Importance of investigation of inflammatory bowel disease in China

Inflammatory bowel disease: beyond the boundaries of the bowel

Dysregulated inflammation in the gut, designated clinically as inflammatory bowel disease (IBD), is manifested by the prototypic phenotypes of an Arthus-like reaction restricted to the mucosa of the colon, as in ulcerative colitis, or a transmural granulomatous reaction, as in Crohn's disease, or an indeterminate form of the two polar types. That the inflammation of IBD can trespass the boundaries of the bowel has long been known, with articular, ophthalmologic, cutaneous, hepatobiliary or other complications/associations - some autoimmune and others not - affecting significant numbers of patients with IBD. Also notable is the frequency of diagnosis of IBD-type diseases on a background of systemic, (mostly myelo-hematological) disorders, associated with alterations of either (or both) innate or adaptive arms of the immune response. Finally, cases of IBD are reported to occur as an adverse effect of TNF inhibitors. Bone marrow transplant has been proven to be the only curative measure for some of the above cases. Thus, in effect, the IBDs should now be regarded as a systemic, rather than bowel-localized, disease. Genome-wide association studies have been informative in consolidating the view of three phenotypes of IBD (ulcerative colitis, Crohn's disease and mixed) and, notably, are revealing that the onset of IBD can be linked to polymorphisms in regulatory miRNAs, or to nucleotide sequences coding for regulatory lymphokines and/or their receptors. At the effector level, we emphasize the major role of the Th17/IL-23 axis in dictating the perpetuation of intestinal inflammation, augmented by a failure of physiological control by regulatory T-cells. In conclusion, there is a central genesis of the defects underlying IBD, which therefore, in our opinion, is best accommodated by the concept of IBD as more of a syndrome than an autonomous disease. This altered mindset should upgrade our knowledge of IBD, influence its medical care and provide a platform for further advances.

Epidemiology of lower gastrointestinal bleeding in China: single-center series and systematic analysis of Chinese literature with 53,951 patients

OBJECTIVES

The epidemiology of lower gastrointestinal bleeding (LGIB) in Western populations has been reported; however, there are scant Asian reports. The aim of the present study was to determine the etiology of LGIB in a Chinese population by reporting a retrospective case series and a systematic analysis of Chinese literature.

METHODS

A large colonoscopy database in a tertiary endoscopic center was searched to identify all patients with the indication of LGIB. The data, including patients' sex, age, endoscopic and pathological findings, were collected and analyzed. A comprehensive database search of the Chinese literature was carried out to obtain all relevant studies.

RESULTS

In our series, a total of 720 patients with LGIB were included. There were 425 males and 295 females with a median age of 50 years, the most common etiologies of LGIB were inflammatory bowel disease (IBD; 30.2%), polyps (23.4%) and cancer (10.7%). In 30.2% of all the patients, no obvious causes were identified. A systematic analysis of Chinese literature found an additional 160 studies providing relevant data in 53,951 patients. Overall, colorectal cancer (24.4%), colorectal polyps (24.1%), colitis (16.8%), anorectal disease (9.8%) and IBD (9.5%) were the most common etiologies of LGIB. The main etiologies were different between adults, the elderly and children.

CONCLUSION

The study shows colorectal cancer, colorectal polyps, colitis, anorectal disease and IBD were the most common etiologies of LGIB in the Chinese adult and elderly population, whereas colorectal polyps, chronic colitis and intussusception were the main causes of LGIB in Chinese children. Whereas diverticulum, the most common cause of LGIB in Western populations, is uncommon in China.