Bao-Hua Liu

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

Background and aimsSlow 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 methodsTwelve 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.ResultsICC 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.ConclusionsSimilar 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.

Expression of c-kit messenger ribonucleic acid and c-kit protein in sigmoid colon of patients with slow transit constipation.

Background and aimsThe c-kit protooncogene receptor and its ligand stem cell factor regulate the proliferation and survival of germ cells as well as interstitial cells of Cajal (ICCs). Decreased numbers of ICCs and defects in its networks have been reported in the colon of patients with slow transit constipation (STC). However, little information about the c-kit messenger ribonucleic acid (mRNA) and protein expression in the constipated colon is available. The aim of this study was to determine whether the expression of c-kit mRNA and c-kit protein declined in the colon in STC.Patients and methodsThe sigmoid colonic samples from 12 patients with STC and from eight age-matched patients with non-obstructed colorectal cancer were used for this study. Expression of c-kit mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), and expression of c-kit protein was detected by Western blot analysis.ResultsDecreased expression of c-kit mRNA was demonstrated in the STC group compared with the control group. The ratio of c-kit and β-actin was 1.26±0.32 in controls and 1.17±0.41 in the STC group (U=0.500, P=0.029). c-kit protein expression significantly declined in the STC group. The mean value of optical density was 162.97±5.43 in the control group and 96.64±8.80 in the STC group (U=0.000, P=0.021).ConclusionsThe data indicate that the expression of c-kit mRNA and c-kit protein significantly decreased in the colon of STC, suggesting that the c-kit signal pathway may play an important role in ICC reduction in STC.

Identification of IMPDH2 as a tumor-associated antigen in colorectal cancer using immunoproteomics analysis.

Background and aimsSera from cancer patients contain tumor-specific autoantibodies directly against antigenic proteins. The identification of tumor autoantigens may have utility in cancer diagnosis, prognosis, and therapy. In this study, we used immunoproteomics analysis to identify tumor proteins that elicit humoral response in colorectal cancer (CRC).Materials and methodsThe CRC cell line HCT116 was used as a source of proteins for two-dimensional polyacrylamide gel electrophoresis and subsequent Western blot analysis in which individual serum from patients with CRC was analyzed for autoantibodies. Proteins that specifically react with sera from cancer patients were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometric analysis. In addition, the selected protein expression in tumor tissues collected from 40 patients with CRC were assessed by immunohistochemistry.ResultsAn autoantibody against inosine monophosphate dehydrogenase II (IMPDH2) identified by mass spectrometry was detected in eight out of 25 patients with CRC. However, none of the 15 healthy controls demonstrated autoantibody to IMPDH2.The expression of IMPDH2 in tumor tissue was significantly higher in patients with CRC than that in healthy subjects.ConclusionsThe result confirmed that the immunoproteomics analysis holds considerable promise for the discovery of tumor-associated antigens. IMPDH2 may be a protein biomarker and novel therapeutic target in CRC.

c-Rel is a transcriptional repressor of EPHB2 in colorectal cancer

The receptor tyrosine kinase EPHB2 has recently been identified as a TCF4 transcriptional target that controls the intestinal epithelial architecture through repulsive interactions with Ephrin‐B ligands. Many reports have demonstrated that most human colorectal cancers lose EPHB2 expression despite constitutive Wnt activation. Therefore, we investigated the mechanisms that cause EPHB2 down‐regulation in colorectal cancer. In this study, we demonstrate that DNA hypermethylation was not responsible for the frequent loss of EPHB2 expression in colorectal cancer. Cloning and functional characterization of the EPHB2 gene 5′‐flanking region revealed a potential negative regulatory element in the distal regulatory region. In vitro electrophoretic gel mobility shift and in vivo chromatin immunoprecipitation assays demonstrated that c‐Rel directly binds to the putative element. Inhibiting c‐Rel activity or knocking down c‐Rel expression by RNA interference in colon cancer cells was sufficient to induce EPHB2 expression. Furthermore, transient transfection assays demonstrated that c‐Rel over‐expression repressed endogenous EPHB2 expression in colon cancer cells. We demonstrate for the first time that c‐Rel acts as a transcriptional repressor of EPHB2 and plays an active role in EPHB2 down‐regulation in colorectal cancers. Copyright

Role of pelvicography and colpocystodefecography in diagnosis of outlet obstructive constipation

AimsThe aim was to research the changes in pelvic floor morphology and corresponding visceras in patients with outlet obstructive constipation (OOC).Patients and methodsThirty-eight patients with OOC and 12 healthy volunteers were enrolled in this study. With simultaneous pelvicography and colpocystodefecography (PCCD), including pelvicography, vaginal opacification, voiding cystography and defecography, pelvic floor morphology was observed and the anorectal angle, the level of the perineum, peritoneum and bladder were measured.ResultsThirty-seven cases of internal rectal prolapse (IRP), 5 cases of rectocele (RC) and 5 cases of spastic pelvic floor syndrome SPFS were diagnosed by PCCD. 12 IRP, 4 RC and 1 SPFS were detected by common physical examination. All of these were confirmed by PCCD. Moreover, PCCD found 9 pelvic floor hernia or peritoneoceles, 6 cystoceles, 3 descending perineum syndromes and 10 uterine prolapses. Compared with controls, OOC patients had a significantly large anorectal angle during defecation, abnormal descending of the perineum at rest and during defecation, and a deep pouch of Douglas during defecation. Some patients with urinary system symptoms may have had an abnormal descent of the bladder during rest and defecation.ConclusionSimultaneous PCCD has a higher positive ratio than the common physical examination in diagnosing IRP and RC, and provides information for the diagnosis of pelvic floor hernia or peritoneocele, cystocele or uterine prolapse. PCCD is helpful in the selection of a proper surgical procedure.

Transvaginal local excision of rectal carcinoma.

PURPOSEnTo recommend a new approach-transvaginal local excision of early rectal cancers-and report the results of the approach applied by dedicated surgeons at a specialized colorectal unit during a 10-year period.nnnMETHODSnThe surgical outcome of 18 patients undergoing transvaginal local resection between January 1991 and August 2001 was reviewed. Patients were identified according to the consultants personal records and cross-referenced with the operating room logs. Data were collected retrospectively, and follow-up was performed on all patients.nnnRESULTSnA total of 18 patients underwent 18 procedures during the study period. Follow-up ranged from 2 months to 104 months. There were no treatment-related complications. Two patients suffered from recurrences at a median follow-up time of 35.7 months, but they underwent subsequent surgical treatment: APR (one) and LAR (one). No evidence of disease was found during a median follow-up of 20 months (12 and 28 months). No one died.nnnCONCLUSIONSnTransvaginal local excision is an alternative and feasible technique with low rates of death and complications for the treatment of rectal cancer in strictly selected cases.

Identification of differential proteins in colorectal cancer cells treated with caffeic acid phenethyl ester.

AIMnTo investigate the molecular mechanisms of the anti-cancer activity of caffeic acid phenethyl ester (CAPE).nnnMETHODSnProtein profiles of human colorectal cancer SW480 cells treated with or without CAPE were analysed using a two-dimensional (2D) electrophoresis gel-based proteomics approach. After electrophoresis, the gels were stained with Coomassie brilliant blue R-250. Digital images were taken with a GS-800 Calibrated Densitometer, and image analysis was performed using PDQuest 2-D Analysis software. The altered proteins following CAPE treatment were further identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry following a database search. The identified proteins were validated by Western blot and immunofluorescence assay.nnnRESULTSnCAPE induced human colorectal cancer cell apoptosis. Four up-regulated proteins and seven down-regulated proteins in colorectal cancer cells treated with CAPE were found. The identified down-regulated proteins in CAPE-treated colorectal cancer cells were Triosephosphate Isomerase (Tim), Proteasome subunit alpha 4 (PSMA4) protein, Guanine nucleotide binding protein beta, Phosphoserine aminotransferase 1 (PSAT1), PSMA1, Myosin XVIIIB and Tryptophanyl-tRNA synthetase. Notably, CAPE treatment led to the down-regulation of PSAT1 and PSMA1, two proteins that have been implicated in tumorigenesis. The identified up-regulated proteins were Annexin A4, glyceraldehyde-3-phosphate dehydrogenase, Glucosamine-6-phosphate deaminase 1 (GNPDA1), and Glutathione peroxidase (GPX-1). Based on high match scores and potential role in cell growth control, PSMA1, PSAT1, GNPDA1 and GPX-1 were further validated by Western blotting and immunofluorescence assay. PSMA1 and PSAT1 were down-regulated, while GNPDA1 and GPX-1 were up-regulated in CAPE-treated colorectal cancer cells.nnnCONCLUSIONnThese differentiated proteins in colorectal cancer cells following CAPE treatment, may be potential molecular targets of CAPE and involved in the anti-cancer effect of CAPE.

Outcome of transvaginal excision of large rectal adenomas

PurposeThe purpose is to recommend a new approach—transvaginal excision—for large rectal adenomas and audit its results after being performed by dedicated surgeons at a specialized colorectal unit.MethodsThe surgical outcome of 11 patients undergoing transvaginal excision between July 1995 and March 2000 was reviewed. Data were collected retrospectively and no patients were lost to follow-up.ResultsEleven patients underwent the procedure during the study period. Follow-up ranged from 7 to 75xa0months. There were complications in two patients. One had urinary retention, the other developed a rectal stenosis, which was resolved with multiple balloon dilatations. There was only one recurrence detected. None of the patients died.ConclusionsTransvaginal local excision is an alternative and feasible technique for the treatment of selected large sessile rectal adenomas that carries low mortality and complication rates.