Mesenteric Adipose-derived Stromal Cells From Crohn's Disease Patients Induce Protective Effects in Colonic Epithelial Cells and Mice With Colitis

Exosomes from adipose-derived stem cells regulate M1/M2 macrophage phenotypic polarization to promote bone healing via miR-451a/MIF

OBJECTIVES

Bone defects caused by diseases and trauma are usually accompanied by inflammation, and the implantation of biomaterials as a common repair method has also been found to cause inflammatory reactions, which affect bone metabolism and new bone formation. This study investigated whether exosomes from adipose-derived stem cells (ADSC-Exos) plays an immunomodulatory role in traumatic bone defects and elucidated the underlying mechanisms.

METHODS

ADSC-Exos were loaded by a biomaterial named gelatine nanoparticles (GNPs), physical and chemical properties were analysed by zeta potential, surface topography and rheology. A rat model of skull defect was used for our in vivo studies, and micro-CT and histological staining were used to analyse histological changes in the bone defect area. RT-qPCR and western blotting were performed to verify that ADSC-Exos could regulate M1/M2 macrophage polarization. MicroRNA (miRNA) array analysis was conducted to determine the miRNA expression profiles of ADSC-Exos. After macrophages were treated with a miR-451a mimic, miR-451a inhibitor and ISO-1, the relative expression of genes and proteins was measured by RT-qPCR and western blotting.

RESULTS

In vivo, micro-CT and histological staining showed that exosome-loaded GNPs (GNP-Exos) hydrogel, with good biocompatibility and strong mechanical adaptability, exhibited immunomodulatory effect mainly by regulating macrophage immunity and promoting bone tissue healing. Immunofluorescence further indicated that ADSC-Exos reduced M1 marker (iNOS) expression and increased M2 marker (CD206) expression. Moreover, in vitro studies, western blotting and RT-qPCR showed that ADSC-Exos inhibited M1 macrophage marker expression and upregulated M2 macrophage marker expression. MiR-451a was enriched in ADSC-Exos and targeted macrophage migration inhibitory factor (MIF). Macrophages treated with the miR-451a mimic showed lower expression of M1 markers. In contrast, miR-451a inhibitor treatment upregulated the expression of M1 markers and downregulated the expression of M2 markers, while ISO-1 (a MIF inhibitor) treatment upregulated miR-451a expression and downregulated M1 macrophage marker expression.

CONCLUSION

GNP-Exos can effectively regulate bone immune metabolism and further promote bone healing partly through immune regulation of miR-451a, which may provide a therapeutic direction for bone repair.

Adipose-Derived Stem Cells From Patients With Ulcerative Colitis Exhibit Impaired Immunosuppressive Function

Adipose-derived stem cells (ADSCs) are able to modulate the immune response and are used for treating ulcerative colitis (UC). However, it is possible that ADSCs from patients with inflammatory or autoimmune disorders may show defective immunosuppression. We investigated the use of ADSCs from UC patients for autologous cell treatment, specifically, ADSCs from healthy donors (H-ADSCs) and UC patients (P-ADSCs) in terms of various functions, including differentiation, proliferation, secretion, and immunosuppression. The efficacy of P-ADSCs for treating UC was examined in mouse models of acute or chronic colitis. Both H-ADSCs and P-ADSCs were similar in cell morphology, size, adipogenic differentiation capabilities, and cell surface markers. We found that P-ADSCs had lower proliferative capacity, cloning ability, and osteogenic and chondrogenic differentiation potential than H-ADSCs. P-ADSCs exhibited a diminished capacity to inhibit peripheral blood mononuclear cell proliferation, suppress CD25 and CD69 marker expression, decrease the production of inflammation-associated cytokines interferon-γ and tumor necrosis factor-α, and reduce their cytotoxic effect on A549 cells. When primed with inflammatory cytokines, P-ADSCs secreted lower levels of prostaglandin E2, indoleamine 2, 3-dioxygenase, and tumor necrosis factor-α–induced protein 6, which mediated their reduced immunopotency. Moreover, P-ADSCs exhibited weaker therapeutic effects than H-ADSCs, determined by disease activity, histology, myeloperoxidase activity, and body weight. These findings indicate that the immunosuppressive properties of ASCs are affected by donor metabolic characteristics. This study shows, for the first time, the presence of defective ADSC immunosuppression in UC, indicating that autologous transplantation of ADSCs may be inappropriate for patients with UC.

The Functional Role of Lactoferrin in Intestine Mucosal Immune System and Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), encompassing ulcerative colitis (UC) and Crohn's disease (CD), is one of the main types of intestinal inflammatory diseases with intestine mucosal immune disorder. Intestine mucosal immune system plays a remarkable and important role in the etiology and pathogenesis of IBD. Therefore, understanding the intestine mucosal immune mechanism is a key step to develop therapeutic interventions for IBD. Intestine mucosal immune system and IBD are influenced by various factors, such as inflammation, gut permeability, gut microbiota, and nutrients. Among these factors, emerging evidence show that nutrients play a key role in inflammation activation, integrity of intestinal barrier, and immune cell modulation. Lactoferrin (LF), an iron-binding glycoprotein belonging to transferrin family, is a dietary bioactive component abundantly found in mammalian milk. Notably, LF has been reported to perform diverse biological functions including antibacterial activity, anti-inflammatory activity, intestinal barrier protection, and immune cell modulation, and is involved in maintaining intestine mucosal immune homeostasis. The improved understanding of the properties of LF in intestine mucosal immune system and IBD will facilitate its application in nutrition, clinical medicine, and health. Herein, this review outlines the recent advancements on LF as a potential therapeutic intervention for IBD associated with intestine mucosal immune system dysfunction. We hope this review will provide a reference for future studies and lay a theoretical foundation for LF-based therapeutic interventions for IBD by understanding the particular effects of LF on intestine mucosal immune system.

Obesity and its effects on the esophageal mucosal barrier

Obesity is associated with gastroesophageal reflux disease (GERD) and its complications including reflux esophagitis, Barrett's esophagus, and esophageal adenocarcinoma. Traditionally, these associations have been attributed to the mechanical effect of abdominal fat in increasing intra-abdominal pressure, thereby promoting gastroesophageal reflux and causing disruption of antireflux mechanisms at the esophagogastric junction. However, recent studies suggest that visceral adipose tissue (VAT) produces numerous cytokines that can cause esophageal inflammation and impair esophageal mucosal barrier integrity through reflux-independent mechanisms that render the esophageal mucosa especially susceptible to GERD-induced injury. In this report, we review mechanisms of esophageal mucosal defense, the genesis and remodeling of visceral adipose tissue during obesity, and the potential role of substances produced by VAT, especially the VAT that encircles the esophagogastric junction, in the impairment of esophageal mucosal barrier integrity that leads to the development of GERD complications.

Roles of Adipokines in Digestive Diseases: Markers of Inflammation, Metabolic Alteration and Disease Progression

Adipose tissue is a highly dynamic endocrine tissue and constitutes a central node in the interorgan crosstalk network through adipokines, which cause pleiotropic effects, including the modulation of angiogenesis, metabolism, and inflammation. Specifically, digestive cancers grow anatomically near adipose tissue. During their interaction with cancer cells, adipocytes are reprogrammed into cancer-associated adipocytes and secrete adipokines to affect tumor cells. Moreover, the liver is the central metabolic hub. Adipose tissue and the liver cooperatively regulate whole-body energy homeostasis via adipokines. Obesity, the excessive accumulation of adipose tissue due to hyperplasia and hypertrophy, is currently considered a global epidemic and is related to low-grade systemic inflammation characterized by altered adipokine regulation. Obesity-related digestive diseases, including gastroesophageal reflux disease, Barrett's esophagus, esophageal cancer, colon polyps and cancer, non-alcoholic fatty liver disease, viral hepatitis-related diseases, cholelithiasis, gallbladder cancer, cholangiocarcinoma, pancreatic cancer, and diabetes, might cause specific alterations in adipokine profiles. These patterns and associated bases potentially contribute to the identification of prognostic biomarkers and therapeutic approaches for the associated digestive diseases. This review highlights important findings about altered adipokine profiles relevant to digestive diseases, including hepatic, pancreatic, gastrointestinal, and biliary tract diseases, with a perspective on clinical implications and mechanistic explorations.

Effects of oral bovine lactoferrin on a mouse model of inflammation associated colon cancer

Patients with ulcerative colitis or colonic Crohn's disease have a significantly increased risk of developing colorectal cancer. Bovine lactoferrin (bLF) reportedly inhibited the development of colon cancer in rats and mice, and in a placebo controlled trial, ingestion of bLF inhibited the growth of intestinal polyps. In addition, in a case study, a patient with Crohn's disease was reported to have remained in remission for over 7 years while ingesting 1 g of bLF daily. Thus, bLF has an inhibitory effect on colon carcinogenesis, and it may also promote remission of Crohn's disease. The purpose of this study was to investigate the effects of bLF in a mouse model of colorectal cancer related to irritable bowel disease (IBD). The mice were divided into 4 groups: (i) no treatment; (ii) treated with bLF only; (iii) treated with azoxymethane plus dextran sulfate sodium (AOM + DSS); and (iv) treated with AOM + DSS + bLF. AOM was used to initiate intestinal cancer, and DSS was used to induce IBD-like inflammation in the intestine of the C57BL/6 mice. At the end of the study, the mice treated with AOM + DSS + bLF had a better fecal score, fewer lesions in the colon, and less weight loss than the mice treated with AOM + DSS without bLF. However, there were no statistically significant differences between the two groups with respect to tumor burden.

Adipose-derived mesenchymal stem cells alleviate TNBS-induced colitis in rats by influencing intestinal epithelial cell regeneration, Wnt signaling, and T cell immunity

BACKGROUND

Conventional Crohn’s disease (CD) treatments are supportive rather than curative and have serious side effects. Adipose-derived mesenchymal stem cells (ADSCs) have been gradually applied to treat various diseases. The therapeutic effect and underlying mechanism of ADSCs on CD are still not clear.

AIM

To investigate the effect of ADSC administration on CD and explore the potential mechanisms.

METHODS

Wistar rats were administered with 2,4,6-trinitrobenzene sulfonic acid (TNBS) to establish a rat model of CD, followed by tail injections of green fluorescent protein (GFP)-modified ADSCs. Flow cytometry, qRT-PCR, and Western blot were used to detect changes in the Wnt signaling pathway, T cell subtypes, and their related cytokines.

RESULTS

The isolated cells showed the characteristics of ADSCs, including spindle-shaped morphology, high expression of CD29, CD44, and CD90, low expression of CD34 and CD45, and osteogenic/adipogenic ability. ADSC therapy markedly reduced disease activity index and ameliorated colitis severity in the TNBS-induced rat model of CD. Furthermore, serum anti-sacchromyces cerevisiae antibody and p-anti-neutrophil cytoplasmic antibody levels were significantly reduced in ADSC-treated rats. Mechanistically, the GFP-ADSCs were colocalized with intestinal epithelial cells (IECs) in the CD rat model. GFP-ADSC delivery significantly antagonized TNBS-induced increased canonical Wnt pathway expression, decreased noncanonical Wnt signaling pathway expression, and increased apoptosis rates and protein level of cleaved caspase-3 in rats. In addition, ADSCs attenuated TNBS-induced abnormal inflammatory cytokine production, disturbed T cell subtypes, and their related markers in rats.

CONCLUSION

Successfully isolated ADSCs show therapeutic effects in CD by regulating IEC proliferation, the Wnt signaling pathway, and T cell immunity.

Role of Obesity, Mesenteric Adipose Tissue, and Adipokines in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) are a group of disorders which include ulcerative colitis and Crohn's disease. Obesity is becoming increasingly more common among patients with inflammatory bowel disease and plays a role in the development and course of the disease. This is especially true in the case of Crohn's disease. The recent results indicate a special role of visceral adipose tissue and particularly mesenteric adipose tissue, also known as "creeping fat", in pathomechanism, leading to intestinal inflammation. The involvement of altered adipocyte function and the deregulated production of adipokines, such as leptin and adiponectin, has been suggested in pathogenesis of IBD. In this review, we discuss the epidemiology and pathophysiology of obesity in IBD, the influence of a Western diet on the course of Crohn's disease and colitis in IBD patients and animal's models, and the potential role of adipokines in these disorders. Since altered body composition, decrease of skeletal muscle mass, and development of pathologically changed mesenteric white adipose tissue are well-known features of IBD and especially of Crohn's disease, we discuss the possible crosstalk between adipokines and myokines released from skeletal muscle during exercise with moderate or forced intensity. The emerging role of microbiota and the antioxidative and anti-inflammatory enzymes such as intestinal alkaline phosphatase is also discussed, in order to open new avenues for the therapy against intestinal perturbations associated with IBD.