京都大学 / 新制・課程博士 / 博士(医学) / 甲第23806号 / 医博第4852号 / 新制||医||1058(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 森信 暁雄, 教授 上野 英樹, 教授 椛島 健治 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

<p>Currently, there is no effective cure for Inflammatory Bowel Disease (IBD), medications are aimed solely at alleviating symptoms and not curative. Great scientific efforts have been aimed at elucidating the mechanisms underlying the pathogenesis of IBD. Macrophages—antigen presenting cells—play a chief role in the pathophysiology of IBD. It has been proposed that CD36 receptor present on the surface of macrophages, may play a role in the inflamed intestine. CD36-expressing macrophages have been implicated in a variety of human diseases; however the role of CD36+ macrophages in the intestine has been limited. The aim of this study was to decipher whether or not CD36+ F4/80+ macrophages are inflammatory in the colonic intestine. Our study discovered the proportion of CD36+ F4/80+ macrophages were markedly upregulated in active IBD patients and TNBS-induced colitis mice. CD36+ macrophages isolated from the LPMC of the small and large intestine of Balb/c treatment groups(a) 12TNBS, (b) MHS+12TNBS, and (c) MHS+PA mice confirmed these macrophages expressed some level of proinflammatory cytokine TNF-α. Two macrophage ligands, LCFA: Palmitic Acid and PGN, in conjunction or separately, appeared to be two culprits which induced MHS macrophages to produce TNF-α both in vitro and in vivo. It is possible these two ligands may work in concert, however the mouse model has yet to be examined. The precise role(s) of these CD36+ F4/80+ macrophages requires further scientific inquiry and elucidation in the context of intestinal inflammation. It is quite possible understanding the mechanisms and roles of these macrophages will greatly advance our knowledge in the pathophysiology of IBD and potential therapeutic treatments or targets.</p> / Master of Science (MSc)

There are several types of disorders that affect our colon’s ability to function properly such as colorectal cancer, ulcerative colitis, diverticulitis, irritable bowel syndrome and colonic polyps. Automatic detection of these diseases would inform the endoscopist of possible sub-optimal inspection during the colonoscopy procedure as well as save time during post-procedure evaluation. But existing systems only detects few of those disorders like colonic polyps. In this dissertation, we address the automatic detection of another important disorder called ulcerative colitis. We propose a novel texture feature extraction technique to detect the severity of ulcerative colitis in block, image, and video levels. We also enhance the current informative frame filtering methods by detecting water and bubble frames using our proposed technique. Our feature extraction algorithm based on accumulation of pixel value difference provides better accuracy at faster speed than the existing methods making it highly suitable for real-time systems. We also propose a hybrid approach in which our feature method is combined with existing feature method(s) to provide even better accuracy. We extend the block and image level detection method to video level severity score calculation and shot segmentation. Also, the proposed novel feature extraction method can detect water and bubble frames in colonoscopy videos with very high accuracy in significantly less processing time even when clustering is used to reduce the training size by 10 times.

No description available.

Immune-mediated inflammatory diseases (IMID) represent a group of ostensibly unrelated, chronic and highly disabling diseases that preferentially affect different organ systems. IMID are assumed to manifest as a result of the accumulation of genetic, environmental and immunological factors. A fundamental commonality between IMID is the idiopathic nature of disease, and moreover, substantial similarities are apparent in disease etiopathogenesis. The complex assemblage of microbes and their genes that exists within and on the human body, collectively known as the microbiome has emerged as a critical factor in human health and, altered microbial populations within the gastrointestinal tract lumen and mucosa have been linked to several IMID. Accordingly, we conducted several studies investigating the association of the gut microbiome with IMID. Our main study investigated differences in the microbial profile and functional potential of multiple IMID utilizing 16S rDNA amplicon sequencing and analysis of stool. We also investigated the mucosal-associated microbiome in IBD to characterize the microbial populations and their functions residing in distinct gastrointestinal compartments from inflamed and noninflamed mucosa. We also explored a potential environmental factor; specifically assessing whether microbes present in drinking water in low or high incidence areas of IBD might contribute to disease etiology. The findings of these studies are manifold. First, we show important differences of the stool microbial profile in IMID. In doing so, we were able to identify distinct states of gut dysbiosis and have revealed numerous microbes that are consistently or uniquely disproportionate between IMID. Second, we have shown the microbial profile associated with inflamed and noninflamed mucosa and have reported that a localized dysbiosis is not observed in the presence of inflammation. Third, we have revealed that distinct gastrointestinal compartments are comprised of similar microbial communities. Lastly, we have reported the drinking water microbiome to differ between low and high incidence areas of IBD, thus suggesting a potential role in IBD etiology. Understanding the role of the gut microbiome in human disease will enable the development and application of more appropriate therapeutic strategies that specifically target microbes within the gut. / May 2017

Ulcerative colitis (UC) and Crohn’s disease (CD) are the two common forms of inflammatory bowel disease (IBD). They share similar clinical and demographic features as well as harbor key differences in tissue damage and prognosis. Previous studies indicated that they contributed to the increased rick to Colorectal cancer (CRC). However, whether UC and CD share inflammatory signatures still remains controversial. In addition, no inflammatory signatures have been reported on CRC. To answer these questions, a comprehensive study has been conducted on collected microarray datasets. Our analysis suggests that although CD and UC share common inflammatory pathways, they also present difference. Especially, CD patients are likely to have type I response, while UC patients are inclined to undergo type II response. Pathway enrichment analysis on CRC uncovered two potential CRC-specific inflammatory pathways.

The ATP sensitive potassium channel (KATP) in mouse colonic smooth muscle cell is a complex containing a pore forming subunit (Kir6.1) and a sulfonyl urea receptor subunit (SUR2B). These channels are responsible for maintaining the cellular excitability of the smooth muscle cell which in turn regulates the motility patterns in the colon. We used whole-cell voltage-clamp techniques to study the alterations in these channels in smooth muscle cells in experimental model of colitis (colonic inflammation). Colitis was induced in BALB/C mice following an intracolonic administration of trinitrobenzene sulfonic acid (TNBS). KATP currents were measured at Vh -60 mV in high K+ external solution. The dose-response to levcromakalim (LEVC), a KATP channel opener, was significantly shifted to the left in the inflamed smooth muscle cells. Both the affinity and maximal currents induced by LEV were enhanced in inflammation. The EC50 in control was 6259 nM (n=10) and 422 nM (n=8) in inflamed colon while the maximal currents were 9.9 ± 0.71 pA/pF (60 μM) in control and 39.7 ± 8.8 pA/pF (3 μM) following inflammation. Similar to LEVC, KATP currents activated by sodium hydrogen sulfide (NaHS) (10-1000 μM) were significantly greater in inflamed compared to controls. In control cells, pretreatment with 100 µM NaHS shifted the EC50 for LEV-induced currents from 2838 nM (n=6) to 154 nM (n=8). These data suggest that NaHS can act as an allosteric modulator for LEV-induced KATP currents. Decreased colonic motility may result from enhanced KATP activation by increased release of H2S in colitis.

In diploma thesis we deal with inflammatory bowel diseases. The theoretical part describes etiology, pathogenesis, clinical symptoms, out-of-body manifestation and drug therapy. Current knowledge about the relationship between nutrition and disease is described. Since inflammatory bowel diseases are incurable, therapy pays attention to keep the patient in remission and preventing relapse. Nutrition therapy plays an important role in achieving these goals. In the practical part, we deal with the level of nutrition awareness of patients, in the form of a questionnaire and a non- standardized interview. We also study the influence of education on vitamin levels in patients. We determine whether they know the importance of eating and eating nutrients in their illnesses. From the background, it can be appreciated that information resources are insufficient for patients. Patients would also welcome more detailed education, and therefore part of the practical part of the educational material for patients with Crohn's disease. Key words: Crohn's disease, ulcerative colitis, nutrition, education, diet

For over two decades, the study of genetics has been making significant progress towards understanding the causes of common disease. Across a wide range of complex disorders there have been hundreds of associated loci identified, largely driven by common genetic variation. Now, with the advent of next-generation sequencing technology, we are able to interrogate rare and low frequency variation in a high throughput manner for the first time. This provides an exciting opportunity to investigate the role of rarer variation in complex disease risk on a genome-wide scale, potentially o↵ering novel insights into the biological mechanisms underlying disease pathogenesis. In this thesis I will assess the potential of this technology to further our understanding of the genetics of complex disease, using inflammatory bowel disease (IBD) as an example. After first reviewing the history of genetic studies into IBD, I will describe the analytical challenges that can occur when using sequencing to perform case-control association testing at scale, and the methods that can be used to overcome these. I then test for novel IBD associations in a low coverage whole genome sequencing dataset, and uncover a significant burden of rare, damaging missense variation in the gene NOD2, as well as a more general burden of such variation amongst known inflammatory bowel disease risk genes. Through imputation into both new and existing genotyped cohorts, I also describe the discovery of 26 novel IBD-associated loci, including a low frequency missense variant in ADCY7 that approximately doubles the risk of ulcerative colitis. I resolve biological associations underlying several of these novel associations, including a number of signals associated with monocyte-specific changes in integrin gene expression following immune stimulation. These results reveal important insights into the genetic architecture of inflammatory bowel disease, and suggest that a combination of continued array-based genome- wide association studies, imputed using substantial new reference panels, and large scale deep sequencing projects will be required in order to fully understand the genetic basis of complex diseases like IBD.

There is increasing evidence that psychological stress and associated mood disorders are linked with, and can adversely affect the course of inflammatory bowel disease (IBD). Stress is perceived to be relieved by smokers, and this, like a lack of knowledge about its adverse effects, and nicotine dependence, could contribute to continued smoking by patients with Crohn’s disease (CD). Stress has previously been shown to influence disease course in patients with inactive ulcerative colitis (UC) but its influence in acute severe UC is not known. Emerging trial evidence supports the suggestion that psychologically-orientated therapy may ameliorate IBD-associated mood disorders, but there is no strong data yet to indicate that stress management has a beneficial effect on the activity or course of IBD. In addition gut-focussed hypnotherapy has been successfully used in the setting of functional bowel disorders. The 4 main hypotheses tested in thesis are: 1. In patients with IBD: (1) poor knowledge of the effects of smoking on their disease and/or (2) high nicotine dependence explain the higher prevalence of smoking in CD than UC 2. Anxiety, depression and stress are more common and worsen outcome in patients with acute severe UC. 3. Stress management in the form of psychotherapy given by a counsellor has a beneficial effect on the activity and course of IBD. 4. Gut-focussed hypnotherapy reduces the relapse rate in patients with UC. The major findings are as follows: 1. Despite more patients with CD being smokers, they were better informed about the effects of smoking on their own disease than UC patients. Nicotine dependence was no higher in patients with CD than UC. In IBD patients as a whole, nicotine dependence was lower than in smokers’ clinic clients and comparable to that of the general population, suggesting that most IBD patients could be weaned off smoking successfully in the IBD clinic.