Characteristics Analysis Of Small Bowel Crohn’s Disease And Roles Of Heparan Sulfate Proteoglycan In Crohn’s Disease Diagnosis

Background and aimsCrohn’s disease (CD) is a major type of inflammatory bowel disease (IBD), which is a chronic transmural inflammation that of the alimentary tract from mouth to anus and is associated with many extraintestinal features. Although the incidence and prevalence of ulcerative colitis and Crohn’s disease are beginning to stabilize in high-incidence areas such as northern Europe and North America, they continue to rise in low-incidence areas such as southern Europe, Asia, and much of the developing world. Etiology and pathogenesis of the disease remains unclear, and it was usually contributed to complex and multifactorial pathologic processes.Small bowel involvement merely, with a preference for the distal ileum, can be found in 30-40% of CD cases. However, elucidation of the cause of small bowel disease is usually an extraordinarily difficult job because of the length and arrangement of this section of the bowel and because of the lack of diagnostic tools which can directly visualize the whole small bowel. The routine diagnostic methods available, such as radiological techniques and abdominal ultrasound, have been insensitive and inaccurate. All of these limitations had caused apparente delay of CD diagnosis and treatment. Since the development and application of two promising diagnostic modalities early in the 21st century, capsule endoscopy (CE) and double balloon enteroscopy (DBE), the diagnostic capability for detecting CD lesions in small bowel has been greatly improved. To date, however, a few studies have focused on the clinical and endoscopic features and the practical influence of the small bowel lesions detected by CE and DBE.For no pathognomonic hallmark and definitive criteria, the diagnosises of CD for most patients are usually based on a collection of clinical symptoms, endoscopic, radiologic, laboratory and histopathologic findings. These non-specific symptoms and findings may overlap masses of disease, such as irritable bowel syndrome, infection, NSAID enteritis, malignancy, etc. and cause practical judgment and decision difficultly. Since tuberculosis has also staged a comeback and its epidemic in the world is serious, such difficulties are more prominent between CD and intestinal tuberculosis (ITB). Though becoming increasingly recognized, their differential diagnosises still depend largely upon empirical treatment and follow-up procedure. The morbidity and mortality resulting from a delayed diagnosis or misdiagnosis is considerably high.There is a growing view that, the impaired barrier and intestinal disease are closely linked and well interactions. The integrity defect and mucosal immune abnormal can be both triggers and results of bowel disorders. Previous research showed that increased intestinal permeability is a consistent finding in patients with both remission and active Crohn’s diease. Such gut permeability altered often represents a dysregulated of mucosal junctional proteins and their respective mRNAs. Due to the less and localed lesion, and arteritis obliterans at the base, however, intestinal permeability is normal or no significant change in patients with active tuberculosis. Therefore, the study and comparison of intestinal barrier functions may lead to a better understanding of the pathogenesis and difference between CD and ITB.Heparan sulfate proteoglycans (HSPG) are widely distributed on the surface of vertebrate cells. They have diverse biological effects on cell proliferation, adhesion, signal transduction, immune response and other physiological and pathological processes. It has been well demonstrated that HSPG is implicated with intestinal barrier and pathogenesis, and its predominance, syndecan-1 (SYD1), plays essential roles in epithelial-junction formation and maintenance. Heparanase (HPA) is an endo-beta-D-glucuronidase capable of cleaving heparan sulfate (HS) side chains at a limited number of sites, and its activity correlated with the metastatic potential of tumor-derived cells, neovascularization, inflammation and autoimmunity. Our previous study found that SYD1 might be used as a marker for IBD monitoring and the colonic expression of SYD1 protein in colitis model mice is correlated with the severity of colitis. Matti Waterman found that HPA was upregulation by colonic epithelium in IBD and un-fractionated as well as low molecular weight heparin (enoxaparin), which exhibit a strong inhibitory activity towards HPA, have proven efficacious in CD and ulcerative colitis patients. Conversely, when mycobacterium tuberculosis adheres to epithelial cells, it does not affect much of the tight junctions or SYD1. The invasion of mycobacterium tuberculosis requires HSPG’s assistance while HPA treatment in vitro showed obviously inhibitation for mycobacterial adherence. All of these indicate that certain differences, which still need further experimental confirmation, might be showed on the expressions of SYD1 and HPA between CD and ITB.Based on the above research background, our study, firstly, was to approach clinical and endoscopic features of CD of small bowel, then to evaluate the diagnostic efficiency of jejunoileal endoscopy (including CE and DBE) in CD, and finally to study on whether SYD1 and HPA could help in differential diagnosis between CD and ITB.Materials and Methods1.Diagnostic criteria:The Rome III criteria (Gastroenterology,2006) was designed as diagnostic criteria for FBD (as normal control). The diagnosis of confirmed TB was based on affected tissues with one or more of the following:(1) histological evidence of granulomas with caseating necrosis, (2) demonstration of acid-fast bacilli (AFB) by Ziehl-Neelsen (ZN) stain, or (3) culture of Mycobacterium tuberculosis. Patients in whom the diagnosis was suspected though unconfirmed by histology or microbiology were regarded as having presumed intestinal TB, if they were treated successfully with anti-tuberculous chemotherapy. CD Diagnosis was based on Chinese Consensus on Diagnosis and Treatment Standard of Inflammatory Bowel Disease (Ji’nan,2007) and CD activity index is quantified by Harvey-Bradshaw index.2. Subjects and methods:2.1 Hospitalized patients with CD, who underwent DBE (EN-450P5/20, Fujinon Inc, Saitama, Japan) and CE (OMOM, Jinshan Science and Technology Group, Chongqing, China) in Nanfang hospital from January 2004 to December 2008, were included. Clinical data, imagine, endoscopy and pathology records were reviewed and retrospectively analyzed.2.2 Our study was approved by the hospital ethics committee. A group of 43 patients with FBD (as control, n=10), ITB (n=12) and CD (remission n=6, moderate active n=6 and severe active n=9) were included. All were hospitalized patients admitted to Nanfang hospital from March 2008 to August 2008. Paraffin biopsies and serum samples were studied by immunohistochemisty and ELISA detection of both SYD1 and HP A.2.3 Statistical analysis was performed with SPSS 13.0 software. Descriptive statistics were calculated with means and standard deviation. The enumeration data were calculated with sample number and percentage and compared with theχ2 test. The inner relationships between groups and detective value were discussed with Spearman Correlation or Partial Correlation. Kruskal-Wallis test or Mann-Whitney test was applied to define differences of disease severity and staining intensity among groups included in the study. Association significant when P<0.05 is considered.Results1. Fifty-four patients, most of which were male, had been enrolled in our series, with the average onset age of 28.9 years and the mean duration of 35.6 months. The main symptoms were abdominal pain, diarrhea, malnutrition, anemia, melena/hematochezia and fever, with obstruction, fistula formation and massive bleeding as common complications. The primary lesions under endoscopy were erosions/ulcerations, stenosis, nodular hyperplasia. Lesions, which performed as segmental and skipping, had involved 48.6% of jejunum,77.1% of ileum (excepted terminal ileum), and 62.9% of terminal ileum and ileocaecal valve.2. The main indications for JIE in our series were suspected CD (42.6%) and obscure gastrointestinal bleeding (25.9%). JIE was obviously superior to barium imaging. The yield of JIE (92.6%) was significantly higher when compared to ileocolonscopy (75.9%) (P=0.017), and the specific endoscopic features supplied with JIE, such as segmental distribution and lumens change, were much more. JIE can significantly improve the diagnostic efficiency, but would rather give priority to offer a guide and raise suspected diagnosis for CD.3. SYD1 intensity of immunohistochemical staining of CD specimens were significantly lower than FBD and ITB specimens (P=0.001). Proportions of HPA positively staining of CD specimens was obviously higher than other groups. Significant differences of SYD1 and HPA serumal concentrations were found, not only between CD and ITB, but at the different stages of CD, and such expressions and contrasts were less affected by severity of tissue or systemic inflammation.Conclusion1. Small bowel Crohn’s disease could cause diversity of clinical manifestations. Though some showed certain characteristics, most lesions located in small bowel were non-specific. It is still hard to definitely diagnose the small-bowel Crohn’s disease and it needs a combined course that integrates the endoscopic information with all valuable clinical evidences and clues.2. JIE is useful to detect CD lesions located in jejunum and ileum and to evaluate involvement and severity. Reasonable JIE procedure, and the adequate integration with JIE results and routine imaging, gastroendoscopy, clinical data, etc., would further enhance JIE’s effectiveness and clinical impact in diagnosis, therapy and surveillance for CD.3. SYD1 and HPA detections in tissue and surum might be helpful for differential diagnosis between CD and ITB, and evaluation of CD severity.