Fibrotic Crohn's Disease Research Articles

Dietetic advocacy for long-term use of exclusive enteral nutrition resulted in high-risk surgical avoidance for complicated fibrotic Crohn's disease – A case report

Surgery is often the only therapeutic option for the management of fibrotic Crohn's disease (FCD). Exclusive Enteral Nutrition (EEN), a nutritionally complete liquid formula, is an effective, safe, short-term treatment for Crohn's Disease. No cases were found internationally of adults with FCD on long-term EEN. We report on clinical outcomes and self-reported quality of life (QoL) after longer-term EEN provision in a patient with complex FCD. "Billie", a 54-year-old female, was admitted with ileal FCD diagnosed in 1985. Previous treatments were unsuccessful, including multiple bowel resections. Billie was chronically bedbound with pain and depression. CDAI (Crohn's disease activity index) score was 640 (<150) with ∼3-20 liquid stools/day, and recurrent partial bowel obstructions. Radiological findings were so severe surgeons reluctantly considered surgery but "one more resection will result in short bowel syndrome". Billie trialled EEN given her QoL was "non-existent". Unable to tolerate the taste, EEN was administered via nasogastric tube. After two months, EEN was administered ongoing via percutaneous endoscopic gastrostomy given patient preference and dietetic advocacy. After eight weeks on EEN, Billie's pain predominantly resolved, with bowel motions of ∼1-2/day, and nil bowel obstructions. Twelve months after EEN commencement, Billie's CDAI was 52, with 'no indication for surgical intervention' and was self-reporting that "life is good". After 18 months, Billie remains asymptomatic, and in clinical remission. This unique case is a wonderful example of dietetic advocacy and showcases the positive impact long-term EEN may have on surgical avoidance, clinical outcomes and self-reported QoL.

Epithelial down‐regulation of the miR‐200 family in fibrostenosing Crohn's disease is associated with features of epithelial to mesenchymal transition

Intestinal mesenchymal cells deposit extracellular matrix in fibrotic Crohn's disease (CD). The contribution of epithelial to mesenchymal transition (EMT) to the mesenchymal cell pool in CD fibrosis remains obscure. The miR‐200 family regulates fibrosis‐related EMT in organs other than the gut. E‐cadherin, cytokeratin‐18 and vimentin expression was assessed using immunohistochemistry on paired strictured (SCD) and non‐strictured (NSCD) ileal CD resections and correlated with fibrosis grade. MiR‐200 expression was measured in paired SCD and NSCD tissue compartments using laser capture microdissection and RT‐qPCR. Serum miR‐200 expression was also measured in healthy controls and CD patients with stricturing and non‐stricturing phenotypes. Extra‐epithelial cytokeratin‐18 staining and vimentin‐positive epithelial staining were significantly greater in SCD samples (P = 0.04 and P = 0.03, respectively). Cytokeratin‐18 staining correlated positively with subserosal fibrosis (P < 0.001). Four miR‐200 family members were down‐regulated in fresh SCD samples (miR‐141, P = 0.002; miR‐200a, P = 0.002; miR‐200c, P = 0.001; miR‐429; P = 0.004); miR‐200 down‐regulation in SCD tissue was localised to the epithelium (P = 0.001‐0.015). The miR‐200 target ZEB1 was up‐regulated in SCD samples (P = 0.035). No difference in serum expression between patient groups was observed. Together, these observations suggest the presence of EMT in CD strictures and implicate the miR‐200 family as regulators. Functional studies to prove this relationship are now warranted.

Multidisciplinary management of gastrointestinal fibrotic stenosis in Crohn's disease.

Crohn's disease (CD) is a chronic inflammatory bowel disease that can involve virtually any part of the gastrointestinal tract. CD complications are the main indications for surgery. A large proportion of these interventions are due to stricturing disease. Although immunosuppressive treatments have been used more frequently during the last 25 years, there is no significant decrease in the need for surgery in patients with CD. Unfortunately, surgery is not curative, as the disease ultimately reoccurs in a substantial subset of patients. To best identify the patients who will require a specific treatment and to plane the most appropriate therapeutic approach, it is important to precisely define the type, the size, and the location of CD stenosis. Diagnostic approaches aim to distinguish fibrotic from inflammatory strictures. Medical therapy is required for inflammatory stenosis. Mechanical treatments are required when fibrotic CD strictures are symptomatic. The choice between endoscopic balloon dilation, stricturoplasty, and laparoscopic or open surgery is based on the presence of perforating complications, the remaining length of small bowel, and the number and length of strictures. The non-hierarchical decision-making process for the treatment of fibrotic CD therefore requires multidisciplinary clinical rounds with radiologists, gastroenterologists, interventional endoscopists, and surgeons.

Inhibition of the mTOR Pathway Alleviates Intestinal Fibrosis Via Suppression of Myofibroblast Proliferation

Intestinal fibrosis is generally considered to be an irreversible stage which gradually evolves in response to prolonged injury or inflammation. The pathophysiology of intestinal fibrosis in IBD is not fully understood. Rapamcyin, an inhibitor of mTOR, has recently been reported to alleviate a severe form of IBD, presumably by improving the inflammatory response by down-regulating the immune system. Recent studies suggest that the mTOR signaling pathway may be involved in transforming growth factor β1(TGFβ1)-dependent fibrogenic processes in several organ systems. Low-dose oral administration of rapamycin reduces fibrogenesis, improves liver function, and prolongs survival in rats with established liver cirrhosis. We hypothesized that rapamycin ameliorates intestinal fibrosis via inhibition of submucosal myofibroblast proliferation. Mice were divided into four groups including control, TNBS alone, rapamycin alone, and both rapamycin and TNBS. Rapamycin (5 mg/kg/day) was administrated intraperitoneally for 6 weeks and TNBS enema weekly for 6 weeks to induce intestinal fibrosis. Mouse colon samples were collected for examination of submucosal collagen deposition by Masson's trichrome blue and myofibroblast proliferation by either aSMA or HIT-5 (focal adhesion protein hydrogen peroxide inducible clone 5). Isolated primary intestinal cells or smooth muscle cell line was treated with TGFβ1 for 72 hours either with or without rapamycin. Myofibroblast cells were identified by staining with aSMA. Colon samples harvested from TNBS-treated mice displayed severe stricture over the distal colon while only mild, patchy erythema and edema observed in the rectum from rapamycin treated TNBS group. While being completely distorted in vehicle treated TNBS group, mucosal crypt architecture was largely preserved in rapamycin treated TNBS group. Colon thickness is an indirect measurement of intestinal inflammation and fibrosis. TNBS treatment induced overall thickening of the colon tissue, especially in the submucosa and muscularis layers, which was markedly prevented by rapamycin treatment. Furthermore, we observed the presence of hyperproliferation of myofibroblasts (aSMA and Hic-5 positive cells) along with significant collagen deposition in the intestine from TNBS treated group. In contrast, intestine from rapamycin treated group exhibited very mild proliferation of myofibroblasts and deposition of collagen. Direct effect of rapamycin on myofibroblast proliferation was also examined in primary intestinal cells and smooth muscle cell line. We observed that rapamycin markedly inhibited proliferation of aSMA and Hic-5 positive cells elicited by TGF-β1in primary intestinal cell cultures. Rapamycin ameliorates intestinal fibrosis in TNBS mouse model. Our in vitro data suggest that rapamycin exerts anti-fibrotic effect in part via direct suppression of myofibroblast proliferation. These findings may have preventive or therapeutic applications in fibrotic Crohn disease.

C1q/TNF-related protein-3 (CTRP-3) is secreted by visceral adipose tissue and exerts antiinflammatory and antifibrotic effects in primary human colonic fibroblasts

The adipokine CTRP-3 (C1q/TNF-related protein-3) belongs to the C1q/TNF-related protein family which antagonizes the effects of lipopolysaccharide (LPS). The aim was to investigate the antiinflammatory and antifibrotic role of CTRP-3 in Crohn's disease (CD). Mesenteric adipose tissue (MAT) of patients with CD or colonic cancer (CC) was resected. Human primary colonic lamina propria fibroblasts (CLPF) were isolated from controls and CD patients. Concentrations of chemokines and cytokines in the supernatants were measured by enzyme-linked immunosorbent assay (ELISA). Expression of connective tissue growth factor (CTGF), collagen I, and collagen III was analyzed by real-time polymerase chain reaction (PCR). Recombinant CTRP-3 expressed in insect cells was used for stimulation experiments. CTRP-3 is synthesized and secreted by MAT resected from patients with CD, ulcerative colitis (UC), CC, and sigma diverticulitis as well as by murine and human mature adipocytes. CTRP-3 had no effect on the basal secretion of MCSF, MIF, or RANTES in MAT of CD and control patients. LPS-stimulation (10 ng/mL) significantly increased IL-8 release in CLPF of CD patients and, to a lesser extent, in cells of controls and of fibrotic CD tissue. CTRP-3 significantly and dose-dependently reduced LPS-induced IL-8 secretion in CLPF within 8 hours after LPS exposure, whereas LPS-induced IL-6 and TNF release was not affected. CTRP-3 inhibited TGF-β production and the expression of CTGF and collagen I in CLPF, whereas collagen III expression remained unchanged. CTRP-3 exerts potent antiinflammatory and antifibrotic effects in CLPF by antagonizing the LPS pathway and by targeting the TGF-β-CTGF-collagen I pathway.

Expression and Regulation of Tissue Inhibitor of Metalloproteinase-1 and Matrix Metalloproteinases by Intestinal Myofibroblasts in Inflammatory Bowel Disease

Intestinal fibrosis and strictures frequently occur in Crohn's disease but not ulcerative colitis. We have recently shown that, compared to myofibroblasts obtained from normal and ulcerative colitis tissue, myofibroblasts isolated from fibrotic Crohn's disease mucosal samples express significantly lower amounts of transforming growth factor (TGF)-beta 3, but the expression of TGF-beta 2 was significantly greater. We now report that in myofibroblast cultures established from fibrotic Crohn's disease mucosal samples there is significantly higher constitutive expression of tissue inhibitor of metalloproteinase (TIMP)-1 compared to similar cells isolated from normal or ulcerative colitis tissue. Myofibroblasts derived from normal mucosa and from mucosa affected by ulcerative colitis or Crohn's disease also expressed matrix metalloproteinase (MMP)-1, MMP-2, and MMP-3 but did not express MMP-9. Recombinant (r) TGF-beta 1 and rTGF-beta 2, but not rTGF-beta 3, induced expression of TIMP-1 in normal intestinal myofibroblasts. These studies illustrate a potential mechanism by which differential expression of isoforms of TGF-beta may lead to excessive deposition of extracellular matrix and stricture formation via TIMP-1-mediated inhibition of MMP activity.

Differential expression of TGF-beta isoforms by normal and inflammatory bowel disease intestinal myofibroblasts.

Intestinal strictures are frequent in Crohn's disease but not ulcerative colitis. We investigated the expression of transforming growth factor (TGF)-beta isoforms by isolated and cultured primary human intestinal myofibroblasts and the responsiveness of these cells and intestinal epithelial cells to TGF-beta isoforms. Normal intestinal myofibroblasts released predominantly TGF-beta(3) and ulcerative colitis myofibroblasts expressed both TGF-beta(1) and TGF-beta(3), whereas in myofibroblast cultures from fibrotic Crohn's disease tissue, there was significantly lower expression of TGF-beta(3) but enhanced release of TGF-beta(2). These distinctive patterns of TGF-beta isoform release were sustained through several myofibroblast passages. Proliferation of Crohn's disease myofibroblasts was significantly greater than that of myofibroblasts derived from normal and ulcerative colitis tissue. In contrast to cells from normal and ulcerative colitis tissue, neutralization of the three TGF-beta isoforms did not affect the proliferation of Crohn's disease intestinal myofibroblasts. Studies on the effect of recombinant TGF-beta isoforms on epithelial restitution and proliferation suggest that TGF-beta(2) may be the least effective of the three isoforms in intestinal wound repair. In conclusion, the enhanced release of TGF-beta(2) but reduced expression of TGF-beta(3) by Crohn's disease intestinal myofibroblasts, together with their enhanced proliferative capacity, may lead to the development of intestinal strictures.