Neo-regeneration of urinary bladder: a desired metaplasia of autologous membrane from rectosigmoid colon containing stem cells of intestinal crypts

The current management of diseases of urinary bladder requiring resection is by augmentation cystoplasty or transplantation of ureters. Transplantation of ureters is associated with morbidity and mortality. Ideal management will be by regenerating urinary bladder in vivo. Neo-regeneration of tissues and organs like abdominal wall, aponeurosis etc., has been attempted and patented. After neo-regeneration of mesoderm tissues and organs, regeneration of urinary bladder (developed from endoderm) was. In vivo surgical techniques were developed in dogs. It is known that the embryonic morphogenesis of urinary bladder is from uro-genital sinus of hind gut. A membrane, containing endoderm stem cells in crypts of recto-sigmoid colon, was surgically isolated and colonized with remnant of urinary bladder wall after extensive resection. Experimental study was performed in dogs, for 60 days to one and a half year. Regeneration of all the layers of tissues of the wall of urinary bladder was observed. The neo-regeneration phenomenon has been recognized as "desired metaplasia". The regenerated neo tissue/organ on histological examination and cystometry studies was found compatible with normal urinary bladder. The hypothesis, neo-regeneration and desired metaplasia, is discussed.

Dihydroxy bile acids increase mucosal permeability and bacterial uptake in human colon biopsies

OBJECTIVE

Bile acids in mM concentrations are known to increase chloride secretion and alter mucosal permeability in animal colon. Increased mucosal permeability is believed to play an important role in the development of intestinal inflammation. The aim of this study was to investigate the influence of microM concentrations of dihydroxy bile acids on permeability and bacterial uptake in the normal human colon.

MATERIAL AND METHODS

Endoscopic biopsies from the sigmoid colon of 18 subjects with normal colonic histology were mounted in modified Ussing chambers. Chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) were added to the mucosal compartment. Short-circuit current (Isc) and transepithelial resistance (TER) were studied for 120 min. Cr-EDTA and horseradish peroxidase (HRP) were used to assess paracellular and transcellular permeability, respectively. The transmucosal passage of chemically killed Escherichia coli was quantified and investigated using confocal microscopy.

RESULTS

A significant decrease in TER was seen after 60 min of exposure to 1000 micromol/l CDCA and DCA. The combination of E. coli and 100 micromol/l CDCA gave a decrease in TER compared to controls (p = 0.06). DCA showed a dose-related increase in Cr-EDTA permeability, which was most pronounced at 1000 micromol/l (p = 0.02). Increased E. coli uptake was induced by 500 micromol/l (p = 0.01) and 1000 micromol/l CDCA (p = 0.04). Bacterial uptake was increased at 100 micromol/l by exposure to DCA (p = 0.03). Confocal microscopy revealed the presence of E. coli bacteria in the lamina propria after 15 min of exposure to 1000 micromol/l CDCA and DCA.

CONCLUSIONS

Our study suggests that dihydroxy bile acids in microM concentrations alter barrier function in normal human colon biopsies, causing increased antigen and bacterial uptake; thereby bile acids may contribute to the development of intestinal inflammation.

A novel role of VIP in colonic motility function: induction of excitation-transcription coupling in smooth muscle cells

BACKGROUND & AIMS

Vasoactive intestinal polypeptide (VIP) relaxes smooth muscle by generation of cAMP and activation of protein kinase A (PKA). However, PKA activation also phosphorylates the transcription factor CREB. The aim of this study was to investigate whether the phosphorylation of CREB induces gene expression of the pore-forming alpha(1C) subunit of Ca(v)1.2 channels (L-type calcium channels), whose promoter has 2 binding sites for CREB.

METHODS

The experiments were performed on primary cultures of human colonic circular smooth muscle cells and freshly obtained human and rat colonic circular muscle strips.

RESULTS

The incubation of human colonic circular smooth muscle cells or muscle strips with VIP for 24 hours enhanced the expression of alpha(1C) protein and mRNA as well as the contractile response to acetylcholine and KCl. On the contrary, incubation of the muscle strips with VIP antagonist for 24 hours suppressed cell contractility. The incubation of the cells with VIP caused sustained generation of cAMP for 24 hours, but PKA activation and CREB phosphorylation were transient. The inhibition of PKA by H-89 or silencing of CREB gene with targeted RNAi blocked the transcription of alpha(1C). Progressive 5' deletions of halpha(1C)1b promoter and site-directed mutations of the 2 CREB binding cis-elements indicated that most of alpha(1C) transcription was mediated by the 5' cAMP response element.

CONCLUSIONS

The excitation-transcription coupling stimulated by VIP induces expression of the Ca(v)1.2 channels. The influx of calcium through these channels is a critical step in excitation-contraction coupling in smooth muscle cells.

Decreased interstitial cells of Cajal in the neorectum after anterior resection of the rectum

BACKGROUND/AIMS

Patients who have undergone anterior resection for rectal carcinoma often complain of anorectal and defecatory dysfunction postoperatively. The aim of this study was to examine the expression of interstitial cells of Cajal (ICCs) in the sigmoid colon used for constructing the neorectum after anterior resection of the rectum.

METHODOLOGY

As the neorectum group, we assessed 12 patients with local and anastomotic recurrence or new neoplasm in the neorectum after anterior resection of the rectum. The control group consisted of 16 patients who underwent sigmoid colon resection for sigmoid colon carcinoma. All resected specimens were investigated with immunohistochemical staining, using c-kit antibody for ICCs. The correlation between the number of ICCs and defecatory symptoms was assessed for the neorectum.

RESULTS

The total number of ICCs significantly decreased in the neorectum group as compared to the control group. In particular, a significant difference was noted between the two groups as to the number of ICCs found between the layers of the myenteric plexus in histological studies, as well as in the circular and longitudinal muscles. There was no correlation between the number of ICCs and the time interval from the initial anterior resection to the resection of the neorectum, nor was there any relationship between the number of ICCs and defecatory symptoms.

CONCLUSIONS

The expression of ICCs in the neorectum was reduced in the early stages after anterior resection of the rectum. Expression of ICCs in the neorectum did not recover to preoperative levels over time.

In vivo recording of colonic motility in conscious rats with deficiency of interstitial cells of Cajal, with special reference to the effects of nitric oxide on colonic motility

BACKGROUND

We recorded in vivo colonic motility in rats with a deficiency of interstitial cells of Cajal (ICC) (Ws/Ws rats) and in wild-type rats (+/+ rats), with special reference to the effects of nitric oxide (NO) on colonic motility in both types of rats, in order to ascertain the role of ICC in colonic motility, and the relationship between NO and ICC in regard to colonic motility.

METHODS

Miniature strain-gauge force transducers were sutured on the surface of the ascending and sigmoid colon of Ws/Ws rats and +/+ rats as controls. After 1 week and a fasting period of 24 h, colonic motility in +/+ and Ws/Ws rats was recorded. We also studied the effect of NO on colonic motility in both types of rats, by means of the administration of N-nitro-L-arginine methyl ester (L-NAME) or L-arginine.

RESULTS

In +/+ rats, there were contractions with high amplitude and long duration in both the ascending and sigmoid colon. The number, amplitude, and duration of contractions in the ascending colon were 9.9/20 min, 6.1 g, and 22.7 s, respectively. These findings in the sigmoid colon were 5.2/20 min, 5.2 g, and 23.0 s, respectively. The number of contractions in the ascending and sigmoid colon in Ws/Ws rats (2.3 and 1.0/20 min) was significantly lower than that in +/+ rats (P < 0.05). The number of contractions in the ascending and sigmoid colon in +/+ rats (9.7 and 5.1/20 min before treatment) was significantly increased by L-NAME administration (28.7 and 13.9/40-60 min after treatment; P < 0.05), but that in Ws/Ws rats was not influenced. The number of contractions in the ascending and sigmoid colon in +/+ rats (10.2 and 5.2/20 min before treatment) was significantly decreased by L-arginine administration (3.6 and 2.1/40-60 min after treatment; P < 0.05), but that in Ws/Ws rats was not influenced.

CONCLUSIONS

ICC must be related to the occurrence of a normal number of colonic contractions. NO may be involved in the inhibitory regulation of colonic motility, and the effect of NO on the occurrence of contractions appears to be mediated by ICC.

Aerosol transfer of bladder urothelial and smooth muscle cells onto demucosalized colonic segments for porcine bladder augmentation in vivo: a 6-week experimental study

PURPOSE

In a pilot study we developed a cell transfer technology for populating demucosalized colonic segments with bladder urothelium. This process was achieved through aerosol transfer of a single cell suspension consisting of bladder urothelial cells, smooth muscle cells and fibrin glue onto demucosalized colonic segments. We further evaluate this new concept in a controlled study.

MATERIALS AND METHODS

The study was performed on 20 piglets (20 kg). In all animals 50% of the bladder with excised, and a 10 cm segment of the sigmoid was isolated. Animals were then equally divided into 5 groups of 1) colocystoplasty only, 2) demucosalized colocystoplasty, 3) demucosalized colocystoplasty plus covering of the demucosalized sigmoid with fibrin glue only, 4) aerosol application of fibrin glue with single cell suspension of urothelial cells only to the demucosalized colon, and 5) aerosol application of fibrin glue with urothelial and smooth muscle cells to the demucosalized colon. The 4 corners of the augmented segments were marked with 5-zero polypropylene sutures. Animals were sacrificed 6 weeks later and the surface area of the augmented segment was measured. Segments were submitted to histological and immunohistochemical analysis.

RESULTS

The surface area of the augmented segments showed an increase in group 1 animals, stabilization in groups 4 and 5, and marked reduction in groups 2 and 3. On hematoxylin and eosin, and Masson trichrome staining all group 1 animals showed normal colonic epithelium of the augment. All animals in groups 2 and 3 showed excessive scarring with urothelial coverage only at the augment periphery, while the central augment area showed no epithelium. Segments from groups 4 and 5 showed confluent epithelial covering with no fibrosis. There was no evidence of colonic epithelial re-growth in any animal in groups 2 to 5. Cytokeratin 7 and uroplakin III staining demonstrated complete coverage of the augmented segment with urothelium only in groups 4 and 5.

CONCLUSIONS

The addition of aerosolized cells of urological origin is a viable augmentation approach that appears to achieve the much sought after inhibition of intrinsic fibrosis and contraction of colonic segments when incorporated into the urinary tract without this cellular component. Moreover, this technique appears to provide a histologically normal, confluent urothelium, which sets the stage for prevention of the well-documented biochemical aberrations inherent in augments containing gastrointestinal epithelium. While successful in this model regardless of the incorporation of urological smooth muscle cells, chronic studies are now warranted to validate the short-term results as well as determine whether the urological mesenchymal population (smooth muscle) will be required to sustain the uroepithelial phenotype in the long term.

Polyethylene glycol versus sodium phosphate in bowel cleansing for colonoscopy: a randomized trial

BACKGROUND AND STUDY AIMS

There have been conflicting results regarding the adverse effects of established bowel cleansing regimens. The aim of the present study was to compare the effects of three bowel cleansing regimens on subjective well-being, electrolyte balance, cardiac arrhythmia, and the microscopic post-cleansing appearance of the colonic mucosa.

PATIENTS AND METHODS

A total of 231 consecutive outpatients were randomly assigned to receive bowel preparation for colonoscopy with either 4 l polyethylene glycol (PEG; group I, n = 76); 2 l PEG plus 10 mg Bisacodyl (group II, n = 71); or 90 ml sodium phosphate (group III, n = 84). After bowel preparation, the participants completed a questionnaire on symptoms. Endoscopists blinded to the regimen used gave scores for the quality of cleansing at endoscopy, ranging from poor (0) to very good (5). Blood samples were taken before and after bowel cleansing, electrocardiographic monitoring was used during colonoscopy, and mucosal biopsy samples were taken in the sigmoid colon.

RESULTS

Bowel preparation in group II was poorer (mean score 3.26) than in groups I (3.88) and III (4.01); P < 0.001 (II vs. III), P < 0.001 (I vs. II). The frequency of arrhythmias and post-cleansing mucosal inflammation was similar in all three groups. Lower serum potassium and higher serum phosphate concentrations were found in group III in comparison with the other groups ( P < 0.001).

CONCLUSIONS

No differences were detected regarding the effectiveness and safety of bowel preparation with PEG alone and sodium phosphate in individuals without cardiac, renal, or hepatic failure, despite a significantly stronger alteration of the electrolyte balance with sodium phosphate.

Endoscopic biopsies in Ussing chambers evaluated for studies of macromolecular permeability in the human colon

OBJECTIVE

Studies of mucosal permeability to protein antigens in humans are limited to in vitro techniques. The use of surgical specimens for such studies has major shortcomings. Endoscopic biopsies in Ussing chambers have been introduced as a means of studying secretion and transepithelial permeability, but have not been evaluated for studies of protein antigen uptake in human intestine.

MATERIAL AND METHODS

Standard forceps biopsies from the sigmoid colon of 24 healthy volunteers were mounted in Ussing chambers with an exposed tissue area of 1.76 mm2. 51Cr-EDTA (paracellular probe) and horseradish peroxidase (HRP; 45 kDa protein antigen) were used as permeability markers. Mucosal permeability, electrophysiology, histology and energy contents of the biopsies were studied over time. To evaluate the ability of the technique to detect permeability changes, the mucosa was modulated with capric acid, a medium-chain fatty acid, known to affect tight junctions.

RESULTS

In the Ussing chamber the mucosal biopsies were viable for 160 min with stable levels of ATP and lactate, and only minor changes in morphology. Steady-state permeability with low variability was seen for both markers during the 30-90 min period. Exposure to capric acid induced a rapid decrease in short-circuit current (Isc) and a slower reversible decrease in transepithelial resistance (TER), as well as an increased permeability to 51Cr-EDTA and HRP.

CONCLUSIONS

Endoscopic biopsies of human colon are viable in Ussing chambers and are reliable tools for studies of mucosal permeability to protein antigens. The technique offers a broad potential for studies of mucosal function in the pathophysiology of human gastrointestinal diseases.

Decreased interstitial cells of Cajal in the sigmoid colon of patients with slow transit constipation

BACKGROUND AND AIMS

Slow transit constipation (STC) is a colonic motor disorder that is characterized by measurably delayed movement of materials through the colon. Although abnormalities in the neuronal networks of the colon have been demonstrated in patients with STC, the etiology of STC remains unclear. Interstitial cells of Cajal (ICC) have been shown to be the pacemaker cells of the intestine and have been implied in the pathogenesis of a number of gastrointestinal motility dysfunctions, including idiopathic STC. This study aimed to determine the normal distribution of ICC within the colon of the Chinese and also to determine if ICC are decreased in Chinese STC patients.

PATIENTS AND METHODS

Twelve patients with STC and eight age-matched normal controls were studied. Specimens of sigmoid colon were obtained immediately after resection. ICC were identified with a monoclonal antibody to c-kit by an indirect immunofluorescence method. Immunostained tissues were examined with a laser scanning confocal microscope and the area occupied by ICC was calculated with an image analysis system.

RESULTS

ICC were located in the external muscle layers including myenteric plexus (MP) and submucosal border (SMB). Two types of Kit-positive ICC were observed: bipolar cells characterized by one or two long processes and multipolar cells characterized by long stellate processes extending in various directions. A higher percentage of ICC was present in the MP regions and circular muscle (CM) layers compared with the SMB and longitudinal muscle (LM) layers. Tissues from STC patients showed a considerable decrease in the number of ICC located in the four regions (ICC-LM, ICC-MP, ICC-CM, ICC-SMB), especially the ICC-SMB, in which ICC almost completely disappeared.

CONCLUSIONS

Similar distribution of ICC was observed in the normal sigmoid colon of the Chinese. Decreased area of c-kit+ ICC may play an important role in the pathophysiology of STC. It remains to be determined whether the loss of ICC is primary or secondary to another lesion.

A role for chromogranin A (4–16), a vasostatin-derived peptide, on human colonic motility. An in vitro study

The hypothesis that CgA-derived peptides may be involved in mechanisms modulating motility was tested. Human colonic smooth muscles were studied using an organ bath technique. Acetic acid (AA) effects were characterized on spontaneous mechanical activities (SMA) and on responses to transmural nerve stimulation (NS). AA induced a significant decrease in tone and abolished SMA; this effect was insensitive to either TTX or L-NAME/apamin. The AA-induced inhibitory effects were significantly reduced in the presence of CgA4-16. This effect was insensitive to TTX or L-NAME/apamin. Furthermore, AA-induced effects were blocked in the presence of BAYK8644 and CgA4-16 together. The inhibitory effect of nifedipine was delayed in the presence of CgA4-16. NS induced a triphasic response. Only the excitatory components were reduced in the presence of AA. This effect was dose-related and remained unchanged in the presence of CgA4-16 alone, but was blocked in the presence of simultaneous administration of CgA4-16 and L-NAME/apamin. AA application induced inhibition of human colon motility in vitro. This effect may be mediated through an action on L-type calcium channels. CgA4-16 may display a protective role, which prevents the inhibition of motility due to AA to occur, by acting on both smooth muscle and afferent terminals.

Aerosol transfer of bladder urothelial and smooth muscle cells onto demucosalized colonic segments: a pilot study

PURPOSE

We developed a cell transfer technology for covering demucosalized colonic segments with bladder urothelium. This covering would be achieved through aerosol spraying of single cell suspension of bladder urothelial and smooth muscle cells with fibrin glue onto the demucosalized colonic segments.

MATERIALS AND METHODS

In 6 piglets (20 kg.) a 4 cm.2 area of bladder was excised. Single cell suspension of bladder urothelial and smooth muscle cells was prepared. A segment of detubularized sigmoid colon was isolated on its vascular pedicle and demucosalized. The single cell suspensions were combined with an equal volume of fibrin glue and sprayed over the raw submucosal surface of the sigmoid segment. The sigmoid segment was retubularized and sutured to the posterior peritoneum. Animals were sacrificed 4 weeks later, and the segment was submitted to histological and immunohistochemical analysis.

RESULTS

Sigmoid segments appeared grossly intact with no reduction in surface area. Hematoxylin and eosin architecture revealed an intact urothelial layer. Deep to this layer was a randomly aligned but distinctly segregated layer of smooth muscle cells. The urological new smooth muscle layer stained positive for calponin and the urothelial layer was cytokeratin-7 and uroplakin III positive.

CONCLUSIONS

Separation, cell suspension and aerosol delivery of bladder urothelial and smooth muscle cells in fibrin glue can successfully transfer these urological cell populations to a new host tissue commonly used in urological reconstruction. In vivo co-culture of bladder smooth muscle and urothelial cells results in coverage of a large area of demucosalized gut providing new potential for transfer and reconstitution of urologically functionally appropriate tissue to the bladder itself.

Gammadelta T cell receptor repertoire in blood and colonic mucosa of rhesus macaques

Although their precise roles are not well defined, gammadelta T lymphocytes are recognized as regular components of immune responses. These cells express a limited T cell receptor repertoire and they can be stimulated by soluble ligands without conventional processing and presentation by major histocompatibility antigens. Progress in this area has been limited by the substantial differences between murine and human gammadelta T cells and the lack of knowledge about these cells in nonhuman primates. We used molecular analysis of T cell receptor diversity to characterize gammadelta T cell populations from peripheral blood and colon of rhesus macaques (Macaca mulatta). The gammadelta T cell receptor diversity was limited and distinct for these tissue compartments, particularly in the TCRGV2 family. Furthermore, the TCRDV1 + subset of peripheral blood gammadelta T cells showed signs of progressive oligoclonalization as a function of age. Similar observations have been reported for human tissue samples and our results validate rhesus macaques as an appropriate animal model for studying primate gammadelta T cell populations.

Intestinal permeability in humans is increased after radiation therapy

PURPOSE

Irradiation inflicts acute injuries to the intestinal mucosa with rapid apoptosis induction and subsequent reduction in epithelial surface area. It may therefore be assumed that the intestinal barrier function is affected. The aim of this study was to compare the mucosal permeability in irradiated rectum and nonirradiated sigmoid colon from patients subjected to radiation therapy before surgical treatment for rectal cancer.

METHODS

Segments from sigmoid colon and rectum obtained from irradiated and nonirradiated patients were stripped from the serosa-muscle layer and mounted in Ussing diffusion chambers. The mucosa-to-serosa passage of the marker molecules 14C-mannitol, fluorescein isothiocyanate-dextran 4,400, and ovalbumin was followed for 120 minutes.

RESULTS

The permeability to the markers was size-dependent and increased linearly across time in all specimens. The passage of all markers was increased in irradiated rectum compared with nonirradiated sigmoid colon, whereas in specimens from nonirradiated patients there were no differences between rectum and sigmoid colon. Histologic signs of crypt and mucosal atrophy were found in the irradiated rectal specimens.

CONCLUSIONS

Early gastrointestinal complications after radiation therapy may be the result of mucosal atrophy in addition to mucosal damage, with a loss of barrier integrity.

Decreased interstitial cell of cajal volume in patients with slow-transit constipation

BACKGROUND & AIMS

The cause of slow-transit constipation is incompletely understood. Recent observations suggest a central role for interstitial cells of Cajal in the control of intestinal motility. The aim of this study was to determine the volume of interstitial cells of Cajal in the normal sigmoid colon and in the sigmoid colon from patients with slow transit constipation.

METHODS

Sigmoid colonic samples were stained with antibodies to protein gene product 9.5, c-Kit, and alpha-smooth muscle actin. Three-dimensional reconstruction of regions of interest was performed using consecutive images collected on a laser scanning confocal microscope and ANALYZE software.

RESULTS

Volume of interstitial cells of Cajal was significantly decreased in all layers of sigmoid colonic specimens from patients with slow-transit constipation compared with normal controls. Neuronal structures within the colonic circular smooth muscle layer were also decreased.

CONCLUSIONS

A decrease in the volume of interstitial cells of Cajal may play an important role in the pathophysiology of slow-transit constipation.

A bile acid-induced apoptosis assay for colon cancer risk and associated quality control studies

Bile acids are important in the etiology of colorectal cancer. Bile acids induce apoptosis in colonic goblet cells at concentrations comparable to those found in fecal water after high-fat meals. Preliminary evidence indicated that cells of the normal-appearing (nontumorous) portion of the colon epithelium of colon cancer patients are more resistant to bile salt-induced apoptosis than are cells from normal individuals. In the present study, 68 patients were examined, and biopsies were taken at 20 cm from the anal verge, cecum, and descending colon. The patients included 17 individuals with a history of colorectal cancer, 37 individuals with adenomas, and 14 individuals who were neoplasia free. The mean bile salt-induced apoptotic index among normal individuals was 57.6 +/- 3.47 (SE), which differed significantly (P < 0.05) from the mean value of 36.41 +/- 3.12 in individuals with a history of colon cancer. The correlation between independent observers was 0.89 (P < 0.001), indicating good interobserver reliability. Components of variance comparing interindividual versus intraindividual sources of variation suggested that site-to-site variability, both between regions of the colon and for adjacent biopsies, was larger than the interpatient variability for individuals with a history of neoplasia. Therefore, there was "patchiness" of the susceptibility of regions of the colon to bile acid-induced apoptosis in individuals with a history of neoplasia (a patchy field effect). There was no obvious correlation of low-apoptotic index regions with regions in which previous neoplasias had been found and removed. On the other hand, for normal, i.e., neoplasia-free, individuals, there was relatively less intraindividual variation compared to interindividual variation. Our assay shows an association between resistance to bile acid-induced apoptosis, measured at 20 cm from the anal verge, and colon cancer risk. Thus, this assay may prove useful as a biomarker of colon cancer risk.

Geographic variations in eosinophil concentration in normal colonic mucosa

We reviewed 256 mucosal biopsy specimens from the descending and sigmoid colon obtained from surgical pathology departments in several areas of the United States. Only specimens of normal colonic mucosa were included, i.e., no specimens with acute or chronic colitis or adenomatous change, or in which eosinophils invaded the crypts or muscularis mucosae. The mean number of eosinophils per intercryptal space was highest in the southern United States, and there was a 35-fold difference between the mean eosinophil concentrations of patients in New Orleans and Boston. The reason for geographic variation is unknown, but it might be related to allergens in the environment or diet. Normal variations in mucosal eosinophil concentrations should be measured within a specific region before evaluating colonic biopsy specimens for eosinophilia.

Quantitative analysis of MUC2 synthesis in ulcerative colitis

MUC2 is the predominant mucin in the human colon responsible for the protective mucus layer. We developed methods to quantify MUC2 biosynthesis, which were used to study the regulation of MUC2 expression in the colon of normal individuals and of patients with ulcerative colitis. Colonic biopsies were metabolically labeled, and biosynthesis of MUC2 precursor was quantified using SDS-PAGE. Total MUC2 and MUC2 mRNA were quantified using blotting techniques. MUC2 precursor biosynthesis and total MUC2 levels were significantly decreased in ulcerative colitis patients with active inflammation compared to controls. In contrast, both these parameters returned to control values during remission of the inflammation, demonstrating that colonic biosynthesis and total amounts of MUC2 vary according to the activity of the disease. However, MUC2 mRNA levels were similar in all patients and independent of disease activity, indicating that these variations in MUC2 synthesis are post-transcriptionally regulated.

Effect of free glutamine and alanyl-glutamine dipeptide on mucosal proliferation of the human ileum and colon

BACKGROUND/AIMS

Glutamine (Gln) is considered a trophic factor for small intestinal epithelia, which is important during severe illness. Its use in parenteral nutrition is precluded by its instability, a problem that may be overcome by use of the stable dipeptide L-alanyl-L-glutamine (Ala-Gln). The hypothesis was tested that Gln or Ala-Gln may stimulate cell proliferation not only in the ileum but also in the proximal and distal colon and, thus, may contribute to the gut barrier function.

METHODS

Biopsy samples from the normal human ileum, proximal colon, and rectosigmoid were incubated for 4 hours with Gln (2 mmol/L), Ala-Gln (2 mmol/L), and saline (control). Cells in S phase were labeled with bromodeoxyuridine. In longitudinal crypt sections labeled and quiescent cells were counted.

RESULTS

Gln as well as Ala-Gln stimulated crypt cell proliferation in the ileum, proximal colon, and rectosigmoid colon. In ileal specimens, labeling was greater in the entire crypt, whereas in both colonic regions, the trophic effect was confined to the basal crypt compartments.

CONCLUSIONS

Gln and Ala-Gln have trophic effects not only in the ileum, but also in the proximal and distal colon. This could be important during parenteral nutrition when mucosal atrophy may weaken the gut barrier.

Antagonistic effects of deoxycholic acid and butyrate on epithelial cell proliferation in the proximal and distal human colon

Colon cancer is a major malignant disease in Western countries where--for unknown reasons--it occurs predominantly in the distal colon. Fecal secondary bile acids are an important risk factor whereas butyrate may be a protective agent. In this in-vitro study biopsies from the normal ascending and sigmoid colon of 24 subjects were incubated with 5 microM DCA (proximal vs. sigmoid colon) or DCA and DCA plus 10 mM butyrate (DCA vs. DCA/BUT, only sigmoid colon) and cell proliferation measured by bromodeoxyuridine immunohistochemistry. Whole crypt labeling index (LI) after DCA-incubation was similar in the ascending (15.4%) and sigmoid colon (15.4%) indicating an equal mucosal response of the two colonic subsites to DCA. Compared to DCA/BUT, incubation with DCA alone resulted in a significantly higher LI for the whole crypt (16.8 vs. 11.4%, p < 0.01) and for the upper 40% of the crypt (4.5 vs. 0.8%, p < 0.01). This may indicate a butyrate-related decrease in the susceptibility for colon cancer. Since luminal concentrations of DCA and butyrate are influenced by dietary interventions the findings of this study may be of particular interest with regard to colon cancer development and prevention.

A technique for segmental rectal and colonic perfusion in humans

To enable a better characterization of pathophysiologic processes in colon and rectum, we have developed a perfusion technique for collection of soluble substances and cells from standardized intestinal segments. A tube with balloons attached to its outer wall was endoscopically introduced into the rectum and sigmoid colon, and its position ascertained fluoroscopically. The balloons delimited two segments, one in the sigmoid colon and one in the rectum. The segments were simultaneously perfused by a buffer at 37 degrees C. After a 30-min rinsing period, perfusate and cells were collected at 20-min intervals. Of 51 attempted perfusions, 45 were successfully completed. Recovered volumes equaled those infused. Leakage from the proximal intestine to the segments was negligible. In 18 healthy volunteers, the mean perfusate concentration from the rectal segment was 57.5 (27.5-120.2) mg/L for albumin, 1.3 (1.0-1.7) micrograms/L for eosinophil cationic protein, 5.1 (2.8-9.5) ng/L for prostaglandin E2, and 61.7 (41.7-89.1) micrograms/L for hyaluronan, and all values were lower in the sigmoid segment. Steady state conditions were achieved from the second perfusion period. The perfusate contained 4-80 x 10(4) cells, more than 95% of which were epithelial cells. The technique is safe, has a good subject compliance, and seems to be a valuable tool in investigations on quantitative release of soluble substances and cells in, e.g., colorectal inflammation.

Pattern of epithelial cell proliferation in colorectal mucosa of normal subjects and of patients with adenomatous polyps or cancer of the large bowel

Microautoradiography has been largely used to characterize the proliferative activity of colorectal mucosa. We used this technique in a large series of patients with polyps or cancer of the large bowel and in normal controls with the following objectives: (a) to define the normal pattern of cell replication in different tracts of the large bowel; (b) to compare the proliferative activity of colonic crypts in patients with colorectal cancer or polyps with that of controls; (c) to evaluate replicative activity of colorectal mucosa in the close vicinity and at distance from a neoplastic mass. Specimens of colorectal mucosa were taken during endoscopy (controls and polyps) or at surgery (cancer). During histological examination each intestinal hemicrypt was divided into five equal longitudinal compartments from the base to the surface and the labeled cells in each compartment were counted. In controls, total labeling index (ratio of labeled to total cells) and labeling index per crypt compartment showed only minor differences between the various large bowel tracts. Total labeling index tended to be higher in patients with polyps or cancer than in controls (13.5 +/- 0.4 and 12.5 +/- 0.4, respectively, versus 11.3 +/- 0.5). Labeling index per crypt compartment in the most superficial portions of the crypt (compartments 3 to 5) was significantly higher in the two groups of patients with tumors than in controls. This was particularly evident in the fifth compartment (the most superficial), in which labeled cells were observed in 15.8% (three subjects out of 19) of controls but in 71% (15 out of 21) and 87.5% (14 out of 16) of polyp and cancer patients, respectively. In patients with colorectal cancer there were not significant differences of cell proliferation between mucosal samples taken at various distances from the tumor margin; however, increased cell replication, especially in the most superficial portions of the crypt, has been observed. In conclusion, a significant upwards expansion of the proliferative zone of intestinal glands has been observed in patients with either polyps or cancer of the large bowel. In particular, labeling of the fifth compartment seems to possess the highest discriminatory power between subjects with or without intestinal neoplasms. Hyperproliferation of the entire colonic mucosa seems to be a common feature in patients with colorectal cancer.

The crypt cycle. Crypt and villus production in the adult intestinal epithelium

We propose a model for the growth of individual crypts that is able to account for the observed changes in the number of cells in crypts under normal conditions, after irradiation, and after 30% resection. Parameter values for this model are estimated both for mouse and man, and detailed predictions of crypt growth rates are made. This model does not predict a steady-state crypt size; rather it suggests that crypts grow until they bifurcate. We therefore propose a crypt cycle (analogous to the cell cycle) and present evidence that most if not all crypts in the adult mouse are cycling asynchronously and independently. This evidence consists of four experiments that indicate that branching crypts are randomly distributed over the intestinal epithelium, that the plane of bifurcation of branching crypts is randomly oriented with respect to the villus base, and that the size distribution of crypts is consistent with an expanding crypt population. We also report for the first time evidence of villus production in the adult mouse intestinal epithelium. We conclude that the crypt and villus populations in the adult mouse are not in a steady state.

Elastic fibers in musculature of rectosigmoid colon: normal findings in children and changes in Hirschsprung's disease--a preliminary report

In order to determine the possible implication of elastin in spasticity of the aganglionic segment in Hirschsprung's disease the elastic fibers in the colon at rectosigmoid level were studied in seven surgical specimens of aganglionic bowel and in seven normal controls. Elastic fibers in both the muscle layers of normal bowel are thin, tend to be straight, and follow the line of muscle fasciculi. In aganglionic bowel, however, the fibers are more numerous and thicker in both layers, and in the longitudinal layer they are laid down in spirals. The total elastin content is increased by approximately 100% as compared with controls. These structural and quantitative changes in the elastin may contribute both to the spasticity and to the increased elasticity of the aganglionic segment.

Glucagon-, glicentin-, and pancreatic polypeptide-like immunoreativities in rectal carcinoids and related colorectal cells

Three nonargentaffin rectal carcinoids have been investigated immunohistochemically. In one case most tumor cells reacted with antiglucagon sera as well as with antiglicentin, antibovine pancreatic polypeptide (BPP), and antihuman pancreatic polypeptide (HPP) sera; they were identified ultrastructurally as L cells. Another case showed glucagon-, glicentin-, and BPP-immunoreactive cells but lacked HPP immunoreactivity. In the third case glucagon- and glicentin-immunoreactive cells were well represented, while PP immunoreactivities were scarce. Parallel investigations of human rectal and sigmoid mucosa showed numerous cells reacting with glucagon, glicentin, and BPP antisera, most of which lacked HPP immunoreactivity. Cells reacting with glucagon and glicentin antisera, while lacking PP immunoreactivities, were also found. Thus, both tumor and nontumor cells produce glucagonlike immunoreactive (GLI) peptides--one of which may be glicentin or a related molecule--as well as PP-related sequences, although differing histochemically and ultrastructurally from glucagon or PP cells of the human pancreas. It is concluded that nonargentaffin rectal carcinoids are histogenetically linked to nonargentaffin endocrine cells of the human rectum.

Relationship between functional and histologic appearances of developing ganglion cells in the guinea pig rectum

Time dated fetal guinea-pigs between 47 and 67 days gestation were studied for segmental propulsive activity in the rectosigmoid under fluoroscopy. Large bowel from the sacrificed fetus was studied histologically to determine distribution and morphology of ganglion cells. Contractions were first observed on day 54 and these became more frequent and vigorous after day 63. Between 47-53 days gestation circular muscle is thin and neurons consists of cluster of neuroblastic cells. Near the end of gestation the neurons arrange themselves into discrete groups and have an appearance like mature ganglion cells.

A morphologic study of the submucosa of the large intestine

The morphologic structure of human, rat and mouse submucosa is similar. The strength, natural tension and extensibility of the submucosa can be readily interpreted form the physical properties of collagen and its structural arrangement as a pliable honeycomb. The perforations allow blood and lymph vessels to reach the mucosa.

Histologic appearance of the intestinal urinary conduit

The histology of intestinal urinary conduits (8 ileal and 2 sigmoid) in place for 10 months to 10 years was studied in 10 patients between 20 and 65 years old. It is concluded that the ileum and the large intestine do not undergo adaptive metaplastic transformation. The only changes observed are related to a condition of chronic irritation to which the response is a chronic inflammatory reaction. Structures proving to be the most resistant were the cells of Paneth. The latter were not damaged in appearance and number as compared to normal, even when the conduit was in place for 10 years.

[Finding of ganglion cells in the mucosa of the colon, sigmoid flexure, and rectum (author's transl)]

The ectopic position of the ganglion cells of Meissner's plexus in the basal and central portions of the mucosa in the colon descendens and sigmoid flexure, as they were found by Stöhr in humans, by Ohkubo in monkeys, and by Meier-Ruge in neuronal colon dysplasia, can be considered a relatively frequent finding. The present authors also observed the cells in human biopsy material. The same position in the rectal mucosa, frequently seen in Morbus Down, seems to be a rare occurrence. The clinical relevance of an ectopic position of ganglion cells is not yet known.

Histochemistry of the colonic epithelial mucins in normal subjects and in patients with ulcerative colitis. A qualitative and histophotometric investigation

Images

An electron microscopic study of epithelium of normal human sigmoid colonic mucosa

Images