Inflammatory bowel diseases (IBD), such as Crohn's disease and ulcerative colitis, are chronic inflammatory conditions affecting the gastrointestinal tract with variable presentations and disease courses. The cause of IBD is unknown, but it is hypothesized that individuals with a genetic predisposition to disease develop an aberrant immune response to environmental triggers. Evidence suggests that microbiota residing in the gastrointestinal tract play an important role in the development and perpetuation of the disease. In this review, we discuss the role of microbes in the development of a healthy gut, their role in the development of diseases in general, and their role in the development of IBD. Advances in molecular technologies and bioinformatics will continue to further our insight into the structure of the microbial community, the function of the microbial community as a whole, and the interaction of this community with the host immune system. The latter two are crucial to understanding the role of microbes in IBD. The field has advanced significantly in recent years, and the future is very promising as we begin to elucidate the microbial basis of IBD.
Colitis, Ulcerative ; Computational Biology ; Crohn Disease ; Gastrointestinal Tract ; Genetic Predisposition to Disease ; Immune System ; Inflammatory Bowel Diseases* ; Microbiota

OBJECTIVE: Considering the different prevalence rates of diseases such as asthma and chronic obstructive pulmonary disease in Asians relative to other races, Koreans may have unique airway structure and lung function. This study aimed to investigate unique features of airway structure and lung function based on quantitative computed tomography (QCT)-imaging metrics in the Korean Asian population (Koreans) as compared with the White American population (Whites). MATERIALS AND METHODS: QCT data of healthy non-smokers (223 Koreans vs. 70 Whites) were collected, including QCT structural variables of wall thickness (WT) and hydraulic diameter (Dh) and functional variables of air volume, total air volume change in the lung (ΔVair), percent emphysema-like lung (Emph%), and percent functional small airway disease-like lung (fSAD%). Mann-Whitney U tests were performed to compare the two groups. RESULTS: As compared with Whites, Koreans had smaller volume at inspiration, ΔVair between inspiration and expiration (p < 0.001), and Emph% at inspiration (p < 0.001). Especially, Korean females had a decrease of ΔVair in the lower lobes (p < 0.001), associated with fSAD% at the lower lobes (p < 0.05). In addition, Koreans had smaller Dh and WT of the trachea (both, p < 0.05), correlated with the forced expiratory volume in 1 second (R = 0.49, 0.39; all p < 0.001) and forced vital capacity (R = 0.55, 0.45; all p < 0.001). CONCLUSION: Koreans had unique features of airway structure and lung function as compared with Whites, and the difference was clearer in female individuals. Discriminating structural and functional features between Koreans and Whites enables exploration of inter-racial differences of pulmonary disease in terms of severity, distribution, and phenotype.
Asian Continental Ancestry Group ; Asthma ; Continental Population Groups ; Female ; Forced Expiratory Volume ; Humans ; Lung ; Lung Diseases ; Phenotype ; Prevalence ; Pulmonary Disease, Chronic Obstructive ; Thorax ; Trachea ; Vital Capacity