Mesenchymal stromal cells: an opportunity to treat chronic inflammatory intestinal conditions

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.

Clinical phenotype and mortality in patients with idiopathic small bowel villous atrophy: a dual-centre international study

OBJECTIVE

Causes of small-bowel villous atrophy (VA) include coeliac disease (CD), its complications and other rare non-coeliac enteropathies. However, forms of VA of unknown aetiology may also exist. We defined them as idiopathic VA (IVA). To retrospectively classify the largest cohort of IVA patients and compare their natural history with CD.

METHODS

Notes of 76 IVA patients attending two tertiary centres between January 2000 and March 2019 were retrospectively reviewed. CD, its complications and all the known causes of VA were excluded in all of them. Persistence of VA during follow-up and lymphoproliferative features were used to retrospectively classify IVA, as follows. Group 1: IVA with spontaneous histological recovery (50 patients). Group 2: persistent IVA without lymphoproliferative features (14 patients). Group 3: persistent IVA with lymphoproliferative features (12 patients). Survival was compared between IVA groups and 1114 coeliac patients. HLA was compared between IVA patients, coeliac patients and appropriate controls.

RESULTS

Five-year survival was 96% in IVA group 1, 100% in IVA group 2, 27% in IVA group 3 and 97% in CD. On a multivariate analysis hypoalbuminemia (P = 0.002) and age at diagnosis (P = 0.04) predicted mortality in IVA. Group 2 showed association with HLA DQB1*0301 and DQB1*06.

CONCLUSION

IVA consists of three groups of enteropathies with distinct clinical phenotypes and prognoses. Mortality in IVA is higher than in CD and mainly due to lymphoproliferative conditions necessitating more aggressive therapies.

Serum-Free Medium Enhances the Therapeutic Effects of Umbilical Cord Mesenchymal Stromal Cells on a Murine Model for Acute Colitis

The usage of animal serum may ultimately prevent the application of ex vivo cultured mesenchymal stromal cells (MSCs) in a clinical setting due to safety concerns and batch-to-batch variability. Increasing regulatory pressure to limit use of animal serum has been issued and serum-free, xeno-free, and chemically defined media (S&XFM-CD) is encouraged to replace serum-containing media (SCM) in the stem cell preparation process. We previously developed a S&XFM-CD for the expansion of umbilical cord-derived MSCs (UCMSCs). Different culture conditions affect the function of MSCs, which may further affect the therapeutic efficiency and mechanisms of action. In this study, we compared the therapeutic effect and mechanism of UCMSCs in S&XFM-CD (UCMSC^S&XFM−CD) in experimental colitis with those in SCM (UCMSC^SCM). UCMSC^S&XFM−CD exhibited better therapeutic effects than UCMSC^SCM by body weight, disease activity index, and histological colitis score. UCMSC^S&XFM−CD or UCMSC^SCM migrated to the inflammation site of injured colon, but exhibited low levels of recruitment and persistence. Systemic depletion of endogenous macrophages impaired the therapeutic effects of UCMSC^SCM and UCMSC^S&XFM−CD. Furthermore, UCMSC^S&XFM−CD more markedly promoted intestinal macrophage polarisation from M1 to M2 phenotype to produce higher levels of IL-10 and lower levels of TNF-α in colon tissue than UCMSC^SCM, while a higher level of IL-4 was produced in UCMSC^SCM-treated group. UCMSC^S&XFM−CD cocultured with RAW264.7 cells in a transwell system promoted the release of TSG-6 and IL-6, whereas UCMSC^SCM increased PGE₂ levels. Taken together, we demonstrated that UCMSCs in S&XFM-CD exhibited improved therapeutic effects with altered cytokine secretion in an experimental acute colitis model.

Cell membrane and bioactive factors derived from mesenchymal stromal cells: Cell-free based therapy for inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders of the gastrointestinal tract associated with multifactorial conditions such as ulcerative colitis and Crohn’s disease. Although the underlying mechanisms of IBD remain unclear, growing evidence has shown that dysregulated immune system reactions in genetically susceptible individuals contribute to mucosal inflammation. However, conventional treatments have been effective in inducing remission of IBD but not in preventing the relapse of them. In this way, mesenchymal stromal cells (MSC) therapy has been recognized as a promising treatment for IBD due to their immunomodulatory properties, ability to differentiate into several tissues, and homing to inflammatory sites. Even so, literature is conflicted regarding the location and persistence of MSC in the body after transplantation. For this reason, recent studies have focused on the paracrine effect of the biofactors secreted by MSC, especially in relation to the immunomodulatory potential of soluble factors (cytokines, chemokines, and growth factors) and extracellular vehicles that are involved in cell communication and in the transfer of cellular material, such as proteins, lipids, and nucleic acids. Moreover, treatment with interferon-γ, tumor necrosis factor-α, and interleukin-1β causes MSC to express immunomodulatory molecules that mediate the suppression via cell-contact dependent mechanisms. Taken together, we present an overview of the role of bioactive factors and cell membrane proteins derived from MSC as a cell-free therapy that can improve IBD treatment.