In the past decades, continuous effort has been paid to deeply understanding the pathophysiology of inflammatory bowel diseases (IBD), such as ulcerative colitis or Crohn’s disease. As the disease ...typically arises as chronic inflammation of the gastrointestinal mucosa, research has been focused on how such an uncontrolled, deleterious immune response may arise and persist in a certain cohort of patients. Based on those immunologic analyses, the establishment of anti-TNF-α therapy, and the following series of biologic agents achieved great success and dramatically changed the therapeutic strategy of IBD patients. However, to guarantee long-term remission of the disease, the therapeutic standard has been raised to achieve “mucosal healing”, which requires complete repair of the gastrointestinal mucosa. Recent studies have revealed the unexpected importance of epithelial cells in the pathophysiology of IBD. The general barrier function as well as the cell lineage-specific functions have been deeply attributed to the development of chronic intestinal inflammation. Also, the groundbreaking establishment of the in vitro intestinal stem cell culture system has opened up a way of developing stem cell transplantation therapy to treat otherwise refractory ulcers that may persist in IBD patients. In this review, we would like to focus on the role of epithelial cells in the pathophysiology of IBD, and also give a perspective to the upcoming development of regenerative therapies that may become one of the therapeutic choices to achieve mucosal healing in refractory patients of IBD.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
We study the transport properties of dilute electrolyte solutions on the basis of the fluctuating hydrodynamic equation, which is a set of nonlinear Langevin equations for the ion densities ...and flow velocity. The nonlinearity of the Langevin equations generally leads to effective kinetic coefficients for the deterministic dynamics of the average ion densities and flow velocity; the effective coefficients generally differ from the counterparts in the Langevin equations and are frequency-dependent. Using the path-integral formalism involving auxiliary fields, we perform systematic perturbation calculations of the effective kinetic coefficients for ion diffusion, shear viscosity, and electrical conductivity, which govern the dynamics on the large length scales. As novel contributions, we study the frequency dependence of the viscosity and conductivity in the one-loop approximation. Regarding the conductivity at finite frequencies, we derive the so-called electrophoretic part in addition to the relaxation part, where the latter has originally been obtained by Debye and Falkenhagen; it is predicted that the combination of these two parts gives rise to the frequency
ω
max
proportional to the salt density, at which the real part of the conductivity exhibits a maximum. The zero-frequency limits of the conductivity and shear viscosity coincide with the classical limiting laws for dilute solutions, derived in different means by Debye, Falkenhagen, and Onsager. As for the effective kinetic coefficients for slow ion diffusions in large length scales, our straightforward calculation yields the cross kinetic coefficient between cations and anions. Further, we discuss the possibility of extending the present study to more concentrated solutions.
Adult stem-cell therapy holds promise for the treatment of gastrointestinal diseases. Here we describe methods for long-term expansion of colonic stem cells positive for leucine-rich repeat ...containing G protein-coupled receptor 5 (Lgr5(+) cells) in culture. To test the transplantability of these cells, we reintroduced cultured GFP(+) colon organoids into superficially damaged mouse colon. The transplanted donor cells readily integrated into the mouse colon, covering the area that lacked epithelium as a result of the introduced damage in recipient mice. At 4 weeks after transplantation, the donor-derived cells constituted a single-layered epithelium, which formed self-renewing crypts that were functionally and histologically normal. Moreover, we observed long-term (>6 months) engraftment with transplantation of organoids derived from a single Lgr5(+) colon stem cell after extensive in vitro expansion. These data show the feasibility of colon stem-cell therapy based on the in vitro expansion of a single adult colonic stem cell.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Intestinal organoids are fundamental in vitro tools that have enabled new research opportunities in intestinal stem cell research. Organoids can also be transplanted in vivo, which enables them to ...probe stem cell potential and be used for disease modeling and as a preclinical tool in regenerative medicine. Here we describe in detail how to orthotopically transplant epithelial organoids into the colon of recipient mice. In this assay, epithelial injury is initiated at the distal part of colon by the administration of dextran sulfate sodium, and organoids are infused into the luminal space via the anus. The infused organoids subsequently attach to the injured region and rebuild a donor-derived epithelium. The steps for cell infusion can be completed in 10 min. The assay has been applied successfully to organoids derived from both wild-type and genetically altered epithelial cells from adult colonic and small intestinal epithelium, as well as fetal small intestine. This is a versatile protocol, providing the technical basis for transplantation following alternative colonic injury models. It has been used previously for functional assays to probe cellular potential, and formed the basis for the first in-human clinical trial using colonic organoid transplantation therapy for intractable cases of ulcerative colitis.
Hepatitis C virus infection is characterized by chronic liver inflammation and fibrogenesis, leading to end-stage liver failure and hepatocellular carcinoma over the course of 20 to 30 years. It ...seems not only the chronicity of hepatitis C but also the presence of the virus in non-hepatic tissues creates a favorable environment for the potential development of pathogenic impacts on extrahepatic systems and organs. Numerous extra-hepatic manifestations have been reported in association with HCV infection, all of which can substantially affect morbidity, mortality, and quality of life. With the recent development of DAAs, antiviral treatment can cure almost all patients with HCV infection, even those intolerant of or unresponsive to IFN treatment, and several large multicenter studies have confirmed the association of DAA-induced SVR with reductions in liver-related and liver-unrelated complications, such as cardiovascular events, end stage renal disease, and so on. Because, in addition to liver-related diseases, extrahepatic lesions are threatening for patients, it is important to eradicate the virus before these progress and affect life prognosis; in other words, patients should be treated before reaching the point of no return. Tailored surveillance with biomarkers such as M2BPGi and Ang-2, which can be used to identify patients with an elevated risk of EHM, and early prevention or treatment for these patients could improve the morbidity, mortality and QOL. Advancement of both basic and clinical research in this field including the development of more precise biomarkers is highly anticipated.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Leucine-rich alpha-2 glycoprotein (LRG) is a newly studied biomarker for inflammatory diseases. This study aimed to investigate whether LRG can be used for evaluating transmural activity in patients ...with Crohn's disease (CD).
We performed magnetic resonance enterography (MRE) in 227 consecutive patients with CD from June 2020 to August 2021. We prospectively compared MRE findings with clinical and laboratory data including LRG. MRE was evaluated using 2 validated scoring systems, and transmural inflammation was defined as having a maximum simplified magnetic resonance index of activity (sMaRIA) score of ≥4 and a 5-point classification score of ≥9, respectively.
The correlation between LRG and the total MRE score showed a positive correlation ( r = 0.576 for the sMaRIA score, P < 0.01, and r = 0.633 for the 5-point score, P < 0.01). Serum concentrations of LRG significantly increased as MRE scores increased ( P < 0.01). The area under the curve of LRG for a sMaRIA score of ≥4 and a 5-point score of ≥9 was 0.845 and 0.869, respectively, which was significantly higher than that of CDAI ( P < 0.01) or C-reactive protein ( P < 0.01). LRG levels of ≥14 μg/mL had a 67% sensitivity and 90% specificity for a sMaRIA score of ≥4 and a 73% sensitivity and 89% specificity for a 5-point score of ≥9. Patients with high LRG levels were also strongly associated with CD-related hospitalization, surgery, and clinical relapse compared with those with low LRG levels ( P < 0.01 for all).
LRG is a highly accurate serum biomarker for detecting transmural activity in patients with CD. Results need to be validated in further multicenter studies.
Inflammatory bowel disease (IBD) is characterized by idiopathic and chronic inflammation arising elsewhere within the gastrointestinal tract. Consequently, the mucosal tissue is destroyed during the ...active phase of the disease, and therefore, spontaneous repair of damaged tissue is required to restore the function and long-term homeostasis of the intestinal mucosa. Also, in patients with refractory Crohn's disease, loss of massive intestinal function can lead to short bowel syndrome or may lead to fatal intestinal failure.
The concept of mucosal healing shares the idea that both regulation of mucosal inflammation and repair of the damaged mucosa are critical to achieve the ideal clinical outcome in patients with IBD. However, current treatments lack the option of those targeted to mucosal repair, and therefore, patients must achieve mucosal healing depending on their intrinsic system. To counteract inflammation-induced mucosal damage, various biologics or cell-based treatments are currently being developed. In the early developmental phase, various growth factors have been tested for their ability to promote mucosal repair. However, most of these factors did not show clinical benefit, except the recombinant glucagon-like peptide-2 (GLP-2). On the contrary, cell-based treatments are rapidly emerging, using both somatic stem cells and pluripotent stem cells.
In this review, we focus on the current state of factor-based or cell-based regenerative medicine in the treatment of IBD. Additionally, we would like to introduce current examples of tissue engineering technologies and provide future prospects for the application of regenerative medicine in IBD.
In Japan and other Asian countries, increased fat uptake induced by a westernized diet is thought to be associated with an increased incidence of inflammatory bowel disease, colorectal cancer and ...food allergies; however, the mechanism for this remains unclear. High-fat diet (HFD)-fed mice are common animal models used to examine the effect of fat intake in vivo. HFDs are reported to exacerbate DSS-induced colitis and intestinal tumorigenesis, but the effect of HFDs on the intestines before disease induction is often overlooked. We found that the intestinal and gut-associated lymphoid tissue (GALT) morphology of HFD-fed mice differed from that of standard diet (SD)-fed mice. To clarify the mechanism by which fat intake increases intestinal diseases, we analyzed the morphological and immunological aspects of the intestines of HFD-fed mice as well as the molecular mechanisms and physiology.
Feeding an HFD for 3 weeks induced atrophy of the small intestine, colon and GALT and reduced the number of small intestinal intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs). Feeding an HFD for only one day reduced the number of small intestinal (SI)-IELs and SI-LPLs. The effect of feeding a 3-week HFD continued for 2 weeks after returning to the SD. The effect of the HFD on the intestinal immune system was independent of the gut microbes. We hypothesized that the cytotoxicity of the abundant HFD-derived free fatty acids in the intestinal lumen impairs the intestinal immune system. Both saturated and unsaturated free fatty acids were toxic to intestinal T-cells in vitro. Orally administering free fatty acids reduced the number of SI-IELs and LPLs. Using a lipase inhibitor to reduce the luminal free fatty acids attenuated the HFD-induced changes in the intestinal immune system, while using a statin to reduce the serum free fatty acids did not. Thus, HFD-induced free fatty acids damaged the intestines; this effect was termed “intestinal lipotoxicity”. Because sustained reduction of SI-LPLs after HFD feeding exacerbated indomethacin-induced small intestinal damage, lipotoxicity to the human intestines incurred by consuming a westernized diet in Japan may increase intestinal diseases such as IBD, colorectal cancer or food allergies.
•Feeding a high-fat diet (HFD) induced atrophy of the intestines.•Feeding an HFD reduced the number of small intestinal T-cells, too.•We defined these phenotypes as termed intestinal lipotoxicity.•Intestinal lipotoxicity was caused by cytotoxicity from HFD-derived free fatty acids.•Intestinal lipotoxicity exacerbated indomethacin-induced small intestinal damage.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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