcinoma, and that in some normocalcaemic patients with this tumour PTH is suppressed.     

Increase of mitotic activity in the colonic mucosa of patients with colorectal cancer

A histologic and histochemical study of the colonic mucosa, including a study of the mitotic index, was performed in routinely processed specimens from control and tumor-bearing patients. A significant increase in the mitotic index (number of mitosis×1000 gland cells), without concomitant modifications in the distribution of mitotic figures along the crypt depth, in mucosal thickness, or in mucin secretion, was demonstrated in the colonic mucosa of patients with colonic or rectal cancer compared with controls. The results point to an accelerated cell renewal in the colonic mucosa of tumor-bearing patients compared with the controls, without concomitant dysplasia. Results are discussed in the light of the possibility that an increased cell proliferation may have preceded the onset of tumor and played a role in the second step of carcinogenesis,i.e., tumor promotion, independently of dysplasia.     

Relationship of hydrolase activities to epithelial cell turnover in distal colonic mucosa of normal rats

BACKGROUND: The relationships between changes induced by diet in colonic epithelial kinetics and in the activities of brush border hydrolases are poorly defined. The aims of this study are to define these relationships, as changes in kinetics would be expected to influence differentiation, and to determine whether the type of ingested dietary indigestible carbohydrates influences hydrolase activities. METHODS: Groups of eight rats were fed a low fibre diet +/- supplements of different types of indigestible carbohydrates for 4 weeks. Alkaline phosphatase (ALP) and dipeptidyl peptidase IV (DPPIV) activities and epithelial kinetics were measured in distal colonic mucosa. RESULTS: Median ALP activities correlated positively and DPPIV activity negatively with the median proportion of cells entering metaphase (r = 0.58 and -0.58, respectively; P < 0.05) and number of metaphase arrests per crypt column across the diets (r = 0.59 and 0.58, respectively; P < 0.05). Stepwise regression analysis showed that both hydrolases independently predicted these kinetic indices (R2 > 63% for each). Mucosal ALP activities were markedly elevated during consumption of raw potato starch, guar gum and methylcellulose, while only potato starch caused a significant elevation of DPPIV activities. CONCLUSIONS: The type of indigestible carbohydrate in the diet influences colonic mucosal hydrolase activities. The opposite relationship between kinetics and each of the two hydrolases indicates that these hydrolases do not reflect the same event; dipeptidyl peptidase IV might relate to differentiation status while ALP could also be influenced by epithelial irritation due to changes in luminal conditions.     

Flow cytometric analysis of DNA synthetic phase fraction of the normal appearing colonic mucosa in patients with colorectal neoplasms.

DNA synthetic (S) phase fractions of normal appearing colonic mucosa in Japanese and British patients with colorectal neoplasms were compared with those in patients without colonic neoplasms. Normal crypts were isolated from fresh surgical specimens of the large intestine by the use of EDTA. After fixation with 70% ethanol, isolated crypts were digested with pepsin into single nuclei suspensions. These were stained with propidium iodide and examined by flow cytometry. S phase fraction was calculated from the flow cytometry DNA histogram using Baisch's method. S phase fractions of normal appearing crypts in Japanese and British patients with colorectal tumours were not significantly different and analysed together. S phase fraction of normal appearing colonic crypts in 14 patients with familial adenomatous polyposis (FAP) was 10.23 (2.59%) (mean SD)) ranging from 5.8 to 18.8. S phase fraction of background normal mucosal in patients with large adenomas (over 2 cm) and adenocarcinomas were 9.74 (3.76%) (range, 2.7-16.1) and 8.93 (3.54%) (range, 2.9-18.9) respectively. In normal mucosa of patients without any colorectal neoplasms, S phase fraction was 8.99 (3.94)% (range, 3.9-17.7). There was no statistically significant difference in S phase fractions of normal mucosa in the four groups. Our results show that an increase in proliferative activity of background colonic crypts is not necessary for tumour development.     

Histologic study of colonic mucosa in patients with chronic diarrhea and normal colonoscopic findings

BACKGROUND: There are controversies about the importance of biopsies of normal colon mucosa in the investigation of patients with chronic diarrhea. STUDY: Colonic and terminal ileum biopsies of 167 patients were reviewed. In 5 patients, used as controls, colonoscopy was done due to family history of colon cancer. RESULTS: The 5 patients without symptoms had no histologic abnormalities. The histologic findings in 162 patients with chronic diarrhea were as follows: 110 patients (67.9%) with normal histology, microscopic colitis not otherwise specified, and isolated small granulomas; 17 (10.5%) patients had findings of borderline diagnostic significance, including possible collagenous colitis, some features of lymphocytic colitis and melanosis coli; and 35 (21.6%) patients, with diagnostic significant histologic findings as collagenous colitis, lymphocytic colitis, minimal change microscopic colitis, eosinophilic colitis, pericrypt eosinophilic enterocolitis, intestinal spirochetosis, schistosomiasis, and Crohn's disease. Of the 52 patients with either borderline or significant diagnostic abnormalities, in 8 (15.4%) the diagnosis was done only with a proximal study (ascending, transverse, or descending colons). CONCLUSIONS: Histologic lesions of possible diagnostic value could exist in 32.1% of chronic diarrhea patients with normal colonoscopy, which can justify, in certain cases, mucosa biopsies, which might contribute for a more precise etiologic diagnosis; also, the distribution of these histologic changes has pointed out the importance of having all colon segments biopsied.     

Narrative review: screening for colorectal cancer in patients with a first-degree relative with colonic neoplasia

Many patients and providers are aware that colorectal cancer (CRC) "runs in families." A patient with 1 first-degree relative with CRC has approximately twice the personal risk for CRC as a similar person without this family history. Colorectal cancer is the third most common type of cancer in the United States. When providers neglect to collect information on family history, they may fail to appropriately tailor recommendations for screening for CRC for many patients. This review considers the existing data and summarizes an evidence-based approach to the common clinical problem of how and when to implement screening for CRC in a patient with a family history of colonic neoplasia. The authors discuss the varying risks for CRC given the patient's age, health habits, and personal and family histories. In the context of a clinical case that focuses on the effect of a single affected first-degree relative, the authors weigh the risks and benefits of various screening alternatives and briefly address chemoprevention, genetic testing, and future directions in screening for CRC.     

Immune response to JC virus T antigen in patients with and without colorectal neoplasia

JC virus (JCV) is a polyomavirus that infects approximately 75% of the population and encodes a T antigen (T-Ag) gene, which is oncogenic and inactivates the p53 and pRb/p107/p130 protein families. Previous work in our lab has identified the presence of T-Ag in colorectal neoplasms. While JCV remains in a latent state for the majority of those infected, we hypothesized that a disturbance in immunological control may permit JCV to reactivate, which may be involved in the development of colorectal neoplasia. Our aim was to determine the cell mediated immune response to JCV T-Ag, and determine if it is altered in patients with colorectal adenomatous polyps (AP) or cancers (CRC). Peripheral blood mononuclear cells (PBMCs) isolated from the blood of patients undergoing colonoscopy or colorectal surgery were stimulated by a peptide library covering the entire T-Ag protein of JCV. Cytokine production and T cell proliferation were evaluated following T-Ag stimulation using Luminex and flow cytometry assays. JCV T-Ag peptides stimulated secretion of IL-2, which induced T cell expansion in all three groups. However, stronger IL-10 and IL-13 production was seen in patients without colorectal neoplasms. IP-10 was produced at very high levels in all groups, but not significantly differently between groups. Most patients exhibited CD4⁺ and CD8⁺ T cells in response to stimulation by the T-Ag clusters. The combination of IL-2 and IP-10 secretion indicates the presence of T-Ag-specific Th1 cells in all patients, which is higher in patients without carcinoma.     

Elevated nephrogenous cyclic AMP with normal serum parathyroid hormone levels in patients with lung cancer

Total and nephrogenous urinary cyclic AMP (cAMP), serum Parathyroid Hormone (PTH) and ionized calcium (Ca) levels were determined in 8 normal subjects, and 16 normocalcemic and 9 hypercalcemic patients with lung cancer. Total and nephrogeneous cAMP levels were significantly increased in both normocalcemic and hypercalcemic lung cancer patients, as compared to normal subjects. There was no significant correlation between serum PTH and total or nephrogenous cAMP in the cancer group. The factors responsible for the elevated nephrogenous cAMP in the lung cancer patients are not known.     

Increased levels of insulin-like growth factor binding protein-2 in sera and tumours from patients with colonic neoplasia with and without acromegaly

OBJECTIVE: Patients with acromegaly are at increased risk of developing colorectal carcinoma and premalignant tubulovillous adenoma. The pathogenesis of these neoplasms could involve a stimulatory effect of serum growth factors on colonic epithelial cell proliferation. The aim of this study was to evaluate changes in (1) serum IGF-I, IGF-II, IGFBP-3 and IGFBP-2 and (2) changes in local expression of IGFBPs and p53 in colonic epithelium in patients with colonic neoplasia with and without acromegaly. DESIGN: A cross-sectional retrospective study was performed. Fasting serum samples were obtained at the time of colonoscopy for patients with acromegaly and at the time of surgery for patients with colonic neoplasia without acromegaly. MEASUREMENTS: Serum IGF-I, IGF-II, IGFBP-2 and IGFBP-3 were measured using specific immunoassays. Tissue expression of IGFBP-2, IGFBP-3 and p53 status were determined by immunohistochemistry. PATIENTS: Group 1: 26 age- and sex-matched control subjects (range 40-69 years); group 2: 18 patients with acromegaly without colonic neoplasia (range 39-68 years); group 3: 18 patients with acromegaly and colonic neoplasia (range 41-74 years, 11 = adenoma, seven = carcinoma); group 4: 19 patients with colonic neoplasia without endocrine disease (range 43-91 years, four = adenoma, 15 = carcinoma). Immunohistochemical staining of colonic biopsies was performed for IGFBP-2, IGFBP-3 and p53 in groups 3 and 4. RESULTS: Mean serum IGF-I and IGFBP-3 levels were significantly elevated in group 2 (371 +/- 131 microg/l and 6.5 +/- 1.8 mg/l, respectively) and group 3 (379 +/- 174 microg/l and 5.8 +/- 1.6 mg/l, respectively), and significantly reduced in group 4 (103 +/- 36 microg/l and 2.4 +/- 1 mg/l) compared to controls (165 +/- 40 microg/l and 4.7 +/- 1 mg/l; P < 0.0001, P < 0.001, respectively). However, median serum IGFBP-2 levels were significantly elevated in group 3 (P < 0.01) and group 4 (P < 0.0001). Immunostaining for IGFBP-2 showed strong areas of immunoreactivity in the cytoplasm of malignant colonic epithelium compared to benign epithelium. IGFBP-3 immunostaining showed strong areas of immunoreactivity in the cytoplasm and in the nucleus of malignant and benign colonic epithelium compared to the normal epithelium. Nuclear staining for p53 was observed in three patients from group 3 (two carcinoma, one adenoma) and four patients from group 4 (all carcinoma). CONCLUSION: Our results describe changes in IGFBP-2 expression in colonic neoplasia in patients with and without acromegaly, which suggest that this binding protein may regulate local bioavailability of IGF, which in turn could modulate colonic cell proliferation and/or differentiation.     

Lectin binding patterns in normal and neoplastic colonic mucosa

The cellular distribution of the carbohydrates labeled byDolichos biflorus agglutinin (DBA), peanut agglutinin (PNA), and wheat germ agglutinin (WGA) were studied in 21 normal colonic mucosae, 17 transitional mucosae, 9 nonneoplastic polyps (NNP), 27 adenomas, and 25 colorectal carcinomas. In normal mucosa DBA bound selectively to mucin of the goblet cells in the upper colonic crypt and to apical cytoplasm of the superficial columnar cells with a strong linear pattern. PNA binding was present only in the supranuclear portion (Golgi area) of the cells. WGA showed a strong reactivity in the goblet-cell mucin and in the supranuclear portion and apical cytoplasm of columnar cells. Transitional mucosa (TM) showed a decrease in DBA binding to goblet-cell mucin, which was replaced by an increase in PNA reactivity. The DBA linear pattern in the apical cytoplasm of columnar cells was unmodified, however. Changes similar to those of TM were observed in juvenile and Peutz-Jeghers polyps. Adenomas showed a progressive loss of DBA reactivity and an increase in PNA positivity related to the degree of dysplasia. This change was more evident in the linear pattern of apical cytoplasm. Only 32% of the carcinomas reacted with DBA and those were mucinous and well-differentiated adenocarcinomas. WGA was positive in all carcinomas with a different pattern than in normal mucosa. These findings suggest that the different lectin-binding patterns in normal and neoplastic colonic mucosa are related to the degree of cellular differentiation. In the process of malignant transformation the carbohydrate distribution undergoes progressive changes through the adenoma-carcinoma sequence. These changes are related to the degree of dysplasia in adenomas and to the degree of differentiation in carcinomas. Supported in part by the grant “Ayuda a la Investigación del Fondo de Investigaciones Sanitarias del Instituto Nacional de la Salud No. Exp. 87/1091”.