Background: Perianal fstulas are a debilitating complication of Crohn’s disease (CD). Due to unknown reasons, CD-associated fstulas are in general more diffcult to treat than cryptoglandular... Show moreBackground: Perianal fstulas are a debilitating complication of Crohn’s disease (CD). Due to unknown reasons, CD-associated fstulas are in general more diffcult to treat than cryptoglandular fstulas (non-CD-associated). Understanding the immune cell landscape is a frst step towards the development of more effective therapies for CD-associated fstulas. In this work, we characterized the composition and spatial localization of disease-associated immune cells in both types of perianal fstulas by high-dimensional analyses. Methods: We applied single-cell mass cytometry (scMC), spectral fow cytometry (SFC), and imaging mass cytometry (IMC) to profle the immune compartment in CD-associated perianal fstulas and cryptoglandular fstulas. An exploratory cohort (CD fstula, n = 10; non-CD fstula, n = 5) was analyzed by scMC to unravel disease-associated immune cell types. SFC was performed on a second fstula cohort (CD, n = 10; non-CD, n = 11) to comprehensively phenotype disease-associated T helper (Th) cells. IMC was used on a third cohort (CD, n = 5) to investigate the spatial distribution/interaction of relevant immune cell subsets. Results: Our analyses revealed that activated HLA-DR+CD38+ effector CD4+ T cells with a Th1/17 phenotype were signifcantly enriched in CD-associated compared with cryptoglandular fstulas. These cells, displaying features of proliferation, regulation, and differentiation, were also present in blood, and colocalized with other CD4+ T cells, CCR6+ B cells, and macrophages in the fstula tracts. Conclusions: Overall, proliferating activated HLA-DR+CD38+ effector Th1/17 cells distinguish CD-associated from cryptoglandular perianal fstulas and are a promising biomarker in blood to discriminate between these 2 fstula types. Targeting HLA-DR and CD38-expressing CD4+ T cells may offer a potential new therapeutic strategy for CD-related fstulas. Show less
Perianal fistulas are defined as pathological connections between the anorectal canal and the perianal skin. Most perianal fistulas are cryptoglandular fistulas, which are thought to originate from... Show morePerianal fistulas are defined as pathological connections between the anorectal canal and the perianal skin. Most perianal fistulas are cryptoglandular fistulas, which are thought to originate from infected anal glands. The remainder of the fistulas mainly arises as complications of Crohn's disease (CD), trauma, or as a result of malignancies. Fistulas in CD are considered as a consequence of a chronic and transmural inflammatory process in the distal bowel and can, in some cases, even precede the diagnosis of CD. Although both cryptoglandular and CD-associated fistulas might look similar macroscopically, they differ considerably in their complexity, treatment options, and healing rate. Therefore, it is of crucial importance to differentiate between these two types of fistulas. In this review, the differences between CD-associated and cryptoglandular perianal fistulas in epidemiology, pathogenesis, and clinical management are discussed. Finally, a flow chart is provided for physicians to guide them when dealing with patients displaying their first episode of perianal fistulas. Show less
Barnhoorn, M.C.; Meulen-de Jong, A.E. van der; Schrama, E.C.L.M.; Plug, L.G.; Verspaget, H.W.; Fibbe, W.E.; ... ; Schepers, K. 2022
Locally applied mesenchymal stromal cells (MSCs) have the capacity to promote the healing of perianal fistulas in Crohn's disease (CD) and are under clinical development for the treatment of... Show moreLocally applied mesenchymal stromal cells (MSCs) have the capacity to promote the healing of perianal fistulas in Crohn's disease (CD) and are under clinical development for the treatment of proctitis in ulcerative colitis (UC). Despite these clinical advances, the mechanism of action of local MSC therapy in inflammatory bowel disease (IBD) is largely unknown. We hypothesized that the local cytokine environment in IBD patients affects the immunomodulatory properties of MSCs. To evaluate this, 11 cytokines were analyzed in inflamed tissues obtained from CD and UC patients. Based on the identified cytokine profiles 4 distinct cytokine mixtures that mimic various inflammatory IBD environments were established. Next, MSCs were cultured in the presence of either of these 4 cytokine mixtures after which the expression of immunomodulatory and tissue regenerative molecules and the capacity of MSCs to modulate T-cell proliferation and dendritic cell (DC) differentiation were assessed. Our data show that MSCs respond, in a cytokine-specific manner, by upregulation of immunomodulatory and tissue regenerative molecules, including cyclooxygenase-2, indoleamine 2,3-dioxygenase, and transforming growth factor-beta 1. Functional studies indicate that MSCs exposed to a cytokine profile mimicking one of the 2 UC cytokine milieus were less effective in inhibition of DC differentiation. In conclusion, our data indicate that cytokine mixes mimicking the local cytokine milieus of inflamed UC colonic or CD fistulas tissues can differentially affect the immunomodulatory and tissue regenerative characteristics of MSCs. These data support the hypothesis that the local intestinal cytokine milieu serves as a critical factor in the efficacy of local MSC treatment. Show less
Barnhoorn, M.C.; Wasser, M.N.J.M.; Roelofs, H.; Maljaars, P.W.J.; Molendijk, I.; Bonsing, B.A.; ... ; Meulen-de Jong, A.E. van der 2020
Background and Aims: The long-term safety and efficacy of allogeneic bone marrow-derived mesenchymal stromal cell [bmMSC] therapy in perianal Crohn's disease [CD] fistulas is unknown. We aimed to... Show moreBackground and Aims: The long-term safety and efficacy of allogeneic bone marrow-derived mesenchymal stromal cell [bmMSC] therapy in perianal Crohn's disease [CD] fistulas is unknown. We aimed to provide a 4-year clinical evaluation of allogeneic bmMSC treatment of perianal CD fistulas.Methods: A double-blind dose-finding study for local bmMSC therapy in 21 patients with refractory perianal fistulising Crohn's disease was performed at the Leiden University Medical Center in 2012-2014. All patients treated with bmMSCs [1 x 10(7) bmMSCs cohort 1, n = 5; 3 x 10(7) bmMSCs cohort 2, n = 5; 9 x 10(7) bmMSCs cohort 3, n = 5] were invited for a 4-year evaluation. Clinical events were registered, fistula closure was evaluated, and anti-human leukocyte antigen [HLA] antibodies were assessed. Patients were also asked to undergo a pelvic magnetic resonance imaging [MRI] and rectoscopy.Results: Thirteen out of 15 patients [87%] treated with bmMSCs were available for long-term follow-up. Two non-MSC related malignancies were observed. No serious adverse events thought to be related to bmMSC therapy were found. In cohort 2 [n = 4], all fistulas were closed 4 years after bmMSC therapy. In cohort 1 [n = 4] 63%, and in cohort 3 [n = 5] 43%, of the fistulas were closed, respectively. In none of the patients anti-HLA antibodies could be detected 24 weeks and 4 years after therapy. Pelvic MRI showed significantly smaller fistula tracts after 4 years.Conclusions: Allogeneic bmMSC therapy for CD-associated perianal fistulas is also in the long-term a safe therapy. In bmMSC-treated patients, fistulas with closure at Week 24 were still closed after 4 years. Show less
Barnhoorn, M.C.; Halteren, A.G.S. van; Pel, M. van; Molendijk, I.; Struijk, A.C.; Jansen, P.M.; ... ; Meulen-de Jong, A.E. van der 2019
